全文获取类型
收费全文 | 2715篇 |
免费 | 159篇 |
国内免费 | 1篇 |
专业分类
2875篇 |
出版年
2022年 | 14篇 |
2021年 | 37篇 |
2020年 | 17篇 |
2019年 | 18篇 |
2018年 | 31篇 |
2017年 | 34篇 |
2016年 | 44篇 |
2015年 | 92篇 |
2014年 | 93篇 |
2013年 | 135篇 |
2012年 | 146篇 |
2011年 | 167篇 |
2010年 | 101篇 |
2009年 | 82篇 |
2008年 | 131篇 |
2007年 | 140篇 |
2006年 | 114篇 |
2005年 | 122篇 |
2004年 | 113篇 |
2003年 | 121篇 |
2002年 | 119篇 |
2001年 | 101篇 |
2000年 | 83篇 |
1999年 | 68篇 |
1998年 | 32篇 |
1997年 | 27篇 |
1996年 | 28篇 |
1995年 | 22篇 |
1994年 | 16篇 |
1993年 | 21篇 |
1992年 | 63篇 |
1991年 | 43篇 |
1990年 | 37篇 |
1989年 | 43篇 |
1988年 | 31篇 |
1987年 | 39篇 |
1986年 | 35篇 |
1985年 | 47篇 |
1984年 | 30篇 |
1983年 | 22篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 13篇 |
1979年 | 25篇 |
1975年 | 14篇 |
1974年 | 13篇 |
1973年 | 11篇 |
1972年 | 14篇 |
1971年 | 12篇 |
1970年 | 11篇 |
排序方式: 共有2875条查询结果,搜索用时 0 毫秒
981.
Shinobu Iriuchijima Atsuko Keiyu Natsuko Kojima 《Bioscience, biotechnology, and biochemistry》2013,77(6):1593-1597
Enzymes and microorganisms were screened for the enantioselective hydrolysis of (±)-1-acetoxy-2,3-dichloropropane (1) which is convertible to epichlorohydrin. Pancreatin and steapsin from hog pancreas were found to hydrolyze (±)-1 asymmetrically to give (S)-1 of 90% enantiomeric excess (e.e.). From (S)-1 was synthesized the optically pure (S)-isomer of propranolol[1-isopropylamino-3-(1-naphthoxy)-2-propanol], one of the typical β-adrenergic blocking agents. 相似文献
982.
983.
984.
985.
Yoshida H Arai S Hara KY Yamada R Ogino C Fukuda H Kondo A 《Applied microbiology and biotechnology》2011,89(5):1417-1422
Glutathione is a valuable tri-peptide that is widely used in the pharmaceutical, food, and cosmetic industries. Glutathione
is produced industrially by fermentation using Saccharomyces cerevisiae. We demonstrated that expression of amylase genes in glutathione-producing S. cerevisiae enables direct use of starch as a carbon source, thus eliminating the Crabtree effect that is caused by excess glucose. Consequently,
cell growth and glutathione productivity were significantly improved. This approach is potentially applicable to a variety
of fermentative processes for production of value-added chemicals under aerobic conditions. 相似文献
986.
987.
988.
989.
Spain E Kojima R Kaner RB Wallace GG O'Grady J Lacey K Barry T Keyes TE Forster RJ 《Biosensors & bioelectronics》2011,26(5):2613-2618
Polyaniline (PANI) nanofibres (PANI-NF) have been modified with chemically grown gold nanoparticles to give a nanocomposite material (PANI-NF-AuNP) and deposited on gold electrodes. Single stranded capture DNA was then bound to the gold nanoparticles and the underlying gold electrode and allowed to hybridise with a complementary target strand that is uniquely associated with the pathogen, Staphylococcus aureus (S. aureus), that causes mastitis. Significantly, cyclic voltammetry demonstrates that deposition of the gold nanoparticles increases the area available for DNA immobilisation by a factor of approximately 4. EPR reveals that the addition of the Au nanoparticles efficiently decreases the interactions between adjacent PANI chains and/or motional broadening. Finally, a second horseradish peroxidase (HRP) labelled DNA strand hybridises with the target allowing the concentration of the target DNA to be detected by monitoring the reduction of a hydroquinone mediator in solution. The sensors have a wide dynamic range, excellent ability to discriminate DNA mismatches and a high sensitivity. Semi-log plots of the pathogen DNA concentration vs. faradaic current were linear from 150×10(-12) to 1×10(-6) mol L(-1) and pM concentrations could be detected without the need for molecular, e.g., PCR or NASBA, amplification. 相似文献
990.
Nagai H Ebisu S Abe R Goto T Takahashi N Hosaka T Kawada T 《Bioscience, biotechnology, and biochemistry》2011,75(2):337-341
The activation of peroxisome-proliferator-activated receptor-γ (PPARγ), which plays a central role in adipocyte differentiation, depends on ligand-dependent co-activator recruitment. In this study, we developed a novel method of PPARγ ligand screening by measuring the increase in fluorescent polarization accompanied by the interaction of a fluorescent co-activator and PPARγ. Sterol receptor co-activator-1 (SRC-1), a major PPARγ co-activator, was probed by fluorescent TAMRA by the Amber codon fluorescence probe method. Polarization was increased by adding PPARγ ligands to a solution containing labeled SRC-1 (designated TAMRA-SRC-S) and PPARγ. The disassociation constants (Kd) of the PPARγ synthesized ligands, pioglitazone (221 nM), troglitazone (83.0 nM), and 15-deoxy-Δ12,14-prostaglandin J(2) (15d-ΔPGJ(2)) (156 nM), were determined by this method. Farnesol (2.89 μM) and bixin (21.1 μM), which we have reported to be PPARγ ligands, increased the fluorescent polarization. Their Kd values were in agreement with the ED(50) values obtained in the luciferase assay. The results indicate that the method is valuable for screening natural PPARγ ligands. 相似文献