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   450篇
  免费   24篇
  国内免费   34篇
儿科学   22篇
妇产科学   4篇
基础医学   35篇
口腔科学   3篇
临床医学   60篇
内科学   109篇
皮肤病学   3篇
神经病学   35篇
特种医学   117篇
外科学   16篇
综合类   45篇
预防医学   17篇
眼科学   3篇
药学   26篇
肿瘤学   13篇
  2021年   2篇
  2020年   2篇
  2019年   2篇
  2018年   3篇
  2016年   2篇
  2015年   3篇
  2014年   4篇
  2013年   7篇
  2012年   7篇
  2011年   9篇
  2010年   9篇
  2009年   15篇
  2008年   9篇
  2007年   31篇
  2006年   3篇
  2005年   11篇
  2004年   12篇
  2003年   10篇
  2002年   15篇
  2001年   24篇
  2000年   20篇
  1999年   14篇
  1998年   29篇
  1997年   20篇
  1996年   14篇
  1995年   18篇
  1994年   26篇
  1993年   16篇
  1992年   8篇
  1991年   9篇
  1990年   11篇
  1989年   16篇
  1988年   13篇
  1987年   13篇
  1986年   11篇
  1985年   23篇
  1984年   12篇
  1983年   2篇
  1982年   8篇
  1981年   8篇
  1980年   9篇
  1979年   5篇
  1978年   3篇
  1977年   3篇
  1976年   4篇
  1970年   2篇
  1969年   1篇
  1968年   1篇
  1927年   2篇
  1887年   2篇
排序方式: 共有508条查询结果,搜索用时 31 毫秒
501.
502.
This is the sixth hypertension guideline published by the Southern African Hypertension Society (SAHS). Currently 30.4% of the adult population have hypertension (HTN),1 necessitating a simplified approach to assessment and treatment, which reflects realistic objectives that can be implemented by medical practitioners, nurse practitioners and pharmacists to diminish the impact of HTN and related cardiovascular disease (CVD) risk in this country. For full details on management not contained in this document please refer to the more detailed hypertension guideline 2011.2  相似文献   
503.
The effect of the lipid A moiety of endotoxin on platelet and fibrinogen production was studied in rabbits. Lipid A was infused intravenously in doses ranging from 1 to 100 micrograms/kg body mass; 18 hr later, selenomethionine-75Se was injected intravenously and its incorporation into fibrinogen and platelets determined. Lipid A in saline stimulated fibrinogen and platelet production, but the dose required was 50--100 times that required for an intact endotoxin. Although lipid A solubilized in triethylamine (TEA) was at least 60 times more active in the Limulus amebocyte lysate assay than was lipid A suspended in saline, the sensitivity of platelet and fibrinogen production to solubilized lipid A was increased only twofold. Incorporation of lipid A into liposomes had no effect on its Limulus activity. Lipid A in liposomes continued to stimulate platelet, but not fibrinogen, production. Leukopenia that was induced by lipid A in TEA did not occur when rabbits received the same dose of lipid A in liposomes. Lipid A, like intact endotoxin, can stimulate platelet and fibrinogen production and induce leukopenia but the doses required are high. The low solubility of lipid A in aqueous solutions may be only one factor that determines its biologic activity.  相似文献   
504.
Blanchard  D; Bloy  C; Hermand  P; Cartron  JP; Saboori  AM; Smith  BL; Agre  P 《Blood》1988,72(4):1424-1427
The 32,000 molecular weight (mol wt) erythrocyte Rh D, c, and E polypeptides were separately purified from cDE/cDE erythrocytes by monoclonal immunoprecipitations and compared by two-dimensional iodopeptide mapping. Digestions of the isolated Rh polypeptides with alpha-chymotrypsin revealed a high degree of structural homology between c and E (13/14 iodopeptides were identical) and less striking homology between D and c or E (8/19 identical). The iodopeptide maps of Rh proteins purified by a nonimmunologic protocol from cDE/cDE erythrocytes were virtually identical to the composite pattern (D + c + E) deduced from the individual maps of Rh D, c, and E iodopeptides. Digestions of the isolated Rh polypeptides with trypsin revealed an overall homology of approximately 50% between iodopeptides derived from D, c, and E. These data indicate that the erythrocyte Rh D, c, and E antigens are carried by homologous but distinct molecular species; c and E appear more closely related to each other than to D.  相似文献   
505.
There have been conflicting reports in the literature about the protective effect of hemophilia on the occurrence of ischemic heart disease (IHD). Circulatory disease has been reported as the second most common cause of death in persons with hemophilia in the United States. In addition to diabetes and hypertension, high levels of FVIII, as may occur during factor concentrate infusions, may increase IHD risk in this population. To estimate the prevalence of heart disease and examine factors associated with IHD and other heart diseases among persons with hemophilia, we analyzed data collected from the medical records of 3,422 males with hemophilia living in six U.S. states from 1993 to 1998. Heart disease cases were ascertained from among 2,075 persons who were hospitalized at least once during the 6-year period. Of these, 48 were diagnosed with IHD and 106, with other types of heart disease. The age-specific prevalence of IHD ranged from 0.05% in those under 30 years to 15.2% in those 60 years or older. Hospital discharge rates in males with hemophilia with IHD and other types of heart disease were lower compared to rates in age-matched U.S. males. In our cohort, as in the general population, IHD was independently associated with age, hypertension, diabetes, and hyperlipidemia. Other heart diseases were associated with HIV infection, hypertension, hemophilia B, and diabetes. In summary, persons with hemophilia have unique risk factors such as infusion of factor concentrates and infection with HIV that may predispose them to heart disease as their life expectancy increases.  相似文献   
506.
The human T-cell lymphotropic virus type I (HTLV-I) is causally associated with adult T-cell leukemia, but its role in mycosis fungoides (MF) has remained enigmatic. The virus is suspect because a small percentage of patients with MF have antibodies to it, the cells of others harbor deleted HTLV-I proviral sequences, and particles resembling HTLV-I emerge in cultured blood lymphocytes obtained from most patients. An alternative possibility is that disparate lymphotropic retroviruses may infect or affect a population of epidermotropic lymphocytes, leading to the same outcome, ie, MF. In studies designed to identify the particles detected in lymphocyte cultures of nine patients with a diagnosis of skin involvement characteristic of MF, this concept has gained support. While the cells of four patients provided evidence of HTLV-I infection, molecular hybridization with HTLV-II-specific pol probes showed HTLV-II in the cells of another patient. The 103-bp fragment amplified by the HTLV-II-specific probe was sequenced and proved to have greater than 90% homology with the same fragment amplified from cells known to be infected with HTLV-II. A role for HTLV-II in MF has not been suggested heretofore. Therefore, HTLV-I, HTLV-II, and their incomplete forms may be found in cells of MF patients, suggesting new theories regarding the pathogenesis of this disease.  相似文献   
507.
508.
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