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341.
342.
Isolation of a multiheme protein with features of a hydrazine-oxidizing enzyme from an anaerobic ammonium-oxidizing enrichment culture 总被引:1,自引:0,他引:1
Shimamura M Nishiyama T Shigetomo H Toyomoto T Kawahara Y Furukawa K Fujii T 《Applied and environmental microbiology》2007,73(4):1065-1072
A multiheme protein having hydrazine-oxidizing activity was purified from enriched culture from a reactor in which an anammox bacterium, strain KSU-1, was dominant. The enzyme has oxidizing activity toward hydrazine but not hydroxylamine and is a 130-kDa homodimer composed of a 62-kDa polypeptide containing eight hemes. It was therefore named hydrazine-oxidizing enzyme (HZO). With cytochrome c as an electron acceptor, the V(max) and K(m) for hydrazine are 6.2 +/- 0.3 micromol/min.mg and 5.5 +/- 0.6 microM, respectively. Hydrazine (25 microM) induced an increase in the proportion of reduced form in the spectrum, whereas hydroxylamine (500 microM) did not. Two genes coding for HZO, hzoA and hzoB, were identified within the metagenomic DNA from the culture. The genes encode the same amino acid sequence except for two residues. The sequences deduced from these genes showed low-level identities (<30%) to those of all of the hydroxylamine oxidoreductases reported but are highly homologous to two hao genes found by sequencing the genome of "Candidatus Kuenenia stuttgartiensis" (88% and 89% identities). The purified enzyme might therefore be a novel hydrazine-oxidizing enzyme having a critical role in anaerobic ammonium oxidation. 相似文献
343.
Watsuji TO Yamada S Yamabe T Watanabe Y Kato T Saito T Ueda K Beppu T 《Applied and environmental microbiology》2007,73(19):6159-6165
Symbiobacterium thermophilum is a syntrophic bacterium whose growth depends on coculture with a Bacillus sp. Recently, we discovered that CO(2) generated by Bacillus is the major inducer for the growth of S. thermophilum; however, the evidence suggested that an additional element is required for its full growth. Here, we studied the self-growth-inhibitory substances produced by S. thermophilum. We succeeded in purifying two substances from an ether extract of the culture supernatant of S. thermophilum by multiple steps of reverse-phase chromatography. Electron ionization mass spectrometry and nuclear magnetic resonance analyses of the purified preparation identified the substances as 2,2-bis(3'-indolyl)indoxyl (BII) and 1,1-bis(3'-indolyl)ethane (BIE). The pure growth of S. thermophilum was inhibited by authentic BII and BIE with MICs of 12 and 7 microg/ml, respectively; however, its growth in coculture with Bacillus was not inhibited by BII at the saturation concentration and was inhibited by BIE with an MIC of 14 microg/ml. Both BII and BIE inhibited the growth of other microorganisms. Unexpectedly, the accumulation levels of both BII and BIE in the pure culture of S. thermophilum were far lower than the MICs (<0.1 microg/ml) while a marked amount of BIE (6 to 7 microg/ml) equivalent to the MIC had accumulated in the coculture. An exogenous supply of surfactin alleviated the sensitivities of several BIE-sensitive bacteria against BIE. The results suggest that Bacillus benefits S. thermophilum by detoxifying BII and BIE in the coculture. A similar mechanism may underlie mutualistic relationships between different microorganisms. 相似文献
344.
345.
Yamashita S Satoi M Iwasa Y Honda K Sameshima Y Omasa T Kato J Ohtake H 《Applied microbiology and biotechnology》2007,74(4):761-767
Rhodococcus opacus strain B-4, which has recently been isolated as an organic solvent-tolerant bacterium, has a high hydrophobicity and exhibits
a high affinity for hydrocarbons. This bacterium was able to survive for at least 5 days in organic solvents, including n-tetradecane, oleyl alcohol, and bis(2-ethylhexyl) phthalate (BEHP), which contained water less than 1% (w/v). The biocatalytic ability of R. opacus B-4 was demonstrated in the essentially nonaqueous BEHP using indigo production from indole as a model conversion. By the
catabolism of oleic acid for NADH regeneration, indigo production increased up to 71.6 μg ml−1 by 24 h. 相似文献
346.
