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171.
The 67-kDa laminin receptor originated from a ribosomal protein that acquired a dual function during evolution 总被引:8,自引:0,他引:8
Ardini E; Pesole G; Tagliabue E; Magnifico A; Castronovo V; Sobel ME; Colnaghi MI; Menard S 《Molecular biology and evolution》1998,15(8):1017-1025
The 67-kDa laminin receptor (67LR) is a nonintegrin cell surface receptor
that mediates high-affinity interactions between cells and laminin.
Overexpression of this protein in tumor cells has been related to tumor
invasion and metastasis. Thus far, only a full-length gene encoding a
37-kDa precursor protein (37LRP) has been isolated. The finding that the
cDNA for the 37LRP is virtually identical to a cDNA encoding the ribosomal
protein p40 has suggested that 37LRP is actually a component of the
translational machinery, with no laminin-binding activity. On the other
hand, a peptide of 20 amino acids deduced from the sequence of 37LR/p40 was
shown to exhibit high laminin-binding activity. The evolutionary
relationship between 23 sequences of 37LRP/p40 proteins was analyzed. This
phylogenetic analysis indicated that all of the protein sequences derive
from orthologous genes and that the 37LRP is indeed a ribosomal protein
that acquired the novel function of laminin receptor during evolution. The
evolutionary analysis of the sequence identified as the laminin-binding
site in the human protein suggested that the acquisition of the
laminin-binding capability is linked to the palindromic sequence LMWWML,
which appeared during evolution concomitantly with laminin.
相似文献
172.
1. Antlions are opportunistic trap building predators that cannot control prey encounter. Their trap should ideally retain a great diversity of prey. However, building a single trap that captures many prey with varying characteristics can be challenging. 2. A series of five different ant species ranging from thin to large, of sizes ranging from 2.75 to 6.5 mm, and a mean weight ranging from 0.54 to 6.00 mg were offered in a random succession to antlions. The state of satiation of the antlions was controlled, and their mass and the depth of their pit were recorded. The reaction of antlion to the prey, the probability of capture as well as the time to escape were recorded. 3. The probability of an antlion reaction is an increasing function of the pit depth and a decreasing function of antlion mass. The probability of capture is highest for intermediate prey mass and is an increasing function of pit depth. The time to escape is a declining function of prey mass and an increasing function of pit depth. 4. There is an upper limit to prey mass given that large prey escape out of the pit. There is a lower limit to prey mass given the difficulty to apprehend the smallest, thin species. Consequently, there is a range of prey mass, corresponding to a medium‐sized ant of 2 mg, for which the pit functions best. The physics of insect locomotion on sandy slopes was identified as the key to understanding the functioning of antlion pits. 相似文献
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176.
E.K. Khandogina G.R. Mutovin S.V. Zvereva A.V. Antipov D.O. Zverev A.P. Akifyev 《Mutation research》1991,251(2):181-186
The adaptive response (AR) in human lymphocytes in different experimental protocols was investigated. The AR was found to be present in cells pre-exposed to 3 cGy of X-rays in G0, G1 and S phase as well as with tritiated water (4 muCi/ml) when the 'challenge' dose was given in G2. There was no AR after prior exposure of the cells in S phase to secondary irradiation from 70 GeV protons. The AR was not observed after preliminary X-irradiation of the lymphocytes in G0 and G1 and 'challenge' irradiation in G1. Cells from 6 patients with Down's syndrome were tested. At least 5 of them did not show the AR. The AR is considered to be a phenomenon of the antimutagenic aftereffect. 相似文献
177.
GUOWEI LI MARIE BOUDSOCQ SONIA HEM JÉRÔME VIALARET MICHEL ROSSIGNOL CHRISTOPHE MAUREL VÉRONIQUE SANTONI 《Plant, cell & environment》2015,38(7):1312-1320
The hydraulic conductivity of plant roots (Lpr) is determined in large part by the activity of aquaporins. Mechanisms occurring at the post‐translational level, in particular phosphorylation of aquaporins of the plasma membrane intrinsic protein 2 (PIP2) subfamily, are thought to be of critical importance for regulating root water transport. However, knowledge of protein kinases and phosphatases acting on aquaporin function is still scarce. In the present work, we investigated the Lpr of knockout Arabidopsis plants for four Ca2+‐dependent protein kinases. cpk7 plants showed a 30% increase in Lpr because of a higher aquaporin activity. A quantitative proteomic analysis of wild‐type and cpk7 plants revealed that PIP gene expression and PIP protein quantity were not correlated and that CPK7 has no effect on PIP2 phosphorylation. In contrast, CPK7 exerts a negative control on the cellular abundance of PIP1s, which likely accounts for the higher Lpr of cpk7. In addition, this study revealed that the cellular amount of a few additional proteins including membrane transporters is controlled by CPK7. The overall work provides evidence for CPK7‐dependent stability of specific membrane proteins. 相似文献
178.
