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排序方式: 共有144条查询结果,搜索用时 15 毫秒
1.
Senthil Rethinam Srividya S. Wilson Aruni A. Basaran Bahri Jyotsna Thirugnanasambandam Rajendran 《International journal of peptide research and therapeutics》2020,26(4):1863-1870
International Journal of Peptide Research and Therapeutics - The effect of various concentrations of amyloid beta peptide (ABP) in different pH (pH 2, 6, 7, 8, 10) in aging at different time... 相似文献
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Sharan SK Pyle A Coppola V Babus J Swaminathan S Benedict J Swing D Martin BK Tessarollo L Evans JP Flaws JA Handel MA 《Development (Cambridge, England)》2004,131(1):131-142
The role of Brca2 in gametogenesis has been obscure because of embryonic lethality of the knockout mice. We generated Brca2-null mice carrying a human BAC with the BRCA2 gene. This construct rescues embryonic lethality and the mice develop normally. However, there is poor expression of the transgene in the gonads and the mice are infertile, allowing examination of the function of BRCA2 in gametogenesis. BRCA2-deficient spermatocytes fail to progress beyond the early prophase I stage of meiosis. Observations on localization of recombination-related and spermatogenic-related proteins suggest that the spermatocytes undergo early steps of recombination (DNA double strand break formation), but fail to complete recombination or initiate spermiogenic development. In contrast to the early meiotic prophase arrest of spermatocytes, some mutant oocytes can progress through meiotic prophase I, albeit with a high frequency of nuclear abnormalities, and can be fertilized and produce embryos. Nonetheless, there is marked depletion of germ cells in adult females. These studies provide evidence for key roles of the BRCA2 protein in mammalian gametogenesis and meiotic success. 相似文献
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Srividya S Roy RP Basu SK Mukhopadhyay A 《Biochemical and biophysical research communications》2000,268(3):772-777
We have shown that muramyl dipeptide (MDP) conjugated to a 10-mer polyguanylic acid (PolyG) is specifically internalized by macrophages through scavenger receptor (SCR)-mediated endocytosis. Macrophages activated by PolyG-MDP displayed about 20-fold higher cytotoxic activity against nonmacrophage tumor cells compared to that elicited by free MDP. The PolyG-MDP was found to trigger the secretion of higher levels of interleukin-6, interleukin-1alpha, TNF-alpha, and nitric oxide in comparison to free MDP. Addition of antibodies directed against IL-6 and TNF-alpha to macrophage culture completely abrogated the tumoricidal response of PolyG-MDP, indicating that these two cytokines are primarily responsible for bioefficacy. This general approach of PolyG as a vehicle may find wide application in the delivery of genes and antisense oligonucleotides to macrophages. 相似文献
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K. Samuel D. Debashish B. Madhumita G. Padmaja Siva Ram Prasad V. Bhaskara Ramana Murthy P. S. Rao 《In vitro cellular & developmental biology. Plant》2009,45(4):466-473
The propagation of Givotia rottleriformis Griff. is difficult as a result of long seed dormancy associated with poor seed germination. The present study was undertaken
to develop a protocol to overcome seed dormancy by culture of zygotic embryo axes and then develop an efficient method for
micropropagation of Givotia. Best germination frequency (78.3%) was achieved from mature zygotic embryo axes isolated from acid-scarified fresh seeds
when cultured on Murashige and Skoog (MS) medium (half-strength major salts) with 28.9 μM gibberellic acid (GA3). Efficient plant conversion was achieved by transfer of 10-d-old germinated embryos to MS medium (half-strength major salts)
supplemented with 1.2 μM kinetin (KN) and 0.5 μM indole-3-butyric acid (IBA). However, acid scarification of 1-yr-old seeds
decreased the germination frequency of zygotic embryo axes in comparison to those obtained from non-acid-scarified seeds which
germinated (96.2%) and converted into plants (80.3%) on MS basal (half-strength major salts) medium. Multiple shoot bud induction
was achieved by culture of shoot tips derived from in vitro germinated seedlings on MS medium with 0.5 μM thidiazuron for 4 wk, and the shoots elongated after transfer to a secondary
medium with 1.2 μM KN. A maximum number of 7.8 shoots per explant with an average shoot length of 3.2 cm was achieved after
two subcultures on this medium. The in vitro regenerated shoots rooted (41.5%) on half-strength MS medium with 0.5 μM IBA. The in vitro generated seedlings and micropropagated plants were established in soil with a survival frequency of 70% and 60%, respectively. 相似文献
