全文获取类型
收费全文 | 525篇 |
免费 | 28篇 |
出版年
2021年 | 5篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 57篇 |
2012年 | 19篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2009年 | 7篇 |
2008年 | 32篇 |
2007年 | 19篇 |
2006年 | 28篇 |
2005年 | 23篇 |
2004年 | 27篇 |
2003年 | 14篇 |
2002年 | 26篇 |
2001年 | 21篇 |
2000年 | 21篇 |
1999年 | 16篇 |
1998年 | 8篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1986年 | 9篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 6篇 |
1975年 | 2篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1968年 | 5篇 |
1967年 | 2篇 |
1966年 | 3篇 |
1965年 | 2篇 |
1915年 | 2篇 |
排序方式: 共有553条查询结果,搜索用时 15 毫秒
61.
Plastocyanin was purified from the gymnosperm Ginkgo biloba L., and its complete amino acid sequence was determined. The protein was shown to contain Phe-83 instead of Tyr-83 conserved in other land plant plastocyanins. This is the first report of the characterization and complete amino acid sequence of a gymnosperm plastocyanin. 相似文献
62.
Maeda I Yamashiro H Yoshioka D Onodera M Ueda S Kawase M Miyasaka H Yagi K 《Applied microbiology and biotechnology》2006,70(4):397-402
A colorimetric whole-cell sensor for dimethyl sulfide (DMS) was constructed based on the in vivo conversion of intrinsic pigments
in response to the analyte. In a marine bacterium, Rhodovulum sulfidophilum, carotenoids are synthesized via the spheroidene pathway. In this pathway, demethylspheroidene, a yellow carotenoid, is converted
to spheroidene under catalysis of O-methyltransferase. Spheroidene monooxygenase (CrtA) catalyzes the terminal step of the pathway and converts spheroidene to
spheroidenone, a red carotenoid. Here, the CrtA gene in R. sulfidophilum was removed and then reintroduced downstream of the DMS dehydrogenase gene promoter. Using this whole-cell sensor, 3 μM DMS
or dimethyl sulfoxide can be detected without adding any color-forming reagent. The ratio of the red spheroidenone to total
carotenoids increased, as the DMS concentration was raised to 0.3 mM. Comparison of the signal to the background color indicated
a shift in the color coordinate from a yellow to a red hue. An intense signal was obtained with 1-day incubation at a high
cell density when sensor cells at the exponential growth phase were used. These results show that the genetically engineered
R. sulfidophilum cells can be used to monitor the quality of marine aquacultural environments by the naked eye. 相似文献
63.
64.
Curious low-temperature solubility of cellulose triacetates (CTA; here we use nominally "CTA," but the sample still contains 7% of C-6 position hydroxyls) in an organic solvent, methyl acetate (MA), was studied by a newly designed low-temperature type of DLS apparatus, which enabled for the first time to investigate the structural change of CTA in solution from 45 degrees C down to -100 degrees C. A molecularly dissolved CTA was found to coexist with three types of self-assemblies over all the temperature ranges except for the three specific temperatures T* of 30, -10, and -75 degrees C. However, these multiple self-assemblies are not in real thermodynamic equilibrium but in a metastable state, which could be stabilized effectively by the intermolecular hydrogen bonding (HB) with the help of the dipole interaction at low temperatures. In more detail, with decreasing temperature, these assemblies performed the structural reorganization drastically at three T*'s and would finally be frozen in a physical gel structure at -99 degrees C; around the freezing temperature of MA, CTA molecules could be trapped homogeneously in the frozen MA. The crucial role in such structural reorganizations is played by the balance between the intermolecular HB and the dipole interaction worked in the highly electronegative solvent. Because these interactions, which are mediated by the solvent electronegativity, change drastically with temperature, they result in the control of not only the single CTA chain conformation (= the intramolecular HB) but also the binding ways of the intermolecular HBs between CTA molecules and they induce multitudinous metastable structures in solution. Here it is noted that HB could work mainly between the C-6 position hydroxyls in the anhydroglucose units of CTA and are essentially effective at low temperatures. 相似文献
65.
Genistein and orobol 8-C-beta-D-glucopyranosides (1 and 3) were firstly synthesized in overall yields of 39% and 41% from 2,4-di-O-benzylphloroacetophenone (4), as follows: (1) the formation of the chalcone (6, 7) by aldol condensation of the benzyl-protected C-glycosylphloroacetophenone (5), a key intermediate of the total synthesis of 1 and 3 and synthesized by a C-glycosylation method involving the O-->C glycoside rearrangement of 4 in 96% yield; (2) the formation of isoflavones (10, 11 and 12, 13) by the formation of acetals by oxidative rearrangement of the protected chalcones (8 and 9) using Tl(NO3)3, followed by acid-catalyzed cyclization; (3) a final debenzylation by hydrogenolysis. 相似文献
66.
Structural analysis of a novel saccharide isolated from fermented beverage of plant extract 总被引:1,自引:0,他引:1
Okada H Fukushi E Yamamori A Kawazoe N Onodera S Kawabata J Shiomi N 《Carbohydrate research》2006,341(7):925-929
Fermented beverage of plant extract was prepared from about 50 kinds of vegetables and fruits. Natural fermentation was carried out mainly by lactic acid bacteria (Leuconostoc spp.) and yeast (Zygosaccharomyces spp. and Pichia spp.). Three kinds of saccharides have been found in this beverage and produced by fermentation. The saccharides isolated from the beverage using carbon-Celite column chromatography and preparative HPLC, were identified as a new saccharide, beta-d-fructopyranosyl-(2-->6)-d-glucopyranose, laminaribiose and maltose by examination of constituted sugars, GLC and GC-MS analyses of methyl derivatives and MALDI-TOF-MS and NMR measurements of the saccharides. 相似文献
67.
Kayama S Shigemoto N Kuwahara R Onodera M Yokozaki M Ohge H Kato F Hisatsune J Sugai M 《Journal of microbiological methods》2012,88(1):182-184
Klebsiella pneumoniae resistant to almost all ß-lactams except imipenem designated as ISMRK (imipenem-susceptible meropenem-resistant Klebsiella) is emerging in Japan. All ISMRK carries blaIMP-6 which differs from blaIMP-1 by only a single nucleotide at position 640. We devised a rapid detection system of blaIMP-6 by using ARMS PCR. 相似文献
68.
Bacteria of the genus Shigella are a major cause of death worldwide (L. von Seidlein et al., PLoS Med. 3:e353, 2006). We sequenced the genome of Shigella flexneri strain M90T Sm (serotype 5a) and compared it to the published genome sequence of S. flexneri strain 8401 (serotype 5b). 相似文献
69.
70.