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41.
Numerical Taxonomy of Heterotrophic Bacteria Growing in Association with Continuous-Culture Chlorella sorokiniana 总被引:2,自引:1,他引:1 下载免费PDF全文
Twenty-nine cultures isolated from nonaxenic growths of Chlorella sorokiniana (Shihira and Krauss) and eight reference cultures were tested for 150 morphological and biochemical characteristics. The taxonomic data were subjected to computer analysis from which five major clusters were identified. The bacterial isolates have been placed in the genera: Pseudomonas, Acinetobacter, Flavobacterium, and Bacillus. Amino acid requirements of four strains from the test set were determined. 相似文献
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Bosc DG Graham KC Saulnier RB Zhang C Prober D Gietz RD Litchfield DW 《The Journal of biological chemistry》2000,275(19):14295-14306
The catalytic subunits of protein kinase CK2, CK2alpha and CK2alpha', are closely related to each other but exhibit functional specialization. To test the hypothesis that specific functions of CK2alpha and CK2alpha' are mediated by specific interaction partners, we used the yeast two-hybrid system to identify CK2alpha- or CK2alpha'-binding proteins. We report the identification and characterization of a novel CK2-interacting protein, designated CKIP-1, that interacts with CK2alpha, but not CK2alpha', in the yeast two-hybrid system. CKIP-1 also interacts with CK2alpha in vitro and is co-immunoprecipitated from cell extracts with epitope-tagged CK2alpha and an enhanced green fluorescent protein fusion protein encoding CKIP-1 (i.e. EGFP-CKIP-1) when they are co-expressed. CK2 activity is detected in anti-CKIP-1 immunoprecipitates performed with extracts from non-transfected cells indicating that CKIP-1 and CK2 interact under physiological conditions. The CKIP-1 cDNA is broadly expressed and encodes a protein with a predicted molecular weight of 46,000. EGFP-CKIP-1 is localized within the nucleus and at the plasma membrane. The plasma membrane localization is dependent on the presence of an amino-terminal pleckstrin homology domain. We postulate that CKIP-1 is a non-enzymatic regulator of one isoform of CK2 (i.e. CK2alpha) with a potential role in targeting CK2alpha to a particular cellular location. 相似文献
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J E Graves P M Clarkson P Litchfield J P Kirwan J P Norton 《European journal of applied physiology and occupational physiology》1987,56(6):657-661
The purpose of this study was to examine the relationship between the muscle mass involved in exercise and post-exercise serum creatine kinase (CK) elevation. Twelve untrained college-aged men completed three isometric exercises: one arm flexion (OAF), two arm flexion (TAF) and one leg knee extension (OLE). These exercises were balanced over subjects and days and separated by two week intervals. Each exercise consisted of 40 maximal isometric concentrations lasting for 10 s with a 20 s rest between contractions. Relative increases in serum CK for OAF, TAF, and OLE were 181 +/- 70% (SD), 222 +/- 69% and 297 +/- 67%, respectively. An ANOVA using a latin square design for analysis of carry over effects showed that these CK increases were not significantly different (p greater than 0.05). However, the increase in serum CK following the first exercise (379 +/- 90%), regardless of what it was (OAF, TAF, or OLE), was significantly greater (p less than 0.05) than those following bouts 2 and 3 (155 +/- 29%; 167 +/- 54%). Regression analysis indicated that post-exercise serum CK elevation was not related to the amount of muscle mass involved in the exercise (r = 0.30, p greater than 0.05) nor to muscle tension developed (r = 0.28, p greater than 0.05). We conclude that post-exercise serum CK elevation is not necessarily related to the muscle mass involved in the exercise. Because each exercise involved the use of different muscle groups, factors outside the exercising muscle may contribute to post-exercise serum enzyme activity. 相似文献
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Laszlo Gyenis Jacob P. Turowec Maria Bretner David W. Litchfield 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(7):1352-1358
