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   8375篇
  免费   623篇
  国内免费   29篇
耳鼻咽喉   31篇
儿科学   260篇
妇产科学   297篇
基础医学   1033篇
口腔科学   104篇
临床医学   1489篇
内科学   1248篇
皮肤病学   174篇
神经病学   870篇
特种医学   216篇
外科学   899篇
综合类   159篇
一般理论   39篇
预防医学   964篇
眼科学   173篇
药学   507篇
中国医学   4篇
肿瘤学   560篇
  2023年   45篇
  2022年   91篇
  2021年   178篇
  2020年   100篇
  2019年   186篇
  2018年   209篇
  2017年   157篇
  2016年   155篇
  2015年   202篇
  2014年   288篇
  2013年   384篇
  2012年   517篇
  2011年   566篇
  2010年   326篇
  2009年   289篇
  2008年   423篇
  2007年   520篇
  2006年   486篇
  2005年   490篇
  2004年   461篇
  2003年   419篇
  2002年   418篇
  2001年   130篇
  2000年   107篇
  1999年   124篇
  1998年   135篇
  1997年   115篇
  1996年   84篇
  1995年   76篇
  1994年   64篇
  1993年   59篇
  1992年   84篇
  1991年   92篇
  1990年   81篇
  1989年   73篇
  1988年   62篇
  1987年   65篇
  1986年   75篇
  1985年   77篇
  1984年   64篇
  1983年   58篇
  1982年   47篇
  1981年   43篇
  1980年   43篇
  1979年   42篇
  1978年   36篇
  1977年   28篇
  1976年   24篇
  1975年   27篇
  1974年   22篇
排序方式: 共有9027条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
76.
77.
Purpose : To collect qualitative information about personal experiences with stroke rehabilitation from members of a community based stroke club. Method : In this focused ethnographic study, four data collectors observed and videotaped two sessions of a community based stroke club. The videotape and written notes were reviewed and analysed according to standard qualitative research procedures. Results : Two themes emerged from analysis of the qualitative data: concerns that individualized needs were not addressed during the rehabilitation process and that services were insufficient to ease the transition to community living. Conclusions : Rehabilitation professionals can benefit from soliciting reflections and suggestions from individuals who have returned to community living after completing poststroke rehabilitation programmes. Specific recommendations are provided for tailoring interventions to meet individual goals, for enhancing follow up services provided after inpatient rehabilitation, and for providing early access to available resources in stroke survivors' communities.  相似文献   
78.
Lu  L; Broxmeyer  HE; Moore  MA; Sheridan  AP; Gentile  P 《Blood》1985,65(1):91-99
The regulation of myelopoiesis was evaluated in B6D2F1 mice inoculated with Friend virus complex (spleen focus-forming virus plus helper virus) or helper virus alone by analyzing acidic isoferritin (AIF) and lactoferrin (LF) interactions with target cells. Under normal conditions, AIF suppresses colony and cluster formation by an Ia- antigen-positive cycling subpopulation of mouse granulocyte-macrophage progenitor cells (CFU-GM). Under the same conditions, the release of AIF-inhibitory activity and granulocyte-macrophage colony stimulatory factors (GM-CSF) from an Ia-antigen-positive subpopulation of monocytes and macrophages is suppressed by LF. Within one to two days after inoculation in vivo with Friend virus complex or helper virus, mouse CFU-GM become insensitive in vitro to suppression by purified human AIF as well as crude mouse AIF, and by four days, bone marrow, spleen, and thymus cells of these mice release much greater quantities of AIF- inhibitory activity than the cells from mice injected with control medium. The Friend virus complex itself has no influence in vitro on CFU-GM from normal mice. In addition, the release of AIF-inhibitory activity from bone marrow, spleen, and resident peritoneal cells and the release of GM-CSF from resident peritoneal cells of mice infected with Friend virus complex are not suppressed by LF. The inability of AIF to suppress colony formation by bone marrow and spleen CFU-GM from mice infected with Friend virus complex is associated with the loss of Ia (I-A subregion) antigens from CFU-GM, even though CFU-GM are in cycle. The nonresponsiveness of bone marrow, spleen, and peritoneal cells from these mice to LF suppression of AIF release and the inability of LF to influence GM-CSF release from peritoneal cells is associated with loss of Ia antigens from these cells. The above abnormalities are similar to the defects noted using cells from patients with leukemia. These results suggest that mice infected with Friend virus complex can serve as a model for investigating abnormalities in cell regulation and their relationships to disease progression.  相似文献   
79.
Kaplan  AP; Gruber  B; Harpel  PC 《Blood》1985,66(3):636-641
An enzyme-linked immunosorbent assay has been developed for the quantitation of activated Hageman factor-C1 inactivator (HF-C1 INH) complexes. Addition of increasing quantities of either of the major forms of activated Hageman factor (HFa or HFf) to normal plasma or to Hageman factor-deficient plasma leads to a dose-dependent increase in activated HF-C1 INH complexes. As little as 0.5 micrograms/mL of activated HF added to plasma can be detected, corresponding to activation of approximately 2% of plasma HF. The sensitivity of the assay is increased at least tenfold when complexes are formed in HF- deficient plasma, indicating competition between unactivated HF and activated HF-C1 INH complexes for binding to the antibody. Specificity is demonstrated in that addition of activated HF to hereditary angioedema plasma yields less than 1% of the activated HF-C1 INH complex formation obtained with normal plasma. Kaolin activation of HF- deficient plasma yields no detectable complex formation. Kaolin activation of prekallikrein-deficient plasma demonstrates a time- dependent increase in formation of activated HF-C1 INH complex consistent with the ability of HF in this plasma to autoactivate as the time of incubation with the surface is increased. Kaolin treatment of high-molecular weight (HMW) kininogen-deficient plasma yields an even more profound abnormality in the rate of formation of activated HF-C1 INH complexes reflecting the complex role of HMW kininogen in the initiation of contact activation. Although addition of corn inhibitor to plasma prevents activated HF-C1 INH complex formation, it does not inhibit activated HF sufficiently fast to prevent prekallikrein activation.  相似文献   
80.
Chronic rejection accounts for most renal allograft losses after the first year posttransplantation. On March 24 and 25, 1997, a roundtable of five transplant surgeons, two nephrologists, and one pathologist assembled in Dallas, Texas, to review critical issues surrounding chronic renal allograft rejection. This article summarizes the presentations and relevant discussions of this meeting regarding the cause of chronic rejection, clinical diagnoses, risk factors, future prospects for intervention strategies, and general recommendations for the transplant community. Growing evidence indicates that chronic rejection is the aggregate sum of irreversible immunologic and nonimmunologic injuries to the renal graft over time. A history of acute rejection episodes and inadequate immunosuppression, likely attributable to inconsistent cyclosporine exposure or poor patient compliance, are among the most recognizable immunologic risk factors for chronic rejection. Donor organ quality, delayed graft function, and other donor and recipient variables leading to reduced nephron mass are nonimmunologic factors that contribute to the progressive deterioration of renal graft function. Clinical management of renal transplant recipients should incorporate both immunologic- and nonimmunologic-based intervention strategies aimed at minimizing risk factors to thwart the progression of chronic rejection and improve long-term allograft and patient survival.  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