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51.
Patterns of differentiation and hybridization in North American wolflike canids, revealed by analysis of microsatellite loci 总被引:8,自引:0,他引:8
Roy MS; Geffen E; Smith D; Ostrander EA; Wayne RK 《Molecular biology and evolution》1994,11(4):553-570
Genetic divergence and gene flow among closely related populations are
difficult to measure because mutation rates of most nuclear loci are so low
that new mutations have not had sufficient time to appear and become fixed.
Microsatellite loci are repeat arrays of simple sequences that have high
mutation rates and are abundant in the eukaryotic genome. Large population
samples can be screened for variation by using the polymerase chain
reaction and polyacrylamide gel electrophoresis to separate alleles. We
analyzed 10 microsatellite loci to quantify genetic differentiation and
hybridization in three species of North American wolflike canids. We
expected to find a pattern of genetic differentiation by distance to exist
among wolflike canid populations, because of the finite dispersal distances
of individuals. Moreover, we predicted that, because wolflike canids are
highly mobile, hybrid zones may be more extensive and show substantial
changes in allele frequency, relative to nonhybridizing populations. We
demonstrate that wolves and coyotes do not show a pattern of genetic
differentiation by distance. Genetic subdivision in coyotes, as measured by
theta and Gst, is not significantly different from zero, reflecting
persistent gene flow among newly established populations. However, gray
wolves show significant subdivision that may be either due to drift in past
Ice Age refugia populations or a result of other causes. Finally, in areas
where gray wolves and coyotes hybridize, allele frequencies of gray wolves
are affected, but those of coyotes are not. Past hybridization between the
two species in the south-central United States may account for the origin
of the red wolf.
相似文献
52.
G. Z. Mikhailova E. N. Bezgina N. N. Kashirskaya N. A. Ivlicheva R. H. Ziganshin L. I. Kramarova 《Biophysics》2018,63(2):201-206
The effects of the Thr–Ser–Lys–Tyr peptide, which was shown to display neuroprotective activity in cell cultures in vitro, were studied in the model of paired Mauthner cells of goldfish. It was found that intracerebral injections provided the peptide to be applied into the zone of the right Mauthner cell under the fourth ventricle of the hindbrain lead to a dose-dependent decrease in the number of spontaneous turns of the goldfish to the left. It was shown that this effect is not eliminated under long-lasting optokinetic stimulation when the fish instinctively follow stimuli with a low spatial frequency that are moving in the nasal-to-temporal direction. We used the method of three-dimensional reconstruction by serial histological sections to study the dendrite morphology of the Mauthner cells in control and experimental goldfish. It was found that optokinetic stimulation of control goldfish evokes the dystrophy of the ventral dendrite of the right Mauthner cell, which is the target of this type of stimulation. Conversely, the peptide stabilize the size of the ventral dendrite of the right Mauthner cell under stimulation. These data could be interpreted as evidence of the neuroprotective effect of the Thr–Ser–Lys–Tyr peptide in vivo. 相似文献
53.
S. N. Grishin A. I. Gabdrakhmanov A. E. Khairullin A. U. Ziganshin 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2017,11(4):253-260
The review surveys the impact of “stress hormones”–glucocorticoids and catecholamines–on the functioning of the neuromuscular synapse. The review brings together the data on the influence of the main agents of stress–cortisol and norepinephrine–on the intensity and timing of the acetylcholine release, as well as signaling effect of its co-mediator ATP. 相似文献
54.
The Effect of Acute Unilateral Denervation Injury on Purinergic Signaling in the Cholinergic Synapse
Khairullin A. E. Efimova D. V. Markosyan V. A. Grishin S. N. Teplov A. Yu. Ziganshin A. U. 《Biophysics》2021,66(3):483-486
Biophysics - Previously, we found a change in the efficiency of the modulatory action of ATP under the influence of some non-physiological factors at neuromuscular synapses in rodents. This study... 相似文献
55.
R. F. Khairullin A. G. Mikhailova T. Yu. Sebyakina N. L. Lubenets R. H. Ziganshin I. V. Demidyuk T. Yu. Gromova S. V. Kostrov L. D. Rumsh 《Biochemistry. Biokhimii?a》2009,74(10):1164-1172
A novel trypsin-like protease (PSP) from the psychrotolerant gram-negative microorganism Serratia proteamaculans was purified by ion-exchange chromatography on Q-Sepharose and affinity chromatography on immobilized basic pancreatic trypsin
inhibitor (BPTI-Sepharose). PSP formed a tight complex with GroEL chaperonin. A method for dissociating the GroEL-PSP complex
was developed. Electrophoretically homogeneous PSP had molecular mass of 78 kDa; the N-terminal amino acid sequence 1–10 was determined, and mass-spectral analysis of PSP tryptic peptides was carried out. The
enzyme was found to be the previously unknown oligopeptidase B (OpdB). The S. proteamaculans 94 OpdB gene was sequenced and the producer strain Escherichia coli BL-21(DE3) pOpdB No. 22 was constructed. The yield of expressed His6-PSP was 1.5 mg/g biomass. 相似文献
56.
