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   127726篇
  免费   13205篇
  国内免费   7012篇
耳鼻咽喉   997篇
儿科学   2410篇
妇产科学   1545篇
基础医学   31589篇
口腔科学   3578篇
临床医学   9816篇
内科学   18821篇
皮肤病学   2212篇
神经病学   9398篇
特种医学   2583篇
外国民族医学   30篇
外科学   11388篇
综合类   19289篇
现状与发展   35篇
一般理论   2篇
预防医学   3650篇
眼科学   3221篇
药学   12278篇
  19篇
中国医学   4485篇
肿瘤学   10597篇
  2024年   81篇
  2023年   1598篇
  2022年   2146篇
  2021年   3901篇
  2020年   3962篇
  2019年   3649篇
  2018年   3756篇
  2017年   4271篇
  2016年   4823篇
  2015年   5383篇
  2014年   8272篇
  2013年   10234篇
  2012年   7818篇
  2011年   9138篇
  2010年   7453篇
  2009年   7092篇
  2008年   7277篇
  2007年   7371篇
  2006年   6787篇
  2005年   5855篇
  2004年   4929篇
  2003年   4089篇
  2002年   3096篇
  2001年   2624篇
  2000年   2246篇
  1999年   1804篇
  1998年   1533篇
  1997年   1432篇
  1996年   1292篇
  1995年   1497篇
  1994年   1374篇
  1993年   1186篇
  1992年   971篇
  1991年   894篇
  1990年   800篇
  1989年   787篇
  1988年   669篇
  1987年   593篇
  1986年   520篇
  1985年   782篇
  1984年   696篇
  1983年   494篇
  1982年   617篇
  1981年   483篇
  1980年   431篇
  1979年   352篇
  1978年   239篇
  1977年   185篇
  1976年   171篇
  1975年   62篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
3.
Objective: Animal environments for the growth of stem cells cause the transmission of some diseases and immune problems for the recipient. Accordingly, replacing these environments with healthy environments, at least with human resources, is essential.  One of the media that can be used as an alternative to animal serums is Wharton acellular jelly (AWJ).  Therefore, in this study, we intend to replace FBS with Wharton jelly and investigate its effect on the expression of megakaryocyte-related genes and markers in stem cells. Materials and Methods: In this study, cord blood-derived CD34 positive HSCs were cultured and expanded in the presence of cytokines including SCF, TPO, and FLT3-L. Then, the culture of expanded CD34 positive HSCs was performed in two groups: 1) IMDM culture medium containing 10% FBS and 100 ng / ml thrombopoietin cytokine 2) IMDM culture medium containing 10% AWJ, 100 ng / ml thrombopoietin cytokine.  Finally, CD41 expressing cells were analyzed with the flow cytometry method. The genes related to megakaryocyte lineage including FLI1 and GATA2 were also evaluated using the RT-PCR technique.  Results: The expression of CD41, a specific marker of megakaryocyte lineage in culture medium containing Wharton acellular jelly was increased compared to the FBS group. Additionally, the expression of GATA2 and FLI1 genes was significantly increased related to the control group. Conclusion: This study provided evidence of differentiation of CD34 positive hematopoietic stem cells from umbilical cord blood to megakaryocytes in a culture medium containing AWJ.  相似文献   
4.
外泌体是一类直径为30~100 nm的圆盘囊泡,其内包含许多组分,诸如复杂RNA和蛋白质等,主要参与细胞间的信号转导。肿瘤相关巨噬细胞(tumor-associated macrophages,TAMs)是肿瘤微环境中普遍存在的巨噬细胞,通过对肿瘤生长、免疫逃逸、侵袭和转移、耐药性等多方面的作用影响肿瘤进程。外泌体在肿瘤相关巨噬细胞的招募、极化及抗肿瘤免疫调控等方面发挥着重要的调节功能。同时,TAMs以外泌体为媒介作用于肿瘤细胞,从而构成了外泌体、TAMs与肿瘤细胞之间相互作用的调控通路。综上所述,本文旨在阐明肿瘤细胞与TAMs之间,以外泌体为“桥梁”相互影响的潜在机制,以及靶向肿瘤细胞和TAMs来源的外泌体在恶性肿瘤治疗中的展望。  相似文献   
5.
6.
7.
8.
9.
Transfusion related acute lung injury (TRALI) is a rare but potentially fatal pulmonary complication of transfusion that presents as acute hypoxemia and non-cardiogenic pulmonary oedema, developing during or within six hours of transfusion. Majority of the cases reported are due to transfusion of plasma rich blood components containing antibodies to human leukocyte antigen (anti-HLA) or human neutrophil antigen (anti-HNA). Rarely, anti-HLA or anti-HNA in recipients against transfused donor leukocyte antigens, cause TRALI by a reverse mechanism. Herein, we report three cases of suspected TRALI following transfusions of buffy coat derived granulocytes and peripheral blood stem cells. Three patients with hematological malignancies developed pulmonary symptoms after transfusions of leukocyte rich blood components. All cases showed findings of bilateral pulmonary infiltrates at chest radiography and patients were managed accordingly; however, all three expired within seven days of transfusion due to progressive respiratory deterioration. The patients were transfusion dependent for a long time and had received multiple non-leukoreduced blood components in the past. Clinical findings in all three cases indicate the possibility of reverse TRALI. Although, patients’ anti-HLA or anti-HNA antibodies concordance with donors’ cognate antigens (HLA and HNA) was not confirmed; yet these three cases suggest that reverse pathogenesis of TRALI is not as infrequent as reported in the literature. However, reverse TRALI has not been confirmed as the presence and nature of antibodies in the transfused recipient were not investigated due to the non availability of immunodiagnostic tests in India.  相似文献   
10.
《Molecular therapy》2022,30(6):2186-2198
  1. Download : Download high-res image (179KB)
  2. Download : Download full-size image
  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