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1.
We present a single-step procedure for the specific mass labeling of unblocked protein N termini. We show that the dye fluorescamine, which is commonly assumed to require mildly alkaline conditions for undergoing a nonspecific reaction with α- and ε-amino groups associated with amino acids, in fact shows a specific reaction only with α-amino groups present at protein N termini when mildly acidic conditions are used. We use this finding to label, identify, and sequence the trypsinolysis-derived N-terminal peptide of lysozyme, using only mass spectrometry, to illustrate how this method could be used with other proteins. 相似文献
2.
J M Al-Hassan M Afzal M Ali M Thomson T Fatima S Fayad R S Criddle 《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,85(1):41-47
Lipids associated with a threat induced epidermal gel secretion from the catfish, Arius thalassinus, have been analyzed. Phospholipids, neutral lipids and glycolipids are all present and each of these subclasses has been analyzed by thin layer and gas chromatography with a general similarity with membrane lipids being noted. The epidermal gel lipids differed from total liver lipids of the catfish. Fatty acid analysis showed the gel lipid to be rich in the unsaturated fatty acids: oleate (omega 7, C18:1), arachidonate (omega 6, C20:4), and docosahexaenoate (omega 3, C22:6). Some prostaglandins were quantitated in lipid extracts from the epidermal gel. 相似文献
3.
T. Fatima Mitterboeck Sarah J. Adamowicz 《Proceedings. Biological sciences / The Royal Society》2013,280(1767)
The loss of flight ability has occurred thousands of times independently during insect evolution. Flight loss may be linked to higher molecular evolutionary rates because of reductions in effective population sizes (Ne) and relaxed selective constraints. Reduced dispersal ability increases population subdivision, may decrease geographical range size and increases (sub)population extinction risk, thus leading to an expected reduction in Ne. Additionally, flight loss in birds has been linked to higher molecular rates of energy-related genes, probably owing to relaxed selective constraints on energy metabolism. We tested for an association between insect flight loss and molecular rates through comparative analysis in 49 phylogenetically independent transitions spanning multiple taxa, including moths, flies, beetles, mayflies, stick insects, stoneflies, scorpionflies and caddisflies, using available nuclear and mitochondrial protein-coding DNA sequences. We estimated the rate of molecular evolution of flightless (FL) and related flight-capable lineages by ratios of non-synonymous-to-synonymous substitutions (dN/dS) and overall substitution rates (OSRs). Across multiple instances of flight loss, we show a significant pattern of higher dN/dS ratios and OSRs in FL lineages in mitochondrial but not nuclear genes. These patterns may be explained by relaxed selective constraints in FL ectotherms relating to energy metabolism, possibly in combination with reduced Ne. 相似文献
4.
Maria de Fatima Bonaldo Pierre Jelenc Long Su Lee Lawton M. -T. Wu Dorothy Warburton Marcelo Bento Soares 《Human genetics》1996,97(4):441-452
A study was conducted on the feasibility of isolating genes and pseudogenes that map to chromosome 13 by a hybridization-based approach using a 13-specific library and pools of repeat-free cDNA clones. Five pairs of cDNA and chromosome 13 genomic clones were identified and characterized. Partial or full-length sequence was derived from all cDNAs, and database searches were performed for putative gene identification. Partial sequence was also obtained from the chromosome 13 genomic clones for comparison with those of the hybridizing cDNAs. As a result of these analyses we identified three genes, a putative homologue of a porcine mRNA encoding an unidentified hepatic protein, a putative homologue of a yeast integral membrane protein, and a gene for a translationally controlled tumor protein, and two processed pseudogenes, ribosomal proteins L23a and S3a. The latter was formerly identified as the v-fos transformation effector gene, Fte-1, and recently cited as a possible candidate for the BRCA2 gene on chromosome 13. All genes and pseudogenes were localized to cytogenetic bands by in situ hybridization of metaphase chromosomes with probes derived from the chromosome 13 genomic clones. 相似文献
5.
Hanna E. Abboud Giuseppe Grandaliano Massimo Pinzani Thomas Knauss Glenn F. Pierce Fatima Jaffer 《Journal of cellular physiology》1994,158(1):140-150
Platelet-derived growth factor (PDGF) occurs as homodimers or heterodimers of related polypeptide chains PDGF-BB, -AA, and -AB. There are two receptors that bind PDGF, termed alpha and beta. The beta receptor recognizes PDGF B chain and is dimerized in response to PDGF BB. The alpha receptor recognizes PDGF B as well as A chains and can be dimerized by the three dimeric forms of PDGF AA, AB, and BB. To characterize PDGF receptor signaling mechanisms and biologic activities in human mesangial cells (MC), we explored the effects of the three PDGF isoforms on DNA synthesis, phospholipase C activation, and PDGF protooncogene induction. PDGF-BB homodimer and AB heterodimer induced a marked increase in DNA synthesis, activation of phsopholipase C, and autoinduction of PDGF A and B chain mRNAs, whereas PDGF-AA homodimer was without effect. The lack of response to PDGF AA could be accounted for by down regulation of the PDGF-alpha receptor since preincubation of MC with suramin restored PDGF AA-induced DNA synthesis. Ligand binding studies demonstrate specific binding of labeled PDGF BB and AB and to a lower extent PDGF AA isoforms to mesangial cells. These results are consistent with predominant expression of PDGF beta receptor in MC, which is linked to phospholipase-C activation. The potent biologic effects of PDGF-AB heterodimer in cells that express very few alpha receptors and do not respond to PDGF AA are somewhat inconsistent with the currently accepted model of PDGF receptor interaction and suggest the presence of additional mechanisms for PDGF isoform binding and activation. © 1994 Wiley-Liss, Inc. 相似文献
6.
