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101.
A.E.G. Cass 《Journal of inorganic biochemistry》1981,15(4):359-362
An ultrafiltration technique was used to study stripping by glycine of the first copper and zinc ion equivalents bound by bovine, dog, and rat serum albumins at pH 7.5. Affinity of dog serum albumin for copper was poorer than for the other albumins, consistent with the absence in the former albumin of the copper binding site present at the amino terminus of the latter albumins. Affinities of all three proteins for zinc were similar, suggesting that the albumin amino terminus is not the primary zinc ion binding site. 相似文献
102.
The heme iron of the β chains of mammalian hemoglobins are rapidly and selectively oxidized in the presence of excess Cu(II) ions in a reaction that requires the presence of a free -SH groups on the β globin chain. The presence of freely reactive -SH groups on the α chains of cat and sheep hemoglobins does not alter the course of this reaction: only the β hemes are oxidized rapidly by Cu(II) in these hemoglobins. Two equivalents of copper are required for the rapid oxidation of the two β chain hemes per mole of cat hemoglobin, in contrast with the four equivalents that are required for reaction with human hemoglobin. The human-cat hybrid hemoglobins, α2Humanβ2Cat and α2Catβ2Human, required two and four equivalents of copper/mol, respectively, for the reaction. Thus, the kinetics and stoichimetry of the reaction are determined by the nature of the β subunit. Analysis of the esr spectra of the products of the reaction of Cu(II) with these hemoglobins indicate that human hemoglobin and the hybrid α2Catβ2Human contain tight binding sites for two equivalents of Cu(II) that are not involved in the oxidation reaction and are not present in cat hemoglobin or α2Humanβ2Cat. Cat β globin like others (sheep, bovine) that lack the tight binding site, has no histidine residue at 2β. It has phenylalanine in this position. These results support the suggestion of Rifkind et al. (Biochemistry 15,5337[1976]) that the tight binding site is near the amino terminal region of the β chain and is associated with histidine 2β. 相似文献
103.
Ontogeny of human Ia antigens 总被引:1,自引:0,他引:1
P G Natali C Russo A K Ng M R Nicotra C Apollonj M A Pellegrino S Ferrone 《Cellular immunology》1982,73(2):385-396
Indirect immunofluorescence (IIP) staining of tissues from human fetuses (ages ranging from 8 to 32 weeks of intrauterine life) with monoclonal antibodies (MoAb) to monomorphic determinants of Ia antigens and HLA-A,B,C antigens has shown that both types of antigens are already detectable in tissues of 8-week-old fetuses. Ia antigens and HLA-A,B,C antigens reach their almost-complete tissue distribution after 32 and 24 weeks of intrauterine life, respectively. The structure of Ia antigens synthesized by fetal thymus cells is similar to that of B-lymphoid cell-derived Ia antigens. Ia antigen-bearing thymic fetal cells can stimulate allogeneic lymphocytes in mixed lymphocyte reactions (MLRs). These reactions are blocked by monoclonal antibodies to monomorphic determinants of human Ia antigens and of HLA-A,B, antigens. 相似文献
104.
105.
Two dimensional tryptic peptide maps have been obtained from 2 μg (40 pmol) of protein digest following labeling with 3H or 14C via reductive methylation. A simple labeling procedure is complete within 1 h; autoradiographs of 14C-labeled maps and fluorographs of 3H-labeled maps are obtained in 72 and 24 h, respectively. Tryptic peptide maps of methylated α- and β-tubulin, and rabbit muscle, chick muscle, and chick brain actins show approximately the expected number of peptides. Methylation does not appear to measurably alter the map positions of the peptides relative to unmethylated peptides in the solvent systems used for either electrophoresis or chromatography. 相似文献
106.
Cary A. Presant David Carr 《Biochemical and biophysical research communications》1980,93(4):1067-1073
In HT29 human colon carcinoma cells, amphotericin B at doses above 120μg/ml increased nitrogen mustard uptake, and this was due to an increase in the apparent Vmax without a change in the apparent Km. Longer incubations (24 to 48 hr) of ascites fluid human ovarian carcinoma cells or SKMES-1 human epidermoid carcinoma cells with amphotericin B 4μg/ml enhanced the uptake of nitrogen mustard to a greater degree than that observed when cells were incubated for only 30 min. Therefore, amphotericin B can enhance nitrogen mustard by human tumor cell lines and by fresh human tumor cells. 相似文献
107.
