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351.
A novel dark-inducible protein, LeDI-2, and its involvement in root-specific secondary metabolism in Lithospermum erythrorhizon
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Lithospermum erythrorhizon produces red naphthoquinone pigments that are shikonin derivatives. They are accumulated exclusively in the roots of this plant. The biosynthesis of shikonin is strongly inhibited by light, even though other environmental conditions are optimized. Thus, L. erythrorhizon dark-inducible genes (LeDIs) were isolated to investigate the regulatory mechanism of shikonin biosynthesis. LeDI-2, showing the strict dark-specific expression, was further characterized by use of cell suspension cultures and hairy root cultures as model systems. Its mRNA accumulation showed a similar pattern with that of shikonin. In the intact plants LeDI-2 expression was observed solely in the root, and the longitudinal distribution of its mRNA was also in accordance to that of shikonin. LeDI-2 encoded a very hydrophobic polypeptide of 114 amino acids that shared significant similarities with some root-specific polypeptides such as ZRP3 (maize) and RcC3 (rice). Reduction of LeDI-2 expression by its antisense DNA in hairy roots of L. erythrorhizon decreased the shikonin accumulation, whereas other biosynthetic enzymes, e.g. p-hydroxybenzoic acid:geranyltransferase, which catalyzed a critical biosynthetic step, showed similar activity as the wild-type clone. This is the first report of the gene that is involved in production of secondary metabolites without affecting biosynthetic enzyme activities. 相似文献
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353.
Taniguchi S Yazaki K Yabuuchi R Kawakami K Ito H Hatano T Yoshida T 《Phytochemistry》2000,53(3):357-363
Adventitious root cultures of Rhus javanica L. produced large amounts of galloylglucoses (gallotannins) and an anthocyanidin, riccionidin A, formerly found only in liverworts. Production of both galloylglucoses and riccionidin A in the adventitious root culture system was suppressed by light. The Rhus root culture showed the highest productivity for those secondary metabolites in a modified Linsmaier-Skoog (LS) liquid medium containing 30 mM NH4+ and 30 mM NO3- as nitrogen sources in the presence of 10(-6) M 3-indoleacetic acid (IAA). 相似文献
354.
Cytochrome d was spectroscopically detected in membrane fractions of the amino-acid-fermenting, high-G+C gram-positive bacterium Corynebacterium glutamicum. Inhibition of NADH oxidase activity in the membranes by cyanide suggested that the main terminal respiratory oxidase during the stationary phase was a type of cytochrome bd. Cytochrome bd-type quinol oxidase, purified from the membranes, was composed of two subunits. Its reduced form showed absorption peaks at 627, 595, and 560 nm, which were due to haem d, high-spin protohaem, and low-spin protohaem, respectively. The air-oxidised form showed a peak at 645 nm, which might be due to oxygenated ferrous haem d. The spectral features and the size of subunit I are more similar to the properties of cytochromes bd from Proteobacteria, such as Escherichia coli, than to those of cytochrome bd from low-G+C gram-positive bacteria, such as Bacillus stearothermophilus. The menaquinol oxidase activity of the purified cytochrome bd was low, but was enhanced about fivefold by pre-incubating the enzyme with menaquinones. The order of effectiveness of quinols as oxidase substrates was clearly different from that of quinones as the activators of enzyme activity. Furthermore, activation was destroyed by ultraviolet irradiation of the pre-incubated enzyme and then restored by a second incubation with menaquinone. These results indicate that the enzymatic properties of this new oxidase are more similar to the properties of cytochromes bd from low-G+C gram-positive bacterial than to those of proteobacterial counterparts. They also suggest that the enzyme has a second quinone-binding site essential for full activity, in addition to the active centre for substrate oxidation. By using probes based on partial peptide sequences of the subunits, the genes for the two subunits of C. glutamicum cytochrome bd were cloned. The deduced amino acid sequence demonstrated that subunit I lacks the C-terminal half of the Q loop and that the primary structure of C. glutamicum cytochrome bd is more similar to that of other gram-positive bacteria than to proteobacterial cytochromes bd. 相似文献
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356.
