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121.
K. T. Bird T. C. Chiles R. E. Longley A. F. Kendrick M. D. Kinkema 《Journal of applied phycology》1993,5(2):213-218
Protein extracts from 22 species of marine macroalgae from Florida and North Carolina were compared for their abilities to
agglutinate sheep and rabbit erythrocytes. Protein extracts from 21 algal species agglutinated rabbit erythrocytes compared
to 19 for sheep erythrocytes. However, agglutination by brown algal extracts was variable. The agglutination produced by protein
extracts from Dictyota dichotoma could be blocked by addition of polyvinylpyrrolidone. Protein extracts from North Carolina macroalgae were also tested against
five bacterial species. Three of these agglutinated bacterial cells. Ulva curvata and Bryopsis plumosa agglutinated all five species. Protein extracts from five species of Florida algae were tested for their effects on mitogenesis
in mouse splenocytes and human lymphocytes. Gracilaria tikvahiae HBOI Strain G-5, Ulva rigida and Gracilaria verrucosa HBOI Strain G-16S stimulated mitogenesis in mouse splenocytes, while Gracilaria tikvahiae HBOI Strain G-16stimulated mitogenesis in human lymphocytes. 相似文献
122.
Lectins that interact with mannose (concanavalin A), galactose (ricin, abrin), or N-acetylglucosamine (wheat germ agglutinin) block 125I-labeled EGF binding to the surface of cultured human fibroblasts at 37° or 5°. Lectins specific for fucose or N-acetylgalactosamine, soybean agglutinin or gorse lectin, respectively, do not interfere with growth factor binding. The inhibition of 125I-labeled EGF binding by concanavalin A at 37° or 5° could be reversed rapidly by the addition of α-methyl mannoside. The results suggest that the fibroblast membrane receptor for EGF is, or is closely associated with, a glycoprotein or glycolipid that contains mannose, galactose and N-acetylglucosamine residues. 相似文献
123.
Abstract. The onset of prestalk differentiation of Dictyostelium discoideum has been thought to be triggered by differentiation inducing factor (DIF), which is secreted by differentiating cells. We characterized the cell-type specific proteins, wst31 (prestalk and stalk specific) and wst34 (stalk specific), using the mutant HM44 which is defective in DIF-production, and examined the effects of DIF and cAMP on the formation of the proteins. In the mutant HM44, wst34 was formed only in the presence of exogenous DIF as reported for other prestalk/stalk markers (e.g. pDd63 and acid phosphatase-2), which indicates the DIF-requirement for this protein. By contrast, the accumulation of wst31 in this mutant occurred in the presence of cAMP regardless of the presence of exogenous DIF. Thus, we propose a new and distinct state (or stage) in prestalk differentiation, where the expression of wst31 occurs but not that of pDd63 or acid phosphatase-2. 相似文献
124.
Summary The in vivo effects of tunicamycin on the glycosylation of proteoglycans and link protein in rat mandibular condylar chondrocytes were studied by ultrastructural lectin histochemistry. The binding of wheatgerm agglutinin was shown by using anti-lectin antibody followed by protein A-gold complex. In normal rats, wheat-germ agglutinin labeling was restricted to trans cisternae and vacuoles of the Golgi complex, whereas it was observed in neither the cis region of the Golgi complex nor in the rough endoplasmic reticulum. By 3 h after the drug administration, wheat-germ agglutinin binding sites on the disorganized Golgi vacuoles were dramatically reduced in number. At 6 h after the drug administration, the lectin binding sites on the Golgi vacuoles were restored. These results demonstrate that the in vivo use of tunicamycin in combination with histochemical analysis using lectin probes is of significant value for the study of protein glycosylation in chondrocytes of the rat mandibular condyle. 相似文献
125.
Teguments from spargana of Spirometra mansonoides were disrupted and removed using 0.2% Triton ×-100. Tegumental fractions were obtained by differential centrifugation and the proteins and glycoproteins of this surface layer were partially characterized in 9 to 20% linear gradient sodium dodecyl sulfate-polyacrylamide slab gels. Electrophoretic analysis of the microtriches (brush border) and vesicular fractions revealed nine polypeptides that were common to these tegumental fractions. The polypeptide composition of the microtriches and vesicular fractions differed qualitatively and with respect to the relative concentrations of certain polypeptides. Glycopeptides of the microtriches and vesicular fractions were identified by the direct application of the following fluorescein isothiocyanate-conjugated lectins to slab gels: concanavalin A, wheat germ agglutinin, Ricinus communis agglutinin-120, soybean agglutinin, and Ulex europaeus agglutinin-1. The major polypeptides associated with the tegument were found to be glycopeptides. U. europaeus agglutinin-1 failed to label any tegumental glycopeptides. Based on the different sugar specificities of the lectins tested, the oligosaccharide chains of tegumental glycoproteins of S. mansonoides may contain the following carbohydrates: d-mannose, d-glucose, N-acetyl-d-glucosamine, N-acetylneuraminic acid, d-galactose, and N-acetyl-d-galactosamine. 相似文献
126.
