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   43392篇
  免费   1676篇
  国内免费   20篇
  2020年   421篇
  2019年   567篇
  2018年   777篇
  2017年   846篇
  2016年   809篇
  2015年   614篇
  2014年   724篇
  2013年   3784篇
  2012年   1262篇
  2011年   1412篇
  2010年   918篇
  2009年   925篇
  2008年   1317篇
  2007年   1209篇
  2006年   1155篇
  2005年   1034篇
  2004年   998篇
  2003年   1013篇
  2002年   985篇
  2001年   1400篇
  2000年   1335篇
  1999年   1020篇
  1998年   564篇
  1997年   488篇
  1996年   440篇
  1995年   458篇
  1994年   449篇
  1993年   453篇
  1992年   872篇
  1991年   816篇
  1990年   798篇
  1989年   730篇
  1988年   692篇
  1987年   702篇
  1986年   656篇
  1985年   738篇
  1984年   647篇
  1983年   545篇
  1982年   475篇
  1981年   455篇
  1979年   584篇
  1978年   515篇
  1977年   477篇
  1976年   459篇
  1975年   545篇
  1974年   565篇
  1973年   574篇
  1972年   452篇
  1968年   446篇
  1966年   440篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
Three experiments, each using a single group of pigeons, are reported. In Experiment 1 subjects were initially trained with two stimuli, one of which was always followed by food, the other being reinforced according to a 50% partial reinforcement schedule. Subsequently a serial procedure was adopted in which an additional stimulus, C, was consistently followed by the partially reinforced CS. A second additional stimulus, A, was followed on half of its occurrences by the continuously reinforced CS, its remaining presentations being followed by nothing. The rate of autoshaped keypecking was substantially greater during A than during C. In the remaining experiments subjects received first-order conditioning with a single stimulus that was either partially (Experiment 2) or continuously (Experiment 3) reinforced. The stimuli A and C were then again introduced for serial autoshaping. Stimulus A was occasionally paired with the CS and occasionally followed by nothing, whereas stimulus C was always followed by the CS. As in Experiment 1, the rate of responding during A was greater than during C. It is proposed that one influence on the rate of autoshaped keypecking during a CS is the accuracy with which the immediate consequences of that CS are predicted.  相似文献   
43.
44.
The three reliability and two construct validity studies presented here represent the first psychometric research on the commercially successful and popular Hartman Color Code Personality Profile. The reliability studies found high reliability after 3 and 6 weeks. The construct validity studies substantiated that the Color Code assesses some personality traits. The magnitude of the error variance suggests caution, however, in using the Color Code classifications at the individual level.  相似文献   
45.
It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement-like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement-like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2-component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement-like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent-chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement-like effects.  相似文献   
46.
47.
48.
Although perceived health risk plays a prominent role in theories of health behavior, its empirical role in risk taking is less clear. In Study 1 (N = 129), 2 measures of drivers' risk-taking behavior were found to be unrelated to self-estimates of accident concern but to be related to self-ratings of driving skill and the perceived thrill of driving. In Study 2 (N = 405), out of a wide range of potential influences, accident concern had the weakest relationship with risk taking. The authors concluded that although health risk is a key feature in many theories of health behavior and a central focus for researchers and policy makers, it may not be such a prominent factor for those actually taking the risk.  相似文献   
49.
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.  相似文献   
50.
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