全文获取类型
收费全文 | 390篇 |
免费 | 9篇 |
国内免费 | 30篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 47篇 |
2012年 | 5篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 19篇 |
2008年 | 10篇 |
2007年 | 19篇 |
2006年 | 21篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 19篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 6篇 |
1973年 | 1篇 |
排序方式: 共有429条查询结果,搜索用时 15 毫秒
101.
Caroline Michel Claire Bény Fabian Delorme Laurence Poirier Pauline Spolaore Dominique Morin Patrick d’Hugues 《Applied microbiology and biotechnology》2009,82(2):371-378
In this study, we investigate exopolysaccharide production by a bacterial consortium during the bioleaching of a cobaltiferrous
pyrite. Whereas comparable studies have looked at exopolysaccharide production in batch systems, this study focuses on a continuous
system comprising a series of four stirred bioreactors and reveals the difficulties in quantifying biomolecules in complex
media such as bioleached samples. We also adapted the phenol/sulphuric acid method to take into account iron interference,
thus establishing a new protocol for sugar quantification in bioleached samples characterised by low pH (1.4) and high iron
concentration (2 g l−1). This allows sugar analysis without any prior sample preparation step; only a small amount of sample is needed (0.5 ml)
and sample preparation is limited to a single filtration step. We found that free exopolysaccharides represented more than
80% of the total sugars in the bioreactors, probably because stirring creates abrasive conditions and detaches sugars bound
to pyrite or bacteria and that they were produced mainly in the first two reactors where bioleaching activity was greatest.
However, we could not establish any direct link between the measured exopolysaccharide concentration and bioleaching activity.
Exopolysaccharides could have another role (protection against stress) in addition to that in bacterial attachment. 相似文献
102.
Liliana Gianfreda Giuseppina Iamarino Rosalia Scelza Maria A. Rao 《Biocatalysis and Biotransformation》2006,24(3):177-187
Phenolics are often produced as wastes by several industrial and agricultural activities. Many of these compounds and their derivatives are extremely dangerous to living organisms, because they are highly toxic and thus represent a serious environmental concern.
Conventional remediation methods of phenol-polluted systems have some disadvantages due to high cost, time-consuming procedures and formation of toxic residues. Conversely, the use of oxidative catalysts, both enzymatic or inorganic, is a promising alternative technology to address the clean up of such wastes. Oxidative enzymes and inorganic compounds, both naturally occurring in soil, behave as biotic and abiotic catalysts and support the transformation of phenolic compounds. The complete mineralization of phenolic pollutants as well as the formation of polymeric products, often less toxic than their precursors, may occur.
The present paper gives a brief review of many aspects concerning the properties of biotic and abiotic catalytic agents effective in the transformation of phenolic compounds. The main mechanisms of the processes as well as their feasibility for catalytic practical applications will be addressed. Examples of their potentiality in the detoxification of phenol-polluted systems will be provided, as well. 相似文献
Conventional remediation methods of phenol-polluted systems have some disadvantages due to high cost, time-consuming procedures and formation of toxic residues. Conversely, the use of oxidative catalysts, both enzymatic or inorganic, is a promising alternative technology to address the clean up of such wastes. Oxidative enzymes and inorganic compounds, both naturally occurring in soil, behave as biotic and abiotic catalysts and support the transformation of phenolic compounds. The complete mineralization of phenolic pollutants as well as the formation of polymeric products, often less toxic than their precursors, may occur.
The present paper gives a brief review of many aspects concerning the properties of biotic and abiotic catalytic agents effective in the transformation of phenolic compounds. The main mechanisms of the processes as well as their feasibility for catalytic practical applications will be addressed. Examples of their potentiality in the detoxification of phenol-polluted systems will be provided, as well. 相似文献
103.
Degradation of xenobiotics in a partitioning bioreactor in which the partitioning phase is a polymer
Two-phase partitioning bioreactors (TPPBs) are characterized by a cell-containing aqueous phase and a second immiscible phase that contains toxic and/or hydrophobic substrates that partition to the cells at subinhibitory levels in response to the metabolic demand of the organisms. To date, the delivery phase in TPPBs has been a hydrophobic solvent that traditionally needed to possess a variety of important properties including biocompatibility, nonbioavailability, low volatility, and low cost, among others. In the present work we have shown that the organic solvent phase can be replaced by inexpensive polymer beads that function in a similar fashion as organic solvents, delivering a toxic substrate to cells based on equilibrium considerations. Specifically, 3.4 mm diameter beads of poly(ethylene-co-vinyl acetate) (EVA) were used to reduce the aqueous concentration of phenol in a bioreactor from toxic levels ( approximately 2,000 mg/L) to subinhibitory levels ( approximately 750 mg/L), after which Pseudomonas putida ATCC 11172 was added to the system and allowed to consume the total phenol loading. Thus, the beads absorbed the toxic substrate and released it to the cells on demand. The EVA beads, which could be reused, were able to absorb 14 mg phenol/g EVA. This work has opened the possibility of using widely mixed cultures in TPPB systems without concern for degradation of the delivery material and without concern of contamination. 相似文献
104.
