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1.
Ramesh Chand Manoj Kumar Chanda Kushwaha Kavita Shah Arun K. Joshi 《Current microbiology》2014,69(2):202-211
Eighteen barley isolates of Bipolaris sorokiniana belonging to wild and clonal type of black, mixed and white subpopulations were quantitatively assayed for their melanin content and aggressiveness with respect to production of some of the extracellular enzymes such as cellulase, pectinase, amylase and protease. Cellulase and pectinase constituted major portion of the enzymes recovered from the black, mixed and white isolates. Enzyme production and aggressiveness were relatively higher in melanin devoid or low melanin isolates. The melanin deficient isolates were also differentiated from black and mixed isolates on the basis of variation in internal transcribed spacer region of the ribosomal DNA. Higher enzyme productions positively correlated with area under disease progress curve (AUDPC) and lesion development. Melanin content was negatively correlated with extracellular enzymes and aggressiveness of the isolates. Based on melanin content, lesion size, AUDPC and extracellular enzymes, the isolates were grouped in two major clusters (I and II) with further division of cluster II into two sub-clusters (II-A and II-B). The results appears to indicate a possible role of melanin in release of extracellular enzymes and hence in evolution and selection of aggressive isolates of B. sorokiniana in barley. 相似文献
2.
Vasant Chellappa Kendra N. Taylor Kathryn Pedrick Carlos Donado Ilka Arun Netravali Khaleda Haider Annaiah Cariappa Natasha F. Dalomba Shiv Pillai 《PloS one》2013,8(1)
Catalytically defective rare variants of Sialic acid Acetyl Esterase (SIAE) have previously been linked to autoimmunity. Studies presented here confirm that the M89V SIAE protein and all other products of common variant alleles of SIAE are catalytically normal. Although overexpressing transfected non-lymphoid cells secrete small amounts of SIAE that can associate with the cell surface, normal human lymphocytes do not exhibit cell surface SIAE, supporting genetic evidence in mice that indicates that this protein functions in a lymphocyte intrinsic manner. Analyses of the plasma proteome also indicate that SIAE is not secreted in vivo. A re-analysis exclusively of catalytically defective rare variant alleles of SIAE in subjects in which this gene was completely sequenced confirmed an association of SIAE with autoimmunity. A subset of catalytically defective rare variant SIAE alleles has previously been typed in a large genotyping study comparing a diverse group of disease subjects and controls; our re-analysis of this data shows that catalytically defective alleles are enriched in disease subjects. These data suggest that SIAE may be associated with autoimmunity and that further study of catalytically defective rare variant SIAE alleles in terms of autoimmune disease susceptibility is strongly warranted. 相似文献
3.
4.
Bryan D. Noe Sharon L. Milgram A. Balasubramaniam P. C. Andrews Jaroslaw Calka John K. McDonald 《Cell and tissue research》1989,257(2):303-311
Summary Results from a previous report demonstrate that more than one molecular form of neuropeptide Y-like peptide may be present in the islet organ of the anglerfish (Lophius americanus). Most of the neuropeptide Y-like immunoreactive material was anglerfish peptide YG, which is expressed in a subset of islet cells, whereas an additional neuropeptide Y-like peptide(s) was localized in islet nerves. To learn more about the neuropeptide Y-like peptides in islet nerves, we have employed immunohistochemical and biochemical methods to compare peptides found in anglerfish islets and brain. Using antisera that selectively react with either mammalian forms of neuropeptide Y or with anglerfish peptide YG, subsets of neurons were found in the brain that labelled with only one or the other of the antisera. In separate sections, other neurons that were labelled with either antiserum exhibited similar morphologies. Peptides from brains and islets were subjected to gel filtration and reverse-phase high performance liquid chromatography. Radioimmunoassays employing either the neuropeptide Y or peptide YG antisera were used to examine chromatographic eluates. Immunoreactive peptides having retention times of human neuropeptide Y and porcine neuropeptide Y were identified in extracts of both brain and islets. This indicates that peptides structurally similar to both of these peptides from the neuropeptide Y-pancreatic polypeptide family are expressed in neurons of anglerfish brain and nerve fibers of anglerfish islets. The predominant form of neuropeptide Y-like peptide in islets was anglerfish peptide YG. Neuropeptide Y-immunoreactive peptides from islet extracts that had chromatographic retention times identical to human neuropeptide Y and porcine neuropeptide Y were present in much smaller quantities. These results are consistent with the hypothesis that peptides having significant sequence homology with human neuropeptide Y and porcine neuropeptide Y are present in the nerve fibers that permeate the islet. 相似文献
5.
