全文获取类型
收费全文 | 520篇 |
免费 | 10篇 |
国内免费 | 2篇 |
专业分类
化学 | 364篇 |
晶体学 | 9篇 |
力学 | 2篇 |
数学 | 24篇 |
物理学 | 133篇 |
出版年
2020年 | 4篇 |
2018年 | 5篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 29篇 |
2012年 | 36篇 |
2011年 | 39篇 |
2010年 | 17篇 |
2009年 | 14篇 |
2008年 | 39篇 |
2007年 | 45篇 |
2006年 | 32篇 |
2005年 | 35篇 |
2004年 | 21篇 |
2003年 | 18篇 |
2002年 | 18篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有532条查询结果,搜索用时 15 毫秒
461.
A newly constructed sensitive microwave cavity spectrometer of the Stark-dc-voltage sweep type has revealed that formaldehyde in concentrations as small as 0.2 ppm can be directly detected by using the 725 ← 726 rotational line. The cavity resonator is operated in the rectangular TE1,0,20 mode. A sample of automobile-engine exhaust showed a strong spectrum indicating a concentration of 24 ppm of formaldehyde. 相似文献
462.
Takayuki Mito Shigeru Fujino Hiromichi Takebe Kenji Morinaga Shin-ichi Todoroki Shigeki Sakaguchi 《Journal of Non》1997,210(2-3)
Refractive index dispersion curves in the wavelength region of 0.40 to 5.03 μm are presented for multi-component oxide glass systems: borate, silicate, aluminate, germanate, tellurite, antimonate and heavy metal gallate. The material dispersion was determined using the refractive index data. Reflection spectra in the ultraviolet and infrared regions were measured to investigate the effects of electronic transitions and lattice vibrations on the material dispersion. Thallium tellurite, thallium antimonate and lead gallate glasses exhibit zero material dispersion wavelengths (ZMDWs) over 2.4 μm. The factors affecting the ZMDW are discussed. 相似文献
463.
The electronic structure of doped orthorhombic (La0.6Pr0.4)0.7Ca0.3MnO3 manganite is studied using the second optical harmonic generation method. The analysis of the frequency and polarization dependence of the intensity related to the second harmonic demonstrates that the applied magnetic field stimulates a transition of spin-polarized electrons from the d orbitals of Mn ions to the p orbitals of O2 ligands. The manifestation of such transition in the orthorhombic RMnO3 manganite with the distorted crystal lattice is attributed to the dipole-forbidden electronic transitions arising in the applied magnetic field. The mechanism of magnetooptical activity induced by the charge transfer between Mn and O ions is discussed. 相似文献
464.
We prove two nonlinear ergodic theorems for noncommutative semigroups of nonexpansive mappings in Banach spaces. Using these
results, we obtain some nonlinear ergodic theorems for discrete and one-parameter semigroups of nonexpansive mappings.
Dedicated to Professors Albrecht Dold and Ed Fadell 相似文献
465.
Kenji WADA Yoshihiro MlSHINA Shigenori FUJIWARA Hiromichi HORINAKA Yoshio CHO Tokuo UMEDA 《Optical Review》1999,6(2):93-96
Aiming at the realization of optical CT (computed tomography), the extraction of quasi-straightforward-propagating photons from optical pulses transmitting through a standard scattering medium of Intralipid-10% aqueous solution has been demonstrated by an up-conversion method (second harmonic generation). We have found that this operates as a coherent light detection method rather than a time-gate one and extends the dynamic range where the Lambert-Beer’s law holds to − 86 dB. We have also proposed improvements to obtain the largest possible dynamic range by such an up-conversion technique. 相似文献
466.
Bruno Bellomo Giuseppe Compagno Hiromichi Nakazato Kazuya Yuasa 《Journal of Russian Laser Research》2009,30(5):451-457
The dynamics of a system made of a particle interacting with a field mode “thwarted” by the action of repeated projective
measurements on the particle is examined. The effect of the partial measurements is discussed by comparing it with the dynamics
in the absence of the measurements. 相似文献
467.
Masafumi Takesue Atsuko Suino Hiromichi Hayashi 《Journal of solid state chemistry》2008,181(6):1307-1313
Luminescence appearance of Mn-doped zinc silicate (Zn2SiO4:Mn2+, ZSM) formed in supercritical water at 400 °C and 29 MPa at reaction times from 1 to 4320 min was studied in the relation to its phase formation mechanism. Appearance of luminescent ZSM from green emission by α-ZSM and yellow emission by β-ZSM occurred over the same time period during the onset of phase formation at a reaction time of 2 min. Luminescence appeared at a much lower temperature and at shorter reaction times than the conventional solid-state reaction. Needle-like-shaped α-ZSM was the most stable particle shape and phase in the supercritical water reaction environment and particles formed via two routes: a homogenous nucleation route and a heterogenous route that involves solid-state diffusion and recrystallization. 相似文献
468.
Takashi Yasui Yuki Kashihara Fumiko Miyake Seiko Sugitani Hiromichi Yamada Akio Yuchi 《Analytical sciences》2008,24(8):993-997
The interactions between Cu(II) complexes with heterocyclic azo compounds and several anions were studied by equilibrium analysis of ion-pair extraction, RP-HPLC of metal complexes, and ion chromatography of anions on an ODS column coated with Cu(II) complexes of the long alkyl derivatives. Both ion-pair extraction and HPLC studies demonstrated that a dicationic complex with 8-(3,5-dibromo-2-pyridylazo)-5-aminoquinoline interacted with anions stronger than a monocationic complex with 2-(2-pyridylazo)methylphenol. Anions were more retained on the column coated with dicationic Cu(II) complex. Such differences were quantitatively ascribed to the first ion-pair formation of the dicationic complex giving a monocationic species. 相似文献
469.
The kinetics of CO molecules with excited electronic levels for a nonequilibrium flow in nozzles is studied. Three electronic energy levels are taken into account; the VV exchanges of the vibrational energy within each electronic energy level, VT transitions from the vibrational energy to the translational energy, and VE exchanges between the vibrational energy and the electronic terms occur in the system. The system of equations of vibrational level kinetics and gasdynamics, which is written in the zeroth approximation of the Chapman–Enskog method, is solved numerically. Special attention is paid to estimating the effect of the VE exchanges of the vibrational energy on the formation of nonequilibrium populations of the vibrational levels. It is shown that resonant VE transitions considerably affect the relaxation process and noticeably change the population of the upper vibrational levels even in the absence of recombination and dissociation processes; VE exchanges also affect the time dependence of the vibrational temperature. 相似文献
470.
Takamasa Seta Hiromichi Hoshina Iwao Hosako Stefan Loßow Mattias Ekström Donal Murtagh 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(1):144-150
The air induced broadening coefficients of the pure rotational transitions of H2O at 556.936 GHz (110←101), and 752.033 GHz (211←202) were measured by terahertz time-domain spectroscopy. The air broadening coefficient was determined to be for the 556.936 GHz line and for the 752.033 GHz line, respectively. The present broadening coefficients for the 556.936 GHz water line are significantly smaller than those of Markov and Krupnov [Measurements of the pressure shift of the 1(10)-1(01) water line at 556.936 GHz produced by mixtures of gases. J Mol Spect 1995:172;211-4] but relatively close to the values of the HITRAN database. The measured data may improve the accuracy of the abundance of water vapor retrieved from spectra obtained by the Odin/SMR satellite instrument. The effect on the satellite retrieval processing is discussed. 相似文献