全文获取类型
收费全文 | 939篇 |
免费 | 34篇 |
专业分类
973篇 |
出版年
2021年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 29篇 |
2013年 | 96篇 |
2012年 | 49篇 |
2011年 | 59篇 |
2010年 | 22篇 |
2009年 | 28篇 |
2008年 | 62篇 |
2007年 | 48篇 |
2006年 | 51篇 |
2005年 | 48篇 |
2004年 | 60篇 |
2003年 | 60篇 |
2002年 | 49篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 13篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 13篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 8篇 |
1972年 | 3篇 |
1970年 | 5篇 |
排序方式: 共有973条查询结果,搜索用时 15 毫秒
941.
Teruo Tanaka 《Molecular & general genetics : MGG》1979,175(2):235-237
Summary When plasmids carrying leucine genes of Bacillus subtilis 168 were isolated from a restriction and modification deficient (r-m-) strain and used for transformation of a restricting strain B. subtilis 168 leu recE4, the number of transformants was greatly reduced. Transformation of a rec
+ strain (transformation by integration of the donor DNA into the chromosome) with the plasmids was not affected irrespective of whether the recipient carried the r+ or r- phenotype. These results show that the plasmid-mediated transformation is subject to the host controlled restriction and suggest that r-m- strains should be used for construction of recombinant DNA molecules in B. subtilis 168. 相似文献
942.
Tetsuo Meshi Masayuki Ishikawa Yoshinori Watanabe Jun Yamaya Yoshimi Okada Teruo Sano Eishiro Shikata 《Molecular & general genetics : MGG》1985,200(2):199-206
Summary Recombinant plasmids carrying more than two units of the hop stunt viroid (HSV) cDNA sequence linked in tandem were highly infectious. On the other hand, those carrying one unit were not. To determine the length of the HSV cDNA sequence necessary for the infectivity, we constructed series of plasmids carrying more than one but less than two units of the HSV sequence and investigated their infectivities. The results showed that cDNA clones were infectious if about 60 nucleotides of the internal part of the HSV sequence (region A) were undeleted and remained with the same arrangement as in the infectious two-unit clone. The region A can be folded into a stable secondary structure. Viroid replication is thought to involve a site-specific endonucleolytic cleavage of plus strand RNA multimers produced by a rolling circle mechanism to yield unit length molecules. Our results suggest that the region A contains the sequence or structure recognized by the putative endonuclease. 相似文献
943.
Two processes of the K+ channel activation in plasma membraneexcitation are suggested for Nitella axilliformis. One is relatedto the repolarizing process in the action potential and theother to the after-hyperpolarization (AH). Extra- and intracellulartetraethylammonium (TEA+) and extracellular Co2+ prolonged theaction potential, indicating involvement of K+ channel activationin the repolarizing process of the action potential. The following findings showed that AH is caused by K+ channelactivation. First, AH was inhibited by extracellular K+ andRb+ but not by Na+ and Li+. Second, it was not inhibited byintracellular TEA+ but by extracellular TEA+. Third, the membraneconductance increased during AH. Generation of AH was dependenton the level of the resting membrane potential [(Em)rest] whichis affected by the activity of the electrogenic H+ pump. AHwas generated, when (Em)rest was more positive than a criticalvalue, which was supposed to be the equilibrium potential forK+ across the plasma membrane. Since extracellular Ca2+ competed with extracellular TEA+ andCo2+ in prolonging the action potential, and sometimes in inhibitingAH, Ca2+ may be involved in the K+ channel activation. (Received June 11, 1983; Accepted September 21, 1983) 相似文献
944.
945.
The activities of laccase and tyrosinase, that is, oxidation activities ofp-phenylenediamine andp-cresol in the fruiting bodies of species belonging to various genera of Agaricales were examined. Among 40 genera examined,
appreciable laccase activities were observed in fungi belonging toLepista, Omphalina, Agaricus, Russula andLactarius. High typosinase activities were found in many species ofHygrophorus, Laccaria, Lepista, Melanoleuca, Collybia, Marasmius, Amanita, Agaricus, Inocybe, Pholiota, Russula andLactarius. Species of other genera exmained did not show either enzyme activities to any extent.
