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251.
Maintaining genetic integrity of coexisting wild and domestic populations: Genetic differentiation between wild and domestic Rangifer with long traditions of intentional interbreeding 下载免费PDF全文
David G. Anderson Kjersti S. Kvie Vladimir N. Davydov Knut H. Røed 《Ecology and evolution》2017,7(17):6790-6802
This study investigates the genetic effect of an indigenous tradition of deliberate and controlled interbreeding between wild and domestic Rangifer . The results are interpreted in the context of conservation concerns and debates on the origin of domestic animals. The study is located in Northeastern Zaba?kal'e, Russia at approximately 57 degrees North latitude. Blood and skin samples, collected from wild and domestic Rangifer , are analyzed for their mtDNA and microsatellite signatures. Local husbandry traditions are documented ethnographically. The genetic data are analyzed with special reference to indigenous understandings of the distinctions between local domestic types and wild Rangifer . The genetic results demonstrate a strong differentiation between wild and domestic populations. Notably low levels of mtDNA haplotype sharing between wild and domestic reindeer, suggest mainly male‐mediated gene flow between the two gene pools. The nuclear microsatellite results also point to distinct differences between regional domestic clusters. Our results indicate that the Evenki herders have an effective breeding technique which, while mixing pedigrees in the short term, guards against wholesale introgression between wild and domestic populations over the long term. They support a model of domestication where wild males and domestic females are selectively interbred, without hybridizing the two populations. Our conclusions inform a debate on the origins of domestication by documenting a situation where both wild and domestic types are in constant interaction. The study further informs a debate in conservation biology by demonstrating that certain types of controlled introgression between wild and domestic types need not reduce genetic diversity. 相似文献
252.
EPR and ENDOR evidence for a 1-His,hydroxo-bridged mixed-valent diiron site in Desulfovibrio vulgaris rubrerythrin 总被引:2,自引:0,他引:2
Smoukov SK Davydov RM Doan PE Sturgeon B Kung IY Hoffman BM Kurtz DM 《Biochemistry》2003,42(20):6201-6208
Key features differentiating the coordination environment of the two irons in the mixed-valent (Fe(2+),Fe(3+)) diiron site of Desulfovibrio vulgaris rubrerythrin (Rbr(mv)) were determined by continuous wave (CW) and pulsed ENDOR spectroscopy at 35GHz. (14)N ENDOR evidence indicates that a nitrogen is bound only to the Fe(2+) ion of the mixed-valent site. Assuming that this nitrogen is from His131Ndelta, the same one that furnishes an iron ligand in the crystal structure of the diferric site, the ENDOR data allow us to specify the Fe(2+) and Fe(3+) positions within the molecular reference frame. In addition, the (1,2)H ENDOR on Rbr(mv) indicates the presence of a solvent-derived aqua/hydroxo ligand bound either terminally or in a bridging mode to Fe(3+) in the mixed-valent site. The relatively large g anisotropy of Rbr(mv) and weak antiferromagnetic coupling, J approximately -8 cm(-)(1) (in the 2JS(1)*S(2) formalism), between the irons is more consistent with a bridging than terminal hydroxo ligand. gamma-Irradiation was used to cryoreduce Rbr at 77 K, thereby producing a mixed-valent diiron site [(Rbr(ox))(mv)] that retains the structure of the diferric site. The EPR spectrum of (Rbr(ox))(mv) was nearly identical to that of the as-isolated or chemically reduced samples. This near identity implies that the structure of the mixed-valent Rbr diiron site is essentially identical to that of the diferric site, except for protonation of the oxo bridge, which apparently occurred via a proton jump from hydrogen-bonded solvent at 77 K. The EPR spectrum of (Rbr(ox))(mv) thus supports the (14)N ENDOR-assigned His131 ligation to Fe(2+) and assignment of the solvent-derived ligand observed in the (1,2)H ENDOR to a hydroxo bridge between the irons of the mixed-valent diiron site. 相似文献
253.
