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   334篇
  免费   29篇
耳鼻咽喉   1篇
儿科学   8篇
妇产科学   7篇
基础医学   51篇
口腔科学   2篇
临床医学   31篇
内科学   82篇
皮肤病学   2篇
神经病学   54篇
特种医学   21篇
外科学   18篇
综合类   1篇
预防医学   19篇
眼科学   21篇
药学   22篇
中国医学   3篇
肿瘤学   20篇
  2023年   3篇
  2022年   6篇
  2021年   21篇
  2020年   13篇
  2019年   14篇
  2018年   13篇
  2017年   9篇
  2016年   18篇
  2015年   14篇
  2014年   16篇
  2013年   12篇
  2012年   27篇
  2011年   26篇
  2010年   16篇
  2009年   8篇
  2008年   9篇
  2007年   29篇
  2006年   13篇
  2005年   30篇
  2004年   18篇
  2003年   12篇
  2002年   11篇
  2001年   3篇
  2000年   3篇
  1999年   2篇
  1998年   5篇
  1997年   4篇
  1996年   2篇
  1995年   1篇
  1992年   2篇
  1988年   1篇
  1983年   1篇
  1981年   1篇
排序方式: 共有363条查询结果,搜索用时 27 毫秒
81.
82.
83.
The results of several recent studies suggest that human umbilical cord blood (HUCB)-derived cells have the potential to undergo neural differentiation both in vitro and in vivo. Transplantation into the embryonic ventricular zone provides a unique opportunity to study the migration and differentiation of nonneural somatic progenitor cells in response to instructive cues within the developing neuroepithelium. We isolated an adherently growing population of HUCB-derived cells expressing CD13, CD29, CD49e, CD71, CD73, CD166, Flk-1, and vimentin but lacking CD34 and CD45. On transplantation into the ventricles of embryonic day 16.5 rat embryos, these cells formed subventricular clusters that extended into a variety of host brain regions, including striatum, cortex, hippocampus, thalamus, hypothalamus, tectum, pons, and cerebellum. Donor cells identified with an antibody to human nuclei or human-specific DNA in situ hybridization maintained expression of their original marker antigens and showed no expression of the neural markers MAP2 and NeuN (neurons), GFAP (astrocytes), and CNP (oligodendrocytes). In contrast to grafted primary neural cells, they remained largely confined to subventricular clusters with little evidence for intraparenchymal integration. Thus, the neurogenic environment of the embryonic ventricular zone does not promote the elaboration of a neural phenotype in HUCB-derived cells.  相似文献   
84.
To better characterize acute myeloid leukemia (AML) development in non-obese diabetic (NOD)/severe combined immunodeficiency (SCID) mice, we transplanted samples from patients with AML or KG-1 and EOL-1 cell lines. We found 9/12 primary AML samples and both cell lines to engraft within 2-8 weeks, with 5-80% human cells in bone marrow. Compared with freshly isolated AML cells, percentages of human CD33+, CD38+, CD31+ CD13+ or CD15+ subpopulations increased after transplantation, whereas percentages of CD34+ cells decreased. Engrafted mice frequently showed expression of human endothelial cell markers. Thus, transplantation of human AML into NOD/SCID mice reveals expression of hematopoietic and endothelial differentiation markers.  相似文献   
85.
86.
Making routine clinical-care-data available for medical research requires adequate consent to legitimize use and exchange. While, public interest in supporting medical research is increasing, individuals often find it difficult to actively enable researchers to access their data. In addition to broad consent, the idea of (consent-free) data donation has been brought into play as another way to legitimize secondary research use of medial data. However, flanking the implementation of broad consent policies or data donation, the attitude of patients, and the general public toward different aspects of these approaches needs to be assessed. We conducted two empirical studies to this end among Dutch patients (n = 7430) and representative German citizens (n = 1006). Wide acceptance of broad consent was observed among Dutch patients (92.3%), corroborating previous findings among German patients (93.0%). Moreover, 28.8% of the Dutch patients generally approved secondary data-use for non-academic research, 42.3% would make their decision dependent upon the type of institution in question. In the German survey addressing the general population, 78.8% approved data donation without explicit consent as an alternative model of legitimization, the majority of those who approved (96.7%) would allow donated data to be used by universities and public research institutions. This willingness to support contrasted sharply with the fact that only 16.6% would allow access to the data by industry. Our findings thus not only add empirical evidence to the debate about broad consent and data donation, but also suggest that widespread public discussion and education about the role of industry in medical research is necessary in that context.Subject terms: Medical research, Social sciences  相似文献   
87.
Summary To study morphogenetic events of rotavirus SA11-infected MA104 cells with strictly defined reagents we produced monoclonal antibodies against synthetic peptides from both outer capsid proteins VP4 (aa residues 228–241: QNTRNIVPVSIVSR) and VP7 (aa residues 319–326: SAAFYYRV) of simian rotavirus SA11. Two of the selected monoclonal antibodies proved to be reactive with determinants of SA11-infected MA104 rhesus monkey kidney cells, with purified SA11 as well as with the particular peptides used for immunization. The anti-VP4 antibody had a demonstrable neutralizing titer of 200 (50% focus reduction) whereas the anti-VP7 MuMAb revealed no detectable neutralizing activity. In peptide-inhibition experiments, the corresponding peptide inhibited its MuMAb whereas the noncorresponding peptide had no effect on antibody binding to intracellular viral antigen. Localization of VP7 was preceded by VP4 as shown by immunofluorescence microscopy.  相似文献   
88.
Two types of photoreceptors, rods and cones, coexist in the vertebrate retina. An in-depth analysis of the retinal circuitry that transmits rod and cone signals has been hampered by the presence of intimate physical and functional connections between rod and cone pathways. By deleting the cyclic nucleotide-gated channel CNG3 we have generated a mouse lacking any cone-mediated photoresponse. In contrast, the rod pathway is completely intact in CNG3-deficient mice. The functional loss of cone function correlates with a progressive degeneration of cone photoreceptors but not of other retinal cell types. CNG3-deficient mice provide an animal model to dissect unequivocally the contribution of rod and cone pathways for normal retinal function.  相似文献   
89.
90.
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