Imane Nait Irahal Dounia Darif Ismail Guenaou Fouzia Hmimid Fatima azzahra Lahlou Fatima Ez-zahra Ousaid Fatima Abdou-Allah Lamiaa Aitsi Khadija Akarid Noureddine Bourhim 《化学与生物多样性》2023,20(3):e202201169
Type 1 diabetes is characterized by insulin deficiency due to the destruction of pancreatic β cells, leading to hyperglycemia, which in turn induces vascular complications. In the current study, we investigated the effect of intraperitoneal administration of clove essential oil (CEO: 20 mg/kg body weight) on certain oxidative stress and glucose metabolism enzymes, as well as the expression of proinflammatory mediators. Administration of CEO to diabetic rats showed a significant decline in blood glucose levels, total cholesterol, and xanthine oxidase, compared to the streptozotocin group. Furthermore, these treated rats elicited a notable attenuation in the levels of lipid peroxides, and thiols groups in both liver and brain tissues. The activities of antioxidant and metabolic enzymes were reverted to normality in diabetic upon CEO administration. In addition to its protective effects on red blood cell hemolysis, CEO is a potent α-amylase inhibitor with an IC50=298.0±2.75 μg/mL. Also, treatment of diabetic rats with CEO significantly reduced the iNOS expression in the spleen. Our data showed that CEO has potential beneficial effects on diabetes, which can possibly prevent the pathogenesis of diabetic micro- and macrovascular complications. 相似文献
7.
8.
Successful phytoremediation of crude-oil contaminated soil at an oil exploration and production company by plants-bacterial synergism 总被引:1,自引:0,他引:1
Kaneez Fatima Asma Imran Imran Amin Qaiser M. Khan 《International journal of phytoremediation》2018,20(7):675-681
Phytoremediation is a promising approach for the cleanup of soil contaminated with petroleum hydrocarbons. This study aimed to develop plant-bacterial synergism for the successful remediation of crude oil-contaminated soil. A consortia of three endophytic bacteria was augmented to two grasses, Leptochloa fusca and Brachiaria mutica, grown in oil-contaminated soil (46.8 g oil kg?1 soil) in the vicinity of an oil exploration and production company. Endophytes augmentation improved plant growth, crude oil degradation, and soil health. Maximum oil degradation (80%) was achieved with B. mutica plants augmented with the endophytes and it was significantly (P < 0.05) higher than the use of plants or bacteria individually. Moreover, endophytes showed more persistence, the abundance and expression of alkB gene in the rhizosphere as well as in the endosphere of the tested plants than in unvegetated soil. A positive relationship (r = 0.70) observed between gene expression and crude oil reduction indicates that catabolic gene expression is important for hydrocarbon mineralization. This investigation showed that the use of endophytes with appropriate plant is an effective strategy for the cleanup of oil-contaminated soil under field conditions. 相似文献
9.
Extracellular invertase is an essential component of cytokinin-mediated delay of senescence 总被引:24,自引:0,他引:24 下载免费PDF全文
Balibrea Lara ME Gonzalez Garcia MC Fatima T Ehness R Lee TK Proels R Tanner W Roitsch T 《The Plant cell》2004,16(5):1276-1287
Leaf senescence is the final stage of leaf development in which the nutrients invested in the leaf are remobilized to other parts of the plant. Whereas senescence is accompanied by a decline in leaf cytokinin content, exogenous application of cytokinins or an increase of the endogenous concentration delays senescence and causes nutrient mobilization. The finding that extracellular invertase and hexose transporters, as the functionally linked enzymes of an apolasmic phloem unloading pathway, are coinduced by cytokinins suggested that delay of senescence is mediated via an effect on source-sink relations. This hypothesis was further substantiated in this study by the finding that delay of senescence in transgenic tobacco (Nicotiana tabacum) plants with autoregulated cytokinin production correlates with an elevated extracellular invertase activity. The finding that the expression of an extracellular invertase under control of the senescence-induced SAG12 promoter results in a delay of senescence demonstrates that effect of cytokinins may be substituted by these metabolic enzymes. The observation that an increase in extracellular invertase is sufficient to delay leaf senescence was further verified by a complementing functional approach. Localized induction of an extracellular invertase under control of a chemically inducible promoter resulted in ectopic delay of senescence, resembling the naturally occurring green islands in autumn leaves. To establish a causal relationship between cytokinins and extracellular invertase for the delay of senescence, transgenic plants were generated that allowed inhibition of extracellular invertase in the presence of cytokinins. For this purpose, an invertase inhibitor was expressed under control of a cytokinin-inducible promoter. It has been shown that senescence is not any more delayed by cytokinin when the expression of the invertase inhibitor is elevated. This finding demonstrates that extracellular invertase is required for the delay of senescence by cytokinins and that it is a key element of the underlying molecular mechanism. 相似文献
10.