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101.
102.
103.
A hydrophobic uncharged fluorescent probe of 4-dimethylaminochalcone (DMC) interacted with synthetic phospholipid membranes. Comparison of absorption spectra and fluorescence of DMC in the membranes and organic solvents shows that in the membranes the DMC molecules are located not in the hydrocarbon layer but in the polar regions near the surface. The probe is distributed regularly along the surface forming no dimers and clusters. Polar groups which surround the probe in the membrane are less mobile than the molecules of organic solvents at the same temperature. The evaluation shows that the relaxation time of polar groups in the probe environment is longer than 0.15-10(-9) sec. The DMC molecules may be located in different sites of the membrane surface, which seem to differ from one another in the mobility of polar groups. 相似文献
104.
105.
A model is proposed that allows one to reveal specific features of the biosystem dynamics based on competitive processes of
binary interaction. The model assumes a two-level hierarchy of system organization. Objects at the lower level of a system
being investigated interact in a random way. The upper level determines the modulation of the development of a random process
at the lower level. The application of the results of modeling to processes such as oxygen transport by proteins, adaptation
of living organisms to changing environmental conditions, muscle contraction, and adaptability to stresses is discussed. 相似文献
106.
Content of primary (diene conjugates), secondary (ketodienes), end (Schiff's bases) products of free radical oxidation (FRO) of lipids was determined, as well as content of total and non-protein-bound thiols in human lens at different stages of cataractogenesis. Lens opacity was estimated by quantitative morphometric analysis. Participation of FRO of lipids in lens opacity is proved. It is shown that total thiols of lens fibres are rapidly inactivated when the intensity of lipid FRO is increased at the expense of the fall of glutathione level. These processes promote the formation of high molecular protein aggregates in the lens and cataract development. Coefficients of linear correlation between the indicated parameters are presented. A conclusion is drawn concerning possible prevention of cataract development by decreasing the level of accumulation of lipid peroxides and by maintaining high concentration of reduced glutathione in the lens. 相似文献
107.
Freĭdin MB Bragina EIu Fedorova OS Deev IA Kulikov ES Ogorodova LM Puzyrev VP 《Molekuliarnaia biologiia》2011,45(3):464-472
Genome-wide association studies are currently considered as one of the most powerful tools to establishing the genetic basis of complex diseases. A number of such studies were carried out for allergic diseases; however, in Russian population this analysis has not been performed so far. For the first time, we performed genome-wide association study of allergic diseases in Russian inhabitants of Western Siberia. Two new loci associated with childhood bronchial asthma were identified (20q13.12, rs2425656, P = 1.99 x 10(-7); 1q32.1, rs3817222, rs12734001, P = 2.18 x 10(-7) and 2.79 x 10(-7), respectively) as well as one locus, associated with allergic rhinitis (2q36.1, rs1597167, P = 3.69 x 10(-7)). Genes located in the loci, YWHAB and PPP1R12B for asthma and KCNE4 for allergic rhinitis, are new genes for these diseases. It was found that BAT1 (6p21.33), MAGI2 (7q21.11) and ACPL2 (3q23) genes are, likely, common (syntropic) genes of allergic disease and a topic sensitisation. It was shown that RIT2 (18q12.3) and (5q31.1) genes can be involved in the control of lung function. The results of the study enlarge the body of data on genetic factors of allergy and expand the list of genes underlying these diseases. 相似文献
108.
