全文获取类型
收费全文 | 400篇 |
免费 | 29篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 21篇 |
2015年 | 20篇 |
2014年 | 30篇 |
2013年 | 23篇 |
2012年 | 32篇 |
2011年 | 19篇 |
2010年 | 24篇 |
2009年 | 19篇 |
2008年 | 27篇 |
2007年 | 21篇 |
2006年 | 19篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 8篇 |
2002年 | 13篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有429条查询结果,搜索用时 15 毫秒
421.
Fabiano de A. Ximenes Fabiane Quirino de Paula Silveira Edivaldo Ximenes F. Filho 《Current microbiology》1996,33(2):71-77
Nine Trichoderma harzianum strains were screened for β-xylosidase activity when grown in solid-state cultures on media containing wheat bran as the
carbon source. All strains produced β-xylosidase activity, the most active being in extracts of cultures of T. harzianum strain 4. A β-xylosidase was purified by ammonium sulfate precipitation, ultrafiltration, gel filtration, and ion exchange
chromatography from solid-state cultures of T. harzianum strain C. Enzyme preparations yielded a single band when stained for protein following eletrophoresis. The molecular weight
value, calculated following SDS-PAGE, was determined to be 60 kDa. β-Xylosidase was most active at pH 4.0–4.5 and 70°C. This
enzyme had a K
m
value of 0.053 mM. The phenol-sulfuric acid method detected the presence of a small amount of carbohydrate in the purified
enzyme preparation. β-Xylosidase was active against some p-nitrophenylglycosides. The enzyme was inactive against xylan and PNPG. β-xylosidase activity was inhibited by xylose and
SDS. Iodoacetamide, dithiothreitol, gluconolactone, glucose, and mercuric chloride failed to inactivate this enzyme's activity.
A synergistic effect was observed when β-xylosidase from T. harzianum strain C and β-xylanase from Aspergillus fumigatus were incubated with pretreated arabinoxylan.
Received: 1 December 1995 / Accepted: 11 December 1995 相似文献
422.
Dartanh? J. Soares Fabiano B. Rocha Lidiane L. Duarte Robert W. Barreto 《Mycological Progress》2011,10(3):315-321
The new species Pyriculariopsis calatheae is described causing leaf spots on Calathea longifolia (Marantaceae). It represents an addition to the mycobiota of the tropical seasonal semi-deciduous montane forest, a component
of the Brazilian Atlantic forest and a highly threatened ecosystem. 相似文献
423.
424.
Steve Ahlswede Ezequiel Chimbioputo Fabiano Derek Keeping Klaus Birkhofer 《African Journal of Ecology》2019,57(2):177-189
Finding an appropriate method to monitor a wide range of mammal species simultaneously is notoriously difficult, as each method has its limitations. Here, we examine a formula, known as the Formozov–Malyshev–Pereleshin (FMP), which uses mean daily travel distances (day ranges) to convert spoor counts into density estimates. Availability of accurate estimates of day ranges is a limitation of the FMP formula. Here, we used allometry to estimate day ranges for those species that lacked empirical movement data and general additive models (GAM) to assess trends in density estimates. With this approach, we derived density estimates for 10 mammal species, regardless of whether they were abundant, or rare and elusive (e.g. carnivores). General additive models suggest that six species are stable or increasing, and four declining, although all nonsignificantly. Use of allometric estimates in lieu of empirical estimates led to falsely increased precision in density estimates, highlighting the need to fill the knowledge gap in movement ecology for certain species. Simulations were used to examine error introduced into trend estimates by this bias. We conclude that the FMP formula, when properly employed, can be an efficient method for simultaneous monitoring of multispecies in different functional groups. 相似文献
425.
426.
Larissa Luz Gomes Fabiano Cordeiro Moreira Igor Guerreiro Hamoy Sidney Santos Paulo Assump??o ádamo L. Santana ?ndrea Ribeiro-dos-Santos 《Bioinformation》2014,10(5):246-250
In this paper, an unsupervised artificial neural network was implemented to identify the patters of specific signatures. The network
was based on the differential expression of miRNAs (under or over expression) found in healthy or cancerous gastric tissues.
Among the tissues analyzes, the neural network evaluated 514 miRNAs of gastric tissue that exhibited significant differential
expression. The result suggested a specific expression signature nine miRNAs (hsa-mir-21, hsa-mir-29a, hsa-mir-29c, hsa-mir-148a,
hsa-mir-141, hsa-let-7b, hsa-mir-31, hsa-mir-451, and hsa-mir-192), all with significant values (p-value < 0.01 and fold change > 5) that
clustered the samples into two groups: healthy tissue and gastric cancer tissue. The results obtained “in silico” must be validated in
a molecular biology laboratory; if confirmed, this method may be used in the future as a risk marker for gastric cancer
development. 相似文献
427.
428.
429.
Anapaula Sommer Vinagre Ana Paula Nunes do Amaral Fabiana Pinto Ribarcki Eliane Fraga da Silveira Eduardo Prico 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,146(4):514
The aim of this study was to analyze the seasonal variations of carbohydrate and lipid metabolism of the ghost crab Ocypode quadrata (Fabricius, 1787) on a sandy beach in the southern region of Brazil. Crabs and hemolymph samples were collected monthly in the field. Hepatopancreas, gills, gonads and claw muscles were used for glycogen determination. In males, blood glucose levels increased in the summer and in the winter. The glycogen values increased significantly in the hepatopancreas in the winter, but remained constant in the muscle, gonads and gills. In females, hemolymph glucose levels, glycogen values in the hepatopancreas and in the gills remained constant throughout the year; however, muscular glycogen increased in the spring and gonad glycogen decreased in the summer. Hemolymph triglyceride levels of males and females and total cholesterol of males decreased significantly in the spring. In females, a significant increase of total cholesterol levels was found in the winter. The findings suggest that in O. quadrata lipids seem to be an important reserve of energy used during reproduction, both in males and females, while glycogen may be used during periods of intense activity or fasting. 相似文献