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A Pichia pastoris strain with stereoselective nitrile hydratase activity has been constructed by engineering the co-expression of three genes
derived from Pseudomonas putida. Using a technique that could be widely applicable, the genes encoding nitrile hydratase α and β structural subunits and
P14K accessory protein were first assembled as individual expression cassettes and then incorporated onto one plasmid, which
was integrated into the P. pastoris chromosome. The resulting strain can be used as a catalyst for bioconversions requiring stereospecific nitrile hydrolysis.
Received: 3 November 1998 / Received revision: 25 February1999 / Accepted: 14 March 1999 相似文献
57.
A Gram-negative bacterium producing a heat-stable nitrilase highly active on aliphatic dinitriles 总被引:8,自引:0,他引:8
J. E. Gavagan R. DiCosimo A. Eisenberg S. K. Fager P. W. Folsom E. C. Hann K. J. Schneider R. D. Fallon 《Applied microbiology and biotechnology》1999,52(5):654-659
A Gram-negative bacterial strain, identified as Acidovorax facilis strain 72W, has been isolated from soil by enrichment using 2-ethylsuccinonitrile as the sole nitrogen source. This strain
grows on a variety of aliphatic mono- and dinitriles. Experiments using various heating regimes indicate that nitrile hydratase,
amidase and nitrilase activities are present. The nitrilase is efficient at hydrolyzing aliphatic dinitriles to cyanoacid
intermediates. It has a strong bias for C3–C6 dinitriles over mononitriles of the same chain length. Whole, resting cell hydrolysis of 2-methylglutaronitrile results in
4-cyanopentanoic acid and 2-methylglutaric acid as the major products. Heating, at least 20 min at 50 °C, eliminates nitrile
hydratase and amidase activities, resulting in greater than 97% selectivity to 4-cyanopentanoic acid. The nitrilase activity
has good heat stability, showing a half-life of 22.7 h at 50 °C and a temperature optimum of at least 65 °C for activity.
The strain has been deposited as ATCC 55746.
Received: 26 January 1999 / Received revision: 10 June 1999 / Accepted: 27 June 1999 相似文献
58.
Elite athletes and the gene for angiotensin-converting enzyme. 总被引:7,自引:0,他引:7
R R Taylor C D Mamotte K Fallon F M van Bockxmeer 《Journal of applied physiology》1999,87(3):1035-1037
The deletion (D) allele of the gene for angiotensin-converting enzyme (ACE) is associated with higher plasma and tissue levels of the enzyme and has also been related to a variety of cardiovascular complications, particularly myocardial infarction. On the basis of indirect evidence, we hypothesized that inheritance of the D allele would contribute to elite athletic ability. Over a period of 4 yr, 120 Caucasian athletes who were national (Australian) representatives in sports demanding a high level of aerobic fitness were recruited. Their ACE genotypes were compared with those of a community control group recruited randomly from the electoral roll. There was no difference in ACE genotype frequencies between the two groups. The DD genotype frequency was 30% in athletes and 29% in the control group, and the II genotype frequency was 22.5 and 22%, respectively. The results do not exclude the possibility that ACE genotype could be related to some attribute relating to a specific type of elite athletic ability or that there may be a difference between genders. Larger studies are desirable. 相似文献
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Anna Gerenday Karen M. Shih Carter C. Herman Ann M. Fallon 《Archives of insect biochemistry and physiology》1997,34(1):31-41
Hydroxyurea-resistant Aedes albopictus mosquito cells were selected by incremental exposure of unmutagenized cells to hydroxyurea concentrations ranging from 0.1 to 8 mM. Clonal populations that had become 40-fold more resistant to hydroxyurea than wild-type cells varied in morphology, and their growth rate decreased to a ∼45 h doubling time, relative to an 18 h doubling time in unselected cells. At this level of resistance, the cells remained diploid, with a modal chromosome number of 6. When labelled with 35S[methionine/cysteine], clone HU1062, which grew in the presence of 8 mM hydroxyurea, overproduced a labeled protein with the approximate size of the 45,000 dalton M2 subunit of ribonucleotide reductase. Consistent with this observation, ribonucleotide reductase activity in HU-1062 cells was approximately 10-fold higher than in wild-type control cells. This is the first example of an hydroxyurea-resistant insect cell line. © 1997 Wiley-Liss, Inc. 相似文献
60.
Lara Fallon France Moreau Benjamin G Croft Noura Labib Wen-Jie Gu Edward A Fon 《The Journal of biological chemistry》2002,277(1):486-491
Mutations in the gene encoding parkin cause an autosomal recessive juvenile-onset form of Parkinson's disease. Parkin functions as a RING-type E3 ubiquitin-ligase, coordinating the transfer of ubiquitin to substrate proteins and thereby targeting them for degradation by the proteasome. We now report that the extreme C terminus of parkin, which is selectively truncated by a Parkinson's disease-causing mutation, functions as a class II PDZ-binding motif that binds CASK, the mammalian homolog of Caenorhabditis elegans Lin-2, but not other PDZ proteins in brain extracts. Importantly, parkin co-localizes with CASK at synapses in cultured cortical neurons as well as in postsynaptic densities and lipid rafts in brain. Further, parkin associates not only with CASK but also with other postsynaptic proteins in the N-methyl d-aspartate (NMDA) receptor-signaling complex, in rat brain in vivo. Finally, despite exhibiting E2-dependent ubiquitin ligase activity, rat brain parkin does not ubiquitinate CASK, suggesting that CASK may function in targeting or scaffolding parkin within the postsynaptic complex rather than as a direct substrate for parkin-mediated ubiquitination. These data implicate for the first time a PDZ-mediated interaction between parkin and CASK in neurodegeneration and possibly in ubiquitination of proteins involved in synaptic transmission and plasticity. 相似文献