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   66410篇
  免费   2634篇
  国内免费   31篇
  2020年   643篇
  2019年   803篇
  2018年   1096篇
  2017年   1151篇
  2016年   1179篇
  2015年   891篇
  2014年   1010篇
  2013年   4847篇
  2012年   1865篇
  2011年   1954篇
  2010年   1251篇
  2009年   1213篇
  2008年   1763篇
  2007年   1688篇
  2006年   1510篇
  2005年   1379篇
  2004年   1273篇
  2003年   1264篇
  2002年   1215篇
  2001年   2204篇
  2000年   2146篇
  1999年   1582篇
  1998年   728篇
  1996年   612篇
  1992年   1431篇
  1991年   1351篇
  1990年   1351篇
  1989年   1195篇
  1988年   1183篇
  1987年   1153篇
  1986年   1147篇
  1985年   1267篇
  1984年   1015篇
  1983年   862篇
  1982年   639篇
  1981年   623篇
  1979年   1074篇
  1978年   727篇
  1977年   708篇
  1976年   668篇
  1975年   937篇
  1974年   1009篇
  1973年   1106篇
  1972年   930篇
  1971年   834篇
  1970年   829篇
  1969年   834篇
  1968年   1067篇
  1967年   932篇
  1966年   908篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
851.
In an earlier study, we found that men who smoked a cigarette and then engaged in a mildly stressful activity (video game) evidenced pronounced increases in heart rate and blood pressure, which were approximately equal to the sum of the effects produced by either smoking alone or stress alone. In the present study, a 2 (smoke vs. sham smoke) X 2 (stress vs. no stress) factorial design was used to evaluate the impact of stress and smoking on the cardiovascular responses of young women. The results revealed that the combination of stress and cigarette smoking produced blood pressure and heart rate responses that were larger than the additive effects of smoking and stress taken separately.  相似文献   
852.
Previous studies have examined intra-individual aggregation in the use of cigarettes, alcohol, and coffee by examining the co-occurrent use of any pair of these three substances. A recent literature review failed to find a single investigation that studied use of all three in the same sample. In the present study, co-occurrent use of all three of these substances was examined in crossvalidated subsamples of 226 male and 245 female healthy, community-living, middle-class Americans. A log-linear analysis was used to compare the proportion of smokers, ex-smokers, and nonsmokers categorized as users of more or less amounts of coffee and alcohol. Although most of the intercorrelations were not strong, the results indicate that for both sexes, smokers and ex-smokers were more likely than nonsmokers to drink greater amounts of alcohol and coffee. Furthermore, for smokers, ex-smokers, and nonsmokers, a majority of individuals who reported drinking more alcohol also reported drinking more coffee. Interestingly, the coffee and alcohol consumption levels of ex-smokers resembled those of smokers more than those of nonsmokers. Also, ex-smokers reported drinking more wine and decaffeinated coffee than either smokers or nonsmokers. Finally, the number of cigarettes smoked per day (daily quantity) was positively related to total alcohol and coffee consumption in men, but not in women. Further studies are recommended to examine the role of individual differences in the development, maintenance, and modification of these three appetitive habits and their co-occurrence.  相似文献   
853.
Studies with clinical populations have shown a high level of neuroticism amongst those with an eating disorder. It is unclear however whether the elevated neuroticism is a function of the disorder, or if it is an aetiological factor in the disorder's development. The present survey of a non-clinical female population revealed that those high in neuroticism gave higher—but not abnormally high—scores on a measure of concern about eating. The high-N group also reported a significantly greater number of undesirable life events; a greater familiarity with ‘diet literature’; increased dieting; but no difference in body weight from those in the middle and lower ranges on the N scale. On the basis of these findings it is suggested that neuroticism is an aetiological factor in disordered eating, at least with secondary if not primary disorders. It is propesed that neuroticism is one mediating psychological factor in a triadic relationship between personal environment contingencies, socio-cultural pressures for thinness and psychological variables. Suggestions are made for future investigation of the role of neuroticism in eating disturbance, with note of potential therapeutic application of such knowledge.  相似文献   
854.
Food-deprived Drosophila melanogaster extend their proboscises following sucrose stimulation of the front tarsi (the proboscis extension reflex). Médioni and Vaysse (1975) reported that the inhibition of this response can be conditioned over trials if such proboscis extensions are punished by applying an aversive stimulus to the foreleg tarsi. In this study, Médioni and Vaysse's basic observations of conditioning were replicated, with a different strain of flies and a modified conditioning apparatus.  相似文献   
855.
Two adult male chimpanzees reached through a hole in the wall of their home cage and, by tracking the images of their hands and of an otherwise hidden target object in a mirror or closed-circuit television picture, moved their hands in whichever direction was necessary to make contact with the target object. They discriminated between live video images and tapes and performed effectively when the target objects were presented in novel locations and when the video picture was presented at random in different orientations. There was thus no consistent relation between the location of images on the monitor and the location of their real-world counterparts. Comparable performances in monkeys and nonprimates seem unlikely.  相似文献   
856.
This essay provides guidelines for designing a doctoral program in behavior analysis. First, we propose a general accomplishment for all behavior analytic doctoral students: that they be able to solve problems concerning individual behavior within a range of environments. Second, in order to achieve this goal, we propose that students be trained in conceptual and experimental analysis of behavior, the application of behavioral principles and the administration of behavioral programs. This training should include class work, but it should emphasize the immersion of students in a variety of environments in which they are required to use behavior analytic strategies. Third, we provide an example of a hypothetical graduate program that involves the proposed training. Finally, an evaluation plan is suggested for determining whether a training program is in fact producing students who are generalized problem-solvers. At each step, we justify our point of view from a perspective that combines principles from behavior analysis and educational systems design.  相似文献   
857.
858.
In this paper, I describe a computer program, WORDPRO, which simulates the psychological processes involved when third-grade children understand and solve simple arithmetic word problems. Both the implementation of the program and its performance on a set of sample problems are presented. WORDPRO is a useful research tool in that it demonstrates the sufficiency of the theory upon which it is based, assists in communicating that theory to other researchers, and provides a sources of empirical predictions for experimental tests of the theory.  相似文献   
859.
860.
Sternheim and Boynton’s (1966) continuous judgmental color-naming technique was used to assess the elemental nature of achromatic colors. Results from three subjects indicate that the names “black” and “white” are necessary and sufficient to describe achromatic test lights associated with the name “gray.” On the basis of the criteria that establishes a color as elemental, black and white were confirmed as elemental, whereas gray was not. These findings support the assumption of various opponent processing models that there are only two elemental achromatic sensations. In addition, the results support Hering’s (1920) view that black and white differ from the paired-chromatic opponent colors in that they are not mutually exclusive.  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