全文获取类型
收费全文 | 22013篇 |
免费 | 865篇 |
国内免费 | 11篇 |
出版年
2019年 | 258篇 |
2018年 | 373篇 |
2017年 | 398篇 |
2016年 | 423篇 |
2015年 | 319篇 |
2014年 | 351篇 |
2013年 | 1757篇 |
2012年 | 632篇 |
2011年 | 654篇 |
2010年 | 395篇 |
2009年 | 370篇 |
2008年 | 496篇 |
2007年 | 553篇 |
2006年 | 474篇 |
2005年 | 451篇 |
2004年 | 425篇 |
2003年 | 416篇 |
2002年 | 442篇 |
2001年 | 746篇 |
2000年 | 715篇 |
1999年 | 542篇 |
1998年 | 221篇 |
1996年 | 225篇 |
1995年 | 198篇 |
1992年 | 452篇 |
1991年 | 445篇 |
1990年 | 429篇 |
1989年 | 401篇 |
1988年 | 422篇 |
1987年 | 377篇 |
1986年 | 390篇 |
1985年 | 389篇 |
1984年 | 309篇 |
1983年 | 278篇 |
1982年 | 206篇 |
1981年 | 208篇 |
1979年 | 351篇 |
1978年 | 255篇 |
1977年 | 215篇 |
1976年 | 199篇 |
1975年 | 282篇 |
1974年 | 355篇 |
1973年 | 367篇 |
1972年 | 290篇 |
1971年 | 284篇 |
1970年 | 281篇 |
1969年 | 251篇 |
1968年 | 349篇 |
1967年 | 308篇 |
1966年 | 284篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
Douglas B. Eamon 《Behavior research methods》1992,24(2):174-179
Modern spreadsheets are powerful and useful tools that can often replace special-purpose programs for generating data and for student analysis of simple statistical problems. The inherent flexibility of spreadsheets makes them especially convenient and extensible. Several templates for generating and analyzing data fort tests and analysis of variance are discussed. Users can specify then, \(\bar X\) , andSD of two or more groups and then execute macros that generate appropriate data. Overwriting the generated data with “real” values turns the spreadsheet into a data analysis program. Spreadsheets hold promise as valuable instructional supplements for simple designs, but they are less suitable for more complex designs, where special-purpose programs may be more appropriate. 相似文献
182.
Oblique contours sloping at 30° with respect to the horizontal were presented alone, in combination to form chevrons, or with a vertical line to form arrowhead or Y patterns; they were projected onto a screen in the frontal parallel plane and viewed from positions that gave viewing angles of 90° (normal to the screen’s surface), 53°, or 34°. The perceived orientation of the contours, as assessed by a movable arm that the subjects set to be parallel to the obliques, changed monotonically as a function of viewing angle. The change was as great for single obliques as for combinations of obliques within the chevron, arrowhead, and Y patterns. The results of Experiment 1 were extended in Experiment 2, in which obliques at 30° and 50° with respect to the horizontal were presented singly or in combination as chevron patterns. It is argued that the results of both experiments indicate that single two-space oblique lines are immediately interpreted as lying in three-space and that the changes in perceived orientation are a consequence of this perceptual inference. 相似文献
183.
184.
The caudal portion of the hypoglossal nucleus (nXIIts) contains the motor neurons that control the syrinx in songbirds. In canaries, song occurs seasonally, is principally produced by males, and appears to be produced predominantly by muscles on the left side of the syrinx. The present study measures the effect of seasonal change and manipulation of testosterone levels on synapse number and morphology in nXIIts in adult female canaries. We find that synapse density is lower in testosterone-treated birds than in control birds and lower in fall than in spring. The number of vesicles per presynaptic profile increases in the spring as a result of a general increase in this measure in all synapses. The number of vesicles per presynaptic profile also increases with testosterone treatment, primarily due to an increase in the proportion of synapses associated with unusually high vesicle counts. Together, these changes suggest that large reserves of neurotransmitter may be necessary to sustain singing. Several ultrastructural differences between hemispheres are found. Postsynaptic thickenings are longer, and postsynaptic processes are larger on the left side than on the right side. In the spring, there are more vesicles per synapse on the left than on the right, but this lateralization is reversed in the fall. Thus, lateralization of song production is associated with lateral asymmetries in synapse morphology. These hemispheric differences are relatively small, like those seen at the light microscope level, encouraging further consideration of peripheral as well as CNS sources of functional lateralization. The seasonal and testosterone-induced changes in synapse number and morphology may be components of the periodic reorganization of canary vocalization. 相似文献
185.
