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   1860838篇
  免费   152327篇
  国内免费   6002篇
耳鼻咽喉   26487篇
儿科学   61297篇
妇产科学   49027篇
基础医学   247871篇
口腔科学   50731篇
临床医学   178722篇
内科学   380755篇
皮肤病学   46017篇
神经病学   147606篇
特种医学   70619篇
外国民族医学   242篇
外科学   297915篇
综合类   39754篇
现状与发展   75篇
一般理论   610篇
预防医学   133390篇
眼科学   44039篇
药学   126800篇
  7篇
中国医学   4514篇
肿瘤学   112689篇
  2021年   15815篇
  2020年   13494篇
  2019年   15811篇
  2018年   26957篇
  2017年   22125篇
  2016年   24401篇
  2015年   26826篇
  2014年   40594篇
  2013年   52966篇
  2012年   59569篇
  2011年   62476篇
  2010年   43179篇
  2009年   44419篇
  2008年   58724篇
  2007年   60562篇
  2006年   63228篇
  2005年   58144篇
  2004年   55603篇
  2003年   51944篇
  2002年   50290篇
  2001年   95436篇
  2000年   96500篇
  1999年   80130篇
  1998年   23480篇
  1997年   20673篇
  1996年   20656篇
  1995年   19808篇
  1994年   17189篇
  1993年   15688篇
  1992年   58781篇
  1991年   56672篇
  1990年   54071篇
  1989年   51972篇
  1988年   47206篇
  1987年   45818篇
  1986年   43187篇
  1985年   40783篇
  1984年   30094篇
  1983年   25582篇
  1982年   14611篇
  1979年   25938篇
  1978年   18015篇
  1977年   15380篇
  1976年   14203篇
  1975年   14910篇
  1974年   17951篇
  1973年   17251篇
  1972年   16034篇
  1971年   14702篇
  1970年   13707篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  相似文献   
13.
14.
15.
16.
ABSTRACT

The lack of stable housing can impair access and continuity of care for patients living with human immunodeficiency virus (HIV). This study investigated the relationship between housing status assessed at multiple time points and several core HIV-related outcomes within the same group of HIV patients experiencing homelessness. Patients with consistently stable housing (CSH) during the year were compared to patients who lacked CSH (non-CSH group). The study outcomes included HIV viral load (VL), CD4 counts, and health care utilization. Multivariable and propensity weighted analyses were used to assess outcomes adjusting for potential group differences. Of 208 patients, 88 (42%) had CSH and 120 (58%) were non-CSH. Patients with CSH had significantly higher proportion of VL suppression and higher mean CD4 counts. The frequency of nurse visits in the CSH group was less than a half of that in the non-CSH group. Patients with CSH were less likely to be admitted to the medical respite facility, and if admitted, their length of stay was about a half of that for the non-CSH group. Our study findings show that patients with CSH had significantly better HIV virologic control and immune status as well as improved health care utilization.  相似文献   
17.
18.
19.
20.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  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