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   34409篇
  免费   1228篇
  国内免费   15篇
  35652篇
  2020年   342篇
  2019年   373篇
  2018年   466篇
  2017年   551篇
  2016年   598篇
  2015年   574篇
  2014年   613篇
  2013年   2903篇
  2012年   1061篇
  2011年   1052篇
  2010年   755篇
  2009年   782篇
  2008年   984篇
  2007年   893篇
  2006年   791篇
  2005年   758篇
  2004年   713篇
  2003年   667篇
  2002年   672篇
  2001年   793篇
  2000年   787篇
  1999年   569篇
  1998年   337篇
  1992年   571篇
  1991年   553篇
  1990年   539篇
  1989年   545篇
  1988年   491篇
  1987年   487篇
  1986年   515篇
  1985年   563篇
  1984年   496篇
  1983年   440篇
  1982年   366篇
  1981年   410篇
  1980年   342篇
  1979年   526篇
  1978年   401篇
  1977年   392篇
  1976年   363篇
  1975年   500篇
  1974年   538篇
  1973年   544篇
  1972年   442篇
  1971年   427篇
  1970年   392篇
  1969年   414篇
  1968年   511篇
  1967年   488篇
  1966年   459篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
This article aims tt providing some conceptual tools for dealing adequately with relevance in argumentative discourse. For this purpose, argumentative relevance is defined as a functional interactional relation between certain elements in the discourse. In addition to the distinction between interpretive and evaluative relevance that can be traced in the literature, analytic relevance is introduced as an intermediary concept. In order to classify the various problems of relevance arising in interpreting, analyzing and evaluating argumentative discourse, a taxonomy is proposed in which the concept of relevance is differentiated along three co-ordinate dimensions: object, domain and aspect. With the help of this taxonomy, it can be shown that the problems of evaluative relevance with which the standard approach to fallacies cannot satisfactory deal can be more systematically approached within a pragma-dialectical framework. This is demonstrated for the argumentum and hominem, which is erroneously treated as a homogenous type of relevance fallacy in logico-centric analyses, so that cases where this is not justified must be treated as ad hoc exceptions.  相似文献   
192.
193.
194.
195.
196.
197.
The shortening of the QT interval of the electrocardiogram coincident with acceleration of heart rate and vice versa has been accepted for many years as evidence that the action potential duration and hence QT are necessarily dependent on heart rate. Exceptions to this rule have been attributed to the intervention of counteracting autonomic effects. In order to test this assumption, 26 conscious dogs divided into three groups were tested during baroreceptor stimulation by a bolus injection of phenylephrine. Seventeen dogs had been used in earlier studies in which they had undergone an experimental anterior myocardial infarction with apparent full recovery. A group of those dogs underwent beta-adrenergic blockade by intravenous atenolol 30 min prior to the baroreceptor activation. To test the intactness of the baroreceptor responses in the previously infarcted dogs, a third group of nine dogs that had had no prior myocardial infarction was included. All dogs were adapted to the laboratory environment and were not sedated during experiments. Simultaneous recordings of RR, QT interval, and phasic arterial pressure were made in all dogs before and during baroreceptor stimulation. In the normal group, and the previously infarcted group that received no atenolol, baroreceptor stimulation elicited a small (8/msec), but significant prolongation of the QT associated with a nearly 50% reduction in heart rate. The QT interval of the atenolol-treated dogs, although significantly more prolonged before stimulation, remained unchanged during the reflex. The data indicate that withdrawal of ventricular sympathetic tone may prolong the QT interval, thereby confirming the role of sympathetic innervation in the control of QT.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
198.
A number of investigators have suggested that affective states influence the focus of attention. One recent proposal is that negative moods increase self-focus. This review considers the evidence that bears on this hypothesis. Conceptual issues pertaining to the construct of self-focus are discussed first. Next, the various parameters that influence attentional focus are presented in order to provide a way of organizing the mood/selffocus literature. Studies that have used state measures of mood and self-focus are considered in this context. Methodological limitations of existing studies are discussed and directions for future work provided.  相似文献   
199.
Two dogs received a single paired classical conditioning trial, with tone CS and 12 mA shock US. Both dogs then showed a conditioned blood pressure increase in response to the nonreinforced CS, which extinguished with additional nonreinforced presentations. The CR showed spontaneous recovery four days later, but reextinguished with additional nonreinforced presentations. The results were interpreted as not supporting Eysenck's theory of "incubation" following one-trial aversive conditioning.  相似文献   
200.
A running-wheel movement-detection method is described for use with a modified 1350 Commodore mouse and a Commodore 64, is described. The movement-detection method allows for the detection of partial revolutions and direction of movement, but requires no interface equipment. The modified running wheel is discussed as a new technique that may be useful for bridging empirical and theoretical differences between free-operant and discrete-trial runway procedures.  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