全文获取类型
收费全文 | 145篇 |
免费 | 5篇 |
出版年
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 9篇 |
2011年 | 6篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 1篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 12篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 46 毫秒
51.
Individuality of distress and discomfort calls in neonates with bass voices: Wild‐living goitred gazelles (Gazella subgutturosa) and saiga antelopes (Saiga tatarica)
下载免费PDF全文
![点击此处可从《Ethology : formerly Zeitschrift fur Tierpsychologie》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ilya A. Volodin Olga V. Sibiryakova Roland Frey Kseniya O. Efremova Natalia V. Soldatova Steffen Zuther Talgat B. Kisebaev Albert R. Salemgareev Elena V. Volodina 《Ethology : formerly Zeitschrift fur Tierpsychologie》2017,123(5):386-396
Neonate ruminants produce distress calls when captured by a predator and discomfort milk begging calls when hungry. In many neonate ruminants, the distress and discomfort calls are high‐frequency vocalizations, in which the fundamental frequency is the key variable for recognition of their emotional arousal by caregivers. In contrast, in this study, we examine the low‐frequency open‐mouth distress and discomfort calls in the neonates of two species of wild‐living ungulates, which clearly highlight vocal tract resonances (formants). In the goitred gazelle (Gazella subgutturosa), the distress calls were higher in fundamental frequency (f0) and in the first and third formants than the discomfort calls. The accuracy of classifying individuals by variables of distress calls with discriminant function analysis (67%) was significantly lower than that of discomfort calls (85%). In the saiga (Saiga tatarica), only the third formant was higher in the distress calls than in the discomfort calls. The accuracy of classifying individuals by variables of distress calls (89%) did not differ significantly from that of discomfort calls (94%). Thus, the use of acoustic cues to vocal identity and to the degree of arousal differs between the two species. Calls were significantly more individualistic in the saiga, probably because this species lives in large herds and neonates use a ‘following’ antipredatory strategy, in which vocal individuality is crucial for mother–offspring communication. In contrast, goitred gazelles live in smaller groups and neonates use a ‘hiding’ antipredatory strategy. Accordingly, mothers can rely on additional environmental cues for spotting their young and this may decrease the necessity for individualization of the calls of neonates. 相似文献
52.
53.
E M Sorokina E V Zhavoronkova N V Efremova I N Topchieva B I Kurganov 《Biochemistry. Biokhimii?a》1999,64(6):665-670
Hydrolysis of N-trans-cynnamoylimidazole catalyzed by conjugates and complexes of alpha-chymotrypsin (ChT) with poly(ethylene glycol) (PEG) of different molecular mass (from 300 to 5000 daltons) was studied in the system of the hydrated reversed micelles of aerosol OT (AOT) in octane at 25 degrees C. The plot of the deacylation constant k3 for PEG--ChT conjugates and complexes versus the degree of hydration of reversed micelles (w0 = [H2O]/[AOT]) was studied. These plots are bell-shaped with maxima shifted to higher degrees of micelle hydration compared to the corresponding value of the shift for ChT. As for PEG--ChT conjugates, the value of the shift of w0 increases with increasing of molecular mass of the attached PEG and/or with the number of polymer chains per ChT molecule. Another picture was observed for PEG--ChT complexes for which the position of the maximum on k3 versusw0 curves was practically the same for all compounds. The values of the thickness of the polymer layer for PEG--ChT conjugates and complexes were calculated. Thus, polymer chains in conjugates placed in hydrated micelles are highly packed, whereas in the case of complexes they form a flat layer on the surface of the protein. 相似文献
54.
Sofia M Efremova Valeria B Itskovich Valentina Parfenova Valentin V Drucker Werner E G Müller Heinz C Schr?der 《Cellular and molecular biology, including cyto-enzymology》2002,48(4):359-371
Lake Baikal is considered as a unique place to study evolution. In this review, we report on recent data on the evolution of endemic freshwater sponges of this ancient lake. Nucleotide sequence data support the idea that these sponges are of monophyletic origin and evolved from Spongillidae. Baikalian sponges form the dominating biomass in the benthos of the lake. Data on the expression of the biomarker heat shock protein 70, revealed that the endemic sponge species of Lake Baikal are useful as bioindicators to assess the anthropogenic impact on the lake. 相似文献
55.
V N Efremova L A Kuz'mina I Ia Moshiashvili 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(3):16-19
An experiment on guinea pigs immunized with staphylococcal vaccine prepared from water-soluble antigens revealed that the degree of developing sensitization and specific resistance was essentially determined by the method and schedule of the administration of the preparation. The intranasal administration of the vaccine induced a lesser degree of sensitization in comparison with its subcutaneous injection. The optimum response to the administration of the vaccine (a low sensitization level and a high degree of protection from infection) was observed in the animals immunized first intranasally and then by subcutaneous injection. The subcutaneous injection of the preparation in combination with its subsequent intranasal application induced a more pronounced degree of sensitization and a lesser degree of protection from infection. 相似文献
56.
