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91.
Ptitsyn LR Smirnov SV Al'tman IB Samsonova NN Khodiakova AV Vasilenko RN 《Bioorganicheskaia khimiia》1999,25(8):623-629
Expression plasmids containing the synthetic gene hil-4 delta 2 was constructed to produce human interleukin-4 in Escherichia coli cells. Strains TG1 (pBTIL-4 delta 2) and BL21 (DE3) (pETIL-4 delta 2) produced the recombinant protein as inclusion bodies, and its production level was up to 30% of the total cell protein. The renatured hIL-4 delta 2 inhibited IL-4-stimulated T cell proliferation, and this effect was enhanced by cyclosporin A. 相似文献
92.
The feasibility of rendering erythrocytes magnetic and thereby creating magnetic biosorbents (MB Ss) through room temperature exposure to 25-37% iron (II) sulfate solution for 48 +/- 2 h, followed by exposure to 15-35% ammonia water solution for 48 +/- 2 h (with drying after each procedure) was demonstrated. The feasibility of immobilizing ligands on magnetic erythrocytes (ME) and obtaining biological magnetic immunosorbents (BMISs) for further use in EIAs for plague and tularemia antigens was demonstrated. The sensitivity of EIAs involving BMISs amounted to 10 ng/ml and 100 microbial cells per 1 ml. The relative error did not exceed 8%. 相似文献
93.
Basova LV Il'ina NB Vasilenko KS Tiktopulo EI Bychkova VE 《Molekuliarnaia biologiia》2002,36(5):891-900
Cytochrome b5 is a membrane protein that comprises two fragments: one is water-soluble and heme-containing, and the other is hydrophobic and membrane-embedded. The function of electron transfer is performed by the former whose crystal structure is known; however, its conformational states when in the membrane field and interacting with other proteins are still to be studied. Previously, we proposed water-alcohol mixtures for modeling the effect of membrane surface on proteins, and used this approach to study the conformational behavior of positively charged cytochrome c as well as relatively neutral retinol-binding protein also functioning in the field of negatively charged membrane. The current study describes the conformational behavior of the negatively charged water-soluble fragment of cytochrome b5 as dependent on pH. Decreasing pH was shown to transform the fragment state from native to intermediate, similar to the molten globule reported earlier for other proteins in aqueous solutions: at pH 3.0, the fragment preserved a pronounced secondary structure and compactness but lost its rigid tertiary structure. A possible role of this intermediate state in cytochrome b5 functioning is discussed. 相似文献
94.
Konstantinova IM Wetzker R Burova EB Vasilenko KP Turoverova LV Volkova IV Ivanova VA Teslenko LV Nikol'skiĭ NN 《Tsitologiia》1998,40(11):954-957
Here we demonstrate that the epidermal growth factor (EGF) induces association of prosomes (20S-proteasomes) with its receptor in A-431 cells. Additionally, ligand-dependent association of ribonucleoprotein particles (alpha-RNP), containing small ALU-like RNA, with the EGF receptor was demonstrated. A suggestion has been put forward on the involvement of prosomes and alpha-RNP in the EGF signal transmission to different stages of gene expression. 相似文献
95.
Somatic embryos initiate and develop from single mesophyll cells in in vitro cultured leaf segments of orchardgrass ( Dactylis glomerata L.). Segments were plated at time periods ranging from 21 to 0·9 d (21 h) prior to launch on an 11 d spaceflight (STS-64). Using a paired t -test, there was no significant difference in embryogenesis from preplating periods of 14 d and 21 d. However, embryogenesis was reduced by 70% in segments plated 21 h before launch and this treatment was significant at P = 0·0001. The initial cell divisions leading to embryo formation would be taking place during flight in this treatment. A higher ratio of anticlinal:periclinal first cell divisions observed in the flight compared to the control tissue suggests that microgravity affects axis determination and embryo polarity at a very early stage. A similar reduction in zygotic embryogenesis would reduce seed formation and have important implications for long-term space flight or colonization where seeds would be needed either for direct consumption or to grow another generation of plants. 相似文献
96.
SORAYA C M LEAL-BERTIOLI ALETÉIA V PASCOAL PATRÍCIA M GUIMARÃES MARIA F GROSSI DE SÁ REJANE L GUIMARÃES DAMARES C MONTE DAVID J BERTIOLI 《The Annals of applied biology》2003,143(3):349-357
The protein Tarin 1, from Colocasia esculenta, was expressed in Nicotiana tabacum. Bioassays were done on plants expressing Tarin 1 at different levels using Spodoptera frugiperda larvae, various bacteria and fungi and the root‐knot nematode Meloidogyne javanica. It was found that S. frugiperda larvae fed on transformed plants had retarded and lower pupation, lower accumulated biomass and higher mortality rate than larvae fed on control plants. Also, Tarin 1 was found to inhibit the growth in vitro of Pseudomonas syringae pv. tomato. For Meloidogyne javanica, both relative replication and root damage were greater in control plants than in transformed plants, but the results were not statistically significant. This work illustrates the effects of plants expressing Tarin 1, on the growth and development of insects and bacteria, and shows its potential for pest management. 相似文献
97.
