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   4438篇
  免费   336篇
  国内免费   16篇
耳鼻咽喉   66篇
儿科学   175篇
妇产科学   102篇
基础医学   726篇
口腔科学   110篇
临床医学   330篇
内科学   1154篇
皮肤病学   122篇
神经病学   370篇
特种医学   143篇
外科学   661篇
综合类   17篇
一般理论   3篇
预防医学   217篇
眼科学   105篇
药学   244篇
中国医学   11篇
肿瘤学   234篇
  2023年   19篇
  2022年   50篇
  2021年   120篇
  2020年   60篇
  2019年   125篇
  2018年   138篇
  2017年   79篇
  2016年   89篇
  2015年   106篇
  2014年   137篇
  2013年   179篇
  2012年   286篇
  2011年   298篇
  2010年   158篇
  2009年   156篇
  2008年   246篇
  2007年   245篇
  2006年   235篇
  2005年   239篇
  2004年   239篇
  2003年   227篇
  2002年   196篇
  2001年   183篇
  2000年   196篇
  1999年   136篇
  1998年   55篇
  1997年   45篇
  1996年   39篇
  1995年   24篇
  1994年   23篇
  1993年   20篇
  1992年   66篇
  1991年   45篇
  1990年   41篇
  1989年   30篇
  1988年   29篇
  1987年   37篇
  1986年   17篇
  1985年   19篇
  1984年   22篇
  1983年   19篇
  1982年   12篇
  1979年   12篇
  1977年   12篇
  1976年   8篇
  1975年   8篇
  1973年   6篇
  1971年   6篇
  1970年   7篇
  1968年   6篇
排序方式: 共有4790条查询结果,搜索用时 15 毫秒
71.
72.
Radio-guided surgery is a new technique which can provide benefits for pediatric oncology, as in our patient with neuroblastoma in stage IV, that after a chemotherapy, surgical, radiotherapy and autologous bone marrow transplant treatment kept showing, at 2 years, residual tumoral fragments and increase of catecholamines. Radio-guided surgery allowed an easy and exact location. This technique decreases surgery time and let us find residual tumoral tissue no matter how small. With radio-guided surgery we can obtain higher survival and even cure the patient.  相似文献   
73.
The haemodynamic changes produced by laparoscopic surgery in children have been evaluated. A transesophageal echocardiographic study on 13 patients (7 males and 6 females, 10.8 +/- 2.7 years old) has been performed before, during and after peritoneal CO2 gas insufflation. A change on the Doppler waves pattern of the infradiaphragmatic veins along with an increase in blood flow velocity were observed. Pulmonary veins suffered minimal changes showing an increase on either the systolic pressure and on atrial contraction. Diastolic retrograde flow in aorta reflected an increase in peripheral vascular resistance. Cardiac output increased minimally. All haemodynamic changes returned to basal after gas peritoneal desufflation. These data show that laparoscopic surgery could produce important cardiac derangements in children with ventricular dysfunction or in patients presenting left ventricular outlet obstruction. In these patients laparoscopic surgery might be precluded.  相似文献   
74.
75.
Gastric mucosal cell migration and proliferation are crucial events in the repair of gastric mucosal erosions. This study was designed to test the hypothesis that the H2 blockers roxatidine and ranitidine might stimulate migration and proliferation of gastric mucous cells derived from a human well-differentiated gastric adenocarcinoma cell line (MKN 28 cells)in vitro, in conditions independent of systemic factors and of acid inhibition. Confluent monolayers of MKN 28 cells were wounded with a razor blade and were then incubated with roxatidine or ranitidine. The number of cells migrating to the damaged area was determined 24 hr later. Cell proliferation was assessed by means of [3H]thymidine uptake and cell counts after incubation with roxatidine or ranitidine. Neither H2 antagonist significantly stimulated cell migration. On the other hand, cell proliferation was dose-dependently and significantly enhanced by incubation with roxatidine and ranitidine. Exogenous administration of TGF- significantly stimulated MKN 28 cell division. However, incubation with roxatidine or ranitidine did not increase the steady-state mRNA expression of TGF- or EGFR as assessed by northern blot analysis. Based on thesein vitro findings, we postulate that the ulcer healing effect of these H2 antagonistsin vivo might be due in part to stimulation of gastric mucosal cell proliferation.Data from this paper have been presented in part at the 1995 meeting of the American Gastroenterological Association and published in abstract form in Gastroenterology 108:A72, 1995.  相似文献   
76.
Over the last decade kidney transplantation has become a common therapeutic procedure for patients with end-stage renal diseases. Between 1988 and 1998 donors rate per million population has dramatically increased in our environment, thus providing us with more chances to offer kidney transplantation to a larger number of patients. The technico-surgical difficulties that have to be faced however, are increasingly frequent and require a search for new approaches and innovative changes to the usual surgical techniques for our patient's benefit.  相似文献   
77.
78.
PURPOSE: Helicobacter pylori causes gastric damage and is involved in gastric carcinogenesis. Vascular endothelial growth factor (VEGF) plays a major role in gastric mucosa repair and is overexpressed in gastric cancer. We investigated: (a) whether H. pylori, and in particular H. pylori VacA toxin, affected VEGF expression in gastric epithelial cells in culture; and (b) the signal transduction pathway involved in any effect exerted by H. pylori. EXPERIMENTAL DESIGN: MKN-28 cells were incubated with uninoculated BCF (control) or with BCF obtained from VacA-producing wild-type H. pylori 60190 strain or from its isogenic mutant 60190:v1, specifically lacking vacA gene in the presence or absence of ZD 1839, a selective inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, PD098059, a selective inhibitor of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase, the kinase responsible for ERK phosphorylation, or SC-236, a selective inhibitor of cyclooxygenase (COX)-2 for 24-48 h. RESULTS: (a) Toxigenic H. pylori up-regulated VEGF mRNA and protein expression and caused a 2.5-fold increase in VEGF release compared with control, whereas nontoxigenic H. pylori did not; (b) H. pylori VacA toxin-induced up-regulation of VEGF was counteracted by selective inhibition of EGFR tyrosine kinase; (c) toxigenic H. pylori activated the ERK/MAP kinase cascade, and inhibition of MAP kinase activation counteracted H. pylori-induced VEGF up-regulation; (d) toxigenic H. pylori up-regulated COX-2 expression, and this effect was counteracted by blockade of EGFR tyrosine kinase; and (e) COX-2 selective inhibition counteracted H. pylori-induced up-regulation of VEGF. CONCLUSION: (a) H. pylori up-regulates VEGF expression in gastric epithelial cells; and (b) this effect is specifically related to VacA toxin and seems to depend on the activation of an EGFR-, MAP kinase-, and COX-2-mediated pathway.  相似文献   
79.
Wolff-Parkinson-White syndrome is important for the anesthesiologist because the sudden development of tachyarrhythmias may result in deleterious hemodynamic changes. We describe an episode of reciprocating tachycardia triggered by the insertion of the guide wire during central venous cannulation in a patient with this syndrome.  相似文献   
80.
The authors describe a 3-day-old newborn admitted with signs of intestinal obstruction caused by solitary intestinal fibromatosis (SIF). This is a very rare lesion, which has an excellent prognosis. The differential diagnosis of bilious vomiting in a neonate caused by other than tumorous processes in the neonatal intestine is extensive. Probably this kind of lesion is more frequent in the neonatal period than thought until now but underdiagnosed because of the difficulty of diagnosis. Therapy of choice is wide local excision, and prognosis is excellent.  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