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   5398247篇
  免费   409119篇
  国内免费   16220篇
耳鼻咽喉   77719篇
儿科学   171073篇
妇产科学   144103篇
基础医学   798679篇
口腔科学   152388篇
临床医学   497313篇
内科学   981066篇
皮肤病学   125235篇
神经病学   445648篇
特种医学   211184篇
外国民族医学   1292篇
外科学   814177篇
综合类   152515篇
现状与发展   23篇
一般理论   2981篇
预防医学   456698篇
眼科学   130247篇
药学   384975篇
  29篇
中国医学   13782篇
肿瘤学   262459篇
  2021年   56936篇
  2019年   59386篇
  2018年   76903篇
  2017年   58866篇
  2016年   65652篇
  2015年   77611篇
  2014年   112550篇
  2013年   178149篇
  2012年   154502篇
  2011年   165369篇
  2010年   135080篇
  2009年   133514篇
  2008年   150753篇
  2007年   162932篇
  2006年   169601篇
  2005年   164426篇
  2004年   164076篇
  2003年   153588篇
  2002年   143398篇
  2001年   209421篇
  2000年   207673篇
  1999年   185510篇
  1998年   78226篇
  1997年   72196篇
  1996年   70115篇
  1995年   65788篇
  1994年   59748篇
  1993年   55293篇
  1992年   139105篇
  1991年   135054篇
  1990年   130225篇
  1989年   126274篇
  1988年   117048篇
  1987年   114944篇
  1986年   108756篇
  1985年   106236篇
  1984年   85406篇
  1983年   75081篇
  1982年   54619篇
  1981年   50470篇
  1980年   47336篇
  1979年   77536篇
  1978年   59836篇
  1977年   51777篇
  1976年   48861篇
  1975年   49936篇
  1974年   57606篇
  1973年   55208篇
  1972年   52117篇
  1971年   48374篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Gattermann  J. 《Der Onkologe》2020,26(11):1010-1018
Die Onkologie - Die Corona-Pandemie hat in den letzten Monaten verdeutlicht, dass das Thema Sterblichkeit trotz erheblicher Fortschritte im Bereich der Hospiz- und Palliativversorgung zu...  相似文献   
32.
Bulletin of Experimental Biology and Medicine - Ammonium, an end-product of catabolism, in low doses can promote adaptation of metabolic pathways in erythrocytes under conditions of extreme...  相似文献   
33.
Introduction: Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype associated with an increased risk of recurrence and cancer-related death. Unlike hormone receptor-positive or HER2-positive breast cancers, there are limited targeted therapies available to treat TNBC and cytotoxic chemotherapy remains the mainstay of treatment. Sacituzumab govitecan (IMMU-132) is an antibody-drug conjugate targeting Trop-2 expressing cells and selectively delivering SN-38, an active metabolite of irinotecan.

Areas covered: This review covers the mechanism of action, safety and efficacy of sacituzumab govitecan in patients with previously treated, metastatic TNBC. Additionally, efficacy data in other epithelial malignancies is included based on a PubMed search for ‘sacituzumab govitecan’ and ‘clinical trial’.

Expert opinion: Sacituzumab govitecan has promising anti-cancer activity in patients with metastatic TNBC previously treated with at least two prior lines of systemic therapy based on a single arm Phase I/II clinical trial. A confirmatory Phase III randomized clinical trial is ongoing. Sacituzumab govitecan has a manageable side effect profile, with the most common adverse events being nausea, neutropenia, and diarrhea. The activity of sacituzumab govitecan likely extends beyond TNBC with promising early efficacy data in many other epithelial cancers, including hormone receptor-positive breast cancer.  相似文献   

34.
The majority of hip fractures in the elderly are the result of a fall from standing or from a lower height. Current injury models focus mostly on femur strength while neglecting subject-specific loading. This article presents an injury modeling strategy for hip fractures related to sideways falls that takes subject-specific impact loading into account. Finite element models (FEMs) of the human body were used to predict the experienced load and the femoral strength in a single model. We validated these models for their predicted peak force, effective pelvic stiffness, and fracture status against matching ex vivo sideways fall impacts (n = 11) with a trochanter velocity of 3.1 m/s. Furthermore, they were compared to sideways impacts of volunteers with lower impact velocities that were previously conducted by other groups. Good agreement was found between the ex vivo experiments and the FEMs with respect to peak force (root mean square error [RMSE] = 10.7%, R2 = 0.85) and effective pelvic stiffness (R2 = 0.92, RMSE = 12.9%). The FEMs were predictive of the fracture status for 10 out of 11 specimens. Compared to the volunteer experiments from low height, the FEMs overestimated the peak force by 25% for low BMI subjects and 8% for high BMI subjects. The effective pelvic stiffness values that were derived from the FEMs were comparable to those derived from impacts with volunteers. The force attenuation from the impact surface to the femur ranged between 27% and 54% and was highly dependent on soft tissue thickness (R2 = 0.86). The energy balance in the FEMS showed that at the time of peak force 79% to 93% of the total energy is either kinetic or was transformed to soft tissue deformation. The presented FEMs allow for direct discrimination between fracture and nonfracture outcome for sideways falls and bridge the gap between impact testing with volunteers and impact conditions representative of real life falls. © 2019 American Society for Bone and Mineral Research.  相似文献   
35.
36.

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   
37.
38.
39.
40.
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