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81.
Contamination of litter in a broiler grow-out house with Salmonella prior to placement of a new flock has been shown to be a precursor of the flock''s Salmonella contamination further down the production continuum. In the southern USA, broiler grow-out houses are primarily built on dirt pad foundations that are placed directly on top of the native soil surface. Broiler litter is placed directly on the dirt pad. Multiple grow-out flocks are reared on a single litter batch, and the litter is kept in the houses during downtime between flocks. The effects of environmental determinants on conditions in broiler litter, hence Salmonella ecology within it, has received limited attention. In a field study that included broiler farms in the states of Alabama, Mississippi and Texas we assessed Salmonella in broiler litter at the end of downtime between flocks, i.e. at the time of placement of a new flock for rearing. Here we utilized these results and the U.S. General Soil Map (STATSGO) data to test if properties of soil at farm location impacted the probability of Salmonella detection in the litter. The significance of soil properties as risk factors was tested in multilevel regression models after accounting for possible confounding differences among the farms, the participating broiler complexes and companies, and the farms'' geographical positioning. Significant associations were observed between infiltration and drainage capabilities of soil at farm location and probability of Salmonella detection in the litter. 相似文献
82.
Background and Methodology
Various approaches have been used to investigate how properties of farm contact networks impact on the transmission of infectious diseases. The potential for transmission of an infection through a contact network can be evaluated in terms of the basic reproduction number, R 0. The magnitude of R 0 is related to the mean contact rate of a host, in this case a farm, and is further influenced by heterogeneities in contact rates of individual hosts. The latter can be evaluated as the second order moments of the contact matrix (variances in contact rates, and co-variance between contacts to and from individual hosts). Here we calculate these quantities for the farms in a country-wide livestock network: >15,000 Scottish sheep farms in each of 4 years from July 2003 to June 2007. The analysis is relevant to endemic and chronic infections with prolonged periods of infectivity of affected animals, and uses different weightings of contacts to address disease scenarios of low, intermediate and high animal-level prevalence.Principal Findings and Conclusions
Analysis of networks of Scottish farms via sheep movements from July 2003 to June 2007 suggests that heterogeneities in movement patterns (variances and covariances of rates of movement on and off the farms) make a substantial contribution to the potential for the transmission of infectious diseases, quantified as R 0, within the farm population. A small percentage of farms (<20%) contribute the bulk of the transmission potential (>80%) and these farms could be efficiently targeted by interventions aimed at reducing spread of diseases via animal movement. 相似文献83.
G. A. Savchenko T. M. Volkova A. A. Vasilevskii Yu. V. Korol’kova E. V. Grishin Ya. A. Boichouk O. A. Krishtal 《Neurophysiology》2011,42(6):387-391
We examined effects of purotoxin 1 (PT1), a component of the venom of Geolycosa spiders, on a few voltageand ligand-operated ion channels present in the plasma membrane of sensory neurons from the rat
dorsal root ganglia (DRGs). Purotoxin 1 in a 100 nM concentration evoked no changes in ion currents through voltage-operated
sodium, potassium, and calcium channels in the membranes of isolated sensory neurons. This agent was also found to be ineffective
with respect to capsaicin-sensitive receptor-channel complexes (TRPV1). Testing of the effects of PT1 on purinergic receptor-channel
complexes P2X3, P2X2, and P2X2/3 showed that this toxin is a highly selective blocker of exclusively P2X3 receptors. The selectivity
of action of PT1 demonstrated in our experiments shows that it is a unique agent, which opens up new prospects in the studies
of structural/functional peculiarities of receptor-channel complexes P2X3 as a peripheral link of the nociception system. 相似文献
84.
85.
V. D. Lazareva N. E. Bocharova K. E. Volynski T. M. Volkova E. V. Grishin 《Russian Journal of Bioorganic Chemistry》2000,26(4):271-276
α-Latrotoxin (α-LTX) binding sites to functionally active monoclonal antibodies (MA) A4 and A24 were localized using three
approaches: hydrolysis of the toxin followed by theN-terminal sequencing of immunoreactive peptides; the study of antibody interaction with several recombinant α-LTX fragments;
Western immunoblotting of synthetic overlapping peptides (6–8 aa) whose structures correspond to that of the immunoreactive
α-LTX fragment. It was shown that the MA A4 epitope is located within the F234-M294 protein fragment and that MA A24 interacts with the fragment347FDKDIT352. 相似文献
86.
