全文获取类型
收费全文 | 1911篇 |
免费 | 133篇 |
国内免费 | 14篇 |
专业分类
儿科学 | 3篇 |
妇产科学 | 66篇 |
基础医学 | 618篇 |
口腔科学 | 89篇 |
临床医学 | 36篇 |
内科学 | 418篇 |
皮肤病学 | 33篇 |
神经病学 | 59篇 |
特种医学 | 23篇 |
外科学 | 178篇 |
综合类 | 109篇 |
预防医学 | 50篇 |
眼科学 | 11篇 |
药学 | 217篇 |
1篇 | |
中国医学 | 15篇 |
肿瘤学 | 132篇 |
出版年
2023年 | 27篇 |
2022年 | 42篇 |
2021年 | 93篇 |
2020年 | 50篇 |
2019年 | 49篇 |
2018年 | 50篇 |
2017年 | 43篇 |
2016年 | 55篇 |
2015年 | 89篇 |
2014年 | 102篇 |
2013年 | 181篇 |
2012年 | 113篇 |
2011年 | 125篇 |
2010年 | 122篇 |
2009年 | 82篇 |
2008年 | 106篇 |
2007年 | 74篇 |
2006年 | 68篇 |
2005年 | 69篇 |
2004年 | 53篇 |
2003年 | 47篇 |
2002年 | 30篇 |
2001年 | 26篇 |
2000年 | 26篇 |
1999年 | 33篇 |
1998年 | 27篇 |
1997年 | 19篇 |
1996年 | 20篇 |
1995年 | 32篇 |
1994年 | 19篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 15篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 23篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有2058条查询结果,搜索用时 15 毫秒
21.
N. V. Berezhkov 《Bulletin of experimental biology and medicine》1992,113(2):270-276
Department of Pathomorphology, A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR D. S. Sarkisov). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 2, pp. 203–208, February, 1992. 相似文献
22.
Juan Peng Yanchun Han Jun Fu Yuming Yang Binyao Li 《Macromolecular chemistry and physics.》2003,204(1):125-130
Ordered macroporous materials recently have attracted much attention. A method that utilizes the condensation of monodisperse water droplets on a polymer solution is proposed for the preparation of honeycomb microporous films. Our results show that it is a general method that can be used for patterning a wide range of polymers. The presence of water vapor and polymer is necessary for the formation of regular holes in films. The formation of hexagonal packing instead of other kinds of packing takes place because the hexagonal packing has the lowest free energy. The formation mechanisms of regular hole pattern and imperfections in the hexagonal packing are proposed.
23.
Fernández J. L. Goyanes V. Pereira S. López-Fernández C. Gosálvez J. 《Chromosome research》1994,2(1):29-35
Fluorescencein situ hybridization employing human alphoid, beta and classical satellite DNA probes was performed on 5-azacytidine treated and untreated chromosomes obtained from human lymphocytes. The individual used in this study presented a polymorphism of constitutive heterochromatin of chromosomes 1 and 9 as revealed byin situ digestion with the restriction endonucleaseAlul. Neither the alphoid nor the beta satellite DNA domains were susceptible to condensation-inhibition by 5-azacytidine. Only the classical satellite localized on chromosome 9 was affected. The constitutive heterochromatin size polymorphism was shown to depend mainly on variations of the classical satellite DNA domain. Therefore, condensation-inhibition, as a phenomenon which may modify the natural folding of the chromatin fibre, regionally affects human constitutive heterochromatin and seems to be dependent on the heterochromatic family. 相似文献
24.
The manner of packing of the terminal DNA loci into nucleosomes and higher order structures may strongly influence their functional
interactions. Besides the structural flexibility of telomeric DNA sequences, conserved features of their chromatin including
short nucleosome phasing (157 bp) and nucleosome sliding have been described previously. To gain a complementary knowledge
of subtelomeres, we have analysed the chromatin structure of two subtelomeric tandem repeats from the plant Silene latifolia: X43.1 and 15Ssp. X43.1 shows two distinct nucleosome periodicities – 157 and 188 bp. Preferred positions of its two nucleosomes
have been mapped at both low and high resolution and the experimental results correspond to computer-predicted positions.