The targeted isometric force steps developed by a human wrist after an acoustic signal under conditions of regular repetition and random alternation (the Reg and Rnd modes) of three visually presented target levels (25 N, 35 N, and 50 N) were studied. The main components (MC) and postcorrections could be easily differentiated in the majority of the force trajectories (FT). Analysis of MC parameters has shown that the Rnd mode in comparison with the Reg one is characterized by a noticeable increase in mean amplitude errors of MC with respect to the target level; as a rule, mean errors were positive for the 25 N target level and negative for the 50 N level. An increase in the amplitude variability and a weaker correlation of the force amplitude and the peak value of the first force derivative by time (the maximum rate of the force increase) were also typical of the Rnd mode. It is concluded that when duration of force development is not limited from above, the motor program of such reaction (especially in the Rnd mode) is more liberal than in the case of limitations [5, 12]: values of the force increase rate, specified by the central program, determine the force amplitude in a less rigid manner. Program transferring, i.e., the use of the central program of a fast ballistic movement to make a fast isometric force step, is regarded as a possible reason for the above-mentioned discrepancy; the rigidity of the program of the fast movement is regarded to be determined by corresponding biomechanical limitations. Correlations of the amplitudes and durations of the FT MC varied a great deal for different tested persons and in different modes, but there was a substantial positive correlation in the majority of cases. This finding contradicts the widespread notions about principles of scaling, when scaling of some parameters and maintenance of other parameters of targeted motor reactions as invariants are postulated. Correspondence of the resulting data to the concept of the generalized motor programs and its modifications is discussed.Neirofiziologiya/Neurophysiology, Vol. 25, No. 5, pp. 389–399, September–October, 1993. 相似文献
98.
99.
(1) Dipalmitoyl- and dioleoylthionphosphatidylcholine, which are phosphatidylcholine analogues in which the double bonded oxygen of the phosphate group is replaced by a sulfur atom, have been synthesized in 50–60% yields by condensation of diacylglycerol with phosphorus thionchloride in the presence of choline toluene-sulfonate. Dioleoylthionphosphatidylethanolamine has been prepared by the phospholipase D-catalyzed base exchange reaction. (2) Freeze-fracturing of aqueous dispersions of the thionphospholipids reveals that the thionphosphatidylcholines are organized in extended bilayers whereas dioleoylthionphosphatidylethanolamine above 0°C forms the hexagonal HII phase similar to dioleoylphosphatidylethanolamine. The gel → liquid crystalline phase transition of the dipalmitoylthionphosphatidylcholine occurs at 44°C which is only slightly higher than the transition temperature of dipalmitoylphosphatidylcholine which together with other data demonstrates that the thionphospholipids closely resemble the natural phospholipids in physicochemical behaviour. (3) Proton decoupled 31P-NMR spectra of aqueous dispersions of thionphosphatidylcholines have the characteristic asymmetrical line-shape with a low-field shoulder and a high-field peak typical of phospholipids organized in extended bilayers in which the phosphate group can undergo fast axial rotation. The 31P-NMR spectrum of the thionphosphatidylethanolamine in the hexagonal HII phase has a line-shape with a reversed asymmetry and an effective chemical shift anisotropy half of that of thionphospholipids organized in bilayers which is caused by fast lateral diffusion of the lipids around the cylinders of the hexagonal HII phase as has been observed for the corresponding phosphatidylethanolamines. (4) Since the 31P-NMR resonance of the thionphospholipids is completely separated from that of natural phospholipids, these lipids can be used to study by 31P-NMR the motional and structural properties of individual lipids in mixed systems. This is demonstrated for various lipid mixtures in which non-bilayer lipid structures have been induced by variations in composition, temperature and presence of divalent cations. It is shown that bilayer → non-bilayer transitions can be modulated by gel → liquid crystalline phase transitions and that typical bilayer forming lipids can be incorporated into non-bilayer structures such as the hexagonal HII phase. 相似文献
100.
Jacob V Jacob P Meckbach R Romanov SA Vasilenko EK 《Radiation and environmental biophysics》2005,44(2):119-129
Lung cancer mortality among 5058 male workers of the Mayak Production Association has been analyzed with emphasis on the interaction
of smoking and radiation exposure by using the two-step clonal expansion (TSCE) model of carcinogenesis. The cohort consists
of all Mayak workers with known smoking status, who were employed in the period 1948–1972, and who either had the plutonium
concentration in urine measured or who worked in the reactors, where plutonium exposure was negligible. Those who died during
the first two years after the first urine sampling were excluded. The follow-up extended until the end of 1998. During this
time, 2176 workers died, including 244 lung cancer cases. Mayak workers were exposed to external (gamma and neutron) radiation,
and in the radiochemical and plutonium plants to plutonium. In the preferred TSCE model, internal radiation and smoking act
on the clonal expansion of pre-carcinogenic clones. Assuming a plutonium radiation weighting factor of 20, the excess relative
risk per lung dose was estimated to be 0.11 (95% CI: 0.08; 0.17) Sv−1. Most of the lung cancer deaths are found to be due to smoking. The second main factor is the interaction of smoking and
internal radiation. The model is sub-multiplicative in relative risks due to smoking and radiation. In a multiplicative version
of the TSCE model, internal radiation acts on initiation and transformation rates. This model version agrees with conventional
epidemiological risk models, because it also suggests a higher risk estimate than the preferred TSCE model. However, it fits
the data less well than the preferred model.
An erratum to this article can be found at 相似文献