Fine structure of genital atrium, Furman body, distal region of vagina and sac cirrus were investigated. The broad polymorphism of surface microstructures (microtriches) in various parts of copulative apparatus has been revealed. The constitution of prostate glands, being the modified cytons of syncitial epithelium of the intrabursal section of spermaduct wall, is described. Based on obtained and reference data, a comparative morphological analysis of copulative apparatus organization in lowest and highest cestodes was carried out. The hypothesis suggests that evolution of its organization was connected with the reduction of the muscular elements and simultaneous improvement of their managing, their isolation from surrounding parenchyma and development of supporting connective tissue elements. It is shown, that Fuhrmann's body has its own developed muscular system armed with power microtriches and being capable to evaginate into the distal region of vagina. It is supposed that S. gracilis obtains of two different ways of copulation in: by means of cirrus that executes the cross fertilization; and by means of the additional copulative formation--Furman body, which guarantees the self fertilization of worms. 相似文献
254.
255.
Rose scent: genomics approach to discovering novel floral fragrance-related genes 总被引:3,自引:0,他引:3 下载免费PDF全文
Guterman I Shalit M Menda N Piestun D Dafny-Yelin M Shalev G Bar E Davydov O Ovadis M Emanuel M Wang J Adam Z Pichersky E Lewinsohn E Zamir D Vainstein A Weiss D 《The Plant cell》2002,14(10):2325-2338
For centuries, rose has been the most important crop in the floriculture industry; its economic importance also lies in the use of its petals as a source of natural fragrances. Here, we used genomics approaches to identify novel scent-related genes, using rose flowers from tetraploid scented and nonscented cultivars. An annotated petal EST database of approximately 2100 unique genes from both cultivars was created, and DNA chips were prepared and used for expression analyses of selected clones. Detailed chemical analysis of volatile composition in the two cultivars, together with the identification of secondary metabolism-related genes whose expression coincides with scent production, led to the discovery of several novel flower scent-related candidate genes. The function of some of these genes, including a germacrene D synthase, was biochemically determined using an Escherichia coli expression system. This work demonstrates the advantages of using the high-throughput approaches of genomics to detail traits of interest expressed in a cultivar-specific manner in nonmodel plants. EST sequences were submitted to the GenBank database (accession numbers BQ 103855 to BQ 106728). 相似文献
256.
257.
In a computer controlled experiment the electric activity of rabbits right sensorimotor cortex was recorded in the area of the excitation focus produced by the direct current (2 mcA) application. The current was switched on at the 5th, 10th and 15th minutes of experiment only in cases when the mean amplitude of the delta waves exceeded the baseline. The current was switched off at the mean amplitude of the delta waves exceeding the baseline level by 50%. After training some experiments (2-4), rabbits learned to change their functional state in such way that they "avoided" the action of the direct current. 相似文献
258.
259.
R. A. Pavlyugina N. N. Karamysheva D. S. Sakharov V. I. Davydov 《Human physiology》2012,38(4):354-360
Musical accompaniment (of different styles and intensities) of the solution of mathematical logical tasks influenced the time required for their solution. Classical music 35 and 65 dB and rock music 65 and 85 dB in terms of loudness decreased the time of the solution. Louder classical music (85 dB) did not have this effect. Solution of tasks without musical accompaniment led to an increase in coherent values, especially in ??1, ??2, and ?? the frequency bands in the EEG of the occipital cortex. The intrahemispheric and interhemispheric coherences of frontal EEG increased and EEG asymmetry (in the number of Coh connections in the left and right hemispheres) arose during the solution of the tasks accompanied by music. Classical music (35 and 65 dB) caused left-side asymmetry in the EEG. The use of more powerful classical or rock music led to a prevalence of the number of Coh connections in the right hemisphere. 相似文献
260.
Davydov S. G. Dolgov A. N. Katorov A. S. Revazov V. O. Yakubov R. Kh. 《Plasma Physics Reports》2021,47(10):1080-1083
Plasma Physics Reports - Three groups of charged particles are recorded at the impact of the laser radiation pulse with a metal target in a rarefied gas medium. The optical range laser radiation... 相似文献