全文获取类型
收费全文 | 542篇 |
免费 | 9篇 |
出版年
2022年 | 6篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 15篇 |
2016年 | 15篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 22篇 |
2012年 | 21篇 |
2011年 | 16篇 |
2010年 | 18篇 |
2009年 | 7篇 |
2008年 | 23篇 |
2007年 | 23篇 |
2006年 | 19篇 |
2005年 | 24篇 |
2004年 | 14篇 |
2003年 | 9篇 |
2002年 | 18篇 |
2001年 | 14篇 |
2000年 | 19篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1992年 | 5篇 |
1990年 | 5篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 15篇 |
1978年 | 4篇 |
1976年 | 6篇 |
1975年 | 11篇 |
1974年 | 18篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1971年 | 13篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 8篇 |
1967年 | 9篇 |
1966年 | 9篇 |
1965年 | 3篇 |
排序方式: 共有551条查询结果,搜索用时 15 毫秒
41.
Kuznetsov AN Turkovskiĭ II Paramonov BA Kharin VN Kuznetsova NV Volkova IA 《Biofizika》2004,49(4):727-731
The complex dielectric permittivity of salt solutions with positive and negative salvation as well as healthy and cicatricially changed human skin in situ at the frequencies of 42 and 56.6 GHz was measured. The relation between the dielectric characteristics of water and diluted salt solutions and changes in their structural organization conditioned by different temperatures of samples and the type of salvation of electrolytes was studied. The differences in the dielectric characteristics of healthy and cicatricially changed skin are interpreted in terms of the dependence of the structural organization of interstitial fluids on the morphological and functional state of biological tissues. 相似文献
42.
D. K. Kambarova V. V. Belyaev A. V. Volkova S. G. Oganesyan V. Z. El Salim G. A. Oganesyan 《Journal of Evolutionary Biochemistry and Physiology》2010,46(5):501-510
A possibility is discussed of use of methods of nonlinear dynamics for analysis of spontaneous EEG and of the EEG caused by
low acoustic stimuli in healthy people and in patients with epilepsy. The use of methods of nonlinear dynamics—the fractal
dimension of EEG—in clinical and scientific practice is described. 相似文献
43.
Tatyana O. Anokhina Olga V. Volkova Irina F. Puntus Andrei E. Filonov Vladimir V. Kochetkov Alexander M. Boronin 《Process Biochemistry》2006,41(12):2417-2423
Two IncP-9 naphthalene degradative plasmids pOV17 and pBS216 were transferred into plant growth-promoting Pseudomonas which were represented by species P. aureofaciens, P. chlororaphis, P. fluorescens, and P. putida. The strains with the same plasmid differed significantly by their growth parameters, stability of the plasmid and plant protective effect from naphthalene action. Strains P. putida 53a(pOV17) and P. chlororaphis PCL1391(pOV17) demonstrated higher population number in the rhizosphere. Moreover, they protected the mustard plants from naphthalene toxic influence more effectively than the wild type strain P. aureofaciens OV17(pOV17). The activity of catechol-2,3-dioxygenase in the strains with the plasmid pOV17 was higher than that in strains with the plasmid pBS216. The strain P. putida 53a(pOV17) with high catechol-2,3-dioxygenase activity has been demonstrated to have the best protective effect. The strain P. putida 53a(pBS216) without catechol dioxygenases activities did not have protective effect but suppressed the plant germination. 相似文献
44.
In Agaricus bisporus all cytological studies performed until now concerned the pseudohomothallic and bisporic var. bisporus. In the past 12 y two tetrasporic varieties have been described, the heterothallic var. burnettii and the homothallic var. eurotetrasporus. Our aim was to compare the behavior of the nuclei in the vegetative and reproductive cells of the three varieties with light microscopy (Feulgen and DAPI staining) and transmission electron microscopy. Most of the vegetative cells contained 3-5 nuclei in the three varieties. Nuclear migrations through the septum were detected. In the basidia relative locations of nuclei and vacuoles, meiotic spindle alignments, relative content of nuclear DNA and synaptonemal complexes were measured or observed. From the observation of numerous asynchronous second division of meiosis within basidia of var. bisporus and var. burnettii a new hypothesis emerges to explain the nonrandom distribution of the four meiotic products in the two spores of the bisporic basidia. Karyogamy and meiosis similarly occurred in the three varieties. In the case of A. bisporus var. eurotetrasporus this implies that the reproductive mode is sexual and therefore homothallic in the strict sense. The three different types of life cycles are described. 相似文献
45.
