全文获取类型
收费全文 | 1354篇 |
免费 | 164篇 |
国内免费 | 1篇 |
出版年
2020年 | 8篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 23篇 |
2015年 | 25篇 |
2014年 | 26篇 |
2013年 | 91篇 |
2012年 | 56篇 |
2011年 | 76篇 |
2010年 | 42篇 |
2009年 | 31篇 |
2008年 | 58篇 |
2007年 | 56篇 |
2006年 | 56篇 |
2005年 | 63篇 |
2004年 | 66篇 |
2003年 | 71篇 |
2002年 | 87篇 |
2001年 | 41篇 |
2000年 | 49篇 |
1999年 | 39篇 |
1998年 | 29篇 |
1997年 | 16篇 |
1996年 | 11篇 |
1995年 | 10篇 |
1994年 | 20篇 |
1993年 | 20篇 |
1992年 | 41篇 |
1991年 | 27篇 |
1990年 | 37篇 |
1989年 | 30篇 |
1988年 | 34篇 |
1987年 | 24篇 |
1986年 | 22篇 |
1985年 | 17篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 14篇 |
1980年 | 8篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 13篇 |
1975年 | 11篇 |
1974年 | 13篇 |
1973年 | 7篇 |
1971年 | 9篇 |
1970年 | 10篇 |
1969年 | 7篇 |
1968年 | 13篇 |
1966年 | 7篇 |
排序方式: 共有1519条查询结果,搜索用时 218 毫秒
1.
2.
O Hatase A Doi T Itano H Matsui Y Ohmura 《Biochemical and biophysical research communications》1985,132(1):63-66
The presence and localization of mitochondrial calmodulin was directly proved immuno-electron microscopically by the protein A-gold technique. In the ultra-pure mitochondria the complexes of anti-calmodulin antibody and protein A-gold clearly showed the localization of mitochondrial calmodulin on the inner membrane and in the matrix space. 相似文献
3.
Kenji Doi Akemi Doi Takeshi Ozaki Toshio Fukui 《Bioscience, biotechnology, and biochemistry》2013,77(7):1629-1633
The action pattern of lytic β-1,3 glucanase (glucanase I) from Arthrobacter which liberates predominantly laminaripentaose from various β-glucans has been studied. The enzyme was not active on short linear laminaridextrins, but was active on an enzymatically synthesized, linear β-1,3 oligoglucan preparation. Any intactness of the glucose residues of the chain ends of a substrate did not seem to be necessary for the action of the enzyme. The results of determination of laminaripentaose during a relatively early phase of the reaction suggested that about half of the reducing power liberated in the medium might be explained by the formation of the sugar. It seems that the formation of laminaripentaose relates to the initial attack of glucanase 1 on β-1,3 glucan chains. 相似文献
4.
5.
6.
7.
Hideyuki Doi Elena I. Zuykova Eisuke Kikuchi Shuichi Shikano Keiichi Kanou Natalia Yurlova Elena Yadrenkina 《Hydrobiologia》2006,571(1):395-400
We investigated spatial changes in the isotope ratios of the plankton food web in Lake Chany, Siberia, Russia, especially
at an estuarine transition zone of the lake. The δ13C values of particulate organic matter (POM) varied among the sampling sites, and increased with increasing pH of the lake
water. This may reflect a shift by phytoplankton from using CO2 to using bicarbonate for photosynthesis with increasing pH. The δ13C values of zooplankton community also changed at each site along with those of the POM. This was indicative of carbon isotope
changes of plankton food webs between the stations along an environmental gradient. 相似文献
8.
The spawning site of the fluvial eight-barbel loach, Lefua sp. (sensu Hosoya, 1993; Japanese name: nagare-hotoke-dojo), an endangered species, was investigated by searching for fertilized
eggs in June and July 1995–1997 in an upper reach of the Kako River, Hyogo Prefecture, Japan. We obtained one egg each by
a random sampling with agitating the river bottom (80 trials) and by collecting drift samples (89 trials). This finding indicates
that the eggs were not scattered on the bottom or into the water column after being spawned. Two individual males were observed
to patrol around particular interstices occurring under the buried cobbles and under the boulders that formed the riverbank.
Males pecked other individuals that approached around the interstices. We obtained 9 and 15 eggs, respectively, from two such
interstices in only two collection trials. The interstices were suggested to function as the spawning sites of this endangered
fish in nature. 相似文献
9.
Masako Nomaguchi Masaru Yokoyama Ken Kono Emi E. Nakayama Tatsuo Shioda Naoya Doi Sachi Fujiwara Akatsuki Saito Hirofumi Akari Kei Miyakawa Akihide Ryo Hirotaka Ode Yasumasa Iwatani Tomoyuki Miura Tatsuhiko Igarashi Hironori Sato Akio Adachi 《Journal of virology》2013,87(21):11447-11461
Human immunodeficiency virus type 1 (HIV-1) replication in macaque cells is restricted mainly by antiviral cellular APOBEC3, TRIM5α/TRIM5CypA, and tetherin proteins. For basic and clinical HIV-1/AIDS studies, efforts to construct macaque-tropic HIV-1 (HIV-1mt) have been made by us and others. Although rhesus macaques are commonly and successfully used as infection models, no HIV-1 derivatives suitable for in vivo rhesus research are available to date. In this study, to obtain novel HIV-1mt clones that are resistant to major restriction factors, we altered Gag and Vpu of our best HIV-1mt clone described previously. First, by sequence- and structure-guided mutagenesis, three amino acid residues in Gag-capsid (CA) (M94L/R98S/G114Q) were found to be responsible for viral growth enhancement in a macaque cell line. Results of in vitro TRIM5α susceptibility testing of HIV-1mt carrying these substitutions correlated well with the increased viral replication potential in macaque peripheral blood mononuclear cells (PBMCs) with different TRIM5 alleles, suggesting that the three amino acids in HIV-1mt CA are involved in the interaction with TRIM5α. Second, we replaced the transmembrane domain of Vpu of this clone with the corresponding region of simian immunodeficiency virus SIVgsn166 Vpu. The resultant clone, MN4/LSDQgtu, was able to antagonize macaque but not human tetherin, and its Vpu effectively functioned during viral replication in a macaque cell line. Notably, MN4/LSDQgtu grew comparably to SIVmac239 and much better than any of our other HIV-1mt clones in rhesus macaque PBMCs. In sum, MN4/LSDQgtu is the first HIV-1 derivative that exhibits resistance to the major restriction factors in rhesus macaque cells. 相似文献
10.
Two kinds of carboxypeptidases (F–I, F–II) were purified from the sarcocarp of watermelon (Citrullus vulgaris, var. Shimao). F–I was not purified to homogeneity. F–II was homogeneous on ultracentrifugal analysis, but a trace of impurity was detected at high concentrations by disc electrophoresis.F–I was optimally active and stable at pH 5.0~5.5 and was strongly inhibited by DFP and HgCl2, but not by EDTA. The molecular weight and isoelectric point were 89,000 and 4.4, respectively.F–II was optimally active at pH 5.0 ~ 5.5 and was most stable at pH 5.5 ~ 7.0. It was completely inhibited by DFP and HgCl2, but not by EDTA and 1, 10-phenanthroline, and it hydrolyzed an oligopeptide containing proline, glutamic acid, lysine and several neutral amino acids, sequentially from the C-terminal. The molecular weight and isolelectric point were 110,000 (5.1 S) and 5.0, respectively.The similarity of enzymatic properties of both the present enzymes to those of other plant carboxypeptidases and pig kidney cathepsin A are discussed. 相似文献