全文获取类型
收费全文 | 3704篇 |
免费 | 550篇 |
国内免费 | 833篇 |
专业分类
5087篇 |
出版年
2024年 | 5篇 |
2023年 | 81篇 |
2022年 | 125篇 |
2021年 | 134篇 |
2020年 | 230篇 |
2019年 | 215篇 |
2018年 | 210篇 |
2017年 | 229篇 |
2016年 | 259篇 |
2015年 | 150篇 |
2014年 | 211篇 |
2013年 | 658篇 |
2012年 | 170篇 |
2011年 | 213篇 |
2010年 | 123篇 |
2009年 | 179篇 |
2008年 | 183篇 |
2007年 | 191篇 |
2006年 | 169篇 |
2005年 | 156篇 |
2004年 | 124篇 |
2003年 | 112篇 |
2002年 | 71篇 |
2001年 | 70篇 |
2000年 | 48篇 |
1999年 | 45篇 |
1998年 | 32篇 |
1997年 | 34篇 |
1996年 | 24篇 |
1995年 | 33篇 |
1994年 | 25篇 |
1993年 | 31篇 |
1992年 | 23篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 40篇 |
1984年 | 45篇 |
1983年 | 37篇 |
1982年 | 48篇 |
1981年 | 43篇 |
1980年 | 53篇 |
1979年 | 48篇 |
1978年 | 44篇 |
1977年 | 41篇 |
1976年 | 32篇 |
1975年 | 12篇 |
1974年 | 29篇 |
1973年 | 20篇 |
排序方式: 共有5087条查询结果,搜索用时 15 毫秒
41.
Rapp R 《Journal of genetic counseling》1993,2(3):183-196
This article reports on an anthropological investigation of the social impact and cultural meaning of amniocentesis conducted in New York City, illustrating how class differences, as well as sociocultural diversity, deeply affect pregnant women's acceptance, rejection, and interpretation of prenatal testing. The article also suggests the importance of recognizing how counselors' cultural backgrounds and styles affect patient-counselor communications. 相似文献
42.
Predictive testing for Huntington disease is presently offered in a select few medical genetics centers in the United States. This is in part due to the labor intensive counseling and psychological testing suggested by the research protocols. We discuss some specific suggestions for establishing programs for Huntington disease predictive testing within pre-existing medical genetics clinics to encourage more centers to offer presymptomatic testing. This will allow more at risk individuals the opportunity to consider predictive testing and cut down the expenses of traveling to the few predictive testing centers that currently exist. The counseling principals will remain similar to those discussed here, even following the identification of the Huntington disease mutation. 相似文献
43.
Gary M. Pace Brian A. Iwata Glynnis Edwards Cowdery Peter J. Andree Therese McIntyre 《Journal of applied behavior analysis》1993,26(2):205-212
Three individuals with developmental disabilities were exposed to a series of assessment conditions to identify the source of reinforcement for their self-injurious behavior. In each case, self-injury occurred most often in instructional (demand) situations containing a brief time-out from the task contingent on self-injury, indicating that the behavior was an escape response (i.e., maintained by negative reinforcement). Treatment was implemented in a multiple baseline across subjects design and consisted of extinction (prevention of escape) plus instructional fading (initial elimination of instructions followed by their gradual reintroduction). Results showed that the combined treatment produced immediate and large reductions in self-injury that were maintained as the frequency of instructions was increased across sessions to match the original baseline rate of presentation. Results of a component analysis conducted with 1 subject suggested that stimulus fading accelerated the behavior-reducing effects of extinction. 相似文献
44.
