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   22961篇
  免费   164篇
  2023年   36篇
  2022年   57篇
  2021年   78篇
  2020年   110篇
  2019年   90篇
  2018年   3588篇
  2017年   2934篇
  2016年   2346篇
  2015年   266篇
  2014年   171篇
  2013年   439篇
  2012年   768篇
  2011年   2564篇
  2010年   2621篇
  2009年   1521篇
  2008年   1863篇
  2007年   2285篇
  2006年   145篇
  2005年   271篇
  2004年   219篇
  2003年   176篇
  2002年   102篇
  2001年   56篇
  2000年   86篇
  1999年   34篇
  1998年   36篇
  1997年   31篇
  1996年   14篇
  1995年   8篇
  1994年   9篇
  1993年   11篇
  1992年   9篇
  1991年   17篇
  1990年   16篇
  1989年   10篇
  1988年   9篇
  1987年   8篇
  1986年   7篇
  1985年   13篇
  1983年   5篇
  1981年   6篇
  1980年   5篇
  1979年   5篇
  1976年   5篇
  1975年   5篇
  1972年   6篇
  1971年   6篇
  1968年   9篇
  1966年   7篇
  1965年   9篇
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
261.
Pratt, Adam, and Fischer (2007) investigated the effect of surrounding targets on the time it took to move to an individual target and found that the movement time to a central target was above the Fitts’s law line related to the first and last targets. They explained their results in terms of a “visuomotor hypothesis.” Here, an alternative explanation is given in terms of a previously validated model of the “available target width” that is determined by the size of the target and the width of the finger pad that is being used to hit the target.  相似文献   
262.
Ecological valence theory (EVT; Palmer & Schloss, Proceedings of the National Academy of Sciences 107:8877–8882, 2010) proposes that color preferences are due to affective responses to color-associated objects: That is, people generally like colors to the degree that they like the objects associated with those colors. Palmer and Schloss found that the average valence of objects associated with a color, when weighted by how well the objects matched the color (weighted affective valence estimates: WAVE) explained 80% of the variation in preference across colors. Here, we replicated and extended Palmer and Schloss’s investigation to establish whether color–object associations can account for sex differences in color preference and whether the relationship between associated objects and color preference is equally strong for males and females. We found some degree of sex specificity to the WAVEs, but the relationship between WAVE and color preference was significantly stronger for males than for females (74% shared variance for males, 45% for females). Furthermore, analyses identified a significant inverse relationship between the number of objects associated with a color and preference for the color. Participants generally liked colors associated with few objects and disliked colors associated with many objects. For the sample overall and for females alone, this association was not significantly weaker than the association of the WAVE and preference. The success of the WAVE at capturing color preference was partly due to the relationship between the number of associated objects and color preference. The findings identify constraints of EVT in its current form, but they also provide general support for the link between color preference and color–object associations.  相似文献   
263.
Adolescence is characterized by major developmental changes that may render the individual vulnerable to stress and the development of psychopathologies in a sex-specific manner. Earlier we reported lower anxiety-like behavior and higher risk-taking and novelty seeking in rats previously exposed to peri-pubertal stress. Here we studied whether peri-pubertal stress affected the acquisition and extinction of fear memories and/or the associated functional engagement of various brain regions, as assessed with 2-deoxyglucose. We showed that while peri-pubertal stress reduced freezing during the acquisition of fear memories (training) in both sexes, it had a sex-specific effect on extinction of these memories. Moreover hippocampus, basal amygdala and cingulate and motor cortices showed higher metabolic rates during extinction in rats exposed to peri-pubertal stress. Interestingly, activation of the infralimbic cortex was negatively correlated with freezing during extinction only in control males, while only males stressed during puberty showed a significant correlation between behavior during extinction and metabolic activation of hippocampus, amygdala and paraventricular nucleus. No correlations between brain activation and behavior during extinction were observed in females (control or stress). These results indicate that exposure to peri-pubertal stress affects behavior and brain metabolism when the individual is exposed to an additional stressful challenge. Some of these effects are sex-specific.  相似文献   
264.
The objective of the study is to assess views of age related changes in sexual behavior among married Thai adults age 53–57. Results are viewed in the context of life course theory. In-depth interviews were conducted with 44 Thai adults in Bangkok and the four regions of Thailand. Topics covered include changing sexual behavior with age, adjustment to this change, gender differences in behavior, attitudes toward commercial sex and other non-marital sexual partners, and condom use. Most respondents were aware of this change and saw a decrease in sexual activity and desire more often among women compared to men. At the same time, many respondents viewed sexuality as important to a marriage. Some respondents accepted the decrease in sexual activity and focused more on work, family and temple activities. Thai Buddhism was seen as an important resource for people who were dealing with changes due to aging. Other persons turned to other partners including both commercial and non-commercial partners. The influence of the HIV epidemic that began in the 1990s was seen in concerns about disease transmission with extramarital partners and consequent attitudes toward condom use. The acceptability of extramarital partners in the family and community ranged from acceptance to strong disapproval of extramarital relationships.  相似文献   
265.