M H Erdelyi J Finks M B Feigin-Pfau 《Journal of experimental psychology. General》1989,118(3):245-254
We explored Roediger and Payne's proposal that response bias does not affect recall performance and that it is therefore not necessary to control for response productivity in recall studies. Two initial experiments, contrary to expectation, corroborated Roediger and Payne's findings: Forced recall did not produce more correct recalls than free recall, even though forced recall produced substantially more false alarms than did free recall. However, in succeeding experiments involving pictorial and verbal stimuli, reliable response-bias effects on recall were demonstrated. The stimuli yielding response-bias effects were those associated with higher probabilities of being guessed by chance. In addition, some of the data suggest that processing-bias effects (differential retrieval effort) may be unintentionally induced by instructions and may significantly affect recall memory. Consequently, it is necessary to assess or to control response-bias effects and, possibly, processing-bias effects in recall experiments in which level of recall is of interest. 相似文献
186.
L B Johns 《Perceptual and motor skills》1989,68(2):359-364
This investigation explored the interaction of progressive-part versus whole methods of practice with hemispheric preference for processing information and the impact of each upon high school students' speed and accuracy in beginning typewriting. Zenhausern's Differential Hemispheric Activation Test was scored in such a way that it was possible to plot the scores along a continuum. Analysis of variance gave significant F ratios on 3 of the 4 testing days. The continuous scores were divided into five categories: middle, left moderates, right moderates, extreme rights, and extreme lefts. The moderate-left group speed was consistently the fastest group, and the extreme rights were consistently the slowest group. This difference was significant for all four testing days with the moderate-left mean speed varying between 4 to 6 words per minute faster each testing day. The extreme rights were consistently the most accurate, even though not statistically significantly so. There was no significant difference between method of practice and typewriting speed or between method of practice and typewriting accuracy; however, on all four testing days the mean gross speed of the whole practice learning group was 0.73 to 0.99 words per minute faster than the progressive-part group. A two-way analysis of variance indicated no interaction between method or practice and hemispheric preference. 相似文献
187.
188.
J B Murray 《Psychological reports》1989,64(2):627-644
Alcoholism among women often has been treated using a model based on research with alcoholic men. Women react differently to alcohol than men both physiologically and psychologically and their drinking patterns are different from men's. Treatment facilities for alcoholism have not been as available for women as for men and treatment must be individualized for the differences between men and women problem drinkers and for the differences among alcoholic women. 相似文献
189.
C B Steinberger 《Psychoanalytic review》1989,76(1):1-18
The "crossroads families" are caught between old value systems and American mainstream goals. Traditional family and sex-related roles and orientations conflict with those of the new social system. In turn, neither of the teenager's orientations--toward home or toward peer activity--is validated. In the clinical case presented, Anna, at adolescence, wants to relinquish many of her household chores and enter her social world more fully. She needs unconflictual support for such a move. If this does not take place, her autonomous movement represents an unconscious betrayal of her depleted and controlling mother as well as an abandonment of the parental coalition. This leaves her feeling resentful, guilty, and ultimately unlovable. Attitudes marked by helplessness and confusion are thus significant to the depressed affect that brings this teenager into family therapy. Teenagers of non-Hispanic background who enter family therapy reveal gross overlap with teenagers of the Hispanic "crossroads" family model. Here, the family gives mixed messages for homebound and intimate closeness as well as accomplishment in the societal mainstream. A primary difference between ethnic groups involves the freer expressions of anger and pain between husband and wife in the non-Hispanic families. This is not similar to the backgrounds of the more individuated Hispanic teenagers. While more open expressions of anger within the family do indicate higher levels of autonomy, the hostility that is expressed by the parents presents serious complications when this includes "triangulating" the child into the family tension. Here, as cited, the mother often uses her daughter as a confidant and ally at times of severe parental discord. This places additional strain on the child's conflict with separation. Importantly, the daughter experiences renewed rejection and betrayal when the mother "submits" to her spouse. These are significant family processes that heighten mixed messages around autonomy. Milagros, a depressed (more individuated) adolescent, is consistently entangled into her parent's abrasive relationship. Her interpersonal family struggles have become intrapsychic and, ultimately, transferential. 相似文献
190.
Trace mineral analysis of human hair was utilized to determine whether violent and nonviolent criminals could be differentiated on the basis of concentrations of levels of major and trace minerals. 40 violent and 40 nonviolent inmates from a prison population were selected for study. 27 mineral levels were analyzed and a discriminant function analysis correctly classified 86% of the violent and 78% of the nonviolent inmates. The results lent support to the hypothesis that significantly different levels of trace minerals could be found between the two groups. 相似文献