全文获取类型
收费全文 | 1168篇 |
免费 | 75篇 |
出版年
2022年 | 10篇 |
2021年 | 6篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 16篇 |
2016年 | 23篇 |
2015年 | 38篇 |
2014年 | 49篇 |
2013年 | 59篇 |
2012年 | 65篇 |
2011年 | 57篇 |
2010年 | 44篇 |
2009年 | 24篇 |
2008年 | 61篇 |
2007年 | 65篇 |
2006年 | 46篇 |
2005年 | 59篇 |
2004年 | 57篇 |
2003年 | 70篇 |
2002年 | 61篇 |
2001年 | 50篇 |
2000年 | 40篇 |
1999年 | 31篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 6篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 15篇 |
1991年 | 20篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 13篇 |
1987年 | 17篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1973年 | 4篇 |
1970年 | 4篇 |
1969年 | 4篇 |
排序方式: 共有1243条查询结果,搜索用时 46 毫秒
61.
NF-kappaB promotes breast cancer cell migration and metastasis by inducing the expression of the chemokine receptor CXCR4 总被引:34,自引:0,他引:34
Helbig G Christopherson KW Bhat-Nakshatri P Kumar S Kishimoto H Miller KD Broxmeyer HE Nakshatri H 《The Journal of biological chemistry》2003,278(24):21631-21638
62.
63.
64.
65.
Tahara S Ohkawa K Takayama T Ogawa Y 《Bioscience, biotechnology, and biochemistry》2001,65(8):1755-1760
A bioassay-guided survey of spinach leaf constituents resulted in 5,4'-dihydroxy-3,3'-dimethoxy-6,7-methylenedioxyflavone being identified as the third naturally-occurring attractant in the host plant toward the zoospores of its pathogen, Aphanomyces cochlioides. The isolate showed attracting activity around Chromosorb W AW particles (60-80 mesh) coated with a 10(-5) M solution in a zoospore suspension. However, this activity was 1/100-1/1000 less than that of cochliophilin A, an attractant in the roots of spinach. Bioassays with the present isolate and related compounds revealed that 5,3',4'-trihydroxy-3-methoxy-6,7-methylenedioxyflavone did not possess attractant activity, but rather weak antagonistic activity toward the former two attractants from spinach. 相似文献
66.
67.
Causal relationship between the loss of RUNX3 expression and gastric cancer 总被引:137,自引:0,他引:137
Li QL Ito K Sakakura C Fukamachi H Inoue Ki Chi XZ Lee KY Nomura S Lee CW Han SB Kim HM Kim WJ Yamamoto H Yamashita N Yano T Ikeda T Itohara S Inazawa J Abe T Hagiwara A Yamagishi H Ooe A Kaneda A Sugimura T Ushijima T Bae SC Ito Y 《Cell》2002,109(1):113-124
Runx3/Pebp2alphaC null mouse gastric mucosa exhibits hyperplasias due to stimulated proliferation and suppressed apoptosis in epithelial cells, and the cells are resistant to growth-inhibitory and apoptosis-inducing action of TGF-beta, indicating that Runx3 is a major growth regulator of gastric epithelial cells. Between 45% and 60% of human gastric cancer cells do not significantly express RUNX3 due to hemizygous deletion and hypermethylation of the RUNX3 promoter region. Tumorigenicity of human gastric cancer cell lines in nude mice was inversely related to their level of RUNX3 expression, and a mutation (R122C) occurring within the conserved Runt domain abolished the tumor-suppressive effect of RUNX3, suggesting that a lack of RUNX3 function is causally related to the genesis and progression of human gastric cancer. 相似文献
68.
Shuichiro Ito Tomoko Takayama Hiroyuki Hanzawa Kimihisa Ichikawa Jun Ohsumi Nobufusa Serizawa Tadashi Hata Hideyuki Haruyama 《Journal of biochemistry》2002,131(1):137-143
Binding of Fas ligand to Fas induces apoptosis. The Fas-Fas ligand system plays important roles in many biological processes, including the elimination of autoreactive lymphoid cells. The mouse anti-human Fas monoclonal antibody HFE7A (m-HFE7A), which induces apoptosis, has been humanized based on a structure predicted by homology modeling. A version of humanized HFE7A is currently under development for the treatment of autoimmune diseases such as rheumatoid arthritis. For a deeper understanding of the protein engineering aspect of antibody humanization, for which information on the three-dimensional structure is essential, we determined the crystal structure of the m-HFE7A antigen-binding fragment (Fab) by X-ray crystallography at 2.5 A resolution. The main-chain conformation of the five loops in the six complementarity-determining regions (CDRs) was correctly predicted with root-mean-square deviations of 0.30-1.04 A based on a comparison of the crystal structure with the predicted structure. The CDR-H3 conformation of the crystal structure, which was not classified as one of the canonical structures, was completely different from that of the predicted structure but adopted the conformation which followed the "H3-rules." The results of charge distribution analysis of the antigen-binding site suggest that electrostatic interactions may be important for its binding to Fas. 相似文献
69.
In Silene vulgaris (M.) G. cell culture three growth phases were distinguished, namely, a lag phase, an exponential phase and a stationary phase. Pectin termed silenan and an acidic arabinogalactan were isolated as cell wall polysaccharides of S. vulgaris callus at the different growth phases during culture. Production of silenan as the galacturonan (or rhamnogalacturonan) core was observed at the beginning of the exponential phase and at the stationary phase of the callus growth. Arabinogalactan, containing the galacturonic acid residues, is formed at the exponential phase followed by attachment to the core of silenan in the middle of the exponential phase. The arabinogalactan constituent of silenan appeared to be destroyed gradually at the stationary growth phase. The monosaccharide compositions of silenan and arabinogalactan were determined at various phases of the callus growth. Silenan was found to be formed in maximum amounts at the exponential phase of the cell growth. Insignificant alterations of the yields of acidic arabinogalactan were found during culture while total productivity per litre of medium and rate of production per day of arabinogalactan were found to be maximal at the exponential phase of growth. 相似文献
70.
Watanabe N Takayama S Yoshida S Isogai A Che FS 《Bioscience, biotechnology, and biochemistry》2002,66(9):1799-1805
Tobacco YZI-IS cells exhibit a 150-fold greater resistance to the protoporphyrinogen oxidase (Protox)-inhibiting compound, S23142, from wild-type tobacco cells. To investigate the mechanism for this S23142 resistance, the protein level, enzymatic activity, and sensitivity to S23142 in two Protox isoenzymes (plastidal and mitochondrial forms) were examined. The level of mitochondrial Protox protein was greater, and its activity 5-times higher, in YZI-IS cells than in wild-type cells. Furthermore, the apparent IC50 value of S23142 was about 20 nM, which is 20-fold higher than that observed in wild-type cells. In contrast, no differences were found in the plastidal Protox protein level, activity or its inhibition by S23142 between YZI-1S and wild-type cells. A southern blot analysis revealed that the mitochondrial Protox gene had been significantly amplified in the YZI-1S cells. These results suggest that the S23142 resistance of YZI-1S cells was due to the overproduction of mitochondrial Protox by gene amplification. 相似文献