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   3287篇
  免费   193篇
  国内免费   24篇
耳鼻咽喉   27篇
儿科学   47篇
妇产科学   76篇
基础医学   574篇
口腔科学   34篇
临床医学   287篇
内科学   861篇
皮肤病学   42篇
神经病学   253篇
特种医学   130篇
外科学   313篇
综合类   10篇
预防医学   90篇
眼科学   39篇
药学   417篇
中国医学   19篇
肿瘤学   285篇
  2023年   11篇
  2022年   30篇
  2021年   48篇
  2020年   30篇
  2019年   31篇
  2018年   40篇
  2017年   36篇
  2016年   60篇
  2015年   62篇
  2014年   93篇
  2013年   109篇
  2012年   225篇
  2011年   228篇
  2010年   129篇
  2009年   116篇
  2008年   232篇
  2007年   228篇
  2006年   271篇
  2005年   251篇
  2004年   217篇
  2003年   210篇
  2002年   230篇
  2001年   33篇
  2000年   28篇
  1999年   41篇
  1998年   58篇
  1997年   37篇
  1996年   32篇
  1995年   33篇
  1994年   22篇
  1993年   34篇
  1992年   17篇
  1991年   14篇
  1990年   21篇
  1989年   14篇
  1988年   15篇
  1987年   14篇
  1986年   11篇
  1985年   12篇
  1983年   21篇
  1982年   23篇
  1981年   8篇
  1980年   12篇
  1979年   9篇
  1978年   9篇
  1977年   8篇
  1976年   10篇
  1975年   15篇
  1973年   8篇
  1970年   8篇
排序方式: 共有3504条查询结果,搜索用时 15 毫秒
41.
Juvenile idiopathic arthritis (JIA) is the most common diagnosis in children and adolescents with rheumatic disorders. In many children and adolescents, JIA is successfully treated with non-steroidal anti-inflammatory drugs (NSAID) and physiotherapy. However, in a significant number of cases the disease is resistant to this therapy, and treatment with second line disease-modifying antirheumatic drugs (DMARDs) is required. Methotrexate (MTX) is frequently referred to as first-choice second-line agent for the treatment of JIA. To increase drug safety, the Working Groups for Children and Adolescents with Rheumatic Diseases in Germany (AGKJR) and Pediatric Rheumatology Austria have initiated the formulation of evidence-based recommendations. Evidence is based on consensus expert meetings, a MEDLINE search with the key words Methotrexate and juvenile arthritis limited to age 0–18 years, standard textbooks and review articles, data from the central registry of the German Research Center for Rheumatic Diseases (Deutsches Rheumaforschungszentrum Berlin DRFZ), experience with MTX in adults with rheumatoid arthritis (RA), and recommendations of the German Society of Rheumatology (DGRh). Based on these data, evidence and recommendations are graded, and evidence-based recommendations for the use of MTX in children and adolescents with rheumatic disease are presented.Section Pharmacotherapy of the Working Group Pediatric Rheumatology Germany and Austria: I. Foeldvari; J.P. Haas, A. Haeffner, D. Hobusch,G. Horneff, A. Hospach, R. Keitzer, G. Klaus, M. Metzler, H. Michels, T. Niehues, I. Pilz, M. Sailer Höck, M. Schöntube, L. Schuchmann, K. Schumacher, H.W. Seyberth, E. Siemers, A. Urban, E. Weißbarth-Riedl. Working Group Pediatric Rheumatology North-Rhine-Westfalia: S. Benseler, G. Bürk, S. Fahl, I. Foeldvari, D. Föll, M. Frosch, G. Ganser, S. Kastner, I. Kleine, E. Lainka, K. Mönkemöller, J. Neubert, U. Neudorf, T. Niehues, J. Roth, S. Seeliger, N. Wagner, R. Wieland, H. Winowski.  相似文献   
42.
43.
A new optical system for the measurement of the erythrocyte velocity in microvessels is extensively applied for the first time. It is based on the projection of the erythrocyte image onto two photodiodes through a prism grating. The differential signal of the photodiodes is proportional to the velocity. The system is comparable to those of M. Anliker, M. Casty, P. Friedli, R. Kubli, and H. Keller ((1977). Noninvasive measurement of blood flow. In “Cardiovascular Flow Dynamics and Measurement” (N. H. Hwang and N. Normann, eds.), pp. 43–88. Univ. Park Press, Baltimore) and D. W. Slaaf, J. P. S. M. Rood, G. J. Tangelder, and T. Arts ((1979). Microvasc. Res.17, S173). It measures an instantaneous velocity. The system is calibrated by a velocity which is constant over the total measuring field and by a known flow rate and profile. Concerning applicability and results the device is compared to the two-slit methods, the laser-Doppler-anemometry and high-speed cinematography.  相似文献   
44.
45.
46.
The loss of Gimap5 (GTPase of the immune-associated protein 5) gene function is the underlying cause of lymphopenia and autoimmune diabetes in the BioBreeding (BB) rat. The in vivo function of murine gimap5 is largely unknown. We show that selective gene ablation of the mouse gimap5 gene impairs the final intrathymic maturation of CD8 and CD4 T cells and compromises the survival of postthymic CD4 and CD8 cells, replicating findings in the BB rat model. In addition, gimap5 deficiency imposes a block of natural killer (NK)- and NKT-cell differentiation. Development of NK/NKT cells is restored on transfer of gimap5(-/-) bone marrow into a wild-type environment. Mice lacking gimap5 have a median survival of 15 weeks, exhibit chronic hepatic hematopoiesis, and in later stages show pronounced hepatocyte apoptosis, leading to liver failure. This pathology persists in a Rag2-deficient background in the absence of mature B, T, or NK cells and cannot be adoptively transferred by transplanting gimap5(-/-) bone marrow into wild-type recipients. We conclude that mouse gimap5 is necessary for the survival of peripheral T cells, NK/NKT-cell development, and the maintenance of normal liver function. These functions involve cell-intrinsic as well as cell-extrinsic mechanisms.  相似文献   
47.

