全文获取类型
收费全文 | 95篇 |
免费 | 26篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 2篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1978年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 15 毫秒
21.
Preparation of Encapsulated Microbial Cells for Environmental Applications 总被引:3,自引:1,他引:2
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
An improved method for the encapsulation of bacteria into microspheres of alginate, agarose, or polyurethane is described. Cell suspensions were passed through a low-pressure nozzle into an aqueous phase where matrix polymerization or gelation yielded beads 2 to 50 μm in diameter. Trials with a chlorophenol-degrading Flavobacterium species showed that cells entrapped by these procedures were as catabolically active as free cells. These types of beads should have numerous applications in the fields of environmental science and engineering. 相似文献
22.
Detection of deletions in the mitochondrial genome of Caenorhabditis elegans. 总被引:2,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We have examined an aging population of Caenorhabditis elegans via a PCR assay to determine if deletions in the mitochondrial genome occur in the nematode. We detected eight such deletions, identified the breakpoints of four of these, and discovered direct repeats of 4-8 base pairs at the site of all four deletions. Six of the eight repeats involved in the deletions are located in or immediately adjacent to tRNAs. Without a biochemical bias, the probability of direct repeats being present at all four breakpoints was 4 x 10(-6). 相似文献
23.
24.
25.
26.
Olfactory contribution to Fos expression during mating in inexperienced male hamsters 总被引:1,自引:0,他引:1
Male hamsters are very dependent on chemosensory cues for normal mating
behavior. We have previously reported that central, vomeronasal pathways
are intensely and selectively activated during mating or pheromonal
stimulation. The contribution of main olfactory sensory input to the
patterns of c-fos activation was investigated in this study. Sexually
inexperienced male hamsters were either made anosmic by intranasal infusion
of zinc sulfate or remained intact. Fos protein immunoreactivity was
analyzed in main olfactory and vomeronasal pathways of the zinc
sulfate-treated, anosmic animals after mating with receptive females for 45
min, and compared with Fos patterns seen in intact mating animals, some of
which have been described in a previous publication. The zinc
sulfate-treated anosmic males described here all mated when given access to
receptive females. Whether mated or unstimulated, anosmic males had little
or no Fos expression in main olfactory pathways; significantly less even
than in unstimulated intact animals. Mating did not increase Fos expression
in main olfactory pathways of intact animals over that of unstimulated
intact controls. However, Fos expression in central vomeronasal pathways
was significantly higher in mating anosmic males, as in intact males,
compared with appropriate non-mating controls. Fos expression was
significantly different between intact and zinc sulfate-treated anosmic
mating males in only one area studied. The rostral anterior medial
amygdala, known to receive a small olfactory terminal field, had
significantly lower Fos expression in zinc sulfate-treated anosmic males
that mated when compared with intact-mating animals. Thus, functional main
olfactory input to the rostral vomeronasal amygdala can be demonstrated but
does not appear to be critical for mating behavior in previously
inexperienced male hamsters with intact vomeronasal organs. Other main
olfactory input appears to have a negligible contribution to Fos-patterns
in such animals.
相似文献
27.
Zhong-Cheng Hu Roger A. Korus Keith E. Stormo 《Applied microbiology and biotechnology》1993,39(3):289-295
-d-Galactosidase (E 3.2.1.23) from Aspergillus oryzae was immobilized with polyurethane foam (PUF). Among several immobilization methods attempted in this work, the immobilized enzyme preparation by in-situ co-polymerization between enzyme and prepolymer HYPOL 3000 showed the highest activity. The intrinsic kinetics of PUF-immobilized enzyme was determined in a dynamic bed reactor, used to increase transport rates. The immobilization mechanism in PUF was studied by measurements of immobilized enzyme kinetics and by using scanning electron microscopy combined with immuno-gold labeling techniques. The results showed that immobilization was predominantly by covalent bonding between primary amino groups of -d-galactosidase and isocyanate groups of the prepolymers. Entrapment in the PUF micropores assisted the immobilization of enzymes, and adsorption on the surface of macropores was not important for immobilization. The bicinchoninic acid method was applied for the determination of PUF loading capacity and specific enzyme activity and used to determine enzyme deactivation during immobilization. 相似文献
28.
Intermediate filaments in nervous tissues 总被引:59,自引:30,他引:29
Intermediate filaments have been isolated from rabbit intradural spinal nerve roots by the axonal flotation method. This method was modified to avoid exposure of axons to low ionic strength medium. The purified filaments are morphologically 75-80 percent pure. The gel electrophoretogram shows four major bands migrating at 200,000, 145,000, 68,000, and 60,000 daltons, respectively. A similar preparation from rabbit brain shows four major polypeptides with mol wt of 200,000 145,000, 68,000, and 51,000 daltons. These results indicate that the neurofilament is composed of a triplet of polypepetides with mol wt of 200,000, 145,000, and 68,000 daltons. The 51,000-dalton band that appears in brain filament preparations as the major polypeptide seems to be of glial origin. The significance of the 60,000- dalton band in the nerve root filament preparation is unclear at this time. Antibodies raised against two of the triplet proteins isolated from calf brain localize by immunofluorescence to neurons in central and peripheral nerve. On the other hand, an antibody to the 51,000-dalton polypeptide gives only glial staining in the brain, and very weak peripheral nerve staining. Prolonged exposure of axons to low ionic strength medium solubilizes almost all of the triplet polypeptides, leaving behind only the 51,000- dalton component. This would indicate that the neurofilament is soluble at low ionic strength, whereas the glial filament is not. These results indicate that neurofilaments and glial filaments are composed of different polypeptides and have different solubility characteristics. 相似文献
29.
Sequence requirements of the hammerhead RNA self-cleavage reaction. 总被引:51,自引:0,他引:51
A previously well-characterized hammerhead catalytic RNA consisting of a 24-nucleotide substrate and a 19-nucleotide ribozyme was used to perform an extensive mutagenesis study. The cleavage rates of 21 different substrate mutations and 24 different ribozyme mutations were determined. Only one of the three phylogenetically conserved base pairs but all nine of the conserved single-stranded residues in the central core are needed for self cleavage. In most cases the mutations did not alter the ability of the hammerhead to assemble into a bimolecular complex. In the few cases where mutant hammerheads did not assemble, it appeared to be the result of the mutation stabilizing an alternate substrate or ribozyme secondary structure. All combinations of mutant substrate and mutant ribozyme were less active than the corresponding single mutations, suggesting that the hammerhead contains few, if any, replaceable tertiary interactions as are found in tRNA. The refined consensus hammerhead resulting from this work was used to identify potential hammerheads present in a variety of Escherichia coli gene sequences. 相似文献
30.
A design for computer nucleic-acid-sequence storage, retrieval, and manipulation 总被引:10,自引:7,他引:3
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Thomas D. Schneider Gary D. Stormo Jeffrey S. Haemer Larry Gold 《Nucleic acids research》1982,10(9):3013-3024
We have designed and built a data-base system for the storage of nucleic-acid sequences. The system consists of a data base (“the library”) and software that manages and provides access to that data base (“the Librarian”). 相似文献