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   2257篇
  免费   75篇
  国内免费   2篇
  2023年   17篇
  2021年   27篇
  2020年   31篇
  2019年   48篇
  2018年   54篇
  2017年   66篇
  2016年   76篇
  2015年   43篇
  2014年   57篇
  2013年   307篇
  2012年   88篇
  2011年   95篇
  2010年   58篇
  2009年   56篇
  2008年   65篇
  2007年   84篇
  2006年   66篇
  2005年   63篇
  2004年   57篇
  2003年   53篇
  2002年   69篇
  2001年   37篇
  2000年   59篇
  1999年   38篇
  1998年   20篇
  1997年   27篇
  1996年   17篇
  1995年   22篇
  1994年   22篇
  1993年   27篇
  1992年   23篇
  1991年   20篇
  1990年   17篇
  1989年   21篇
  1988年   22篇
  1987年   29篇
  1986年   28篇
  1985年   31篇
  1984年   22篇
  1983年   18篇
  1982年   21篇
  1981年   28篇
  1980年   24篇
  1979年   26篇
  1978年   22篇
  1977年   16篇
  1976年   18篇
  1975年   19篇
  1974年   29篇
  1973年   26篇
排序方式: 共有2334条查询结果,搜索用时 31 毫秒
941.
The brain peptide, vasopressin (VP), was studied with respect to its effects on maternal care in rearing natural and cross-fostered pups. Long-Evans (LE) rats synthesize hypothalamic VP; whereas, Brattleboro (DI) rats do not produce this peptide. Long-Evans dams exhibited superior maternal care when compared with DI dams when rearing their own as well as foster pups. This enhanced behavior was evidenced by the higher survival rate of pups reared by LE mothers compared to those reared by DI mothers. Later, when the offspring were subjected to the stress of 23 hours of food restriction each day, LE animals reared by their natural mothers survived for a significantly longer period of time and developed significantly less stomach pathology than DI animals reared by their natural mothers or LE foster mothers. The results demonstrated that the secondary factor of maternal care in the absence of VP was of little consequence in the characteristic difficulties observed in DI offspring.  相似文献   
942.
The brain peptide, vasopressin (VP), was studied with respect to its effects on maternal care in rearing natural and cross-fostered pups. Long-Evans (LE) rats synthesize hypothalamic VP; whereas, Brattleboro (DI) rats do not produce this peptide. Long-Evans dams exhibited superior maternal care when compared with DI dams when rearing their own as well as foster pups. This enhanced behavior was evidenced by the higher survival rate of pups reared by LE mothers compared to those reared by DI mothers. Later, when the offspring were subjected to the stress of 23 hours of food restriction each day, LE animals reared by their natural mothers survived for a significantly longer period of time and developed significantly less stomach pathology than DI animals reared by their natural mothers or LE foster mothers. The results demonstrated that the secondary factor of maternal care in the absence of VP was of little consequence in the characteristic difficulties observed in DI offspring.  相似文献   
943.
944.
This research compares the relative effectiveness of imported and indigenous measures of personality perception for Hong Kong Chinese. The first study reports on the extraction of six factors of self-perception using bipolar, adjective rating scales from the U.S.A. tapping the Big Five (Digman, 1990), and Openness to Experience (McCrae & Costa, 1985; 1987). The second study reports on the extraction of six factors of self-perception derived from scales developed indigenously by Chinese psychologists. In the third study, the overlap of the imported and the indigenous dimensions is examined, and their relative power in explaining various criterion measures is assessed. The imported factors adequately explained all but one of the indigenous factors, although in complex combinations. Neither scale was better than the other in predicting the criterion variables. Imported measures may cut the phenomenal world differently from indigenous measures, but still enable scientists to predict behaviours just as effectively. In consequence, if replicated with other criterion variables, the present results would challenge the investment required to develop local instrumentation on scientific grounds.  相似文献   
945.
946.
Summary This paper explores age-related performance variability, both within trials and between sessions, in repetitive hopping. The mean, the standard deviation (SD), and the coefficient of variation (CV) of several timing and ground-reaction-force variables of hopping were analysed by repeated-measures ANOVA for age-related effects across test sessions and foot used. Forty-five subjects in five age groups (3–4 years, 4–5 years, 6–7 years, 8–9 years, or Adult) performed self-paced, one-footed hopping on three occasions within one week. As was expected, the results showed main effects for Age in all force and time variables, with the exception of CV of medio-lateral force. No significant main effects for Feet were revealed. However, significant Feet x Session interactions were found in flight-time measures, with higher flight-time SD and lower CV for the non-preferred foot in Session 1, a reversal in Session 2, and a negligible difference in Session 3. Across sessions, decreased SD and CV for both vertical and medio-lateral force and shorter flight time indicated more efficient hopping. Overall, it was concluded that SD and CV measures were more sensitive measures of children's performance across repeated sessions than were mean scores and that the order of testing the limbs is an important consideration in experimental protocols when lateralized tasks are measured.  相似文献   
947.
This research explores the work perceptions, both physical and mental, of women. The research finds that women's perceptions of waged and nonwaged labor differ greatly depending on the work environment. Perceptions of physical demands of waged labor are almost solely dependent on the type of paid labor women engage in. For homeworkers, perceptions of physical labor are influenced primarily by the number of hours invested in housework. The mental demands of waged and nonwaged labor are also perceived differently. Women in the waged economy report significantly higher mental demands than do homeworkers. This too varies across labor segments. The closest parallel between physical and mental demand perceptions is between homeworkers and women in the service sector of the waged economy. Overall the assumption that women perceive their work roles in the waged market and the home market similarly is negated.  相似文献   
948.
Factors influencing the selection and purchase of toys for children's use were investigated. Subjects were 73 parents or adult friends of normally developing or handicapped preschool children. In addition to providing demographic information about themselves, the subjects rated the importance of 17 factors influencing their selection and purchase of toys. Contrary to previous research, the sex of the child was reported to be of only minor importance in toy selection, as was the picture on the toy package. Two factors, safety and teaching new skills, were rated as extremely important. There were no significant differences in ratings as a result of sex, ethnicity, or whether or not the subjects were parents of a handicapped child. The findings suggest a substantial degree of agreement among parents about what they consider important when choosing toys for children.  相似文献   
949.
The purpose of the present study was to determine if lingual vibrotactile threshold shifts occurred during magnitude-estimation scaling of suprathreshold stimuli presented to the dorsal surface of the tongue. Possible relationships of the lingual vibrotactile threshold shifts to suprathreshold stimulus intensity, magnitude-estimation responses, and overall scaling behavior were explored. A single group of 24 subjects with an age range of 18 to 22 years participated in this study. Each subject performed two magnitude-estimation tasks. In one of the tasks, threshold of sensitivity was determined after every suprathreshold numerical response of the subject. If a threshold shift was recorded, threshold was allowed to return to the pretest baseline level before continuing to the next suprathreshold stimulus presentation. The results showed that threshold shift did occur during lingual vibrotactile magnitude-estimation scaling, and that it was related to suprathreshold stimulus intensity. The results also showed that the numerical magnitude-estimation responses of the subjects were different for the two scaling tasks. Overall scaling behavior of the subjects in the form of power-function exponents was not different for the two tasks.  相似文献   
950.
Problems with clinical research that create conflicts between doctors’ therapeutic and research obligations may be fueled by a rigid view of science as determiner of truth, a heavy reliance on statistics, and certain features of randomized clinical trials. 1 suggest some creative, feminist approaches to such research and explore ways to provide choice for patients and to use values in directing both therapy and science — to enhance the effectiveness of each.  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