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   2268篇
  免费   134篇
  国内免费   9篇
耳鼻咽喉   5篇
儿科学   44篇
妇产科学   30篇
基础医学   458篇
口腔科学   44篇
临床医学   220篇
内科学   484篇
皮肤病学   39篇
神经病学   148篇
特种医学   133篇
外科学   320篇
综合类   7篇
预防医学   104篇
眼科学   54篇
药学   113篇
中国医学   5篇
肿瘤学   203篇
  2023年   8篇
  2022年   11篇
  2021年   24篇
  2020年   21篇
  2019年   22篇
  2018年   41篇
  2017年   46篇
  2016年   32篇
  2015年   36篇
  2014年   66篇
  2013年   71篇
  2012年   113篇
  2011年   134篇
  2010年   81篇
  2009年   81篇
  2008年   131篇
  2007年   143篇
  2006年   156篇
  2005年   158篇
  2004年   142篇
  2003年   152篇
  2002年   157篇
  2001年   39篇
  2000年   44篇
  1999年   43篇
  1998年   40篇
  1997年   23篇
  1996年   28篇
  1995年   11篇
  1994年   12篇
  1993年   21篇
  1992年   9篇
  1991年   16篇
  1990年   17篇
  1989年   14篇
  1988年   11篇
  1987年   8篇
  1986年   6篇
  1984年   7篇
  1982年   15篇
  1981年   6篇
  1980年   10篇
  1975年   6篇
  1974年   9篇
  1941年   7篇
  1939年   10篇
  1938年   7篇
  1932年   8篇
  1926年   5篇
  1924年   5篇
排序方式: 共有2411条查询结果,搜索用时 312 毫秒
31.
Her-2/neu is a tumor-associated antigen that is expressed on several adenocarcinomas and correlates with poor prognosis. In a previous study (H. J. Bühring et al., Blood, 86: 1916-1923, 1995), it has been demonstrated that Her-2/neu expression can be detected on blast cells from patients with hematological malignancies including acute lymphoblastic leukemia (ALL). Here, we show that Her-2/neu-specific CTLs induced in vitro using peptide-pulsed dendritic cells efficiently lyse primary ALL blasts constitutively expressing both Her-2/neu and human leukocyte antigen A2 in an antigen-specific and MHC-restricted manner. Furthermore, we analyzed the feasibility of this approach in an autologous setting and induced Her-2/neu-specific CTLs using dendritic cells generated from peripheral blood mononuclear cells from an ALL patient that were pulsed with peptides or transfected with in vitro-transcribed Her-2/neu mRNA. Our data demonstrate that Her-2/neu could be used as a potential target for the application of Her-2/neu-directed treatment strategies in ALL including vaccination approaches.  相似文献   
32.
33.
PURPOSE: To prospectively assess potential risk factors for relapse in clinical stage I nonseminomatous germ cell tumors of the testis (CS I NSGCT). PATIENTS AND METHODS: From September 1996 to May 2002, 200 patients with CS I NSGCT were prospectively assigned to retroperitoneal lymph node dissection (RPLND), and risk factor assessment was performed within a multicenter protocol. One hundred sixty-five patients had an adequate minimum follow-up of 12 months (mean, 34.5 months) or had pathologic stage II. RESULTS: Pathologic stage II disease was found in 27.9% of patients. Only 0.6% of patients relapsed in the retroperitoneum after confirmation of pathologic stage I disease. With reference pathology, vascular invasion (VI) was most predictive of stage in multifactorial analysis (accuracy, 65.1%). However, the positive predictive value (PPV) of VI to predict patients who have metastatic disease or relapse during follow-up was only 52.7%. With absent VI, low-risk patients had a negative predictive value (NPV) of 76.9%. With a combination of several risk factors, the PPV increased to 63.6% and the negative predictive value increased to 86.5%. CONCLUSION: Even with an optimal combination of prognostic factors and reference pathology, more than one third of patients predicted to have pathologic stage II or relapse during follow-up will not harbor metastatic disease and, therefore, would be overtreated with adjuvant therapy. However, patients at low risk may be predicted at an 86.5% level, and thus, surveillance in highly compliant patients would be a valuable option. For high-risk patients, further reduction of adjuvant treatment is necessary.  相似文献   
34.
