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   3169篇
  免费   188篇
  国内免费   86篇
耳鼻咽喉   16篇
儿科学   145篇
妇产科学   234篇
基础医学   355篇
口腔科学   39篇
临床医学   453篇
内科学   616篇
皮肤病学   77篇
神经病学   238篇
特种医学   359篇
外国民族医学   1篇
外科学   325篇
综合类   42篇
一般理论   2篇
预防医学   136篇
眼科学   84篇
药学   173篇
中国医学   2篇
肿瘤学   146篇
  2022年   18篇
  2021年   34篇
  2020年   17篇
  2019年   42篇
  2018年   55篇
  2017年   34篇
  2016年   34篇
  2015年   46篇
  2014年   55篇
  2013年   85篇
  2012年   110篇
  2011年   102篇
  2010年   116篇
  2009年   81篇
  2008年   98篇
  2007年   123篇
  2006年   100篇
  2005年   108篇
  2004年   83篇
  2003年   72篇
  2002年   74篇
  2001年   69篇
  2000年   91篇
  1999年   79篇
  1998年   117篇
  1997年   110篇
  1996年   126篇
  1995年   98篇
  1994年   100篇
  1993年   102篇
  1992年   40篇
  1991年   78篇
  1990年   58篇
  1989年   86篇
  1988年   68篇
  1987年   72篇
  1986年   72篇
  1985年   75篇
  1984年   38篇
  1983年   37篇
  1982年   38篇
  1981年   27篇
  1980年   28篇
  1979年   41篇
  1978年   27篇
  1977年   32篇
  1976年   22篇
  1975年   27篇
  1973年   19篇
  1969年   16篇
排序方式: 共有3443条查询结果,搜索用时 437 毫秒
1.
2.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
3.
European Journal of Orthopaedic Surgery & Traumatology - The goals of this study were to compare patient satisfaction and wound-related complications in patients receiving 2-octyl cyanoacrylate...  相似文献   
4.
C31G, which has potent activity against the human immunodeficiency virus type 1 (HIV-1) and an established record of safety in animal studies and human trials, is a microbicidal agent comprised of a buffered equimolar mixture of two amphoteric, surface-active agents: an alkyl amine oxide (C14AO) and an alkyl betaine (C16B). Studies of long-term in vitro exposure to C31G and its constituents have suggested that the components of C31G may contribute differentially to its toxicity and efficacy. In the present studies, in vitro assays of cytotoxicity and anti-HIV-1 activity demonstrated that C16B was slightly less cytotoxic compared to either C31G or C14AO, whereas the anti-HIV-1 activities of C31G and its individual constituents were similar. In the murine model of cervicovaginal microbicide toxicity, in vivo exposure to C14AO resulted in severe cervical inflammation followed by a delayed disruption of the columnar epithelium. In contrast, exposure to C16B caused severe cervical epithelial disruption and a secondary, less intense inflammatory response. These results demonstrate that (i) there are both mechanistic and temporal differences in toxicity associated with the components of C31G not necessarily predicted by in vitro assessments of cytotoxicity and (ii) contributions of each component to the anti-HIV-1 activity of C31G appear to be equal. In addition, these findings indicate that direct and indirect mechanisms of in vivo toxicity can be observed as separate but interrelated events. These results provide further insight into the activity of C31G, as well as mechanisms potentially associated with microbicide toxicity.  相似文献   
5.
6.
7.
Background: Sudden, intraoperative cardiovascular deterioration as a result of pulmonary embolization of bone marrow fat is a potentially fatal complication during total hip and knee arthroplasty, intramedullary nailing, and spine surgery. Anesthetic management is challenging in the presence of increased right ventricular afterload due to pulmonary hypertension. Selective pulmonary vasodilation may be an appropriate prophylactic or therapeutic measure. The effect of sildenafil (phosphodiesterase inhibitor) on cardiovascular deterioration after bone marrow fat embolization was therefore investigated.

Methods: Bone cement (polymethylmethacrylate) was injected into three lumbar vertebrae in 12 sheep. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output and arterial and mixed venous blood gas variables were measured at selected time points. Before the first cement injection, 6 animals received a bolus injection (0.7 mg/kg) of sildenafil, with continuous infusion (0.2 mg [middle dot] kg-1 [middle dot] h-1) thereafter. Postmortem lung and kidney biopsies were taken for semiquantitative analysis of intravascular fat.

Results: Fat embolism was associated with a transient increase (21 +/- 7mmHg) in pulmonary arterial pressure. A transient decrease in arterial blood pressure and temporary increases in central venous pressure and dead space were also observed. No significant changes in any cardiovascular variable were observed after fat embolism in the sildenafil group. There was significantly (P < 0.05) less intravascular fat in the lungs of the sildenafil (median count of 5 emboli per microscopic view) compared with the control group (median count of 1).  相似文献   

8.
9.
The influence of such individual characteristics as age, sex, morphological characteristics (CDD angle, length of femoral neck, total and medullary diameter and score on the Singh osteoporosis index) on the loading capacity and deformation of the proximal end of the femur were determined in this experimental study. In all, 341 femora taken from the cadavers of persons who had died at over 60 years of age were tested under alternating load in up to 4000 cycles and, if no instability occurred, also under static load. The loading capacity and deformation were compared. The loading capacity was significantly higher in male femora with (5441 +/- 257 N) than in female femora (4273 +/- 1850 N). The loading capacity also decreased with increasing age and with decreasing CCD angle and Singh index score (higher degree of osteoporosis). Because of the high standard deviation in each group these differences were not significant.  相似文献   
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