全文获取类型
收费全文 | 33326篇 |
免费 | 1292篇 |
国内免费 | 19篇 |
出版年
2020年 | 332篇 |
2019年 | 456篇 |
2018年 | 620篇 |
2017年 | 701篇 |
2016年 | 629篇 |
2015年 | 462篇 |
2014年 | 539篇 |
2013年 | 2624篇 |
2012年 | 932篇 |
2011年 | 1045篇 |
2010年 | 678篇 |
2009年 | 684篇 |
2008年 | 939篇 |
2007年 | 880篇 |
2006年 | 821篇 |
2005年 | 707篇 |
2004年 | 641篇 |
2003年 | 695篇 |
2002年 | 624篇 |
2001年 | 1216篇 |
2000年 | 1188篇 |
1999年 | 870篇 |
1998年 | 391篇 |
1996年 | 309篇 |
1995年 | 315篇 |
1994年 | 321篇 |
1992年 | 734篇 |
1991年 | 705篇 |
1990年 | 674篇 |
1989年 | 621篇 |
1988年 | 596篇 |
1987年 | 594篇 |
1986年 | 553篇 |
1985年 | 621篇 |
1984年 | 483篇 |
1983年 | 385篇 |
1979年 | 475篇 |
1978年 | 346篇 |
1977年 | 335篇 |
1976年 | 312篇 |
1975年 | 422篇 |
1974年 | 422篇 |
1973年 | 484篇 |
1972年 | 388篇 |
1971年 | 324篇 |
1970年 | 311篇 |
1969年 | 327篇 |
1968年 | 380篇 |
1967年 | 340篇 |
1966年 | 387篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
291.
Mary I. Armstrong M.S.W. M.B.A. Mary E. Evans Ph.D. 《Journal of child and family studies》1992,1(1):61-74
Systems of care for children with serious emotional disturbance and their families have generally lacked intensive community-based programs. We describe three types of newly established community-based programs in New York State and present a general evaluation plan for determining which programs work for various children and their families. The three community-based programs are Intensive Case Management, Family-Based Treatment, and Family-Centered Intensive Case Management. Process and outcome evaluations are being conducted for each of these programs. These evaluations make use of common intake and termination instruments, based on a minimum data set, standardized assessment instruments, and a common logic model, thus facilitating the comparison of findings across evaluations. 相似文献
292.
A new method for determining the minimum number of observations per subject needed to achieve a specific generalizability coefficient is presented. This method, which consists of a branch-and-bound algorithm, allows for the employment of constraints specified by the investigator. 相似文献
293.
Age-dependent facilitation of taste-footshock conditioning by prior exposure to the training context
Among adult rats, gustatory stimuli are easily associated with illness, but not with external unconditioned stimuli such as footshock. Recent evidence indicates, however, that this cue-to-consequence specificity may vary ontongenetically. The present studies examined the acquisition of an aversion to a taste paired with footshock in 5- and 15-day-old rats. Consistent with previous reports, 5-day-old rats avoided the taste that preceded footshock, while 15-day-old subjects did not express an aversion to the taste paired with footshock. Exposure to the training context for either 1 or 5 h prior to conditioning disrupted taste-footshock conditioning in the 5-day-old subjects. For the 15-day-old subjects, 1 h of pre-conditioning exposure to the training context had no effect on conditioning, whereas a longer duration of preexposure promoted conditioning to the taste cue. The results suggest ontogenetic differences in stimulus selection. 相似文献
294.
J Brener S Mitchell 《Journal of experimental psychology. Animal behavior processes》1989,15(2):166-175
The principle of least effort predicts that behavior will tend to maximum efficiency. To test this prediction, changes in the energy expended (VO2) and work performed per reinforcement were monitored continuously as rats learned to press a beam with a criterion force for liquid food rewards. All 12 subjects exhibited significant decreases in energy expended per reinforcement over the 16 days of observation. Of these, 10 subjects also decreased the work performed per reinforcement. Analyses of motor performance were undertaken to determine how motor programs for changing efficiency were generated. The 10 animals showing decreased work reinforcement also exhibited significant decreases in the variability of temporal and kinetic response features and in mean response magnitude (time integral of force or work per response) as a function of practice. Adjustments in work output were primarily accomplished by modifying temporal response features (response duration and, initially, interresponse time). The kinetic features (response recruitment and peak force) remained relatively constant for these animals. The remaining 2 subjects differed in that response recruitment increased after Day 9, resulting in progressively larger amounts of work being performed to earn each reinforcement, and the interval between successive reinforcements decreased. 相似文献
295.