FromRussula delica andRussula pseudodelica, laccases were extracted and purified, and some characteristics were compared. Molecular weight and absorption spectra of
these laccases were very similar to each other, but they were different in electrophoretical mobilities and substrate specificity.
This work was presented at the Annual Meeting of the Bot. Soc Japan in Oct. 1970 at Matsuyama. 相似文献
946.
947.
Naoto Inoue Teruo Arase Motoyuki Hagiwara Takahisa Amano Taiichi Hayashi Ryoichi Ikeda 《Ecological Research》1999,14(1):31-38
How plant seeds secure root penetration into soil to obtain good seedling establishment is one of the basic ecological problems. In this study, seminal root growth was investigated to clarify the cause of varietal difference of seedling establishment in direct seeding of rice in flooded paddy fields, with special reference to root tip rotation. In a field experiment, seedling establishment percentage had a weak correlation with seminal root elongation rate but was not correlated with apparent seedling weight in water, which has been reported to be the cause of floating seedlings resulting in poor seedling establishment. Root tip rotation was analyzed for indoor-grown seedlings using spectrum analysis: the maximum entropy method (MEM) was used. Maximum entropy method power spectrum analysis clarified that maximum MEM power density (practically corresponds to spiral angle) detected in the frequency range above 0.1 cycles mm-1 was highly and positively correlated to seedling establishment percentage in the field experiment. Maximum MEM power density in high correlation with seedling establishment was mostly found around frequencies of 0.2 cycles mm–1, which corresponded to 2.0–3.4 cycles of root tip rotation per day. From these results, root tip rotation (circumnutation) with a larger spiral angle was suggested to play an important role in the establishment of rice seedlings on flooded and very soft soil. A possible explanation for why a larger spiral angle was advantageous for seedling establishment is that if buoyancy and seedling weight are constant, a larger pushing force of the seminal root is available without causing floating of a seedling, due to the upward force being a reaction of the seminal root pushing force. 相似文献
948.
Although the binding of synaphin (also called complexin) to the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex is critical for synaptic vesicle exocytosis, the exact role of synaphin remains unclear. Here, we show that synaphin directly binds to synaptotagmin 1, a major Ca2+ sensor for fast neurotransmitter release, in a 1:1 stoichiometry. Mapping of the synaphin site involved in synaptotagmin 1 binding revealed that the C-terminal region is essential for the interaction between these two proteins. Binding was sensitive to ionic strength, suggesting the involvement of charged residues in the C-terminus region. Mutation of the seven consecutive glutamic acid residues (residues 108–114) at the C-terminal region of synaphin to alanines or glutamines resulted in a dramatic reduction in synaptotagmin 1 binding activity. Furthermore, a peptide from the C-terminus of synaphin (residues 91–124) blocked the binding of synaptotagmin 1 to synaphin, an effect that was abolished by mutating the consecutive glutamic acid residues to alanine. Immunoprecipitation experiments with brain membrane extracts showed the presence of a complex consisting of synaphin, synaptotagmin 1, and SNAREs. We propose that synaphin recruits synaptotagmin 1 to the SNARE-based fusion complex and synergistically functions with synaptotagmin 1 in mediating fast synaptic vesicle exocytosis. 相似文献
949.
Sensitive aequorin was microinjected into the cytoplasm of Nitellaflexilis to study the role of Ca2+ in the generation of thetonoplast action potential. The temporal relation between theincrease in cytoplasmic Ca2+ and the tonoplast action potentialsuggested that tonoplast action potential is triggered by anincrease in cytoplasmic Ca2+. This is also supported by thefact that Mn2+, extracellularly applied, inhibited both theincrease in cytoplasmic Ca2+ and the generation of the tonoplastaction potential. (Received April 2, 1997; Accepted June 7, 1997) 相似文献