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   15426篇
  免费   682篇
  国内免费   7篇
  2020年   169篇
  2019年   172篇
  2018年   265篇
  2017年   235篇
  2016年   272篇
  2015年   208篇
  2014年   261篇
  2013年   1097篇
  2012年   477篇
  2011年   435篇
  2010年   303篇
  2009年   277篇
  2008年   401篇
  2007年   421篇
  2006年   366篇
  2005年   360篇
  2004年   312篇
  2003年   273篇
  2002年   301篇
  2001年   674篇
  2000年   666篇
  1999年   453篇
  1998年   169篇
  1997年   164篇
  1996年   162篇
  1995年   136篇
  1992年   361篇
  1991年   341篇
  1990年   353篇
  1989年   301篇
  1988年   286篇
  1987年   281篇
  1986年   256篇
  1985年   257篇
  1984年   238篇
  1983年   203篇
  1982年   156篇
  1979年   220篇
  1978年   172篇
  1977年   148篇
  1975年   190篇
  1974年   230篇
  1973年   229篇
  1972年   183篇
  1971年   180篇
  1970年   148篇
  1969年   176篇
  1968年   210篇
  1967年   191篇
  1966年   156篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
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   
202.
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   
203.
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   
204.
Three experiments were conducted with adult male Meriones unguiculatus in an attempt to demonstrate that ventral scent marking can act to transfer body heat to the object marked. Experiment 1 showed that surgical removal of the ventral gland pad reduced the amount of heat transferred by 50%, even though intact and glandless animals did not differ in the average frequency of scent marking. Experiment 2 demonstrated that the difference in heat transfer due to the presence or absence of the scent pad was not due to differential pressure applied to the substrate during marking. Experiment 3 showed that the pattern of ventral hair spread that occurs as an animal moves over an object is different between intact and glandless animals but that this difference does not account for the difference in heat transfer. It is suggested that heat transfer to the environment with ventral scent marking may increase thermoregulatory competence and also may function to volatilize sebum used in chemocommunication.  相似文献   
205.
Previous findings indicate that Norway rats (Rattus norvegicus) respond differentially to estrous chemostimuli in early infancy and that adult male sexual responsiveness to such chemostimuli depends on infantile experience with suckling odors (Fillion & Blass, in press). The development of behavioral responsiveness to estrous chemostimuli in male rats from late infancy to adulthood was examined in this study. Preweanling, adolescent, and adult males were observed for 20 min in the presence of an anesthetized estrous or an anesthetized diestrous female. This was, for adolescent and adult subjects, the first heterosexual encounter since weaning. Rats in each age-group responded differentially according to female state, but in distinct, age-related ways. Preweanling spent more time investigating the female's body if she was estrous. Adults expressed the same affinity but by more focused investigation directed perivaginally. Adolescents showed no female-directed bias but groomed themselves more if the female was estrous. These data identify developmental continuities and discontinuities in male rat behavior toward sexually receptive females.  相似文献   
206.
T Aarkrog 《Adolescence》1985,20(79):682-687
This study investigated the parents of 100 psychotic and borderline adolescents, and their relationships with their adolescent children. The incidence of psychiatric disorders among the parents, and the incidence of one-parent homes, as well as the divorce rate of biological parents, are given. A direct assessment of the number of pathological relationships between adolescents and parents, defined from a therapeutic point of view, was also made. Examples are given of parental pathology or marital discord concealed in the adolescents' pathology, or in the parent-adolescent relationship. It was concluded that the assessment of parents and their relationships with the adolescents is important for the treatment of the adolescent.  相似文献   
207.
208.
Memory for events occurring under anesthesia   总被引:1,自引:0,他引:1  
  相似文献   
209.
210.
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