全文获取类型
收费全文 | 215篇 |
免费 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 13篇 |
2019年 | 16篇 |
2018年 | 11篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 23篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1977年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有227条查询结果,搜索用时 156 毫秒
221.
222.
Pooria Gill Bijan Ranjbar Reza Saber Khosro Khajeh Mehdi Mohammadian 《Journal of biomolecular techniques》2011,22(2):60-66
Cauliflower-like DNAs are stem-loop DNAs that are fabricated periodically in inverted repetitions from deoxyribonucleic acid phosphates (dNTPs) by loop-mediated isothermal amplification (LAMP). Cauliflower-like DNAs have ladder-shape behaviors on gel electrophoresis, and increasing the time of LAMP leads to multiplying the repetitions, stem-loops, and electrophoretic bands. Cauliflower-like DNAs were fabricated via LAMP using two loop primers, two bumper primers, dNTPs, a λ-phage DNA template, and a Bst DNA polymerase in 75- and 90-min periods. These times led to manufacturing two types of cauliflower-like DNAs with different contents of inverted repetitions and stem-loops, which were clearly indicated by two comparable electrophoresis patterns in agarose gel. LAMP-fabricated DNAs and natural dsB-DNA (salmon genomic DNA) were dialyzed in Gomori phosphate buffer (10 mM, pH 7.4) to be isolated from salts, nucleotides, and primers. Dialyzed DNAs were studied using UV spectroscopy, circular dichroism spectropolarimetry, and fluorescence spectrophotometry. Structural analyses indicated reduction of the molecular ellipticity and extinction coefficients in comparison with B-DNA. Also, cauliflower-like DNAs demonstrated less intrinsic and more extrinsic fluorescence in comparison with natural DNA. The overwinding and lengthening of the cauliflower-like configurations of LAMP DNAs led to changes in physical parameters of this type of DNA in comparison with natural DNA. The results obtained introduced new biomolecular characteristics of DNA macromolecules fabricated within a LAMP process and show the effects of more inverted repeats and stem-loops, which are manufactured by lengthening the process. 相似文献
223.
Abstract. Both dorsal body tissue extracts and dorsal body-conditioned medium stimulated in vitro polysaccharide synthesis in albumen gland explants in Helisoma duryi . This activity is heat- and protease-resistant. Dorsal body tissue extracts and dorsal body-conditioned medium were passed through solid-phase extraction cartridges, then eluted with increasing concentrations of methanol (20%, 70%, and 100%) and the various eluates tested for their biological activity. An active factor was found in the 100% methanol wash from both dorsal body tissue extracts and the conditioned medium. In addition, another bioactive factor in the conditioned medium eluted with 70% methanol. The endocrine dorsal bodies in the freshwater snail H. duryi were maintained in vitro , and following incubation, the culture medium was collected and tested for the presence of ecdysteroids. Radioimmunoassay of the culture medium demonstrated the presence of ecdysteroid-like immunoreactivity, suggesting the dorsal bodies are capable of secreting ecdysteroids in vitro . Identification of released ecdysteroids by HPLC/RIA revealed a number of immunoreactive fractions, which were tested for bioactivity. To test for possible physiological functions of ecdysteroids in Helisoma duryi , 20-hydroxyecdysone (a potent ecdysteroid in arthropods) was injected into non-egg laying (virgin) snails. Injections of ecdysteroid induced low egg-laying activity and the maturation of oocytes in the ovotestis. Incubation of albumen glands with ecdysteroid stimulated polysaccharide synthesis. The results are discussed in relation to the possible function(s) of ecdysteroids in pulmonate snails. 相似文献
224.
225.
Malhat Hend A. Zainud-Deen Saber H. Shabayek Nagwa A. 《Plasmonics (Norwell, Mass.)》2020,15(4):1025-1033
Plasmonics - Military applications employ metallic objects with different shapes, which must produce low radar cross-section (RCS) to avoid detection and destruction from explosive devices. A... 相似文献
226.
227.
Zainud-Deen Saber H. Malhat Hend A. El-Refaay Esraa A. 《Plasmonics (Norwell, Mass.)》2020,15(4):1115-1122
Plasmonics - A polarization-independent gas sensor based on crescent plasmonic dipole antenna loaded with graphene monolayer is introduced in this paper for environment... 相似文献