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   177746篇
  免费   7852篇
  国内免费   164篇
  2021年   1519篇
  2020年   2809篇
  2019年   3486篇
  2018年   3650篇
  2017年   4075篇
  2016年   4720篇
  2015年   3952篇
  2014年   4839篇
  2013年   23581篇
  2012年   4850篇
  2011年   3974篇
  2010年   4051篇
  2009年   4843篇
  2008年   4148篇
  2007年   3731篇
  2006年   4262篇
  2005年   4203篇
  2004年   3671篇
  2003年   3307篇
  2002年   3135篇
  2001年   3429篇
  2000年   3256篇
  1999年   3240篇
  1998年   2835篇
  1997年   2672篇
  1996年   2578篇
  1995年   2448篇
  1994年   2394篇
  1993年   2351篇
  1992年   2705篇
  1991年   2506篇
  1990年   2405篇
  1989年   2282篇
  1988年   2262篇
  1987年   2278篇
  1986年   2247篇
  1985年   2429篇
  1984年   2555篇
  1983年   2346篇
  1982年   2379篇
  1981年   2345篇
  1980年   2199篇
  1979年   2274篇
  1978年   2206篇
  1977年   2155篇
  1976年   1966篇
  1975年   2049篇
  1974年   2094篇
  1973年   1998篇
  1972年   1543篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Fear of Success (FOS) was originally conceived as a unidimensional motive. However, there is both theoretical and empirical support for the hypothesis that FOS is multidimensional. We factor analyzed the responses of 236 undergraduates to twenty-oneConcern Over the Negative Consequences of Success items and found four factors. Our four factors show considerable overlap with dimensions based on theoretical accounts of FOS etiology as well as with the factor structures obtained from two other factor analytic studies. Thus, there is converging evidence that FOS is multidimensional. The relationship between multidimensional FOS and a multidimensional approach to achievement motivation is discussed.  相似文献   
912.
913.
914.
915.
916.
The purpose of this study was to document the responses of pharmacy students and pharmacists to various ethical dilemmas. The responses of the first professional year students, third professional year students and pharmacists were evaluated and compared. In most instances, responses indicated a high priority for patient/client welfare. Pharmacists and students reportedly act with regard to the dignity of life, individual freedom, and an inner sense of right.  相似文献   
917.
918.
Pigeons were trained to acquire a new four-response position sequence each day by pecking three response keys in a predetermined order. The key color varied after each correct response prior to food delivery. Acute administration of Γ9-tetrahydrocannabinol (Δ9-THC) up to a dose that completely eliminated responding, had no effect on total acquisition errors, or on within session patterns of error elimination. Chronic administration of Δ9-THC (3–10 mg/kg/day), either before or after the session for 4–7 weeks, also did not affect these error measures, although rates of responding were markedly suppressed and at times no responding occurred Discontinuation of Δ9-THC administration for periods of 4–6 weeks also was without effect on errors. These experiments suggest that neither acute nor chronic Δ9-THC produce specific effects on the repeated acquisition of serial position responses in pigeons.  相似文献   
919.
Experiment 1 elicited the P1, N1, P2, and N2 components of the long latency auditory evoked potential (AEP) using a 1000 Hz tone presented at 30, 50, or 70 dB SPL and 1-, 3-, or 5- second inter-stimulus intervals to assess the relative effects of the combination of these variables on component amplitude and latency. Four blocks of 16 tone presentations each were recorded from each subject to determine if changes in the AEP would occur because of short-term habituation. Both stimulus factors interacted significantly in a systematic fashion for the amplitude measures, with increases in latency also associated with increases in intensity and inter-stimulus interval. Only minor changes across the four trial blocks for either the amplitude or latency measures were observed over the various stimulus presentation conditions. Experiment 2 employed the same tone stimulus presented at 50 dB SPL and a 3-second inter-stimulus interval. Eight blocks of 64 trials were recorded from each subject on each day for four days to investigate long-term habituation effects. No substantial changes in any of the component amplitudes or latencies were obtained across the 32 trial blocks. It was concluded that intensity and inter-stimulus interval interact to determine AEP amplitude as well as latency values and that the constituent components do not change appreciably with repeated stimulus presentations, even after several days.  相似文献   
920.
The present study outlines a rapid and sensitive on-the-baseline conditional emotional response (CER) procedure. Using rats as the experimental subject, the method detects delay conditioning, incubation, extinction and spontaneous recovery. In addition, the method detects conditional responding using electric shock ranging from 0.23 to 0.50 mA as the unconditional stimulus. Because of its speed and sensitivity, the method shelters the subject from unnecessary long-term deprivation and pain.  相似文献   
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