全文获取类型
收费全文 | 9418篇 |
免费 | 100篇 |
国内免费 | 18篇 |
专业分类
教育 | 6342篇 |
科学研究 | 1049篇 |
各国文化 | 91篇 |
体育 | 1015篇 |
综合类 | 6篇 |
文化理论 | 99篇 |
信息传播 | 934篇 |
出版年
2021年 | 71篇 |
2020年 | 127篇 |
2019年 | 177篇 |
2018年 | 243篇 |
2017年 | 258篇 |
2016年 | 222篇 |
2015年 | 161篇 |
2014年 | 219篇 |
2013年 | 1714篇 |
2012年 | 206篇 |
2011年 | 203篇 |
2010年 | 178篇 |
2009年 | 156篇 |
2008年 | 176篇 |
2007年 | 199篇 |
2006年 | 163篇 |
2005年 | 154篇 |
2004年 | 147篇 |
2003年 | 169篇 |
2002年 | 141篇 |
2001年 | 157篇 |
2000年 | 159篇 |
1999年 | 157篇 |
1998年 | 72篇 |
1997年 | 74篇 |
1996年 | 112篇 |
1995年 | 77篇 |
1994年 | 95篇 |
1993年 | 87篇 |
1992年 | 154篇 |
1991年 | 147篇 |
1990年 | 138篇 |
1989年 | 136篇 |
1988年 | 114篇 |
1987年 | 116篇 |
1986年 | 138篇 |
1985年 | 134篇 |
1984年 | 107篇 |
1983年 | 129篇 |
1982年 | 110篇 |
1981年 | 104篇 |
1980年 | 93篇 |
1979年 | 165篇 |
1978年 | 110篇 |
1977年 | 109篇 |
1976年 | 104篇 |
1975年 | 79篇 |
1974年 | 89篇 |
1972年 | 70篇 |
1971年 | 70篇 |
排序方式: 共有9536条查询结果,搜索用时 0 毫秒
131.
The proposed development of extended schools in England is part of an international movement towards community‐oriented schooling, particularly in areas of disadvantage. Although on the face of it this movement seems like a common‐sense approach to self‐evident needs, the evaluation evidence on such schools is inconclusive. In order to assess the likelihood that community‐oriented schooling will have a significant impact on disadvantage, therefore, this paper analyses the rationale on which this approach to schooling appears to be based. It argues that community‐oriented schools as currently conceptualised have a focus on ‘proximal’ rather than ‘distal’ factors in disadvantage, underpinned by a model of social in/exclusion which draws attention away from underlying causes. They are, therefore, likely to have only small‐scale, local impacts. The paper suggests that a more wide‐ranging strategy is needed in which educational reform is linked to other forms of social and economic reform and considers the conditions which would be necessary for the emergence of such a strategy. 相似文献
132.
Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors 总被引:1,自引:0,他引:1
SLADE Paul G LI Wang-pei MAYO Stephen SMITH R. Kirkland TAYLOR Erik D 《浙江大学学报(A卷英文版)》2007,8(3):335-342
The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments. 相似文献
133.
Children who observe gesture while learning mathematics perform better than children who do not, when tested immediately after training. How does observing gesture influence learning over time? Children (n = 184, ages = 7–10) were instructed with a videotaped lesson on mathematical equivalence and tested immediately after training and 24 hr later. The lesson either included speech and gesture or only speech. Children who saw gesture performed better overall and performance improved after 24 hr. Children who only heard speech did not improve after the delay. The gesture group also showed stronger transfer to different problem types. These findings suggest that gesture enhances learning of abstract concepts and affects how learning is consolidated over time. 相似文献
134.
T. Malati G. Rajani Kumari B. Yadagiri 《Indian journal of clinical biochemistry : IJCB》2001,16(2):224-233
Ovarian cancer is the fifth leading cause of death in women. The incidence of this malignancy increases in women over the
age of 40. The overall five years survival is less than 30%, as most women present with advanced stage disease. Until recently,
detection of early stage ovarian cancer has been difficult since it is usually nonpalpable and asymptomatic. The definitive
diagnosis of an ovarian mass is a common problem in gynecologic patients with adnexal mass. The routine standard evaluation
for adnexal masses includes patient's history, physical examination, ultrasound and histopathological examination. These parameters
individually or in combination have little predictive value. The accuracy of diagnostic tools are of immense value and great
concern to practicsing Gynecologists and Oncologists. The clinical application of serum concentration of CA 125, AFP and hCG
is of great help not only as diagnostic aid but also in monitoring efficacy of any treatment modality like chemotherapy, radiotherapy
or surgical resection. Additionally, evaluation of tumor marker concentration helps in predicting early biochemical recurrence
and in prognostication in different types of ovarian malignancies. The ability to differentiate a malignant mass from a benign
pelvic mass pretherapeutically could be enhanced optimally by additional use of tumor markers such as cancer antigen CA-125,
alphafetoprotein and human chorionic gonadotrophin in pre-and postmenopausal women. 相似文献
135.