The method of affinity coelectrophoresis was used to study the binding of
nine representative glycosaminoglycan (GAG)-binding proteins, all thought
to play roles in nervous system development, to GAGs and proteoglycans
isolated from developing rat brain. Binding to heparin and non-neural
heparan and chondroitin sulfates was also measured. All nine
proteins-laminin-1, fibronectin, thrombospondin-1, NCAM, L1, protease
nexin-1, urokinase plasminogen activator, thrombin, and fibroblast growth
factor-2-bound brain heparan sulfate less strongly than heparin, but the
degree of difference in affinity varied considerably. Protease nexin-1
bound brain heparan sulfate only 1.8- fold less tightly than heparin
(Kdvalues of 35 vs. 20 nM, respectively), whereas NCAM and L1 bound heparin
well (Kd approximately 140 nM) but failed to bind detectably to brain
heparan sulfate (Kd>3 microM). Four proteins bound brain chondroitin
sulfate, with affinities equal to or a few fold stronger than the same
proteins displayed toward cartilage chondroitin sulfate. Overall, the
highest affinities were observed with intact heparan sulfate proteoglycans:
laminin-1's affinities for the proteoglycans cerebroglycan (glypican-2),
glypican-1 and syndecan-3 were 300- to 1800-fold stronger than its affinity
for brain heparan sulfate. In contrast, the affinities of fibroblast growth
factor-2 for cerebroglycan and for brain heparan sulfate were similar.
Interestingly, partial proteolysis of cerebroglycan resulted in a >400-
fold loss of laminin affinity. These data support the views that (1)
GAG-binding proteins can be differentially sensitive to variations in GAG
structure, and (2) core proteins can have dramatic, ligand-specific
influences on protein-proteoglycan interactions.
相似文献
109.
The effect of relaxed functional constraints on the photosynthetic gene rbcL in photosynthetic and nonphotosynthetic parasitic plants 总被引:1,自引:0,他引:1
The photosynthetic gene rbcL has been lost or dramatically altered in some
lineages of nonphotosynthetic parasitic plants, but the dynamics of these
events following loss of photosynthesis and whether rbcL has sustained
functionally significant changes in photosynthetic parasitic plants are
unknown. To assess the changes to rbcL associated with the loss of
functional constraints for photosynthesis, nucleotide sequences from
nonparasitic and parasitic plants of Scrophulariales were used for
phylogeny reconstruction and character analysis. Plants in this group
display a broad range of parasitic abilities, from photosynthetic
("hemiparasites") to nonphotosynthetic ("holoparasites"). With the
exception of Conopholis (Orobanchaceae), the rbcL locus is present in all
parasitic plants of Scrophulariales examined. Several holoparasitic genera
included in this study, including Boschniakia, Epifagus, Orobanche, and
Hyobanche, have rbcL pseudogenes. However, the holoparasites Alectra
orobanchoides, Harveya capensis, Harveya purpurea, Lathraea clandestina,
Orobanche corymbosa, O. fasciculata, and Striga gesnerioides have intact
open reading frames (ORFs) for the rbcL gene. Phylogenetic hypotheses based
on rbcL are largely in agreement with those based on sequences of the
nonphotosynthetic genes rps2 and matK and show a single origin of
parasitism, and loss of photosynthesis and pseudogene formation have been
independently derived several times in Scrophulariales. The mutations in
rbcL in nonparasitic and hemiparasitic plants would result in largely
conservative amino acid substitutions, supporting the hypothesis that
functional proteins can experience only a limited range of changes, even in
minimally photosynthetic plants. In contrast, ORFs in some holoparasites
had many previously unobserved missense substitutions at functionally
important amino acid residues, suggesting that rbcL genes in these plants
have evolved under relaxed or altered functional constraints.
相似文献
110.
Moskalenko AV Kukushkin NI Starmer CF Deev AA Kukushkina KN Medvinskiĭ AB 《Biofizika》2001,46(2):319-329
A new approach to the analysis of variability of electrocardiograms (ECGs) typical of polymorphic arrhythmias is developed. In these ECGs, separate QRS complexes can be often hardly identified. As a result, the mathematical methods that have been elaborated hitherto are not suitable for such arrhythmias. The approach presented here is based on the quantitative estimation of the variability of neighboring parts of the ECG. In this case, the necessity of the identification of separate QRS complexes ceases to be significant. Based on this approach, the analysis of normalized ECG variability is developed in the framework of which two indices that characterize the oscillation variability and its changes in time are related to a part of the ECG and/or the ECG as a whole. Variations of these indices allow both the polymorphism of a separate ECG to be estimated and different ECGs to be compared with each other. The method presented may be useful in studies of the mechanisms and in the diagnosis of polymorphic arrhythmias. 相似文献