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   5517篇
  免费   387篇
  国内免费   31篇
耳鼻咽喉   58篇
儿科学   269篇
妇产科学   119篇
基础医学   663篇
口腔科学   170篇
临床医学   560篇
内科学   1254篇
皮肤病学   69篇
神经病学   452篇
特种医学   309篇
外国民族医学   1篇
外科学   557篇
综合类   63篇
一般理论   2篇
预防医学   456篇
眼科学   71篇
药学   467篇
  1篇
中国医学   8篇
肿瘤学   386篇
  2023年   25篇
  2022年   82篇
  2021年   124篇
  2020年   106篇
  2019年   147篇
  2018年   142篇
  2017年   110篇
  2016年   135篇
  2015年   144篇
  2014年   192篇
  2013年   251篇
  2012年   349篇
  2011年   329篇
  2010年   205篇
  2009年   229篇
  2008年   316篇
  2007年   283篇
  2006年   255篇
  2005年   256篇
  2004年   245篇
  2003年   191篇
  2002年   197篇
  2001年   91篇
  2000年   75篇
  1999年   90篇
  1998年   130篇
  1997年   118篇
  1996年   109篇
  1995年   76篇
  1994年   80篇
  1993年   72篇
  1992年   58篇
  1991年   53篇
  1990年   48篇
  1989年   67篇
  1988年   53篇
  1987年   60篇
  1986年   32篇
  1985年   52篇
  1984年   42篇
  1983年   28篇
  1982年   27篇
  1981年   33篇
  1980年   17篇
  1979年   24篇
  1978年   16篇
  1977年   15篇
  1976年   21篇
  1975年   19篇
  1972年   12篇
排序方式: 共有5935条查询结果,搜索用时 31 毫秒
51.
Lymphocyte Stimulation   总被引:1,自引:0,他引:1  
  相似文献   
52.
Within the GEN-COVID Multicenter Study, biospecimens from more than 1000 SARS-CoV-2 positive individuals have thus far been collected in the GEN-COVID Biobank (GCB). Sample types include whole blood, plasma, serum, leukocytes, and DNA. The GCB links samples to detailed clinical data available in the GEN-COVID Patient Registry (GCPR). It includes hospitalized patients (74.25%), broken down into intubated, treated by CPAP-biPAP, treated with O2 supplementation, and without respiratory support (9.5%, 18.4%, 31.55% and 14.8, respectively); and non-hospitalized subjects (25.75%), either pauci- or asymptomatic. More than 150 clinical patient-level data fields have been collected and binarized for further statistics according to the organs/systems primarily affected by COVID-19: heart, liver, pancreas, kidney, chemosensors, innate or adaptive immunity, and clotting system. Hierarchical clustering analysis identified five main clinical categories: (1) severe multisystemic failure with either thromboembolic or pancreatic variant; (2) cytokine storm type, either severe with liver involvement or moderate; (3) moderate heart type, either with or without liver damage; (4) moderate multisystemic involvement, either with or without liver damage; (5) mild, either with or without hyposmia. GCB and GCPR are further linked to the GCGDR, which includes data from whole-exome sequencing and high-density SNP genotyping. The data are available for sharing through the Network for Italian Genomes, found within the COVID-19 dedicated section. The study objective is to systematize this comprehensive data collection and begin identifying multi-organ involvement in COVID-19, defining genetic parameters for infection susceptibility within the population, and mapping genetically COVID-19 severity and clinical complexity among patients.Subject terms: Genetics research, Viral infection  相似文献   
53.
A 52-year-old man presented with heart failure of 1 month duration. He had undergone aortic valve and root replacement 30 months before admission. A continuous murmur was heard in the second intercostal space at the parasternal border. Aortography showed a pseudoaneurysm surrounding the aorta, whereas color Doppler study revealed flow from the central aorta to the pseudoaneurysm and flow from the pseudoaneurysm to the pulmonary artery trunk through a fistulous communication between them. Thus, fistulous communication with pulmonary artery causing heart failure is a complication of pseudoaneurysm after aortic and root replacement, which can be diagnosed clinically and echocardiographically.  相似文献   
54.
