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   1006篇
  免费   67篇
  国内免费   20篇
耳鼻咽喉   7篇
儿科学   58篇
妇产科学   11篇
基础医学   123篇
口腔科学   54篇
临床医学   76篇
内科学   187篇
皮肤病学   25篇
神经病学   53篇
特种医学   112篇
外科学   88篇
综合类   12篇
预防医学   73篇
眼科学   20篇
药学   86篇
中国医学   3篇
肿瘤学   105篇
  2023年   4篇
  2022年   6篇
  2021年   16篇
  2020年   10篇
  2019年   29篇
  2018年   23篇
  2017年   13篇
  2016年   20篇
  2015年   23篇
  2014年   23篇
  2013年   48篇
  2012年   38篇
  2011年   41篇
  2010年   40篇
  2009年   44篇
  2008年   34篇
  2007年   48篇
  2006年   40篇
  2005年   41篇
  2004年   37篇
  2003年   33篇
  2002年   29篇
  2001年   17篇
  2000年   30篇
  1999年   25篇
  1998年   34篇
  1997年   36篇
  1996年   35篇
  1995年   29篇
  1994年   26篇
  1993年   22篇
  1992年   19篇
  1991年   12篇
  1990年   18篇
  1989年   18篇
  1988年   20篇
  1987年   13篇
  1986年   18篇
  1985年   15篇
  1984年   9篇
  1983年   7篇
  1982年   12篇
  1981年   7篇
  1980年   5篇
  1978年   3篇
  1977年   2篇
  1976年   3篇
  1975年   6篇
  1974年   2篇
  1973年   3篇
排序方式: 共有1093条查询结果,搜索用时 15 毫秒
31.

Objective

To determine the acceptability of self-collected versus provider-collected sampling among women participating in public sector HPV-based cervical cancer screening in El Salvador.

Methods

Two thousand women aged 30–49 years underwent self-collected and provider-collected sampling with careHPV between October 2012 and March 2013 (Qiagen, Gaithersburg, MD, USA). After sample collection, a random sample of women (n = 518) were asked about their experience. Participants were questioned regarding sampling method preference, previous cervical cancer screening, HPV and cervical cancer knowledge, HPV risk factors, and demographic information.

Results

All 518 women approached to participate in this questionnaire study agreed and were enrolled, 27.8% (142 of 511 responding) of whom had not received cervical cancer screening within the past 3 years and were considered under-screened. Overall, 38.8% (n = 201) preferred self-collection and 31.9% (n = 165) preferred provider collection. Self-collection preference was associated with prior tubal ligation, HPV knowledge, future self-sampling preference, and future home-screening preference (P < 0.05). Reasons for self-collection preference included privacy/embarrassment, ease, and less pain; reasons cited for provider-collection preference were result accuracy and provider knowledge/experience.

Conclusion

Self-sampling was found to be acceptable, therefore screening programs could consider offering this option either in the clinic or at home. Self-sampling at home may increase coverage in low-resource countries and reduce the burden that screening places upon clinical infrastructure.  相似文献   
32.
The Eph and ephrin families are involved in numerous developmental processes. Recently, an increasing body of evidence has related these families with some aspects of T cell development. In the present study, we show that the addition of either EphB2-Fc or ephrinB1-Fc fusion proteins to fetal thymus organ cultures established from 17-day-old fetal mice decreases the numbers of both double-positive (CD4(+)CD8(+)) and single-positive (both CD4(+)CD8(-) and CD4(-)CD8(+)) thymocytes, in correlation with increased apoptosis. By using reaggregate thymus organ cultures formed by fetal thymic epithelial cells (TEC) and CD4(+)CD8(+) thymocytes, we have also demonstrated that ephrinB1-Fc proteins are able to disorganize the three-dimensional epithelial network that in vivo supports the T cell maturation, and to alter the thymocyte interactions. In addition, in an in vitro model, Eph/ephrinB-Fc treatment also decreases the formation of cell conjugates by CD4(+)CD8(+) thymocytes and TEC as well as the TCR-dependent signaling between both cell types. Finally, immobilized EphB2-Fc and ephrinB1-Fc modulate the anti-CD3 antibody-induced apoptosis of CD4(+)CD8(+) thymocytes in a process dependent on concentration. These results therefore support a role for Eph/ephrinB in the processes of development and selection of thymocytes as well as in the establishment of the three-dimensional organization of TEC.  相似文献   
33.
In vivo observations on the kinetics of F cells and of fetal hemoglobin (HbF) synthesis and in vitro studies of erythroid progenitors, their number, and the gamma-gene expression in their progeny were carried out in baboons (Papio cynocephalus) treated with 5-azacytidine. Maximum effect on the increase of HbF production in vivo was observed only when an expanded erythroid marrow population was present. In these animals, as well as in normal animals, treatment resulted in a significant reduction of the late erythroid progenitor cell pools (erythroid clusters and erythroid colony-forming units, CFU-E) in the marrow. This reduction was more pronounced among those progenitors grown in the absence of added erythropoietin, and it was followed by a rebound a few days after treatment cessation, reflecting the accumulation of regenerating progenitors. An early increase in the in vitro synthesis of HbF in erythroid clusters and CFU-E colonies was observed. This increase was further documented at the cellular level, with immunofluorescent labeling of colonies with monoclonal anti-gamma- globin chain antibodies. In contrast to the findings in late progenitors, the number of erythroid burst-forming unit (BFU-E) colonies and the synthesis of HbF in these colonies was not influenced significantly by 5-azacytidine treatment. It is proposed that the toxic effects of 5-azacytidine on late progenitors, leading to faster mobilization of earlier progenitors to the next more mature compartment, play a role in the in vivo augmentation of HbF synthesis by this drug. This perturbation in the progenitor cell population kinetics and the presumed hypomethylation of the surviving differentiating cells may act synergistically to produce a maximum HbF response after 5-azacytidine treatment.  相似文献   
34.
35.
36.
Peripheral T-cell lymphomas consist of a clinically heterogeneous group of malignant disorders whose immunophenotype usually corresponds to that of normal mature T cells. We describe and correlate the clinical, histopathologic, phenotypic, and genotypic findings in two patients with malignant lymphoma presenting with hepatosplenic disease. The morphologic pattern of lymphoma was that of a sinusal/sinusoidal infiltration in spleen, marrow, and liver. This morphologic characteristic was associated with the presence of a productive clonal rearrangement of the T-cell receptor (TCR) delta gene. Lymphoma cells expressed a CD3-TCR-gamma delta- phenotype. They were also double negative (ie, CD4-CD8-) and lacked the CD5 and CD7 antigens. In one patient, tumor progression was associated with phenotypic changes that resulted in a CD3-TCR-gamma delta- phenotype with the same delta-gene rearrangement as initially. These observations suggest the existence of a new type of peripheral T-cell lymphoma characterized by its hepatosplenic presentation, and by the sinusal/sinusoidal tropism and the TCR-gamma delta phenotype of the malignant cells.  相似文献   
37.
38.
39.
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.  相似文献   
40.
The use of a fully digital approach to fabricate an anatomic contour crown to fit an existing removable prosthesis allows the dentist and the dental laboratory technician to work efficiently in a digital environment. This report presents a series of patient treatments involving the fabrication of an anatomic contour monolithic zirconia crown to retrofit an existing removable partial denture. A complete digital workflow comprises an intraoral digital scan and computer-aided design and computer-aided manufacturing (CAD-CAM) technology.  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