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   14753篇
  免费   668篇
  国内免费   44篇
耳鼻咽喉   206篇
儿科学   229篇
妇产科学   197篇
基础医学   2105篇
口腔科学   492篇
临床医学   915篇
内科学   3427篇
皮肤病学   182篇
神经病学   1201篇
特种医学   763篇
外科学   2298篇
综合类   85篇
一般理论   1篇
预防医学   513篇
眼科学   324篇
药学   1028篇
中国医学   29篇
肿瘤学   1470篇
  2023年   63篇
  2022年   129篇
  2021年   266篇
  2020年   142篇
  2019年   175篇
  2018年   222篇
  2017年   189篇
  2016年   225篇
  2015年   247篇
  2014年   296篇
  2013年   385篇
  2012年   663篇
  2011年   719篇
  2010年   399篇
  2009年   394篇
  2008年   634篇
  2007年   721篇
  2006年   715篇
  2005年   698篇
  2004年   756篇
  2003年   796篇
  2002年   740篇
  2001年   466篇
  2000年   516篇
  1999年   461篇
  1998年   225篇
  1997年   197篇
  1996年   150篇
  1995年   133篇
  1994年   137篇
  1993年   154篇
  1992年   362篇
  1991年   337篇
  1990年   292篇
  1989年   271篇
  1988年   252篇
  1987年   230篇
  1986年   201篇
  1985年   186篇
  1984年   158篇
  1983年   134篇
  1981年   57篇
  1980年   55篇
  1979年   83篇
  1978年   68篇
  1977年   77篇
  1975年   68篇
  1972年   59篇
  1968年   62篇
  1967年   67篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
1.
2.
Sessile serrated adenoma/polyps (SSA/Ps) are early precursor lesions in the serrated neoplasia pathway, which results in BRAF‐mutated colorectal carcinomas with not only high levels of microsatellite instability but also microsatellite stable. SSA/Ps with advanced histology, including cytological dysplasia or minimally invasive carcinomas, are important lesions because SSA/Ps are considered major contributors to “interval cancers” and these lesions can rapidly become dysplastic or invasive carcinomas. Clinicopathologically, SSA/Ps with dysplasia or invasive carcinoma were associated with advanced age, female sex, and proximal colon. Although SSA/Ps with submucosal invasive carcinoma were smaller and invaded less deeply into the submucosal layer than conventional tubular adenomas with submucosal invasive carcinoma, SSA/Ps with submucosal invasive carcinoma frequently had a mucinous component and exhibited a higher potential for lymphatic invasion and lymph node metastasis. In an SSA/P series, endoscopic characteristics, including (semi)pedunculated morphology, double elevation, central depression, and reddishness, may help accurately diagnose SSA/Ps with advanced histology. Removal of SSA/Ps with dysplasia or invasive carcinoma was recommended. Endoscopic treatment such as endoscopic mucosal resection or endoscopic submucosal dissection is useful for those lesions. However, surgical resection with lymph node dissection might be indicated when SSA/Ps with invasive carcinoma are endoscopically suspected, because these have the high risk of lymph node metastasis. Greater awareness may promote further research into improving the detection, recognition, and complete resection rates of SSA/Ps with dysplasia or invasive carcinoma and reduce the interval cancer rates.  相似文献   
3.
4.
5.
6.
7.
A 14-year-old boy had a needle accidentally inserted through his chest wall. Chest X-ray showed a needle-shaped metallic density localized in the cardiac silhouette. An echocardiography indicated the needle had passed through the interventricular septum, and its eye and point had reached the right and left ventricle, respectively. Surgical removal of the needle was performed. The needle could not be observed from the heart surface, and was recognized in a dent 5 mm on the right side from the left anterior descending branch (LAD). The needle was easily removed under extracorporeal circulation, and he was discharged ten days after the operation.  相似文献   
8.
9.
Osteoclastogenesis inhibitory factor (OCIF) is a novel secreted protein that inhibits osteoclastogenesis both in vitro and in vivo. In this study, we examined the effects of OCIF on serum calcium (Ca) concentrations in normal mice and in hypercalcemic nude mice carrying tumors associated with humoral hypercalcemia of malignancy. In normal mice, a single intraperitoneal injection of OCIF reduced serum Ca levels in a dose-dependent manner. Significant decrease in serum Ca (by 1.6 ± 0.3 mg/dL, n = 5) was observed 2 h after the injection of OCIF at 20 mg/kg and the hypocalcemic effect continued for up to 12 h. Serum phosphate (Pi) concentrations also decreased in response to OCIF. Urinary excretion of Ca, Pi, and creatinine did not change significantly after injection of OCIF or vehicle. In hypercalcemic, tumor-bearing nude mice, a single intraperitoneal injection of OCIF at 20 mg/kg resulted in a dramatic decrease in serum Ca (maximal decrease 2.8 ± 0.37 mg/dL, n = 11), which continued for up to 24 h. The results suggest that OCIF decreased serum Ca through its inhibitory effect on bone resorption. Furthermore, it is suggested that OCIF has therapeutic potential for the treatment of hypercalcemic conditions such as malignancy-associated hypercalcemia.  相似文献   
10.
The effects of FUT-187 (6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate, CAS 103926-82-5), a novel synthetic protease inhibitor, were examined in experimental rat and canine models of pancreatitis. 1. FUT-187 significantly increased the survival of rats with trypsin- and phospholipase A2-induced pancreatitis in a dose-dependent manner (10-100 mg/kg, p.o.). 2. FUT-187 decreased plasma enzymatic activity reflecting the degree of pancreatitis in rats with ethionine-induced pancreatitis, and showed a tendency to ameliorate histopathological changes in the pancreas (10-100 mg/kg p.o.). 3. FUT-187 (10 mg/kg) produced an obvious improvement of various biochemical parameters of pancreatitis and also reduced histopathological changes in the pancreas in animals with experimental pancreatitis produced by the closed duodenal loop method. In addition, FUT-187 significantly increased the survival of dogs when given by direct administration into the lumen of the closed duodenal loop. The therapeutic effects of FUT-187 in experimental pancreatitis were nearly equal in most instances to those of camostat mesilate. Thus, FUT-187 would appear to be an effective new agent for the treatment of pancreatitis.  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