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161.
Hasegawa N Charra V Inoue S Fukumoto Y Chatani N 《Journal of the American Chemical Society》2011,133(21):8070-8073
The regioselective carbonylation of unactivated C(sp(3))-H bonds of aliphatic amides was achieved using Ru(3)(CO)(12) as a catalyst. The presence of a 2-pyridinylmethylamine moiety in the amide is crucial for a successful reaction. The reaction shows a preference for C-H bonds of methyl groups as opposed to methylene C-H bonds and tolerates a variety of functional groups. The stoichiometric reaction of an amide with Ru(3)(CO)(12) gave a dinuclear ruthenium complex in which the 2-pyridinylmethylamino moiety was coordinated to the ruthenium center in an N,N manner. 相似文献
162.
Inokuchi Y Boyarkin OV Ebata T Rizzo TR 《Physical chemistry chemical physics : PCCP》2012,14(13):4457-4462
We report UV photodissociation (UVPD) and IR-UV double-resonance spectra of 1,2-dimethoxybenzene (DMB) complexes with alkali metal ions, M(+)·DMB (M = Li, Na, K, Rb, and Cs), in a cold, 22-pole ion trap. The UVPD spectrum of the Li(+) complex shows a strong origin band. For the K(+)·DMB, Rb(+)·DMB, and Cs(+)·DMB complexes, the origin band is very weak and low-frequency progressions are much more extensive than that of the Li(+) ion. In the case of the Na(+)·DMB complex, spectral features are similar to those of the K(+), Rb(+), and Cs(+) complexes, but vibronic bands are not resolved. Geometry optimization with density functional theory indicates that the metal ions are bonded to the oxygen atoms in all the M(+)·DMB complexes. For the Li(+) complex in the S(0) state, the Li(+) ion is located in the same plane as the benzene ring, while the Na(+), K(+), Rb(+), and Cs(+) ions are located off the plane. In the S(1) state, the Li(+) complex has a structure similar to that in the S(0) state, providing the strong origin band in the UV spectrum. In contrast, the other complexes show a large structural change in the out-of-plane direction upon S(1)-S(0) excitation, which results in the extensive low-frequency progressions in the UVPD spectra. For the Na(+)·DMB complex, fast charge transfer occurs from Na(+) to DMB after the UV excitation, making the bandwidth of the UVPD spectrum much broader than that of the other complexes and producing the photofragment DMB(+) ion. 相似文献
163.
Shimada D Kusaka R Inokuchi Y Ehara M Ebata T 《Physical chemistry chemical physics : PCCP》2012,14(25):8999-9005
The lifetimes of methyl 4-hydroxycinnamate (OMpCA) and its mono-hydrated complex (OMpCA-H(2)O) in the S(1) state have been measured by picosecond pump-probe spectroscopy in a supersonic beam. For OMpCA, the lifetime of the S(1)-S(0) origin is 8-9 ps. On the other hand, the lifetime of the OMpCA-H(2)O complex at the origin is 930 ps, which is ~100 times longer than that of OMpCA. Furthermore, in the complex the S(1) lifetime shows rapid decrease at an energy of ~200 cm(-1) above the origin and finally becomes as short as 9 ps at ~500 cm(-1). Theoretical calculations with a symmetry-adapted cluster-configuration interaction (SAC-CI) method suggest that the observed lifetime behavior of the two species is described by nonradiative decay dynamics involving trans → cis isomerization. That is both OMpCA and OMpCA-H(2)O in the S(1) state decay due to the trans → cis isomerization, and the large difference of the lifetimes between them is due to the difference of the isomerization potential energy curve. In OMpCA, the trans → cis isomerization occurs smoothly without a barrier on the S(1) surface, while in the OMpCA-H(2)O complex, there exists a barrier along the isomerization coordinate. The calculated barrier height of OMpCA-H(2)O is in good agreement with that observed experimentally. 相似文献
164.
The reaction of terminal alkynes with imines using ReBr(CO)(5) as a catalyst results in the production of N-alkylideneallylamines and not the conventional propargylamines. The substituent on the imine nitrogen is important, and a diphenylmethyl group gave the best result. The catalytic cycle of this regioselective C-C bond forming reaction appears to involve the formation of an alkynyl rhenium species and subsequent nucleophilic attack of the alkynyl β-carbon atom on the imine carbon to give a vinylidene rhenium species. 相似文献
165.
H. Amemiya 《Annalen der Physik》1985,497(3):293-306
The Result of Measurements of the energy distribution of thermal electrons in a midlatitude ionosphere is presented. A comparison is made in particular between the characteristics at sunrise and sunset periods because of the effect of vibrationally excited nitrogen molecules. At sunrise the distribution has a little-irregularity but the middle and higher energy parts (0.2-0.5 eV) deviate from the Maxwellian distribution only slightly at all heights. The electron temperature varies from 900 K to 1300 K between 130 km and 300 km. These values are higher than the kinetic temperature of neutral particles but comparable with the theoretical values of the vibration temperature of N2. At sunset small bumps due to non-thermal electrons are seen on the high energy tail between 108 and 160 km, their density being from 5 × 10?3 to 1 × 10?2 of that one of the thermal electrons. Above 170 km (F-layer) the deviation of the distribution from the Maxwellian one becomes smaller. The electron temperature varies from 500 K to 900 K between 100 km and 220 km. These values are higher than the kinetic temperature but lower than the theoretical values of the vibration temperature of N2. A mechanism of the appearance of non-thermal electrons is considered to be due to super-elastic collisions with vibrationally excited N2. 相似文献
166.
167.
Hiroshi Amemiya 《Physics letters. A》1977,62(4):220-222
The suppression of naturally excited waves by an externally applied wave in the travelling wave type of beam-plasma interaction is shown to be due to a wave perturbation on the beam distribution function experimentally. 相似文献
168.
169.
170.
Reaction-path switching induced by spatial-distribution change of reactants: CO oxidation on Pt(111)
Nakai I Kondoh H Amemiya K Nagasaka M Nambu A Shimada T Ohta T 《The Journal of chemical physics》2004,121(11):5035-5038
We studied the mechanism of CO oxidation on O-covered Pt(111) surfaces during CO exposure by means of time-resolved near edge x-ray absorption fine structure spectroscopy. Two distinct reaction processes were found to occur sequentially; isolated O atoms and island-periphery O atoms contribute to each process. Combination of in situ monitoring of the reaction kinetics and Monte Carlo simulations revealed that CO coadsorption plays a role of inducing the dynamic change in spatial distribution of O atoms, which switches over the two reaction paths. 相似文献