The Y chromosome, social signals, and offense in mice 总被引:1,自引:0,他引:1
Offense is one type of aggression in mice (Mus musculus/Mus domesticus). Offense was measured in a panel of testers design for two congenic strains of mice. The two congenic strains were DBA1Bg and DBA1. C57BL10-YBg. These differ in the Y chromosome. Offense was measured for the following dyadic pairs: Group 1 (DBA1 tested against a DBA1 opponent); Group 2 (DBA1 tested against a DBA1.C57BL10-Y opponent); Group 3 (DBA1.C57BL10-Y tested against a DBA1.C57BL10-Y opponent); and Group 4 (DBA1.C57BL10-Y tested against a DBA1 opponent). Group 1 was more aggressive than Group 3, whereas Group 2 was no more aggressive than Group 4. Thus, when the experimental and opponent pairs have the same Y chromosome, the congenics differ in offense, whereas when the experimental and opponent pairs have different Y chromosomes, the congenics do not differ in offense. These findings are consistent with the hypothesis that these Y chromosomes affect the display of and response to social or other stimuli for offense of mice. These stimuli may be individual recognition chemosignals in urine. 相似文献
296.
Pigeons searched arrays of small forms displayed on computer monitors. On each trial, a single target form appeared together with two or more identical distractor forms. A set of six different forms was used in each of three experiments. All possible combinations of these forms, paired as target and distractor, appeared in each experimental session. Both the accuracy and speed of search increased with the number of distractors displayed. When both targets and distractors were new, accuracy was above chance only for the large (24 item) display, where transfer was highly significant. The experiments do not support the attribution to pigeons of a general "oddity concept." Rather, the results suggest that odd-item performance depends in part on a perceptual isolation of the target and in part on familiarity with target-distractor combinations. 相似文献
297.
Varieties of size-specific visual selection 总被引:1,自引:0,他引:1
Compared time to evaluate stimuli of varying sizes. When Ss expect an upcoming stimulus to be a certain size, response time increases with the disparity between expected and actual size. There are, however, 2 size adjustment processes, and they reflect 2 types of visual selection. In the first, a shape-specific image representation is used to separate a visual object from a superimposed distractor. These representations require the type of slow size scaling demonstrated in imagery experiments. The second size scaling process is faster and not shape-specific. At any given time the visual system is set to process information at a particular scale, and that scale can be adjusted to match an object's size. Because both selection mechanisms depend on size, they probably occur at a relatively low, spatially organized processing level. These findings lead to a new explanation for results that had been taken as evidence for attentional selection at the level of object representations. 相似文献
298.
HARRY S. BROUDY 《Counseling and values》1989,33(2):83-91
This article is an examination of the political (public consensus) and nonpolitical authority as a basis for values education in a democratic society. The author advocates that nonpolitical authority can be a basis for defending the teaching of values in public schools. 相似文献
299.
300.
This study examined the relations among physical fitness, body image, and locus of control. The Hall-Physical Fitness Test Profile, the Winstead and Cash Body Self-relations Questionnaire (BSRQ) and the Nowicki-Strickland Locus of Control Scale were administered to 243 freshmen. Women were significantly more positive about their physical appearance than men. Men were more positive about their physical fitness than women. Men were more physically fit than women. Men and women scoring in the internal direction viewed the physical fitness domain of their body image positively. Unlike men, internally oriented women had more positive perceptions of the health aspect of their body image. Physically fit men and women had positive attitudes toward the physical fitness component of their body image. Physically fit men differed from physically fit women in that men were more internal and held more positive attitudes toward the physical health dimension of their body images. 相似文献