全文获取类型
收费全文 | 32698篇 |
免费 | 1330篇 |
国内免费 | 8篇 |
专业分类
34036篇 |
出版年
2019年 | 428篇 |
2018年 | 559篇 |
2017年 | 586篇 |
2016年 | 586篇 |
2015年 | 418篇 |
2014年 | 529篇 |
2013年 | 2373篇 |
2012年 | 972篇 |
2011年 | 1038篇 |
2010年 | 609篇 |
2009年 | 606篇 |
2008年 | 897篇 |
2007年 | 878篇 |
2006年 | 830篇 |
2005年 | 747篇 |
2004年 | 729篇 |
2003年 | 660篇 |
2002年 | 693篇 |
2001年 | 1018篇 |
2000年 | 928篇 |
1999年 | 710篇 |
1998年 | 381篇 |
1997年 | 309篇 |
1996年 | 306篇 |
1992年 | 548篇 |
1991年 | 541篇 |
1990年 | 526篇 |
1989年 | 537篇 |
1988年 | 530篇 |
1987年 | 494篇 |
1986年 | 521篇 |
1985年 | 570篇 |
1984年 | 451篇 |
1983年 | 431篇 |
1982年 | 354篇 |
1981年 | 337篇 |
1979年 | 521篇 |
1978年 | 378篇 |
1977年 | 311篇 |
1976年 | 358篇 |
1975年 | 432篇 |
1974年 | 486篇 |
1973年 | 507篇 |
1972年 | 407篇 |
1971年 | 381篇 |
1970年 | 378篇 |
1969年 | 408篇 |
1968年 | 488篇 |
1967年 | 421篇 |
1966年 | 422篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
221.
222.
Adult age differences were explored on 3 short tests of the ability to generate and manipulate mental images. Age-related decrements were found in all 3 tests and were especially marked on the Clock Test. The tests are all reliable, as shown by test-retest reliability coefficients. Correlations also revealed that the Brooks Letter Test and the East-West Test appear to tap one common underlying ability, whereas the Clock Test measured a somewhat different ability. The East-West and Clock tests, in particular, may provide rapid and easily administered assessments of age-related changes in aspects of mental imagery. 相似文献
223.
The authors used a correlated motion paradigm to investigate the effects of aging and gender on motion sensitivity. In 2 experiments with a total of 50 elderly and 50 young subjects, motion thresholds were significantly higher for elderly women. The correlated motion signal, which was embedded in random motion, may have been coherent to subjects in much the same way a form is in Witkin's Embedded Figures Test (EFT). In Experiment 2, EFT scores were obtained. A significant positive relationship between motion thresholds and EFT performance was found within each age group. Although gender-related perceptual style differences may contribute to motion perception effects, the authors argue that a common neural factor contributes to performance on both the EFT and the correlated motion task. 相似文献
224.
The construct accessibility model (CAM) holds that constructs are most likely to influence behavior when they are accessible in memory. While the theory of reasoned action sees intention as an important determinant of behavior, the CAM predicts that the intention to act upon a given health behavior is not likely to be acted upon unless the intention is in an accessible state. Therefore, people who frequently talk about or think about using condoms are likely to have condom related constructs available and use them when needed. This paper reports findings from the pilot phase of a project to identify beliefs which influence condom use in Hispanic and African-American youth living in Detroit. 15 male and 15 female Hispanics and 17 male and 17 female African-Americans aged 15-21 years of mean and median age 18.5, were interviewed face-to-face in 1989 with the goal of identifying condom beliefs which may influence their condom use. 80-82% of male participants, 53% of Hispanic females, and 100% of Black females had experienced sexual intercourse, with age at first intercourse ranging between 13.1 and 16.5 years. 88% of Black women and 7% of Hispanic women were pregnant at the interview. Regarding participants' level of preventive knowledge, all but 1 recently immigrated Hispanic female knew HIV was transmitted by needles and sexual intercourse. 87% of Hispanics and 94% of African-Americans responded that condoms protect against AIDS, but only 13% of Hispanics and 47% of African-Americans knew that nonlatex condoms do not. Some participants expressed concern that condoms reduce sensitivity and/or break during intercourse. Controlling for sexual activity, 25% of Hispanic females, 83% of Hispanic males, 71% of African-American females, and 80% of African-American males had ever used a condom; no Hispanic and 14% of Blacks reported using them consistently in the 12 month period preceding the interview. With 100% of African-American males and 97% of Black females reporting thinking about using condoms compared to 80% of Hispanics, the study findings suggest that condom intentions are more accessible in African-Americans than among Hispanics. 相似文献
225.
226.
Robert T. Carter Janet E. Helms 《Journal of multicultural counseling and development》1992,20(4):181-201
Helms (1984) presented a model to explain the influence of Black and White racial identity development on counseling interactions. The purpose of this study was to examine her hypothesis that specific combinations of racial identity attitudes contribute to qualitatively different counseling process and outcome or relationship types. 相似文献
227.
Susan E. Bernick 《希帕蒂亚:女权主义哲学杂志》1992,7(1):1-15
Catharine MacKinnon's investigation of the role of sexuality in the subordination of women is a logical culmination of radical feminist thought. If this is correct, the position of her work relative to radical feminism is analogous to the place Parmenides's work occupied in ancient Greek philosophy. Critics of MacKinnon's work have missed their target completely and must engage her work in a different way if feminist theory is to progress past its current stalemated malaise. 相似文献
228.
229.
Randolph W. Parks Daniel S. Levine Debra L. Long David J. Crockett Irene E. Dalton Herbert Weingartner Paul Fedio Kerry L. Coburn Gil Siler Jane R. Matthews Robert E. Becker 《Neuropsychology review》1992,3(2):213-233
Neural networks can be used as a tool in the explanation of neuropsychological data. Using the Hebbian Learning Rule and other such principles as competition and modifiable interlevel feedback, researchers have successfully modeled a widely used neuropsychological test, the Wisconsin Card Sorting Test. One of these models is reviewed here and extended to a qualitative analysis of how verbal fluency might be modeled, which demonstrates the importance of accounting for the attentional components of both tests. Difficulties remain in programming sequential cognitive processes within a parallel distributed processing (PDP) framework and integrating exceedingly complex neuropsychological tests such as Proverbs. PDP neural network methodology offers neuropsychologists co-validation procedures within narrowly defined areas of reliability and validity. 相似文献
230.
Miller TE 《Kennedy Institute of Ethics journal》1992,2(1):43-59
Recently, debate about the distribution of scarce organs for transplantation has focused on whether patients should have the right to place themselves on waiting lists at several transplant centers, thereby gaining an advantage over other potential recipients. This article explores the social and ethical issues raised by multiple listing, contrasting policies adopted at the national level with those implemented in New York State. It concludes by examining the implications of the debate for broader questions about entitlement and access to health care. 相似文献