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   706428篇
  免费   48792篇
  国内免费   1305篇
耳鼻咽喉   9168篇
儿科学   23276篇
妇产科学   17613篇
基础医学   110440篇
口腔科学   19974篇
临床医学   63773篇
内科学   134521篇
皮肤病学   16190篇
神经病学   49450篇
特种医学   25749篇
外国民族医学   76篇
外科学   104532篇
综合类   14826篇
现状与发展   2篇
一般理论   160篇
预防医学   51404篇
眼科学   16335篇
药学   53958篇
  3篇
中国医学   2360篇
肿瘤学   42715篇
  2021年   5445篇
  2018年   7869篇
  2017年   6110篇
  2016年   6828篇
  2015年   7556篇
  2014年   10271篇
  2013年   15391篇
  2012年   20502篇
  2011年   21495篇
  2010年   12729篇
  2009年   11940篇
  2008年   20002篇
  2007年   21524篇
  2006年   21908篇
  2005年   20450篇
  2004年   20002篇
  2003年   18952篇
  2002年   18465篇
  2001年   36340篇
  2000年   36915篇
  1999年   30397篇
  1998年   7884篇
  1997年   6679篇
  1996年   6984篇
  1995年   6640篇
  1994年   6107篇
  1993年   5602篇
  1992年   23002篇
  1991年   22941篇
  1990年   22321篇
  1989年   22085篇
  1988年   20047篇
  1987年   19430篇
  1986年   18483篇
  1985年   17315篇
  1984年   12702篇
  1983年   10743篇
  1982年   5928篇
  1979年   11528篇
  1978年   8129篇
  1977年   6836篇
  1976年   6596篇
  1975年   7270篇
  1974年   8500篇
  1973年   8143篇
  1972年   7661篇
  1971年   7132篇
  1970年   6882篇
  1969年   6309篇
  1968年   5780篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
Summary Five monoclonal antibodies against the excretory/secretory (E/S) antigen of Toxocara canis were obtained and characterized. Immunoprecipitating activity was demonstrated in an in-vitro micropre-cipitating assay using live T. canis larvae. Their capacity to kill larvae was also shown in an in-vitro assay. Two zones of reactivity were observed in 7.5 and 12.5% SDS-PAGE (177-77 kD, 43-15 kD) of immunoprecipitates of human and mouse positive polyclonal anlisera. The murine monoclonal antibodies showed a common pattern of reactivity with the proteins in the 177-77 kD range.  相似文献   
162.
163.
164.
Background.Computers that collect data from patients and provide both patients and practitioners with printed feedback on a range of health risks are a tool for assisting general practitioners with preventive care. This study assessed the impact of computer-generated printed feedback on cervical screening among women who were underscreened for cervical cancer.Method.Female attenders at two Australian general practices were randomly allocated to Experimental or Control groups. Women in both groups completed a health risk survey on a touch screen computer prior to their consultation. Those in the Experimental group received printed pages summarizing their results, including their eligibility for cervical screening and last Pap test, for themselves and their doctor. The number and proportion of underscreened women who had a Pap test in the 6 months after completing the computer survey, as determined by pathology records, were examined.Results.Of the 679 participants, 139 were classified as underscreened on the basis of self-report (74 Experimental, 65 Control) and 272 on the basis of their pathology records (148 Experimental, 124 Control). Overall about one-third of women had a test in the 6-month period, and the differences between the groups were not significant for women overall (18–70 years) or for women 18–49 years. Among women 50–70 who were underscreened based on self-report, those receiving the printout were more likely to have a Pap test in the next 6 months (P< 0.05). This pattern was also evident, but did not reach statistical significance, for older women who were underscreened based on pathology records.Conclusions.We are unable to draw conclusions regarding the effectiveness of the computer system due to the modest proportions of women screened, the small numbers, and the fact that the computer survey may have created an intervention effect in the Control group. As the study suggests the computer system is acceptable to women and may be effective for encouraging screening among older women, further exploration of the system is desirable.  相似文献   
165.
Some 50% of human cancers are associated with mutations in the core domain of the tumor suppressor p53. Many mutations are thought just to destabilize the protein. To assess this and the possibility of rescue, we have set up a system to analyze the stability of the core domain and its mutants. The use of differential scanning calorimetry or spectroscopy to measure its melting temperature leads to irreversible denaturation and aggregation and so is useful as only a qualitative guide to stability. There are excellent two-state denaturation curves on the addition of urea that may be analyzed quantitatively. One Zn2+ ion remains tightly bound in the holo-form of p53 throughout the denaturation curve. The stability of wild type is 6.0 kcal (1 kcal = 4.18 kJ)/mol at 25°C and 9.8 kcal/mol at 10°C. The oncogenic mutants R175H, C242S, R248Q, R249S, and R273H are destabilized by 3.0, 2.9, 1.9, 1.9, and 0.4 kcal/mol, respectively. Under certain denaturing conditions, the wild-type domain forms an aggregate that is relatively highly fluorescent at 340 nm on excitation at 280 nm. The destabilized mutants give this fluorescence under milder denaturation conditions.  相似文献   
166.
In this paper, the authors describe some of the complexities of collecting and presenting data on race and ethnicity based on the experiences of the Bureau of the Census. Different methods of data collection, different content and format of questions, and different definitions make it difficult to collect consistent race and ethnic data across data systems. The Bureau of the Census experiences have shown that changing ethnic self-identity and concepts, intent of the question, consistency of reporting, and the classification of persons of mixed racial parentage affect the quality of the data. These are some of the issues that must be addressed as statistical agencies and researchers seek to provide comparable race and ethnic data.  相似文献   
167.
168.
169.
170.
Acute renal failure (ARF) developed in a 7-week-old infant due to bilateral candidal bezoars (fungal balls) causing obstruction at the pelviureteric junction. The baby was born at term with an appropriate birthweight, and had been treated with broad-spectrum antibiotics for respiratory distress and septicemia during the 1st week of life. Recovery from ARF followed renal decompression with bilateral nephrostomy tube placement and parenteral administration of amphotericin B and 5-flucytosine. Received August 21, 1996; received in revised form and accepted January 3, 1997  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