全文获取类型
收费全文 | 831篇 |
免费 | 41篇 |
出版年
2022年 | 9篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 30篇 |
2014年 | 27篇 |
2013年 | 133篇 |
2012年 | 59篇 |
2011年 | 45篇 |
2010年 | 36篇 |
2009年 | 24篇 |
2008年 | 46篇 |
2007年 | 47篇 |
2006年 | 63篇 |
2005年 | 29篇 |
2004年 | 42篇 |
2003年 | 30篇 |
2002年 | 34篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有872条查询结果,搜索用时 31 毫秒
861.
S Togashi R Ueda M Takahisa M Mikuni K Kondo T Miyake 《The Japanese Journal of Genetics》1992,67(4):291-297
Drosophila yakuba, a member of melanogaster subgroup being free of P element, acquired resistance to an antibiotic neomycin by the transformation utilizing P element. In this species, the transformation frequency was comparable to that of D. melanogaster. Further, the occurrence of 8 base pairs duplication upon the insertion of the element was confirmed. These facts suggest that the P element could be inserted into the genome in the same manner, even in D. yakuba. Any consensus for preferential insertion could not be found on the nucleotide sequence as in D. melanogaster. However, it is noticeable that a series of the short palindromic stretches was common around the insertion sites in both species. It suggests that a structural feature of DNA plays a role as a landmark for P element insertion. 相似文献
862.
The nucleotide sequence of a proline tRNA from Bacillus subtilis W168 was determined to be pC-G-G-G-A-A-G-U-A-G-C-U-C-A-G- C-U-U-G-G-D-A-G-A-G-C-A-C-A-U-G-G-psi-U-mo5U-G-G-m1G-A-C-C-A-U-G-G -G-m7G-U-C-G-C-A-G-G-T-psi-C-G-A-A-U-C-C-U-G-U-C-U-U-C-C-C-G-A-C-C- AOH, by the analysis of the unlabeled preparation and by post-labeling technique. This tRNAPro contained 5-methoxyuridine (mo5U) which is specifically distributed in bacillaceae at the wobble position of the anticodon. 相似文献
863.
Son Hoang Minh Duc Hoang Minh Masuda Yoshimitsu Honjoh Ken-ichi Miyamoto Takahisa 《Applied microbiology and biotechnology》2018,102(23):10259-10271
Applied Microbiology and Biotechnology - Shiga toxin-producing Escherichia coli (STEC) O157:H7 and extended-spectrum beta-lactamase (ESBL) producing E. coli (ESBLEC) are important bacteria of... 相似文献
864.
Variation in the level of polyandry of females produces a difference in the risk of sperm competition among males. As a consequence,
investment in ejaculate expenditure by males should vary. We compared the number of sperm ejaculated by males into the female
reproductive organ of six strains of the adzuki bean beetle, Callosobruchus chinensis (Coleoptera: Bruchidae), when males were reared at different larval densities in a bean. A significant positive correlation
was found between the remating frequency of females and the ratio of the ejaculate sizes of high-density and low-density males
as a measure of the response to the risk of sperm competition among males. The measure was estimated by dividing the number
of sperm ejaculated by males reared at high larval density in a bean with the number of sperm ejaculated by males reared alone.
The number of sperm transferred by a male to a female was not correlated with the duration of copulation. The results suggest
an evolutionary relationship between ejaculatory expenditure and the level of polyandry in C. chinensis. 相似文献
865.
866.
A quantitative genetic analysis of rapid evolution of a life history trait has been conducted on the first 24 generations
of mass-rearing in the melon fly Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae). The phenotypic variance of larval development time in each generation was divided into
genetic and residual components. Mean and phenotypic coefficients of variation of larval development time decreased gradually
as generations proceeded as a result of artificial selection for shorter larval period in the mass-rearing procedure. There
was a trend that additive genetic coefficients of variation in larval development time decreased with generations. These changes
are entirely attributed to genetic responses to laboratory selection under the mass-rearing environment because the population
was maintained at a very large size so as to exclude random genetic drift and inbreeding depression, which would be other
factors responsible for the observed genetic changes. The residual coefficients of variation in larval development time did
not change with generations. Realized heritability of larval development time was low. The heritabilities for larval development
time estimated from parent–offspring regression at generations 60 and 70, when the evolutionary plateau was asymptotically
reached, were not significantly larger than 0.
