全文获取类型
收费全文 | 243篇 |
免费 | 18篇 |
国内免费 | 4篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 17篇 |
2013年 | 9篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 9篇 |
2005年 | 12篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1995年 | 3篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 6篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 4篇 |
1967年 | 2篇 |
1966年 | 4篇 |
排序方式: 共有265条查询结果,搜索用时 46 毫秒
161.
E. S. Lobakova I. O. Selyakh L. R. Semenova O. B. Chivkunova P. N. Shcherbakov A. E. Solovchenko 《Moscow University Biological Sciences Bulletin》2016,71(2):102-107
The growth and biomass accumulation of three microalgal strains of Desmodesmus (Scenedesmaceae, Chlorophyceae), 1Рm66В, 2Cl66E, and 3Dp86Е-1, isolated from the White Sea benthic invertebrates were studied under conditions of batch culture in different standard media (BG-11, Prat, Goldberg, Gromov, Tamiya, artificial seawater) and modified media. The culture condition, biomass accumulation, and uptake of nitrate and phosphate were recorded. A significant alkalization of the culture medium up to pH 10 has been observed during a vigorous growth of the microalgae. The most significant biomass accumulation has been recorded in BG-11 (in complete or modified medium with addition of artificial seawater), Tamiya, and Prat media. Addition of seawater did not affect the growth of Desmodesmus sp. in the nitrate-containing media, although that maintained growth of the microalgae in the nitrogen-lacking media without cell aggregation. The BG-11 medium appears suitable for isolation and cultivation of both symbiotic and free-living microalgae by all the tested features. The Prat medium is the best for maintaining the microalgal strains in living collection. 相似文献
162.
NaCl-preferring NZB/B1NJ mice and NaCl-avoiding CBA/J mice have similar amiloride inhibition of chorda tympani responses to NaCl 总被引:1,自引:1,他引:0
Integrated chorda tympani nerve responses to NaCl were studied in two mouse
strains, an NaCl-preferring NZB/B1NJ and an NaCl-avoiding CBA/J. The NaCl
responses of both strains had similar magnitude and were suppressed by
amiloride to a similar extent. This suggests that peripheral gustatory
responsiveness to NaCl is not the only mechanism underlying mouse strain
variation in NaCl acceptance.
相似文献
163.
Analysis of the chlorophyll biosynthetic system in a chlorophyll b-less barley mutant 总被引:1,自引:0,他引:1
The chlorophyll b-less barley (Hordeum vulgare L.) mutant chlorina 2807 allelic to the well-known barley mutant chlorina f2 was studied. 5-Aminolevulinic acid at saturating concentration (40 mM) was introduced into postetiolated leaves of the mutant and its wild type, and the protochlorophyllide accumulation in the dark was measured. It was found that the activity of the enzyme system transforming 5-aminolevulinic acid into protochlorophyllide was the same in both types of plants. The activity of esterifying enzymes that catalyze attachment of phytol to chlorophyllide was analyzed by infiltration of exogenous chlorophyllides a and b into etiolated leaves. The reaction was shown to have close rates in the mutant and wild-type plants. In very early stages of greening of etiolated leaves, when the apoproteins of the light-harvesting complexes are not yet formed, appearance of chlorophyll b was clearly recorded in the wild-type plants, while in the mutant chlorina 2807 no indications of chlorophyll b were detected in any stage of greening. On the other hand, in the mutant as well as in the wild type an active reverse conversion of chlorophyll b into chlorophyll a was possible. It is concluded that (a) in the mutant chlorina 2807 the ability of the biosynthetic system to transform 5-aminolevulinic acid to chlorophyll a is fully preserved, (b) in the mutant the enzymes converting chlorophyll a into chlorophyll b are most likely absent or damaged, (c) the conversion of chlorophyll a into chlorophyll b and the reverse conversion of chlorophyll b into chlorophyll a are performed by different enzymes. 相似文献
164.
