首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   48233篇
  免费   1248篇
  国内免费   20篇
  2020年   377篇
  2019年   432篇
  2018年   3939篇
  2017年   3289篇
  2016年   2779篇
  2015年   644篇
  2014年   663篇
  2013年   2640篇
  2012年   1585篇
  2011年   3368篇
  2010年   3082篇
  2009年   2104篇
  2008年   2581篇
  2007年   3049篇
  2006年   936篇
  2005年   1058篇
  2004年   936篇
  2003年   862篇
  2002年   828篇
  2001年   940篇
  2000年   926篇
  1999年   680篇
  1998年   383篇
  1997年   387篇
  1996年   355篇
  1995年   298篇
  1994年   285篇
  1993年   268篇
  1992年   498篇
  1991年   489篇
  1990年   492篇
  1989年   417篇
  1988年   373篇
  1987年   393篇
  1986年   379篇
  1985年   410篇
  1984年   391篇
  1983年   337篇
  1982年   279篇
  1981年   266篇
  1980年   245篇
  1979年   326篇
  1978年   288篇
  1977年   252篇
  1976年   233篇
  1975年   281篇
  1974年   330篇
  1973年   310篇
  1972年   237篇
  1968年   237篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study investigated the effectiveness of computer-based training (CBT) versus the standard or traditional lecture method. The study was conducted at a large pharmaceutical manufacturing site located in Eastern North Carolina. Subjects were chemical processors in the bulk chemical production division (N=54). All subjects completed a comprehensive hazardous chemicals safety training program, with one treatment group completing the course via a self-directed computer program (n=27) and one completing the course via traditional instructor-led sessions (n=27). Both delivery formats were identical relative to learning objectives and content. Level of learning was assessed via a 33-item pretest and posttest. Subjects were also administered a 33-item retention test one month following completion of the program. Subject biographical data, including educational level, were collected by questionnaire and the Computer Anxiety Index (CAIN) was administered to assess subjects' level of computer anxiety within the CBT group. Satisfaction with training was assessed in both treatment groups. Results indicated 1) both groups demonstrated significant learning following training, 2) there was no significant difference in level of learning between the two groups, 3) retention after one month was significantly higher in the CBT groups, 4) there was no correlation between educational level or computer anxiety and learning, and 5) there was no significant difference between the two groups on satisfaction with the training experience.  相似文献   
992.
In the August 1993 issue ofJournal of Applied Psychology, Deniz Ones, Vish Viswesvaran, and Frank Schmidt published a monograph on the validity of integrity tests as revealed by meta-analysis. They concluded that integrity tests have substantial and generalizable predictive validity for criteria of both overall job performance and counterproductive behaviors on the job (e.g., disciplinary problems, absenteeism, rule breaking, violence on the job, theft, etc.). During the Fall of 1992, the authors sent a preprint of this study to David Lykken of the University of Minnesota, stimulating the exchange of letters that is reproduced here. The doubts, concerns, and feelings about integrity tests expressed by Professor Lykken are likely to be shared by others. The responses by Professors Schmidt, Ones, and Viswesvaran attempt to show that these worries are unfounded.  相似文献   
993.
The Human Genome Project has raised many issues regarding the contributions of genetics to a variety of diseases and societal conditions. With genetic testing now easily conducted with lowered costs in nonmedical domains, a variety of privacy issues must be considered. Such testing will result in the loss of significant privacy rights for the individual. Society must now consider such issues as the ownership of genetic data, confidentiality rights to such information, limits placed on genetic screening, and legislation to control genetic testing and its applications. There is often a conflict between individual rights to privacy and the need for societal protection.  相似文献   
994.
Recent studies have documented the increasing trend among school districts toward adopting full inclusion as the predominant model for serving students who qualify for special education services. Although these data may suggest that a paradigm shift has already taken place and that a consensus of opinion has been achieved, several organizations representing students with specific disabilities continue to support a continuum of placement options. This paper challenges a one size fits all approach to special education, and highlights the importance of considering the individual characteristics of students. The relevance of research on full inclusion, as well as methodological issues that limit generalizability of findings related to student outcomes, are discussed. The radical perspective of full inclusion is rejected in favor of an approach that emphasizes the complexities of placement decisions.  相似文献   
995.
Event-related brain potentials were recorded while disabled adolescent subjects read and judged whether two sequentially presented pictures had names that rhymed. Subjects with relatively good phonetic skills displayed an N400 priming effect, i.e., a significant reduction in the amplitude of the negative peak, occurring approximately 400 msec post-stimulus, for pictures with names that rhymed with preceding pictures as compared with pictures that had names that did not rhyme with the prime. No such effect was evident for subjects with relatively poor phonetic skills. This lack of an N400 priming effect provides evidence for a reduction in neural capacity and/or activation during phonological processing in the subjects with poor phonological skills. Demonstrating the N400 priming effect to be stronger in one group of reading disabled subjects, compared to another, supports the position that specific subtypes of reading disability exist. In addition to the stronger N400 priming effect, the phonetically stronger group also exhibited an enhanced negativity, from 700 to 1,000 msec after target stimulus onset, compared to phonetically inferior subjects. This finding replicates earlier work and possibly reflects a higher level of confidence in the group with better phonetic skills.  相似文献   
996.
Book notes     
Mana: Revue de Sociologie et d'Anthropologie Caen: Department of Sociology, University of Caen, Esplanade de la Paix, 1400 Caen, France. 242 pp, 81 FF (in France, inch postage)

