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   300100篇
  免费   17793篇
  国内免费   422篇
耳鼻咽喉   4272篇
儿科学   10369篇
妇产科学   10269篇
基础医学   45632篇
口腔科学   7587篇
临床医学   24455篇
内科学   56814篇
皮肤病学   6357篇
神经病学   21238篇
特种医学   11914篇
外国民族医学   43篇
外科学   47425篇
综合类   7781篇
现状与发展   1篇
一般理论   161篇
预防医学   20113篇
眼科学   7003篇
药学   21079篇
中国医学   792篇
肿瘤学   15010篇
  2019年   2290篇
  2018年   3683篇
  2017年   2714篇
  2016年   3156篇
  2015年   3566篇
  2014年   4686篇
  2013年   7326篇
  2012年   9252篇
  2011年   9689篇
  2010年   6262篇
  2009年   5655篇
  2008年   8831篇
  2007年   9715篇
  2006年   9571篇
  2005年   9160篇
  2004年   8872篇
  2003年   8325篇
  2002年   7960篇
  2001年   13475篇
  2000年   13821篇
  1999年   11584篇
  1998年   3057篇
  1997年   2829篇
  1996年   2658篇
  1995年   2574篇
  1994年   2373篇
  1992年   8414篇
  1991年   8540篇
  1990年   8355篇
  1989年   8156篇
  1988年   7393篇
  1987年   7147篇
  1986年   6782篇
  1985年   6577篇
  1984年   4818篇
  1983年   4156篇
  1982年   2487篇
  1979年   4463篇
  1978年   3245篇
  1977年   2759篇
  1976年   2515篇
  1975年   2855篇
  1974年   3367篇
  1973年   3373篇
  1972年   3136篇
  1971年   2959篇
  1970年   2852篇
  1969年   2597篇
  1968年   2550篇
  1967年   2381篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
141.
Summary Intracavitary application of ultrasound was first performed for diagnostic purposes in 1967; since that time, it has been more and more widely used. As far as the gastrointestinal tract is concerned, endoscopically controlled ultrasonic probes provide visualization of the various layers of the intestinal wall. It is therefore possible to describe lesions of the esophagus, stomach, and the rectum with regard to their nature and depth of infiltration. Furthermore, periesophageal and perigastric organs can be visualized. It has become evident that endosonography is particularly important for pretherapeutic staging of tumors of the esophagus, stomach, and rectum. Here prospective comparative studies confirm the superiority of this new diagnostic procedure when compared to the methods available to date.  相似文献   
142.
143.
The acting or interim leadership position has been neglected in terms of selection, role identification, and status. Individuals, programs, and organizations are paying a price for this inattention.  相似文献   
144.
145.
Recently, we demonstrated that spaghetti caused significantly lower glycaemic response than rice and potato in insulin-dependent diabetic (IDDM) subjects and that this difference was also present when spaghetti and potato were taken as part of a mixed meal. We have now compared the blood glucose and insulin responses to 50 g of carbohydrate in the form of white bread, potato and white spaghetti in 6 non-insulin-dependent diabetic (NIDDM) patients. The blood glucose response after white spaghetti observed over a 3-h period was only 60 +/- 10 per cent (P less than 0.02) of that seen in response to potato (395 +/- 116 mmol/l x 180 min vs 641 +/- 108 mmol/l x 180 min) and 47 +/- 9 per cent (P less than 0.01) of that seen in response to white bread (395 +/- 116 mmol/l x 180 min vs 805 +/- 93 mmol/l x 180 min). Insulin responses showed an identical pattern reflecting the glycaemic responses. To see if the difference in the glucose responses in NIDDM patients is preserved if these carbohydrate-rich foods are taken as part of a mixed meal we looked at the blood glucose and insulin responses to 50 g of carbohydrate in the form of potato and white spaghetti when ingested together with bolognese sauce (167 g) in 7 NIDDM patients.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
146.
The in vitro activities of povidone iodine, potassium peroxymonosulfate, and dimethyldidecylammonium chloride were investigated against 379 nosocomial isolates of Staphylococcus aureus and Pseudomonas aeruginosa responsible for surgical wound infections in patients operated on between July 1995 and June 2001. Overall, the isolates were inhibited by the antiseptics at concentrations below those used routinely. In spite of increasing resistance to the various antibiotics used to treat surgical wound infections, no significant variation in the susceptibility to antiseptics was demonstrated during this 6-year study. Electronic Publication  相似文献   
147.
OBJECTIVE AND DESIGN: Bacterial products as well as the host airway inflammatory responses contribute to the pathogenesis of Pseudomonas infections. We sought to determine if Pseudomonas elastase (PE) induces mitogen-activated protein (MAP) kinase activity in association with interleukin-8 (IL-8) production by alveolar epithelial cells. METHODS: We utilized Western blot analysis to detect phosphorylation of signaling intermediates and ELISA was used to measure IL-8 production. RESULTS: We found that PE induces phosphorylation of the extracellular signal-regulated (ERK1/2) proteins of the MAPK pathway in A549 epithelial cells. Similar results were obtained using primary cultures of rabbit alveolar type II epithelial cells. PE also enhanced IL-8 production, which was abolished in the presence of the ERK activation inhibitor U0126. CONCLUSIONS: We conclude that PE activates the ERK1/2 arm of the MAPK pathway and that activation of this pathway results in enhanced IL-8 production. The results demonstrate that PE may augment pulmonary inflammation via cellular signaling that regulates expression of IL-8.  相似文献   
148.
149.
150.
Enhanced and non-enhanced computed tomography (CT) brain scans were performed within 72 h of surgery on 21 children in whom brain tumors had been resected totally or subtotally, and scans were repeated at varying intervals thereafter. Biopsies of the resection margins were performed in 12 patients at the end of the surgical procedure. The immediate CT scan showed enhancement in the resection margin in 13 of the 21 patients and in 9 of the 13, the enhancement disappeared on follow-up scans. There was discordance between the results of immediate CT scan examination and the biopsies of the resection margins in 7 of the 12 cases. The advantages and disadvantages of an immediate postoperative scan versus a more delayed CT scan are discussed.  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