Jean-Claude Moulin Jérémy Silvano Véronique Barban Patrice Riou Caroline Allain 《Biologicals》2013,41(4):238-246
The neurovirulence of two new candidate 17D-204 Stamaril? working seed lots and that of two reference preparations were compared. The Stamaril? working seed lots have been used for more than twenty years for the manufacturing of vaccines of acceptable safety and efficacy. The preparation designated RK 168-73 and provided by the Robert Koch Institute was used as a reference. It was confirmed that RK 168-73 strain was not a good virus control in our study because it has a very low neurovirulence regarding both the clinical and histopathological scores in comparison with Stamaril? strain and is not representative of a vaccine known to be satisfactory in use. The results were reinforced by the phenotypic characterization by plaque assay demonstrating that RK 168-73 was very different from the Stamaril? vaccine, and by sequencing results showing 4 mutations between Stamaril? and RK 168-73 viruses leading to amino acid differences in the NS4B and envelop proteins. 相似文献
108.
Impact of road construction on giant panda’s habitat and its carrying capacity in Qinling Mountains
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The Qinling giant panda (Ailuropoda melanoleuca) is an endangered endemic species to China. Despite ongoing efforts to ensure its conservation, concerns about maintaining its populations persist. We used GIS fed with data on land use including road network of 2001, third national giant panda survey, and a digital elevation model (DEM) to assess the impact of road construction on giant panda habitat, and estimate the carrying capacity of the Qinling Mountain area. We assessed habitat suitability with a mechanistic model, and conducted correlation analysis to evaluate relationship between the extent of giant panda habitat and amount of sites occupied by pandas within of 5 km × 5 km grid. We also estimated the carrying capacity of the Qinling Mountainous Area.
Our results revealed a significant correlation (R2 = 0.447, P < 0.01) between the number of sites with signs left by giant panda and the extent of habitat within of 5 km × 5 km grid. The minimum habitat area that can support one panda was 10 km2. Before the road network construction, the area of habitat suitable for the panda amounted about 1561 km2 and that of marginally suitable habitat about 1499 km2. The corresponding carrying capacity represented about 240 individuals. After the road network construction, the suitable habitat area was reduced by nearly 30% to 1093 km2. Marginally suitable habitat and unsuitable habitat have both increased by 17% and 1%, respectively. As a result, the potential population size which the habitat could support was reduced to 217 individuals. The study results also suggested that most impacts on habitat from road construction took place in the high elevation areas above 1500 m. However, regarding the impact on the giant panda habitat, road networks developed much more inside the current nature reserves than outside of them. 相似文献
Our results revealed a significant correlation (R2 = 0.447, P < 0.01) between the number of sites with signs left by giant panda and the extent of habitat within of 5 km × 5 km grid. The minimum habitat area that can support one panda was 10 km2. Before the road network construction, the area of habitat suitable for the panda amounted about 1561 km2 and that of marginally suitable habitat about 1499 km2. The corresponding carrying capacity represented about 240 individuals. After the road network construction, the suitable habitat area was reduced by nearly 30% to 1093 km2. Marginally suitable habitat and unsuitable habitat have both increased by 17% and 1%, respectively. As a result, the potential population size which the habitat could support was reduced to 217 individuals. The study results also suggested that most impacts on habitat from road construction took place in the high elevation areas above 1500 m. However, regarding the impact on the giant panda habitat, road networks developed much more inside the current nature reserves than outside of them. 相似文献
109.
哈萨克斯坦位于欧亚大陆腹地, 地处丝绸之路经济带的重要位置。中国与哈萨克斯坦开展生物多样性保护合作, 有助于解决地区生态环境问题和推动“一带一路”倡议的顺利实施。目前国内尚缺乏对哈萨克斯坦生物多样性及其保护状况的了解。本文在文献的基础上通过定量和定性分析方法, 从地理环境特征、生物多样性状况、保护成效和需求等维度对哈萨克斯坦生物多样性及其保护的总体情况进行了分析。分析结果表明, 哈萨克斯坦的生物多样性丰富, 但也存在着较严重的丧失问题; 哈萨克斯坦政府重视生物多样性保护, 积极承担相关国际履约义务; 在保护管理方面实行多级管理体制, 并与社会经济发展需求相结合, 取得了一定成效。 相似文献
110.
缅甸是中国"一带一路"倡议向南开放、开展区域合作的重要门户。缅甸药用生物资源丰富,其传统医药已有两千年使用历史。中缅医药文化的共通性、药材资源和消费市场的互补性使两国传统医药贸易与合作研发潜力巨大,两国传统医药合作可作为"一带一路"实施的良好媒介和载体。本文简要概述了缅甸传统药物应用及研发情况,"一带一路"背景下两国开展传统医药合作的必要性及两国传统医药交流与合作近况,并对当前可开展合作研发的领域进行了分析。两国传统药物合作将能有效促进两国生物资源可持续利用及传统医药技术和资源的优势互补与共享。 相似文献