全文获取类型
收费全文 | 176篇 |
免费 | 7篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 11篇 |
2014年 | 11篇 |
2013年 | 18篇 |
2012年 | 18篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1997年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有183条查询结果,搜索用时 31 毫秒
101.
102.
103.
Exposure to high temperatures affects the photosynthetic processes in marine benthic microalgae by limiting the transport
of electrons, thus reducing the ability of the cell to use light. This causes damage to the Photosystem II (PSII) and may
lead to photoinhibition. However, the PSII of benthic microalgal communities from Brown Bay, eastern Antarctica, were relatively
unaffected by significant changes in temperature. Benthic microalgae exposed to temperatures up to 8°C and an irradiance of
450 μmol photons m−2 s−1 did not experience any photosynthetic damage or irreversible photoinhibition. The effective quantum yield (∆F/F
m′) at 8°C (0.433 ± 0.042) was higher by comparison to cell incubated at −0.1°C (0.373 ± 0.015) with similar irradiances. Temperatures
down to −5°C at a similar irradiance showed a decrease in photosynthesis with decreasing temperature, but no severe photoinhibition
as the cells were able to dissipate excess energy via non-photochemical quenching and recover from damage. These responses
are consistent with those recorded in past studies on Antarctic benthic microalgae and suggest that short-term temperature
change (from −5 to 8°C) will not do irreversible damage to the PSII and will not affect the photosynthesis of the benthic
microalgae. 相似文献
104.
Thirty samples consisting of wheat (15) and barley (15) were collected from different markets in Penang, Malaysia, originating from India and Thailand, respectively. All samples were analyzed for occurrence of Aspergillus spp. and aflatoxin B1 (AFB1). Aspergillus flavus was dominant in all samples followed by A. niger. AFB1 could be detected in three wheat samples ranging from 0.42 to 1.89 μg/kg and one barley sample had 0.58 μg/kg of AFB1. The AFB1 levels in all the samples were below the Malaysian regulatory limits (<35 μg/kg). The frequency and quantity of AFB1 levels in this study were very low in wheat and barley samples compared to other agricultural commodities reported in India and Thailand. This is the first report on determination of Aspergillus spp. and AFB1 in imported wheat and barley grains in Penang, Malaysia. 相似文献
105.
Salleh HM Müllegger J Reid SP Chan WY Hwang J Warren RA Withers SG 《Carbohydrate research》2006,341(1):49-59
The putative beta-glucuronidase from Thermotoga maritima, comprising 563 amino acid residues conjugated with a Hisx6 tag, was cloned and expressed in Escherichia coli. The enzyme has a moderately broad specificity, hydrolysing a range of p-nitrophenyl glycoside substrates, but has greatest activity on p-nitrophenyl beta-D-glucosiduronic acid (kcat=68 s(-1), kcat/K(M)= 4.5x10(5) M(-1) s(-1)). The enzyme also shows a relatively broad pH-dependence with activity from pH4.5 to 7.5 and a maximum at pH6.5. As expected the enzyme is stable towards heat denaturation, with a half life of 3h at 85 degrees C, in contrast to the mesophilic E. coli enzyme, which has a half life of 2.6h at 50 degrees C. The identity of the catalytic nucleophile was confirmed as Glu476 within the sequence VTEFGAD by trapping the glycosyl-enzyme intermediate using the mechanism-based inactivator, 2-deoxy-2-fluoro-beta-D-glucosyluronic acid fluoride and identifying the labeled peptide in peptic digests by HPLC-MS/MS methodologies. Consistent with this, the Glu476Ala mutant was shown to be hydrolytically inactive. The acid/base catalyst was confirmed as Glu383 by generation and kinetic analysis of enzyme mutants modified at that position, Glu383Ala and Glu383Gln. The demonstration of activity rescue by azide is consistent with the proposed role for this residue. This enzyme therefore appears suitable for use in enzymatic oligosaccharide synthesis in either the transglycosylation mode or by use of glycosynthase and thioglycoligase approaches. 相似文献
106.