Formation of Plantlets was achieved when stem apex of Pinellia ternata Brier. Cultured in vitro on MS medium with KT 0. 5 mg/L + NAA 0.2 mg/L (MSI). With petioles of the plantlet as explants callus could be induced after cultured for a week on MS medium with 2, 4-D 2.0 mg/L + KT 0.5 mg/L (MSII). Calli were subcultured once in every month. After 3--4 months a kind of friable calli could be selected, from which the tubercles could be differentiate and the plantlets formed when transfered onto MSI. But before callus differentiation, a lot of roots were formed on callus. The plantlets could be produced directly from the petiole segment. It was found that the stem growing tip was always covered by the leaf primordium and the former leaf primordium was covered by the latter leaf primordium during the differentiation of the apical bud of tubercle. The frenquency of plantlet differentiation from callus and petioles was over 70%. The rate of regeneration of plantlet on liquid static culture was twice as much as that on solid culture. All plantlets grew well after being transfered into the plot. The fresh weight of tuber-plant was 103 % higher than that of control (cultivated plant come from tubers). The alkaloid content of tubers come from tuberplant was 0. 344%, that of control was 0. 203% and 0. 264% for the wild tuber. 相似文献
127.
Yamaguchi T 《Archives of microbiology》2004,181(2):106-111
Streptococcus intermedius strain 1208-1 cells were aggregated in the presence of saliva. The saliva agglutinin was purified by centrifugation, filtration, and gel filtration. SDS-PAGE analyses indicated that the purified agglutinin consisted of two high-molecular-mass proteins. Aggregation was dependent on calcium over pH 5.5, with 1 mM being the most effective concentration. Boiling inactivated purified agglutinin. S. intermedius strain 3 and Streptococcus mutans strain 1 were aggregated in the purified agglutinin. After adsorption with strain 1208-1 cells, the saliva sample did not exhibit any aggregation activity, and the agglutinin bands were no longer visible by SDS-PAGE. Adherence analyses demonstrated that the purified agglutinin immobilized on the surfaces of polystyrene wells, actinomyces cells, and apatite beads accounted for the binding of streptococcus cells. Agglutinin also effectively inhibited adherence to apatite beads coated with native saliva. 相似文献
128.
In order to enhance the resistance to pests, transgenic maize (Zea mays L.) plants from elite inbred lines containing the gene encoding snowdrop lectin (Galanthus nivalis L. agglutinin; GNA) under control of a phloem-specific promoter were generated through theAgrobacterium tumefaciens- mediated method. The toxicity of GNA-expressing plants to aphids has also been studied. The independently derived plants
were subjected to molecular analyses. Polymerase chain reaction (PCR) and Southern blot analyses confirmed that thegna gene was integrated into maize genome and inherited to the following generations. The typical Mendelian patterns of inheritance
occurred in most cases. The level of GNA expression at 0.13%-0.28% of total soluble protein was observed in different transgenic
plants. The progeny of nine GNA-expressing independent transformants that were derived separately from the elite inbred lines
DH4866, DH9942, and 8902, were selected for examination of resistance to aphids. These plants synthesized GNA at levels above
0.22% total soluble protein, and enhanced resistance to aphids was demonstrated by exposing the plants to corn leaf aphid
(Rhopalosiphum maidis Fitch) under greenhouse conditions. The nymph production was significantly reduced by 46.9% on GNA-expressing plants. Field
evaluation of the transgenic plants supported the results from the inoculation trial. After a series of artificial self-crosses,
some homozygous transgenic maize lines expressing GNA were obtained. In the present study, we have obtained new insect-resistant
maize material for further breeding work. 相似文献
129.
A novel superfamily of guanine nucleotide exchange factors for Rho GTPases includes DOCK180 and zizimin1. The zizimin subfamily includes three genes of which only zizimin1 has been cloned. We report here the cloning of zizimin2, identified in a screen for genes enriched in germinal center B cells. Zizimin2 and zizimin1 have similar primary structures and both proteins bound and activated Cdc42 but not the Cdc42-related proteins TC10 or TCL. Their tissue distributions are distinct, however, with zizimin2 expressed predominantly in lymphocytes and an opposite pattern for zizimin1. Zizimin3 was also analyzed and showed distinct GTPase specificity and tissue distribution. 相似文献
130.
Plant lectins: occurrence,biochemistry, functions and applications 总被引:17,自引:0,他引:17
Growing insights into the many roles of glycoconjugates in biorecognition as ligands for lectins indicates a need to compare plant and animal lectins. Furthermore, the popularity of plant lectins as laboratory tools for glycan detection and characterization is an incentive to start this review with a brief introduction to landmarks in the history of lectinology. Based on carbohydrate recognition by lectins, initially described for concanavalin A in 1936, the chemical nature of the ABH-blood group system was unraveled, which was a key factor in introducing the term lectin in 1954. How these versatile probes are produced in plants and how they are swiftly and efficiently purified are outlined, and insights into the diversity of plant lectin structures are also given. The current status of understanding their functions calls for dividing them into external activities, such as harmful effects on aggressors, and internal roles, for example in the transport and assembly of appropriate ligands, or in the targeting of enzymatic activities. As stated above, attention is given to intriguing parallels in structural/functional aspects of plant and animal lectins as well as to explaining caveats and concerns regarding their application in crop protection or in tumor therapy by immunomodulation. Integrating the research from these two lectin superfamilies, the concepts are discussed on the role of information-bearing glycan epitopes and functional consequences of lectin binding as translation of the sugar code (functional glycomics). 相似文献