Yu. A. Zolotarev A. K. Dadayan R. Kh. Ziganshin Yu. A. Borisov V. S. Kozik E. M. Dorokhova B. V. Vaskovsky N. F. Myasoedov 《Russian Journal of Bioorganic Chemistry》2009,35(1):24-32
The reaction of high-temperature solid-state catalytic isotope exchange (HSCIE) between bovine hemoglobin and spillover hydrogen (SH) was studied. It was shown that, in the field of subunit contact, there is a significant decrease in ability for hydrogen exchange by SH. A comparison of the distribution of the isotope label in the hemoglobin α-subunit was carried out for the HSCIE reaction with the hemoglobin complex and with the free α-subunit. To this end, enzymatic hydrolysis of protein under the action of trypsin was carried out. The separation of tritium-labeled tryptic peptides was achieved by HPLC. Changes in availability of polypeptide chain fragments caused by complex formation were calculated using a molecular model. The formation of the protein complex was shown to lead to a decrease in the ability of fragments of α-subunits MFLSFPTTK (A32?40) and VDPVNFK (A93?99) for hydrogen replacement by tritium by almost an order of magnitude; hence, their availability to water (1.4 Å) twice decreased on the average. The decrease in ability to an exchange of hydrogen by spillover tritium on the formation of hemoglobin complex was shown to be connected with a reduction in availability of polypeptide chain fragments participating in spatial interactions of subunits with each other. Thus, the HSCIE reaction can be used not only for the preparative obtaining of tritium-labeled compounds, but also for determining the contact area in the formation of protein complexes. 相似文献
57.
Background
Inbreeding can slow population growth and elevate extinction risk. A small number of unrelated immigrants to an inbred population can substantially reduce inbreeding and improve fitness, but little attention has been paid to the sex-specific effects of immigrants on such "genetic rescue". We conducted two subsequent experiments to investigate demographic consequences of inbreeding and genetic rescue in guppies. 相似文献58.
The yeast strain Geotrichum candidum AN-Z4 isolated from an anthropogenically polluted site was able to transform 2,4,6-trinitrotoluene (TNT) via the formation
of unstable intermediate hydride Meisenheimer complexes with their subsequent destruction and accumulation of nitrite and
nitrate ions as the end mineral forms of nitrogen. Aeration of the medium promoted more profound destruction of this xenobiotic
by the strain G. candidum AN-Z4 than static conditions. The yeast strain was shown to produce citrate, succinate, and isocitrate, which sharply acidified
the medium and influenced the TNT destruction. Two possible pathways of TNT biodegradation were confirmed experimentally:
(1) via the destruction of the TNT-monohydride complex (3-H−-TNT) and (2) via the destruction of one protonated TNT-dihydride complex (3,5-2H−-TNT · H+). The strain G. candidum AN-Z4, due to its ability for TNT degradation, may be promising for bioremediation of TNT-contaminated soil and water. 相似文献
59.
Levels of the Hierarchical Organization of Protein Sequences: An Analysis of Entropy Characteristics
Nekrasov A. N. Kozmin Yu. P. Kozyrev S. V. Esipova N. G. Ziganshin R. H. Anashkina A. A. 《Biophysics》2020,65(6):907-912
Biophysics - A set of 24 647 nonhomologous protein sequences was examined. A pentapeptide occurrence profile was constructed for each sequence and hierarchically organized elements of various sizes... 相似文献
60.
Diabetes mellitus is a heterogeneous metabolic disorder characterized by hyperglycaemia resulting in defective insulin secretion,
resistance to insulin action or both. The use of biguanides, sulphonylurea and other drugs are valuable in the treatment of
diabetes mellitus; their use, however, is restricted by their limited action, pharmaco-kinetic properties, secondary failure
rates and side effects. Trigonella foenum-graecum, commonly known as fenugreek, is a plant that has been extensively used as a source of antidiabetic compounds from its seeds
and leaf extracts. Preliminary human trials and animal experiments suggest possible hypoglycaemic and anti-hyperlipedemic
properties of fenugreek seed powder taken orally. Our results show that the action of fenugreek in lowering blood glucose
levels is almost comparable to the effect of insulin. Combination with trace metal showed that vanadium had additive effects
and manganese had additive effects with insulin on in vitro system in control and diabetic animals of young and old ages using adipose tissue. The Trigonella and vanadium effects were studied in a number of tissues including liver, kidney, brain peripheral nerve, heart, red blood
cells and skeletal muscle. Addition of Trigonella to vanadium significantly removed the toxicity of vanadium when used to reduce blood glucose levels. Administration of the
various combinations of the antidiabetic compounds to diabetic animals was found to reverse most of the diabetic effects studied
at physiological, biochemical, histochemical and molecular levels. Results of the key enzymes of metabolic pathways have been
summarized together with glucose transporter, Glut-4 and insulin levels. Our findings illustrate and elucidate the antidiabetic/insulin
mimetic effects of Trigonella, manganese and vanadium. 相似文献