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81.
Gastrodia anti-fungal protein (GAFP) displays strong inhibitory activity against certain fungal pathogens. Five GAFP analogues with different mutations at mannose-binding sites and the wild-type one were expressed and purified in Escherichia coli. The inhibitory analysis of the purified various GAFPs against the growth of Trichoderma viride indicates that single amino acid mutated-type GAFPs have inhibitory activity, but its activity is much less than the wild-type one. The double and triplicate amino acids mutated GAFPs have very low inhibitory activity. For the first time it was proved that GAFP mannose-binding sites play key role in anti-fungi process. 相似文献
82.
The adhesive polyphenolic proteins from Aulacomya ater and Choromytilus chorus with apparent molecular masses of 135000 and 105000, respectively, were digested with trypsin and the peptides produced resolved by reversed phase liquid chromatography. About 5 and 12 major peptides were obtained from the protein of A. ater and C. chorus, respectively. The major peptides were purified by reverse-phase chromatography and the amino acid sequence indicates that both polyphenolic proteins consisted of repeated sequence motifs in their primary structure. The major peptides of A. ater contain seven amino acids corresponding to the consensus sequence AGYGGXK, whereas the tyrosine was always found as 3, 4-dihydroxyphenylalanine (Dopa), the X residue in position 6 was either valine, leucine or isoleucine, and the carboxy terminal was either lysine or hydroxylysine. On the other hand, the major peptides of C. chorus ranged in size from 6 to 21 amino acids and the majority correspond to the consensus sequence AKPSKYPTGYKPPVK. Both proteins differ markedly in the sequence of their tryptic peptides, but they share the common characteristics of other adhesive proteins in having a tandem sequence repeat in their primary structure. 相似文献
83.
Thirty-one Listeria strains were tested for sensitivity to four class IIa bacteriocins, namely, enterocin A, mesentericin Y105, divercin V41,
and pediocin AcH, and to nisin A. Class IIa bacteriocins displayed surprisingly similar antimicrobial patterns ranging from
highly susceptible to fully resistant strains, whereas nisin A showed a different pattern in which all Listeria strains were inhibited. Particularly, it was observed that the strain Listeria monocytogenes V7 could not be inhibited by any of the class IIa bacteriocins tested. These observations suggest that Listeria strains resistant to the whole range of class IIa bacteriocins may occur in natural environments, which could be of great
concern with regard to the use of these peptides as food preservatives.
Received: 22 October 1999 / Accepted: 15 December 1999 相似文献
84.
A new group of cytokins, having the properties of chemoattractants and named "chemokins", has been characterized. These structurally related low-molecular proteins (8-10 kD) with 20-90% homology in amino acids contain 4 conservative disulfide-linked cysteins whose location determines which of the groups (CXC, CC, C) they belong to. Chemokins regulate the migratory activity of all types of leukocytic cells. Target cells are affected by chemokins through specific receptors (at least 9 types) of the rhodopsin family, including 7 transmembrane domains. Chemokins play an important role in the pathogenesis of many diseases, especially those of inflammatory nature. Some chemokins (RANTES, MIP-1) and their receptors are linked with the development of HIV infection. Chemokins serve as the basis of medicinal preparations, blocking or enhancing the migratory activity of leukocytes. Our newly developed preparation, based on a complex of natural cytokins, induces, when used locally, the influx of neutrophils and macrophages to the zone of tissue destruction, acting as chemokins. 相似文献
85.
Tobaly-Tapiero J Bittoun P Neves M Guillemin MC Lecellier CH Puvion-Dutilleul F Gicquel B Zientara S Giron ML de Thé H Saïb A 《Journal of virology》2000,74(9):4064-4073
Foamy viruses (FVs) are complex retroviruses which have been isolated from different animal species including nonhuman primates, cattle, and cats. Here, we report the isolation and characterization of a new FV isolated from blood samples of horses. Similar to other FVs, the equine foamy virus (EFV) exhibits a highly characteristic ultrastructure and induces syncytium formation and subsequent cell lysis on a large number of cell lines. Molecular cloning of EFV reveals that the general organization is that of other known FVs, whereas sequence similarity with its bovine FV counterpart is only 40%. Interestingly, EFV buds exclusively from the plasma membrane and not from the endoplasmic reticulum (ER), as previously shown for other FVs. The absence of the ER retrieval dilysine motif in EFV Env is likely responsible for this unexpected sorting pathway. 相似文献
86.
87.
Improved tests for heterogeneity across a region of DNA sequence in the ratio of polymorphism to divergence 总被引:15,自引:9,他引:6
The neutral theory of molecular evolution predicts that the ratio of
polymorphisms to fixed differences should be fairly uniform across a region
of DNA sequence. Significant heterogeneity in this ratio can indicate the
effects of balancing selection, selective sweeps, mildly deleterious
mutations, or background selection. Comparing an observed heterogeneity
statistic with simulations of the heterogeneity resulting from random
phylogenetic and sampling variation provides a test of the statistical
significance of the observed pattern. When simulated data sets containing
heterogeneity in the polymorphism-to-divergence ratio are examined,
different statistics are most powerful for detecting different patterns of
heterogeneity. The number of runs is most powerful for detecting patterns
containing several peaks of polymorphism; the Kolmogorov-Smirnov statistic
is most powerful for detecting patterns in which one end of the gene has
high polymorphism and the other end has low polymorphism; and a newly
developed statistic, the mean sliding G statistic, is most powerful for
detecting patterns containing one or two peaks of polymorphism with reduced
polymorphism on either side. Nine out of 27 genes from the Drosophila
melanogaster subgroup exhibit heterogeneity that is significant under at
least one of these three tests, with five of the nine remaining significant
after a correction for multiple comparisons, suggesting that detectable
evidence for the effects of some kind of selection is fairly common.
相似文献
88.
89.
Gülay Bayramoğlu Meral Karakışla Begum Altıntaş Ayşegül U. Metin Mehmet Saçak M. Yakup Arıca 《Process Biochemistry》2009,44(8):880-885
Polyacylonitrile fibers (PAN) surfaces were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The effect of aniline concentration on the grafting efficiency and on the electrical surface resistance of PAN/PANI composite fibers was investigated. The surface resistance of the conductive composite fibers in this work was found to be between 8.0 and 0.5 kΩ/cm. As the amount of grafted PANI increased on the PAN fibers the electrical resistance of composite fibers decreased. The PAN/PANI composite fibers were characterized by SEM and FTIR studies. Composite PAN/PANI fibers were used for reversible immobilization of invertase. The immobilization efficiency and the activity of the immobilized invertase (from 1.0 mg/mL invertase solution at pH 5.5) were increased with increasing PANI contents of the composite fibers. The maximum amount of immobilized enzyme onto composite fibers containing 2.0% PANI was about 76.6 mg/g. The optimum pH for the free enzyme was observed at 5.0. On the other hand, immobilized invertase yielded a broad optimum pH profile between pH 5.0 and 7.0. Immobilized invertase exhibited 83% of its original activity even after two months storage at 4 °C while the free enzyme showed only 7% of its initial activity. 相似文献
90.
Stéphanie Foulon Tim Greacen Blandine Pasquet Romain Dugravier Thomas Sa?as Nicole Guedeney Antoine Guedeney Florence Tubach CAPEDP Study Group 《PloS one》2015,10(11)