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51.
Heath E Brown WA Jensen SR Bratty MP 《Journal of industrial microbiology & biotechnology》2006,33(3):197-207
The biodegradation of chlorinated alkanes was studied under oxic conditions with the objective of identifying favorable and
unfavorable intramolecular chlorination sequences with respect to the enzymes studied. Several dehalogenating bacterial strains
were screened for their ability to degrade middle-chain polychlorinated alkanes as well as a commercial mixture. Of the organisms
tested, the most promising was Pseudomonas sp. strain 273, which possesses an oxygenolytic dehalogenase. The effects of carbon chain length (C6–C16), halogen position, and overall chlorine content (14–61% w/w) were examined using both commercially available compounds and
molecules synthesized in our laboratory. The effects of co-substrates, solvents, and inducing agents were also studied. The
results with pure chlorinated alkanes showed that the relative positions of the chlorine atoms strongly influenced the total
amount of dehalogenation achieved. The greatest dehalogenation yields were associated with terminally chlorinated alkanes.
The α- and α,ω-chlorinated compounds yielded similar results. Vicinal chlorination had the most dramatic impact on degradation.
When present on both ends or at the center of the molecule, no dehalogenation was detected. Although partial dehalogenation
of 1,2-dichlorodecane was observed, it was likely due to a combination of β-oxidation and an abiotic mechanism. Cereclor S52
was appreciably dehalogenated in shake flasks only when 1,10-dichlorodecane was present as a co-substrate and after increasing
the oil surface area through mechanical emulsification, demonstrating the importance of abiotic factors in degrading commercial
polychlorinated alkane mixtures. 相似文献
52.
Killen SS Marras S Steffensen JF McKenzie DJ 《Proceedings. Biological sciences / The Royal Society》2012,279(1727):357-364
The schooling behaviour of fish is of great biological importance, playing a crucial role in the foraging and predator avoidance of numerous species. The extent to which physiological performance traits affect the spatial positioning of individual fish within schools is completely unknown. Schools of juvenile mullet Liza aurata were filmed at three swim speeds in a swim tunnel, with one focal fish from each school then also measured for standard metabolic rate (SMR), maximal metabolic rate (MMR), aerobic scope (AS) and maximum aerobic swim speed. At faster speeds, fish with lower MMR and AS swam near the rear of schools. These trailing fish required fewer tail beats to swim at the same speed as individuals at the front of schools, indicating that posterior positions provide hydrodynamic benefits that reduce swimming costs. Conversely, fish with high aerobic capacity can withstand increased drag at the leading edge of schools, where they could maximize food intake while possibly retaining sufficient AS for other physiological functions. SMR was never related to position, suggesting that high maintenance costs do not necessarily motivate individuals to occupy frontal positions. In the wild, shifting of individuals to optimal spatial positions during changing conditions could influence structure or movement of entire schools. 相似文献
53.
Bringans S Eriksen S Kendrick T Gopalakrishnakone P Livk A Lock R Lipscombe R 《Proteomics》2008,8(5):1081-1096
Venoms have evolved over millions of years into potent cocktails of bioactive peptides and proteins. These compounds can be of great value to the pharmaceutical industry for numerous clinical applications. In this study, a novel proteomic - bioinformatic approach was utilised, where chromatography followed by gel electrophoresis was utilised to separate the venom peptides/proteins of Heterometrus longimanus (Asian black scorpion). Purified peptides were analysed by tandem mass spectrometry, de novo sequenced and then homology matched against known peptides in the Swiss-Prot protein database. Numerous potentially biologically active peptide matches were discovered, and a simple scoring system applied to putatively assign functions to the peptides. As a validation of this approach, the functional composition of the experimentally derived proteome is similar to that of other scorpions, and contains a potent mix of toxins, antimicrobials and ionic channel inhibitors. 相似文献
54.
Two uncoiler regions, induced by adenovirus 12, have been identified on human chromosome 1 at 1q42 and 1p36. In situ hybridization with [125I-5S]-rRNA places the 5S genes more accurately at 1q42–43 immediately distal to the uncoiled site, 1q42. 相似文献
55.
56.
Aquaporins in complex tissues. I.Developmental patterns in respiratory and glandular tissues of rat 总被引:14,自引:0,他引:14
King Landon S.; Nielsen Soren; Agre Peter 《American journal of physiology. Cell physiology》1997,273(5):C1541
Developmentalexpression of aquaporin water transport proteins is not well understoodin respiratory tract or secretory glands; here we define aquaporinprotein ontogeny in rat. Expression of aquaporin-3 (AQP3), AQP4, andAQP5 proteins occurs within 2 wk after birth, whereas AQP1 firstappears before birth. In most tissues, aquaporin protein expressionincreases progressively, although transient high-level expression isnoted in distal lung (AQP4 at postnatal day+2) and trachea (AQP5 at postnatalday +21 and AQP3 at postnatal day+42). In mature animals, AQP5 is abundant in distallung and salivary glands, AQP3 and AQP4 are present in trachea, andAQP1 is present in all of these tissues except salivary glands.Surprisingly, all four aquaporin proteins are highly abundant innasopharynx. Unlike AQP1, corticosteroids did not induce expression ofAQP3, AQP4, or AQP5 in lung. Our results seemingly implicate aquaporinsin proximal airway humidification, glandular secretion, and perinatalclearance of fluid from distal airways. However, the studies underscorea need for detailed immunohistochemical characterizations anddefinitive functional studies. 相似文献
57.
