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   3047篇
  免费   102篇
耳鼻咽喉   9篇
儿科学   96篇
妇产科学   73篇
基础医学   189篇
口腔科学   65篇
临床医学   689篇
内科学   846篇
皮肤病学   100篇
神经病学   86篇
特种医学   3篇
外科学   335篇
综合类   33篇
一般理论   18篇
预防医学   194篇
眼科学   22篇
药学   328篇
肿瘤学   63篇
  2016年   37篇
  2015年   43篇
  2014年   42篇
  2013年   81篇
  2012年   23篇
  2011年   15篇
  2010年   86篇
  2009年   100篇
  2008年   29篇
  2007年   26篇
  2006年   39篇
  2005年   13篇
  2003年   20篇
  2002年   17篇
  2001年   53篇
  2000年   20篇
  1999年   101篇
  1998年   128篇
  1997年   181篇
  1996年   170篇
  1995年   134篇
  1994年   111篇
  1993年   109篇
  1992年   111篇
  1991年   90篇
  1990年   84篇
  1989年   84篇
  1988年   85篇
  1987年   67篇
  1986年   64篇
  1985年   47篇
  1984年   52篇
  1983年   47篇
  1982年   42篇
  1981年   55篇
  1980年   38篇
  1979年   36篇
  1978年   35篇
  1977年   31篇
  1976年   33篇
  1975年   23篇
  1972年   14篇
  1971年   19篇
  1959年   55篇
  1958年   69篇
  1957年   55篇
  1956年   57篇
  1955年   50篇
  1954年   60篇
  1948年   25篇
排序方式: 共有3149条查询结果,搜索用时 0 毫秒
41.
Nine human monoclonal antibodies (MoAbs) recognizing 7 different antigenic structures of blood-stages of the human malarial parasite P. falciparum (Pf) were produced by Epstein-Barr virus transformed B-cell lines (EBV-TCL) with or without fusion to the lymphoblastoid cell line KR4. The peripheral blood B-lymphocytes were obtained from 8 Gambian donors immune to Pf malaria. Two of the EBV-TCL could be expanded and maintained for more than 6 months but neither one could be cloned. Six additional EBV-TCL were stabilized after fusion with the KR4 lymphoblastoid cell line. All resulting hybridomas permitted easy cloning. Some of the MoAbs produced distinct fluorescent staining patterns of asexual Pf blood-stage parasites when using high-resolution digitized video-intensified fluorescence microscopy. Antigens on 195 kD and 155 kD proteins were recognized by 3 and 1 MoAb, respectively, using Western blotting and immunoprecipitation techniques.  相似文献   
42.
The distribution of both heavy drinking and drinking problems are well known from several previous studies. Not surprisingly, drinking problems are more prevalent among the demographic groups where heavy drinking is also more prevalent. This well-known conjunction, however, does little to determine whether some groups are more likely than others to experience drinking problems when we control for the amount of alcohol consumed. Here, this question is punned through a multiple regression analysis in which the dependent variable is a score on a drinking problem scale and the independent variables are: the frequency of heavy drinking occasions, sex, age, marital status, region, urbanicity, income, and education. The results indicate that none of these demographic variables had a strong association with the reported problem level.  相似文献   
43.
44.
45.
46.
The effects of propafenone on left ventricular function and hemodynamics are presented in this study. In one group of 13 patients who underwent electrophysiological testing and subsequent chronic oral therapy with propafenone, eight had left ventricular ejection fractions determined by nuclear study before and during therapy with the drug. Initial measurements ranged from 22% to 39% (mean 30%), while those on chronic therapy showed no statistical difference and ranged from 22% to 48% (mean 30%). In a separate dose titration study of 14 patients, left ventricular ejection fraction showed a modest but significant decrease (52%± 9% to 48%± 11%; p < 0.05). This change was more marked in patients with an initial low ejection fraction. Propafenone appears to be safe in these patients but should be administered with caution in patients with particularly low ejection fractions.  相似文献   
47.
48.
Summary. The objectives of this article were to study the reported prevalence of haemophilia B (HB) on a country‐by‐country basis and to analyse whether the prevalence of HB varied by national economy. The prevalence of HB is the proportion of diagnosed, reported cases of HB in a population at a specific point of time. We collected data on the HB prevalence for 105 countries from the World Federation of Hemophilia annual global surveys. Our results showed that the HB prevalence varied considerably among countries, even among the wealthiest of countries. The HB prevalence (per 100 000 males) for the highest income countries was 2.69 ± 1.61 (mean ± SD), whereas the prevalence for the rest of the world was 1.20 ± 1.33 (mean ± SD). Ireland had the highest reported HB prevalence of 8.07 per 100 000 males. There was a strong trend of increasing HB prevalence (per 100 000 males) over time. Prevalence data reported from the WFH compared well with prevalence data from the literature. The WFH annual global surveys have some limitations, but they are the best available source of worldwide haemophilia data. Prevalence data are extremely valuable information for the planning efforts of national healthcare agencies in setting priorities and allocating resources for the treatment of HB.  相似文献   
49.
50.
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