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   1684篇
  免费   371篇
  国内免费   29篇
耳鼻咽喉   8篇
儿科学   53篇
妇产科学   50篇
基础医学   151篇
口腔科学   50篇
临床医学   246篇
内科学   380篇
皮肤病学   10篇
神经病学   53篇
特种医学   16篇
外科学   118篇
综合类   58篇
预防医学   369篇
眼科学   45篇
药学   90篇
中国医学   6篇
肿瘤学   381篇
  2024年   1篇
  2023年   16篇
  2022年   37篇
  2021年   55篇
  2020年   64篇
  2019年   216篇
  2018年   152篇
  2017年   102篇
  2016年   92篇
  2015年   135篇
  2014年   225篇
  2013年   240篇
  2012年   149篇
  2011年   105篇
  2010年   89篇
  2009年   90篇
  2008年   72篇
  2007年   59篇
  2006年   49篇
  2005年   37篇
  2004年   25篇
  2003年   11篇
  2002年   13篇
  2001年   3篇
  2000年   3篇
  1999年   1篇
  1998年   3篇
  1997年   3篇
  1996年   2篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1980年   1篇
  1979年   6篇
  1978年   4篇
  1977年   2篇
  1976年   4篇
  1975年   2篇
  1974年   1篇
排序方式: 共有2084条查询结果,搜索用时 15 毫秒
61.
BackgroundIran has developed the most robust harm reduction infrastructure in the Middle East, marked by availability of low threshold methadone maintenance treatment (MMT), needle and syringe program (NSPs), and condom distribution services. However, little is known about the socially situated risk factors that make harm reduction clients—specifically those enrolled in MMT—vulnerable to relapse or continued illicit drug use. In this study, we sought to understand the “risk environment” of clients enrolled in harm reduction services in Tehran, Iran.MethodsThrough observation and in-depth interviews with 22 drop-in-center clients and 8 staff members from July to August 2017, we explored the risk environments of clients of two drop in centers (DICs) in Tehran. All interviews were transcribed, coded and analyzed using a qualitative thematic analysis.ResultsWe found that compulsory drug treatment programs, social stigma, police encounters, and difficulties in obtaining governmental identification documents, among other factors, contribute to social marginalization of DIC clients.ConclusionMany interviewed DIC clients continued to use illicit substances (particularly methamphetamine) despite having access to methadone treatment. This study underscores the panoply of social and structural barriers that DIC clients face while attempting to engage in treatment and harm reduction services. Following the “risk environment” framework, it is essential to identify the structural factors shaping individual behaviors that perpetuate experiences of social marginalization and poor health outcomes in this population.  相似文献   
62.
BackgroundDetermining prognosis in community acquired pneumonia (CAP), is very important. Many scores are introduced up to now for prediction of pneumonia prognosis like SMART-COP.ObjectiveTo evaluate validity of SMART-COP score in prognosis and severity of CAP in emergency department (ED).MethodsAll patients older than 18 years old with clinical suspicion of CAP (meeting the inclusion criteria), were enrolled in our study. In this prospective study, patients were admitted to the ED of a tertiary referral center. Hospital length of stay, rate of intensive care unit (ICU) admission, mortality rate, number of intensive respiratory or vasopressor support (IRVS) use, patients' SMART-COP scores and all demographic data were recorded. Validity of SMART-COP in the prediction of IRVS rate and its correlation with other variables were determined.ResultsIn this study, 47.6% and 52.4% of patients were females and males respectively. The mean age of patients was 68.13 ± 16.60 years old. The mean hospital length of stay was 13.49 ± 5.62 days. Of all patients entered in our study, 55 cases (38.5%) needed ICU admission, 29 cases (20.3%) were expired within 1 month and 44 cases (30.8%) needed IRVS during their treatment. SMART-COP ≥5 (high risk CAP) accurately predicted the rate of ICU admission, one-month mortality and IRVS need (p-value = 0.001).ConclusionsSMART-COP≥5 had a high sensitivity and specificity in the prediction of patients' prognosis with severe CAP in the ED.  相似文献   
63.
64.
65.
66.
67.
Exposure to cigarette smoke is emerging as an environmental risk factor for multiple sclerosis (MS). We investigated the possible association between environmental tobacco smoke, its cumulative exposure, and MS risk. We used data from the Iranian Multiple Sclerosis Registry to identify a case-control of 662 patients who had MS and a comparison group of 394 patients. Information regarding current smoking status, including the number of cigarettes smoked per day, duration, and smoking pack-years indicative of cumulative dose of tobacco smoked was obtained. We analyzed the incidence of MS among ever–smokers who had been smokers during their disease course and prior to disease onset in comparison with never–smokers who had never been exposed by calculating the odds ratio (OR) with a 95% confidence interval (CI) employing logistic regression. Of the 662 MS patients, there were 523 women (79.0%) and 139 men (21.0%), with a mean age of 31 ± 10.0 years at disease onset. The risk for MS was increased among ever–smokers (OR = 1.78, 95% CI = 1.22–2.59, p = 0.03) compared to never–smokers. As compared with never smokers, the OR for patients with 6–10 pack years was 2.91 for men (95% CI = 1.11–9.47, p = 0.03) and 1.69 for women (95% CI = 1.02–6.45, p = 0.04). Our results demonstrate that cigarette smoking is significantly associated with an increased risk for MS. The risk effects of smoking were more noticeable in male patients and at higher tobacco doses.  相似文献   
68.
69.
70.
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