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121.
Mihara H Muramatsu H Kakutani R Yasuda M Ueda M Kurihara T Esaki N 《The FEBS journal》2005,272(5):1117-1123
We found N-methyl-L-amino acid dehydrogenase activity in various bacterial strains, such as Pseudomonas putida and Bacillus alvei, and cloned the gene from P. putida ATCC12633 into Escherichia coli. The enzyme purified to homogeneity from recombinant E. coli catalyzed the NADPH-dependent formation of N-alkyl-L-amino acids from the corresponding alpha-oxo acids (e.g. pyruvate, phenylpyruvate, and hydroxypyruvate) and alkylamines (e.g. methylamine, ethylamine, and propylamine). Ammonia was inert as a substrate, and the enzyme was clearly distinct from conventional NAD(P)-dependent amino acid dehydrogenases, such as alanine dehydrogenase (EC 1.4.1.1). NADPH was more than 300 times more efficient than NADH as a hydrogen donor in the enzymatic reductive amination. Primary structure analysis revealed that the enzyme belongs to a new NAD(P)-dependent oxidoreductase superfamily, the members of which show no sequence homology to conventional NAD(P)-dependent amino acid dehydrogenases and opine dehydrogenases. 相似文献
122.
Salicylic acid accumulation under O3 exposure is regulated by ethylene in tobacco plants 总被引:2,自引:0,他引:2
123.
Takakura T Ito T Yagi S Notsu Y Itakura T Nakamura T Inagaki K Esaki N Hoffman RM Takimoto A 《Applied microbiology and biotechnology》2006,70(2):183-192
l-Methionine γ-lyase is a pyridoxal 5′-phosphate-dependent enzyme which has tumor selective anticancer activity. An efficient
production process for the recombinant enzyme was constructed by using the overexpression plasmid in Escherichia coli, large-scale cultivation, and practical crystallization on an industrial scale. The plasmid was optimized with a promoter
and the region of the ribosome-binding site. Plasmid pMGLTrc03, which has a trc promoter and a spacing of 12 nucleotides between the Shine-Dalgarno sequence and the ATG translation initiation codon, was
selected as the most suitable plasmid. The transformants produced the enzyme, which intracellularly accumulated at 2.1 mg/ml
as an active form and accounted for 43% of the total proteins in the soluble fraction by simple batch fermentation using a
500-l fermentor. The crystals were directly obtained from crude enzyme with 87% yield by a crystallization in the presence
of 9.0% polyethylene glycol 6000, 3.6% ammonium sulfate, and 0.18 M sodium chloride using a 100-l crystallizer. After recrystallization,
the enzyme was purified by anion-exchange column chromatography to remove endotoxins and by gel filtration for polishing.
We prepared 600 g of purified enzyme with a low endotoxin content of sufficient quality for therapeutical use, with a 41%
overall yield in the purification process. 相似文献
124.
Phytochelatins (PCs) are heavy metal binding peptides that play an important role in sequestration and detoxification of heavy
metals in plants. In this study, our goal was to develop transgenic plants with increased tolerance for and accumulation of
heavy metals from soil by expressing an Arabidopsis
thaliana
AtPCS1 gene, encoding phytochelatin synthase (PCS), in Indian mustard (Brassica juncea L.). A 35S promoter fused to a FLAG–tagged AtPCS1 cDNA was expressed in Indian mustard, and transgenic lines, designated pc lines, were evaluated for tolerance to and accumulation
of Cd and Zn. Transgenic plants with moderate AtPCS1 expression levels showed significantly higher tolerance to Cd and Zn
stress, but accumulated significantly less Cd and Zn than wild type plants in both shoot and root tissues. However, transgenic
plants with highest expression of the transgene did not exhibit enhanced Cd and Zn tolerance. Shoots of Cd-treated pc plants
had significantly higher levels of phytochelatins and thiols than wild-type plants. Significantly lower concentrations of
gluthatione in Cd-treated shoot and root tissues of transgenic plants were observed. Moderate expression levels of phytochelatin
synthase improved the ability of Indian mustard to tolerate certain levels of heavy metals, but at the same time did not increase
the accumulation potential for Cd and Zn. 相似文献
125.
Role of phosphoenolpyruvate in the NADP-isocitrate dehydrogenase and isocitrate lyase reaction in Escherichia coli 下载免费PDF全文
Phosphoenolpyruvate inhibited Escherichia coli NADP-isocitrate dehydrogenase allosterically (Ki of 0.31 mM) and isocitrate lyase uncompetitively (Ki' of 0.893 mM). Phosphoenolpyruvate enhances the uncompetitive inhibition of isocitrate lyase by increasing isocitrate, which protects isocitrate dehydrogenase from the inhibition, and contributes to the control through the tricarboxylic acid cycle and glyoxylate shunt. 相似文献
126.
