全文获取类型
收费全文 | 7944篇 |
免费 | 753篇 |
国内免费 | 375篇 |
出版年
2024年 | 27篇 |
2023年 | 162篇 |
2022年 | 106篇 |
2021年 | 154篇 |
2020年 | 363篇 |
2019年 | 374篇 |
2018年 | 339篇 |
2017年 | 376篇 |
2016年 | 332篇 |
2015年 | 242篇 |
2014年 | 294篇 |
2013年 | 982篇 |
2012年 | 172篇 |
2011年 | 280篇 |
2010年 | 237篇 |
2009年 | 306篇 |
2008年 | 370篇 |
2007年 | 394篇 |
2006年 | 402篇 |
2005年 | 363篇 |
2004年 | 313篇 |
2003年 | 242篇 |
2002年 | 222篇 |
2001年 | 164篇 |
2000年 | 117篇 |
1999年 | 150篇 |
1998年 | 122篇 |
1997年 | 105篇 |
1996年 | 86篇 |
1995年 | 84篇 |
1994年 | 66篇 |
1993年 | 49篇 |
1992年 | 46篇 |
1991年 | 18篇 |
1990年 | 21篇 |
1989年 | 25篇 |
1987年 | 18篇 |
1985年 | 130篇 |
1984年 | 126篇 |
1983年 | 106篇 |
1982年 | 87篇 |
1981年 | 67篇 |
1980年 | 74篇 |
1979年 | 65篇 |
1978年 | 94篇 |
1977年 | 57篇 |
1976年 | 42篇 |
1975年 | 31篇 |
1974年 | 24篇 |
1973年 | 28篇 |
排序方式: 共有9072条查询结果,搜索用时 31 毫秒
101.
A multidisciplinary group of genetic and other professionals discuss a complex case of familial conflict over access to genetic information. One twin wishes to know the results of her deceased mother's tests for BRCA1 mutations; a second twin objects to researchers making this information available. As the case discussion unfolds, the apparent facts of this case are called into question and the lines of ethical certainty become less clear. 相似文献
102.
In this paper, we examine the termination of children's mental health services. Analyses were based on the 901 families in the Fort Bragg Evaluation Project who participated at Wave 1 and Wave 2 six months later. The project compared a full continuum of care provided at a demonstration site with traditional care at two comparison sites. The results showed that in most cases families and providers were partners in decisions to terminate treatment. About half of the clients self-terminated or were terminated solely at the discretion of the provider. Providers tended to play a more dominant role in terminating restrictive services; families played a more central role in terminating outpatient care. Regardless of initial psychopathology, children in single-headed households, whose parents were dissatisfied with services, did not expect their child to cooperate with treatment and did not expect treatment to help their child, were more likely to terminate care than others. While the Demonstration site had significantly fewer terminations, the sites did not differ with regard to the reasons for termination, who participated in termination decisions, or the factors that affected the likelihood to terminate care. Of most interest, mental health outcomes among children who had terminated all care did not vary by reasons for termination or by who participated in the termination decision. 相似文献
103.
104.
自由回忆和线索回忆测验中的系列位置效应 总被引:3,自引:1,他引:2
本文以96个中国汉字为材料,使用自由回忆和线索回忆测验方法,对20名被试进行6组分测验和最后所有汉字的总测验。发现自由回忆分测验中存在明显的系列位置效应,总测验出现负近因现象;线索回忆分测验也表现出明显的系列位置效应,但最后的总测验没有出现负近因现象。上述结果验证了Bjork和Whitten(1974)提出的顺序或情景理论。 相似文献
105.
大学生解决物理问题的表征层次的实验研究 总被引:12,自引:1,他引:11
设计了两个实验,探讨优、差生物理问题表征层次的特点。结果表明,优、差生物理问题表征层次有差异。优生侧重于科学理论表征,表现为以物理原理分类,在科学理论表征层次上多为正向推理:差生则受初始表征的影响,以表面特征分类,在科学理论表征层次上多为逆向推理。 相似文献
106.
Gerard J. P. Van Breukelen 《Psychometrika》1997,62(4):525-544
This paper discusses two forms of separability of item and person parameters in the context of response time (RT) models. The first is separate sufficiency: the existence of sufficient statistics for the item (person) parameters that do not depend on the person (item) parameters. The second is ranking independence: the likelihood of the item (person) ranking with respect to RTs does not depend on the person (item) parameters. For each form a theorem stating sufficient conditions, is proved. The two forms of separability are shown to include several (special cases of) models from psychometric and biometric literature. Ranking independence imposes no restrictions on the general distribution form, but on its parametrization. An estimation procedure based upon ranks and pseudolikelihood theory is discussed, as well as the relation of ranking independence to the concept of double monotonicity.I am indebted to Wim van der Linden for bringing Thissen's (1983) paper to my notice, and to Martijn Berger, Frans Tan, and the anonymous reviewers for their constructive comments on earlier drafts of this paper. 相似文献
107.
Shrinkage estimation of linear combinations of true scores 总被引:1,自引:0,他引:1
Nicholas T. Longford 《Psychometrika》1997,62(2):237-244
This paper is concerned with combining observed scores from sections of tests. It is demonstrated that in the presence of population information a linear combination of true scores can be estimated more efficiently than by the same linear combination of the observed scores. Three criteria for optimality are discussed, but they yield the same solution which can be described and motivated as a multivariate shrinkage estimator.Input from Eric Bradlow, Charles Lewis, and Linda Zeger is acknowledged. Research for this paper was funded by the Program Research Council (ETS). Suggestions of the Editor and of anonymous referees were instrumental in several improvements of the paper. 相似文献
108.
A similarity relation is a reflexive and symmetric binary relation between objects. Similarity is relative: it depends on the set of properties of objects used in determining their similarity or dissimilarity. A multi-modal logical language for reasoning about relative similarities is presented. The modalities correspond semantically to the upper and lower approximations of a set of objects by similarity relations corresponding to all subsets of a given set of properties of objects. A complete deduction system for the language is presented. 相似文献
109.
Jan Loney Carl E. Paternite Joseph E. Schwartz Mary Ann Roberts 《Journal of abnormal child psychology》1997,25(6):499-509
The question asked in this study of 70 clinically referred 6- to 12-year-old boys with behavior problems was whether or not childhood inattention-overactivity and aggression are transmitted specifically from biological fathers to sons. Fathers' self-reported childhood inattention-overactivity on a retrospectively valid measure was exclusively associated with parents' ratings of their sons' current attention problems on the Mothers' Operational Measure for Sub-grouping (MOMS), the Revised Child Behavior Checklist (RCBCL), and an approximated DSM-IV inattention dimension. Fathers' self-reported childhood aggression was not associated with ratings of their sons' aggression on the MOMS or DADS (a parallel instrument for fathers), nor on DSM-III oppositional or conduct disorder dimensions, but it was exclusively associated with RCBCL ratings of sons' aggressive and delinquent behavior. None of the nonspecific correlations (father inattention-overactivity with son aggression or father aggression with son inattention-overactivity) was significant. 相似文献
110.
医学伦理学概念之探究 总被引:5,自引:1,他引:4
丛亚丽 《医学与哲学(人文社会医学版)》1997,18(12):637-640
医学伦理学的概念看起来很简单,一般情况下人们便习以为常地接受了作为应用规范伦理学的一个分支的科学地位,而忽视了医学对医学伦理学所起的作用。本文认为:医学伦理学的具体内容是医学科技与伦理道德两因素相互作用的产物,对其相互作用的形式和产物的具体分析和总结便可构成这门学科的理论体系。 相似文献