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   18319篇
  免费   1551篇
  国内免费   60篇
耳鼻咽喉   166篇
儿科学   659篇
妇产科学   446篇
基础医学   2804篇
口腔科学   441篇
临床医学   1735篇
内科学   4008篇
皮肤病学   530篇
神经病学   1588篇
特种医学   599篇
外国民族医学   1篇
外科学   2265篇
综合类   214篇
一般理论   20篇
预防医学   1590篇
眼科学   452篇
药学   1050篇
中国医学   4篇
肿瘤学   1358篇
  2021年   215篇
  2019年   204篇
  2018年   254篇
  2017年   176篇
  2016年   212篇
  2015年   230篇
  2014年   326篇
  2013年   485篇
  2012年   717篇
  2011年   741篇
  2010年   393篇
  2009年   402篇
  2008年   732篇
  2007年   753篇
  2006年   721篇
  2005年   753篇
  2004年   665篇
  2003年   660篇
  2002年   666篇
  2001年   640篇
  2000年   719篇
  1999年   575篇
  1998年   243篇
  1997年   204篇
  1996年   179篇
  1995年   192篇
  1994年   173篇
  1993年   178篇
  1992年   497篇
  1991年   502篇
  1990年   439篇
  1989年   452篇
  1988年   423篇
  1987年   432篇
  1986年   411篇
  1985年   393篇
  1984年   356篇
  1983年   243篇
  1982年   161篇
  1981年   160篇
  1980年   195篇
  1979年   265篇
  1978年   222篇
  1977年   172篇
  1976年   183篇
  1975年   173篇
  1974年   215篇
  1973年   202篇
  1972年   169篇
  1971年   165篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
1.
2.
3.
Inbred mouse strains are the most widely used mammalian model organism in biomedical research owing to ease of genetic manipulation and short lifespan; however, each inbred strain possesses a unique repertoire of deleterious homozygous alleles that can make a specific strain more susceptible to a particular disease. In the current study, we report dystrophic cardiac calcinosis (DCC) in C.B‐17 SCID male mice at 10 weeks of age with no significant change in cardiac function. Acquisition of DCC was characterized by myocardial injury, fibrosis, calcification, and necrosis of the tissue. At 10 weeks of age, 38% of the C.B‐17 SCID mice from two different commercial colonies exhibited significant calcinosis on the ventricular epicardium, predominantly on the right ventricle. The frequency of calcinosis was more than 50% for mice obtained from Taconic's Cambridge City colony and 25% for mice obtained from Taconic's German Town colony. Interestingly, the DCC phenotype did not affect cardiac function at 10 weeks of age. No differences in echocardiography or electrocardiography were observed between the calcinotic and non‐calcinotic mice from either colony. Our findings suggest that C.B‐17 SCID mice exhibit DCC as early as 10 weeks of age with no significant impact on cardiac function. This strain of mice should be cautiously considered for the study of cardiac physiology.  相似文献   
4.
5.
6.
7.
BACKGROUND: Until there is a definitive demonstration that early diagnosis and treatment of prostate cancer reduces disease-related mortality, it is imperative to promote informed screening decisions by providing balanced information about the potential benefits and risks of prostate cancer screening. Within a community/academic collaboration, we conducted a randomized trial of a printed booklet and a videotape that were designed for African American (AA) men. The purpose of the trial was to determine the effect of the interventions on knowledge, decisional conflict, satisfaction with the screening decision, and self-reported screening. METHODS: Participants were 238 AA men, ages 40 to 70 years, who were members of the Prince Hall Masons in Washington, DC. Men were randomly assigned to the (a) video-based information study arm, (b) print-based information study arm, or (c) wait list control study arm. Intervention materials were mailed to men at home. Assessments were conducted at baseline, 1 month, and 12 months postintervention. Multivariate analyses, including ANCOVA and logistic regression, were used to analyze group differences. RESULTS: The booklet and video resulted in a significant improvement in knowledge and a reduction in decisional conflict about prostate cancer screening, relative to the wait list control. Satisfaction with the screening decision was not affected by the interventions. Self-reported screening rates increased between the baseline and the 1-year assessment, although screening was not differentially associated with either of the interventions. In exploratory analyses, prostate-specific antigen testing at 1 year was more likely among previously screened men and was associated with having low baseline decisional conflict. CONCLUSIONS: This study represents one of the first randomized intervention trials specifically designed to address AA men's informed decision making about prostate cancer screening. We have developed and evaluated culturally sensitive, balanced, and disseminable materials that improved knowledge and reduced decisional conflict about prostate cancer screening among AA men. Due to the high incidence and mortality rates among AA men, there is a need for targeted educational materials, particularly materials that are balanced in terms of the benefits and risks of screening.  相似文献   
8.
A proportionate mortality ratio (PMR) analysis of 1071 deaths in pulp and paper mill workers in New Hampshire during 1975-85 showed an increase in cancers of the digestive tract and lymphopoietic tissues. A similar analysis of deaths for 452 timber cutters and loggers failed to show excess PMRs for cancers of these sites. Despite methodological constraints, these results suggest that one or more of the exposures experienced by pulp and paper mill workers may pose a significant carcinogenic risk. More definitive epidemiological studies are required to determine particular high risk processes or specific aetiological agents.  相似文献   
9.
10.
Perceptual asymmetry on a series of four specially constructed dichotic word tests was found to change as a function of the emotional quality of the words in the tests (P = 0.05). This was most pronounced in the case of positively valued words which produced an increase in asymmetry consistent with facilitated left-hemisphere function (P less than 0.004). Changes in asymmetry with emotion differed as a function of personality characteristics of the subjects, with repressors and high anxious subjects showing an increase with emotion while true low anxious subjects showed a decrease (P less than 0.02). Personality groups also differed in asymmetry on an emotionally neutral test (P less than 0.04) and in changes in asymmetry over time independent of emotion (P less than 0.001). These data suggest that emotion mediated activation of the left hemisphere may facilitate information processing within that hemisphere. Moreover, they indicate that dichotic listening tests may provide a non-invasive and inexpensive method for assessing emotion mediated changes in brain state that are clinically relevant.  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