Epstein-Barr virus (EBV) DNA load values were measured in samples of whole blood (n = 60) and plasma (n = 59) by TaqMan PCR and in samples of peripheral blood lymphocytes (PBLs) (n = 60) by competitive PCR (cPCR). The samples were obtained from 44 transplant recipients. The whole-blood and PBL loads correlated highly (r(2) > 0.900), whereas the plasma and PBL loads correlated poorly (r(2) = 0.512). Testing of whole blood by TaqMan PCR is an acceptable alternative to testing of PBLs by cPCR for quantifying EBV DNA load.  相似文献   
55.
Intestinal dendritic cells increase T cell expression of alpha4beta7 integrin   总被引:10,自引:0,他引:10  
The integrin alpha4beta7 binds to MAdCAM-1 and contributes to homing of lymphocytes to gut and other mucosal tissues. In humans, the alpha4beta7(hi) subset of circulating memory cells appears to have been primed in mucosal tissues. The factors that determine whether alpha4beta7(lo) naive cells become alpha4beta(hi) or alpha4beta7(-) cells upon differentiation are poorly understood but could include an influence of the activating antigen-presenting cell. To address this point, the induction of alpha4beta7 following activation of mouse cells with the APC-dependent stimulus soluble anti-CD3 has been examined. Almost all mouse T cells freshly isolated from mesenteric lymph nodes (MLN) and peripheral (PLN; axillary, brachial and inguinal) lymph nodes stained only weakly for alpha4beta7 but a subpopulation became alpha4beta7(hi) upon activation with anti-CD3 in a cell cycle- and accessory cell-dependent manner. A small proportion (approximately 1.5 %) of the starting cells gave rise to alpha4beta7(hi) cells after culture. A higher proportion of alpha4beta7(hi) cells were generated in MLN than PLN cultures. Peyer's patch cultures gave intermediate values. In crossover experiments, MLN dendritic cells (DC) induced higher proportions and numbers of alpha4beta7(hi) cells than PLN DC irrespective of the source of T cells. Therefore, in addition to their other immunoregulatory roles, DC have the potential to shape immune responses by influencing the homing of the lymphocytes they activate.  相似文献   
56.
Complex reciprocal interactions between hepatitis C (HCV) and hepatitis B (HBV) viruses (HBV) have been reported. We examined the influence of HBV on HCV RNA titers in 376 HCV/HIV-coinfected patients (30 were also HBsAg positive). Regression analyses identified negative HBsAg and male sex as factors associated with HCV RNA values >500,000 IU/mL.  相似文献   
57.
58.
Nineteen patients that had developed hypertrophic scars subsequent to thermal injury were typed for HLA class II allogenotypes with the restriction fragment length polymorphism technique. A significant association was found with DR beta 16 (pc = 1.45 x 10(-4); relative risk = 12.25). This finding adds evidence to other data suggesting that immunologic phenomena are involved in pathologic scarring. Moreover, the results presented here have allowed an identification of a genetically determined risk factor for hypertrophic scar formation located in the HLA region.  相似文献   
59.
Occurrence of renal involvement in Rheumatoid arthritis is uncommon; when present it has been attributed to amyloid or secondary effects of drugs. Nevertheless, recent observations seem to indicate the existence of primary renal lesions associated with the disease. The purpose of this paper is to review the data suggesting that the kidney can be directly involved in Rheumatoid arthritis. The main points of interest are the occurrence of glomerulonephritis and/or amyloidosis, the presence of vasculitis and other arterial changes, the existence of chronic interstitial nephritis and papillary necrosis and lesions associated with gold and penicillamine therapy.  相似文献   
60.
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