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排序方式: 共有377条查询结果,搜索用时 453 毫秒
311.
Marie Zarevúcka Martin Rejzek Michal Hoskovec Ales Svatos Zdenek Wimmer Bohumír Koutek Marie-Dominique Legoy 《Biotechnology letters》1997,19(8):745-750
Lipase biocatalysis was investigated as a tool for the production of esters by two model reactions, esterification of 1-butanol with 2-methyl-1-pentanoic acid and irreversible transesterification between 2-methyl-1-pentanol and vinyl acetate. The reactions were carried out in hexane using lipases from Candida cylindracea and porcine pancreas. The initial water content influenced both the yield of the ester and the enantioselectivity of the reaction (esterifica-tions) or the ester formation only (transesterifications). 相似文献
312.
Vanco J Marek J Trávnícek Z Racanská E Muselík J Svajlenová O 《Journal of inorganic biochemistry》2008,102(4):595-605
A series of copper(II) and zinc(II) complexes involving a tridentate O,N,O'-donor Schiff base derived from salicylaldehyde and beta-alanine {i.e. N-salicylidene-beta-alanine(2-), (L)}, having the composition [Cu(2)(L)(2)(H(2)O)].H(2)O (1), [Cu(L)(H(2)O)](n) (2), and [Zn(L)(H(2)O)](n) (3), have been prepared and characterized by elemental analyses, UV-visible (UV-VIS), FT-IR and ESI-MS spectra, and thermal analyses. Complexes 1 and 2 have been investigated by single crystal X-ray analysis and also by temperature dependent magnetic susceptibility measurements (294-80K). All prepared complexes have been evaluated by the antiperoxynitrite activity assay and alloxan-induced diabetes model. The significant antioxidant and antidiabetic activities have been found in the case of both copper(II) complexes 1 and 2. In spite of first two complexes, the zinc(II) complex 3, as well as the potassium salt of the ligand (KHL) showed only insignificant protective effect against the tyrosine nitration in vitro. 相似文献
313.
The character of programmed cell death (PCD) in plants differs in connection with the context, triggering factors and differentiation state of the target cells. To study the interconnections between cell cycle progression and cell death induction, we treated synchronized tobacco BY-2 cells with cadmium ions that represent a general abiotic stressor influencing both dividing and differentiated cells in planta. Cadmium induced massive cell death after application in all stages of the cell cycle; however, both the progression and the forms of the cell death differed pronouncedly. Apoptosis-like PCD induced by cadmium application in the S and G2 was characterized by pronounced internucleosomal DNA fragmentation. In contrast, application of cadmium in M and G1 phases was not accompanied by DNA cleavage, indicating suppression of autolysis and non-programmed character of the death. We interpret these results in the context of the situation in planta, where the induction of apoptosis-like PCD in the S and G2 phase might be connected with a need to preserve genetic integrity of dividing meristematic cells, whereas suppression of PCD response in differentiated cells (situated in G1/G0 phase) might help to avoid death of the whole plant, and thus enable initiation of the recovery and adaptation processes. 相似文献
314.
Comprehensive resequence analysis of a 136 kb region of human chromosome 8q24 associated with prostate and colon cancers 总被引:1,自引:0,他引:1
Yeager M Xiao N Hayes RB Bouffard P Desany B Burdett L Orr N Matthews C Qi L Crenshaw A Markovic Z Fredrikson KM Jacobs KB Amundadottir L Jarvie TP Hunter DJ Hoover R Thomas G Harkins TT Chanock SJ 《Human genetics》2008,124(2):161-170
Recently, genome-wide association studies have identified loci across a segment of chromosome 8q24 (128,100,000–128,700,000)
associated with the risk of breast, colon and prostate cancers. At least three regions of 8q24 have been independently associated
with prostate cancer risk; the most centromeric of which appears to be population specific. Haplotypes in two contiguous but
independent loci, marked by rs6983267 and rs1447295, have been identified in the Cancer Genetic Markers of Susceptibility
project (), which genotyped more than 5,000 prostate cancer cases and 5,000 controls of European origin. The rs6983267 locus is also
strongly associated with colorectal cancer. To ascertain a comprehensive catalog of common single-nucleotide polymorphisms
(SNPs) across the two regions, we conducted a resequence analysis of 136 kb (chr8: 128,473,000–128,609,802) using the Roche/454
next-generation sequencing technology in 39 prostate cancer cases and 40 controls of European origin. We have characterized
a comprehensive catalog of common (MAF > 1%) SNPs within this region, including 442 novel SNPs and have determined the pattern
of linkage disequilibrium across the region. Our study has generated a detailed map of genetic variation across the region,
which should be useful for choosing SNPs for fine mapping of association signals in 8q24 and investigations of the functional
consequences of select common variants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
315.
