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11.
Structural changes in fibroin molecules upon transformation of the secret into a fiber were studied by the methods of birefringence in a longitudinal hydrodynamic field, optical rotatory dispersion, and circular dichroism. Fibroin fibers were obtained by drawing out the secret from the silk-secreting gland of silkworm moth Bombux mori. In this process, the formation of a longitudinal hydrodynamic field inside the gland was observed. The experimental data obtained make it possible to assess the degree of orientation and unfolding of macromolecules, as well as the conditions of the alpha-beta structural transition in fibroin chains. 相似文献
12.
Regulation of animal oocyte maturation is hypothesized to involve heterotrimeric G-proteins. It is difficult to test this hypothesis though without knowing what G-proteins are present in these cells and where are they localized. We set out to test the hypothesis that G-proteins regulate maturation in the sea urchin oocyte by identifying resident G-proteins in oocytes and eggs, and then investigating their function. We find four families of G-protein alpha-subunits (Galphai, Galphaq, Galphas, and Galpha12) present in both oocytes and eggs of the sea urchin. Three of them, Galphai, Galphaq, and Galphas are present on the plasma membrane of the oocyte, while the fourth is located on cytoplasmic vesicles. Upon oocyte maturation, these proteins remain in eggs, and continue to be expressed in embryonic tissues. To test the functional contribution of the G-proteins to the regulation of oocyte maturation, we employ specific intervening reagents, including antibodies and competitor peptides to each Galpha subunit, and specific Galpha toxins. We find that Gi is a main candidate for a positive regulator of sea urchin oocyte maturation. These studies provide a foundation to further test specific hypotheses of the G-protein mediated regulation of oocyte maturation, fertilization, and early development in the sea urchin. 相似文献
13.
Voronina EN Vikhrova MA Khrapov EA Kinsht VN Norkina OV Gorbunova EV Shabaldin AV Glushkov AN Krasnov VA Filipenko ML 《Molekuliarnaia genetika, mikrobiologiia i virusologiia》2004,(3):8-11
KatG Ser3 15Thr mutation is one of the main reasons of resistance to isoniazid in Mycobacterium tuberculosis isolates. The frequency rate of the above mutation among isoniazid-resistant isolates made 94% in Novosibirsk Region and 93% in Kemerovo Region. The use of PCR-restriction fragment length polymorphism (PCR-RFLP) can be regarded as an adequate method for rapid screening of isoniazid resistance in Mycobacterium tuberculosis isolated in the West-Siberian Region. 相似文献
14.
Voronina TA Epshteĭn OI Molodavkin GM Sergeeva SA Kraĭneva VA 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2003,43(3):291-293
Proproten contains ultra-low doses of affinity purified antibodies to S-100 protein dynamized according to the rules of homeopathy. S-100 is regulator of brain integrative activity and takes part in synaptic processes. In experiment on outbred rats proproten demonstrates significant anxiolytic, antidepressant and antiamnestic effects after single and repeated administration. Proproten is similar to the well-known reference preparations diazepam, amitriptyline and piracetam in activity. Proporten's advantage over these drugs is no sedative, myorelaxation and amnestic effects. Psychotropic effects of proproten are likely to result from modulation of synaptic transmission in limbic structures of brain. 相似文献
15.
An electrophoretically homogeneous preparation of the NAD kinase activating factor was isolated from rabbit liver and its physico-chemical properties were investigated. The similarity of molecular weights of the activator subunit and hexamer, pI values, the number of SH-groups to the corresponding parameters for glutamate dehydrogenase and the glutamate dehydrogenase activity demonstrated by this factor allowed for the identification of the NAD kinase activating factor as glutamate dehydrogenase. Using three independent methods, the formation of the NAD kinase--glutamate dehydrogenase complex was shown. Both the oligomeric and monomeric (subunit) forms of NAD kinase were found to be able to form complexes with glutamate dehydrogenase. 相似文献
16.
N. A. Ermolenko U. A. Boyarskikh A. G. Sushko E. N. Voronina I. A. Selezneva T. V. Sinkina A. F. Lazarev V. D. Petrova M. L. Filipenko 《Russian Journal of Genetics》2010,46(12):1486-1491
The frequencies of the polymorphic gene variants MnSOD Ala9Val, GPX1 Pro198Leu, and GSTP1 Ile105Val were estimated in female residents of Altai krai with breast cancer. The frequency distributions of the genotypes for
all genes studied in both patients and control subjects fit the Hardy-Weinberg equilibrium. The estimated frequencies of the
genotypes for the studied genes in the control group did not differ from those earlier reported for Caucasoid women living
in Europe. The T (rs1050450) allele of the GPX1 gene was demonstrated to protect against sporadic breast cancer (OR = 0.74 (95% CI = 0.58−0.94), p = 0.012). Carriers of the genotype combination MnSOD CC + GPX1 CC were found to have a 1.6 times higher risk of sporadic breast cancer compared to the control group (OR = 1.59 (1.05−2.41),
p = 0.0258). The polymorphic loci GSTP1 (rs1695) and MnSOD (rs4880) were not found to be significantly associated with the risk of familial or sporadic breast cancer. 相似文献
17.
Structures and functions of about 700 oligopeptides of various plants are presently known. However, only one polypeptide has
been isolated from grapes and characterized. At the same time, tens of thousands of uncharacterized amino acid sequences have
been revealed in this plant, among which there can also be precursors of oligopeptide regulators. Due to the scientific and
practical importance of innate immunity of agricultural plants, we have undertaken structural and functional investigation
of these sequences to identify new regulatory oligopeptides including antimicrobial agents. For this purpose, we elaborated
a special method of computer analysis enabling comparison of primary structures of putative precursors of grape oligopeptides
with amino acid sequences of known oligopeptides of other plants. Structural similarity served as the basis for prediction
of potential functional properties. As a result, over 20 new structures of antimicrobial and other grape oligopeptides have
been found. 相似文献
18.
Vaĭner AS Boiarskikh UA Voronina EN Selezneva IA Sinkina TV Lazarev AF Petrova VD Filipenko ML 《Molekuliarnaia biologiia》2010,44(5):816-823
Breast cancer is the most incident cancer among women. We investigated the role of polymorphisms of folate metabolizing genes MTHFR (C677T and A1298C), SHMT1 (C1420T) and MTHFD (G1258A) in genetic susceptibility to this type of cancer. We determined allele and genotype frequencies in case (850 women with sporadic form of breast cancer) and control (810 women) groups. None of these polymorphisms was significantly associated with breast cancer risk. To increase statistical power of our study, we conducted a meta-analysis which included published genotype data and the results of our work. Meta-analysis also revealed no significant association of studied SNPs with breast cancer. 相似文献
19.
20.
An asymmetric fourth cell division in the sea urchin embryo results in formation of daughter cells, macromeres and micromeres, with distinct sizes and fates. Several lines of functional evidence presented here, including pharmacological interference and dominant negative protein expression, indicate that heterotrimeric G protein Gi and its interaction partner, activator of G-protein signaling (AGS), are necessary for this asymmetric cell division. Inhibition of Gi signaling by pertussis toxin interferes with micromere formation and leads to defects in embryogenesis. AGS was isolated in a yeast two-hybrid screen with G alpha i as bait and was expressed in embryos localized to the cell cortex at the time of asymmetric divisions. Introduction of exogenous dominant-negative AGS protein, containing only G-protein regulatory (GPR) domains, selectively prevented the asymmetric division in normal micromere formation. These results support the growing evidence that AGS is a universal regulator of asymmetric cell divisions in embryos. 相似文献