全文获取类型
收费全文 | 381篇 |
免费 | 6篇 |
国内免费 | 4篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 14篇 |
2012年 | 15篇 |
2011年 | 14篇 |
2010年 | 17篇 |
2009年 | 18篇 |
2008年 | 12篇 |
2007年 | 22篇 |
2006年 | 18篇 |
2005年 | 20篇 |
2004年 | 15篇 |
2003年 | 4篇 |
2002年 | 18篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1981年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有391条查询结果,搜索用时 15 毫秒
1.
S. P. Kharitonov D. E. Nowak A. I. Nowak N. A. Egorova S. A. Korkina D. V. Osipov O. V. Natal’skaya 《Biology Bulletin》2009,36(5):469-478
Red-breasted goose colonies have been studied near Medusa Bay (73°21′N, 80°32′E), on the northwestern Taimyr Peninsula, and
along the Agapa River (70°11′N, 86°15′E) down to its mouth (71°26′N, 89° 13′E), in the central Taimyr Peninsula. Red-breasted
geese nesting near peregrine falcons are protected by the falcons from arctic foxes; however, they are sometimes attacked
by the falcons themselves. In the colonies near peregrine falcon nests, the vast majority of goose nests were situated no
farther than 100 m from the falcon nest. When food is abundant, falcons protect a larger area around their nest. The distance
between the falcon nest and the surrounding goose nests is inversely related to the falcon’s activity. In years of higher
falcon activity, falcons prevent red-breasted geese from nesting as close to their nest as in years of lower falcon activity.
Additional stimuli are required for red-breasted geese to form colonies near rough-legged buzzard nests. The distance between
snowy owl nests and red-breasted goose nests was smaller when arctic foxes were abundant than when they were scarce. 相似文献
2.
E D Bershadskaia N G Fish P P Shev'ev M A Osipov V I Ogarkov 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1986,(9):32-35
Anabol and blastolysin preparations obtained from L. bulgaricus may contain surface structural components of the initial strain with adhesion activity; of these, one is similar in specificity to L. casei adhesin and the other, to L. plantarum adhesin. The antigenic activity of anabol and blastolysin, evaluated in the immunodiffusion test, does not correlate with their capacity for binding the receptors of susceptible bacterial cells, determined in the Lactobacillus-induced hemagglutination inhibition test. 相似文献
3.
As it is previously shown (Tsyrlova et al., 1986), the level of humoral immune response is not only determined by the reaction of peripheral lymphoid system on antigenic effect, but also is bound up with the observed stem blood cell (SBC) proliferation in bone marrow (Frindel et al., 1976, Kozlov et al., 1982). Dynamics of label accumulation in bone marrow was examined when injecting antigen--sheep red blood cells labeled by radioisotope 51Cr, 125I. The peak of label accumulation in bone marrow, accompanied by the increase in proliferative SBC, was observed on the 3rd day after antigen injection. Furthermore in the course of immunization 51Cr labeled macrophage assortment was changed in time in such a way that a greater number of macrophages was accumulated in bone marrow on the 3rd and 4th days in the immunized animals in comparison with the intact ones. The macrophages in bone marrow are likely to take part in antigen uptake and to mediate its effect on SBC proliferation. 相似文献
4.
Nielsen J; Peixoto AA; Piccin A; Costa R; Kyriacou CP; Chalmers D 《Molecular biology and evolution》1994,11(6):839-853
The region of the clock gene period (per) that encodes a repetitive tract
of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran
species both within and outside the Drosophilidae. All the non-
Drosophilidae sequences in this region are short and present a remarkably
stable picture compared to the Drosophilidae, in which the region is much
larger and extremely variable, both in size and composition. The
accelerated evolution in the repetitive region of the Drosophilidae appears
to be mainly due to an expansion of two ancestral repeats, one encoding a
Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and
asparagine or threonine. In some drosophilids the expansion involves a
duplication of the pentapeptide sequence, but in Drosophila pseudoobscura
both the dipeptide and the pentapeptide repeats are present in larger
numbers. In the nondrosophilids, however, the pentapeptide sequence is
represented by one copy and the dipeptide by two copies. These observations
fulfill some of the predictions of recent theoretical models that have
simulated the evolution of repetitive sequences.
相似文献
5.