35.
36.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Schulungsmaterial für Heilberufler und Patienten stellt eine wichtige Hilfe bei der sicheren Anwendung bestimmter...  相似文献   
37.
Using an iterative structure–activity relationship driven approach, we identified a CNS-penetrant 5-(trifluoromethyl)-1,2,4-oxadiazole (TFMO, 12) with a pharmacokinetic profile suitable for probing class IIa histone deacetylase (HDAC) inhibition in vivo. Given the lack of understanding of endogenous class IIa HDAC substrates, we developed a surrogate readout to measure compound effects in vivo, by exploiting the >100-fold selectivity compound 12 exhibits over class I/IIb HDACs. We achieved adequate brain exposure with compound 12 in mice to estimate a class I/IIb deacetylation EC50, using class I substrate H4K12 acetylation and global acetylation levels as a pharmacodynamic readout. We observed excellent correlation between the compound 12 in vivo pharmacodynamic response and in vitro class I/IIb cellular activity. Applying the same relationship to class IIa HDAC inhibition, we estimated the compound 12 dose required to inhibit class IIa HDAC activity, for use in preclinical models of Huntington’s disease.  相似文献   
38.
Artificial neural networks (ANNs) were used for voxel‐wise parameter estimation with the combined intravoxel incoherent motion (IVIM) and kurtosis model facilitating robust diffusion parameter mapping in the human brain. The proposed ANN approach was compared with conventional least‐squares regression (LSR) and state‐of‐the‐art multi‐step fitting (LSR‐MS) in Monte‐Carlo simulations and in vivo in terms of estimation accuracy and precision, number of outliers and sensitivity in the distinction between grey (GM) and white (WM) matter. Both the proposed ANN approach and LSR‐MS yielded visually increased parameter map quality. Estimations of all parameters (perfusion fraction f, diffusion coefficient D, pseudo‐diffusion coefficient D*, kurtosis K) were in good agreement with the literature using ANN, whereas LSR‐MS resulted in D* overestimation and LSR yielded increased values for f and D*, as well as decreased values for K. Using ANN, outliers were reduced for the parameters f (ANN, 1%; LSR‐MS, 19%; LSR, 8%), D* (ANN, 21%; LSR‐MS, 25%; LSR, 23%) and K (ANN, 0%; LSR‐MS, 0%; LSR, 15%). Moreover, ANN enabled significant distinction between GM and WM based on all parameters, whereas LSR facilitated this distinction only based on D and LSR‐MS on f, D and K. Overall, the proposed ANN approach was found to be superior to conventional LSR, posing a powerful alternative to the state‐of‐the‐art method LSR‐MS with several advantages in the estimation of IVIM–kurtosis parameters, which might facilitate increased applicability of enhanced diffusion models at clinical scan times.  相似文献   
39.
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   
40.
Recruitment of DNA methyltransferase I to DNA repair sites   总被引:2,自引:0,他引:2  
In mammalian cells, the replication of genetic and epigenetic information is directly coupled; however, little is known about the maintenance of epigenetic information in DNA repair. Using a laser microirradiation system to introduce DNA lesions at defined subnuclear sites, we tested whether the major DNA methyltransferase (Dnmt1) or one of the two de novo methyltransferases (Dnmt3a, Dnmt3b) are recruited to sites of DNA repair in vivo. Time lapse microscopy of microirradiated mammalian cells expressing GFP-tagged Dnmt1, Dnmt3a, or Dnmt3b1 together with red fluorescent protein-tagged proliferating cell nuclear antigen (PCNA) revealed that Dnmt1 and PCNA accumulate at DNA damage sites as early as 1 min after irradiation in S and non-S phase cells, whereas recruitment of Dnmt3a and Dnmt3b was not observed. Deletion analysis showed that Dnmt1 recruitment was mediated by the PCNA-binding domain. These data point to a direct role of Dnmt1 in the restoration of epigenetic information during DNA repair.  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