Objective

To study low blood hemoglobin concentrations as a predictor of radiographic damage progression in patients with rheumatoid arthritis (RA).

Methods

Post hoc analyses were performed in patients from the PREMIER trial with early RA undergoing 2 years of adalimumab (ADA), methotrexate (MTX), or ADA + MTX combination therapy. Low disease activity was defined as a score <3.2 on the 28‐joint Disease Activity Score using the C‐reactive protein level (DAS28‐CRP), and clinical response by the American College of Rheumatology criteria for 20% improvement at week 24. Baseline or mean hemoglobin concentrations over time, or anemia as defined using sex‐specific World Health Organization criteria, were analyzed in mixed‐effects models for longitudinal data in men and women as predictors of progressive joint damage, as measured by the modified total Sharp/van der Heijde score (ΔSHS). Data were adjusted for treatment and other patient characteristics, including the DAS28‐CRP.

Results

Baseline hemoglobin was inversely associated with ΔSHS in adjusted analyses (P < 0.05 for both sexes). Baseline anemia predicted greater ΔSHS in MTX‐treated patients over 104 weeks, and in ADA‐ and combination‐treated patients over 26 weeks. Lower hemoglobin concentrations over time, as well as time with anemia, were associated with greater damage progression (P < 0.001). The effect of low hemoglobin concentrations on joint damage progression remained significant, even in patients achieving low disease activity.

Conclusion

Low hemoglobin is a DAS28‐CRP‐independent predictor of radiographic joint damage progression in MTX‐treated patients with early RA. This effect decreases over time in ADA‐ and combination‐treated patients, and in clinical responders irrespective of treatment modality.
  相似文献   
48.
The mortality rate after acute myocardial infarction (AMI) has generally been modeled by a single exponential function. The present study was undertaken to determine, in 3 different populations, whether or not periods exist during the first year after AMI which have mortality distributions that differ from this pattern. The 3 patient populations included San Diego (346 patients, 71 deaths), Vancouver (704 patients, 146 deaths), and Copenhagen (1,140 patients, 262 deaths). Hospital admission was within 24 hours of the onset of symptoms, and patients dying within the first 24 hours after hospital admission or of noncardiac or unknown causes were not analyzed. The mortality between 2 and 21 days in the combined data base was 11.4% (range 10.9 to 11.7) and from 3 weeks to 1 year 10.5% (range 9.0 to 11.3). A high degree of similarity was noted among the shapes of the 3 survival curves. The hypothesis of an exponential mortality rate during the entire first year was rejected. Using a special statistic, changepoints at days 17,23, and 24 in the 3 populations (21 days for the combined data base) were identified and used thereafter to divide the year into 2 separate periods of mortality within which exponentiality for the mortality rate was not rejected. The point by which exactly 50% of deaths had occurred was day 19, with 75% of deaths occurring by day 100. These data further define the natural history after AMI and indicate optimal follow-up periods for short- and longer-term management strategies based on risk assessment or trials of risk reduction after AMI.  相似文献   
49.
50.
The use of immunoglobulin (Ig) preparations (intravenous, IVIg, subcutaneous, SCIg) for replacement and immunomodulation therapy worldwide has tripled in the past 20 years and represents an ever‐increasing cost factor for healthcare organizations. The limited access to the starting material of this essential medicinal product is currently the driving force for human plasma collection. Increasing awareness and improved diagnosis of human primary immunodeficiencies and a broadening of immunomodulatory indications are responsible for this development, and on a longer run might lead to plasma supply shortages. Consensus recommendations for the optimal use of Ig in clinical practice, including priority rankings for the most urgent indications, are therefore urgently needed. During a recent meeting in Kreuth, Germany, expert nominees from 36 Council of Europe states, together with colleagues from observer countries and regulatory agencies came up with this consensus statement.

  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