Desh Pardesh: The South Asian Presence in Britain Roger Ballard, ed., 1994 London: Hurst & Co. 296 pp., £9.95 (pb) ISBN 1–85065–092–6

Religions et sécurité international Jean‐François Mayer, 1995 Bern: Office Central de la Défense Series: Études relatives à la politique de sécurité, No. 2/1995 143 pp.

Essential Teachings His Holiness the Dalai Lama London: Souvenir Press, 1995 152 pp., £9.99 (hb) ISBN 0–285–63273–6

Voices of Islam John Bowker, 1995 Oxford: Oneworld Publications 188 pp., £8.95 ISBN 1–85168–095–0

A Short History of the Bahá'i Faith Peter Smith, 1996 Oxford: Oneworld Publications 168 pp., £5.95 (pb) ISBN 1–85168–070–5

A Short History of Islam William Montgomery Watt, 1996 Oxford: Oneworld Publications 156 pp., £5.95 (pb) ISBN 1–85168–109–4

Dictionary of the Middle East Dilip Hiro, 1996 Basingstoke: Macmillan 367 pp., £14.99 (pb) ISBN 0–333–65926–0

The Hebrew Bible Dan Cohn‐Sherbok, 1996 London: Cassell 257 pp., £55.00 (hb), £13.99 (pb) ISBN 0–304–33702–1 (hb), 0–304–33703‐X (pb)

The Puzzle of God Peter Vardy, 1995 London: Fount/Harper Collins 240 pp., £7.99 ISBN 0–00–627965–1  相似文献   

997.
The use of “process-tracing” techniques for examining individuals’ decision strategies has been criticized widely for yielding results that are uninformative and often confounded. The present paper describes a new technique based on a “structural” approach that allows efficient assessment of finely discriminated decision strategies via a HyperCard program called DECOUT. The program presents individuals with an information matrix (e.g., describing five alternative pesticides on three attributes). Individuals are asked to choose the best or the worst alternative in the matrix for 12 problems. Information in the matrix is constructed so that choice of an alternative by an individual is uniquely associated with use of one particular decision strategy. The strategies include information integration, maximin, maximax, pessimism-optimism, and minimax-regret processes. An experiment using the program is described, and possible directions for future research and development are discussed.  相似文献   
998.
999.
Congenital bilateral absence of the vas deferens (CBAVD) occurs in approximately 1.3% of infertile males and is thought to be, in most cases, a primarily genital form of cystic fibrosis (CF). Fourteen males with CBAVD considering microsurgical sperm aspiration from the epididymis (MESA) and in vitro fertilization were seen for genetic counseling and screening for CF. To retrospectively evaluate these patients' perceptions of the counseling and screening information, we conducted structured telephone interviews to assess their recall of information about CF and its impact on their health concerns and reproductive plans. We found that, as the health implications of CF are abstract and not as important to patients as the diagnosis of CBAVD itself, patients tend to view their CF status primarily in terms of their reproductive potential. Retrospective analysis afforded us an opportunity to identify the psychosocial issues of most concern to this unique patient population.  相似文献   
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号