全文获取类型
收费全文 | 272篇 |
免费 | 10篇 |
国内免费 | 1篇 |
学科分类
生物科学 | 283篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 31篇 |
2012年 | 13篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 13篇 |
2007年 | 14篇 |
2006年 | 18篇 |
2005年 | 13篇 |
2004年 | 11篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有283条查询结果,搜索用时 218 毫秒
81.
Membranous glomerulonephritis development with Th2-type immune deviations in MRL/lpr mice deficient for IL-27 receptor (WSX-1) 总被引:5,自引:0,他引:5
Shimizu S Sugiyama N Masutani K Sadanaga A Miyazaki Y Inoue Y Akahoshi M Katafuchi R Hirakata H Harada M Hamano S Nakashima H Yoshida H 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(11):7185-7192
MRL/lpr mice develop spontaneous glomerulonephritis that is essentially identical with diffuse proliferative glomerulonephritis (World Health Organization class IV) in human lupus nephritis. Lupus nephritis is one of the most serious complications of systemic lupus erythematosus. Diffuse proliferative glomerulonephritis is associated with autoimmune responses dominated by Th1 cells producing high levels of IFN-gamma. The initial mounting of Th1 responses depends on the function of the WSX-1 gene, which encodes a subunit of the IL-27R with homology to IL-12R. In mice deficient for the WSX-1 gene, proper Th1 differentiation was impaired and abnormal Th2 skewing was observed during infection with some intracellular pathogens. Disruption of the WSX-1 gene dramatically changed the pathophysiology of glomerulonephritis developing in MRL/lpr mice. WSX-1-/- MRL/lpr mice developed disease resembling human membranous glomerulonephritis (World Health Organization class V) with a predominance of IgG1 in glomerular deposits, accompanied by increased IgG1 and IgE in the sera. T cells in WSX-1-/- MRL/lpr mice displayed significantly reduced IFN-gamma production along with elevated IL-4 expression. Loss of WSX-1 thus favors Th2-type autoimmune responses, suggesting that the Th1/Th2 balance may be a pivotal determinant of human lupus nephritis development. 相似文献
82.
Yoshimura K Aoki H Ikeda Y Fujii K Akiyama N Furutani A Hoshii Y Tanaka N Ricci R Ishihara T Esato K Hamano K Matsuzaki M 《Nature medicine》2005,11(12):1330-1338
Abdominal aortic aneurysm (AAA) is a common disease among elderly people that, when surgical treatment is inapplicable, results in progressive expansion and rupture of the aorta with high mortality. Although nonsurgical treatment for AAA is much awaited, few options are available because its molecular pathogenesis remains elusive. Here, we identify JNK as a proximal signaling molecule in the pathogenesis of AAA. Human AAA tissue showed a high level of phosphorylated JNK. We show that JNK programs a gene expression pattern in different cell types that cooperatively enhances the degradation of the extracellular matrix while suppressing biosynthetic enzymes of the extracellular matrix. Selective inhibition of JNK in vivo not only prevented the development of AAA but also caused regression of established AAA in two mouse models. Thus, JNK promotes abnormal extracellular matrix metabolism in the tissue of AAA and may represent a therapeutic target. 相似文献
83.
Hydrophobic bile acids induce apoptosis in both colon cancer cells and hepatocytes. The mechanism by which colon cancer cells respond to bile acids is thought to be different from that of hepatocytes. Therefore, we investigated the characteristics of apoptosis in colon cancer cell line HCT116. Hydrophobic bile acids, i.e., deoxycholic acid (DCA), and chenodeoxycholic acid, induced apoptosis in HCT116 cells. Apoptotic indications were detectable at as early as 30 min and the extent increased in time- and concentration-dependent manners. SDS and a hydrophilic bile acid, cholic acid, did not induce apoptosis even at cytotoxic concentrations. Pretreatment with cycloheximide failed to inhibit apoptosis, suggesting that protein synthesis is not involved in the apoptotic response. Release of cytochrome c from mitochondria and activation of caspase-9 were detectable after 5 and 10 min, respectively, whereas remarkable activation of Bid was not detected. Ursodeoxycholic acid (UDCA) protected HCT116 cells from DCA-induced apoptosis but a preincubation period of > or =5 h was required. Nevertheless, UDCA did not inhibit cytochrome c release from mitochondria. Our results indicate that hydrophobic bile acids induce apoptosis in HCT116 cells by releasing cytochrome c from mitochondria via an undefined but specific mechanism, and that UDCA protects HCT116 cells by acting downstream of cytochrome c release. 相似文献
84.
