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   2319741篇
  免费   178391篇
  国内免费   3675篇
耳鼻咽喉   32095篇
儿科学   71614篇
妇产科学   64134篇
基础医学   329641篇
口腔科学   70093篇
临床医学   203763篇
内科学   451760篇
皮肤病学   49255篇
神经病学   184904篇
特种医学   92305篇
外国民族医学   541篇
外科学   360577篇
综合类   53789篇
现状与发展   3篇
一般理论   754篇
预防医学   171367篇
眼科学   53502篇
药学   177307篇
  6篇
中国医学   4705篇
肿瘤学   129692篇
  2018年   21543篇
  2016年   18747篇
  2015年   21658篇
  2014年   29814篇
  2013年   44939篇
  2012年   61073篇
  2011年   64203篇
  2010年   37930篇
  2009年   36319篇
  2008年   61932篇
  2007年   65291篇
  2006年   66523篇
  2005年   64566篇
  2004年   63262篇
  2003年   60609篇
  2002年   59406篇
  2001年   115792篇
  2000年   120030篇
  1999年   101323篇
  1998年   26084篇
  1997年   23546篇
  1996年   23528篇
  1995年   22635篇
  1994年   21129篇
  1993年   19798篇
  1992年   81821篇
  1991年   79136篇
  1990年   77084篇
  1989年   74813篇
  1988年   69030篇
  1987年   67850篇
  1986年   64160篇
  1985年   61988篇
  1984年   45497篇
  1983年   39055篇
  1982年   22081篇
  1981年   19605篇
  1980年   18250篇
  1979年   42576篇
  1978年   29160篇
  1977年   24805篇
  1976年   22781篇
  1975年   24456篇
  1974年   29761篇
  1973年   28545篇
  1972年   26487篇
  1971年   24959篇
  1970年   23283篇
  1969年   21869篇
  1968年   19936篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
AIM: The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits. METHODS: Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded. RESULTS: Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure. CONCLUSIONS: A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.  相似文献   
92.
Many recent efforts in the field of community psychology have been dedicated to moving from values to action in incorporating diversity into our work. An essential aspect of this goal is designing research that provides opportunities for underrepresented perspectives to be heard. The voices of refugee women, in particular, are not typically incorporated in research, planning for service provision, and policy design. This article explores methodological challenges involved in conducting research with refugee women who are marginalized both within broader U.S. contexts and within their own communities. Six guiding principles are presented: 1) develop strategies for involving marginalized refugee women; 2) consider the advantages and limitations of quantitative and qualitative methodologies and be innovative about combining them; 3) prepare for extensive time and effort for quantitative measure construction; 4) consider gendered decision‐making structures in the lives of refugee women and their potential impact on the research process; 5) plan for refugee women's common triple burden of working outside of the home, managing their households, and adjusting to life in a new country; and 6) attend to refugee women's cultural norms about and unfamiliarity with the interview process. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 721–739, 2004.  相似文献   
93.
94.
95.
96.
97.
98.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
99.
100.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  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