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   4529篇
  免费   224篇
  国内免费   49篇
耳鼻咽喉   69篇
儿科学   71篇
妇产科学   93篇
基础医学   622篇
口腔科学   110篇
临床医学   415篇
内科学   768篇
皮肤病学   150篇
神经病学   322篇
特种医学   203篇
外科学   581篇
综合类   32篇
一般理论   3篇
预防医学   243篇
眼科学   67篇
药学   577篇
中国医学   110篇
肿瘤学   366篇
  2023年   33篇
  2022年   114篇
  2021年   183篇
  2020年   90篇
  2019年   116篇
  2018年   143篇
  2017年   106篇
  2016年   140篇
  2015年   197篇
  2014年   255篇
  2013年   277篇
  2012年   391篇
  2011年   404篇
  2010年   222篇
  2009年   169篇
  2008年   270篇
  2007年   256篇
  2006年   225篇
  2005年   190篇
  2004年   165篇
  2003年   140篇
  2002年   109篇
  2001年   98篇
  2000年   78篇
  1999年   82篇
  1998年   33篇
  1997年   18篇
  1996年   22篇
  1995年   11篇
  1994年   9篇
  1993年   8篇
  1992年   31篇
  1991年   29篇
  1990年   26篇
  1989年   22篇
  1988年   11篇
  1987年   12篇
  1986年   5篇
  1985年   17篇
  1984年   5篇
  1983年   6篇
  1979年   5篇
  1974年   8篇
  1972年   5篇
  1971年   8篇
  1970年   4篇
  1969年   6篇
  1968年   14篇
  1967年   5篇
  1966年   4篇
排序方式: 共有4802条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Cellular senescence is known to contribute to tissue aging, a variety of age-related diseases, tissue regeneration, and cancer. Therefore, aging intervention might be useful for prevention of aging as well as age-related disease. In this study, we investigated compounds from Polygonum aviculare to determine if they inhibited cellular senescence in human primary cells, human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs). Ten compounds from P. aviculare were purified and their inhibitory effects on adriamycin-induced cellular senescence were measured by observing senescence-associated β-galactosidase (SA-β-gal) activity and reactive oxygen species. Among them, compound 9 (quercetin-3-O-β-d-glucuronide) showed inhibitory effects against cellular senescence in HDFs and HUVECs treated with adriamycin. Additionally, compound 9 rescued replicative senescence in HDFs and HUVECs. These data imply that compound 9 represses cellular senescence in human primary cells and might be useful for the development of dietary supplements or cosmetics that ameliorate tissue aging or aging-associated diseases.  相似文献   
95.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, is a readily transmissible and potentially deadly pathogen which is currently re-defining human susceptibility to pandemic viruses in the modern world. The recent emergence of several genetically distinct descendants known as variants of concern (VOCs) is further challenging public health disease management, due to increased rates of virus transmission and potential constraints on vaccine effectiveness. We report the isolation of SARS-CoV-2 VOCs imported into Australia belonging to the B.1.351 lineage, first described in the Republic of South Africa (RSA), and the B.1.1.7 lineage originally reported in the United Kingdom, and directly compare the replication kinetics of these two VOCs in Vero E6 cells. In this analysis, we also investigated a B.1.1.7 VOC (QLD1516/2021) carrying a 7-nucleotide deletion in the open reading frame 7a (ORF7a) gene, likely truncating and rendering the ORF7a protein of this virus defective. We demonstrate that the replication of the B.1.351 VOC (QLD1520/2020) in Vero E6 cells can be detected earlier than the B.1.1.7 VOCs (QLD1516/2021 and QLD1517/2021), before peaking at 48 h post infection (p.i.), with significantly higher levels of virus progeny. Whilst replication of the ORF7a defective isolate QLD1516/2021 was delayed longer than the other viruses, slightly more viral progeny was produced by the mutant compared to the unmutated isolate QLD1517/2021 at 72 h p.i. Collectively, these findings contribute to our understanding of SARS-CoV-2 replication and evolutionary dynamics, which have important implications in the development of future vaccination, antiviral therapies, and epidemiological control strategies for COVID-19.  相似文献   
96.
97.
Sleep and Breathing - To study changes in lung function among individuals with a risk of obstructive sleep apnoea (OSA), and if asthma affected this relationship. We used data from the European...  相似文献   
98.
Kim  Hye Jin  Park  Mi-Suk  Son  Jin Woo  Han  Kyunghwa  Lee  Jei Hee  Kim  Jai Keun  Paik  Hyo Chae 《Abdominal imaging》2019,44(4):1361-1366
Abdominal Radiology - The purpose of this study was to investigate the radiological patterns of secondary sclerosing cholangitis (SSC) following lung transplantation. Fifty-five patients underwent...  相似文献   
99.
Seven-band grouper, Epinephelus septemfasciatus, is of considerable economic value and a candidate species of aquaculture in Eastern Asia. It is necessary to monitor the stocks for the sustainable use and aquaculture of the species. Monitoring genetic variation among marine resources necessitates the development of genetic markers. Here, we report 22 polymorphic microsatellite markers with 2–16 alleles per locus. The mean observed and expected heterozygosity per locus was 0.53 and 0.57, respectively. Cross-amplification revealed variability in Epinephelus bruneus and Epinephelus akaara. The 22 markers developed can be a valuable tool for genetic conservation of this species.  相似文献   
100.
Cauda equina syndrome (CES) associated with dural ectasia is a rare neurologic complication in patients with longstanding ankylosing spondylitis (AS). We report a 68-year-old male with a 30-year history of AS who presented a typical symptom and signs of progressive CES, urinary incontinence and neuropathic pain of the lumbosacral radiculopathy. Computed tomography (CT) and magnetic resonance imaging (MRI) findings showed the unique appearances of dural ectasia, multiple dural diverticula, erosion of posterior element of the lumbar spine, tethering of the conus medullaris and adhesion of the lumbosacral nerve roots to the posterior aspect of the dural ectasia. Considering the progressive worsening of the clinical signs, detethering of the conus medullaris through resection of the filum terminale was performed through a limited laminectomy. However, the urinary incontinence did not improve and there was a partial relief of the neuropathic leg pain only. The possible pathogenetic mechanism of CES-AS and the dural ectasia in this patient with longstanding AS are discussed with a literature review.  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