全文获取类型
收费全文 | 227篇 |
免费 | 1篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 8篇 |
环保管理 | 5篇 |
综合类 | 90篇 |
基础理论 | 60篇 |
环境理论 | 1篇 |
污染及防治 | 50篇 |
评价与监测 | 5篇 |
社会与环境 | 4篇 |
出版年
2021年 | 3篇 |
2016年 | 2篇 |
2013年 | 9篇 |
2012年 | 13篇 |
2011年 | 5篇 |
2010年 | 8篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 13篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 9篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 5篇 |
1965年 | 4篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1962年 | 4篇 |
1961年 | 2篇 |
1960年 | 7篇 |
1959年 | 4篇 |
1958年 | 2篇 |
1957年 | 2篇 |
1955年 | 5篇 |
1954年 | 1篇 |
排序方式: 共有230条查询结果,搜索用时 15 毫秒
151.
Srividya Iyer Ruchir Shah Ashima Sharma Dieter Jendrossek Anjana Desai 《Journal of Polymers and the Environment》2000,8(4):197-203
The extracellular poly(-hydroxybutyrate) (PHB) depolymerase of Aspergillus fumigatus Pdf1 was purified by a new, simple, one-step affinity chromatography method using the substrate PHB. The purified enzyme was glycosylated, with the molecular mass of 40 KD, and exhibited a novel self-aggregation behavior by means of hydrophobic interaction that was resolved by Triton X-100 (TX-100) pretreatment of enzyme and also TX-100 incorporation in the native gel. The apparent K
m value of purified enzyme for PHB was 119 g/mL and 3-hydroxybutyrate was detected as the main endproduct of PHB hydrolysis. The depolymerase was insensitive to phenylmethyl sulfonyl fluoride (PMSF), sodium azide, ethylenediaminetetraacetic acid (EDTA), and para-chloromercuric benzoic acid (PCMB), but was inactivated by dithioerythritol (DTT) and showed specificity for short chain-length poly(-hydroxyalkanoates) (PHAs) such as PHB, poly(hydroxyvalerate) (PHV), and copolymers of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). Medium-chain-length PHA failed to get hydrolyzed. The enzyme, however, exhibited strong cross reactivity with the Comamonas sp. PHB depolymerase antibodies, but not with PHV depolymerase antibodies of Pseudomonas lemoignei. Southern hybridization and dot blot analysis of A. fumigatus Pdf1 genomic DNA with alkaline phosphatase labeled probes of P. lemoignei PHB and PHV depolymerase genes revealed no homology, although the enzyme hydrolyzed both PHB and PHV. 相似文献
152.
Biodegradation behavior and material properties of aliphatic/aromatic polyesters of commercial importance 总被引:2,自引:0,他引:2
Uwe Witt Rolf- Joachim Müller Wolf- Dieter Deckwer 《Journal of Polymers and the Environment》1997,5(2):81-89
Copolyesters of aliphatic monomers with a defined amount of terephthalic acid recently have been shown to be biodegradable.
This group of plastic materials exhibits very interesting material properties with regard to their technical application potential.
A tensile strength of 25 N/mm2 combined with elongations at break up to 1500% was achieved for BTA materials. Melting points varied from 80 to 140‡C. Biodegradation
rate under compositing conditions were determined, showing typical erosion rates of films, in the range of 5 to 10 Μm/week.
The material properties and the degradation rate as well can be adjusted by the copolymer composition. Stretching of the polymer
in the cold state leads to 10-fold higher mechanical strength of the material. The polyester chain can be extended to high
molar masses, resulting in melt viscosities suitable, e.g., for melt below extrusion. 相似文献
153.
154.
155.
156.
157.
158.
159.
160.