Nobue Kitanaka Junichi Kitanaka Tomohiro Tatsuta Koh-ichi Tanaka Kaname Watabe Nobuyoshi Nishiyama Yoshio Morita Motohiko Takemura 《Neurochemical research》2010,35(5):749-760
A variety of drug treatment regimens have been proposed to model the dysphoric state observed during methamphetamine (METH)
withdrawal in rats, but little has been established in experiments using mice. In male ICR mice, a fixed-dose injection regimen
of METH (1.0 or 2.5 mg/kg, i.p., twice daily for 10 consecutive days) induced a significant decrease in the time spent in
open arms in an elevated plus maze after 5 days of drug abstinence. Under an escalating-dose injection regimen (0.2–2.0 mg/kg,
i.p., 3 times daily for 4 days, total: 15 mg/kg/animal) or continuous subcutaneous administration with osmotic mini-pumps
(15 or 76 mg/kg of METH for 2 weeks), no significant behavioral change was observed after 5 days of drug abstinence, compared
with control animals. Reduced gains in body weight were observed during repeated treatment with METH in the fixed-dose injection
and mini-pump treatment regimens, but not the escalating-dose injection regimen. HPLC analysis revealed significant decreases
in the level of cerebral 3-methoxy-4-hydroxyphenylglycol, a norepinephrine metabolite, and norepinephrine turnover, which
may be attributed to the expression of anxiety-related behavior in the elevated plus maze. These observations suggest that
the mice treated with a fixed-dose of METH may model the anxiety-related behavior observed in the dysphoric state induced
by METH withdrawal in humans. 相似文献
127.
Kosaka N Iguchi H Yoshioka Y Hagiwara K Takeshita F Ochiya T 《The Journal of biological chemistry》2012,287(2):1397-1405
Normal epithelial cells regulate the secretion of autocrine and paracrine factors that prevent aberrant growth of neighboring cells, leading to healthy development and normal metabolism. One reason for tumor initiation is considered to be a failure of this homeostatic cell competitive system. Here we identify tumor-suppressive microRNAs (miRNAs) secreted by normal cells as anti-proliferative signal entities. Culture supernatant of normal epithelial prostate PNT-2 cells attenuated proliferation of PC-3M-luc cells, prostate cancer cells. Global analysis of miRNA expression signature revealed that a variety of tumor-suppressive miRNAs are released from PNT-2 cells. Of these miRNAs, secretory miR-143 could induce growth inhibition exclusively in cancer cells in vitro and in vivo. These results suggest that secretory tumor-suppressive miRNAs can act as a death signal in a cell competitive process. This study provides a novel insight into a tumor initiation mechanism. 相似文献
128.
129.
Kawashima Ichiro; Inokuchi Yoshio; Chino Mitsuo; Kimura Masami; Shimizu Nobuyoshi 《Plant & cell physiology》1991,32(6):913-916
Using a synthetic oligonucleotide that corresponded to the consensusnucleotide sequence of the N-terminal region of mammalian metallothioneinas probe, we isolated a cDNA clone from a soybean library. Theclone had an ORF that encode a protein of 79 amino acids whichshowed significant homology to both N- and C-terminal regionsof mammalian and Neurospora crassa metallothioneins
4Present address: Department of Biosciences, Teikyo University,Toyosatodai, Utsunomiya, Tochigi, 320 Japan (Received March 13, 1991; Accepted June 17, 1991) 相似文献
130.
Nobuyoshi Niwa Yusuke Yamagishi Hiroshi Murakami Hiroaki Suga 《Bioorganic & medicinal chemistry letters》2009,19(14):3892-3894
We have developed a new flexizyme (a flexible de novo tRNA acylation ribozyme) system, a pair of amino-derivatized benzyl thioester (ABT) and amino flexizyme (aFx). ABT bearing the ammonium ion was designed to render the acyl-donor substrates better water solubility. Although the previously reported flexizymes (eFx and dFx) did not show acylation activity for the ABT derivatives, a new flexizyme variant aFx, generated by in vitro selection against an amino acid activated ABT, exhibits high selectivity toward those activated ABT. The flexizymes system including aFx, eFx, and dFx enables us to prepare a wide variety of acyl-tRNAs charged with non-proteinogenic amino acids. 相似文献