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   2395764篇
  免费   196740篇
  国内免费   4267篇
耳鼻咽喉   34641篇
儿科学   73596篇
妇产科学   63578篇
基础医学   337776篇
口腔科学   68167篇
临床医学   217574篇
内科学   473169篇
皮肤病学   48494篇
神经病学   203010篇
特种医学   96663篇
外国民族医学   889篇
外科学   362827篇
综合类   56597篇
现状与发展   1篇
一般理论   1017篇
预防医学   192330篇
眼科学   55847篇
药学   178765篇
  4篇
中国医学   4373篇
肿瘤学   127453篇
  2018年   24595篇
  2016年   20897篇
  2015年   23619篇
  2014年   34015篇
  2013年   51585篇
  2012年   69745篇
  2011年   73307篇
  2010年   43092篇
  2009年   41393篇
  2008年   69697篇
  2007年   74110篇
  2006年   75025篇
  2005年   72971篇
  2004年   70254篇
  2003年   67825篇
  2002年   67143篇
  2001年   113010篇
  2000年   117062篇
  1999年   98814篇
  1998年   28103篇
  1997年   25730篇
  1996年   25646篇
  1995年   24792篇
  1994年   23350篇
  1993年   21752篇
  1992年   79829篇
  1991年   76829篇
  1990年   73933篇
  1989年   71193篇
  1988年   66203篇
  1987年   65151篇
  1986年   61660篇
  1985年   58785篇
  1984年   44518篇
  1983年   37929篇
  1982年   23086篇
  1981年   20489篇
  1980年   19176篇
  1979年   41561篇
  1978年   29170篇
  1977年   24507篇
  1976年   23021篇
  1975年   24144篇
  1974年   29835篇
  1973年   28224篇
  1972年   26397篇
  1971年   24324篇
  1970年   22908篇
  1969年   21212篇
  1968年   19266篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Consecutive patients (n = 215) who were referred to optometric (55%) or multidisciplinary (45%) low-vision services and above 50 years of age were recruited from four hospitals in the Netherlands. They completed two vision-related quality of life questionnaires, the Vision Quality of Life Core Measure (VCM1) and the Low Vision Quality of Life Questionnaire (LVQOL), before their first visit with low-vision services and 1 year later. At follow-up, patients referred to multidisciplinary low-vision services had lower scores on the mobility subscale of the LVQOL than patients referred to optometric low-vision services [5.3 points; 95% confidence interval (CI): 0.2-10.5]. Paired sample t-tests for the two groups of patients taken together show improvement for the VCM1 (3.1 points; 95% CI: 0.6-5.6) and deterioration for the basic aspects of vision (3.5 points; 95% CI: 1.1-5.9) and the mobility (6.6 points; 95% CI: 3.7-9.5) subscales of the LVQOL. In conclusion, people referred to optometric services showed less deterioration in mobility than those referred to multidisciplinary services. No differences were observed for any of the other subscales of the LVQOL and the VCM1. Future research in this field should include randomized controlled designs comparing low-vision services with no treatment or placebo.  相似文献   
83.
This prospective clinic-based study evaluated the pretreatment periodontal status of the orthodontic patients seen at the University College Hospital, Ibadan, Nigeria, and assessed the relationship between dental aesthetic index (DAI) scores and periodontal status according to community periodontal index of treatment needs (CPITN) scores. One hundred forty five patients-70 (48.3%) males and 75 (51.7%) females from 6 to 45 years (mean 15.8 +/- 7.5)-were seen. World Health Organization (WHO) guidelines were followed in the examination and reporting of the periodontal status, and DAI scores were assessed based on WHO guidelines. The chi-square test was used to determine the association between the DAI and the CPITN scores. Most patients were in the 6-15 (55.9%) or 16-25 (35.9%) age groups. Based on the WHO preferred cumulative calculations of treatment need (TN), 35.2% of the patients had TN 0, 64.9% had TN 1, 24.9% had TN 2, and only 0.7% had TN 3. The relationship between DAI scores and periodontal treatment needs was not statistically significant (P >.05). Although many patients were yet to attain the WHO goal of no more than 1 sextant affected by bleeding or calculus at the age of 15, over one third had satisfactory periodontal health.  相似文献   
84.
Summary: The mosaic (Atp7a mo-ms ) is an X-linked, lethal mutation in mice. In mosaic mutant males, many clinical features characteristic of defective copper metabolism have been observed and they die at the age of 15 days, exhibiting strongsimilarities to the brindled and macular mutants. About 4% of the mutant males live to sexual maturity and some of them are fertile. In this paper, alterationsin the structure of the kidney from adult mutants are described. Owing to an inherited defect of efflux, copper is accumulated in the kidney of the mutants up to a toxic level and this leads to severe damage of the renal cortex. Pathological changes in the kidney mostly affected the structure of the renal corpuscle and renaltubules.  相似文献   
85.
86.
OBJECTIVE: To determine whether under-reporting of rheumatic fever occurs at hospital, municipal, provincial and national levels of the South African health system. BACKGROUND: Information on the incidence of rheumatic fever (RF) and the prevalence of rheumatic heart disease (RHD) is required for the prevention of valvular heart disease in developing countries. In South Africa, RF was made a notifiable condition in 1989. It has recently been suggested that the reporting of RF cases may be incomplete, possibly because of underreporting by health care professionals and deficient administration of the disease notification system in South Africa. METHOD AND RESULTS: We assessed whether underreporting of RF cases occurs by comparing the numbers of RF cases reported per year at hospital, municipal, provincial and national levels from 1990 to 2004. There was a fall in the number of RF cases reported per year at national and provincial level over the 15 years of observation. A detailed analysis of the number of RF cases reported at hospital, municipal and provincial level for a 5-year period showed that more cases were diagnosed in one hospital (serving a smaller population) than were captured at municipal and provincial level (serving a larger population), suggesting underreporting by health care professionals. There were discrepancies in the number of cases reported at municipal, provincial and national level, suggesting poor administration of the notification system. CONCLUSION: There appears to be underreporting of RF cases by health care professionals, and poor administration of the RF notification system. Health care professionals need to be educated about the statutory requirement to notify all RF cases in South Africa. An effective national disease notification system is required.  相似文献   
87.
88.
89.
90.
This article describes the proceedings of the 2006 Annual Meeting of the Fetal Alcohol Spectrum Disorders Study Group (FASDSG), which was held in Baltimore, Maryland on June 24, 2006. The meeting was held in conjunction with the annual meeting of the Research Society on Alcoholism and was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism. The 2005-2006 FASDSG officers, Daniel J. Bonthius (President), Heather Carmichael Olson (Vice-President), and Jennifer Thomas (Secretary-Treasurer), organized the meeting. Nationally prominent speakers delivered plenary lectures on topics of newborn screening, ethics, and neuroscience. Selected members of the FASDSG provided brief scientific data (FASt) reports, describing new research findings. Representatives from national agencies involved in fetal alcohol syndrome (FAS) research, treatment, and prevention provided updates regarding priorities, funding, and agency activities. Presentations were also made by the 2006 Student Merit Award recipient and by the 2006 Rosett Award recipient. The meeting served as a forum for clinicians, neuroscientists, psychologists, social scientists, and other professionals to discuss recent advances in FAS research and to identify the most important gaps in the understanding of alcohol-induced teratology.  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