OI Klychnikov AV Drabkin OV Vasilenko YS Pavlov MS Trofimova IN Smolenskaya AA Rozenkranz AS Sobolev AV Babakov 《Biochemistry. Biokhimii?a》1998,63(9):1083-1089
Higher plant plasma membranes carry receptors of different affinity for the phytotoxin fusicoccin. Reception of fusicoccin involves proteins belonging to the highly conserved 14-3-3 family, but the complete structure of the fusicoccin receptor (FCR) is unknown. Using radiation inactivation analysis, we estimated the molecular masses of low-affinity and high-affinity FCR at 63 +/- 7 and 130 +/- 15 kD, respectively. The dose dependences of receptor inactivation indicate that microsomal specimens contain "silent" FCRs of 420 +/- 90 kD in amounts commensurate with that of the active FCRs. Both low- and high-affinity FCRs are inactivated by hydrolytic enzymes from the outer surface of the plasma membrane, and impairment of protoplast integrity causes an irreversible transition of the low-affinity binding site into the high-affinity one. A scheme is proposed for the organization of different types of FCR in the plasma membrane, implying that the membrane affinity for fusicoccin reflects the interaction between proteins in the FCR complex. 相似文献
165.
NOBORU FUJINAMI YUKITAKA SUGIMOTO ATSUYOSHI HAGIWAAA 《Development, growth & differentiation》1973,15(2):141-151
Enhancement of the erythroid maturation in Friend virus-induced leukemic cells has been examined in vitro by the treatment with dimethyl sulfoxide (DMSO). Although the cell growth was inhibited in the medium containing 2% DMSO, many cells remained viable for a week. By the 3rd day of the culture, the cells treated with DMSO became more strongly agglutinated by phytohemagglutinin than the cells incubated without DMSO. Mouse erythrocyte membrane-specific antigens were also detectable at the 4th day. At the 8th day of the culture hemoglobin synthesis was apparently demonstrated in the cells treated with DMSO, which could not be seen in the untreated cells. Maturation or differentiation along the erythroid pathway in Friend leukemic cells by DMSO is discussed on these markers. 相似文献
166.
Marker-Dependent Recombination in T4 Bacteriophage. III. Structural Prerequisites for Marker Discrimination 总被引:5,自引:4,他引:1
下载免费PDF全文
![点击此处可从《Genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Distance- as well as marker-dependence of genetic recombination of bacteriophage T4 was studied in crosses between rIIB mutants with known base sequences. The notion of a "basic recombination," which is the recombination within distances shorter than hybrid DNA length in the absence of mismatch repair and any marker effects, was substantiated. The basic recombination frequency per base pair can serve as an objective parameter (natural constant) of general recombination reflecting its intensity. Comparative studies of the recombination properties of rIIB mutants with various sequence changes in the mutated sites showed that the main factor determining the probability of mismatch repair in recombination heteroduplexes is the length of a continuous heterologous region. A run of A:T pairs immediately adjoining the mismatch appears to stimulate its repair. In the case of mismatches with DNA strands of unequal length, formed by frameshift mutations, the repair is asymmetric, the longer strand (bulge) being preferentially removed. A pathway for mismatch repair including sequential action of endonuclease VII (gp49)----3'----5' exonuclease (gp43)----DNA polymerase (gp43)----DNA ligase (gp30) was proposed. A possible identity of the recombinational mismatch repair mechanism to that operating to produce mutations via sequence conversion is discussed. 相似文献
167.
