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   213658篇
  免费   9000篇
  国内免费   162篇
  2020年   2812篇
  2019年   3487篇
  2018年   4034篇
  2017年   4444篇
  2016年   4963篇
  2015年   3953篇
  2014年   4824篇
  2013年   23533篇
  2012年   5961篇
  2011年   5583篇
  2010年   4550篇
  2009年   5099篇
  2008年   5500篇
  2007年   5238篇
  2006年   5342篇
  2005年   5185篇
  2004年   4647篇
  2003年   4200篇
  2002年   4102篇
  2001年   5111篇
  2000年   4919篇
  1999年   4289篇
  1998年   3024篇
  1997年   2813篇
  1996年   2706篇
  1995年   2535篇
  1994年   2506篇
  1993年   2446篇
  1992年   3585篇
  1991年   3388篇
  1990年   3277篇
  1989年   3067篇
  1988年   3057篇
  1987年   2995篇
  1986年   3030篇
  1985年   3245篇
  1984年   3073篇
  1983年   2752篇
  1982年   2575篇
  1981年   2511篇
  1980年   2350篇
  1979年   2929篇
  1978年   2539篇
  1977年   2402篇
  1976年   2234篇
  1975年   2618篇
  1974年   2741篇
  1973年   2685篇
  1972年   2230篇
  1968年   2157篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
The cynomolgus macaque provides a suitable primate model for studying how psychosocial factors contribute to coronary artery atherogenesis. Important interactions with diet, sex, and behaviorally elicited cardiovascular reactivity are described.  相似文献   
882.
This study examined the independent and joint effects of cigarette smoking and caffeine consumption on blood pressure (BP) and heart rate (HR) reactions to stress in male and female college students. Following an initial physiological baseline, participants received one of four experimental treatments (paced smoking, caffeine, smoking plus caffeine, or neither) and had BP and HR measured before, during, and after two stressful tasks. The results revealed that, compared with the control condition, caffeine ingestion enhanced the magnitude of stress-induced systolic BP and HR reactions. Smoking combined additively with stress, and the joint effect of smoking and caffeine was no greater than either taken alone. Males and females were generally similar in their BP and HR responses to smoking, caffeine, and stress. Inconsistencies with previous research and possible physiological mechanisms underlying the observed effects are discussed.  相似文献   
883.
Contextually relevant aspects of meaning   总被引:2,自引:0,他引:2  
A series of six experiments investigated whether inferences about contextually relevant aspects of meaning were encoded into memory during reading. In all the experiments, subjects studied short paragraphs. Then, test sentences were presented that expressed relevant aspects of meaning that had not been explicitly stated in the paragraphs. For example, for a paragraph about searching for the correct color to paint a picture of a tomato, a relevant aspect of meaning would be that tomatoes are red. The test sentences were presented either immediately following the relevant paragraph or after a delay. With immediate testing, it was argued that the facilitation obtained in verification latency could result from processes occurring either when the context was read or when the test sentence was verified. With delayed testing, evidence was found to support the hypothesis that contextually relevant aspects of meaning are incorporated into the memory representation of the paragraph, but such evidence was obtained only when the retrieval environment encouraged the use of newly learned information in the decision process on the test sentence.  相似文献   
884.
Group work as an integral part of counsellor training appears to have been under-utilised. Certainly it is the case that empirical evaluations of such group work appear rarely in guidance and counselling journals. An attempt is made to remedy these deficiencies by reviewing studies relevant to counsellor training and to report on 17 years of research and experience with group work within a counsellor training programme at a New Zealand university.  相似文献   
885.
The vocationally-indecisive individual presents a major counselling problem. The theory and research behind career indecision is discussed and a counselling approach based on identity formation is outlined. Four identity statuses — Identity Achievements, Foreclosures, Identity Diffusions, and Moratoriums — are described and counselling approaches for each are explored.  相似文献   
886.
We explored what kind of information is acquired when amnesic patients are able to exhibit significant retention on tests of cued recall and recognition memory. Amnesic patients and control subjects attempted to learn sets of sentences. Memory for the last word in each sentence was tested after 1 hr in the case of the amnesic patients, or after 1 to 2 weeks in the case of (delayed) control subjects. Amnesic patients and (delayed) control subjects performed at similar levels on tests of cued recall and recognition memory. Amnesic patients were just as confident of their correct answers as were control subjects. However, amnesic patients were no more disadvantaged than control subjects when they were cued indirectly by presenting paraphrases of the original sentences. These findings demonstrate that the residual knowledge retained by amnesic patients can be as flexible, as accessible to indirect cues, and as available to awareness as the knowledge retained by (delayed) control subjects.  相似文献   
887.
Correlates of responses to two potential hazards   总被引:2,自引:0,他引:2  
  相似文献   
888.
889.
890.
In a series of conditions, pigeons chose between 1.5 s and 3 s of access to grain, each preceded by some delay. The delay that preceded the small reinforcer was constant throughout a condition. The delay that preceded the large reinforcer was increased or decreased a number of times each session in order to estimate an "indifference point," a delay at which the subject chose each alternative about equally often. The experiment was designed to determine whether variations in any of four features of this adjusting-delay procedure would systematically alter the estimated indifference points. The four features were the total trial duration, the number of center-key responses necessary to begin a trial, the number of choice trials that preceded each change in the adjusting delay, and step size--the size of each increment and decrement in the delay. Manipulation of the first three features had no systematic effects on the indifference points. As step size was increased from 0.5 s to 6 s, within-session variability of the adjusting delay steadily increased, and the 6-s step size produced larger indifference-point estimates for some subjects. The results suggest that, within certain limits, these procedural features can be altered without affecting the indifference-point estimates, but that the use of a large step size can distort the estimates. Some theoretical implications of the relative constancy of indifference points across these procedural variations are discussed.  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