全文获取类型
收费全文 | 1237篇 |
免费 | 179篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 62篇 |
妇产科学 | 8篇 |
基础医学 | 232篇 |
口腔科学 | 13篇 |
临床医学 | 190篇 |
内科学 | 257篇 |
皮肤病学 | 19篇 |
神经病学 | 68篇 |
特种医学 | 138篇 |
外科学 | 111篇 |
综合类 | 49篇 |
预防医学 | 151篇 |
眼科学 | 18篇 |
药学 | 101篇 |
中国医学 | 1篇 |
肿瘤学 | 56篇 |
出版年
2021年 | 17篇 |
2018年 | 15篇 |
2017年 | 12篇 |
2016年 | 13篇 |
2015年 | 26篇 |
2014年 | 23篇 |
2013年 | 35篇 |
2012年 | 46篇 |
2011年 | 44篇 |
2010年 | 41篇 |
2009年 | 37篇 |
2008年 | 32篇 |
2007年 | 76篇 |
2006年 | 50篇 |
2005年 | 48篇 |
2004年 | 24篇 |
2003年 | 21篇 |
2002年 | 32篇 |
2001年 | 25篇 |
2000年 | 24篇 |
1999年 | 46篇 |
1998年 | 35篇 |
1997年 | 46篇 |
1996年 | 30篇 |
1995年 | 26篇 |
1994年 | 17篇 |
1993年 | 32篇 |
1992年 | 22篇 |
1991年 | 30篇 |
1990年 | 39篇 |
1989年 | 49篇 |
1988年 | 35篇 |
1987年 | 46篇 |
1986年 | 28篇 |
1985年 | 17篇 |
1984年 | 26篇 |
1983年 | 22篇 |
1982年 | 12篇 |
1981年 | 23篇 |
1980年 | 19篇 |
1979年 | 17篇 |
1978年 | 12篇 |
1977年 | 14篇 |
1975年 | 12篇 |
1973年 | 14篇 |
1972年 | 13篇 |
1971年 | 17篇 |
1970年 | 11篇 |
1969年 | 17篇 |
1967年 | 14篇 |
排序方式: 共有1477条查询结果,搜索用时 781 毫秒
11.
Endogenous glutathione levels modulate both constitutive and UVA radiation/hydrogen peroxide inducible expression of the human heme oxygenase gene. 总被引:10,自引:1,他引:9
Induction of the expression of the mammalian heme oxygenase gene appears to be a general response to oxidant stress. In view of the role of glutathione in protecting cells against solar UVA radiation and other forms of oxidant stress, we have investigated the relationship between intracellular glutathione levels and the inducibility of the human heme oxygenase gene after treatment of populations of cultured skin fibroblasts with either UVA radiation or hydrogen peroxide. We observe a clear relationship between cellular glutathione status and both the constitutive and oxidant-inducible accumulation of heme oxygenase mRNA. Glutathione depletion may lead to enhanced gene expression either as a result of the potentiated accumulation of active oxygen intermediates or as a result of the direct influence of glutathione on a critical target involved in signal transduction. 相似文献
12.
13.
Background
There is currently an unprecedented expressed need and demand for estimates of maternal mortality in developing countries. This has been stimulated in part by the creation of a Millennium Development Goal that will be judged partly on the basis of reductions in maternal mortality by 2015. 相似文献14.
15.
Use of polymerase chain reaction for diagnosis of picornavirus infection in subjects with and without respiratory symptoms. 总被引:10,自引:13,他引:10
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
S L Johnston G Sanderson P K Pattemore S Smith P G Bardin C B Bruce P R Lambden D A Tyrrell S T Holgate 《Journal of clinical microbiology》1993,31(1):111-117
Rhinoviruses and enteroviruses are the major members of the picornavirus genus that cause human disease. We compared the polymerase chain reaction and viral culture for the identification of picornaviruses in nasal aspirates from children during episodes of respiratory symptoms and when asymptomatic and from asymptomatic adults. One hundred eight children, aged 9 to 11 years, completed a year-long study. Within 24 to 48 h of a report of respiratory symptoms, a nasal aspirate was taken in the home. Nasal aspirates were also taken from 65 of the children and from 33 normal adults when they had been free of respiratory symptoms for at least 2 weeks. Picornaviruses were isolated by culture for three passages in Ohio HeLa cells in rolling tubes at 33 degrees C and pH 7.0. For the polymerase chain reaction, duplicate 50-microliters samples were amplified with conserved primers from the 5' noncoding region. Picornaviruses generated approximately 380-bp bands in agarose gel electrophoresis; the specificity of these bands was confirmed by filter hybridization with a conserved internal probe. Picornaviruses were isolated by culture in 47 (46 rhinoviruses) of 292 symptomatic episodes (16%), whereas the polymerase chain reaction identified picornavirus genomic material in 146 episodes (50%), including all but one of the culture-positive episodes. As for asymptomatic samples, eight (12%) children and two (4%) adults were positive by the polymerase chain reaction, whereas only one child's specimen was positive by culture. This polymerase chain reaction assay represents a clear advance in the identification of picornavirus infection, with a detection rate threefold greater than the virus culture method. 相似文献
16.
17.
Paramyxovirus membrane protein augments the antibody response to actin in mice. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The production of anti-actin antibodies has been studied in mice. Not one of 10 mice immunized with native actin produced anti-actin antibodies, whereas seven out of 10 mice immunized with actin mixed with paramyxovirus membrane (M) protein produced a high titre of antibodies to actin. The enhancement of anti-actin antibody production by M protein is specific to actin since antibodies to protein purified derivatives (PPD) or gelatin were not enhanced by M protein. The enhanced anti-actin antibodies depended upon the interaction of actin and M protein since injection of M protein and actin in separate sites failed to produce anti-actin antibodies. Five Balb/c nude mice immunized with actin and M protein failed to produce anti-actin antibodies suggesting that cell-mediated immune response is also required for this response. 相似文献
18.
19.
The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry 总被引:8,自引:1,他引:8
Nistico L; Buzzetti R; Pritchard LE; Van der Auwera B; Giovannini C; Bosi E; Larrad MT; Rios MS; Chow CC; Cockram CS; Jacobs K; Mijovic C; Bain SC; Barnett AH; Vandewalle CL; Schuit F; Gorus FK; Tosi R; Pozzilli P; Todd JA 《Human molecular genetics》1996,5(7):1075-1080
Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus
is determined by a combination of environmental and genetic factors, which
include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin
gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2
cannot explain the clustering of type 1 diabetes in families, and a role
for other genes is inferred. In the present report we describe linkage and
association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte
associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong
candidate gene for T cell- mediated autoimmune disease because it encodes a
T cell receptor that mediates T cell apoptosis and is a vital negative
regulator of T cell activation. In addition, we provide supporting evidence
that CTLA-4 is associated with susceptibility to Graves' disease, another
organ- specific autoimmune disease.
相似文献
20.