Higo H Miura S Horio M Mimori T Hamano S Agatsuma T Yanagi T Cruz-Reyes A Uyema N Rojas de Arias A Matta V Akahane H Hirayama K Takeuchi T Tada I Himeno K 《Parasitology international》2004,53(4):337-344
Isozyme analysis with 18 enzyme loci was conducted on 146 isolates of Trypanosoma cruzi from Mexico, Guatemala, Colombia, Ecuador, Peru, Brazil, Bolivia, Paraguay and Chile. Forty-four different MLGs (groups of isolates with identical multilocus genotypes) were identified and a phylogeny was constructed. The phylogenetic tree consisted of two main groups (T. cruzi I, T. cruzi II), and the latter was further divided into two subgroups (T. cruzi IIa, T. cruzi IIb–e). Evidence of hybridization between different MLGs of T. cruzi II was found, which means that genetic exchanges seem to have occurred in South American T. cruzi. On the other hand, the persistence of characteristic T. cruzi I and T. cruzi II isozyme patterns in single small villages in Bolivia and Guatemala suggested that genetic exchange is very rare between major lineages. A significant difference in genetic diversity was shown between T. cruzi I and T. cruzi II from several indices of population genetics. Two possibilities could explain this genetic variation in the population: differences in evolutionary history and/or different tendencies to exchange genetic material. Broad-scale geographic distributions of T. cruzi I and T. cruzi IIb–e were different; T. cruzi I occurred in Central America and south to Bolivia and Brazil, while T. cruzi IIb–e occurred in the central and southern areas of South America, overlapping with T. cruzi I in Brazil and Bolivia. 相似文献
85.
86.
Nagaoka MH Yamazaki T Maitani T 《Biochemical and biophysical research communications》2002,296(5):1207-1214
Vanadium (V) is an essential metal for mammals and has different valence states. In blood, V is bound to serum transferrin (Tf), a glycoprotein which has two metal-binding sites, and carbonate is generally required for the binding. In this study, the binding patterns of V(III), V(IV), and V(V) to human serum Tf (hTf) were analyzed using an HPLC system equipped with an anion-exchange column and directly connected to a high-resolution inductively coupled plasma-mass spectrometer for metal detection (51V). In affinity to hTf, the three ions were ranked V(III)>V(IV)>V(V) in the presence of bicarbonate and V(III) reverse congruent V(IV)>V(V) in the absence. Intermediates in the "open forms" binding to the respective sites were detected at the initial stage. V(IV) and V(V) were bound to the N-lobe site in the "closed form" and "open form," respectively. In the absence of bicarbonate, V ions with respective valence states were bound to hTf in the "open form." In terms of binding to hTf, tri-valent V was most favorable in the presence of bicarbonate. 相似文献
87.
Shiau-Ta Chung Mitsutoshi Hamano Kȏ Aida Teijiro Uemura 《Bioscience, biotechnology, and biochemistry》2013,77(10):1287-1291
Water insoluble ATP deaminase was prepared by binding native ATP deaminase to DEAE-cellulose and several enzymatic properties of bound ATP deaminase were compared with those of free deaminase. The optimum pH of the former was 3.0 and shifted toward acid side by about 2 pH units compared with that of the latter. The activity of bound deaminase to ATP corresponded to about one fourth of free deaminase at pH 3.0. The possibility of continuous preparation of IMP from AMP by use of bound deaminase was suggested. 相似文献
88.
Hisateru Mitsuda Kyoden Yasumoto Kimikazu Iwami 《Bioscience, biotechnology, and biochemistry》2013,77(4):453-458
Volatiles stripped from rice bran are analyzed by gas chromatography and thin-layer chromatography either directly or after converted into 2, 4-DNPH’s or 3, 5-DNB’s. Most of prominent peaks revealed by a direct gas chromatography of the volatiles condensates behave as alcohols against classification reagents and are identified as methanol, ethanol, n-propanol, sec-butanol, isobutanol, n-butanol, isopentanol, n-pentanol and n-hexanol, respectively. Ethanol and methanol, being major components in the condensates are also detected by thin-layer chromatography of their 3, 5-DNB’s. Carbonyls identified by a flash exchange gas chromatography of 2, 4-DNPH’s of the volatiles are ethanal, propanal, isobutanal, acetone, n-butanal, isopentanal, n-pentanal and n-hexanal. Thin-layer chromatography of 2, 4-DNPH’s reveals presence of ethanal, acetone, isopentanal or/and isobutanal and n-hexanal in the volatiles. The experimental data have been integrated to furnish a basis for extensive comparison with other rice products and by-products. 相似文献
89.
Chihiro Tanigawa Yoshito Fujii Masashi Miura Samson Muuo Nzou Anne Wanjiru Mwangi Sachiyo Nagi Shinjiro Hamano Sammy M. Njenga Evaristus Chibunna Mbanefo Kenji Hirayama Matilu Mwau Satoshi Kaneko 《PLoS neglected tropical diseases》2015,9(8)