Mohd. Basyaruddin Abdul Rahman Azizah Misran Mahiran Basri Raja Noor Zaliha Raja Abdul Rahman Abu Bakar Salleh Habibah Abdul Wahab 《Biocatalysis and Biotransformation》2005,23(3):211-216
A detailed study of the trypsin surface has been carried out to gain insight into its biological functions and interactions which helped to determine the binding specificity. Twenty-four cavity pockets were automatically identified on trypsin from PDB file entry 1AUJ using CASTp (Computed Atlas of Surface Topography of proteins). Molecular docking was exploited as an efficient in silico screening tool for studying protein-ligand interactions. A systematic docking study using Autodock 3.05 has been performed on the five largest binding pockets in trypsin. A set of ten putative chemical ligands was used to dock into selected binding pockets. Docking of ligands into the five largest pockets in trypsin showed that 1,10-phenanthroline and ethanolamine preferentially bound at pocket 24 and benzamidine at pocket 22. Thermodynamically, we also found that ethanol, propanol, propandiol and phosphoethanolamine preferentially bound at pocket 21 whereas p-aminobenzamidine, phenylacetic acid and phenylalanine interacted mainly at pocket 20 based on their lowest interaction free energy. 相似文献
107.
Maizirwan Mel Abdul Rafiz Abdul Rahman Mohamad Ramlan Mohamed Salleh Yumi Zuhanis Has-Yun Hashim 《World journal of microbiology & biotechnology》2008,24(9):1923-1927
The study was done to improve the viability of the RC1 hybridoma cell in order to produce more amount of monoclonal antibody
(mAb). By using the optimized media, the cell had been cultured in two bioreactor systems which were the MiniPerm and Stirred
Tank bioreactor (ST bioreactor), and the results were compared to the one obtained by using the T-Flask bioreactor which was
used as a standard. The results showed that the ST bioreactor was able to improve the viability of the cell to the value of
91.8% which was a little bit better than the one obtained by the MiniPerm bioreactor (88.6%) and far better than that of achieved
by the T-Flask bioreactor (76.4%). This was well correlated with the good growth performance of the cell in the ST bioreactor
with the specific growth rate (μ) value of 0.0289 h−1 followed by MiniPerm bioreactor with the value of 0.0243 h−1 and then the T-Flask with the value of 0.0151 h−1. The low value of doubling time (t
d
) obtained in the ST bioreactor (24 h) compared to the one obtained in the MiniPerm (29 h) and T-Flask bioreactor (46 h) had
also contributed to the higher value of cell viability. As a result a higher concentration of mAb was able to be produced
by the ST bioreactor (0.42 g l−1) compared to that of the MiniPerm (0.37 g l−1) and T-Flask bioreactor (0.23 g l−1). 相似文献
108.
Barkman TJ Bendiksby M Lim SH Salleh KM Nais J Madulid D Schumacher T 《Current biology : CB》2008,18(19):1508-1513
Evolutionary theory explains phenotypic change as the result of natural selection, with constraint limiting the direction, magnitude, and rate of response [1]. Constraint is particularly likely to govern evolutionary change when a trait is at perceived upper or lower limits. Macroevolutionary rates of floral-size change are unknown for any angiosperm family, but it is predicted that rates should be diminished near the upper size limit of flowers, as has been shown for mammal body mass [2]. Our molecular results show that rates of floral-size evolution have been extremely rapid in the endoholoparasite Rafflesia, which contains the world's largest flowers [3]. These data provide the first estimates of macroevolutionary rates of floral-size change and indicate that in this lineage, floral diameter increased by an average of 20 cm (and up to 90 cm)/million years. In contrast to our expectations, it appears that the magnitude and rate of floral-size increase is greater for lineages with larger flowered ancestors. This study suggests that constraints on rates of floral-size evolution may not be limiting in Rafflesia, reinforcing results of artificial- and natural-selection studies in other plants that demonstrated the potential for rapid size changes [4-6]. 相似文献
109.
110.