全文获取类型
收费全文 | 627篇 |
免费 | 35篇 |
出版年
2023年 | 9篇 |
2022年 | 10篇 |
2021年 | 29篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 25篇 |
2017年 | 32篇 |
2016年 | 35篇 |
2015年 | 36篇 |
2014年 | 47篇 |
2013年 | 49篇 |
2012年 | 55篇 |
2011年 | 69篇 |
2010年 | 34篇 |
2009年 | 30篇 |
2008年 | 28篇 |
2007年 | 20篇 |
2006年 | 24篇 |
2005年 | 17篇 |
2004年 | 15篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1968年 | 1篇 |
排序方式: 共有662条查询结果,搜索用时 62 毫秒
571.
Production of biogas in batch digesters at 30°C from sheep droppings produced 93 l gas/kg dry matter whereas cattle dung yielded 234 l/kg dry matter. When the sheep droppings and cattle dung were used at 25:75 (w/w), gas production per kg dry matter was equal to that of cattle dung only. The methane content of the biogas obtained from sheep droppings was 70 to 72% as compared to 56 to 60% from cattle dung. 相似文献
572.
Shamsher Singh Kanwar Hemant Kumar Verma Rajeev Kumar Kaushal Reena Gupta Swapandeep Singh Chimni Yogesh Kumar Ghansham Singh Chauhan 《World journal of microbiology & biotechnology》2005,21(6-7):1037-1044
Summary A purified alkaline thermo-tolerant bacterial lipase from Pseudomonas aeruginosa BTS-2 was immobilized on a poly (AAc-co-HPMA-cl-MBAm) hydrogel network. The hydrogel showed approximately 95% binding efficiency for lipase (specific activity 1.96 U mg−1). The immobilized enzyme achieved 65.1% conversion of ethanol and propionic acid (100 mM each) into ethyl propionate in n-nonane at 65 °C in 9 h. When alkane of C-chain length lower than n-nonane was used as the organic solvent, the conversion of ethanol and propionic acid into ethyl propionate decreased with
a decrease in the log P value of alkanes. The immobilized lipase retained approximately 30% of its original catalytic activity after five cycles
of reuse for esterification of ethanol and propionic acid into ethyl propionate at temperature 65 °C in 3 h. Addition of a
molecular sieve (3 ?) to the reaction mixture enhanced the formation of ethyl propionate to 89.3%. Moreover, ethanol and propionic
acid when taken a molar ratio of 3:1 further promoted the conversion rate to 94%. However, an increase in the molar ratio
of propionic acid with respect to ethanol resulted in a decline of ethyl propionate synthesis. 相似文献
573.
Pooja Sharma Hansi Kumari Mukesh Kumar Mansi Verma Kirti Kumari Shweta Malhotra Jitendra Khurana Rup Lal 《Indian journal of microbiology》2008,48(2):173-194
In the last 20 years, the applications of genomics tools have completely transformed the field of microbial research. This
has primarily happened due to revolution in sequencing technologies that have become available today. This review therefore,
first describes the discoveries, upgradation and automation of sequencing techniques in a chronological order, followed by
a brief discussion on microbial genomics. Some of the recently sequenced bacterial genomes are described to explain how complete
genome data is now being used to derive interesting findings. Apart from the genomics of individual microbes, the study of
unculturable microbiota from different environments is increasingly gaining importance. The second section is thus dedicated
to the concept of metagenomics describing environmental DNA isolation, metagenomic library construction and screening methods
to look for novel and potentially important genes, enzymes and biomolecules. It also deals with the pioneering studies in
the area of metagenomics that are offering new insights into the previously unappreciated microbial world.
The authors have contributed equally to the work 相似文献
574.
Rup Lal Mandeep Dadhwal Kirti Kumari Pooja Sharma Ajaib Singh Hansi Kumari Simran Jit Sanjay Kumar Gupta Aeshna Nigam Devi Lal Mansi Verma Jaspreet Kaur Kiran Bala Swati Jindal 《Indian journal of microbiology》2008,48(1):3-18
The unusual process of production of hexachlorocyclohexane (HCH) and extensive use of technical HCH and lindane has created
a very serious problem of HCH contamination. While the use of technical HCH and lindane has been banned all over the world,
India still continues producing lindane. Bacteria, especially Sphingomonads have been isolated that can degrade HCH isomers.
