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921.
乙型肝炎病毒X基因及HBx蛋白的研究进展 总被引:6,自引:0,他引:6
我国是乙型肝炎高发区,乙型肝炎病毒(HBV)X基因及其编码的多功能蛋白HBx是乙型肝炎病毒基因转录所必需的作用因子,在乙肝的致病过程中起到重要作用。HBx可直接或间接改变肝脏结构细胞的结构和功能,引发肝脏细胞的凋亡;具有广泛的非特异性反式激活作用,反式激活细胞内的某些癌基因或病毒基因,与乙型肝炎和肝细胞癌的发生关系十分密切。本文从多方面综述了X基因及HBx蛋白目前的研究进展,展现了X基因功能的多样性。 相似文献
922.
目的:探讨丙型肝炎病毒(HCV)不同基因型C蛋白在HepG2细胞中的基因表达。方法:分别构建能在HepG2细胞表达HCV-1b、HCV-2a和HCV-4d等3种基因型C蛋白的重组体,将Affymetrix公司人基因芯片HG-U133A和HG-U133B用于本研究。结果:3种C蛋白均可引起不同基因上调和下调改变。3种C蛋白表达如两两相比,有若干相同基因表达改变;如三者相比,有PPM1A、TNNI2、ZNF236、FSCN1基因表达出现相同改变。结论:HCV不同基因型C蛋白所引起的基因表达谱各有特征,主要涉及分子转运、信号转导、致病或癌基因等,这对从基因表达层面认识HCVC蛋白的功能及HCV致病机制均有重大帮助。 相似文献
923.
Homology modeling and examination of the effect of the D92E mutation on the H5N1 nonstructural protein NS1 effector domain 总被引:1,自引:0,他引:1
Virulent H5N1 strains of influenza virus often harbor a D92E point mutation in the nonstructural protein NS1. This crucial
mutation has been correlated with increased virulence and/or cytokine resistance, but the structural implications of such
a change are still unclear. Furthermore, NS1 protein could also be a potential target for the development of novel antiviral
agents against H5N1 strains. Therefore, a reasonable 3D model of H5N1 NS1 is important for the understanding of the molecular
basis of increased virulence and the design of novel antiviral agents. Based on the crystal structure of a non-H5N1 NS1 protein,
a model of H5N1 NS1 was developed by homology modeling, molecular mechanics and molecular dynamics simulations. It was found
that the D92E mutation could result in weakened interactions of the carboxylate side chain with other phosphorylated residues,
thereby activating phosphorylation of NS1.
Figure Superposition of snapshots picked from the two molecular dynamic (MD) trajectories: a H5N1 NS1 homology model and b non-H5N1 NS1 crystal structure after 0 (green ribbon), 5 (blue ribbon) and 10 ns (pink ribbon) MD simulation 相似文献
924.
Wang Shujing Liu Yan Lin Xuesong Fu Xue Xu Jianyong Liu Xinghan 《Frontiers of Biology in China》2007,2(3):276-283
To obtain an anti-tumor peptide of Tumstatin and detect its biological activity, the nucleotide sequence encoding 185–203
amino acids (19peptide) of Tumstatin was synthesized and inserted into the fusion protein vector pTYB2. After identification
by sequencing and restriction endonucleases, the recombined vector was transformed into BL-21 (DE3) E. coli competent cells. Transformed E. coli BL-21 (DE3) were induced by isopropyl-β-thiogalactopyranoside (IPTG), and then expressed. By 1,4-dithiothreitol (DTT) reduction,
the soluble 19peptide was obtained from a chitin affinity chromatograph. The biological activity of 19peptide was determined
by 3-[4,5-dimethylthiazol-2-y1]-2,5-diphenytetrazolium bromide (MTT) assay, cell growth curve, the effect of the ascitic fluid
transfevent H22 hepatoma on mice and via histopathological slices. The purified 19peptide directly inhibited proliferation
and migration of murine B16 melanoma cells, SMMC-7721hepatoma carcinoma cells and human umbilical vein endothelial cells (HUVEC).
The tumor inhibition rate of mice ascitic fluid transfevent H22 hepatoma was 48.46%. Histopathological slices showed that
it could promote tumor tissue necrosis and decrease the density of blood vessels. With higher anti-tumor activity, 19peptide
has the potential to become a novel, potent anti-tumor agent.
Translated from Chinese Journal of Biochemistry and Molecular Biology, 2005, 21(3): 322–328 [译自: 中国生物化学与分子生物学学报] 相似文献
925.
Bladder cancer-associated protein gene (BLCAP) is a novel candidate tumor suppressor gene identified from the human bladder
carcinoma. Our previous studies have shown that BLCAP overexpression could inhibit cell growth by inducing apoptosis in HeLa
cells [Zuo Z, Zhao M, Liu J, Gao G, Wu X: Tumor Biol 27: 221–226, 2006]. Such evidence suggests the alterations in BLCAP may
play an important role in tumorigenesis. To further study the biological function of the BLCAP gene, we constructed a recombinant
retroviral vector encoding BLCAP cDNA. Overexpressed BLCAP, via stable infection of exogenous BLCAP, resulted in growth inhibition
of the human tongue cancer cell line Tca8113 in vitro, accompanied by S phase cell cycle arrest and apoptosis. The growth inhibition was correlated with up-regulation of p21WAF1/CIP1 expression and down-regulation of Bcl-XL and Bcl-2 expressions. However, p53 expression and NF-κB activity remained unchanged
post infection. Furthermore, no changes in p53 phosphorylation at Ser46 and nuclear localization, which are critical to p53
function, were observed in BLCAP-overexpressed cells. Taken together, BLCAP may play a role not only in regulating cell proliferation
but also in coordinating apoptosis and cell cycle via a novel way independent of p53 and NF-κB.
