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   113522篇
  免费   30474篇
  国内免费   1109篇
耳鼻咽喉   2598篇
儿科学   3035篇
妇产科学   2470篇
基础医学   4463篇
口腔科学   5234篇
临床医学   27863篇
内科学   27786篇
皮肤病学   3485篇
神经病学   13763篇
特种医学   4184篇
外国民族医学   1篇
外科学   20741篇
综合类   420篇
现状与发展   40篇
一般理论   23篇
预防医学   14858篇
眼科学   2489篇
药学   1951篇
中国医学   23篇
肿瘤学   9678篇
  2024年   757篇
  2023年   5156篇
  2022年   1448篇
  2021年   3472篇
  2020年   5668篇
  2019年   2571篇
  2018年   7532篇
  2017年   7725篇
  2016年   8314篇
  2015年   8450篇
  2014年   11072篇
  2013年   12832篇
  2012年   5023篇
  2011年   4737篇
  2010年   7400篇
  2009年   9568篇
  2008年   4316篇
  2007年   3226篇
  2006年   4224篇
  2005年   2730篇
  2004年   2084篇
  2003年   1690篇
  2002年   1454篇
  2001年   2040篇
  2000年   1369篇
  1999年   1869篇
  1998年   2172篇
  1997年   1970篇
  1996年   2015篇
  1995年   1797篇
  1994年   1228篇
  1993年   1042篇
  1992年   942篇
  1991年   804篇
  1990年   647篇
  1989年   686篇
  1988年   657篇
  1987年   497篇
  1986年   476篇
  1985年   425篇
  1984年   348篇
  1983年   381篇
  1982年   288篇
  1981年   240篇
  1980年   169篇
  1979年   159篇
  1978年   180篇
  1977年   168篇
  1976年   137篇
  1974年   129篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
31.
32.
33.
34.
Milos Jesenak  MD  PhD    Peter Banovcin  MD  PhD    Zuzana Rennerova  MD  PhD    Lubica Jakusova  MD  PhD    Zuzana Havlicekova  MD  PhD    Vladimir Pohanka  MD  PhD  MPH  FCCP    Maria Pia Villa  MD  PhD    Roberto Ronchetti  MD  PhD 《International journal of dermatology》2009,48(9):941-946
Background  The atopy patch test (APT) is no longer an experimental method; it is increasingly being used as a standard diagnostic tool for the characterization of patients with aeroallergen- and food-triggered disorders. Some technical aspects of this test still remain to be answered. We aimed to study the reproducibility of this test over time in the general child population.
Methods  In a general population of 118 children, we investigated the reproducibility of duplicate APTs with four food allergens in their native form, which were repeated at set intervals from the first test: 7 days (group 1), 14 days (group 2), and 21 days (group 3).
Results  We observed very poor reproducibility on both sides of the back in all three studied subgroups. The reproducibility rates and Cohen's κ values did not improve when we did not consider the side of the back. There were no differences in the prevalence of atopy between the subjects with reproducible and nonreproducible APT results. All three groups studied showed no difference in the prevalence rates of atopy. There was no relationship between APT and skin prick test positivity for the same allergen. Questionnaire-derived data about previous food-related reactions did not help in the evaluation of the doubtful nonreproducible APT results with food allergens.
Conclusions  Our results show that the reproducibility of food APTs is poor and unsatisfactory over time, and there is an urgent need for the development of optimal, stable, and good-quality APT testing substances.  相似文献   
35.
36.
Iron deficiency may exacerbate symptoms in the Restless Legs Syndrome (RLS). We investigated the effect of intravenous iron sucrose or placebo on symptoms in patients with RLS and mild to moderate iron deficit. Sixty patients with primary RLS (seven males, age 46 (9) years, S‐ferritin ≤45 μg/L) recruited from a cohort of 231 patients were randomly assigned in a 12‐months double‐blind, multi‐centre study of iron sucrose 1000 mg (n = 29) or saline (n = 31). The primary efficacy variable was the RLS severity scale (IRLS) score at week 11. Median IRLS score decreased from 24 to 7 (week 11) after iron sucrose and from 26 to 17 after placebo (P = 0.123, N.S. for between treatment comparison). The corresponding scores at week 7 were 12 and 20 in the two groups (P = 0.017). Drop out rate because of lack of efficacy at 12 months was 19/31 after placebo and 5/29 patients after iron sucrose (Kaplan–Meier estimate, log rank test P = 0.0006) suggesting an iron induced superior long term RLS symptom control. Iron sucrose was well tolerated. This study showed a lack of superiority of iron sucrose at 11 weeks but found evidence that iron sucrose reduced RLS symptoms both in the acute phase (7 weeks) and during long‐term follow up in patients with variable degree of iron deficiency. Further studies on target patient groups, dosing and dosing intervals are warranted before iron sucrose could be considered for treatment of iron deficient patients with RLS. © 2009 Movement Disorder Society  相似文献   
37.
38.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  相似文献   
39.
40.
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