全文获取类型
收费全文 | 42583篇 |
免费 | 1623篇 |
国内免费 | 22篇 |
出版年
2020年 | 450篇 |
2019年 | 449篇 |
2018年 | 735篇 |
2017年 | 708篇 |
2016年 | 734篇 |
2015年 | 481篇 |
2014年 | 670篇 |
2013年 | 3162篇 |
2012年 | 1211篇 |
2011年 | 1315篇 |
2010年 | 768篇 |
2009年 | 808篇 |
2008年 | 1125篇 |
2007年 | 1108篇 |
2006年 | 1047篇 |
2005年 | 920篇 |
2004年 | 880篇 |
2003年 | 836篇 |
2002年 | 839篇 |
2001年 | 1440篇 |
2000年 | 1423篇 |
1999年 | 1077篇 |
1998年 | 480篇 |
1997年 | 420篇 |
1992年 | 882篇 |
1991年 | 785篇 |
1990年 | 869篇 |
1989年 | 772篇 |
1988年 | 731篇 |
1987年 | 717篇 |
1986年 | 751篇 |
1985年 | 820篇 |
1984年 | 627篇 |
1983年 | 558篇 |
1982年 | 433篇 |
1981年 | 388篇 |
1979年 | 672篇 |
1978年 | 510篇 |
1977年 | 437篇 |
1976年 | 411篇 |
1975年 | 614篇 |
1974年 | 692篇 |
1973年 | 675篇 |
1972年 | 571篇 |
1971年 | 513篇 |
1970年 | 443篇 |
1969年 | 526篇 |
1968年 | 619篇 |
1967年 | 544篇 |
1966年 | 566篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
S R Hursh T G Raslear D Shurtleff R Bauman L Simmons 《Journal of the experimental analysis of behavior》1988,50(3):419-440
Laboratory studies of consumer demand theory require assumptions regarding the definition of price in the absence of a medium of exchange (money). In this study we test the proposition that the fundamental dimension of price is a cost-benefit ratio expressed as the effort expended per unit of food value consumed. Using rats as subjects, we tested the generality of this "unit price" concept by varying four dimensions of price: fixed-ratio schedule, number of food pellets per fixed-ratio completion, probability of reinforcement, and response lever weight or effort. Two levels of the last three factors were combined in a 2 x 2 x 2 design giving eight groups. Each group was studied under a series of six FR schedules. Using the nominal values of all factors to determine unit price, we found that grams of food consumed plotted as a function of unit price followed a single demand curve. Similarly, total work output (responses x effort) conformed to a single function when plotted in terms of unit price. These observations provided a template for interpreting the effects of biological factors, such as brain lesions or drugs, that might alter the cost-benefit ratio. 相似文献
202.
Jeffrey S. Levin Ph.D. M.P.H. C. David Jenkins Ph.D. Robert M. Rose M. D. 《Journal of religion and health》1988,27(4):267-278
In a study of air traffic controllers, religious differences are found in the way Type A behavior is associated with several health status indicators. Associations between the Jenkins Activity Survey (JAS) and physical illness incidence, health-promotive behavior, diastolic and systolic blood pressure, subjective distress and impulse control problems, and alcohol consumption are examined by religious attendance, religious affiliation, and change in affiliation. Findings confirm that Type A does not vary significantly by religion. However, there are several significant findings between Type A and various health indicators. Type A is associated with illness incidence, overall and more strongly in several religion, subgroups. Type A and alcohol consumption are related positively in Protestants and converts, and negatively in churchgoing Catholics. Type A is related to impulse control problems in churchgoing Protestants and to subjective distress in churchgoing Catholics. Finally, in individuals with weak or no religious ties, Type A is associated with lower blood pressure. This last finding suggests that in some people (for example, the irreligious or unchurched), the coronary-prone behavior pattern may have cardiovascular effects which are salutary in at least one respect.The authors wish to thank Dr. Kyriakos S. Markides and Laura A. Ray for their assistance with this study. Address requests for reprints to Dr. Levin at the Institute of Gerontology, 300 North Ingalls, Ann Arbor, MI 48109. 相似文献
203.
204.
A general model is developed for the analysis of multivariate multilevel data structures. Special cases of the model include repeated measures designs, multiple matrix samples, multilevel latent variable models, multiple time series, and variance and covariance component models.We would like to acknowledge the helpful comments of Ruth Silver. We also wish to thank the referees for helping to clarify the paper. This work was partly carried out with research funds provided by the Economic and Social Research Council (U.K.). 相似文献
205.
Body-frame size is an important factor in determining an optimal body weight for a given height. Previous studies have indicated that many individuals incorrectly estimate their body-frame size, and, as a result, incorrectly assess their ideal weight. The present study investigated the accuracy of estimation of body-frame size as a function of sex and actual frame size. The subjects were 66 men and 52 women participating in a community adult fitness program. Data indicated that medium-framed individuals were the most accurate in their estimations of body-frame size. Also, women were twice as likely to be accurate as were men. These results are interpreted to mean that most people assume they are medium-framed and that there is a sex difference in the way body-frame size is estimated. 相似文献
206.
Effects of visual aids on acquisition of selected tennis skills 总被引:1,自引:0,他引:1
The study compared the effects of supplemental visual aids on the acquisition of selected tennis skills. The forehand and backhand drive placement tests of the Hewitt Tennis Achievement Test were used to pretest, midtest, and posttest 55 subjects who were assigned to one of three treatments: control (instructor's verbal feedback only), videotaped replay viewing (with instructor's feedback), and loop-film viewing (modeling, with instructor's feedback). Each received 1200 min. of instruction. There were no statistically significant differences among groups; however, empirical evidence suggested that the use of videotaped replay and loop-film technique has merit and might be given consideration for use in instructional settings. 相似文献
207.
We hypothesized that in the decodification of connotative aspects of visual chromatic stimuli the periphery of the body plays an important role. In particular we hypothesized that the decodification process of so called "warm" and "cold" colours is related to a real modification of the temperature of the body which is the basis of the "subjective feeling" and of the attribution of the "emotional meaning" to the stimulus. So we have measured the temperature of the body of 36 female psychology students while they were looking at a luminous screen through spectacles in which filters (coloured lenses) of different colours were placed. Analysis indicated that during the perception of so called "warm" colours a statistically significant increase in the temperature of the body appeared. We observed an enhancement of temperature on the left side of the body during the perception with red and yellow filters and a small increase in temperature on the right side of the body with orange and yellow filters. In the discussion of the results we considered also the role of the cerebral dominance in decodification process of the connotative components of stimuli. 相似文献
208.
Light-eyed individuals generally perform better at self-paced activities while dark-eyed individuals perform better at reactive activities. Using multiple regression it was found that dark-eyed students hit a target with a frisbee more times than did light-eyed students. 相似文献
209.
210.
P Brodsky 《Perceptual and motor skills》1988,66(2):383-386
The youngest subject (age 5) participating in the 1986 evaluation studies published in this Journal returned 25 mo. after finishing REHABIT training. This boy's test scores showed a significant decline in verbal ability. It was concluded that follow-up studies of REHABIT clients are necessary and that such clients should be cautioned that regression may occur. 相似文献