全文获取类型
收费全文 | 439篇 |
免费 | 33篇 |
国内免费 | 29篇 |
出版年
2023年 | 3篇 |
2022年 | 12篇 |
2021年 | 16篇 |
2020年 | 13篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 12篇 |
2016年 | 13篇 |
2015年 | 19篇 |
2014年 | 31篇 |
2013年 | 35篇 |
2012年 | 30篇 |
2011年 | 32篇 |
2010年 | 28篇 |
2009年 | 12篇 |
2008年 | 32篇 |
2007年 | 26篇 |
2006年 | 24篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1960年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有501条查询结果,搜索用时 31 毫秒
111.
112.
113.
Spores and prothallia of the fern Anemia phyllitidis L. Sw. contain a protein which in its physicochemical properties corresponds largely to calmodulin. It shows immunoreactivity with a calmodulin antiserum and activates bovine brain phosphodiesterase. Its content increases during the early processes of light-induced spore germination, indicating that the Ca2+-dependence of these processes may be mediated by this protein.Abbreviations EGTA
ethylene, glycol-bis(-aminoethyl ether)-N,N,N,N-tetraacetic acid
- RIA
radioimmunoassay 相似文献
114.
115.
116.
117.
Anginex, a novel artificial cytokine-like peptide (βpep-25), is designed by using basic folding principles and incorporating short sequences from the β-sheet domains of anti-angiogenic agents, including platelet factor-4 (PF4), interleukin-8 (IL-8), and bactericidal-permeability increasing protein 1 (BP1). Anginex can specially block the adhesion and migration of the angiogenically activated endothelial cells (ECs), leading to apoptosis and ultimately to the inhibition of angiogenesis and tumor growth. In vitro and in vivo studies have proved its inhibitory effects on the formation of new blood vessels and tumor growth even though the mechanism is not clear. The inhibitory effects of anginex can be enhanced when it is applied in combination with other therapies, such as chemotherapy, radiotherapy and other anti-angiogenic agents. The limitations of anginex, including poor stability, short half life, complicated synthesis and low purity, have been conquered by modifying its structure or designing novel compound anginex and recombinant anginex, which makes possible the clinical application of anginex. Here, we summarize the basic and preclinical trials of anginex and discuss the prospects of anginex in clinical application. We come to the conclusion that anginex and compound or recombinant anginex can be used as effective anti-angiogenic agents. 相似文献
118.
Tian Yan Liu Ying Li Xiao Xiao Liu Xin Hua Sui Xiao Xia Zhang En Tao Wang Wen Xin Chen Wen Feng Chen Joanna Puławska 《Systematic and applied microbiology》2012,35(7):415-420
Three bacterial isolates (CCBAU 101002T, CCBAU 101000 and CCBAU 101001) originating from root nodules of the herbaceous legume Kummerowia stipulacea grown in the campus lawn of China Agricultural University were characterized with a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence analysis showed that the isolates shared 99.85–99.92% sequence similarities and had the highest similarities to the type strains of Rhizobium mesoamericanum (99.31%), R. endophyticum (98.54%), R. tibeticum (98.38%) and R. grahamii (98.23%). Sequence similarity of four concatenated housekeeping genes (atpD, glnII, recA and rpoB) between CCBAU 101002T and its closest neighbor (R. grahamii) was 92.05%. DNA–DNA hybridization values between strain CCBAU 101002T and the four type strains of the most closely related Rhizobium species were less than 28.4 ± 0.8%. The G + C mol% of the genomic DNA for strain CCBAU 101002T was 58.5% (Tm). The major respiratory quinone was ubiquinone (Q-10). Summed feature 8 (18:1ω7cis/18:1ω6cis) and 16:0 were the predominant fatty acids. Strain CCBAU 101002T contained phosphatidylcholine and phosphatidylethanolamine as major polar lipids, and phosphatidylglycerol and cardiolipin as minor ones. No glycolipid was detected. Unlike other strains, this novel species could utilize dulcite or sodium pyruvate as sole carbon sources and it was resistant to 2% (w/v) NaCl. On the basis of the polyphasic study, a new species Rhizobium cauense sp. nov. is proposed, with CCBAU 101002T (=LMG 26832T = HAMBI 3288T) as the type strain. 相似文献
119.
Loss of the maternal imprint in Dnmt3Lmat-/- mice leads to a differentiation defect in the extraembryonic tissue 总被引:3,自引:0,他引:3
Arima T Hata K Tanaka S Kusumi M Li E Kato K Shiota K Sasaki H Wake N 《Developmental biology》2006,297(2):361-373
DNA methylation of the genome is essential for mammalian development and plays crucial roles in a variety of biological processes including genomic imprinting. Although the DNA methyltransferase 3-like (Dnmt3L) protein lacks DNA methylase activity, it is thought to establish the maternal imprint in combination with the functional DNA methyltransferases. Oogenesis apparently proceeds normally in female mice homozygous for a targeted deletion of Dnmt3L, but their heterozygous offspring (Dnmt3L(mat-/-)) die before midgestation due to an imprinting defect. In this study, we show that Dnmt3L is required for the establishment of maternal methylation imprints both in the embryos and the placentae and that the placentae of these embryos develop abnormally. There is a defect in the formation of the labyrinth, reduced formation of the spongiotrophoblast layer, excess trophoblast giant cells and insufficient attachment between the chorion layer and the ectoplacental cone. In addition, we demonstrate arrest of proliferation of the extraembryonic tissue without apoptosis in vivo and a disturbance of the cell fate of Dnmt3L(mat-/-) trophoblastic stem cells in vitro. Furthermore, we report that DNA methylation during oogenesis is essential for the establishment of imprinting Mash2. These findings provide evidence that not only is DNA methylation required for the appropriate maternal imprint in the placenta but that the appropriate imprint is absolutely required for vertebrate placentation. 相似文献
120.
Structure and function of glucose-6-phosphate dehydrogenase-deficient variants in Chinese population 总被引:9,自引:0,他引:9
Jiang W Yu G Liu P Geng Q Chen L Lin Q Ren X Ye W He Y Guo Y Duan S Wen J Li H Qi Y Jiang C Zheng Y Liu C Si E Zhang Q Tian Q Du C 《Human genetics》2006,119(5):463-478
A systematic study on the structure and function of Glucose-6-phosphate dehydrogenase (G6PD) variations was carried out in China. A total of 155,879 participants were screened for G6PD deficiency by the G6PD/6PGD ratio method and 6,683 cases have been found. The prevalence of G6PD deficiency ranged from 0 to 17.4%. With informed consent, 1,004 cases from 11 ethnic-based groups were subjected to molecular analysis. Our results showed the followings: (1) The G6PD variants are consistent across traditional ethnic boundaries, but vary in frequencies across ethnic-based groups in Chinese population, (2) The G6PD variants in Chinese population are different from those in African, European, and Indian populations, (3) A novel G6PD-deficiency mutation, 274C→T, has been found, and (4) Denaturing high performance liquid chromatography is of great advantage to detecting G6PD-deficient mutations for diagnosis and genetic counseling. Moreover, functional analysis of the human G6PD variants showed the following: (1) The charge property, polarity, pK-radical and side-chain radical of the substituting amino acid have an effect on G6PD activity, (2) The G6PDArg459 and Arg463 play important roles in anchoring NADP+ to the catalytic domain to maintain the enzymatic activity, and (3) The sequence from codon 459 to the carboxyl terminal is essential for the enzymatic function. 相似文献