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771.
红桂木凝集素的纯化与性质研究 总被引:3,自引:0,他引:3
红桂木(Artocarpuslingnanensis)、俗名胭脂,属桑科桂木属,为亚热带、热带植物.红桂木种子含丰富的红桂木凝集素(Artocarpuslingnanensislectin,ALL),但迄今国内外均未见关于它的报道.我们采用Gal-S... 相似文献
772.
新的豆类凝集素FRIL及其体外维持造血干/祖细胞特性的作用机制 总被引:2,自引:0,他引:2
凝集素是一类蛋白质或糖蛋白。自然界中,很多植物可产生凝集素。植物凝集素在分子间的识别过程中起着重要作用。本文主要就新近发现的豆类凝集素FRIL的生物学特性及体外维持造血干/祖细胞的作用机制进行综述。 相似文献
773.
苦参凝集素蛋白基因的分离克隆 总被引:3,自引:0,他引:3
自苦参(Sophora flavescens Ait.)块根中分离得到一种32kD的凝集素蛋白(SFL),其对兔血及人的4种血型都具有很强的凝集活性,对棉花枯萎病菌(Fusarium vasinfectum Atk.),小麦赤霉病菌(Gibberella saubinetii(Mont)Sacc.)和水稻稻瘟病菌(Pricularia oryzae Cav.)的生长有明显抑制作用,依此凝集素蛋白N端部分氨基酸序列合成引物,通过5',3'-RACE技术,从苦参块根总RNA中克隆到了编码这一凝集素蛋白的全长cDNA序列(已注册GenBank,AF285121) ,根据全长cDAN序列这一cDNA序列编码一个284个氨基酸的前体蛋白,而分离得到的凝集素蛋白为一个254个氨基酸残基的成熟蛋白,在其第182位点含一个N糖基化位点N-L-S。 相似文献
774.
775.
In this publication, we will describe the combination of lectin affinity chromatography with nano high performance liquid chromatography (HPLC) coupled to a linear ion trap Fourier transform mass spectrometer (capillary LC-LTQ/FTMS) to characterize N-linked glycosylation structures in human plasma proteins. We used a well-characterized glycoprotein, tissue plasminogen activator (rt-PA), which is present at low levels in blood, as a standard to determine the dynamic range of this approach. N-linked glycopeptides derived from rt-PA could be characterized at a ratio of 1:200 in human plasma (rtPA: total plasma protein, w/w) by accurate mass measurement in the FTMS and fragmentation (MS(n)) in the linear ion trap. We demonstrated that this platform has the potential to characterize the general N-linked glycosylation structures of abundant glycoproteins present in human plasma without the requirement for antibody-based purification, or additional carbohydrate analytical protocols. This conclusion was supported by the determination of carbohydrate structures for three glycoproteins, IgG, haptoglobin, and alpha-1-acid glycoprotein, at their natural levels in a human plasma sample, but only after the lectin enrichment step. 相似文献
776.
777.
Akihiro Kawakubo Hiroyuki Makino Jun-ichi Ohnishi Hideo Hirohara Kanji Hori 《Journal of applied phycology》1997,9(4):331-338
Aqueous ethanolic extracts from five species of the genus Eucheuma (Rhodophyta) i.e. E. serra, E. amakusaensis, E. cottonii,
E. gelatinae and E. denticulatum, were examined for hemagglutinating activity with vertebrate erythrocytes. All the extracts
tested agglutinated trypsin-treated sheep and rabbit erythrocytes as well as untreated sheep erythrocytes. From the extract
of E. serra, which exhibited the highest activity, a lectin was purified by precipitation with cold ethanol followed by gel
filtration to exhibit a single band on SDS-PAGE. The yield was surprisingly as high as 1000 mg from 100 g powdered alga. The
purified lectin was further separated into two isoforms, designated ESA-1(90 mg) and ESA-2 (890 mg), by ion exchange chromatography.