Unit price as a useful metric in analyzing effects of reinforcer magnitude. 总被引:7,自引:6,他引:1 下载免费PDF全文
R J DeGrandpre W K Bickel J R Hughes M P Layng G Badger 《Journal of the experimental analysis of behavior》1993,60(3):641-666
In this paper, we applied the behavioral-economic concept of unit price to the study of reinforcer magnitude in an attempt to provide a consistent account of the effects of reinforcer magnitude on behavior. Recent research in the experimental analysis of behavior and in behavioral pharmacology suggests that reinforcer magnitude interacts with the schedule of reinforcement to determine response rate and total consumption. The utility of the unit-price concept thus stems from its ability to quantify this interaction as a cost-benefit ratio (i.e., unit price = characteristics of the schedule of reinforcement divided by magnitude of reinforcement). Research employing the unit-price concept has shown that as unit price increases, a positively decelerating function exists for consumption (i.e., a function with an increasingly negative slope, when plotted on log coordinates) and a bitonic function exists for response rate. Based on these findings, the present analysis applied the unit-price concept to those studies of reinforcer magnitude and drug self-administration that examined the effects of reinforcer magnitude on response rate using simple schedules of reinforcement (e.g., fixed-ratio schedule). This resulted in three findings: (a) Reinforcer-magnitude manipulations and schedule manipulations interact in a manner that can be quantified in terms of unit price as benefit and cost factors, respectively; (b) different reinforcer-magnitude manipulations are functionally interchangeable as benefit factors in the unit-price ratio; and (c) these conclusions appear warranted despite the differences in reinforcers (food or drug), species (dogs, monkeys, or rats), and schedules (interval or ratio), and despite the fact that these studies were not designed for a unit-price analysis. In methodological terms, these results provide further evidence that employing the unit-price concept is a parsimonious method for examining the effects of reinforcer magnitude. In theoretical terms, these results suggest that a single process may underlie the effect of combined reinforcer-magnitude and schedule manipulations. 相似文献
45.
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
46.
The cloning of BRCA1, a susceptibility gene for inherited breast cancer, has made genetic screening possible for individuals and families whose medical histories are suggestive of an inherited predisposition to breast cancer. To date, few systematic attempts have been made to determine the level of knowledge about breast cancer genetics among women who are likely to seek BRCA1 screening when it becomes widely available. The present study attempted to assess the general knowledge about BRCA1 mutations in two groups: (1) first-degree relatives (FDRs) of breast cancer patients; and (2) women with a previous diagnosis of breast cancer. A self-administered, thirty-item questionnaire was developed through a pilot study. Ten of the items were objective, factual questions about breast cancer genetics. Responses to these questions were used to generate an overall knowledge score for each respondent. The study population was moderately knowledgeable about breast cancer genetics, with an average score of 5.35 out of 10. Counselors should not underestimate the importance of evaluating each counselee's existing knowledge about breast cancer, which can affect the provision and reception of genetic information. In particular, specific areas of knowledge that may be confusing or misunderstood were identified and these topics are discussed in detail. 相似文献
47.
实验用实字、虚字、与被试自身相关字三类汉字作刺激材料,将直接测量(再认任务)和间接测量(喜好判断任务)进行匹配,考察了被试对不同类别汉字在两种测量方式中的反应。结果发现:实字和虚字间在各种不同的实验处理中均未表现出明显的差异;中性汉字和自我关联汉字都在直接测量的两种注意水平间产生了显著差异,而在间接测量时未产生显著差异;“拥有效应”的作用不是单向的,当自我关联汉字处于注意焦点以外的位置时,直接测量出现了反转的结果。 相似文献
48.
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
49.
小学儿童对习俗时间的周期性特点的认知 总被引:2,自引:0,他引:2
本研究探讨了小学儿童对习俗时间周期性特点的认知发展.实验任务是让被试判断两个给定日期之间的时间距离是正向接近还是反向接近。结果表明:儿童对习俗时间的周期性特点的认知成绩随年龄增长而不断提高;随着两个日期之间距离的增大,反应时不断增加,正确率不断降低,在两个日期相互接近的方向发生改变的边界处,反应时最长,正确率最低,表现出显著的“距离效应”和“边界效应”;儿童可以利用数字系统进行判断,他们的认知加工策略包括计数、数字运算和凭借习俗时间的空间表象进行模拟加工等等。 相似文献
50.
人性观对心理学理论与研究的影响 总被引:5,自引:0,他引:5
心理学的基本理论,尤其是人格理论,通常都蕴含着对人性的假设。人性观的差异常常导致其理论建构的差异。而且人性观影响心理学研究的方式、方法,影响对心理成因的认识、对心理疾病的理解、及对异常矫正策略的选择。 相似文献