Since protein kinases have been implicated in numerous human diseases, kinase inhibitors have emerged as promising therapeutic agents. Despite this promise, there has been a relative lag in the development of unbiased strategies to validate both inhibitor specificity and the ability to inhibit target activity within living cells. To overcome these limitations, our efforts have been focused on the development of systematic strategies that employ chemical and functional proteomics. We utilized these strategies to evaluate small molecule inhibitors of protein kinase CK2, a constitutively active kinase that has recently emerged as target for anti-cancer therapy in clinical trials. Our chemical proteomics strategies used ATP or CK2 inhibitors immobilized on sepharose beads together with mass spectrometry to capture and identify binding partners from cell extracts. These studies have verified that interactions between CK2 and its inhibitors occur in complex mixtures. However, in the case of CK2 inhibitors related to 4,5,6,7-tetrabromo-1H-benzotriazole (TBB), our work has also revealed off-targets for the inhibitors. To complement these studies, we devised functional proteomics approaches to identify proteins that exhibit decreases in phosphorylation when cells are treated with CK2 inhibitors. To identify and validate those proteins that are direct substrates for CK2, we have also employed mutants of CK2 with decreased inhibitor sensitivity. Overall, our studies have yielded systematic platforms for studying CK2 inhibitors which we believe will foster efforts to define the biological functions of CK2 and to rigorously investigate its potential as a candidate for molecular-targeted therapy. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases (2012). 相似文献
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A Dickinson K Y Yeung J Donoghue M J Baker R DW Kelly M McKenzie T G Johns J C St. John 《Cell death and differentiation》2013,20(12):1644-1653
As stem cells undergo differentiation, mitochondrial DNA (mtDNA) copy number is strictly regulated in order that specialized cells can generate appropriate levels of adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS) to undertake their specific functions. It is not understood whether tumor-initiating cells regulate their mtDNA in a similar manner or whether mtDNA is essential for tumorigenesis. We show that human neural stem cells (hNSCs) increased their mtDNA content during differentiation in a process that was mediated by a synergistic relationship between the nuclear and mitochondrial genomes and results in increased respiratory capacity. Differentiating multipotent glioblastoma cells failed to match the expansion in mtDNA copy number, patterns of gene expression and increased respiratory capacity observed in hNSCs. Partial depletion of glioblastoma cell mtDNA rescued mtDNA replication events and enhanced cell differentiation. However, prolonged depletion resulted in impaired mtDNA replication, reduced proliferation and induced the expression of early developmental and pro-survival markers including POU class 5 homeobox 1 (OCT4) and sonic hedgehog (SHH). The transfer of glioblastoma cells depleted to varying degrees of their mtDNA content into immunocompromised mice resulted in tumors requiring significantly longer to form compared with non-depleted cells. The number of tumors formed and the time to tumor formation was relative to the degree of mtDNA depletion. The tumors derived from mtDNA depleted glioblastoma cells recovered their mtDNA copy number as part of the tumor formation process. These outcomes demonstrate the importance of mtDNA to the initiation and maintenance of tumorigenesis in glioblastoma multiforme. 相似文献
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A novel haloalkaliphilic, thermostable serine protease was purified from the extreme halophilic archaeon, Halogeometricum borinquense strain TSS101. The protease was isolated from a stationary phase culture, purified 116-fold with 18% yield and characterized biochemically. The molecular mass of the purified enzyme was estimated to be 86 kDa. The enzyme showed the highest activity at 60 degrees C and pH 10.0 in 20% NaCl. The enzyme had high activity over the pH range from 6.0 to 10.0. Enzymatic activity was strongly inhibited by 1 mM phenyl methylsulfonyl fluoride, but activity was increased 59% by 0.1% cetyltrimethylammonium bromide. The enzyme exhibited relatively high thermal stability, retaining 80% of its activity after 1 h at 90 degrees C. Thermostability increased in the presence of Ca2+. The stability of the enzyme was maintained in 10% sucrose and in the absence of NaCl. 相似文献