全文获取类型
收费全文 | 1154篇 |
免费 | 91篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 25篇 |
2020年 | 14篇 |
2019年 | 23篇 |
2018年 | 29篇 |
2017年 | 24篇 |
2016年 | 32篇 |
2015年 | 43篇 |
2014年 | 60篇 |
2013年 | 74篇 |
2012年 | 65篇 |
2011年 | 87篇 |
2010年 | 44篇 |
2009年 | 56篇 |
2008年 | 70篇 |
2007年 | 73篇 |
2006年 | 73篇 |
2005年 | 74篇 |
2004年 | 58篇 |
2003年 | 60篇 |
2002年 | 76篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 30篇 |
1998年 | 12篇 |
1997年 | 15篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1245条查询结果,搜索用时 156 毫秒
991.
Xueyan Li Yoshihiro Nakajima Kazuki Niwa Vadim R. Viviani Yoshihiro Ohmiya 《Protein science : a publication of the Protein Society》2010,19(1):26-33
A luciferase from the railroad worm (Phrixothrix hirtus) is the only red‐emitting bioluminescent enzyme in nature that is advantageous in multicolor luciferase assays and in bioluminescence imaging (BLI). However, it is not used widely in scientific or industrial applications because of its low activity and stability. By using site‐directed mutagenesis, we produced red‐emitting mutants with higher activity and better stability. Compared with the wild‐type (WT), the luminescent activities from extracts of cultured mammalian cells expressing mutant luciferase were 9.8‐fold in I212L/N351K, 8.4‐fold in I212L, and 7.8‐fold in I212L/S463R; and the cell‐based activities were 3.6‐fold in I212L/N351K and 3.4‐fold in N351K. The remaining activities after incubation at 37°C for 10 min were 50.0% for I212L/S463R, 31.8% for I212L, and 23.0% for I212L/N351K, but only 5.2% for WT. To demonstrate an application of I212L/N351K, cell‐based BLI was performed, and the luminescence signal was 3.6‐fold higher than in WT. These results indicate that the mutants might improve the practicability of this signaling in bioassays and BLI. 相似文献
992.
In June–July of 1993 and 1995, pelagic zooplankton dynamics of aglacial lake was investigated. In those years weather conditions
diffferedsubstantially. This resulted not only in a great difference in the watersurface temperature (in 1993, <17.8± 0.47
°C; in 1995, 20.4± 0.33 °C), but also in an increase in the depth of metalimnionzone in 1995 in comparison with 1993. The
ecological efficiency(Ke, the ratio of secondary to primary consumer productions,was 0.28 ± 0.031 in 1993 and 0.21± 0.034 in 1995. The higherKe was accompanied by lowering of spatial structurization,primary and secondary consumer production.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
993.
Landeta O Landajuela A Gil D Taneva S Di Primo C Sot B Valle M Frolov VA Basañez G 《The Journal of biological chemistry》2011,286(10):8213-8230
BAK is a key effector of mitochondrial outer membrane permeabilization (MOMP) whose molecular mechanism of action remains to be fully dissected in intact cells, mainly due to the inherent complexity of the intracellular apoptotic machinery. Here we show that the core features of the BAK-driven MOMP pathway can be reproduced in a highly simplified in vitro system consisting of recombinant human BAK lacking the carboxyl-terminal 21 residues (BAKΔC) and tBID in combination with liposomes bearing an appropriate lipid environment. Using this minimalist reconstituted system we established that tBID suffices to trigger BAKΔC membrane insertion, oligomerization, and pore formation. Furthermore, we demonstrate that tBID-activated BAKΔC permeabilizes the membrane by forming structurally dynamic pores rather than a large proteinaceous channel of fixed size. We also identified two distinct roles played by mitochondrial lipids along the molecular pathway of BAKΔC-induced membrane permeabilization. First, using several independent approaches, we showed that cardiolipin directly interacts with BAKΔC, leading to a localized structural rearrangement in the protein that "primes" BAKΔC for interaction with tBID. Second, we provide evidence that selected curvature-inducing lipids present in mitochondrial membranes specifically modulate the energetic expenditure required to create the BAKΔC pore. Collectively, our results support the notion that BAK functions as a direct effector of MOMP akin to BAX and also adds significantly to the growing evidence indicating that mitochondrial membrane lipids are actively implicated in BCL-2 protein family function. 相似文献
994.
