首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   632篇
  免费   26篇
  国内免费   107篇
生物科学   765篇
  2023年   7篇
  2022年   10篇
  2021年   14篇
  2020年   17篇
  2019年   17篇
  2018年   6篇
  2017年   16篇
  2016年   11篇
  2015年   19篇
  2014年   6篇
  2013年   71篇
  2012年   20篇
  2011年   33篇
  2010年   27篇
  2009年   33篇
  2008年   40篇
  2007年   38篇
  2006年   38篇
  2005年   27篇
  2004年   31篇
  2003年   30篇
  2002年   25篇
  2001年   16篇
  2000年   18篇
  1999年   21篇
  1998年   20篇
  1997年   14篇
  1996年   15篇
  1995年   18篇
  1994年   20篇
  1993年   13篇
  1992年   9篇
  1991年   10篇
  1990年   13篇
  1989年   11篇
  1988年   5篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   5篇
  1983年   2篇
  1982年   4篇
  1981年   1篇
  1980年   3篇
  1979年   1篇
  1978年   4篇
  1977年   1篇
  1976年   1篇
排序方式: 共有765条查询结果,搜索用时 15 毫秒
1.
A mutant strain of Penicillium citrinum grown in a chemically-defined production medium, yielded 145 mg compactin l–1. The medium also facilitated spectrophotometric analysis of compactin. Addition of KH2PO4in the production medium did not increase the compactin production, while addition of a surfactant, Tween 80, increased compactin to 175 mg l–1. Inoculation with 107 spores ml–1 and initial pH of 6.5–7 were the most suitable for compactin production.  相似文献   
2.
A gene of Penicillium funiculosum encoding an endoglucanase was cloned and expressed in Escherichia coli using the lacZ promoter of vector pUC 18. The gene product hydrolyzed carboxymethyl cellulose and showed strong cross reactivity with P. funiculosum anticellulases.  相似文献   
3.
4.
Seven out of nine Penicillium isolates from mouldy maize in Yugoslavia have been differentiated into the adjacent species P. aurantiogriseum and P. commune. Nephrotoxicity of cultured mycelia in the rat has been demonstrated for all isolates of both species and was correlated usefully, though indirectly, with the production of benzodiazepine secondary metabolites, notably auranthine. Shredded wheat (22 g) moulded by an example of each species and fed to a rat over 4 days elicited renal pathology in the P3 segment of proximal tubules, involving frequent pyknosis and extensive mitosis typical of this as yet uncharacterised toxin. The effect was attributed in P. aurantiogriseum at least partly to the spores. Prominent pathology was elicited by only lg of spores given over 4 days.  相似文献   
5.
Investigations were carried out on the effects of Penicillium digitatum and Fusarium oxysporum on the nutritional value of pawpaw (Carica papaya). Decreases were observed in ash content, phosphorus, sodium, reducing sugars and ascorbic acid levels of fruits infected with P. digitatum, but increases in calcium and potassium content. In fruits infected by F. oxysporium, there were decreases in phosphorus, calcium, sodium ascorbic acid and reducing sugar levels; but the levels of ash content increased. The total protein level increased in the fruits infected with both fungi. These results revealed a reduction in fruit quality.  相似文献   
6.
Summary We cloned the Penicillium chrysogenum trpC gene from a genomic library by complementation of an Escherichia coli trpC mutant lacking phosphoribosylanthranilate isomerase activity. The gene ecodes a 2.7 kb poly(A)+ RNA. We localized the gene by sequence analysis in a 2.9 kb DNA insert found in the smallest plasmid selected from the library. Sequence data strongly suggest that the organization of the gene is similar to that described in other Ascomycetes. We found that a DNA fragment which codes only for the carboxy-terminal protion of the polypeptide is sufficient for complementation of the E. coli trpC9830 mutation.  相似文献   
7.
Two interesting microfungi are described as new to Japan:Talaromyces galapagensis (anam.Penicillium galapagense), isolated from soil in Shizuoka; andPenicillium megasporum, isolated from marine sludge in Nagasaki. Some observations are recorded, particularly on ascomatal initials ofT. galapagensis, which are similar to those described forTalaromyces flavus.(48): Kaneko, S., Mycoscience 36: 359–360, 1995.  相似文献   
8.
The major cuticular components of Indian tasar silkworm,Antheraea mylitta Drury, were sequentially extracted and estimated to ascertain preferential utilization of these components for growth by the entomopathogenic fungusPenicillium citrinum Thom. Proteins which constituted 61.64% dry weight of cuticule were found to play a key role in the growth ofP. citrinum whereas lipids (7.15%) and chitin (30.02%) were least involved. Also, this study suggests absence of any mycocidal substance in the cuticle ofA. mylitta.  相似文献   
9.
A new species ofTalaromyces (Ascomycetes; Trichocomaceae) with aPenicillium anamorph,T. lagunensis, is described and illustrated. This fungus is characterized by its extremely restricted growh on Czapek-yeast extract agar, light yellow to light orange ascomata with a telaperidium, catenate, pyriform or ellipsoidal asci, ellipsoidal or subglobose ascospores with a microtuberculate wall, short conidiophores with an irregular, mostly monoverticillate to biverticillate penicillus, and subglobose to ovoid conidia. The holotype was isolated from forest soil in the Philippines.  相似文献   
10.
Penicillium candidum grew and produced lipase in a culture medium supplemented with 0.2% olive oil. Significant enzyme production required the presence of olive, oil and was prevented by cycloheximide. Polyacrylamide gel electrophoresis of filtrates from olive oil fermentations gave a single band of lipase activity (MW 80 KDa). Among the olive oil components only oleate allowed significant lipase production. Other carboxylic and saturated fatty acids containing similar or lower numbers of carbon atoms, did not cause derepression of lipase formation.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号