首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   17494篇
  免费   365篇
  国内免费   7篇
  17866篇
  2021年   135篇
  2020年   240篇
  2019年   248篇
  2018年   356篇
  2017年   359篇
  2016年   370篇
  2015年   282篇
  2014年   312篇
  2013年   1325篇
  2012年   572篇
  2011年   650篇
  2010年   375篇
  2009年   351篇
  2008年   475篇
  2007年   455篇
  2006年   396篇
  2005年   334篇
  2004年   340篇
  2003年   319篇
  2002年   323篇
  2001年   700篇
  2000年   699篇
  1999年   463篇
  1998年   182篇
  1997年   175篇
  1996年   139篇
  1995年   135篇
  1993年   139篇
  1992年   360篇
  1991年   322篇
  1990年   345篇
  1989年   334篇
  1988年   318篇
  1987年   288篇
  1986年   310篇
  1985年   298篇
  1984年   235篇
  1983年   200篇
  1979年   191篇
  1978年   163篇
  1975年   188篇
  1974年   245篇
  1973年   199篇
  1972年   204篇
  1971年   169篇
  1970年   151篇
  1969年   198篇
  1968年   202篇
  1967年   161篇
  1966年   182篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
771.
This prospective study evaluates emotional functioning and illness representations in 68 unaffected women (34 carriers/34 noncarriers) 1 year after predictive testing for BRCA1/2 mutations when offered within a multidisciplinary approach. Carriers had higher subjective risk perception of breast cancer than noncarriers. Carriers who did not have prophylactic oophorectomy had the highest risk perception of ovarian cancer. No differences were found between carriers and noncarriers regarding perceived seriousness and perceived control of breast and ovarian cancer. Mean levels of distress were within normal ranges. Only few women showed an overall pattern of clinically elevated distress. Cancer-specific distress and state-anxiety significantly decreased in noncarriers from pre- to posttest while general distress remained about the same. There were no significant changes in distress in the group of carriers except for ovarian cancer distress which significantly decreased from pre- to posttest. Our study did not reveal adverse effects of predictive testing when offered in the context of a multidisciplinary approach.  相似文献   
772.
To continue research assessing the validity of the Balloon Analog Risk Task (BART) as a measure of risk taking, the BART was administered to a nonforensic sample of individuals with varying levels of psychopathic characteristics. Construct validity of the BART was evaluated by measuring risk-taking behavior in relation to self-reported psychopathy, anxiety, psychophysiological data, and demographic variables. Supporting the construct validity of the BART, while controlling for variance accounted for by interrelated variables in the context of hierarchical regression analyses, higher self-reported psychopathy was significantly predictive of increased risk taking on the BART. Findings also revealed interesting gender differences in self-reported psychopathy and a trend for men to engage in riskier behavior. Limitations and research directions are presented.  相似文献   
773.
Participants’ eye movements to four objects displayed on a computer screen were monitored as the participants clicked on the object named in a spoken instruction. The display contained pictures of the referent (e.g., a snake), a competitor that shared features with the visual representation associated with the referent’s concept (e.g., a rope), and two distractor objects (e.g., a couch and an umbrella). As the first sounds of the referent’s name were heard, the participants were more likely to fixate the visual competitor than to fixate either of the distractor objects. Moreover, this effect was not modulated by the visual similarity between the referent and competitor pictures, independently estimated in a visual similarity rating task. Because the name of the visual competitor did not overlap with the phonetic input, eye movements reflected word-object matching at the level of lexically activated perceptual features and not merely at the level of preactivated sound forms.  相似文献   
774.
Von Economo neurons (VENs) are a recently evolved cell type which may be involved in the fast intuitive assessment of complex situations. As such, they could be part of the circuitry supporting human social networks. We propose that the VENs relay an output of fronto-insular and anterior cingulate cortex to the parts of frontal and temporal cortex associated with theory-of-mind, where fast intuitions are melded with slower, deliberative judgments. The VENs emerge mainly after birth and increase in number until age 4 yrs. We propose that in autism spectrum disorders the VENs fail to develop normally, and that this failure might be partially responsible for the associated social disabilities that result from faulty intuition.  相似文献   
775.
The issue of how to best minimize scientific misconduct remains a controversial topic among bioethicists, professors, policymakers, and attorneys. This paper suggests that harsher criminal sanctions against misconduct, better protections for whistleblowers, and the creation of due process standards for misconduct investigations are urgently needed. Although the causes of misconduct and estimates of problem remain varied, the literature suggests that scientific misconduct-fraud, fabrication, and plagiarism of scientific research-continues to damage public health and trust in science. Providing stricter criminal statutes against misconduct is necessary to motivate whistleblowers and deter wrongdoers, and the provision of basic due process protections is necessary for ensuring a fair and balanced misconduct investigation.  相似文献   
776.
This article reports on the feasibility of using interactive voice response (IVR) technology to obtain daily reports of attitudes toward alcohol and tobacco use among children 9–13 years of age. Two studies were conducted. The first was an investigation of the use of IVR technology to obtain daily data from a sample of primary school children over a period of 8 weeks. The second was an extension of the research to a large sample of primary and secondary school children in urban and rural areas who provided daily data over a 4-week period. Retention and compliance rates comparable to those obtained with adults were evident in both studies, supporting the feasibility of this technology with children. The results are discussed in relation to the benefits of this methodology for health research, particularly for studies of sensitive topics conducted with children and adolescents.  相似文献   
777.
A prospective examination of body image and smoking cessation in women   总被引:2,自引:2,他引:0  
This study prospectively examined body image in a community sample of women smokers (N = 141, 89% European–American, M age = 39.5, M BMI = 25.5) participating in a 12-week randomized smoking cessation trial. Participants completed measures assessing subjective and perceptual aspects of body image. Regression analyses showed that subjective body image was predictive of smoking rate at the end of treatment. A MANCOVA revealed that perceptual body image (body size estimation) significantly predicted smoking cessation. Quitting smoking actually worsened body image, although these results were no longer significant after controlling for weight gain. Results support the theory that a negative body image may hamper cessation attempts. In addition, weight gain during smoking cessation may adversely impact body image and lead to an increased risk for relapse.  相似文献   
778.
779.
Most research on the rapid mental processes of on-line language processing has been limited to the study of idealized, fluent utterances. Yet speakers are often disfluent, for example, saying "thee, uh, candle" instead of "the candle." By monitoring listeners' eye movements to objects in a display, we demonstrated that the fluency of an article ("thee uh" vs. "the") affects how listeners interpret the following noun. With a fluent article, listeners were biased toward an object that had been mentioned previously, but with a disfluent article, they were biased toward an object that had not been mentioned. These biases were apparent as early as lexical information became available, showing that disfluency affects the basic processes of decoding linguistic input.  相似文献   
780.
Using micro-video cameras attached to the heads of 2 dogs, we examined their optical behavior while catching Frisbees. Our findings reveal that dogs use the same viewer-based navigational heuristics previously found with baseball players (i.e., maintaining the target along a linear optical trajectory, LOT, with optical speed constancy). On trials in which the Frisbee dramatically changed direction, the dog maintained an LOT with speed constancy until it apparently could no longer do so and then simply established a new LOT and optical speed until interception. This work demonstrates the use of simple control mechanisms that utilize invariant geometric properties to accomplish interceptive tasks. It confirms a common interception strategy that extends both across species and to complex target trajectories.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号