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   372792篇
  免费   19312篇
  国内免费   1000篇
耳鼻咽喉   4839篇
儿科学   11610篇
妇产科学   8732篇
基础医学   52761篇
口腔科学   13423篇
临床医学   25458篇
内科学   82564篇
皮肤病学   10596篇
神经病学   31009篇
特种医学   10908篇
外国民族医学   56篇
外科学   45375篇
综合类   2442篇
现状与发展   1篇
一般理论   94篇
预防医学   39663篇
眼科学   8111篇
药学   25805篇
  2篇
中国医学   1412篇
肿瘤学   18243篇
  2023年   1755篇
  2022年   2832篇
  2021年   7302篇
  2020年   4442篇
  2019年   7171篇
  2018年   10274篇
  2017年   7067篇
  2016年   6988篇
  2015年   7867篇
  2014年   10373篇
  2013年   14235篇
  2012年   22245篇
  2011年   23133篇
  2010年   12112篇
  2009年   10515篇
  2008年   18656篇
  2007年   19846篇
  2006年   18907篇
  2005年   19033篇
  2004年   17819篇
  2003年   16431篇
  2002年   14304篇
  2001年   11304篇
  2000年   11708篇
  1999年   9792篇
  1998年   3036篇
  1997年   2427篇
  1996年   2315篇
  1995年   1974篇
  1994年   1854篇
  1993年   1685篇
  1992年   5622篇
  1991年   5314篇
  1990年   5050篇
  1989年   4705篇
  1988年   4325篇
  1987年   4022篇
  1986年   3915篇
  1985年   3689篇
  1984年   2689篇
  1983年   2259篇
  1979年   2469篇
  1975年   1684篇
  1974年   1940篇
  1973年   1987篇
  1972年   1800篇
  1971年   1715篇
  1970年   1699篇
  1969年   1761篇
  1968年   1736篇
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
941.
942.
943.
Noninvasive NMR methodology has been developed to enable monitoring of 13C-labeled xenobiotics in the rat in vivo. 2,2-Dichloro-1-(2-chlorophenyl)-1-(4-chlorophenyl)-[3-13C]-propane can be detected in the liver of intact rats by in vivo 13C surface coil NMR spectroscopy after ip administration of the compound. The experiments were performed at 1.9 and 9.4 Tesla. The intrahepatic changes of the signal intensity of the labeled compound were followed as a function of time. In the days following administration, the concentration decreased and dropped to values below the detection limit after 12 days. The study demonstrates the feasibility of studies on pharmacokinetics of 13C-labeled compounds in the rat using noninvasive, in vivo surface coil NMR spectroscopy in animals. The sensitivity allows the detection of a single dose of the drug of 200 mg/kg, but can be improved.  相似文献   
944.
945.
We report a case of a primary gastric Burkitt's lymphoma in a 8-year-old child, which first symptoms were abdominal pain, dysphagia, melena and a constitutional syndrome. The differential characteristics of this case are its peculiar gastric infiltration and the existence of oesophageal extension, which is very infrequent among this kind of tumors.  相似文献   
946.
Thirty patients with malignant tumours in the upper abdomen underwent surgery and intraoperalive radiation (IORT), using electron beam, to: the surgical bed, residual or unresected tumour. The technical aspects and results of this treatment are described. Renal, adrenal, bile duct and gastrointestinal tumours were treated. along with several other lesions. The surgical procedure consisted in 10 cases simply of exposure of the tumour for IORT and in 20 the tumour was resected. The TORT dose ranged from 10 to: 20 Gv. In 13 patients, external beam radiation was also given to: residual tumour or to: areas of high risk for recurrence. Chemotherapy was given to: 10 patients. Tolerance to: the combined treatment was acceptable; with few complications related to: IORT.The median follow-up and survival time 23 months (range 4-more than 70 months). Local tumour control rate (or tumour stabilisation) is 90%. Distant metastases developed in 19 patients (63%). The actuarial survival rate for the group projected at 70 months (maximum follow-up) is 37%. IORT in useful in the management of tumours arising in the upper abdominal organs, for palliation surgery or when resectability of the tumour is in doubt. Indications for IORT include patients with uncommon tumours of the upper abdomen who are not be candidates for standardised cancer treatment.Presented at the European Congress of Radiology, Vienna, September 15–20,1991  相似文献   
947.
The study of the venous channels in the cavernous sinus in 48 sphenoid bones was performed. Thirty-eight bones were electrolyticly decalcified, subsequently embedded in gelatin, and cut in 1 mm thick slices. Microdissection of the other ten specimens complemented the analysis. Every specimen had the venous structure arranged as a plexus, however, although the channels were variable in number, form, and diameter, the two sides were quite symmetrical. Channels of smaller diameter predominated anteriorly. There was no demonstrable muscular layer in these vessels; the endothelial lining was easily visualized. Fatty tissue separated the venous channels from each other and from arteries and nerves. The distance from the carotid artery and the lateral wall increased anteriorly, but there were significant veins between these two structures in only 35% of the cases. In about one third of specimens the oculomotor nerve was placed over the carotid artery. The abducens nerve was found to be intimately related to the lateral wall without any venous channels between them in 92% of the specimens.  相似文献   
948.
949.
Authors present a method of esophageal dilatation and report their experiences. The place of esophageal dilatation among other therapeutic approaches of esophageal stricture is discussed. The advantage of Savary-Gilliard bougies and guide wire and its applications are presented. During one and a half year 218 esophageal dilatations were performed at 82 patients. 11 patients were intubated endoscopically. Esophageal perforation occurred in 2 cases (0.93%). Dilatation of the esophagus with Savary-Gilliard bougies and using of the guide wire are considered a safe and many-sided method in the diagnosis and treatment of esophageal strictures.  相似文献   
950.
Detectable TNF levels in sera 33% of patients with sepsis following pancreatitis have been found. No correlation was observed between serum TNF concentration and the severity of illness. However, monocytes and granulocytes of septic patients exerted higher TNF-mediated cytotoxicity than leukocytes of normal blood donors. The in vitro TNF-producing capacity was also higher in the patients in the study group, and it decreased only before fatal outcoming of sepsis. Our results suggest that determination of the TNF-producing capacity of leukocytes might be more informative than measurement of the serum TNF level in the evaluation of the severity or prognosis of sepsis.  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