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   2374767篇
  免费   183893篇
  国内免费   4505篇
耳鼻咽喉   31749篇
儿科学   78672篇
妇产科学   67961篇
基础医学   345440篇
口腔科学   66136篇
临床医学   218331篇
内科学   463170篇
皮肤病学   53667篇
神经病学   193720篇
特种医学   89742篇
外国民族医学   702篇
外科学   347021篇
综合类   53503篇
一般理论   973篇
预防医学   192163篇
眼科学   54312篇
药学   171161篇
  7篇
中国医学   4780篇
肿瘤学   129955篇
  2018年   26337篇
  2017年   20166篇
  2016年   22468篇
  2015年   25380篇
  2014年   35989篇
  2013年   54429篇
  2012年   73878篇
  2011年   78743篇
  2010年   46033篇
  2009年   44049篇
  2008年   73381篇
  2007年   78158篇
  2006年   78163篇
  2005年   76093篇
  2004年   73077篇
  2003年   69666篇
  2002年   67481篇
  2001年   111785篇
  2000年   114041篇
  1999年   94799篇
  1998年   25446篇
  1997年   22908篇
  1996年   23216篇
  1995年   23557篇
  1994年   21674篇
  1993年   20259篇
  1992年   73825篇
  1991年   71733篇
  1990年   69091篇
  1989年   66546篇
  1988年   61337篇
  1987年   59981篇
  1986年   56568篇
  1985年   53755篇
  1984年   40987篇
  1983年   35209篇
  1982年   21114篇
  1981年   19088篇
  1979年   37569篇
  1978年   27134篇
  1977年   22534篇
  1976年   21070篇
  1975年   22222篇
  1974年   27019篇
  1973年   26374篇
  1972年   24899篇
  1971年   22943篇
  1970年   21683篇
  1969年   20326篇
  1968年   19099篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
ObjectiveTo determine prognostic factors and survival patterns for different treatment modalities for nasal cavity (NC) and paranasal sinus (PS) mucosal melanoma (MM).MethodsPatients from 1973 to 2013 were analyzed using the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier method and multivariable cox proportional hazard modeling were used for survival analyses.ResultsOf 928 cases of mucosal melanoma (NC = 632, PS = 302), increasing age (Hazard Ratio [HR]:1.05/year, p < 0.001), T4 tumors (HR: 1.81, p = 0.02), N1 status (HR: 6.61, p < 0.001), and PS disease (HR: 1.50, p < 0.001) were associated with worse survival. Median survival length was lower for PS versus NC (16 versus 26 months, p < 0.001). Surgery and surgery + radiation therapy (RT) improved survival over non-treatment or RT alone (p < 0.001). Adding RT to surgery did not yield a survival difference compared with surgery alone (p = 0.43). Five-year survival rates for surgery and surgery + RT were similar, at 27.7% and 25.1% (p = 0.43).ConclusionSurgery increased survival significantly over RT alone. RT following surgical resection did not improve survival.  相似文献   
2.
3.
Modified-release opioids are often prescribed for the management of moderate to severe acute pain following total hip and knee arthroplasty, despite recommendations against their use due to increasing concerns regarding harm. The primary objective of this multicentre study was to examine the impact of modified-release opioid use on the incidence of opioid-related adverse events compared with immediate-release opioid use, among adult inpatients following total hip or knee arthroplasty. Data for total hip and knee arthroplasty inpatients receiving an opioid analgesic for postoperative analgesia during hospitalisation were collected from electronic medical records of three tertiary metropolitan hospitals in Australia. The primary outcome was the incidence of opioid-related adverse events during hospital admission. Patients who received modified with or without immediate-release opioids were matched to those receiving immediate-release opioids only (1:1) using nearest neighbour propensity score matching with patient and clinical characteristics as covariates. This included total opioid dose received. In the matched cohorts, patients given modified-release opioids (n = 347) experienced a higher incidence of opioid-related adverse events overall, compared with those given immediate-release opioids only (20.5%, 71/347 vs. 12.7%, 44/347; difference in proportions 7.8% [95%CI 2.3–13.3%]). Modified-release opioid use was associated with an increased risk of harm when used for acute pain during hospitalisation after total hip or knee arthroplasty.  相似文献   
4.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia.  相似文献   
5.
6.
AIDS and Behavior - Transactional sex increases HIV risk among adolescent girls and young women (AGYW). Understanding the individual and dyadic nature of transactional sex may provide evidence for...  相似文献   
7.
Journal of Interventional Cardiac Electrophysiology - Atrial fibrillation is associated with an increased risk of cognitive impairment. It is unclear whether the restoration of sinus rhythm with...  相似文献   
8.
Pharmaceutical Research - The quality testing and approval procedure for most pharmaceutical products is a streamlined process with standardized procedures for the determination of critical quality...  相似文献   
9.
Graefe's Archive for Clinical and Experimental Ophthalmology - To investigate comorbidities and medications associated with acute (ASCH) and delayed (DSCH) suprachoroidal hemorrhage (SCH), and...  相似文献   
10.
Pharmaceutical Chemistry Journal - Metformin hydrochloride is widely used to treat diabetes mellitus. This review presents its physical and chemical properties and discusses methods of analysis...  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