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   3398篇
  免费   108篇
  国内免费   3篇
  2023年   21篇
  2022年   43篇
  2021年   48篇
  2020年   78篇
  2019年   93篇
  2018年   137篇
  2017年   134篇
  2016年   170篇
  2015年   82篇
  2014年   92篇
  2013年   426篇
  2012年   125篇
  2011年   131篇
  2010年   101篇
  2009年   129篇
  2008年   121篇
  2007年   137篇
  2006年   111篇
  2005年   104篇
  2004年   85篇
  2003年   81篇
  2002年   72篇
  2001年   54篇
  2000年   48篇
  1999年   41篇
  1998年   41篇
  1997年   45篇
  1996年   57篇
  1995年   63篇
  1994年   40篇
  1993年   37篇
  1992年   29篇
  1991年   21篇
  1990年   28篇
  1989年   17篇
  1987年   20篇
  1986年   17篇
  1985年   17篇
  1984年   23篇
  1983年   28篇
  1982年   45篇
  1981年   28篇
  1980年   33篇
  1979年   25篇
  1978年   22篇
  1977年   24篇
  1976年   18篇
  1975年   22篇
  1974年   25篇
  1973年   45篇
排序方式: 共有3509条查询结果,搜索用时 15 毫秒
31.
We investigated the role of implicit and explicit associations between harm and COVID-19 vaccines using a large sample (N = 4668) of online volunteers. The participants completed a brief implicit association test and explicit measures to evaluate the extent to which they associated COVID-19 vaccines with concepts of harmfulness or helpfulness. We examined the relationship between these harmfulness/helpfulness COVID-19 vaccine associations and vaccination status, intentions, beliefs, and behavior. We found that stronger implicit and explicit associations that COVID-19 vaccines are helpful relate to vaccination status and beliefs about the COVID-19 vaccine. That is, stronger pro-helpful COVID-19 vaccine associations, both implicitly and explicitly, related to greater intentions to be vaccinated, more positive beliefs about the vaccine, and greater vaccine uptake.  相似文献   
32.
COVID-19 has altered adolescents' opportunities for developing and strengthening interpersonal skills and proficiencies. Using data from adolescents in Italy, the United States, and the United Kingdom, we examined the relation between internalizing symptoms assessed pre-pandemic or when pandemic-related restrictions were lifted (Time 1) and associated internalizing symptoms during a subsequent restrictive pandemic period (Time 2). Across all 3 countries, we found significant and consistent effect sizes in the relation between Time 1 and Time 2 internalizing symptoms. We further examined the direct and moderating impact of self-efficacy and contextual supports for adolescents' internalizing symptoms. Higher self-efficacy was associated with lower levels of internalizing symptoms at Time 2 in all 3 countries. Additionally, the relation between Time 1 and 2 internalizing symptoms was buffered by regulatory self-efficacy and peer support in Italy, but in the U.S., higher levels of general self-efficacy instead had an exacerbating effect on the relation between Times 1 and 2 internalizing symptoms. Results are discussed in the context of utilizing cross-national datasets to examine similarities in adolescent well-being over time and in the face of varying government responses to the pandemic.  相似文献   
33.
COVID-19 vaccination is widely regarded as an individual decision, resting upon individual characteristics and demographic factors. In this research, we provide evidence that psychological group membership, and more precisely, social cohesion—a multidimensional concept that encompasses one's sense of connectedness to, and interrelations within, a group—can help us understand COVID-19 vaccination intentions (Study 1) and uptake (Study 2). Study 1 is a repeated-measures study with a representative sample of 3026 Australians. We found evidence that social cohesion can be conceptualised as a multidimensional structure; moreover, social cohesion at Wave 1 (early in the COVID-19) predicted greater vaccination intention and lower perceived risk of vaccination at Wave 2 (4 months later). In Study 2 (a cross-sectional study, N = 499), the multidimensional structure of social cohesion was associated with greater uptake of vaccine doses (in addition to willingness to receive further doses and perceived risk of the vaccine). These relations were found after controlling for a series of demographic (i.e., sex, age, income), health-related factors (i.e., subjective health; perceived risk; having been diagnosed with COVID-19), and individual differences (political orientation, social dominance orientation, individualism). These results demonstrate the need to go beyond individual factors when it comes to behaviours that protect groups, and particularly when examining COVID-19 vaccination—one of the most important ways of slowing the spread of the virus.  相似文献   
34.
A study was designed to compare several variables of Manpower Development Training Act (MDTA) clients who dropped out of the program with those of clients who completed the program. A random sample of application cards was drawn for individuals enrolled in MDTA adult classes in Milwaukee, Wisconsin. Trainees who completed the program were more likely to be married, older, characterized by a more stable employment history prior to entering the program, and slightly more educated than were program dropouts. Clients who completed the program versus those who did not were not significantly different on the following variables: (1) sex; (2) counseling versus no counseling; (3) race; and (4) client reported physical disability.  相似文献   
35.
The Pulfrich pendulum was evaluated as a potential screening device for the detection of anomalies of binocular vision. For this purpose, a booth was set up at the Kentucky State Fair (1964) and the general public invited to observe the pendulum and record their responses with the equipment provided. The obtained results indicate that a dichotomy can be achieved between those who have binocular vision and those who do not. However, gradations of binocular vision from poor to good cannot be achieved with the pendulum as presently understood. Contrary to explanatory theory the characteristic shape of the seen pendulum path was asymmetrical following the rule that the path was displaced away from the observer on the side of the filtered eye.  相似文献   
36.
Hardware is described that permits bidirectional transfer of data between the Commodore 64 and an IBM-compatible PC. Commercial terminal programs can be used to transmit data. The hardware, which can be constructed for less than $15, opens up several opportunities for making good use of the cost-effective C64 computer.  相似文献   
37.
38.
In this paper a method is outlined for measuring the diversity of the results of applied R&D with the use of IPC (International Patent Classification). The method has been tested in the contexts of the academic physical, engineering, and chemical institutes. The trend of applied research at a given institute increases both at the level of classes and subclasses, and at the IPC level. Inventions developed within specializations at each institute have a greater efficiency than other forms of inventive activity. The objective was to seek the optimal extent of diversification of applied R&D, which would simultaneously ensure the preservation of the scientific specialization of an institute, the high level of scientific research associated with developing innovations, and the high overall efficiency of each institute.  相似文献   
39.
Finland has followed the Scandinavian model of the welfare state in which the level of state activism is high, the economic pressures on the scientific activities are strong, and the left-wing parties and the Center Party have formulated the main ideas. In the 1970s welfare ideology was adopted in science policy by emphasizing the promotion of socially relevant scientific activities and the expansion of the university system as a means of effecting equal opportunity. Currently, the trend is toward a mixed welfare economy. Programs have been prepared in spite of the radical cut in government expenditure, and without a consideration of the long-term consequences.  相似文献   
40.
This article describes an important new area of research on services for children and adolescents with mental disorders at the National Institute of Mental Health, the parameters of mental health services research for youth, and the opportunities that are available for grant-funded investigations in this area.  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