Alexander V. Tyakht Alexander I. Manolov Alexandra V. Kanygina Dmitry S. Ischenko Boris A. Kovarsky Anna S. Popenko Alexander V. Pavlenko Anna V. Elizarova Daria V. Rakitina Julia P. Baikova Valentina G. Ladygina Elena S. Kostryukova Irina Y. Karpova Tatyana A. Semashko Andrei K. Larin Tatyana V. Grigoryeva Mariya N. Sinyagina Sergei Y. Malanin Petr L. Shcherbakov Anastasiya Y. Kharitonova Igor L. Khalif Marina V. Shapina Igor V. Maev Dmitriy N. Andreev Elena A. Belousova Yulia M. Buzunova Dmitry G. Alexeev Vadim M. Govorun 《BMC genomics》2018,19(1):968
Background
Crohn’s disease is associated with gut dysbiosis. Independent studies have shown an increase in the abundance of certain bacterial species, particularly Escherichia coli with the adherent-invasive pathotype, in the gut. The role of these species in this disease needs to be elucidated.Methods
We performed a metagenomic study investigating the gut microbiota of patients with Crohn’s disease. A metagenomic reconstruction of the consensus genome content of the species was used to assess the genetic variability.Results
The abnormal shifts in the microbial community structures in Crohn’s disease were heterogeneous among the patients. The metagenomic data suggested the existence of multiple E. coli strains within individual patients. We discovered that the genetic diversity of the species was high and that only a few samples manifested similarity to the adherent-invasive varieties. The other species demonstrated genetic diversity comparable to that observed in the healthy subjects. Our results were supported by a comparison of the sequenced genomes of isolates from the same microbiota samples and a meta-analysis of published gut metagenomes.Conclusions
The genomic diversity of Crohn’s disease-associated E. coli within and among the patients paves the way towards an understanding of the microbial mechanisms underlying the onset and progression of the Crohn’s disease and the development of new strategies for the prevention and treatment of this disease.168.
The ability to simultaneously measure many long-range distances is critical to efficient and accurate determination of protein structures by solid-state NMR (SSNMR). So far, the most common distance constraints for proteins are 13C–15N distances, which are usually measured using the rotational-echo double-resonance (REDOR) technique. However, these measurements are restricted to distances of up to ~?5 Å due to the low gyromagnetic ratios of 15N and 13C. Here we present a robust 2D 13C–19F REDOR experiment to measure multiple distances to ~?10 Å. The technique targets proteins that contain a small number of recombinantly or synthetically incorporated fluorines. The 13C–19F REDOR sequence is combined with 2D 13C–13C correlation to resolve multiple distances in highly 13C-labeled proteins. We show that, at the high magnetic fields which are important for obtaining well resolved 13C spectra, the deleterious effect of the large 19F chemical shift anisotropy for REDOR is ameliorated by fast magic-angle spinning and is further taken into account in numerical simulations. We demonstrate this 2D 13C–13C resolved 13C–19F REDOR technique on 13C, 15N-labeled GB1. A 5-19F-Trp tagged GB1 sample shows the extraction of distances to a single fluorine atom, while a 3-19F-Tyr labeled GB1 sample allows us to evaluate the effects of multi-spin coupling and statistical 19F labeling on distance measurement. Finally, we apply this 2D REDOR experiment to membrane-bound influenza B M2 transmembrane peptide, and show that the distance between the proton-selective histidine residue and the gating tryptophan residue differs from the distances in the solution NMR structure of detergent-bound BM2. This 2D 13C–19F REDOR technique should facilitate SSNMR-based protein structure determination by increasing the measurable distances to the ~?10 Å range. 相似文献
169.
D N Maianski? V I Shcherbakov Iu M Mirokhanov 《Biulleten' eksperimental'no? biologii i meditsiny》1977,84(11):616-618
In male Wistar rats, weighing 140-160 g, the block of the liver mononuclear phagocyte system (MPS) was carried out by means of "carbonyl iron" (type R-100F, particle size 1-1.5 micron). It was induced 2 hours before or 3 and 18 hours after partial hepatectomy. Iron injection previously or at the early prereplicative regeneration period led to a significant delay of the hepatocyte nucleus labeling and mitotic indices peaks against the background of an overall depression of hepatocyte proliferation. The MPS block during the intensive DNA synthesis by regenerating liver hepatocytes was less effective. The facts testify to the importance of Kupffer's cells in the regulation of the reparative liver regeneration. 相似文献
170.
Merkuleva Yu. A. Shcherbakov D. N. Ilyichev A. A. 《Russian Journal of Bioorganic Chemistry》2022,48(2):256-272
Russian Journal of Bioorganic Chemistry - A viral threat can arise suddenly and quickly turn into a major epidemic or pandemic. In such a case, it is necessary to develop effective means of therapy... 相似文献