全文获取类型
收费全文 | 506篇 |
免费 | 4篇 |
专业分类
教育 | 274篇 |
科学研究 | 192篇 |
各国文化 | 4篇 |
体育 | 8篇 |
文化理论 | 4篇 |
信息传播 | 28篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 27篇 |
2017年 | 25篇 |
2016年 | 15篇 |
2015年 | 19篇 |
2014年 | 18篇 |
2013年 | 60篇 |
2012年 | 14篇 |
2011年 | 18篇 |
2010年 | 24篇 |
2009年 | 23篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 7篇 |
2002年 | 11篇 |
2001年 | 16篇 |
2000年 | 13篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1993年 | 8篇 |
1992年 | 15篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有510条查询结果,搜索用时 31 毫秒
31.
A simple design method for the cosine-modulated filter banks using weighted constrained least square technique 总被引:1,自引:0,他引:1
This paper presents a simple and efficient design method for cosine-modulated filter banks with prescribed stopband attenuation, passband ripple, and channel overlap. The method casts the design problem as a linear minimization of filter coefficients such that their value at ω=π/2M is 0.707, which results in a simpler, more direct design procedure. The weighted constrained least squares technique is exploited for designing the prototype filter for cosine modulation (CM) filter banks. Several design examples are included to show the increased efficiency and flexibility of the proposed method over the exiting methods. An application of the proposed method is considered in the area of sub-band coding of the ECG and speech signals. 相似文献
32.
Surface features such as uneven playing surfaces, low impact absorption capacity and inappropriate friction/traction characteristics are connected with injury prevalence whereas force impact during foot strike has been suggested to be an important mechanism of intravascular haemolysis during running. We aimed to evaluate intravascular haemolysis during running and compare the effect of running on two different types of surfaces on haemolysis. We selected two surfaces (asphalt and grass) on which these athletes usually run. Participants were randomly assigned to group A (asphalt) or group B (grass) with 10 athletes in each group. Each athlete completed one hour of running at the calculated target heart rate (60-70%). Venous blood samples were collected before and immediately after running. We measured unconjugated bilirubin (UBR) (mg · dl(-1)), lactate dehydrogenase (LDH) (μ · ml(-1)), haemoglobin (g · l(-1)) and serum ferritin (ng · ml(-1)) as indicators of haemolysis. Athletes who ran on grass demonstrated an increase in the haematological parameters (UBR: P < 0.01, LDH: P < 0.05) when compared to athletes who ran on asphalt (UBR: P < 0.05, LDH: P = 0.241). Our findings indicate that intravascular haemolysis occurs significantly after prolonged running. Furthermore, we conclude that uneven grass surface results in greater haemolysis compared to asphalt road. 相似文献
33.
Sanjeev Shruthi Molly Mary Thabah Bobby Zachariah Vir Singh Negi 《Indian journal of clinical biochemistry : IJCB》2021,36(2):185
To study oxidative stress in systemic lupus erythematosus (SLE) by estimating serum oxidised LDL (OxLDL), 8-hydroxy-2′-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and total anti-oxidant status and to correlate with SLE disease activity and disease damage. Eighty SLE patients satisfying the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) 2012 criteria and 80 healthy controls were studied. Exclusion criteria were infections, renal insufficiency, other connective tissue diseases, drug-induced lupus, smoking, alcohol consumption. Disease activity was measured by SLE disease activity index-2 K (SLEDAI), disease damage was quantified by SLICC-Damage Index (SDI). Sera was tested for OxLDL, 8-OHdG, and total antioxidant status (TAS) by double-antibody sandwich ELISA; MDA measured by Colorimetric assay. Oxidative stress markers were compared between group1- controls, group 2-mildly active SLE (SLEDAI ≤ 5), group 3- moderate to highly active SLE (SLEDAI ≥ 6). SLE patients had significantly higher MDA, 8-OHdG and lower TAS when compared to healthy controls, while OxLDL was similar in the three groups. MDA, 8-OHdG were significantly higher, TAS lower in group 3 compared to group 2. MDA had positive correlation with SLEDAI, TAS negatively correlated with SLEDAI. SLE with neuropsychiatric manifestations, vasculitis, anti-sdDNA antibodies had higher MDA, MDA/TAS ratio. SLE patients with thrombocytopenia, and vasculitis had higher OxLDL. Only OxLDL was significantly higher in those patients who have SDI > 1. SLE patients have increased oxidative stress measured by increases in MDA, 8-OHdG, and lower total antioxidant status that was associated with disease activity and some disease manifestations. However only OxLDL was associated with damage. 相似文献
34.