Factors shaping latitudinal patterns in communities of arboreal spiders in northern Europe
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Mikhail V. Kozlov Marzena Stańska Izabela Hajdamowicz Vitali Zverev Elena L. Zvereva 《Ecography》2015,38(10):1026-1035
Predator effects on herbivores are often referred to as examples of biotic interactions that weaken with latitude, but more studies are needed to test for the generality of this pattern. To further the understanding of large‐scale geographical patterns in abundance and diversity of predatory arthropods, from 2008–2011 we explored spider communities in the canopies of primary forest trees of the boreal zone (Pinus sylvestris, Picea abies, Betula pubescens and B. pendula) along five latitudinal gradients in northern Europe, from 59 to 70°N and from 10 to 60°E. The abundance of arboreal spiders in Norway and Finland was about a half of that in Russia, presumably due to more intensive forest management in Scandinavia. The abundance, taxonomic and functional diversity of arboreal spiders generally decreased with latitude; however, actual weather conditions during the study years had little effect on this pattern. Coniferous species supported higher abundance and diversity of arboreal spiders than birches, but the poleward decrease in either abundance or taxonomic diversity of arboreal spiders did not differ between coniferous and deciduous tree species. In contrast, functional diversity on birches decreased with latitude greater than on coniferous trees. Euryphagous spiders showed stronger decrease with latitude in terms of both abundance and taxonomic diversity than more specialized (steno‐ and oligophagous) spiders. We attribute the general decrease in density and diversity of spiders with latitude to an increased pressure from apex predators (birds) rather than to direct effects of climate or changes in prey abundance. The abundance of spiders declined with the latitude to the greater extent than the densities of their potential prey did, suggesting a decrease in the strength of predator–prey interactions towards the north. 相似文献
179.
Sathiyamoorthy Meiyalaghan Philippa J Barrell Jeanne ME Jacobs Anthony J Conner 《BMC biotechnology》2011,11(1):1-10
Background
Tools for authenticating cell lines are critical for quality control in cell-based biological experiments. Currently there are methods to authenticate human cell lines using short tandem repeat (STR) markers based on the technology and procedures successfully used in the forensic community for human identification, but there are no STR based methods for authenticating nonhuman cell lines to date. There is significant homology between the human and vervet monkey genome and we utilized these similarities to design the first multiplex assay based on human STR markers for vervet cell line identification.Results
The following STR markers were incorporated into the vervet multiplex PCR assay: D17S1304, D5S1467, D19S245, D1S518, D8S1106, D4S2408, D6S1017, and DYS389. The eight markers were successful in uniquely identifying sixty-two vervet monkey DNA samples and confirmed that Vero76 cells and COS-7 cells were derived from Vero and CV-1 cells, respectively. The multiplex assay shows specificity for vervet DNA within the determined allele range for vervet monkeys; however, the primers will also amplify human DNA for each marker resulting in amplicons outside the vervet allele range in several of the loci. The STR markers showed genetic stability in over sixty-nine passages of Vero cells, suggesting low mutation rates in the targeted STR sequences in the Vero cell line.Conclusions
A functional vervet multiplex assay consisting of eight human STR markers with heterozygosity values ranging from 0.53-0.79 was successful in uniquely identifying sixty-two vervet monkey samples. The probability of a random match using these eight markers between any two vervet samples is approximately 1 in 1.9 million. While authenticating a vervet cell line, the multiplex assay may also be a useful indicator for human cell line contamination since the assay is based on human STR markers. 相似文献180.
以金属框架结构材料MOF-199为载体对漆酶进行固定化,并对固定化酶的性质进行初步研究。首先,以3-氨基丙基三乙氧基硅烷对载体MOF-199进行表面氨基化修饰,再用戊二醛对载体进行活化,最后对漆酶进行固定化。固定化条件优化结果表明:在漆酶质量浓度0.3 g/L,戊二醛用量1%(体积分数),pH 4.8下固定7 h,制得固定化酶活性最高。对固定化酶的研究发现:最适反应温度为40℃,最适pH为5.2,在连续操作7次后,固定化酶的活力仍能保持在51%。固定化漆酶热稳定性,pH耐受性,贮存稳定性均明显高于游离漆酶。 相似文献