全文获取类型
收费全文 | 4979篇 |
免费 | 79篇 |
国内免费 | 20篇 |
专业分类
教育 | 3364篇 |
科学研究 | 646篇 |
各国文化 | 30篇 |
体育 | 380篇 |
综合类 | 6篇 |
文化理论 | 33篇 |
信息传播 | 619篇 |
出版年
2022年 | 38篇 |
2021年 | 47篇 |
2020年 | 87篇 |
2019年 | 120篇 |
2018年 | 158篇 |
2017年 | 195篇 |
2016年 | 156篇 |
2015年 | 117篇 |
2014年 | 159篇 |
2013年 | 790篇 |
2012年 | 132篇 |
2011年 | 137篇 |
2010年 | 122篇 |
2009年 | 103篇 |
2008年 | 115篇 |
2007年 | 136篇 |
2006年 | 105篇 |
2005年 | 72篇 |
2004年 | 86篇 |
2003年 | 79篇 |
2002年 | 62篇 |
2001年 | 105篇 |
2000年 | 130篇 |
1999年 | 89篇 |
1998年 | 73篇 |
1997年 | 63篇 |
1996年 | 62篇 |
1995年 | 42篇 |
1994年 | 46篇 |
1993年 | 33篇 |
1992年 | 75篇 |
1991年 | 68篇 |
1990年 | 60篇 |
1989年 | 62篇 |
1988年 | 74篇 |
1987年 | 58篇 |
1986年 | 78篇 |
1985年 | 70篇 |
1984年 | 55篇 |
1983年 | 69篇 |
1982年 | 54篇 |
1981年 | 40篇 |
1980年 | 29篇 |
1979年 | 52篇 |
1978年 | 49篇 |
1977年 | 37篇 |
1976年 | 41篇 |
1975年 | 31篇 |
1974年 | 33篇 |
1973年 | 33篇 |
排序方式: 共有5078条查询结果,搜索用时 31 毫秒
131.
T. Malati G. Rajani Kumari P. V. L. N. Murthy Ch. Ram Reddy B. Surya Prakash 《Indian journal of clinical biochemistry : IJCB》2006,21(1):34-40
Prostate Specific Antigen (PSA) has emerged as the most applicable and important tumor marker for carcinoma prostate. In the
present study PSA was determined in serum of healthy subjects, patients of benign prostate hypertrophy (BPH) and Carcinoma
Prostate (Ca−P) to evaluate its diagnostic efficiency in day to day management of prostate cancer patients and in differentiating
patients of early prostate cancer from those with BPH. Receiver operating characteristic curve (ROC) revealed 2 ng/ml and
10 ng/ml cut off serum PSA level for BPH and untreated carcinoma prostate patients (Ca−P). An extremely significant increase
(P<0.0001) was observed in mean PSA concentration in BPH patients and adenocarcinoma prostate patients when compared to healthy
males. Clinical relevance of PSA was highlighted by a case study of cancer patient prior to any therapy till death. 相似文献
132.
C.S. Badue R. Baeza-Yates B. Ribeiro-Neto A. Ziviani N. Ziviani 《Information processing & management》2007
The performance of parallel query processing in a cluster of index servers is crucial for modern web search systems. In such a scenario, the response time basically depends on the execution time of the slowest server to generate a partial ranked answer. Previous approaches investigate performance issues in this context using simulation, analytical modeling, experimentation, or a combination of them. Nevertheless, these approaches simply assume balanced execution times among homogeneous servers (by uniformly distributing the document collection among them, for instance)—a scenario that we did not observe in our experimentation. On the contrary, we found that even with a balanced distribution of the document collection among index servers, correlations between the frequency of a term in the query log and the size of its corresponding inverted list lead to imbalances in query execution times at these same servers, because these correlations affect disk caching behavior. Further, the relative sizes of the main memory at each server (with regard to disk space usage) and the number of servers participating in the parallel query processing also affect imbalance of local query execution times. These are relevant findings that have not been reported before and that, we understand, are of interest to the research community. 相似文献
133.
134.
Two experiments examined whether 18-month-olds learn from emotions directed to a third party. Infants watched an adult perform actions on objects, and an Emoter expressed Anger or Neutral affect toward the adult in response to her actions. The Emoter then became neutral and infants were given access to the objects. Infants' actions were influenced by their memory of the Emoter's affect. Moreover, infants' actions varied as a function of whether they were currently in the Emoter's visual field. If the previously angry Emoter was absent (Experiment 1) or turned her back (Experiment 2), infants did not use the prior emotion to regulate their behavior. Infants learn from emotional eavesdropping, and their subsequent behavior depends on the Emoter's orientation toward them. 相似文献
135.
Kohlberg's (1966) hypothesis that the attainment of gender constancy motivates children to attend to gender norms was reevaluated by examining these links in relation to age. Ninety-four 3- to 7-year-old children were interviewed to assess whether and how constancy mediates age-related changes in gender-related beliefs. As expected, results indicated a general pattern of an increase in stereotype knowledge, the importance and positive evaluation of one's own gender category, and rigidity of beliefs between the ages of 3 and 5. Moreover, the stability phase, rather than full constancy, mediated some of these relations. After age 5, rigidity generally decreased with age, with relations primarily mediated by consistency. 相似文献
136.