The breakpoint junction on a ring chromosome 17 in a girl with autism, mental retardation, mild dysmorphism and neurofibromatosis was identified and analysed at the nucleotide level. The extent of the deleted segments was about 1.9 Mb on 17p and about 1.0 Mb on 17q. The structure of the junction between the 17p and 17q arms, especially the lack of significant homology between the juxtaposed genomic regions and the presence of short microhomology at the junction site, indicated non-homologous end joining as the most likely mechanism leading to the rearrangement. In addition to the 17p-17q junction itself, a de novo 1 kb deletion in a distance of 400 bp from the junction was identified, which arose most likely as a part of the rearrangement. The defect directly inactivated 3 genes, and the deleted terminal chromosome segments harboured 27 and 14 protein-coding genes from 17p and 17q, respectively. Several of the genes affected by the rearrangement are candidates for the symptoms observed in the patient. Additional rearrangements similar to the 1 kb deletion observed in our patient may remain undetected but can participate in the phenotype of patients with chromosomal aberrations. They can also be the reason for repeated failures to clone breakpoint junctions in other patients described in the literature. 相似文献
316.
317.
318.
Andrei P. Smertenko Despina Kaloriti Hsin-Yu Chang Jindriska Fiserova Zdenek Opatrny Patrick J. Hussey 《The Plant cell》2008,20(12):3346-3358
The microtubule-associated protein, MAP65, is a member of a family of divergent microtubule-associated proteins from different organisms generally involved in maintaining the integrity of the central spindle in mitosis. The dicotyledon Arabidopsis thaliana and the monocotyledon rice (Oryza sativa) genomes contain 9 and 11 MAP65 genes, respectively. In this work, we show that the majority of these proteins fall into five phylogenetic clades, with the greatest variation between clades being in the C-terminal random coil domain. At least one Arabidopsis and one rice isotype is within each clade, indicating a functional specification for the C terminus. In At MAP65-1, the C-terminal domain is a microtubule binding region (MTB2) harboring the phosphorylation sites that control its activity. The At MAP65 isotypes show differential localization to microtubule arrays and promote microtubule polymerization with variable efficiency in a MTB2-dependent manner. In vivo studies demonstrate that the dynamics of the association and dissociation of different MAP65 isotypes with microtubules can vary up to 10-fold and that this correlates with their ability to promote microtubule polymerization. Our data demonstrate that the C-terminal variable region, MTB2, determines the dynamic properties of individual isotypes and suggest that slower turnover is conditional for more efficient microtubule polymerization. 相似文献
319.
The new version of the TRITON program provides user-friendly graphical tools for modeling protein mutants using the external program MODELLER and for docking ligands into the mutants using the external program AutoDock. TRITON can now be used to design ligand-binding proteins, to study protein-ligand binding mechanisms or simply to dock any ligand to a protein. Availability: Executable files of TRITON are available free of charge for academic users at http://ncbr.chemi.muni.cz/triton/ 相似文献
320.
Cesnek M Holý A Masojídková M Kmonícková E Zídek Z 《Bioorganic & medicinal chemistry》2008,16(2):965-980
A series of novel 9-, 7- and 3-substituted 2- or 6-guanidinopurines as analogues of potent antiviral and immunobiologically active compound enantiomers of PMPDAP was synthesized and evaluated for their biological activity. Compounds containing the combination of guanidino and amino group at the purine moiety enhanced the interferon-gamma-triggered NO production in murine macrophages and stimulated the secretion of cytokines and chemokines in both murine macrophages and human peripheral blood mononuclear cells. The most active compounds are 27 and 54. None of the compounds tested exhibited any significant cytostatic effect or antiviral effect. 相似文献