全文获取类型
收费全文 | 1589篇 |
免费 | 206篇 |
国内免费 | 12篇 |
出版年
2023年 | 6篇 |
2022年 | 11篇 |
2021年 | 21篇 |
2020年 | 16篇 |
2019年 | 29篇 |
2018年 | 33篇 |
2017年 | 29篇 |
2016年 | 47篇 |
2015年 | 67篇 |
2014年 | 85篇 |
2013年 | 106篇 |
2012年 | 126篇 |
2011年 | 86篇 |
2010年 | 71篇 |
2009年 | 67篇 |
2008年 | 85篇 |
2007年 | 73篇 |
2006年 | 81篇 |
2005年 | 55篇 |
2004年 | 64篇 |
2003年 | 58篇 |
2002年 | 65篇 |
2001年 | 46篇 |
2000年 | 35篇 |
1999年 | 40篇 |
1998年 | 19篇 |
1997年 | 19篇 |
1996年 | 16篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 19篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 16篇 |
1985年 | 10篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1980年 | 13篇 |
1979年 | 10篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1975年 | 22篇 |
1974年 | 13篇 |
1973年 | 18篇 |
1972年 | 9篇 |
排序方式: 共有1807条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
By studying the responses of nitric oxide in pulmonary fibrosis, the role of inducible nitric oxide synthase in diffuse pulmonary fibrosis as caused by lipopolysaccharide (LPS) treatment was investigated. When compared to rats treated with LPS only, the rats pretreated with 1400W (an iNOS-specific inhibitor) were found to exhibit a reduced level in: (i) NOx (nitrate/nitrite) production, (ii) collagen type I protein expression, (iv) soluble collagen production, and (iv) the loss of body weight and carotid artery PO2. In the pulmonary fibroblast culture, exogenous NO from LPS-stimulated secretion by macrophages or from a NO donor, such as DETA NONOate, was observed to induce the expression of TIMP-1, HSP47, TGF-beta1, and collagen type I as well as the phosphorylation of SMAD-2. After inhalation of NO for 24 h, an up-regulation of collagen type I protein was also noted to occur in rat pulmonary tissue. The results suggest that the NO signal pathway enhanced the expression of TGF-beta1, TIMP-1, and HSP47 in pulmonary fibroblasts, which collectively demonstrate that the NO signal pathway could activate the SMAD-signal cascade, by initiating a rapid increase in TGF-beta1, thereby increasing the expression of TIMP-1 and HSP47 in pulmonary fibroblasts, and play an important role in pulmonary fibrosis. 相似文献
996.
997.
Global expression analysis of nucleotide binding site-leucine rich repeat-encoding and related genes in Arabidopsis 总被引:1,自引:0,他引:1
Xiaoping Tan Blake C Meyers Alexander Kozik Marilyn AL West Michele Morgante Dina A St Clair Andrew F Bent Richard W Michelmore 《BMC plant biology》2007,7(1):56
Background
Nucleotide binding site-leucine rich repeat (NBS-LRR)-encoding genes comprise the largest class of plant disease resistance genes. The 149 NBS-LRR-encoding genes and the 58 related genes that do not encode LRRs represent approximately 0.8% of all ORFs so far annotated in Arabidopsis ecotype Col-0. Despite their prevalence in the genome and functional importance, there was little information regarding expression of these genes. 相似文献998.
Hsiao YY Pan YJ Hsu SH Huang YT Liu TH Lee CH Lee CH Liu PF Chang WC Wang YK Chien LF Pan RL 《Biochimica et biophysica acta》2007,1767(7):965-973
Plant vacuolar H+-translocating inorganic pyrophosphatase (V-PPase EC 3.6.1.1) utilizes inorganic pyrophosphate (PPi) as an energy source to generate a H+ gradient potential for the secondary transport of ions and metabolites across the vacuole membrane. In this study, functional roles of arginine residues in mung bean V-PPase were determined by site-directed mutagenesis. Alignment of amino-acid sequence of K+-dependent V-PPases from several organisms showed that 11 of all 15 arginine residues were highly conserved. Arginine residues were individually substituted by alanine residues to produce R-->A-substituted V-PPases, which were then heterologously expressed in yeast. The characteristics of mutant variants were subsequently scrutinized. As a result, most R-->A-substituted V-PPases exhibited similar enzymatic activities to the wild-type with exception that R242A, R523A, and R609A mutants markedly lost their abilities of PPi hydrolysis and associated H+-translocation. Moreover, mutation on these three arginines altered the optimal pH and significantly reduced K+-stimulation for enzymatic activities, implying a conformational change or a modification in enzymatic reaction upon substitution. In particular, R242A performed striking resistance to specific arginine-modifiers, 2,3-butanedione and phenylglyoxal, revealing that Arg242 is most likely the primary target residue for these two reagents. The mutation at Arg242 also removed F- inhibition that is presumably derived from the interfering in the formation of substrate complex Mg2+-PPi. Our results suggest accordingly that active pocket of V-PPase probably contains the essential Arg242 which is embedded in a more hydrophobic environment. 相似文献
999.
Seu-Mei Wang Tsorng-Harn Fong Shu-Yuan Hsu Chung-Liang Chien Jiahn-Chun Wu 《Journal of cellular biochemistry》1997,67(1):84-91
We have found that the antibody A2, a marker for the capsule of steroidogenic lipid droplets, reacts with an intermediate filament-associated protein, P200, in 3T3-L1 preadipocytes. Supporting evidence came from the colocalization pattern of P200 with vimentin in double label experiments. The association of P200 with vimentin was further confirmed by its copurification with vimentin after high salt extraction and colocalization of these two proteins in high salt-extracted and vinblastine-treated cells. In preadipocytes this protein was distributed on the vimentin filament network. At the early stage of adipose conversion, this protein was found to encircle nascent lipid droplets ranging from 0.1 to 0.2 μm, accompanied with a decreased distribution on the vimentin filament system. This infers a possible translocation of P200 from the vimentin filaments to the droplet surface. Meanwhile, the vimentin filaments remained in a normal distribution in the cytoplasm and were apparently not associated with the nascent droplet. The association of vimentin filaments to droplet surfaces became prominent in lipid droplets larger than 0.2 μm, forming a typical vimentin cage. Immunogold staining also confirmed the translocation of P200 immunoreactivity from the droplet surface to the vimentin cage. The relocation of P200 from the cytoplasmic vimentin filaments to the droplet surface prior to the formation of the vimentin cage, as well as the reorganization of this protein in the vimentin cage, suggests a stabilizing role in the lipid droplet formation and an inducing function of this protein in the formation of the vimentin cage. J. Cell. Biochem. 67:84–91, 1997. © 1997 Wiley-Liss, Inc. 相似文献
1000.