Virtual education in universities: a technological imperative 总被引:1,自引:0,他引:1
John O'Donoghue Gurmak Singh & Lisa Dorward 《British journal of educational technology : journal of the Council for Educational Technology》2001,32(5):511-523
Many educational journals have debated the issue of the "virtual university". As technology is improving and evolving, such "virtuality" becomes a reality. The forecasts are that, in the not too distant future, it will be possible for courses to be completed solely by the use of the World Wide Web or Internet. These "virtual classrooms" will take the place of the solid buildings where students currently attend lectures, at set times in set rooms. The information will be gathered at the student's convenience and assignments will be handed in via this medium. There is potentially an advantage for everyone involved, from the reduced building resource costs to the availability of teaching support 24 hours a day, 7 days a week
Whilst many of these studies identify the benefits of technology in education there are dissenting voices from many other quarters. However there are also arguments identifying the disadvantages to the technology based delivery systems proposed. Either way, there are going to be radical changes in the methods which students will use to tackle the workload involved in studying towards a degree. This paper will explore both sides of the argument. The main contention of this paper is that technology undoubtedly will offer many benefits for the learner, however, the pitfalls need careful consideration in the design of the learning environment. This paper uses examples from educational institutions across different cultures. 相似文献
Whilst many of these studies identify the benefits of technology in education there are dissenting voices from many other quarters. However there are also arguments identifying the disadvantages to the technology based delivery systems proposed. Either way, there are going to be radical changes in the methods which students will use to tackle the workload involved in studying towards a degree. This paper will explore both sides of the argument. The main contention of this paper is that technology undoubtedly will offer many benefits for the learner, however, the pitfalls need careful consideration in the design of the learning environment. This paper uses examples from educational institutions across different cultures. 相似文献
35.
36.
Parlo Singh 《International Journal of Inclusive Education》2013,17(1):3-21
In this paper an analysis is undertaken of the accounts of pedagogic work provided by para-educational personnel working in two government-funded schools situated in a low socio-economic area of an Australian city. Specifically, the paper examines the accounts of two para-educational personnel who identified as Samoan/Pacific Islander and worked to improve the educational outcomes of students from the local Samoan/Pacific Islander community. It is argued that the pedagogic work of para-educational personnel may play an important role in redistributing discursive (informational) resources transmitted through schooling institutions. However, the positioning of para-educational personnel in the field of the local community and the field of education regulates the form/modality of pedagogic work, that is, what is taught and how it is taught. Moreover, the content and form of pedagogic work has the potential for realising inclusive and/or exclusive relations for students from disadvantaged backgrounds. 相似文献
37.
This paper examines the construction of ‘socially just’ curriculum renewal initiatives for Samoan students in a low socio-economic secondary school. Basil Bernstein's concept of recontextualization is used to investigate the implementation of Queensland's Social Justice Strategy at the school level. Interview data provided by the school's first two ‘social justice coordinators’ is analysed, focussing on the categorizations of students and discourses operative within the reform initiatives. Shifts in what counted as socially just curriculum for Samoan students are documented. The focus is on the varying strength of the boundaries of cultural categories (i.e. ‘Samoan’) and on tensions over the emphasis on the cultural knowledge of community representatives and the professional knowledge of school educators. The findings make explicit implications for the distribution of discursive resources to the Samoan students and, hence, life chances in a world in which English is a tool needed by young Australians irrespective of their cultural background. 相似文献
38.
Young people's need for sex education is evidenced by their typically early initiation of sexual activity, the often involuntary context within which they have sexual intercourse, high‐risk sexual behaviours and the inadequate levels of knowledge of means of protecting their sexual health. The earliness of initiation of sexual intercourse has implications for the age by which sexuality education should be provided. The extent and context of sexual behaviour is a firm indicator of the need for sex education as well as for counselling, information and services related to sexual and reproductive health. Apart from behaviours, information on the extent of knowledge and accuracy of knowledge about risks to sexual health and about means of preventing unhealthy or undesired outcomes are important indicators of young people's need for information to help them make choices and to engage in safe and healthy behaviours. Such measures of behaviour and knowledge can also be relevant and valid indicators of the effectiveness of sex education interventions. The context with which young people live and key characteristics such as school attendance and literacy are important considerations in providing information and in evaluating interventions. 相似文献
39.
Puneet Singh Gill 《Sex education》2013,13(6):686-696
Sex education, especially in the southeastern USA, remains steeped in an Abstinence-Only-Until-Marriage (AOUM) approach, which sets up barriers to the education of sexually active students. Research confirms that science education has the potential to facilitate discussion of controversial topics, including sex education. Science teachers in the USA, however, may face legislative challenges influenced by the local political and social climate. This study aims to understand how science teachers address and construct curriculum related to sex education topics in AOUM environments. A Foucauldian lens is used to examine how teachers’ discourses influence decision-making concerning sex education. Findings from the study suggest that the AOUM curriculum influences the ways in which science teachers make decisions about the curriculum and taboo subjects such as homosexuality and abortion. The study also suggests that students learn about sex and sexuality in ways directly related to their personal experiences. Finally, study findings suggest that personal controversies, such as those relating to sexual health, can be integrated into science education through forms of teacher education and professional development attuned to the different ways that AOUM policies affect science teaching practices. 相似文献
40.
In the natural sciences, collecting, cataloguing, and comparing living specimens have long been a popular, collaborative mode of discovery and learning. New species are discovered, and the relationships between species are theorized. From Aristotle's “History of Animals” to Darwin's “On the Origin of Species”, and beyond, this process of learning through expedition has yielded bountiful knowledge and insights to students of science. In this paper, we propose that expeditionary learning can be applied to a softer science: the field of information systems. In the field of information systems, specimens (information systems) are created by humans, evolving with great speed. Expeditionary learning—where students collaboratively discover, catalog, and compare rapidly evolving information system specimens—is an innovative approach for learners in the IS field, and is effective in increasing IS program visibility and delivering significant, measurable community impact. Our results indicate that learning by expedition has a strong, positive community impact through educating external learners (such as high school and community college students, and the general public), and compares favorably to conventional experiential and service learning styles. Though expeditionary learning does not yield improved course evaluations, we demonstrate that learners’ perceived self‐knowledge and intentions to pursue the subject area are improved. 相似文献