Marina V. Kasaikina Dmitri E. Fomenko Vyacheslav M. Labunskyy Salil A. Lachke Wenya Qiu Juliet A. Moncaster Jie Zhang Mark W. Wojnarowicz Jr. Sathish Kumar Natarajan Mikalai Malinouski Ulrich Schweizer Petra A. Tsuji Bradley A. Carlson Richard L. Maas Marjorie F. Lou Lee E. Goldstein Dolph L. Hatfield Vadim N. Gladyshev 《The Journal of biological chemistry》2011,286(38):33203-33212
The 15-kDa selenoprotein (Sep15) is a thioredoxin-like, endoplasmic reticulum-resident protein involved in the quality control of glycoprotein folding through its interaction with UDP-glucose:glycoprotein glucosyltransferase. Expression of Sep15 is regulated by dietary selenium and the unfolded protein response, but its specific function is not known. In this study, we developed and characterized Sep15 KO mice by targeted removal of exon 2 of the Sep15 gene coding for the cysteine-rich UDP-glucose:glycoprotein glucosyltransferase-binding domain. These KO mice synthesized a mutant mRNA, but the shortened protein product could be detected neither in tissues nor in Sep15 KO embryonic fibroblasts. Sep15 KO mice were viable and fertile, showed normal brain morphology, and did not activate endoplasmic reticulum stress pathways. However, parameters of oxidative stress were elevated in the livers of these mice. We found that Sep15 mRNA was enriched during lens development. Further phenotypic characterization of Sep15 KO mice revealed a prominent nuclear cataract that developed at an early age. These cataracts did not appear to be associated with severe oxidative stress or glucose dysregulation. We suggest that the cataracts resulted from an improper folding status of lens proteins caused by Sep15 deficiency. 相似文献
995.
Lee BC Lobanov AV Marino SM Kaya A Seravalli J Hatfield DL Gladyshev VN 《The Journal of biological chemistry》2011,286(21):18747-18755
Selenocysteine (Sec) residues occur in thiol oxidoreductase families, and functionally characterized selenoenzymes typically have a single Sec residue used directly for redox catalysis. However, how new Sec residues evolve and whether non-catalytic Sec residues exist in proteins is not known. Here, we computationally identified several genes with multiple Sec insertion sequence (SECIS) elements, one of which was a methionine-R-sulfoxide reductase (MsrB) homolog from Metridium senile that has four in-frame UGA codons and two nearly identical SECIS elements. One of the UGA codons corresponded to the conserved catalytic Sec or Cys in MsrBs, whereas the three other UGA codons evolved recently and had no homologs with Sec or Cys in these positions. Metabolic (75)Se labeling showed that all four in-frame UGA codons supported Sec insertion and that both SECIS elements were functional and collaborated in Sec insertion at each UGA codon. Interestingly, recombinant M. senile MsrB bound iron, and further analyses suggested the possibility of binding an iron-sulfur cluster by the protein. These data show that Sec residues may appear transiently in genes containing SECIS elements and be adapted for non-catalytic functions. 相似文献
996.
Klenchin VA Frye JJ Jones MH Winey M Rayment I 《The Journal of biological chemistry》2011,286(20):18240-18250
The spindle pole body of the budding yeast Saccharomyces cerevisiae has served as a model system for understanding microtubule organizing centers, yet very little is known about the molecular structure of its components. We report here the structure of the C-terminal domain of the core component Cnm67 at 2.3 Å resolution. The structure determination was aided by a novel approach to crystallization of proteins containing coiled-coils that utilizes globular domains to stabilize the coiled-coils. This enhances their solubility in Escherichia coli and improves their crystallization. The Cnm67 C-terminal domain (residues Asn-429—Lys-581) exhibits a previously unseen dimeric, interdigitated, all α-helical fold. In vivo studies demonstrate that this domain alone is able to localize to the spindle pole body. In addition, the structure reveals a large functionally indispensable positively charged surface patch that is implicated in spindle pole body localization. Finally, the C-terminal eight residues are disordered but are critical for protein folding and structural stability. 相似文献
997.