Received: April 22, 1999 / Accepted: September 20, 1999 相似文献
867.
Toshio Joh Tsuguhiko Yoshida Makoto Yoshimoto Takahisa Miyamoto Shoji Hatano 《Physiologia plantarum》1993,89(2):285-290
The composition and positional distribution of fatty acids in the polar lipids from 4 strains of Chlorella differing in chilling susceptibility and frost hardiness were analyzed by enzymatic hydrolysis and gas-liquid chromatography. Analysis of the polar lipids from chilling-sensitive, chilling-resistant and chilling-sensitive revertant strains of Chlorella ellipsoidea IAM C-102 showed that the sum of palmitic and trans -3-hexadecenoic acid in phosphatidylglycerol (PG) is about 60% for the sensitive strains and 53% for the resistant strain. The sum of dipalmitoyl and 1-palmitoyl-2-( trans -3-hexadecenoyl) PG as estimated from the positional distribution of their fatty acids, is about 10% in the case of each of the three strains. The contents of unsaturated fatty acids in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were higher in the resistant than in the sensitive strain. This suggests that unsaturation of fatty acids in not only PG but also PC and PE is involved in chilling sensitivity of Chlorella . On the other hand, lipid changes during the development of frost hardiness of C. ellipsoidea IAM C-27, a frost hardy strain, were examined. The results showed that fatty acids in most lipid classes are unsaturated in the hardening process but their degree of unsaturation is not greatly different from that of the chilling-resistant strain, suggesting that not only unsaturation of fatty acids in lipids but also other factors are necessary for the development of frost hardiness. 相似文献
868.
Kentarou Matsumura Ryohei Ito Takahisa Miyatake 《Ethology : formerly Zeitschrift fur Tierpsychologie》2019,125(3):127-132
The pace‐of‐life syndrome (POLS) hypothesis means that animal behavior is correlated with life history strategies. Studies have reported that the free‐running period of the circadian rhythm (length of the period) is correlated with life history strategies in some animals. Although the length of the circadian rhythm may be associated with the POLS hypothesis, few studies have investigated the relationships among animal behavior, life history traits, and circadian rhythm. We tested the POLS hypothesis in the assassin bug, Amphibolus venator, which shows individual variation in locomotor activity. We found higher repeatability of differences in locomotor activity between individuals. Moreover, we found a trade‐off between locomotor activity and developmental period such that active individuals developed faster. However, locomotor activity was not correlated with the length of the circadian rhythm in A. venator. Therefore, this study suggests that the length of the circadian rhythm in A. venator does not support the POLS hypothesis. 相似文献
869.
Synthesis of deoxynucleoside-5'-tri-3'-diphosphates by Streptomyces adephospholyticus ATP:nucleotide pyrophosphokinase 总被引:1,自引:0,他引:1
ATP: nucleotide pyrophosphokinase (EC 2.7.6.4.) of Streptomyces adephospholyticus catalyzes an efficient transfer of the 5′-β,γ-pyrophosphoryl group of dATP to the four common deoxynucleoside-5′-triphosphates at their 3′-OH positions in the alkaline pH and in the presence of Co2+ ions, giving the respective 3′-pyrophosphoryl derivatives. Deoxyadenosine-5′-tri-3′-diphosphate was chromatographically prepared and structurally characterized. 相似文献
870.
Takahisa Kouwaki Toru Okamoto Ayano Ito Yukari Sugiyama Kazuo Yamashita Tatsuya Suzuki Shinji Kusakabe Junki Hirano Takasuke Fukuhara Atsuya Yamashita Kazunobu Saito Daisuke Okuzaki Koichi Watashi Masaya Sugiyama Sachiyo Yoshio Daron M. Standley Tatsuya Kanto Masashi Mizokami Kohji Moriishi Yoshiharu Matsuura 《Journal of virology》2016,90(7):3530-3542