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   3191693篇
  免费   248268篇
  国内免费   5473篇
耳鼻咽喉   45423篇
儿科学   100167篇
妇产科学   86308篇
基础医学   457906篇
口腔科学   91819篇
临床医学   295356篇
内科学   617275篇
皮肤病学   66014篇
神经病学   265395篇
特种医学   124724篇
外国民族医学   1104篇
外科学   471540篇
综合类   73765篇
现状与发展   4篇
一般理论   1435篇
预防医学   262225篇
眼科学   75215篇
药学   237616篇
  10篇
中国医学   5741篇
肿瘤学   166392篇
  2018年   32876篇
  2016年   27917篇
  2015年   31738篇
  2014年   45224篇
  2013年   69083篇
  2012年   93288篇
  2011年   98929篇
  2010年   58035篇
  2009年   55639篇
  2008年   93892篇
  2007年   100133篇
  2006年   100506篇
  2005年   98127篇
  2004年   94371篇
  2003年   91000篇
  2002年   89504篇
  2001年   142966篇
  2000年   147518篇
  1999年   124935篇
  1998年   36532篇
  1997年   33103篇
  1996年   33138篇
  1995年   31721篇
  1994年   29819篇
  1993年   27895篇
  1992年   100955篇
  1991年   98156篇
  1990年   94920篇
  1989年   91564篇
  1988年   85172篇
  1987年   83713篇
  1986年   79588篇
  1985年   75893篇
  1984年   57671篇
  1983年   49812篇
  1982年   30145篇
  1981年   26992篇
  1980年   25378篇
  1979年   54635篇
  1978年   38971篇
  1977年   32802篇
  1976年   30696篇
  1975年   32659篇
  1974年   40088篇
  1973年   38534篇
  1972年   36351篇
  1971年   33719篇
  1970年   31717篇
  1969年   29671篇
  1968年   27222篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.  相似文献   
3.
4.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
5.
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   
6.
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   
7.

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   
8.
9.
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