BACKGROUND/AIMS: Although insulin-like factor 3 (INSL3) and its receptor leucine-rich repeat-containing G protein-coupled receptor 8/G protein-coupled receptor affecting testis descent (LGR8/GREAT) are essential for the gubernacular development, mutations of INSL3 and LGR8/GREAT are infrequent in patients with cryptorchidism (CO), and there is no report documenting a positive association of CO with a polymorphism in INSL3 or LGR8/GREAT. Here, we further examined the relevance of INSL3 and LGR8/GREAT mutations and polymorphisms to the development of CO. METHODS: Sixty-two Japanese CO patients and 60 fertile males were studied. INSL3 was analyzed by direct sequencing and restriction enzyme digestion, and LGR8/GREAT was examined by denaturing high-performance liquid chromatography followed by direct sequencing for exons with abnormal chromatogram patterns. RESULTS: No definitive mutation was identified in both genes. Six polymorphisms were detected in INSL3 or LGR8/GREAT and Thr/Thr genotype of Ala60Thr polymorphism in INSL3 was strongly associated with CO (p=0.0024, odds ratio=5.3, 95% confidence interval=1.7-17). CONCLUSION: The results, in conjunction with the previous data, suggest that mutations of INSL3 and LGR8/GREAT remain rare, and that the Thr/Thr genotype of Ala60Thr polymorphism in INSL3 may constitute a susceptibility factor for the development of CO. 相似文献
347.
Kai H Morioka Y Tomida M Takahashi T Hattori M Hanasaki K Koike K Chiba H Shinohara S Kanemasa T Iwamoto Y Takahashi K Yamaguchi Y Baba T Yoshikawa T Takenaka H 《Bioorganic & medicinal chemistry letters》2007,17(14):3925-3929
Structure-activity relationships and efforts to optimize the pharmacokinetic profile of a class of 2-arylimino-5,6-dihydro-4H-1,3-thiazines as cannabinoid receptor agonists are described. Among the compounds examined, compound 14 showed potent affinity and high selectivity for CB2, and compound 23 showed potent affinities against CB1 and CB2. These compounds displayed oral bioavailability. 相似文献
348.
Yamamoto T Fujita K Asari S Chiba A Kataba Y Ohsumi K Ohmuta N Iida Y Ijichi C Iwayama S Fukuchi N Shoji M 《Bioorganic & medicinal chemistry letters》2007,17(13):3736-3740
A series of isoxazole derivatives were synthesized and their antagonistic activities against LPA stimulation on both LPA(1)/CHO cells and rHSC cells were evaluated. Among them, 3-(4-[4-[1-(2-chloro-cyclopent-1-enyl)-ethoxycarbonylamino]-isoxazol-3- y]]-benzylsulfanyl)-propionic acid (34) showed the most potent activities. 相似文献
349.
Oleg Shchepin Yuri Novozhilov Jan Woyzichovski Manuela Bog Ilya Prikhodko Nadezhda Fedorova Vladimir Gmoshinskiy Mathilde Borg Dahl Nikki H. A. Dagamac Yuka Yajima Martin Schnittler 《Molecular ecology》2022,31(1):372-390
Myxomycetes are terrestrial protists with many presumably cosmopolitan species dispersing via airborne spores. A truly cosmopolitan species would suffer from outbreeding depression hampering local adaptation, while locally adapted species with limited distribution would be at a higher risk of extinction in changing environments. Here, we investigate intraspecific genetic diversity and phylogeography of Physarum albescens over the entire Northern Hemisphere. We sequenced 324 field collections of fruit bodies for 1–3 genetic markers (SSU, EF1A, COI) and analysed 98 specimens with genotyping by sequencing. The structure of the three-gene phylogeny, SNP-based phylogeny, phylogenetic networks, and the observed recombination pattern of three independently inherited gene markers can be best explained by the presence of at least 18 reproductively isolated groups, which can be seen as cryptic species. In all intensively sampled regions and in many localities, members of several phylogroups coexisted. Some phylogroups were found to be abundant in only one region and completely absent in other well-studied regions, and thus may represent regional endemics. Our results demonstrate that the widely distributed myxomycete species Ph. albescens represents a complex of at least 18 cryptic species, and some of these seem to have a limited geographical distribution. In addition, the presence of groups of presumably clonal specimens suggests that sexual and asexual reproduction coexist in natural populations of myxomycetes. 相似文献
350.
Akiyoshi Yamada Norio Hayakawa Chika Saito Yuka Horimai Hiroki Misawa Takashi Yamanaka Masaki Fukuda 《Mycoscience》2019,60(2):102-109
Matsutake (Tricholoma matsutake) is a commercially valuable edible ectomycorrhizal mushroom. The physiological traits of T. matsutake have been previously assessed using mycelial isolates isolated from basidiomata; however, few studies have focused on basidiospores. Here, we report that sibling T. matsutake isolates generated from basidiospores on a single basidioma show distinct physiological variation. We first established 145 isolates of T. matsutake on modified Norkrans' C (MNC) agar medium and found that their radial growth varied significantly. The mycelial biomasses of nine isolates with different growth rates were reduced on low-carbon and low-nitrogen MNC media. However, the colony diam of one isolate was significantly elevated on low-carbon medium, and the colony diam of two isolates were significantly elevated on low-nitrogen medium. In co-cultures of two or three isolates, commensal and amensal interactions were observed. The physiological variation induced by low carbon and nitrogen levels and the mycelial interactions between sibling isolates imply mechanisms for the genetic and functional characteristics of mycelia of T. matsutake. 相似文献