This article introduces a new "real-time" model of classical conditioning that combines attentional, associative, and "flexible" configural mechanisms. In the model, attention to both conditioned (CS) and configural (CN) stimuli are modulated by the novelty detected in the environment. Novelty increases with the unpredicted presence or absence of any CS, unconditioned stimulus (US), or context. Attention regulates the magnitude of the associations CSs and CNs form with other CSs and the US. We incorporate a flexible configural mechanism in which attention to the CN stimuli increases only after the model has unsuccessfully attempted learn input-output combinations with CS-US associations. That is, CSs become associated with the US and other CSs on fewer trials than they do CNs. Because the CSs activate the CNs through unmodifiable connections, a CS can become directly and indirectly (through the CN) associated with the US or other CSs. In order to simulate timing processes, we simply assume that a CS is formed by a temporal spectrum of short-duration CSs that are activated by the nominal CS trace. The model accurately describes 94?% of the basic properties of classical conditioning, using fixed model parameters and simulation values in all simulations. 相似文献
136.
137.
Anthony G. Wilhelm 《The Information Society》2003,19(4):279-286
Bridging the digital divide between information and technology haves and have-nots has waned from the top of the national policy agenda in the United States during a time in which the sunken investments of the 1990s need to be leveraged. A national information network now exists yet this infrastructure--largely hardware--needs to be continually modernized and parlayed with commitments to building human capacity, developing relevant content, and scaling socially beneficial technology applications, such as telemedicine, in order to optimize these initial multi-billion-dollar outlays. This article makes the case that sidestepping public-private initiatives aimed at accelerating digital opportunity is imprudent, given the mounting empirical evidence highlighting the payoffs of information and communications technologies, when properly integrated and applied, especially in enhancing the life chances of underserved Americans. Policy next steps should advance the goals of expanding universal service initiatives, including hastening broadband deployment to homes and learning institutions, and deepening programs which leverage the utility of the existing infrastructure, such as expanding human-capital development, producing relevant content, and innovating socially beneficial technology applications. 相似文献
138.
139.
H.R. Thompson C.E. Deer J.A. Fitzgerald H.G. Kensell B.C. Low R.A. Porter 《高等教育研究与发展》1990,9(1):39-48
The introduction of academic staff appraisal in higher education institutions in Australia will require a considerable expansion in staff development facilities. An important issue will be the relative emphasis to be placed upon central staff development units as against structures at the faculty or departmental level. This case study, conducted at Macquarie University and aimed at improving teaching in higher education, explores the Self‐Appraisal Workshop as one such structure and suggests that it provides a very useful format at the faculty or departmental level because it brings together people teaching similar course units. As a result it is easier to integrate aspects such as curriculum design, assessment policies, academic content and teaching methods, than it is at the central level where staff development workshops usually have a cross‐faculty mix. An evaluation, based upon student ratings of teaching, interviews and staff reflection on the process, suggests that the Self‐Appraisal Workshop is a valuable technique for staff appraisal and development. 相似文献
140.
Ruurd Taconis Lesley G.M. de Putter-Smits Steven Henry Perry J. den Brok Douwe Beijaard 《Educational Research and Evaluation》2013,19(4):383-400
Forming a science-oriented identity is considered a process underlying both interest and achievement in science education. A questionnaire is developed for describing “identities as learners” and evaluating their science orientedness. The instrument (k = 65) focuses on cognitive aspects. An internal coherence of .88 was found. Five subscales were defined that proved interrelated yet distinguishable. A pilot amongst 40 students from Dutch general secondary education showed that preferring science over non-science subjects and relatively high grades for sciences subjects were strongly correlated to science orientedness of the learner identity (rs = .65; p < .001). The results support the reliability and validity of the questionnaire but also point to the importance of identity as a central concept in studying science education. It is concluded that we made a promising step in constructing an instrument for monitoring the development of cognitive aspects of science-oriented identities during (innovative) science education. 相似文献