Both lectins showed a single protein band with the same molecular weight of 29 000 on SDS-PAGE and differed from each other
only in isoelectric point (pI 4.75 for ESA-1 and pI 4.95 for ESA-2). Biochemical studies revealed that both are monomeric
proteins without a carbohydrate moiety. The hemagglutinating activities were stable over a wide pH range and at a relatively
high temperature. The activities were inhibited by a number of glycoproteins, but not by any of the monosaccharides and disaccharides
tested. The lectins showed strong mitogenic activities for mouse lymphocytes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
778.
陈圣敏 《Virologica Sinica》1992,7(2):166-175
应用十二种生物素标记的凝集素,分析了经SDS-PAGE和电转印分离的登革Ⅱ型病毒(D_2V)糖蛋白。结果表明:D_2V的包膜糖蛋白E可与三种D-甘露糖特异的凝集素(conAPSA及LCA)结合,提示E蛋白的寡糖链为高甘露糖型。D_2V的糖基化非结构蛋白NS_1可与两种D-甘露糖特异的凝集素conA及LCA结合,提示NS_1的寡糖链亦为高甘露糖型。实验结果还显示了一些可能为C6/36细胞感染D_2V后新合成、合成量增加或减少以至完全受抑制的糖蛋白成分,有关这些糖蛋白的性质、功能、意义尚不清楚。在本实验条件下,这种生物素标记凝集素印迹法证明了其敏感性和糖基特异性,可以作为分析各种微量含糖大分子的一种实用方法。 相似文献
779.
Vellareddy Anantharam Sankhavaram R. Patanjali Avadesha Surolia 《Journal of biosciences》1985,8(1-2):403-411
A chitooligosaccharide specific lectin (Luffa acutangula agglutinin) has been purified from the exudate of ridge gourd fruits by affinity chromatography on soybean agglutinin-glycopeptides
coupled to Sepharose-6B. The affinity purified lectin was found homogeneous by polyacrylamide gel electrophoresis, in sodium
dodecyl sulphate-polyacrylamide gels, by gel filtration on Sephadex G-100 and by sedimentation velocity experiments. The relative
molecular weight of this lectin is determined to be 48,000 ±1,000 by gel chromatography and sedimentation equilibrium experiments.
The sedimentation coefficient (S20, w) was obtained to be 4.06 S. The Stokes’ radius of the protein was found to be 2.9 nm by gel filtration. In sodium dodecyl
sulphate-polyacrylamide gel electrophoresis the lectin gave a molecular weight of 24,000 in the presence as well as absence
of 2-mercaptoethanol. The subunits in this dimeric lectin are therefore held by non-covalent interactions alone. The lectin
is not a glycoprotein and circular dichroism spectral studies indicate that this lectin has 31% α-helix and no β-sheet. The
lectin is found to bind specifically to chitooligosaccharides and the affinity of the lectin increases with increasing oligosaccharide
chain length as monitored by near ultra-violet-circular dichroism and intrinsic fluorescence titration. The values of ΔG,
ΔH and ΔS for the binding process showed a pronounced dependence on the size of the oligosaccharide. The values for both ΔH
and ΔS show a significant increase with increase in the oligosaccharide chain length showing that the binding of higher oligomers
is progressively more favoured thermodynamically than chitobiose itself. The thermodynamic data is consistent with an extended
binding site in the lectin which accommodates a tetrasaccharide. Based on the thermodynamic data, blue shifts and fluorescence
enhancement, spatial orientation of chitooligosaccharides in the combining site of the lectin is assigned. 相似文献
780.
固氮相关的两个植物基因转化烟草及其表达 总被引:7,自引:0,他引:7
豆科植物凝集和血红蛋白分别在植物识别其相应的根瘤菌和在根瘤内降低氧分压保护固氮酶的共生固氮作用中起重要作用。将豌豆(Pisum sativa L.)凝集素基因(pl)和Paraqsponia andersonii血红蛋白基因(phb)构建到同一植物表达载体上,通过根癌土壤杆菌(Agrobacterium tumefaciens(Smith et Townsend)Conn)介导法转化烟草(Nics 相似文献