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1.
Translated from Matematicheskie Zametki, Vol. 49, No. 6, pp. 92–97, June, 1991. 相似文献
2.
Russian Chemical Bulletin - 相似文献
3.
Zn and Pd complexes of meso-tetraphenyltetranaphthaloporphyrins (Ph(4)TNP) exhibit strong infrared absorption bands and luminesce in solutions at room temperature. S1 --> S0 fluorescence (lambda(max) = 732 nm, phi = 5.3%) is the predominant emission in the case of ZnPh(4)TNP (1). This emission is in part due to the delayed fluorescence (phi = 1.1%). Phosphorescence (T1 --> S0) of 1 (lambda(max) = 973 nm) is very weak (phi = 0.04%) and occurs with lifetime of about 440 micros in deoxygenated DMF. In the case of PdPh(4)TNP (2), almost no S1 --> S0 fluorescence could be observed, while the main emission detected was T1 --> S0 phosphorescence (lambda(max) = 938 nm). The phosphorescence of 2 occurs with lifetime of about 65 micros and (phi=6.5%) in deoxygenated DMF solution. Metalloporphyrins 1 and 2 are promising near infrared dyes biomedical applications. 相似文献
4.
Perfluorolefines at cathodic reduction or with one- electron donor reagent (C10H8Na) in aprotic solvents undergo to the defluorination with formation of new double bonds. Such defluorination in the case of perfluoro-2-methylpentene- 2 (I) is accompanied by the dimerization and cyclization producing cyclo-butene C12F22 (II) and diene Cl2F20 (III) in 40 to 70% yields. The proposed reaction scheme includes the next steps: (a) - the successive two- electron transfer on olefine with elimination of F? and formation of the anion (IV); (b) - the nucleophilic attack of the double bond by IV and the following cyclization giving olefine (V); (c) - the isomerization of V into the more stable butene II and/of (d) - the furthur reduction and defluorination of V.The nucleophilic isomerization of V is a main process at electrolysis of I in the presence of fluoride ion at low current density (II:III = 10:1). The furthur defluorination becomes preferable pathway when electrolysis of I is carried out at high current density and with Et4NBF4 as a supporting electrolyte (II:III = 1:9).I undergoes similar defluorination and coupling reactions with some three-valent phosphorus compounds. However, the structure of VI occurs to be different from II and so the coupling reaction via nucleophilic addition (e) leads to another products as compared with the electron-transfer reactions. 相似文献
5.
6.
L. V. Batog V. Yu. Rozhkov M. I. Struchkova A. S. Kulikov N. N. Makhova 《Russian Chemical Bulletin》2013,62(6):1391-1394
[3+2] Cycloaddition of azide groups of N,N′-bis(4-azidofurazan-3-yl)methylenediamine to 1,3-dicarbonyl compounds and malonodinitrile was shown to proceed regioselectively with the formation of the corresponding N,N′-bis[4-(1H-1,2,3-triazol-1-yl)furazan-3-yl]methylenediamine derivatives. The reactions of N,N′-bis(4-azidofurazan-3-yl)methylenediamine with cyanoacetic acid ethyl ester and amide led to the formation of the product of transformation of the azide group in the starting compound to the amino groups. 相似文献
7.
Rozhkov A. V. Sboychakov A. O. Khokhlov D. A. Rakhmanov A. L. Kugel K. I. 《JETP Letters》2020,112(11):725-733
JETP Letters - Studies of a recently suggested mechanism for the stabilization of half-metallic states in doped systems with the nesting of Fermi surface sheets are briefly reviewed. The... 相似文献
8.
I. V. Grekhov L. S. Kostina A. V. Rozhkov N. F. Zitta V. I. Matveev 《Technical Physics》2008,53(12):1609-1614
The static parameters of and switching transients in an advanced high-voltage high-speed switching device—a MOSFET-controlled
integrated thyristor—and their dependences on the geometry and electrophysical properties of base layers in the n
+
pnn’p
+ device structure are studied experimentally. It is shown that the residual resistance of the high-voltage (∼2.5 kV) microthyristor
chip in the on-state is much smaller than that of the high-voltage IGBT with the speed of the former kept at a sufficiently
high level. The new device is multifunctional and can operate under different operating conditions. Specifically, it can be
turned off by shunting the n
+
p emitter by an add-on MOSFET, by applying a gate current pulse, and in the cascode turn-off regime. In these regimes, the
ultimate value of the turn-off current noticeably grows. 相似文献
9.
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