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   61673篇
  免费   2554篇
  国内免费   18篇
  2020年   614篇
  2019年   815篇
  2018年   1091篇
  2017年   1118篇
  2016年   1188篇
  2015年   873篇
  2014年   1021篇
  2013年   4671篇
  2012年   1884篇
  2011年   2041篇
  2010年   1257篇
  2009年   1251篇
  2008年   1787篇
  2007年   1796篇
  2006年   1670篇
  2005年   1454篇
  2004年   1337篇
  2003年   1267篇
  2002年   1352篇
  2001年   1994篇
  2000年   1976篇
  1999年   1497篇
  1998年   716篇
  1997年   637篇
  1996年   626篇
  1993年   584篇
  1992年   1253篇
  1991年   1153篇
  1990年   1138篇
  1989年   1031篇
  1988年   1020篇
  1987年   971篇
  1986年   1051篇
  1985年   1059篇
  1984年   892篇
  1983年   805篇
  1982年   572篇
  1981年   564篇
  1979年   944篇
  1978年   671篇
  1975年   764篇
  1974年   817篇
  1973年   913篇
  1972年   772篇
  1971年   723篇
  1970年   642篇
  1969年   668篇
  1968年   858篇
  1967年   777篇
  1966年   651篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
131.
An eye-tracking experiment investigated whether incremental interpretation applies to interclausal relationships. According to Millis and Just's (1994) delayed-integration hypothesis, interclausal relationships are not computed until the end of the second clause, because the processor needs to have two full propositions before integration can occur. We investigated the processing of causal and diagnostic sentences (Sweetser, 1990; Tversky & Kahneman, 1982) that contained the connective because . Previous research (Traxler, Sanford, Aked, & Moxey, 1997) has demonstrated that readers have greater difficulty processing diagnostic sentences than causal sentences. Our results indicated that difficulty processing diagnostic sentences occurred well before the end of the second clause. Thus comprehenders appear to compute interclausal relationships incrementally.  相似文献   
132.
133.
134.
135.
136.
137.
138.
Visual acuity for the detection of gratings at four orientations was measured for groups of ten boys and ten girls aged five to seven years, from the following four populations: Scots in Glasgow, Pakistanis in Glasgow, Gaels in Stornoway (Outer Hebrides) and East Anglians in Littleport (Cambridgeshire fenlands). The Glaswegians, both Scottish and Pakistani, showed the normal pattern of anisotropy, with poorest acuity for oblique orientations; the East Anglians showed no significant anisotropy; while the Gaels were unusual in showing poorest horizontal acuity. A group of fourteen Pakistani children in Stornoway differed slightly from a matched group of Gaels. The group differences bore little relation to the visual environments, and were probably due to genetic or cultural factors. The relatively poor horizontal acuity of the Gaels was not correlated with astigmatism. Sex differences were also found, with the boys showing higher mean acuity and a higher ratio between vertical and oblique acuity.  相似文献   
139.
The purpose of this study was to determine the effects of Type A behavior and family history of hypertension on cardiovascular reactivity to mental stress in a group of employed black women. Measures of heart rate and of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were taken at rest, during a mental arithmetic task, and during the Type A Structured Interview (SI). Results indicated that the Type A behavior pattern was associated with SBP and DBP hyperresponsivity during the SI but not during mental arithmetic. Additionally, certain speech components of the Type A pattern, as well as features of the potential-for-hostility component, were also related to cardiovascular responses during the SI. Family history of hypertension did not influence the cardiovascular parameters either alone or in combination with Type A behavior. The results suggest that many of the cardiovascular response characteristics of the Type A pattern that have been observed in predominantly white samples also hold true for blacks. Replication of these findings with other subgroups of blacks, such as young females and middle-aged males, will help document the generality of these findings within the black population.  相似文献   
140.
Three experiments used a discriminated operant procedure to study conditional discrimination learning in rats. The first experiment showed that rats were capable of learning a biconditional discrimination in which two contexts served as conditional cues signalling the reinforcement contingencies associated with two discriminative stimuli. The discrimination was learned equally well when one discriminative stimulus signalled food, the other its absence, and when one stimulus signalled food, the other extinction plus mild footshock.

In Experiment 2 it was shown that prior training on such a conditional discrimination enhanced the subsequent context specificity of simple conditioning relative to control groups of animals for whom the prior training had not been conditional. Experiment 3 showed that a reversal of the significance of one pair of discriminative stimuli produced no spontaneous reversal in performance to a second, target, pair.

The pattern of results is best accounted for by an analysis of contextual conditional discrimination learning in terms of stimulus configurations and offers no support for the notion that rats may learn a general conditional rule or set.  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