The intracellular pH of the halotolerant green algae Dunaliella tertiolecta, was determined by the distribution of 5,5-dimethyl-2(14C)-oxalolidine-2,5-dione (DMO) between the cell and the surrounding medium. 5,5-dimethyl-2(14C)oxalolidine-2,4-dione was not metabolized by the algal cells. The intracellular pH of Dunaliella tertiolecta was 6.8 in the dark and 7.4 in the light. During a salt stress, after two hours, the intracellular pH was increased by 0.2 pH units in both light and dark. The salt stressed cells maintained a constant pH of about 7.5 over the pH range of 6.5 to 8.5. Because of the relatively low permeability coefficient of the plasma membrane for DMO, this technique does not permit rapid pH determinations during the induction period after a salt stress. The magnitude of the salt induced pH changes measured 2 h after the salt stress implies a minor importance of this alkalization in this time range, but does not exclude a larger importance of pH changes for osmoregulation during the induction period.Abbreviations Chl
chlorophyll
- DMO
5,5-dimethyl-2(14C)oxalolidine-2,4-dione
- PCV
packed cell volume
- SDS
sodium dodecyl sulfate 相似文献
6.
A Balasubramaniam V Renugopalakrishnan D F Rigel M S Nussbaum R S Rapaka J C Dobbs L A Carreira J E Fischer 《Biochimica et biophysica acta》1989,997(3):176-181
Neuropeptide Y (NPY) is a 36 amino acid peptide amide isolated from porcine brain. The NPY analog, 4-norleucine-NPY was synthesized by a solid-phase method and purified to homogeneity in 20% yield by reverse-phase chromatography. Investigation of the biological properties indicated that the analog is an agonist of NPY. Secondary structural analyses revealed that NPY and the analog exhibited predominantly alpha-helical and beta-sheet structures, respectively; however, experiments in trifluoroethanol indicated that the analog has the potential of assuming an alpha-helical structure. Based on circular dichroism (CD), Raman spectroscopy and Chou-Fasman analyses, a model has been proposed for the secondary structure of NPY. 相似文献
7.
Ravindra K. Malhotra Sanjiv V. Bhave Taruna D. Wakade Arun R. Wakade 《Journal of neurochemistry》1988,51(3):967-974
The effects of phorbol esters [phorbol 12,13-dibutyrate (PDB), 12-O-tetradecanoylphorbol 13-acetate (TPA), and phorbol 13-acetate] were investigated on the release of [3H]norepinephrine, 45Ca2+ accumulation, and protein kinase C activity in cultured sympathetic neurons of the chick embryo. Sympathetic neurons derived from 10-day-old chick embryo were cultured in serum-free medium supplemented with insulin, transferrin, and nerve growth factor. After 3 days, neurons were loaded with [3H]-norepinephrine and the release of [3H]norepinephrine was determined before and after electrical stimulation. Stimulation at 1 Hz for 15 s increased the release of [3H]-norepinephrine over the nonstimulation period. Stimulation-evoked release gradually declined with time during subsequent stimulation periods. Incubation of neurons in Ca2+-free Krebs solution containing 1 mM EGTA completely blocked stimulation-evoked release of [3H]-norepinephrine. Stimulation-evoked release of [3H]-norepinephrine was markedly facilitated by 3 and 10 nM PDB or TPA. The spontaneous release was also enhanced by PDB and TPA. The net accumulation of 45Ca2+ during stimulation of sympathetic neurons was increased by two- to fourfold in the presence of PDB or TPA. PDB at 1-100 nM produced a concentration-dependent increase in the activation of protein kinase C. PDB at 30 nM increased the activity of protein kinase C of the particulate fraction from 0.09 to 0.58 pmol/min/mg protein. There was no significant change in protein kinase C activity of the cytosolic fraction (0.14 pmol/min/mg versus 0.13 pmol/min/mg protein). The ratio of the particulate to cytosolic protein kinase C increased from a control value of 0.62 to 4.39 after treatment with 30 nM PDB. TPA (10 and 30 nM) also increased protein kinase C activity of the particulate fraction by six- to eightfold. Phorbol 13-acetate had no effect on protein kinase C activity, [3H]norepinephrine release, and 45Ca2+ accumulation. These results provide direct evidence that activation of protein kinase C enhances Ca2+ accumulation, which in turn leads to the facilitation of transmitter release in sympathetic neurons. 相似文献
8.
Substitution of Ser61----Gly61 in human apolipoprotein C-II does not alter its activation of lipoprotein lipase 总被引:1,自引:0,他引:1
A Balasubramaniam R A Demel R F Murphy J T Sparrow R L Jackson 《Chemistry and physics of lipids》1986,39(4):341-346
Lipoprotein lipase (LpL) activity is enhanced by apolipoprotein C-II (apoC-II), a 79 amino acid residue peptide. The minimal apoC-II sequence required for activation of LpL resides between residues 56-79. To determine the possible role of an acyl-apoC-II intermediate involving Ser61 in enzyme catalysis, a synthetic peptide of apoC-II containing residues 56-79 was synthesized and compared to the corresponding peptide with serine at position 61 being substituted with glycine. With two different LpL assay systems, both peptides enhanced enzyme activity. Since glycine does not contain a hydroxyl group, these results rule out the possibility that an acyl-apoC-II intermediate with Ser61 is required for enzyme activation. 相似文献
9.
10.