The effect of Mycoplasma salivarium on the numerical and structural karyotypic variability was studied in the markerless cell line of Indian muntjac skin fibroblasts
(line M) during long-term cultivation with and without L-arginine. The cultivation of mycoplasma-contaminated cells for 15
and 30 days did not change the character of cell distribution for the number of chromosomes. In contaminated cells cultivated
for 60 and 75 days, the character of cell distribution for the chromosome number changed. These changes involve bimodal distribution
for the chromosome number due to a significant decrease in frequency of the cells with the modal number of chromosomes with
the main structural variant of karyotype (SVK) 2 + 2 + 1 + 1 + 1 and an increase in the frequency of cells with the submodal
number of chromosomes with a main SVK of 2 + 2 + 1 + 1. Furthermore, a significant increase in the frequency of cells with
lower numbers of chromosomes was observed after 60 days compared to that after 75 days of cultivation. After the cultivation
of the contaminated and control cells in the medium with an elevated concentration of L-arginine for 60 days, the numerical
parameters were unchanged relative to the control. The cultivation of contaminated cells for 60 days followed by the addition
of L-arginine for 15 days restored the numerical parameters to the control level. In the contaminated cells, the frequency
of chromosomal aberrations for 30, 60, and 75 days increased significantly compared to the control variant. After 30 days
of cultivation, a small but statistically significant increase took place due to a uniform slight increase in the frequency
of chromosomal aberrations of all types. After 60 and 75 days, a greater increase occurred due to a statistically significant
increase in the frequency of chromosomal and chromatid breaks. Moreover, after 60 days, the level of dicentrics (telomeric
associations) mainly produced by chromosomes 1 and 2 increased significantly. The role of dicentrics as for a means of adaptation
for markerless cell lines to the condition of cultivation and the role of L-arginine in the restoration of the normal karyotypic
structure of the line M cell population at mycoplasmal contamination are discussed. 相似文献
57.
58.
T M Efremova A T Morozov V P Markin 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1979,29(5):938-947
EEG power spectra of the sensorimotor area of the neocortex, the dorsal hippocampus, midbrain reticular formation and anteroventral thalamic nucleus, as well as corresponding coherence functions and phase spectra, undergo changes during formation and performance of defensive conditioned reflex in rabbit. The conclusion is draen that in the process of conditioning a morphofunctional system of brain structures is established including the above mentioned formations. Their functional integration occurs on the basis of theta-rhythm. The execution of a conditioned act requires isorhythmicity of electrical processes within the theta-range in the studied structures and an adequate level of their excitability, which is manifested in the dominance of 6,0 c/s frequency. 相似文献
59.
Alexandru Movila Helen V. Dubinina Natalia Sitnicova Liubov Bespyatova Inga Uspenskaia Galina Efremova Ion Toderas Andrey N. Alekseev 《Experimental & applied acarology》2014,63(1):65-76
Characterizing the tick-borne microorganism communities of Ixodes ricinus (sheep tick) and Ixodes persulcatus (taiga tick) from the I. ricinus species complex in distinct geographical regions of Eastern Europe and European Russia, we demonstrated differences between the two ticks. Taiga ticks were more frequently mono- and co-infected than sheep ticks: 24.4 % (45/184 tested ticks) versus 17.5 % (52/297) and 4.3 % (8/184) versus 3.4 % (10/297), respectively. Ginsberg co-infection index values were significant at the various sites. Diversity of the tick-borne microorganism communities was estimated by the Shannon index, reaching values of 1.71 ± 0.46 and 1.20 ± 0.15 at the sheep-tick and the taiga-tick harbored sites, respectively. Richness of the tick-borne microorganism community in the sheep tick collection sites was about twice the value of the taiga tick collection sites. Future investigations are warranted to further characterize the peculiarities of the tick-borne microorganism communities among the ticks of the Ixodes ricinus complex. 相似文献
60.
The genomic organization of Triticum timopheevii (2n=28, AtAtGG) was compared with hexaploid wheat T. aestivum (2n=42, AABBDD) by comparative mapping using microsatellites derived from bread wheat. Genetic maps for the two crosses T. timopheevii var. timopheevii × T. timopheevii var. typica and T. timopheevii K-38555×T. militinae were constructed. On the first population, 121 loci were mapped, and on the second population 103 loci. The transferability
of the wheat markers to T. timopheevii was generally better for the A genome-specific markers (76–78% produced amplification products; 26 and 29% were polymorphic)
than for B genome-specific markers (54% produced amplification products; 14 and 16% were polymorphic). Of the D genome-specific
markers, one third produced amplification products in T. timopheevii, but only 5 and 2% were polymorphic in the corresponding mapping populations. The maps constructed confirmed the previously
described translocation between chromosome arms 6AtS and 1GS and revealed at least two yet unknown rearrangements on chromosomes 4At and 6At. The presence of other translocations and rearrangements between T. timopheevii and T. aestivum was demonstrated by a variety of markers mapping to nonhomoeologous positions. 相似文献