Gottar-Guillier M Dodeller F Huesken D Iourgenko V Mickanin C Labow M Gaveriaux S Kinzel B Mueller M Alitalo K Littlewood-Evans A Cenni B 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(10):6014-6023
Inflammatory cytokines like TNF play a central role in autoimmune disorders such as rheumatoid arthritis. We identified the tyrosine kinase bone marrow kinase on chromosome X (BMX) as an essential component of a shared inflammatory signaling pathway. Transient depletion of BMX strongly reduced secretion of IL-8 in cell lines and primary human cells stimulated by TNF, IL-1β, or TLR agonists. BMX was required for phosphorylation of p38 MAPK and JNK, as well as activation of NF-κB. The following epistasis analysis indicated that BMX acts downstream of or at the same level as the complex TGF-β activated kinase 1 (TAK1)-TAK1 binding protein. At the cellular level, regulation of the IL-8 promoter required the pleckstrin homology domain of BMX, which could be replaced by an ectopic myristylation signal, indicating a requirement for BMX membrane association. In addition, activation of the IL-8 promoter by in vitro BMX overexpression required its catalytic activity. Genetic ablation of BMX conferred protection in the mouse arthritis model of passive K/BxN serum transfer, confirming that BMX is an essential mediator of inflammation in vivo. However, genetic replacement with a catalytically inactive BMX allele was not protective in the same arthritis animal model. We conclude that BMX is an essential component of inflammatory cytokine signaling and that catalytic, as well as noncatalytic functions of BMX are involved. 相似文献
998.
Delta sleep inducing peptide (WAGGDASGE, DSIP) is a well known multifunctional regulatory peptide. Numerous studies have confirmed its stress-protective and adaptive activity which is independent of the origin or nature of the stress or other harmful factors. However, the biosynthetic origin of DSIP remains obscure, since nothing is known of its protein precursor(s) and their encoding gene(s). We have performed a comprehensive analysis of available gene and protein databases for homologous peptide sites within mammalian resources including man. A family of Jumonji C (JmjC)-domain-containing histone demethylases was shown to contain a sequence fragment closely homologous to DSIP. One type of these ubiquitous and phylogenetically ancient proteins encoded by JMJD1B gene includes the WKGGNASGE sequence that differs from DSIP by only 2 amino acid residues in positions 2 and 5. The respective peptide was synthesized and its biological effects were evaluated in a preliminary way in the forced swimming and antitoxic tests. We suggest that the histone demethylases of the JmjC-group containing DSIP-related region can be considered as possible protein precursors of endogenous peptides with DSIP-like activity. 相似文献
999.
The capacity of HDAC inhibitor sodium butyrate to induce senescence in cells derived from rat embryonic fibroblasts transformed by E1A+E1B19 kDa oncogenes has been studied. These transformants are resistant to apoptosis in response to gamma-irradiation and growth factor deprivation. The process of cell senescence was investigated by the analysis of cell growth curves, G1/S and G2/M cell cycle arrest, and senescent associated beta-galactosidase expression. The irreversibility of sodium butyrate antiproliferative activity was analyzed by clonogenic assay. We show that sodium butyrate suppresses proliferation and induces senescence in the E1A+E1B19 kDa transformed cells. Interestingly, NaB induces growth arrest due to accumulation of cells in G2/M phase, these cells are not tetraploid but mainly binuclear. Thus, in case of NaB induced senescence in E1A+E1B19 kDa transformed fibroblasts, the observed suppression of cell proliferation may be the result of cytokinesis failure leading to formation of binuclear and multinuclear cells incapable to proliferate. 相似文献
1000.
Reino DC Pisarenko V Palange D Doucet D Bonitz RP Lu Q Colorado I Sheth SU Chandler B Kannan KB Ramanathan M Xu da Z Deitch EA Feinman R 《PloS one》2011,6(8):e14829