A mixed culture aerobically metabolized phenol, cresol isomers (o-,m-,p-), 2-ethylphenol and xylenol isomers (2,5-DMP and 3,4-DMP) as the sole carbon and energy source. This culture had a high tolerance towards phenol with values of maximum degradation rate (V\max) of 47 M phenol mg–1 protein h–1 and inhibition substrate constant (Ki) of 10 mM. These kinetic parameters were considerably diminished and the toxicity increased with the alkylphenols. For example with 2,5-xylenol, V\max and Ki values of 0.8 M 2,5-xylenol mg–1 protein h–1 and 1.3 mM, respectively, were obtained. The cresols were 5-fold more toxic than phenol, whereas 2-ethylphenol and 3,4-xylenol were 11-fold more toxic, and 2,5-xylenol was 34-fold more toxic than phenol. 相似文献
105.
The treatment of olive oil mill wastewater (OMW) with two phenol resistant algae, Ankistrodesmus braunii and Scenedesmus quadricauda, showed a limited reduction of phenol content after 5 d of treatment, irrespective of algal concentration. Otherwise, cultures of both algae, grown in the dark, degraded over 50% of the low molecular weight phenols contained in OMW, but they were not completely removed, but were biotransformed into other non-identified, aromatic compounds. 相似文献
106.
107.
Degradation of phenol and phenolic compounds by a defined denitrifying bacterial culture 总被引:3,自引:0,他引:3
Thomas Swapna Sarfaraz Sami Mishra L.C. Iyengar Leela 《World journal of microbiology & biotechnology》2002,18(1):57-63
Phenol, a major pollutant in several industrial waste waters is often used as a model compound for studies on biodegradation. This study investigated the anoxic degradation of phenol and other phenolic compounds by a defined mixed culture of Alcaligenes faecalis and Enterobacter species. The culture was capable of degrading high concentrations of phenol (up to 600 mg/l) under anoxic conditions in a simple minimal mineral medium at an initial cell mass of 8 mg/l. However, the lag phase in growth and phenol removal increased with increase in phenol concentration. Dissolved CO2 was an absolute requirement for phenol degradation. In addition to nitrate, nitrite and oxygen could be used as electron acceptors. The kinetic constants, maximum specific growth rate max; inhibition constant, K
i and saturation constant, K
s were determined to be 0.206 h–1, 113 and 15 mg phenol/l respectively. p-Hydroxybenzoic acid was identified as an intermediate during phenol degradation. Apart from phenol, the culture utilized few other monocyclic aromatic compounds as growth substrates. The defined culture has remained stable with consistent phenol-degrading ability for more than 3 years and thus shows promise for its application in anoxic treatment of industrial waste waters containing phenolic compounds. 相似文献
108.
Abd-El-Haleem D Ripp S Scott C Sayler GS 《Journal of industrial microbiology & biotechnology》2002,29(5):233-237
A bioluminescent reporter strain, Acinetobacter sp. DF4-8, was constructed for the detection of phenol by inserting a mopR-like promoter upstream of the Vibrio fischeri bioluminescent luxCDABE gene cassette in a modified mini-Tn5 construct. When introduced into the chromosome of Acinetobacter sp. DF4, the bioreporter produced a sensitive bioluminescent response to phenol at concentrations ranging from 2.5 to 100
ppm. This response was linear (R
2=0.986) in the range from 20 to 90 ppm. A significant bioluminescent response was also recorded when strain DF4-8 was incubated
with slurries from aged, phenol-contaminated soil.
Received 13 February 2002/ Accepted in revised form 11 July 2002 相似文献
109.
A new phenol alloside, p-hydroxyphenyl β-D-alloside, has been isolated from the leaves of Viburnum wrightii in addition to several known compounds. The structures were elucidated by spectroscopic and chemical methods. 相似文献
110.
Byung‐Hyuk Kim Hee‐Mock Oh Young‐Ki Lee Gang‐Guk Choi Chi‐Yong Ahn Byung‐Dae Yoon Hee‐Sik Kim 《Journal of phycology》2006,42(5):1137-1141
A simple and rapid method is presented for the preparation of RNA from various cyanobacteria. Unlike other methods that require a lysis solution, lysozymes, or proteinase K, the proposed method, called the bead–phenol–chloroform (BPC) method, uses silica/zirconia beads, phenol, and chloroform to break the cells and extract RNA more efficiently. Experiments confirm that the BPC method can successfully isolate total RNA from various cyanobacterial strains without DNA contamination, and the extracted RNA samples have a relatively high purity, concentration, and yield. Furthermore, the BPC method is more rapid, simple, and economical when compared with previously reported methods. 相似文献