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   5608篇
  免费   387篇
  国内免费   102篇
  2024年   7篇
  2023年   73篇
  2022年   48篇
  2021年   121篇
  2020年   137篇
  2019年   193篇
  2018年   210篇
  2017年   104篇
  2016年   155篇
  2015年   169篇
  2014年   365篇
  2013年   465篇
  2012年   290篇
  2011年   372篇
  2010年   320篇
  2009年   276篇
  2008年   325篇
  2007年   352篇
  2006年   304篇
  2005年   300篇
  2004年   236篇
  2003年   233篇
  2002年   165篇
  2001年   94篇
  2000年   95篇
  1999年   92篇
  1998年   64篇
  1997年   80篇
  1996年   60篇
  1995年   49篇
  1994年   48篇
  1993年   33篇
  1992年   35篇
  1991年   22篇
  1990年   18篇
  1989年   15篇
  1988年   9篇
  1987年   9篇
  1985年   19篇
  1984年   27篇
  1983年   17篇
  1982年   16篇
  1981年   10篇
  1980年   7篇
  1979年   10篇
  1978年   11篇
  1977年   11篇
  1976年   7篇
  1975年   5篇
  1974年   6篇
排序方式: 共有6097条查询结果,搜索用时 15 毫秒
41.
《Cell reports》2020,30(5):1504-1514.e7
  1. Download : Download high-res image (117KB)
  2. Download : Download full-size image
  相似文献   
42.
《Cell reports》2020,30(6):1898-1909.e4
  1. Download : Download high-res image (132KB)
  2. Download : Download full-size image
  相似文献   
43.
《Cell reports》2020,30(1):112-123.e4
  1. Download : Download high-res image (131KB)
  2. Download : Download full-size image
  相似文献   
44.
45.
The foreign body reaction occurs when a synthetic surface is introduced to the body. It is characterized by adsorption of blood proteins and the subsequent attachment and activation of platelets, monocyte/macrophage adhesion, and inflammatory cell signaling events, leading to post-procedural complications. The Chandler Loop Apparatus is an experimental system that allows researchers to study the molecular and cellular interactions that occur when large volumes of blood are perfused over polymeric conduits. To that end, this apparatus has been used as an ex vivo model allowing the assessment of the anti-inflammatory properties of various polymer surface modifications. Our laboratory has shown that blood conduits, covalently modified via photoactivation chemistry with recombinant CD47, can confer biocompatibility to polymeric surfaces. Appending CD47 to polymeric surfaces could be an effective means to promote the efficacy of polymeric blood conduits. Herein is the methodology detailing the photoactivation chemistry used to append recombinant CD47 to clinically relevant polymeric blood conduits and the use of the Chandler Loop as an ex vivo experimental model to examine blood interactions with the CD47 modified and control conduits.  相似文献   
46.
In recent years, chimeric antigen receptor T (CAR T)-cell therapy has shown great potential in treating haematologic disease, but no breakthrough has been achieved in solid tumours. In order to clarify the antitumour mechanism of CAR T cell in solid tumours, the pharmacokinetic (PK) and pharmacodynamic (PD) investigations of CD19 CAR T cell were performed in human leukaemic xenograft mouse models. For PK investigation, we radiolabelled CD19 CAR T cell with 89Zr and used PET imaging in the CD19-positive and the CD19-negative K562-luc animal models. For PD evaluation, optical imaging, tumour volume measurement and DNA copy-number detection were performed. Unfortunately, the qPCR results of the DNA copy number in the blood were below the detection limit. The tumour-specific uptake was higher in the CD19-positive model than in the CD19-negative model, and this was consistent with the PD results. The preliminary PK and PD studies of CD19 CAR T cell in solid tumours are instructive. Considering the less efficiency of CAR T-cell therapy of solid tumours with the limited number of CAR T cells entering the interior of solid tumours, this study is suggestive for the subsequent CAR T-cell design and evaluation of solid tumour therapy.  相似文献   
47.
Abstract

An efficient synthesis of adenosine bearing pyrrolepolyamide 1 was achieved by coupling of 3 with 2. The CD spectra obtained at several [ligand ]/[duplex] ratios allowed verification of the formation complex of the DNA duplex [d(CGCAAATTGGC)/d(GCCAATTTGCG)] with 1.  相似文献   
48.
49.
Abstract Pertussis toxin (PT) inhibited luminol-enhanced chemiluminescence induced in rabbit peritoneal neutrophils by N'-formyl- l -methionyl- l -leucyl- l -phenylalanine (fMLP) at doses as low as 0.8 ng·ml−1, even in the presence of a 10-fold higher concentration of filamentous haemagglutinin (FHA). A cell-free extract of Bordetella pertusis , containing predominantly PT and FHA, suppressed the neutrophil response to fMLP. After toxoiding with carbodiimide, the inhibitory activity of the extract was abolished and an enhancement of neutrophil chemiluminescence was observed due to FHA activity. Abrogation of the chemiluminescent response of neutrophils to fMLP is proposed as a sensitive, in vitro assay for PT, and may be useful for monitoring the residual toxin activity in pertussis toxoids and for determining the anti-toxic effects of anti-PT antibodies.  相似文献   
50.
为简化转染细胞的分选过程,构建了一个含有细胞表面标志 CD34 基因的双顺反子载体 p3.1-IRES-CD34. 利用来源于脑心肌炎病毒 (EMCV) 的内部核糖体进入位点 (IRES) ,实现目的基因与 CD34 基因的共同表达 . 将绿色荧光蛋白 (EGFP) 作为目的基因插入载体的多克隆位点,然后转染 NIH-3T3 细胞,通过免疫磁珠分选 (MACS) 方法来分选细胞 . 结果表明:对于转染细胞,均可实现快速分选 ( 瞬时转染细胞约 48 h ,稳定转染 10~15 天 ) ,并且获得较高纯度 (95% 以上 ) 的表达目的基因细胞 .  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