We document some basic facts about how liquids behave in the low gravity of outer space and how this poses challenges to space
scientists and engineers who need to design and test systems that handle fluids in outer space while working in the 1-g environment
on Earth.
N Ananthkrishnan is Director, Coral Digital Technologies (P) Ltd, a Bangalore-based company working in the area of multidisciplinary
simulation and system integration of aerospace, naval and surface vehicles, and in the design and development of autonomous
unmanned/micro air vehicles. 相似文献
137.
An Autonomist Biopolitics of Education: Reproduction,Resistance, and the Specter of Constituent Bíos
Gregory N. Bourassa 《Educational theory》2019,69(3):305-325
In considering the enigmatic relationships between philosophy, politics, and pedagogy, this essay attempts to map some of the currents in educational scholarship, particularly those running between reproduction theories and resistance theories. While these two theoretical frameworks have been at odds with one another, Gregory Bourassa suggests that both share orthodox commitments that prevent them from appreciating the constituent dimensions of revolutionary subjectivity. In seeking an alternative orientation, Bourassa proposes an autonomist biopolitics of education. This framework inverts the traditional circuits of resistance and suggests that schools follow behind and resist the constituent life forms (constituent bíos) of students. If resistance theory only attempts to identify the ways in which students resist school practices, it risks obscuring the potentiality of constituent bíos as a social ontology that is primary, always already present, and subject to the resistant practices of the school. Therefore, a key contribution of this essay is its development of an autonomist biopolitics of education. Within this framework, constituent bíos is recognized as the foundational and constitutive motor to which schools are constantly reacting. The adoption of this perspective, alongside more conventional understandings of resistance, offers a more nuanced conception of the relation between forms of life and schools. 相似文献
138.
Gendered patterns in mathematics and science interest emerge in early childhood, develop over time, and ultimately reflect advanced course selection in secondary education. During the crucial time adolescents become aware of their strengths and interests and specialize accordingly, they get the opportunity to participate in out-of-school learning programs such as mathematics and science competitions. This raises the question whether mathematics and science competitions contribute to gender equity by equally promoting female and male interests. In this article, we present a systematic review on gender differences and the mechanisms explaining success and failure in mathematics and science competitions. On an international level, we found large gender differences regarding participation in all Olympiads with the exception of the biology Olympiad. In fairs and national Olympiads, overall participation rates were not gendered as such, but females preferred biology topics whereas males preferred physics related topics. Male and female achievement in fairs was comparable, but males clearly outperformed female participants at the Olympiads, with the smallest differences in the biology Olympiad. Variables and theoretical frameworks explaining participation and achievement and the role of gender in mathematics and science competitions are discussed. We suggest that gender stereotypes, through their influence on self-concept and interest, play an important role in the mechanisms resulting in low female participation rates in and beyond mathematics and science competitions (especially in physics and chemistry). The mechanisms we found explaining female representation during a national selection competition might be considered as reflecting those in female mathematics or science careers and could thus serve as food for thought on countering the gender gap in mathematics and science. 相似文献
139.
Maruschka N. Sluiter Albert W. Wienen Ernst D. Thoutenhoofd Jeannette M. Doornenbal Laura Batstra 《Psychology in the schools》2019,56(8):1259-1270
The increased use of Attention Deficit/Hyperactivity Disorder (ADHD) medication by children has led to growing concerns. In a previous study, we found that many of the teachers that were interviewed about ADHD spontaneously associated ADHD with medication. The present study is a qualitative reanalysis of what precisely these 30 primary school teachers had spontaneously said about medication in our previous semi‐structured interviews on ADHD. Almost all respondents had experience with pupils taking ADHD medication. The majority of spontaneously mentions medication as the treatment of ADHD. Attitudes towards ADHD medication use by pupils are mainly ambivalent, but more positive than negative effects of medication are reported. However, what teachers say about ADHD medication is often not based on sound information; their attitudes tend to be formed by personal experiences rather than founded on professional and scientific sources. We conclude from our analysis that it will be in the interest of reducing the number of children on ADHD medication that teachers have good access to verified and up‐to‐date information on ADHD and medication so that they are better supported in making evidence‐based pedagogical judgments. 相似文献
140.
George N. Shava 《Africa Education Review》2019,16(2):50-68
This article reports on a study of which the purpose was to understand the role of principals in changing underperforming schools towards sustainable improvement in one circuit area of North-West, South Africa. School principals play a crucial role in guiding schools towards sustainable improvement by shaping a vision of academic success for all learners. Managing teaching is one of the core modules in South Africa’s new national qualification for school principals, and that being the case, principals should play a central role in effecting the educational transformation of all learners. The quality of principals’ leadership is the key factor driving the transformational turnaround and improvement required in schools. They perform a highly complex and dynamic role in enhancing and sustaining school improvement. It was the goal of this qualitative study to explore cultural, structural, and agential challenges faced by principals in their effort to provide for change and improvement in their schools. Six schools were purposefully selected to participate in the study and semi-structured interviews were used to gather data from the principals. The study established that paying attention to cultural, structural and agential factors in schools increases their ability to sustain learner improvement. 相似文献