全文获取类型
收费全文 | 879032篇 |
免费 | 93533篇 |
国内免费 | 564篇 |
出版年
2021年 | 7554篇 |
2018年 | 9876篇 |
2017年 | 9180篇 |
2016年 | 13072篇 |
2015年 | 17752篇 |
2014年 | 20229篇 |
2013年 | 28524篇 |
2012年 | 31926篇 |
2011年 | 31971篇 |
2010年 | 21559篇 |
2009年 | 19257篇 |
2008年 | 27484篇 |
2007年 | 27955篇 |
2006年 | 26453篇 |
2005年 | 25074篇 |
2004年 | 24837篇 |
2003年 | 23676篇 |
2002年 | 22700篇 |
2001年 | 39483篇 |
2000年 | 39686篇 |
1999年 | 31568篇 |
1998年 | 11297篇 |
1997年 | 11593篇 |
1996年 | 10937篇 |
1995年 | 10209篇 |
1994年 | 9830篇 |
1993年 | 9625篇 |
1992年 | 25290篇 |
1991年 | 24478篇 |
1990年 | 23854篇 |
1989年 | 23212篇 |
1988年 | 21549篇 |
1987年 | 20165篇 |
1986年 | 18675篇 |
1985年 | 18516篇 |
1984年 | 15415篇 |
1983年 | 12846篇 |
1982年 | 9786篇 |
1981年 | 8709篇 |
1980年 | 8168篇 |
1979年 | 13793篇 |
1978年 | 10751篇 |
1977年 | 9652篇 |
1976年 | 8724篇 |
1975年 | 9742篇 |
1974年 | 10400篇 |
1973年 | 10301篇 |
1972年 | 9217篇 |
1971年 | 8401篇 |
1970年 | 7221篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
E R Dalferes B Radhakrishnamurthy M S Crouch G S Berenson 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1975,148(3):918-924
The effect of obesity on the connective tissue composition of skin was investigated in mice with goldthioglucose (GTG)-induced obesity. Four months after GTG treatment, the obese animals were sacrificed. Acid mucopolysaccharides, glycoproteins, collagen, and elastin were analyzed in the skin and compared to the controls. Total MPS in the skin from obese animals decreased, reflected mostly in hyaluronic acid. Chondroitin showed an increase over controls. The content of soluble glycoproteins varied; total carbohydrate and sialic acid of the glycoprotein tended to increase with obesity. Collagen and elastin both tended to decrease with obesity. 相似文献
982.
983.
984.
985.
986.
987.
O M Grindel' 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1985,35(1):60-67
Power spectra and coherence function of EEG of various cortical areas of both hemispheres were analyzed in 9 patients with extremely protracted loss of consciousness. Five patients were in the state of posttraumatic apallic syndrome lasting for more than 4 years in one patient, and 4-9 months with successive lethal outcome in 4 patients. One patient for more than 2 years was in a state of areactivity to external signals. In 3 patients the process of recovery of consciousness and speech began in 1-2 months. At the apallic syndrome, only low-frequency EEG components were present in spectrograms, and the values of coherence function were sharply decreased. With recovering consciousness and speech, a gradual appearance of alpha-activity was observed as well as an increase of coherence values at the frequency of the alpha-rhythm. The recovery of intercentral EEG relations in the motor-verbal cortical area was shown to play a special role in further normalization of connections in the cerebral cortex. 相似文献
988.
989.
990.
R Varela-Calvino G Sgarbi L R Wedderburn C M Dayan J Tremble M Peakman 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(6):3513-3520
Numerous clinical and epidemiological studies link enteroviruses such as the Coxsackie virus group with the autoimmune disease type 1 diabetes mellitus (DM). In addition, there are reports that patients with type 1 DM are characterized by skewing of TCR Vbeta chain selection among peripheral blood and intraislet T lymphocytes. To examine these issues, we analyzed TCR Vbeta chain-specific up-regulation of the early T cell activation marker, CD69, on CD4 T cells after incubation with Coxsackievirus B4 (CVB4) Ags. CD4 T cells bearing the Vbeta chains 2, 7, and 8 were the most frequently activated by CVB4. Up-regulation of CD69 by different TCR families was significantly more frequent in new onset type 1 DM patients (p = 0.04), 100% of whom (n = 8) showed activation of CD4 T cells bearing Vbeta8, compared with 50% of control subjects (n = 8; p = 0.04). T cell proliferation after incubation with CVB4 Ags required live, nonfixed APCs, suggesting that the selective expansion of CD4 T cells with particular Vbeta chains resulted from conventional antigen processing and presentation rather than superantigen activity. Heteroduplex analysis of TCR Vbeta chain usage after CVB4 stimulation indicated a relatively polyclonal, rather than oligo- or monoclonal response to viral Ags. These results provide evidence that new-onset patients with type 1 DM and healthy controls are primed against CVB4, and that CD4 T cell responses to the virus have a selective TCR Vbeta chain usage which is driven by viral Ags rather than a superantigen. 相似文献