Pedersen LE Harndahl M Rasmussen M Lamberth K Golde WT Lund O Nielsen M Buus S 《Immunogenetics》2011,63(12):821-834
In all vertebrate animals, CD8+ cytotoxic T lymphocytes (CTLs) are controlled by major histocompatibility complex class I (MHC-I) molecules. These are highly
polymorphic peptide receptors selecting and presenting endogenously derived epitopes to circulating CTLs. The polymorphism
of the MHC effectively individualizes the immune response of each member of the species. We have recently developed efficient
methods to generate recombinant human MHC-I (also known as human leukocyte antigen class I, HLA-I) molecules, accompanying
peptide-binding assays and predictors, and HLA tetramers for specific CTL staining and manipulation. This has enabled a complete
mapping of all HLA-I specificities (“the Human MHC Project”). Here, we demonstrate that these approaches can be applied to
other species. We systematically transferred domains of the frequently expressed swine MHC-I molecule, SLA-1*0401, onto a
HLA-I molecule (HLA-A*11:01), thereby generating recombinant human/swine chimeric MHC-I molecules as well as the intact SLA-1*0401
molecule. Biochemical peptide-binding assays and positional scanning combinatorial peptide libraries were used to analyze
the peptide-binding motifs of these molecules. A pan-specific predictor of peptide–MHC-I binding, NetMHCpan, which was originally developed to cover the binding specificities of all known HLA-I molecules, was successfully used to
predict the specificities of the SLA-1*0401 molecule as well as the porcine/human chimeric MHC-I molecules. These data indicate
that it is possible to extend the biochemical and bioinformatics tools of the Human MHC Project to other vertebrate species. 相似文献
58.
Kim YH Jha KN Mandal A Vanage G Farris E Snow PL Klotz K Naaby-Hansen S Flickinger CJ Herr JC 《Developmental biology》2005,286(1):46-56
CABYR is a highly polymorphic, sperm flagellar calcium-binding protein that is tyrosine as well as serine/threonine phosphorylated during capacitation. Six alternative splice variants of human CABYR (I-VI) have previously been identified, involving two coding regions, CR-A and CR-B, separated by an intervening stop codon. It is presently unknown if proteins encoded by the predicted coding region B of CABYR are translated during spermiogenesis, where they localize, or which CABYR isoforms bind calcium. Immunofluorescent and electron microscopic studies using polyclonal antibodies generated to the recombinant c-terminal 198 aa CABYR-B localized the isoforms containing CABYR-B to the ribs and longitudinal columns of the fibrous sheath in the principal piece of the flagellum. Antisera to recombinant CABYR-A and CABYR-B proteins recognized distinct populations of CABYR isoforms encoded by either CR-A alone and/or CR-B as well as a common population of CABYR isoforms. Only the recombinant CABYR-A and not the CABYR-B bound calcium in vitro, which is consistent with the hypothesis that CABYR-A is the only form that binds calcium in sperm. These observations confirmed that, despite the presence of the stop codon in CR-A, splice variants containing CR-B are expressed during spermiogenesis and assemble into the fibrous sheath of the principal piece; however, calcium binding occurs only to those CABYR isoforms containing CABYR-A. 相似文献
59.
Protoplasts of Phaseolus vulgaris L. (Top Crop), infected with bean golden mosaic virus, were isolated and fixed by various methods for in situ hybridization. An iodine-125 labeled probe was made from the replicative form of the virus. The localization and quantitation was done by autoradiography. Cell wall removal lowered the background and allowed a more accurate analysis. RNase was used to eliminate the possibility of hybrids to RNA. The evidence suggests a sequence of virus movements starting from rough endoplasm reticulum, moving to the nuclear membrane, and finally with the highest concentration inside the nucleus.Abbreviations BGMV
bean golden mosaic virus
- rfBGMV or rfDNA
replicative double-stranded DNA virus
- ssDNA
single-stranded virus 相似文献
60.
Caspase-mediated parkin cleavage in apoptotic cell death 总被引:1,自引:0,他引:1
Kahns S Lykkebo S Jakobsen LD Nielsen MS Jensen PH 《The Journal of biological chemistry》2002,277(18):15303-15308
The parkin protein is important for the survival of the neurons that degenerate in Parkinson's disease as demonstrated by disease-causing lesions in the parkin gene. The Chinese hamster ovary and the SH-SY5Y cell line stably expressing recombinant human parkin combined with epitope-specific parkin antibodies were used to investigate the proteolytic processing of human parkin during apoptosis by immunoblotting. Parkin is cleaved during apoptosis induced by okadaic acid, staurosporine, and camptothecin, thereby generating a 38-kDa C-terminal fragment and a 12-kDa N-terminal fragment. The cleavage was not significantly affected by the disease-causing mutations K161N, G328E, T415N, and G430D and the polymorphism R366W. Parkin and its 38-kDa proteolytic fragment is preferentially associated with vesicles, thereby indicating that cleavage is a membrane-associated event. The proteolysis is sensitive to inhibitors of caspases. The cleavage site was mapped by site-directed mutagenesis of potential aspartic residues and revealed that mutation of Asp-126 alone abrogated the parkin cleavage. The tetrapeptide aldehyde LHTD-CHO, representing the amino acid sequence N-terminal to the putative cleavage site was an efficient inhibitor of parkin cleavage. This suggests that parkin function is compromised in neuropathological states associated with an increased caspase activation, thereby further adding to the cellular stress. 相似文献