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   2476213篇
  免费   196924篇
  国内免费   5330篇
耳鼻咽喉   36314篇
儿科学   80443篇
妇产科学   64729篇
基础医学   350901篇
口腔科学   65029篇
临床医学   234394篇
内科学   496119篇
皮肤病学   58305篇
神经病学   197451篇
特种医学   93368篇
外国民族医学   493篇
外科学   387928篇
综合类   47780篇
现状与发展   84篇
一般理论   848篇
预防医学   188485篇
眼科学   57286篇
药学   176053篇
  11篇
中国医学   4592篇
肿瘤学   137854篇
  2021年   21569篇
  2019年   21305篇
  2018年   33261篇
  2017年   26476篇
  2016年   29571篇
  2015年   32550篇
  2014年   48969篇
  2013年   67076篇
  2012年   79282篇
  2011年   84092篇
  2010年   55758篇
  2009年   56407篇
  2008年   79505篇
  2007年   82946篇
  2006年   85785篇
  2005年   81029篇
  2004年   76989篇
  2003年   73391篇
  2002年   71137篇
  2001年   111895篇
  2000年   113981篇
  1999年   96151篇
  1998年   29978篇
  1997年   26469篇
  1996年   26735篇
  1995年   25329篇
  1994年   22433篇
  1993年   20956篇
  1992年   73107篇
  1991年   71237篇
  1990年   69266篇
  1989年   66608篇
  1988年   61123篇
  1987年   59849篇
  1986年   55957篇
  1985年   53593篇
  1984年   39756篇
  1983年   33819篇
  1982年   20279篇
  1979年   36110篇
  1978年   25918篇
  1977年   21548篇
  1976年   20533篇
  1975年   22047篇
  1974年   26328篇
  1973年   25003篇
  1972年   23461篇
  1971年   22186篇
  1970年   20453篇
  1969年   19375篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
141.
142.
The severity of illness in transplant patients and the complexity of transplant operations results in significant postoperative morbidity and mortality. Remarkable efforts have been made by transplant physicians to study and improve organ allocation, graft and patient survival, immunosuppression and the long-term management of post-transplant complications. Less effort has been spent studying the actual transplant operation and systems of acute transplant care. The National Surgical Quality Improvement Program (NSQIP) has provided a standardized approach to quality improvement and has demonstrated significant potential for a reduction in postoperative morbidity and mortality in other surgical disciplines. Medical centers are under increasing pressure to measure surgical quality and the nexus of transplant surgical quality improvement should not lie in the hands of CMS or JACHO, but rather it should be created and developed within the transplant community. The time has come for a national transplant surgical quality improvement program based on the NSQIP infrastructure. Such a proactive approach toward quality improvement from the transplant community is an excellent investment for patients, providers and health care payers.  相似文献   
143.
Abstract: Data from the National Education Longitudinal Study were combined with census data at the zip code level to examine the impact of neighborhood racial and ethnic diversity and consolidated inequality, in addition to individual, family, and school factors, on the likelihood of dropping out of high school. Results indicate that while the effects for diversity and consolidated inequality did not support the stated hypotheses, main effects for family risk and prior academic achievement were significant and in the stated direction. Also, when controlling for individual, family, school, and neighborhood characteristics, African Americans were less likely than White students to drop out of school. Implications for contextual effects research and educational outcomes are discussed.  相似文献   
144.
Anxiety disorders and anxiety symptoms are highly prevalent in the general population and more so in the medically ill. They have a number of negative consequences for these patients and may worsen the outcome of the medical illness and increase health care utilization. In the evaluation of these patients, it is of paramount importance to identify the etiology of the anxiety and, in particular, to differentiate primary from secondary anxiety. Management includes medications (especially benzodiazepines and selective serotonin reuptake inhibitors) and psychotherapy (particularly cognitive-behavioral therapy).  相似文献   
145.
146.
OBJECTIVE: To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life. METHODS: This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers. RESULTS: In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted. CONCLUSIONS: RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations.  相似文献   
147.
148.
Vacuum-assisted closure (VAC), although a modern adjunct in wound management, has not been used previously in pyoderma gangrenosum (PG), probably to avoid the potential complications of ‘pathergy’. We would like to report our experience of VAC in three cases of PG with the relevant review of literature.  相似文献   
149.
150.
Wound healing involves a number of cellular and molecular events, many of which are controlled by soluble growth factors. In the process of healing, hepatocyte growth factor, a cytokine known to act as mitogen, motogen, and morphogen, has been postulated to play multiple roles during several stages of this complex biological process. Produced primarily by stromal fibroblasts, hepatocyte growth factor regulates angiogenesis, vascular permeability, cell migration, matrix deposition and degradation, and other biological processes. The current article discusses recent progress in understanding the multiple roles played by this growth factor in tissue repair.  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