Jun Yao and Li Duan contributed equally to this work. 相似文献
926.
Effect of chromium on photosystem 2 in the unicellular green alga, <Emphasis Type="Italic">Chlorella pyrenoidosa</Emphasis> 总被引:1,自引:1,他引:1
We investigated the effect of chromium (20–40 g m−3, 8–72 h) on the photosystem 2 (PS2) activities of Chlorella pyrenoidosa cells. By using chlorophyll fluorescence transients, thermoluminescence, oxygen polarography, and Western blot analysis for
D1 protein we found that inhibition of PS2 can be accounted for by the enhanced photodestruction of the reaction centres in
the cells cultivated in the presence of Cr(VI) at 25 °C in “white light” (18 W m−2). Hence photodestruction of D1 is caused by an enhanced oxidative stress and lipid peroxidation, as indicated by the appearance
of a high-temperature thermoluminescence band. 相似文献
927.
Localization of vacuolar transport receptors and cargo proteins in the Golgi apparatus of developing Arabidopsis embryos 总被引:4,自引:1,他引:4
Hinz G Colanesi S Hillmer S Rogers JC Robinson DG 《Traffic (Copenhagen, Denmark)》2007,8(10):1452-1464
Using immunogold electron microscopy, we have investigated the relative distribution of two types of vacuolar sorting receptors (VSR) and two different types of lumenal cargo proteins, which are potential ligands for these receptors in the secretory pathway of developing Arabidopsis embryos. Interestingly, both cargo proteins are deposited in the protein storage vacuole, which is the only vacuole present during the bent-cotyledon stage of embryo development. Cruciferin and aleurain do not share the same pattern of distribution in the Golgi apparatus. Cruciferin is mainly detected in the cis and medial cisternae, especially at the rims where storage proteins aggregate into dense vesicles (DVs). Aleurain is found throughout the Golgi stack, particularly in the trans cisternae and trans Golgi network where clathrin-coated vesicles (CCVs) are formed. Nevertheless, aleurain was detected in both DV and CCV. VSR-At1, a VSR that recognizes N-terminal vacuolar sorting determinants (VSDs) of the NPIR type, localizes mainly to the trans Golgi and is hardly detectable in DV. Receptor homology-transmembrane-RING H2 domain (RMR), a VSR that recognizes C-terminal VSDs, has a distribution that is very similar to that of cruciferin and is found in DV. Our results do not support a role for VSR-At1 in storage protein sorting, instead RMR proteins because of their distribution similar to that of cruciferin in the Golgi apparatus and their presence in DV are more likely candidates. Aleurain, which has an NPIR motif and seems to be primarily sorted via VSR-At1 into CCV, also possesses putative hydrophobic sorting determinants at its C-terminus that could allow the additional incorporation of this protein into DV. 相似文献
928.
929.
Necrostatin-1 protects against glutamate-induced glutathione depletion and caspase-independent cell death in HT-22 cells 总被引:3,自引:0,他引:3
Xu X Chua CC Kong J Kostrzewa RM Kumaraguru U Hamdy RC Chua BH 《Journal of neurochemistry》2007,103(5):2004-2014
Glutamate, a major excitatory neurotransmitter in the CNS, plays a critical role in neurological disorders such as stroke and Parkinson's disease. Recent studies have suggested that glutamate excess can result in a form of cell death called glutamate-induced oxytosis. In this study, we explore the protective effects of necrostatin-1 (Nec-1), an inhibitor of necroptosis, on glutamate-induced oxytosis. We show that Nec-1 inhibits glutamate-induced oxytosis in HT-22 cells through a mechanism that involves an increase in cellular glutathione (GSH) levels as well as a reduction in reactive oxygen species production. However, Nec-1 had no protective effect on free radical-induced cell death caused by hydrogen peroxide or menadione, which suggests that Nec-1 has no antioxidant effects. Interestingly, the protective effect of Nec-1 was still observed when cellular GSH was depleted by buthionine sulfoximine, a specific and irreversible inhibitor of glutamylcysteine synthetase. Our study further demonstrates that Nec-1 significantly blocks the nuclear translocation of apoptosis-inducing factor (a marker of caspase-independent programmed cell death ) and inhibits the integration of Bcl-2/adenovirus E1B 19 kDa-interacting protein 3 (a pro-death member of the Bcl-2 family) into the mitochondrial membrane. Taken together, these results demonstrate for the first time that Nec-1 prevents glutamate-induced oxytosis in HT-22 cells through GSH related as well as apoptosis-inducing factor and Bcl-2/adenovirus E1B 19 kDa-interacting protein 3-related pathways. 相似文献
930.