46.
The data on the in vitro and in vivo (into embryonic disk) retroviral-mediated transfer of genetic information into chicken embryonic cells are presented. The estimated transformation frequency of the cultured target cells constituted 8 x 10(-4) to 5 x 10(-3). A transgenic rooster, carrying recombinant DNA in blood, heart, liver, and intestine cells, was obtained. 相似文献
47.
48.
Kobets T Havelková H Grekov I Volkova V Vojtíšková J Slapničková M Kurey I Sohrabi Y Svobodová M Demant P Lipoldová M 《PLoS neglected tropical diseases》2012,6(6):e1667
Background
Leishmaniasis is a disease caused by protozoan parasites of genus Leishmania. The frequent involvement of Leishmania tropica in human leishmaniasis has been recognized only recently. Similarly as L. major, L. tropica causes cutaneous leishmaniasis in humans, but can also visceralize and cause systemic illness. The relationship between the host genotype and disease manifestations is poorly understood because there were no suitable animal models.Methods
We studied susceptibility to L. tropica, using BALB/c-c-STS/A (CcS/Dem) recombinant congenic (RC) strains, which differ greatly in susceptibility to L. major. Mice were infected with L. tropica and skin lesions, cytokine and chemokine levels in serum, and parasite numbers in organs were measured.Principal Findings
Females of BALB/c and several RC strains developed skin lesions. In some strains parasites visceralized and were detected in spleen and liver. Importantly, the strain distribution pattern of symptoms caused by L. tropica was different from that observed after L. major infection. Moreover, sex differently influenced infection with L. tropica and L. major. L. major-infected males exhibited either higher or similar skin pathology as females, whereas L. tropica-infected females were more susceptible than males. The majority of L. tropica-infected strains exhibited increased levels of chemokines CCL2, CCL3 and CCL5. CcS-16 females, which developed the largest lesions, exhibited a unique systemic chemokine reaction, characterized by additional transient early peaks of CCL3 and CCL5, which were not present in CcS-16 males nor in any other strain.Conclusion
Comparison of L. tropica and L. major infections indicates that the strain patterns of response are species-specific, with different sex effects and largely different host susceptibility genes. 相似文献49.
50.
E. A. Arifulin E. E. Bragina V. A. Zamyatnina E. G. Volkova E. V. Sheval’ S. A. Golyshev L. N. Kintsurashvili G. I. Kir’yanov A. N. Prusov V. Yu. Polyakov 《Russian Journal of Developmental Biology》2012,43(2):121-130
Changes in chromatin structure at different stages of differentiation of human spermatids were studied. It was shown that,
in nuclei of early spermatids, chromatin is loosely packed and its structural element is an 8-nm fiber. This “elementary”
fiber is predominant at the initial stages of differentiation; in the course of maturation, it is replaced by globular elements
approximately 60 nm in diameter. In intermediate spermatids, these globules start to condense into fibrillar aggregates and
reduce their diameter to 30–40 nm. At all stages of spermatid maturation, except the final stages, these globules are convergence
centers for elementary fibers. This remodelling process is vectored and directed from the apical (acrosomal) to the basal
pole of the nucleus. In mature spermatids, the elementary 8-nm fibers are almost absent and the major components are 40-nm
fibrillar aggregates. The nuclei of mature spermatids are structurally identical with the nuclei of spermatozoa with the so-called
“immature chromatin,” which are commonly found in a low proportion in sperm samples from healthy donors and may prevail over
the normal cells in spermiogenetic disorders. The cause of this differentiation blockade remains unknown. Possibly, the formation
of intermolecular bonds between protamines, which are required for the final stages of chromatin condensation, is blocked
in a part of spermatids. The results of this study are discussed in comparison with the known models of nucleoprotamine chromatin
organization in human spermatozoa. 相似文献