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   3603篇
  免费   200篇
  国内免费   12篇
耳鼻咽喉   49篇
儿科学   149篇
妇产科学   51篇
基础医学   403篇
口腔科学   88篇
临床医学   230篇
内科学   629篇
皮肤病学   79篇
神经病学   240篇
特种医学   254篇
外国民族医学   1篇
外科学   405篇
综合类   119篇
预防医学   244篇
眼科学   241篇
药学   377篇
中国医学   12篇
肿瘤学   244篇
  2022年   41篇
  2021年   65篇
  2020年   31篇
  2019年   57篇
  2018年   63篇
  2017年   52篇
  2016年   69篇
  2015年   82篇
  2014年   86篇
  2013年   133篇
  2012年   214篇
  2011年   207篇
  2010年   122篇
  2009年   131篇
  2008年   140篇
  2007年   154篇
  2006年   140篇
  2005年   130篇
  2004年   145篇
  2003年   113篇
  2002年   95篇
  2001年   69篇
  2000年   78篇
  1999年   97篇
  1998年   85篇
  1997年   80篇
  1996年   77篇
  1995年   59篇
  1994年   54篇
  1993年   54篇
  1992年   73篇
  1991年   67篇
  1990年   71篇
  1989年   65篇
  1988年   49篇
  1987年   60篇
  1986年   57篇
  1985年   41篇
  1984年   35篇
  1983年   38篇
  1982年   30篇
  1981年   17篇
  1980年   26篇
  1979年   26篇
  1978年   23篇
  1976年   20篇
  1974年   17篇
  1973年   36篇
  1971年   16篇
  1970年   19篇
排序方式: 共有3815条查询结果,搜索用时 15 毫秒
1.
Studies were conducted to compare the toxicity of ethylene dichloride (EDC) in F344/N rats, Sprague-Dawley rats, and Osborne-Mendel rats. Ten rats/sex/group were exposed to EDC in drinking-water at 0, 500, 1000, 2000, 4000 and 8000 ppm for 13 wk. The highest concentration was limited by the maximum solubility of EDC in water (about 9000 ppm). In addition, F344/N rats (10/sex/group) were administered EDC in corn oil by gavage to compare toxicity resulting from bolus administration with that of continuous exposure in drinking-water. Gavage doses of EDC were within the range of total daily doses (in mg/kg body weight/day) resulting from exposure in drinking-water. EDC administered by gavage resulted in greater toxicity to F344/N rats than did administration of similar doses in drinking-water. All males receiving 240 and 480 mg/kg body weight and 9/10 females receiving 300 mg/kg body weight by gavage died before the end of the study. Necrosis of the cerebellum was observed in the brains of 3 males receiving 240 mg/kg body weight and 3 females receiving 300 mg/kg body weight. Hyperplasia and inflammation of the forestomach mucosa were observed in 8 male and 3 female rats that died or were killed in moribund condition. EDC caused minimal toxicity to F344/N, Sprague-Dawley and Osborne-Mendel rats at the drinking-water concentrations used in these studies; only female F344/N rats had EDC-related renal lesions. Based on mortality and EDC-related lesions, the no-effect levels for EDC administered by gavage to F344/N rats were 120 mg/kg body weight for males and 150 mg/kg body weight for females.  相似文献   
2.
3.
The aqueous extract of the fruits of Terminalia chebula Retz. has been evaluated for its antidiabetic activity in streptozotocin (STZ) induced mild diabetic rats and compared with a known drug, tolbutamide. The oral effective dose (ED) of the extract was observed to be 200 mg/kg body weight, which produced a fall of 55.6% (p<0.01) in the oral glucose tolerance test. Oral administration of ED of aqueous extract of T.chebula (AETC) daily once for two months reduced the elevated blood glucose by 43.2% (p<0.01) and significantly reduced the increase in glycosylated hemoglobin (HbA1c) (p<0.01). The same dose also showed a marked improvement in controlling the elevated blood lipids as well as decreased serum insulin levels in contrast to the untreated diabetic animals. Hepatic and skeletal muscle glycogen content decreased by 75% and 62.9% respectively in diabetic controls, these alterations were partly prevented (34.9% and 21.17%) in AETC treated group when compared to the healthy controls. The in vitro studies with pancreatic islets showed that the insulin release was nearly two times more than that in untreated diabetic animals. The treatment did not have any unfavorable effect on other blood parameters of liver and kidney function tests. LD 50 was found to be above 3 g/kg bw i.e. 15 times of ED, because there were no deaths of animals even at this dose indicating high margin of safety. These findings suggest further investigations for the possible use of the aqueous extract of fruits of T.chebula for the treatment of diabetes.  相似文献   
4.
5.
6.
7.
8.
Tuberculosis is still a major cause of spinal compression in the developing countries. In this study 200 patients presenting with neurological lesions secondary to tuberculosis of the spine have been classified according to the Frankel classification and the results evaluated. A combination of surgical decompression and chemotherapy is advocated. The dangers of non-operative treatment are discussed.  相似文献   
9.
10.
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