Among all the bacterial strains isolated so far, Sphingobium indicum B90A that was isolated from HCH treated rhizosphere soil appears to have a better potential for HCH degradation. This conclusion
is based on studies on the organization of lin genes and degradation ability of B90A. This strain perhaps can be used for HCH decontamination through bioaugmentation. 相似文献
575.
576.
577.
Kanwar N Fayyazi A Backofen B Nitsche M Dressel R von Mollard GF 《Cell and tissue research》2008,334(2):227-242
SNARE (soluble-N-ethylmaleimide-sensitive factor attachment receptor) proteins mediate the recognition and fusion of transport vesicles in
eukaryotic cells. The SNARE protein VAMP8 (also called endobrevin) is involved in the fusion of late endosomes and in some
pathways of regulated exocytosis. In a subset of mice deficient for the SNARE protein VAMP8, a severe alteration of the thymus
and in T lymphocyte development was observed and characterized. The size of the thymus and the number of thymocytes were dramatically
reduced compared with those in heterozygous littermates. Further, the compartmentalization into cortex and medulla and the
organization of the thymus epithelium were disturbed. The numbers of all thymocyte subpopulations were reduced, with the CD4
and CD8 double-positive thymocytes being most severely affected. The proportion of proliferating thymocytes was reduced, and
the staining of apoptotic cells in situ and ex vivo indicated an increased number of apoptotic cells. Isolated thymocytes of Vamp8
−/− mice were more susceptible to various apoptotic stimuli including glucocorticoids, FAS receptor, and CD3/CD28-mediated signaling
in vitro, even before an increased number of apoptotic cells was detectable in situ. However, bone marrow of phenotypically
affected Vamp8
−/− mice was readily able to repopulate immunodeficient hosts suggesting that the SNARE protein VAMP8 has a specific function
in the thymic stroma affecting the proliferation and apoptosis of T lymphocytes during maturation in the thymus.
This work was supported by a Georg Christoph Lichtenberg Stipend from the Ministry for Science and Culture of Lower Saxony
(to N.K.) and in part by grant MRTN-CT-2004-512253 (TRANS-NET) from the European Union (to R.D.). 相似文献
578.
579.
A hyper-thermostable, alkaline lipase from Pseudomonas sp. with the property of thermal activation 总被引:1,自引:0,他引:1
A hyper-thermostable, alkaline lipase from a newly-isolated, mesophilic Pseudomonas sp. was optimal at pH 11 and at 90 °C. It had a half-life of more than 13 h at 90 °C. It was activated by 30% when heated at 90 °C for 2 h. The enzyme had a greater affinity for mustard oil (K
m=40 mg ml–1) than for olive oil (K
m=140 mg ml–1). 相似文献
580.
Kanwar SS Ghazi IA Chimni SS Joshi GK Rao GV Kaushal RK Gupta R Punj V 《Protein expression and purification》2006,46(2):421-428
A novel extra-cellular lipase from Bacillus coagulans MTCC-6375 was purified 76.4-fold by DEAE anion exchange and Octyl Sepharose chromatography. The purified enzyme was found to be electrophoretically pure by denaturing gel electrophoresis and possessed a molecular mass of approximately 103 kDa. The lipase was optimally active at 45 degrees C and retained approximately 50% of its original activity after 20 min of incubation at 55 degrees C. The enzyme was optimally active at pH 8.5. Mg2+, Cu2+, Ca2+, Hg2+, Al3+, and Fe3+ at 1mM enhanced hydrolytic activity of the lipase. Interestingly, Hg2+ ions resulted in a maximal increase in lipase activity but Zn2+ and Co2+ ions showed an antagonistic effect on this enzyme. EDTA at 150 mM concentration inhibited the activity of lipase but Hg2+ or Al3+ (10mM) restored most of the activity of EDTA-quenched lipase. Phenyl methyl sulfonyl fluoride (PMSF, 15 mM) decreased 98% of original activity of lipase. The lipase was more specific to p-nitrophenyl esters of 8 (pNPC) and 16 (pNPP) carbon chain length esters. The lipase had a Vmax and Km of 0.44 mmol mg(-1)min(-1) and 28 mM for hydrolysis of pNPP, and 0.7 mmol mg(-1)min(-1) and 32 mM for hydrolysis of pNPC, respectively. 相似文献