15Ssp is a newly-discovered sequence showing a telomere-associated position by PCR and a subtelomeric location by pulsed-field
gel electrophoresis and fluorescence in situ hybridisation. Its 159 bp sequence unit shows a tandem arrangement and the presence of micrococcal nuclease-hypersensitive
sites when either naked DNA or chromatin is digested. Use of a chemical nuclease results in a regular nucleosome ladder of
157 bp periodicity. Moreover, 15Ssp mononucleosomes show instability and absence of specific positioning, features typical
for telomeric chromatin.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
25.
26.
27.
Antibodies specific for dsDNA appear to have different genetic origins and pathogenic consequences, compared with histone/dsDNA-specific antibodies, in a recently described murine model. The purpose of this study was to examine if this is also true in human lupus. Sera from 40 SLE families (comprising 40 probands and 153 first-degree relatives), and 45 normal adult controls were assayed for the levels of anti-dsDNA, anti-H1/dsDNA, anti-H2A/H2B/dsDNA, and anti-H3/H4/dsDNA autoantibodies by ELISA. Both the probands and the first-degree relatives exhibited significantly increased levels of antinuclear antibodies (ANA) targeting the different subnucleosomal epitopes. Importantly, probands with anti-dsDNA antibodies had a significantly higher incidence of renal disease compared with those with just anti-H2A/H2B/dsDNA antibodies, in resonance with murine studies. The frequency of anti-dsDNA and anti-H2A/H2B/DNA ANA among the first-degree relatives was 11.8% and 18.3%, respectively. Surprisingly, whereas probands with anti-dsDNA ANA had families with several seropositive members, first-degree relatives of patients with anti-H2A/H2B/DNA ANA (but not anti-dsDNA ANA) were uniformly ANA-free. These findings suggest that anti-dsDNA ANA in lupus may not only have worse disease associations, they may also have very different genetic origins, compared with anti-H2A/H2B/DNA (or anti-nucleosome) ANA. 相似文献
28.
29.
Induction of chromosome aberrations and mitotic arrest by cytomegalovirus in human cells 总被引:6,自引:0,他引:6
S AbuBakar W W Au M S Legator T Albrecht 《Environmental and molecular mutagenesis》1988,12(4):409-420
Human cytomegalovirus (CMV) is potentially an effective but often overlooked genotoxic agent in humans. We report here evidence that indicates that infection by CMV can induce chromosome alterations and mitotic inhibition. The frequency of chromosome aberrations induced was dependent on the input multiplicity of infection (m.o.i.) for human lung fibroblasts (LU), but not for human peripheral blood lymphocytes (PBLs) when both cell types were infected at the GO phase of the cell cycle. The aberrations induced by CMV were mostly chromatid breaks and chromosome pulverizations that resembled prematurely condensed S-phase chromatin. Pulverized chromosomes were not observed in LU cells infected with virus stocks that had been rendered nonlytic by UV-irradiation at 24,000 ergs/mm2 or from infection of human lymphocytes. In LU cells infected with UV-irradiated CMV, the frequency of aberrations induced was inversely dependent on the extent of the exposure of the CMV stock to the UV-light. In permissive CMV infection of proliferating LU cells at 24 hr after subculture, a high percentage (greater than 40%) of the metaphase cells were arrested at their first metaphase and displayed severely condensed chromosomes when harvested 48 hr later. A significant increase (p less than 0.05) in the chromosome aberration frequency was also observed. Our study shows that CMV infection is genotoxic to host cells. The types and extent of damage are dependent on the viral genome expression and on the cell cycle stage of the cells at the time of infection. The possible mechanisms for induction of chromosome damage by CMV are discussed. 相似文献
30.