全文获取类型
收费全文 | 22488篇 |
免费 | 2236篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 298篇 |
儿科学 | 771篇 |
妇产科学 | 579篇 |
基础医学 | 3215篇 |
口腔科学 | 704篇 |
临床医学 | 2773篇 |
内科学 | 4077篇 |
皮肤病学 | 399篇 |
神经病学 | 1947篇 |
特种医学 | 858篇 |
外科学 | 2902篇 |
综合类 | 544篇 |
一般理论 | 9篇 |
预防医学 | 2294篇 |
眼科学 | 380篇 |
药学 | 1702篇 |
中国医学 | 28篇 |
肿瘤学 | 1277篇 |
出版年
2021年 | 387篇 |
2020年 | 221篇 |
2019年 | 381篇 |
2018年 | 452篇 |
2017年 | 341篇 |
2016年 | 369篇 |
2015年 | 382篇 |
2014年 | 577篇 |
2013年 | 833篇 |
2012年 | 1055篇 |
2011年 | 1125篇 |
2010年 | 722篇 |
2009年 | 587篇 |
2008年 | 1100篇 |
2007年 | 1066篇 |
2006年 | 1087篇 |
2005年 | 976篇 |
2004年 | 930篇 |
2003年 | 854篇 |
2002年 | 855篇 |
2001年 | 643篇 |
2000年 | 660篇 |
1999年 | 545篇 |
1998年 | 281篇 |
1997年 | 215篇 |
1996年 | 227篇 |
1995年 | 216篇 |
1994年 | 199篇 |
1993年 | 228篇 |
1992年 | 453篇 |
1991年 | 433篇 |
1990年 | 424篇 |
1989年 | 445篇 |
1988年 | 435篇 |
1987年 | 344篇 |
1986年 | 358篇 |
1985年 | 397篇 |
1984年 | 271篇 |
1983年 | 219篇 |
1982年 | 170篇 |
1981年 | 167篇 |
1979年 | 211篇 |
1978年 | 188篇 |
1977年 | 202篇 |
1976年 | 172篇 |
1975年 | 166篇 |
1974年 | 173篇 |
1973年 | 184篇 |
1972年 | 169篇 |
1971年 | 165篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
Understanding the contribution of endothelial cells to the progenitor pools of adult tissues has the potential to inform therapies for human disease.To address whether endothelial cells transdifferentiate into non-vascular cell types,we performed cell lineage tracing analysis using transgenic mice engineered to express a fluorescent marker following activation by tamoxifen in vascular endothelial cadherin promoter-expressing cells(VEcad-CreERT2;B6 Cg-Gt(ROSA)26Sortm9(CAG-tdTomato)Hze).Activation of target-cell labeling following 1.5 months of ad libitum feeding with tamoxifen-laden chow in 4–5 month-old mice resulted in the tracing of central nervous system and peripheral cells that include:cerebellar granule neurons,ependymal cells,skeletal myocytes,pancreatic beta cells,pancreatic acinar cells,tubular cells in the renal cortex,duodenal crypt cells,ileal crypt cells,and hair follicle stem cells.As Nestin expression has been reported in a subset of endothelial cells,Nes-CreERT2 mice were also utilized in these conditions.The tracing of cells in adult Nes-CreERT2 mice revealed the labeling of canonical progeny cell types such as hippocampal and olfactory granule neurons as well as ependymal cells.Interestingly,Nestin tracing also labeled skeletal myocytes,ileal crypt cells,and sparsely marked cerebellar granule neurons.Our findings provide support for endothelial cells as active contributors to adult tissue progenitor pools.This information could be of particular significance for the intravenous delivery of therapeutics to downstream endothelial-derived cellular targets.The animal experiments were approved by the Boise State University Institute Animal Care and Use Committee(approval No.006-AC15-018)on October 31,2018. 相似文献
4.
5.
Phantana-angkool April Voci Amy E. Warren Yancey E. Livasy Chad A. Beasley Lakesha M. Robinson Myra M. Hadzikadic-Gusic Lejla Sarantou Terry Forster Meghan R. Sarma Deba White Richard L. 《Annals of surgical oncology》2019,26(12):3874-3882
Annals of Surgical Oncology - The role of sentinel lymph node biopsy (SLNB) when ductal carcinoma in situ with microinvasion (DCISM) is identified on core biopsy is unclear. Our aim was to assess... 相似文献
6.
7.
Analyzing and shaping human attentional networks. 总被引:12,自引:0,他引:12
In this paper we outline a conception of attentional networks arising from imaging studies as connections between activated brain areas carrying out localized mental operations. We consider both the areas of functional activation (nodes) and the structural (DTI) and functional connections (DCM) between them in real time (EEG, frequency analysis) as important tools in analyzing the network. The efficiency of network function involves the time course of activation of nodes and their connectivity to other areas of the network. We outline landmarks in the development of brain networks underlying executive attention from infancy and childhood. We use individual differences in network efficiency to examine genetic alleles that are related to performance. We consider how animal studies might be used to determine the genes that influence network development. Finally we indicate how training may aid in enhancing attentional networks. Our goal is to show the wide range of methods that can be used to suggest and analyze models of network function in the study of attention. 相似文献
8.
9.
Using indirect immunohistochemistry and an antiserum raised against rat corticotrophin-releasing factor (CRF) we have outlined an asymmetric network of cells and varicose fibers in sheep adrenal cortex. This network was not associated with the larger splanchnic nerves, but was occasionally found in small bundles or with blood vessels; in most instances fibers were found weaving independently through cortical parenchyma. A plexus of fibers was found in the zona reticularis, with a few fibers ramifying into adjacent medulla. Uni or bipolar cells were found throughout the cortex, with the greatest frequency at the corticomedullary junction; a multipolar-type cell was also found in this area. Staining of varicose structures and most cells was abolished by incubation with excess rat CRF 1-41, but not by ovine CRF or a range of other peptides. Though the immunoreactive species has not as yet been identified, it may thus share homology with sequences present in rat but not ovine CRF. 相似文献
10.
The use of additional epidural sympathetic block during and after microvascular surgery in the lower extremities to prevent vasospasm is generally agreed on. However, a significant fall in the perfusion rate of the transplants was seen after application of bupivacaine (Marcain) via the epidural catheter. This effect has, to our knowledge, not been described before and is probably caused by the sympathectomy effect of this type of analgesia. 相似文献