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11.
12.
We apply the distinction between parameter independence and outcome independence to the linear and nonlinear models of a recent nonrelativistic theory of continuous state vector reduction. We show that in the nonlinear model there is a set of realizations of the stochastic process that drives the state vector reduction for which parameter independence is violated for parallel spin components in the EPR-Bohm setup. Such a set has an appreciable probability of occurrence ( 1/2). On the other hand, the linear model exhibits only extremely small parameter dependence effects. We investigate some specific features of the models and we recall that, as has been pointed out recently, if one wants to be able to speak of definite outcomes (or equivalently of possessed objective elements of reality) at finite times, one has to slightly change the criteria for their attribution to physical systems. The concluding section is devoted to a detailed discussion of the difficulties which one meets when one tries to take, as a starting point for the formulation of a relativistic theory, a nonrelativistic scheme which exhibits parameter dependence. Here we derive a theorem which identifies the precise sense in which the occurrence of parameter dependence forbids a genuinely relativistic generalization. Finally we show how the appreciable parameter dependence of the nonlinear model gives rise to problems with relativity, while the extremely weak parameter dependence of the linear model does not give rise to any difficulty, provided one takes into account the appropriate criteria for the attribution of definite outcomes.Work supported in part by the Trieste Section of the INFN. 相似文献
13.
14.
M. E. Umstead S. A. Lloyd J. W. Fleming M. C. Lin 《Applied physics. B, Lasers and optics》1985,38(4):219-224
The reaction of NO2 with isobutane, induced by 488 nm laser radiation, to form 2-nitro-2-methylpropane has been investigated and the results computer-modeled according to two possible reaction mechanisms. The first scheme involves the direct abstraction of H from isobutane by vibronically excited NO2 (NO
2
*
), and the second, abstraction by an intermediate NO3 radial produced by NO
2
*
+NO2. The modeling results strongly support the NO
2
*
scheme as the dominant reaction mechanism. 相似文献
15.
[reaction: see text] Chelation between gamma-hydroxybutynenitrile and Grignard reagents triggers a particularly facile anionic conjugate addition reaction. Structurally diverse Grignard reagents add with equal efficiency, providing an intermediate anion that stereoselectively alkylates benzaldehyde in an overall addition-alkylation reaction. 相似文献
16.
Donald G. Fleming Donald J. Arseneau David M. Garner Masayoshi Senba Randall J. Mikula 《Hyperfine Interactions》1984,18(1-4):655-678
The vapor phase fractional polarizations of positive muons thermalizing as the muonium atom (P
M) and in diamagnetic environments (P
D) has been measured in H2O, CH3OH, C6H14, C6H12, CCl4, CHCl3, CH2Cl2 and TMS, in order to compare with the corresponding fractions measured in the condensed phases. There is a marked contrast in every case, with the vapor phase results being largely understandable in terms of a charge exchange/hot atom model. Unlike the situation in the corresponding liquids, there is no permanent lost fraction in the vapor phase in the limit of even moderately high pressures (1 atm); at lower pressures, depolarization is due to hyperfine mixing and is believed to be well understood. For vapor phase CH3OH, C6H14, C6H12, and TMS therelative fractions are found to be pressure dependent, suggesting the importance of termolecular hot atom (or ion) reactions in the slowing down process. For vapor phase H2O and the chloromethanes, the relative fractions are pressure independent. For CCl4,P
M=P
D0.5 in the vapor phase vs.P
D=1.0 in the liquid phase; fast thermal reactions of Mu likely contribute significantly to this difference in the liquid phase. For H2O,P
M 0.9 andP
D0.1 in the vapor phase vs.P
D 0.6 andP
M0.2 in the liquid phase. Water appears to be the one unequivocal case where the basic charge exchange/hot atom model is inappropriate in the condensed phase, suggesting, therefore, that radiation induced spur effects play a major role. 相似文献
17.
Carbonyl 2 + 2 photoaddition occurs selectively to the alkene moiety of 3-(4-methyl-3-pentenoxy)pyridine. Photolysis of alkene containing pyridines in acetophenone gives rise to an oxetane which is obtained with extremely high diastereoselectivity as shown by analysis of the major 2 + 2 photoproduct. A second photoproduct, 2,3-dihydroxy-2,3-diphenylbutane, is obtained as a result of acetophenone coupling. 相似文献
18.
Simultaneous analysis of methionine- and leucine-enkephalin from rat brain: quantification by liquid chromatography-electrochemistry 总被引:1,自引:0,他引:1
This study focuses on the application of liquid chromatography with electrochemical detection (LC-ED) for the analysis of methionine-enkephalin (ME) and leucine-enkephalin (LE) extracted from rat brain regions. The high applied potentials necessary for enkephalin detection required the development of an efficient sample processing protocol. Brain extracts were processed using chromatographic mode sequencing (CMS). The decrease in electroactive interfering substances by CMS improved the chromatographic resolution of ME and LE and the electrode performance. Other qualitative and analytical methods were used to evaluate the enkephalin data obtained by LC-ED for rat brain regions. This study demonstrates that LC-ED provides both the sensitivity and specificity necessary for the analysis of enkephalins from rat brain regions. 相似文献
19.
The thermodynamic functions Gibbs energy, enthalpy and entropy of solution, mixing and solvation of acetaminophen in propylene
glycol (PG) + ethanol (EtOH) cosolvent mixtures were evaluated from solubility data measured at several temperatures, using
the van't Hoff and Gibbs equations. The solubility was greater at 50% m/m of PG at 20.0^C, while it was greater at 80% of
PG at 40.0 ^C where m/m refers to mass percent. The solvation of this drug is appreciably greater in the mixtures than in
the pure solvents. By means of an enthalpy–entropy compensation analysis, complex behavior was found for the solution. From
0 up to 20% of PG and from 60 up to 100% of PG the solution process is enthalpy driven, whereas from 20 up to 60% of PG it
is entropy driven. These facts can be explained in terms of a decrease in the energy required for cavity formation in the
solvent for mixtures containing 20–60% of PG. 相似文献
20.
The MSR (muonium spin rotation) technique was used to measure the chemical reaction rate for Mu + F2 → MuF + F in N2 moderator at ≈ 1 atm from 295 to 383 K giving the Arrhenius expression: log10k (?/mole s) = (10.83 ± 0.20) - (200 ± 50)/T, with k = (1.46 ± 0.11) × 1010 ?/mole s at 300 K. This is at least 6.8 times the room temperature rate constant for the analogous H atom reaction. The measured activation energy and enhancement over the H reaction rate are indicative of significant tunnelling in the Mu reaction, in agreement with the recent collinear quantum mechanical calculations of Connor et al. 相似文献