S. V. Bitarishvili P. Yu. Volkova S. A. Geras’kin 《Russian Journal of Plant Physiology》2018,65(3):446-454
We investigated the effect of γ-irradiation (4–50 Gy) of barley seeds (Hordeum vulgare L., cv. Nur) on the content of endogenous phytohormones–stimulators of plant growth and development: indol-3-acetic acid (IAA), indolyl-3-butyric acid (IBA), zeatin and abscisic acid (ABA). The ratio (IAA + IBA + zeatin)/ABA from the third to the seventh day of germination has been measured. It was shown that the changes in the content of phytohormones as a function of the radiation dose were nonlinear. In the dose range of 4–20 Gy, phytohormones balance was changed due to increased content of growth stimulators and decreased ABA content. Using a dose of 50 Gy led primarily to a decrease in the content of growth stimulators and an increase in ABA content, and the ratio (IAA + IBA + zeatin)/ABA shifted toward ABA content. 相似文献
87.
M. B. Oboznaya N. M. Vladimirova M. A. Titova T. D. Volkova D. O. Koroev A. A. Ryabokon’ A. A. Egorov S. S. Rybakov O. M. Vol’pina 《Russian Journal of Bioorganic Chemistry》2008,34(6):674-682
Antibodies to the prion protein (PrP), particularly, monoclonal antibodies, are necessary tools in the diagnostics and study of prion diseases and potential means of their immunotherapy. For the production of monoclonal antibodies, BALB/c mice were immunized by a recombinant bovine PrP. Three stable hybridomas producing antibodies of IgM class were prepared. The antibodies were bound to PrP in a solid-phase enzyme immunoassay and immunoblotting. The epitope mapping accomplished with the use of synthetic peptides showed that an epitope located in region 25–36 of PrP corresponds to one antibody, and epitopes located in region 222–229, to the other two. The antibodies to fragment 222–229 purified by affinity chromatography recognized with a high specificity conglomerates of a pathogenic prion in the brain tissue of cows suffering from spongiform encephalopathy. Thus, in nontransgenic mice, PrP-specific monoclonal antibodies were produced, useful in studies and diagnostics of prion diseases. 相似文献
88.
Boris Yu. Zaslavsky Nicolai N. Ossipov Sergei V. Rogozhin Yurii L. Sebyakin Ludmila V. Volkova Rimma P. Evstigneeva 《生物化学与生物物理学报:生物膜》1979,556(2):314-321
The hemolytic action of a homologous series of β-d-glucopyranosyl-1-alkylphosphates on human erythrocytes has been examined. The agent's affinity for the red cell membrane and the mean number of the agent's molecules which, upon interaction with an erythrocyte, make it undergo hemolysis have been measured. The contribution of the head group and that of a CH2 group of the surfactants to the free energy of the agents' binding to the cell membrane have been estimated. The effect of the surfactants on the red cell volume and the lytic concentrations of the agents have been measured. The contribution of a CH2 group to the free energy of the interaction of the amphiphiles embedded in the membrane bilayer with their environment has been evaluated and is proposed to be used as a measure of the membrane matrix stability. 相似文献
89.
The effects of mutations and genetic background on the mating activity of males and receptivity of females Drosophila melanogaster have been studied at different population densities. Population density, as well as its combinations with other factors, significantly affects mating behavior of D. melanogaster. There are two distinct trends in the effect of this factor on mating behavior: the maximum larval overpopulation may cause either a significant suppression of the behaviors studied or an increase in their expressivity. The mating behaviors of w a and cn mutants against a certain genetic background changed similarly in response to varying population density. 相似文献
90.
Using a patch-clamp technique in the whole-cell configuration, we studied the effect of an exogenous antioxidant, dithiothreitol
(DTT), on transmembrane currents in isolated cells obtained from the rat spinal ganglia. We demonstrated that this antioxidant
(DTT) is capable of modulating the proton-gated current. In most neurons, proton-gated currents increased in the presence
of the antioxidant. Since proton-gated receptor-channel complexes of sensory neurons are involved in different processes of
signalling and transmission of sensory information in the peripheral nervous system, we hypothesize that the influences mediated
by alterations of the concentrations of antioxidants participate in the formation of the state of algesia under normal physiological
conditions and of that of hyperalgesia in pathological states. In addition, oxidative stress, which causes a shift in the
balance of concentrations of antioxidants, accompanies numerous abnormal pathophysiological states, in particular diabetes,
ischemia, and inflammation. Since proton-gated channels are permeable for calcium ions, an antioxidant-induced increase in
calcium signalling can be significantly important for a number of biochemical processes occurring in tissues.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 193–197, May–June, 2006. 相似文献