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   81535篇
  免费   5821篇
  国内免费   226篇
耳鼻咽喉   1035篇
儿科学   2125篇
妇产科学   1856篇
基础医学   12834篇
口腔科学   1917篇
临床医学   7843篇
内科学   16741篇
皮肤病学   1413篇
神经病学   7164篇
特种医学   3404篇
外国民族医学   45篇
外科学   11060篇
综合类   650篇
现状与发展   1篇
一般理论   87篇
预防医学   6317篇
眼科学   1751篇
药学   5913篇
中国医学   233篇
肿瘤学   5193篇
  2023年   361篇
  2022年   865篇
  2021年   1813篇
  2020年   1057篇
  2019年   1440篇
  2018年   1729篇
  2017年   1199篇
  2016年   1397篇
  2015年   1596篇
  2014年   2003篇
  2013年   3078篇
  2012年   4238篇
  2011年   4338篇
  2010年   2925篇
  2009年   2476篇
  2008年   3880篇
  2007年   4017篇
  2006年   3864篇
  2005年   3729篇
  2004年   3652篇
  2003年   3309篇
  2002年   3358篇
  2001年   2680篇
  2000年   2683篇
  1999年   2391篇
  1998年   1046篇
  1997年   876篇
  1996年   769篇
  1995年   770篇
  1994年   656篇
  1993年   702篇
  1992年   1616篇
  1991年   1511篇
  1990年   1466篇
  1989年   1440篇
  1988年   1204篇
  1987年   1188篇
  1986年   1124篇
  1985年   1027篇
  1984年   758篇
  1983年   695篇
  1982年   495篇
  1981年   473篇
  1980年   409篇
  1979年   652篇
  1978年   386篇
  1977年   374篇
  1975年   392篇
  1974年   424篇
  1973年   354篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
Failure of genetically selected miniature swine to model NIDDM   总被引:2,自引:0,他引:2  
Ten young adult miniature swine from a line reported to be genetically selected for glucose intolerance and eight normal controls were obtained from Colorado State University. They were consecutively exposed to 4 mo of a high-fiber, low-fat standard swine diet; 4 mo of a high-sucrose, high-fat, low-fiber diabetogenic diet; and 4 mo of excess diabetogenic diet for obesification. Results of oral glucose tolerance and intravenous insulin tolerance tests conducted at the end of each regimen were compared. Hyperglycemia was not observed in any animals after any manipulation. Insulin sensitivity was also not influenced by diet. We conclude that F7 low-K miniature swine from this colony fail to model human non-insulin-dependent diabetes.  相似文献   
24.
OBJECTIVE.--To determine behavioral and demographic risk factors for human immunodeficiency virus (HIV) infection in central Africa. DESIGN.--Cross-sectional survey. SETTING.--Kigali, Rwanda. PARTICIPANTS.--A representative sample of 1458 childbearing women aged 19 to 37 years who were recruited from outpatient prenatal and pediatric clinics at the only community hospital in the city. MAIN OUTCOME MEASURE.--Antibodies to HIV assessed by enzyme immunoassay and confirmed by Western blot or indirect immunofluorescence. RESULTS.--The HIV seroprevalence was 32% overall. Infection rates were higher in women who were single, in those in steady relationships that began after 1981, and in the 33% of women reporting more than one lifetime sexual partner. Women in legal marriages or monogamous partnerships had lower rates of infection, but even low-risk women had prevalences on the order of 20%. History of venereal disease in the past 5 years, although the strongest risk factor in a multiple logistic analysis (odds ratio, 2.7; 95% confidence interval, 2.0 to 3.7), was reported by only 30% of those infected. Having a male sexual partner who drank alcohol or who had higher income were significant risk factors for HIV infection in the multivariate analysis, but use of oral contraceptives and having an uncircumcised partner were not. CONCLUSIONS.--The epidemic of the acquired immunodeficiency syndrome in Rwanda has spread beyond high-risk groups to the general population of women without known risk factors. For most of these women, a steady male partner is the source of their HIV risk and therefore a vital target for intervention efforts.  相似文献   
25.
26.
A quantitative assay for ALZ-50 immunoreactivity was evaluated in samples of superior temporal gyrus taken at autopsy from 13 Alzheimer patients and 11 controls. The assayable immunoreactivity appears to be stable for at least 24 hours postmortem but was lost with formalin fixation. The mean value of the Alzheimer patients was tenfold higher than that of the controls (P less than .002). The values of four Alzheimer samples overlapped with the low levels seen in controls, but no controls had elevated levels. In this sample population, therefore, the assay had a sensitivity of 69% and specificity of 100%.  相似文献   
27.
The absolute activities of the pure beta-emitters 89Sr and 90Y have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number of radionuclides that have been standardized by this non-extrapolation liquid scintillation (LS) method. Both measurements were carried out within the framework of international key comparisons under the auspices of the International Bureau of Weights and Measures (BIPM). The TDCR results agreed well with those of other participating national laboratories, most using alternative (tracer) methods.  相似文献   
28.
International Journal of Clinical Pharmacy - In order to calculate the minimum sterilization process conditions to obtain the generally accepted sterility level (less than 1·10?6...  相似文献   
29.
30.
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