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   37822篇
  免费   2166篇
  国内免费   208篇
耳鼻咽喉   460篇
儿科学   1180篇
妇产科学   1041篇
基础医学   3734篇
口腔科学   1236篇
临床医学   3305篇
内科学   8109篇
皮肤病学   683篇
神经病学   2255篇
特种医学   1343篇
外国民族医学   4篇
外科学   6862篇
综合类   867篇
现状与发展   3篇
一般理论   29篇
预防医学   2513篇
眼科学   1491篇
药学   2902篇
  1篇
中国医学   273篇
肿瘤学   1905篇
  2024年   39篇
  2023年   418篇
  2022年   1066篇
  2021年   1654篇
  2020年   993篇
  2019年   1280篇
  2018年   1583篇
  2017年   1152篇
  2016年   1269篇
  2015年   1359篇
  2014年   1710篇
  2013年   2090篇
  2012年   3137篇
  2011年   3037篇
  2010年   1720篇
  2009年   1475篇
  2008年   2261篇
  2007年   2342篇
  2006年   2058篇
  2005年   1837篇
  2004年   1660篇
  2003年   1390篇
  2002年   1222篇
  2001年   396篇
  2000年   328篇
  1999年   299篇
  1998年   202篇
  1997年   136篇
  1996年   145篇
  1995年   110篇
  1994年   97篇
  1993年   77篇
  1992年   149篇
  1991年   164篇
  1990年   131篇
  1989年   126篇
  1988年   104篇
  1987年   97篇
  1986年   91篇
  1985年   117篇
  1984年   77篇
  1983年   53篇
  1982年   53篇
  1981年   55篇
  1980年   41篇
  1979年   50篇
  1978年   40篇
  1975年   35篇
  1974年   36篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
41.
Dates are commonly consumed, especially in the Middle East, but their effect on gastrointestinal transit (GIT) has not been quantified. The effect of water and ethanol extracts from date flesh and date pits on the GIT in mice was studied. Fasted unanaesthetized male mice received by gavage either the vehicle (0.02 m/kg), or the extracts at doses of 0.01, 0.02 or 0.04 ml/kg. Two separate groups received either clonidine (1 mg/kg) or yohimbine (2 mg/kg). Two hours later, all animals were given a test meal containing charcoal and gum arabic in water. Thirty min thereafter, they were killed and the distance the charcoal column had traveled along the small intestine was measured. Compared with the control, the animals that received the ethanol and water extracts of both date flesh and pits emptied, in a dose-dependent manner, more of their gastrointestinal content. The increase in the GIT ranged from 4 to 22%. However, water extract from dialyzed date flesh induced a dose-dependent decrease in GIT that ranged from 4 to 24%. Clonidine exerted a significant decrease (68%), and yohimbine a significant increase (30%) in the GIT. Depending on the method of extraction, the date extracts may exert an increase or a decrease in GIT.  相似文献   
42.
Flow-directed pulmonary artery catheters provide important information regarding intravascular volume status, cardiac function and vascular resistance. We describe an unusual complication of pulmonary artery catheterization in which a knot formed at the distal end was torn away from the catheter body and migrated from its original position in the right subclavian vein to a distal branch of the right pulmonary artery. Careful attention to insertion and withdrawal techniques could prevent this potentially serious complication.  相似文献   
43.
44.
45.
Idiopathic bilateral adrenal hemorrhage with thrombosis of both renal veins and inferior vena cava are presented using US and CT in a newborn. To our knowledge such bilateral involvement of the adrenal glands and the renal veins have not been reported previously.  相似文献   
46.
Ten patients with complex non-union of the tibia were treated by locked intramedullary nailing. These patients had scarred skin as a result of initial severe open fractures, multiple debridement or fasciotomies with external fixators and skin grafts applied. Seven of the patients also had previous osteomyelitis or pin track infections. Fully pain-free walking was achieved in all patients and radiological union in nine patients without the need for a bone graft. Four patients developed infection after nailing, of which three resolved with treatment.  相似文献   
47.
48.
INTRODUCTION: Reconstructive septorhinoplasty in complex nasal deformities often requires harvesting a large amount of tissue for grafting. Autogenous septal cartilage has generally been considered the gold standard grafting material. The aim of this paper was to report our experience with the use of costal cartilage grafts in cases with significant structural deformities and insufficient septal cartilage. DESIGN: Retrospective chart review. PATIENTS: Between 1998 and 2006, 37 patients underwent septorhinoplasty using costal cartilage as the primary source for grafting. Twenty-two men and 14 women with a median age of 42 were enrolled in the study. Patient demographics, indications for surgery, and immediate and late complications were reviewed. The follow-up range was 3 to 72 months. CONCLUSIONS: Autogenous costal cartilage graft is a viable option in reconstructive septorhinoplasty. We advocate the use of this graft in septorhinoplasty cases requiring a large volume of tissue and insufficient septal cartilage.  相似文献   
49.
Summary A recombinant vaccinia virus designated VgBt which expresses a truncated secreted herpes simplex virus gB (gBt) was constructed and compared to V11gB, a vaccinia recombinant previously studied which expresses gB exclusively on the surface of infected cells. Indirect immunofluorescence assay (IFA) revealed that gBt was strongly associated with the surface of infected cells despite being released slowly into the cell culture medium. Both gB and gBt existed as oligomers, and both membrane bound and secreted forms of gBt exhibited heparin-binding activity. In protection studies VgBt and V11gB conferred equivalent protection against both homologous (HSV-1) and heterologous (HSV-2) challenge with HSV.  相似文献   
50.
A new dimeric indoline alkaloid has been isolated from the leaves of PETCHIA CEYLANICA. Its structure has been assigned as 1 on the basis of spectral studies. Its stereochemistry has been established by NOE difference measurements.  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