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   12856篇
  免费   482篇
  国内免费   38篇
耳鼻咽喉   109篇
儿科学   516篇
妇产科学   2155篇
基础医学   1450篇
口腔科学   552篇
临床医学   1301篇
内科学   1794篇
皮肤病学   298篇
神经病学   660篇
特种医学   566篇
外国民族医学   4篇
外科学   1391篇
综合类   206篇
一般理论   4篇
预防医学   988篇
眼科学   303篇
药学   531篇
中国医学   85篇
肿瘤学   463篇
  2022年   126篇
  2021年   234篇
  2020年   154篇
  2019年   158篇
  2018年   265篇
  2017年   226篇
  2016年   187篇
  2015年   206篇
  2014年   256篇
  2013年   532篇
  2012年   376篇
  2011年   448篇
  2010年   326篇
  2009年   465篇
  2008年   399篇
  2007年   344篇
  2006年   376篇
  2005年   362篇
  2004年   331篇
  2003年   256篇
  2002年   216篇
  2001年   155篇
  2000年   139篇
  1999年   344篇
  1998年   305篇
  1997年   352篇
  1996年   392篇
  1995年   332篇
  1994年   283篇
  1993年   220篇
  1992年   229篇
  1991年   251篇
  1990年   197篇
  1989年   175篇
  1988年   169篇
  1987年   151篇
  1986年   173篇
  1985年   140篇
  1984年   123篇
  1983年   164篇
  1982年   109篇
  1981年   93篇
  1980年   122篇
  1979年   114篇
  1978年   80篇
  1977年   113篇
  1976年   110篇
  1975年   110篇
  1974年   82篇
  1973年   90篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Objectives

The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.

Methods

PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.

Results

Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).

Conclusions

In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550)  相似文献   
3.
Our objectives were to study the prevalence, risk factors for carriage, and transmission dynamics of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae (ESBLPE) in a national survey of cattle. This was a point prevalence study conducted from July to October 2013 in Israel. Stool samples were collected from 1,226 cows in 123 sections on 40 farms of all production types. ESBLPE were identified in 291 samples (23.7%): 287 contained Escherichia coli and 4 contained Klebsiella pneumoniae. The number of ESBLPE-positive cows was the highest in quarantine stations and on fattening farms and was the lowest on pasture farms (P = 0.03). The number of ESBLPE-positive cows was the lowest in sections containing adult cows (age, >25 months) and highest in sections containing calves (age, <4 months) (P < 0.001). Infrastructure variables that were significant risk factors for ESBLPE carriage included crowding, a lack of manure cleaning, and a lack of a cooling (P < 0.001 for each), all of which were more common in sections containing calves. Antimicrobial prophylaxis was given almost exclusively to calves and was associated with a high number of ESBLPE carriers (P < 0.001). The 287 E. coli isolates were typed into 106 repetitive extragenic palindromic (REP)-PCR types and mostly harbored blaCTX-M-1 or blaCTX-M-9 group genes. The isolates on the six farms with ≥15 isolates of ESBLPE were of 4 to 7 different REP-PCR types, with one dominant type being harbored by about half of the isolates. Fourteen types were identified on more than one farm, with only six of the farms being adjacent to each other. The prevalence of ESBLPE carriage is high in calves in cowsheds where the use of antimicrobial prophylaxis is common. ESBLPE disseminate within cowsheds mainly by clonal spread, with limited intercowshed transmission occurring.  相似文献   
4.
5.
6.
7.
8.
9.
10.
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