全文获取类型
收费全文 | 63366篇 |
免费 | 2570篇 |
国内免费 | 43篇 |
专业分类
65979篇 |
出版年
2020年 | 760篇 |
2019年 | 955篇 |
2018年 | 1348篇 |
2017年 | 1354篇 |
2016年 | 1430篇 |
2015年 | 970篇 |
2014年 | 1208篇 |
2013年 | 5819篇 |
2012年 | 2122篇 |
2011年 | 2318篇 |
2010年 | 1367篇 |
2009年 | 1393篇 |
2008年 | 2078篇 |
2007年 | 2054篇 |
2006年 | 1836篇 |
2005年 | 1695篇 |
2004年 | 1641篇 |
2003年 | 1564篇 |
2002年 | 1587篇 |
2001年 | 1953篇 |
2000年 | 1837篇 |
1999年 | 1447篇 |
1998年 | 826篇 |
1997年 | 749篇 |
1996年 | 671篇 |
1995年 | 658篇 |
1994年 | 625篇 |
1993年 | 633篇 |
1992年 | 1129篇 |
1991年 | 1077篇 |
1990年 | 1054篇 |
1989年 | 942篇 |
1988年 | 887篇 |
1987年 | 890篇 |
1986年 | 912篇 |
1985年 | 997篇 |
1984年 | 802篇 |
1983年 | 698篇 |
1982年 | 574篇 |
1981年 | 543篇 |
1980年 | 543篇 |
1979年 | 743篇 |
1978年 | 581篇 |
1976年 | 536篇 |
1975年 | 674篇 |
1974年 | 710篇 |
1973年 | 670篇 |
1972年 | 589篇 |
1968年 | 561篇 |
1967年 | 564篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
221.
There is usually a long period of time between infection with the AIDS virus and manifestation of symptoms. Asymptomatic patients often would benefit from elective surgery for diseases such as arthritis which are unrelated to their infection. The surgeons' decisions to accept the risks to themselves, their spouses, and their operating teams in order to relieve pain and suffering appear to be based upon two covenants; one concerns their role within the doctor-patient relationship, and the other concerns their relationship to what they see as the ultimate meaning in life. 相似文献
222.
In Phase 1 of this study, we asked 23 parents between the ages of 30 and 52 years and 26 children between the ages of 10 and 19 years to list effects of television and video games on children. A questionnaire was developed using the most frequently given responses (e.g., television influences children's aggressive behavior, verbal abilities, or time with friends). In Phase 2, this questionnaire was administered to different groups of parents and children and a control group of adults without offspring (N = 204) who were asked to rate the influence of each item on the questionnaire. Multivariate analyses of variance indicated that there were similarities and differences among the groups. For example, parents and other adults held similar beliefs about the influence of television, but parents held more positive beliefs about the influence of video games than the other adults. Children held more positive beliefs about the influence of television than parents, but parents and children held similar beliefs about the influence of video games. 相似文献
223.
Dinsmoor JA Dougan JD Pfister J Thiels E 《Journal of the experimental analysis of behavior》1992,58(2):265-276
In the first experiment, 4 pigeons were each presented with a recurring sequence of four key colors followed by the delivery of grain (block clock). Once the rate of pecking had stabilized, three of the colors were replaced, during different series of sessions, by a darkening of the key. The rate of pecking was reduced within those segments of the interval between deliveries of food during which the key was dark; when the key was dark during the final portion of the interval, rates were reduced throughout the entire interval. In the second experiment, 3 new pigeons were exposed to a different sequence of colors, and the final stimulus was replaced in successive conditions by a novel color, a darkened key, and a restoration of the original color. The data indicated that darkening the key had a more severe, more extensive, and more persistent effect than did a mere change in color. These results suggest that it may be fruitful to conceptualize the autoshaping procedure as a special version of the block clock in which pecking is suppressed throughout the greater part of the interval by darkening the key. In the final condition, the same stimulus appeared in each of the last three portions of the interval. The rate of pecking was lower during the last two portions than when distinctive colors were presented, with the peak rate now appearing in the fifth of seven equal temporal components. 相似文献
224.
Bruhn AR 《Journal of personality assessment》1992,58(2):326-346
In Part 1 of this paper, topics germane to the projective assessment of autobiographical memory were discussed. In Part 2, the cognitive-perceptual method will be used to interpret several early memories and a slightly abridged Early Memories Procedure (EMP). 相似文献
225.
226.
This study examined the effect of demographic variables and intellectual factors on the Short-term Memory Test. Subjects were 20 patients neurologically diagnosed as brain-damaged. There was only one significant correlation between Verbal IQ and the Short-term Memory Test. Demographic variables of age, education, and sex did not correlate significantly with scores of the Short-term Memory Test. 相似文献
227.
The scores of 15 adolescents who had a primary diagnosis of Posttraumatic Stress Disorder, 21 of Conduct Disorder, and 23 control subjects on the Beck and Reynolds depression scales were correlated .58 over-all, .73 for the Posttraumatic group, .48 for the Conduct Disordered group, but .37 for controls. The Reynolds scale did not identify depression in these adolescents as effectively as did the Beck scale. 相似文献
228.
A Compton 《The Psychoanalytic quarterly》1992,61(3):400-425
This is the third part of a review and commentary on the psychoanalytic literature on phobias. This section takes up agoraphobia and other phobias of adults, and suggests further avenues for interpenetration of psychoanalytic and psychiatric approaches. 相似文献
229.
Analyses of responses from a clinical sample of 120 patients (primarily schizophrenics) and from 158 college students to the Cognitive Slippage Scale, a scale designed by Miers and Raulin to identify speech deficits and confused thinking in schizophrenic and schizotypal personality disorders showed high internal reliability; Cronbach's coefficients alpha were .89 and .86 in the clinical and college student samples, respectively. The mean scale scores significantly differentiated the two samples. Also, change scores over 4 wk. showed adequate stability for both samples. Item analysis indicated Items 11, 20, 21, and 28 may not reliably discriminate between schizophrenic and college student samples. Over-all, these preliminary results are consistent with the reliability and validity of the scale. 相似文献
230.
In this paper we study the acquisition of German noun plurals in relation to the question of how children represent regular and irregular inflection. Pinker and Prince (1992) have demonstrated several dissociations between regular and irregular inflection in the English past tense system. However, in English, the default status of -ed is confounded with its high frequency; therefore inflectional systems other than English past tense formation must be examined. The noun plural system in German is particularly interesting, because most nouns have irregular plurals in German and the regular (default) plural is less frequent than several of the irregular plurals. Thus it is unclear how a language learner determines whether German even has a regular plural, and if so what form it takes. Based on longitudinal data from impaired and unimpaired monolingual German-speaking children, we find a striking, statistically significant correlation: plural affixes that are used in overregularizations, namely -n or -s, are left out within compounds. This correlation shows that even impaired children are sensitive to the distinction between regular and irregular morphology. We propose a linguistic analysis of the correlation in terms of Kiparsky's (1982, 1985) level-ordering model plus an additional ordering condition on affixes: default (regular) affixes cannot serve as input to compounding processes. 相似文献