Evolutionary origin of human and primate malarias: evidence from the circumsporozoite protein gene 总被引:8,自引:1,他引:7
We have analyzed the conserved regions of the gene coding for the
circumsporozoite protein (CSP) in 12 species of Plasmodium, the malaria
parasite. The closest evolutionary relative of P. falciparum, the agent of
malignant human malaria, is P. reichenowi, a chimpanzee parasite. This is
consistent with the hypothesis that P. falciparum is an ancient human
parasite, associated with humans since the divergence of the hominids from
their closest hominoid relatives. Three other human Plasmodium species are
each genetically indistinguishable from species parasitic to nonhuman
primates; that is, for the DNA sequences included in our analysis, the
differences between species are not greater than the differences between
strains of the human species. The human P. malariae is indistinguishable
from P. brasilianum, and P. vivax is indistinguishable from P. simium; P.
brasilianum and P. simium are parasitic to New World monkeys. The human P.
vivax-like is indistinguishable from P. simiovale, a parasite of Old World
macaques. We conjecture that P. malariae, P. vivax, and P. vivax-like are
evolutionarily recent human parasites, the first two at least acquired only
within the last several thousand years, and perhaps within the last few
hundred years, after the expansion of human populations in South America
following the European colonizations. We estimate the rate of evolution of
the conserved regions of the CSP gene as 2.46 x 10(-9) per site per year.
The divergence between the P. falciparum and P. reichenowi lineages is
accordingly dated 8.9 Myr ago. The divergence between the three lineages
leading to the human parasites is very ancient, about 100 Myr old between
P. malariae and P. vivax (and P. vivax-like) and about 165 Myr old between
P. falciparum and the other two.
相似文献
6.
J. Bubeník J. Ježek M. Zaoral J. Hofmann Y. V. Gruntenko J. G. Osipov A. G. Zolotareva T. E. Vakhrusheva V. G. Budker 《Cancer immunology, immunotherapy : CII》1984,18(2):123-125
Summary Treatment with synthetic MDP inhibited growth of transplantable, chemically induced tumors in syngeneic mice. The tumor-inhibitory effect was dependent on the schedule of MDP administration.Growth of SC transplants of a nonmetastasizing, MC-induced fibrosarcoma, MC11, was inhibited by local treatment with 200 g and 1,000 g MDP given SC 5–7 weeks before challenge. Treatment with lower (10 g and 100 g) doses of MDP and shorter (1–4 weeks) time intervals was not effective. Single doses of MDP (10–1,000 g) 1–3 weeks after challenge had no effect.Growth of IV-inoculated, metastasizing AAT-induced hepatoma A was inhibited by IV injections of 20 g MDP given 1 and 2 days prior to the challenge. Significant increases in the survival of hepatoma-bearing mice were observed only after injections of MDP incorporated in multilamellar liposomes.Abbreviations MDP
n-acetylmuramyl-l-alanyl-d-isoglutamine
- B10
C57BL/10ScSnPh mice
- MC
3-methylcholanthrene
- ATT
o-amino-azotoluene
- PBS
phosphate-buffered saline 相似文献
7.
Photosynthetic enhancement studies performed at 619 nm (excitation of Systems I and II) and at 446 nm (mainly excitation of System I) revealed an 18% photosynthetic enhancement simultaneously with a 31% reduction in glycolate excretion. This observation supports the hypothesis that some glycolate may be consumed in an oxidation process associated with System I when System II is poorly excited and the supply of electrons from the water splitting process of photosynthesis is low. 相似文献
8.
Variation in the expressivity was studied of the gene for ocular retardation (or) in mice. It is shown that the gene or suppresses with a high expressivity the growth of the optic vesicle in homozygotes, this resulting in anophthalmia and microphthalmia with aphakia. In cases of low expressivity, the gene or inhibits the growth of retina anlage, this leading to microphthalmia with a cataract of the lens. Variation in the expressivity of the gene or is due to an influence of modifier genes. 相似文献
9.
10.
S A Shukoliukov E P Chizhevich V P Korchagin V V Osipov V A Tiurin 《Biokhimii?a (Moscow, Russia)》1976,41(1):75-80
Detergent-rhodopsin micells (component I) were separated from other fast and slow migrating protein components under electrophoresis of triton X-100 solubilized bovine rod outer segments (ROS). Treatment of ROS by alum caused a complete disappearance of non-rhodopsin proteins and the appearance of slow migrating band (component II). Preliminary bleaching of dark extracts did not affect the migration rate of the component I. The addition of urea to solubilizing mixture caused the increase of component I content and the diffusity components I and II bands. The rate of electrophoretic migration and the content of components I and II sharply decreased together with the appearance of fast migrating pink-brown band after the addition of 2-mercaptoethanol. The extracts from alum-treated ROS were separated into 15-20 protein bands under acrylamide gel isoelectric focusing. Such protein heterogeneity probably depended on the ability of triton X-100 to form micells with different isoelectric points during the interaction with ampholines in the electric field. These micells, having different isoelectric points, are shown to contain one and the same protein--opsin. 相似文献