Masabumi Komatsu Hiroyuki Tobita Makoto Watanabe Kenichi Yazaki Takayoshi Koike Mitsutoshi Kitao 《Physiologia plantarum》2013,147(2):159-168
To determine the effects of elevated CO2 concentration ([CO2]) on the temperature‐dependent photosynthetic properties, we measured gas exchange and chlorophyll fluorescence at various leaf temperatures (15, 20, 25, 30, 35 and 40°C) in 1‐year‐old seedlings of the Japanese white birch (Betula platyphylla var. japonica), grown in a phytotron under natural daylight at two [CO2] levels (ambient: 400 µmol mol?1 and elevated: 800 µmol mol?1) and limited N availability (90 mg N plant?1). Plants grown under elevated [CO2] exhibited photosynthetic downregulation, indicated by a decrease in the carboxylation capacity of Rubisco. At temperatures above 30°C, the net photosynthetic rates of elevated‐CO2‐grown plants exceeded those grown under ambient [CO2] when compared at their growth [CO2]. Electron transport rates were significantly lower in elevated‐CO2‐grown plants than ambient‐CO2‐grown ones at temperatures below 25°C. However, no significant difference was observed in the fraction of excess light energy [(1 ? qP)× Fv′/Fm′] between CO2 treatments across the temperature range. The quantum yield of regulated non‐photochemical energy loss was significantly higher in elevated‐CO2‐grown plants than ambient, when compared at their respective growth [CO2] below 25°C. These results suggest that elevated‐CO2‐induced downregulation might not exacerbate the temperature‐dependent susceptibility to photoinhibition, because reduced energy consumption by electron transport was compensated for by increased thermal energy dissipation at low temperatures. 相似文献
357.
Atsushi Murano Sei Fujiwara Masao Horiba Junshi Miyamoto 《Bioscience, biotechnology, and biochemistry》2013,77(8):1200-1207
Determination of 5-benzyl-3-furylmethyl-dl-cis, trans-chrysanthemate (resmethrin) has been carried out by colorimetry and ultraviolet spectrophotometry after thin-layer chromatographic separation and also by gas-liquid chromatography (GLC). The analytical results were lower than the actual contents by the former two methods, because the sensitivity of cis-resmethrin was lower than that of trans-resmethrin. On the other hand, the sensitivity of both cis- and trans-resmethrins to a hydrogen flame ionization detector of GLC was substantially identical and resmethrin (trans plus cis) was accurately determined by using dicyclohexylphthalate as an internal standard. The retention times of cis- and trans-isomers were 4.6 and 5.1 minutes, respectively, and therefore a DISC type integrator was used for the exact and precise calculation of peak area. Furthermore, these two geometrical isomers were separated by GLC and the results obtained by analyzing the mixtures indicates that the ratio can be accurately determined by their peak area ratio. 相似文献
358.
Dai Kishida Akinori Nakamura Masahide Yazaki Ayako Tsuchiya-Suzuki Masayuki Matsuda Shu-ichi Ikeda 《Arthritis research & therapy》2014,16(5)
Introduction
Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disease characterized by recurrent self-limiting fever and serositis that mainly affects Mediterranean populations. Many patients with FMF have been reported in Japan due to increasing recognition of this condition and the availability of genetic analysis for the gene responsible, MEFV. The present study was performed to elucidate the clinical characteristics of Japanese FMF patients and to examine the precise genotype-phenotype correlation in a large cohort of Japanese FMF patients.Methods
We analyzed the MEFV genotypes and clinical manifestations in 116 patients clinically diagnosed as having FMF and with at least one mutation.Results
The most frequent mutation in Japanese patients was E148Q (40.2%), followed by M694I (21.0%), L110P (18.8%), P369S (5.4%), and R408Q (5.4%). In contrast, common mutations seen in Mediterranean patients, such as M694V, V726A, and M680I, were not detected in this population. The clinical features with M694I were associated with more severe clinical course compared to those seen with E148Q. P369S/R408Q showed variable phenotypes with regard to both clinical manifestations and severity. Patients with M694I showed a very favorable response to colchicine therapy, while those with P369S and R408Q did not.Conclusions
Clinical features and efficacy of treatment in Japanese FMF patients vary widely according to the specific MEFV gene mutation, and therefore genetic analysis should be performed for diagnosis in cases of Japanese FMF.Electronic supplementary material
The online version of this article (doi:10.1186/s13075-014-0439-7) contains supplementary material, which is available to authorized users. 相似文献359.
360.
Sorgente A Chierchia GB Capulzini L Yazaki Y Muller-Burri A Bayrak F Sarkozy A de Asmundis C Paparella G Brugada B 《Indian pacing and electrophysiology journal》2010,10(11):486-495