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   56132篇
  免费   3408篇
  国内免费   668篇
耳鼻咽喉   967篇
儿科学   800篇
妇产科学   851篇
基础医学   9641篇
口腔科学   1394篇
临床医学   4977篇
内科学   10484篇
皮肤病学   1903篇
神经病学   3915篇
特种医学   3297篇
外科学   7502篇
综合类   250篇
现状与发展   1篇
一般理论   17篇
预防医学   2610篇
眼科学   1216篇
药学   4975篇
  2篇
中国医学   620篇
肿瘤学   4786篇
  2023年   302篇
  2022年   206篇
  2021年   1689篇
  2020年   999篇
  2019年   1302篇
  2018年   1696篇
  2017年   1262篇
  2016年   1779篇
  2015年   2598篇
  2014年   3105篇
  2013年   3544篇
  2012年   5346篇
  2011年   4842篇
  2010年   2890篇
  2009年   2443篇
  2008年   3465篇
  2007年   3180篇
  2006年   2701篇
  2005年   2405篇
  2004年   2046篇
  2003年   1701篇
  2002年   1453篇
  2001年   1394篇
  2000年   1278篇
  1999年   925篇
  1998年   448篇
  1997年   377篇
  1996年   323篇
  1995年   283篇
  1994年   261篇
  1993年   229篇
  1992年   359篇
  1991年   350篇
  1990年   315篇
  1989年   310篇
  1988年   293篇
  1987年   290篇
  1986年   226篇
  1985年   210篇
  1984年   145篇
  1983年   126篇
  1982年   79篇
  1981年   86篇
  1980年   66篇
  1979年   85篇
  1978年   76篇
  1977年   57篇
  1976年   70篇
  1975年   64篇
  1974年   60篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
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   
3.
4.
Graefe's Archive for Clinical and Experimental Ophthalmology - To compare visual outcomes between two types of mix-and-match implanted trifocal extended-depth-of-focus (EDoF) and trifocal...  相似文献   
5.
6.
Social Psychiatry and Psychiatric Epidemiology - The negative effect of catastrophic financial loss on suicide risk is widely perceived but hardly studied in-depth because of various difficulties...  相似文献   
7.
International Journal of Clinical Oncology - Previous studies have shown a relationship between the occurrence and recurrence of prostate cancer; however, this relationship remains controversial....  相似文献   
8.
9.
10.

Background

It has been reported that particulate matter (PM) is associated with cardiovascular diseases (CVD) while metabolic syndrome is also an important risk factor for CVD. However, few studies have investigated the epidemiological association between PM and metabolic syndrome.

Objective

To investigate the association between one-year exposure to PM with an aerodynamic diameter <2.5?μm (PM2.5) and the risk of metabolic syndrome in Korean adults without CVD.

Methods

Exposure to PM2.5 was assessed using a Community Multiscale Air Quality (CMAQ) model. Metabolic syndrome was defined by National Cholesterol Education Program Adult Treatment Panel III. Andersen and Gill model with time-varying covariates, considering recurrent events, was used to investigate the association between one-year average PM2.5 and the risk of incident metabolic syndrome in 119,998 adults from the national health screening cohort provided by Korea National Health Insurance from 2009 to 2013.

Results

Higher risk of metabolic syndrome, waist-based obesity, hypertension, hypertriglyceridemia, low HDL cholesterol, and hyperglycemia were significantly associated with a 10-μg/m3 increase in PM2.5 [adjusted hazard ratio (HR): 1.070, 1.510, 1.499, 1.468, 1.627 and 1.380, respectively]. In addition, the risk of metabolic syndrome associated with PM2.5 exposure was significant in the consistently obese group (obese at baseline and endpoint).

Conclusion

Exposure to one-year average PM2.5 is associated with an increased risk of metabolic syndrome and its components in adults without CVD. These associations are particularly prominent in the consistently obese group (obese at baseline and endpoint). Our findings indicate that PM2.5 affects the onset of MS and its components which may lead to increase the risk of CVD.  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