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Adaptation and survival of Trypanosoma brucei requires editing of mitochondrial mRNA by uridylate (U) insertion and deletion. Hundreds of small guide RNAs (gRNAs) direct the mRNA editing at over 3,000 sites. RNA editing is controlled during the life cycle but the regulation of substrate and stage specificity remains unknown. Editing progresses in the 3’ to 5’ direction along the pre-mRNA in blocks, each targeted by a unique gRNA. A critical editing factor is the mitochondrial RNA binding complex 1 (MRB1) that binds gRNA and transiently interacts with the catalytic RNA editing core complex (RECC). MRB1 is a large and dynamic complex that appears to be comprised of distinct but related subcomplexes (termed here MRBs). MRBs seem to share a ‘core’ complex of proteins but differ in the composition of the ‘variable’ proteins. Since some proteins associate transiently the MRBs remain imprecisely defined. MRB1 controls editing by unknown mechanisms, and the functional relevance of the different MRBs is unclear. We previously identified two distinct MRBs, and showed that they carry mRNAs that undergo editing. We proposed that editing takes place in the MRBs because MRBs stably associate with mRNA and gRNA but only transiently interact with RECC, which is RNA free. Here, we identify the first specialized functions in MRBs: 1) 3010-MRB is a major scaffold for RNA editing, and 2) REH2-MRB contains a critical trans-acting RNA helicase (REH2) that affects multiple steps of editing function in 3010-MRB. These trans effects of the REH2 include loading of unedited mRNA and editing in the first block and in subsequent blocks as editing progresses. REH2 binds its own MRB via RNA, and conserved domains in REH2 were critical for REH2 to associate with the RNA and protein components of its MRB. Importantly, REH2 associates with a ~30 kDa RNA-binding protein in a novel ~15S subcomplex in RNA-depleted mitochondria. We use these new results to update our model of MRB function and organization. 相似文献
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Subramanian S Yim YS Liu K Tus K Zhou XJ Wakeland EK 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(2):1062-1072
Sle is a susceptibility locus for systemic autoimmunity derived from the lupus-prone NZM2410 mouse. The New Zealand White-derived suppressive modifier Sles1 was identified as a specific modifier of Sle1 and prevents the development of IgG anti-chromatin autoantibodies mediated by Sle1 on the C57BL/6 (B6) background. Fine mapping of Sles1 with truncated congenic intervals localizes it to a approximately 956-kb segment of mouse chromosome 17. Sles1 completely abrogates the development of activated T and B cell populations in B6.Sle1. Despite this suppression of the Sle1-mediated cell surface activation phenotypes, B6.Sle1 Sles1 splenic B cells still exhibit intrinsic ERK phosphorylation. Classic genetic complementation tests using the nonautoimmmune 129/SvJ mouse suggests that this strain possesses a Sles1 allele complementary to that of New Zealand White, as evidenced by the lack of glomerulonephritis, splenomegaly, and antinuclear autoantibody production seen in (129 x B6.Sle1 Sles1)F(1)s. These findings localize and characterize the suppressive properties of Sles1 and implicate 129 as a useful strain for aiding in the identification of this elusive epistatic modifier gene. 相似文献
10.
Hetero-oligomerization between GABAA and GABAB receptors regulates GABAB receptor trafficking 总被引:4,自引:0,他引:4
Balasubramanian S Teissére JA Raju DV Hall RA 《The Journal of biological chemistry》2004,279(18):18840-18850
The neurotransmitter gamma-aminobutyric acid (GABA) mediates inhibitory signaling in the brain via stimulation of both GABA(A) receptors (GABA(A)R), which are chloride-permeant ion channels, and GABA(B) receptors (GABA(B)R), which signal through coupling to G proteins. Here we report physical interactions between these two different classes of GABA receptor. Association of the GABA(B) receptor 1 (GABA(B)R1) with the GABA(A) receptor gamma2S subunit robustly promotes cell surface expression of GABA(B)R1 in the absence of GABA(B)R2, a closely related GABA(B) receptor that is usually required for efficient trafficking of GABA(B)R1 to the cell surface. The GABA(B)R1/gamma2S complex is not detectably functional when expressed alone, as assessed in both ERK activation assays and physiological analyses in oocytes. However, the gamma2S subunit associates not only with GABA(B)R1 alone but also with the functional GABA(B)R1/GABA(B)R2 heterodimer to markedly enhance GABA(B) receptor internalization in response to agonist stimulation. These findings reveal that the GABA(B)R1/gamma2S interaction results in the regulation of multiple aspects of GABA(B) receptor trafficking, allowing for cross-talk between these two distinct classes of GABA receptor. 相似文献