The recent trend in the feminization of the HIV epidemic poses great risk to women, especially to the wives of men who have sex with men (MSM). The objective of the present study was to explore wives’ responses to their husbands’ sexual orientation as well as the factors that influence their sexual health in India. For this research, 15 wives who were aware of their husbands’ sexual orientation and their husbands were interviewed separately using semi-structured in-depth interviews and focus groups. The study explored the social and cultural structures that create gender inequality, which put women married to MSM at sexual health risk. These factors need to be addressed carefully through existing MSM targeted interventions, without breaching the confidentiality of either partner.  相似文献   
266.
Between 1998 and 2006, twenty-seven states amended their constitutions to prohibit same sex marriage. The 2008 elections again saw three states with ballot measures aimed at banning gay marriage. This study examines the determinants of support for those measures in California and Florida, and includes a similar measure placed on the primary election ballot in California in 2000. Support is measured as the county-wide vote in favor of each gay marriage ban. A number of hypotheses are explored that examine the urban/rural nature of each county, as well as the political and demographic characteristics of county residents. It is suggested that states may be best viewed as relatively independent groupings of diverse subcultures, rather than as homogenous populations with a single political culture. The findings reported here indicate that a host of demographic, political and religious differences within each state influence residents’ votes on gay marriage bans.  相似文献   
267.
This study broaches in a novel way the analysis of cognitive impairment characteristic of the early stages of Alzheimer's Disease (AD). Specifically, we attempt to determine the acoustic speech parameters that are sensitive to the onset of the disease, and their association with the language deficit characteristic of AD. Speech analysis was carried out on 21 elderly patients with AD using Praat software, which analyzes the acoustic components of speech. The data obtained were subjected to stepwise regression, using the overall scores obtained in the test as the criterion variable, and the scores on the frequency, amplitude and periodicity variables as predictors of performance. We found that the percentage of voiceless segments explains a significant portion of the variance in the overall scores obtained in the neuropsychological test. This component seems to be related mainly to the patient's ability in phonological fluency. This finding could permit the creation of a diagnostic test for AD through analysis of the acoustic speech parameters at very low cost in terms of both time and resources.  相似文献   
268.
The Center for Epidemiologic Studies-Depression Scale (CES-D) is the most frequently used scale for measuring depressive symptomatology in caregiving research. The aim of this study is to test its construct structure and measurement equivalence between caregivers from two Spanish-speaking countries. Face-to-face interviews were carried out with 595 female dementia caregivers from Madrid, Spain, and from Coahuila, Mexico. The structure of the CES-D was analyzed using exploratory and confirmatory factor analysis (EFA and CFA, respectively). Measurement invariance across samples was analyzed comparing a baseline model with a more restrictive model. Significant differences between means were found for 7 items. The results of the EFA clearly supported a four-factor solution. The CFA for the whole sample with the four factors revealed high and statistically significant loading coefficients for all items (except item number 4). When equality constraints were imposed to test for the invariance between countries, the change in chi-square was significant, indicating that complete invariance could not be assumed. Significant between-countries differences were found for three of the four latent factor mean scores. Although the results provide general support for the original four-factor structure, caution should be exercised on reporting comparisons of depression scores between Spanish-speaking countries.  相似文献   
269.
In 2008 a young man committed suicide while his webcam was running. 1,500 people apparently watched as the young man lay dying: when people finally made an effort to call the police, it was too late. This closely resembles the case of Kitty Genovese in 1964, where 39 neighbours supposedly watched an attacker assault and did not call until it was too late. This paper examines the role of internet mediation in cases where people may or may not have been good Samaritans and what their responsibilities were. The method is an intuitive one: intuitions on the various potentially morally relevant differences when it comes to responsibility between offline and online situations are examined. The number of onlookers, their physical nearness and their anonymity have no moral relevance when it comes to holding them responsible. Their perceived reality of the situation and ability to act do have an effect on whether we can hold people responsible, but this doesn’t seem to be unique to internet mediation. However the way in which those factors are intrinsically connected to internet mediation does seem to have a diminishing effect on responsibility in online situations.  相似文献   
270.
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