全文获取类型
收费全文 | 240篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
化学 | 147篇 |
力学 | 1篇 |
数学 | 44篇 |
物理学 | 65篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 25篇 |
2012年 | 8篇 |
2011年 | 22篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 21篇 |
2007年 | 20篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 5篇 |
1982年 | 2篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有257条查询结果,搜索用时 125 毫秒
81.
82.
83.
Dipl.‐Chem. Matthias Peter Dr. Jose Manuel Flores Camacho Dr. Serguey Adamovski Dr. Luis K. Ono Dipl.‐Chem. Karl‐Heinz Dostert Dr. Casey P. O'Brien Prof. Dr. Beatriz Roldan Cuenya Dr. Swetlana Schauermann Prof. Dr. Hans‐Joachim Freund 《Angewandte Chemie (International ed. in English)》2013,52(19):5175-5179
84.
A. Camacho 《General Relativity and Gravitation》2001,33(5):901-911
In this work we obtain a family of quantum nondemolition variables for the case of a particle moving in an inhomogeneous gravitational field. Afterwards, we calculate the corresponding propagator, and deduce the probabilities associated with the possible measurement outputs. The comparison, with the case in which the position is being monitored, will allow us to find the differences with respect to the case of a quantum demolition measuring process. 相似文献
85.
J. J. Camacho M. Santos L. Díaz L. J. Juan J. M. L. Poyato 《Applied Physics A: Materials Science & Processing》2010,99(1):159-175
A spectroscopic study of ambient air plasma, initially at room temperature and pressures ranging from 32 to 101 kPa, produced
by high-power transverse excitation atmospheric (TEA) CO2 laser (λ=9.621 and 10.591 μm; τ
FWHM≈64 ns; power densities ranging from 0.29 to 6.31 GW cm−2) has been carried out in an attempt to clarify the processes involved in laser-induced breakdown (LIB) air plasma. The strong
emission observed in the plasma region is mainly due to electronic relaxation of excited N, O and ionic fragments N+. The medium-weak emission is due to excited species O+, N2+, O2+, C, C+, C2+, H, Ar and molecular band systems of N
2+(_{2}^{+}(
B
2\varSigma u+^{2}\varSigma _{\mathrm{u}}^{+}
–X
2\varSigma g+)^{2}\varSigma _{\mathrm{g}}^{+})
, N2(C3
Π
u–B3
Π
g), N
2+(_{2}^{+}(
D2
Π
g–A2
Π
u) and OH(A2
Σ
+–X2
Π). Excitation temperatures of 23400±700 K and 26600±1400 K were estimated by means of N+ and O+ ionic lines, respectively. Electron number densities of the order of (0.5–2.4)×1017 cm−3 and (0.6–7.5)×1017 cm−3 were deduced from the Stark broadening of several ionic N+ and O+ lines, respectively. Estimates of vibrational and rotational temperatures of N
2+_{2}^{+}
electronically excited species are reported. The characteristics of the spectral emission intensities from different species
have been investigated as functions of the air pressure and laser irradiance. Optical breakdown threshold intensities in air
at 10.591 μm have been measured. 相似文献
86.
M. Santos L. Díaz J. J. Camacho J. M. L. Poyato J. Pola T. Krenek 《Applied Physics A: Materials Science & Processing》2010,99(4):811-821
Laser-induced breakdown spectroscopy (LIBS) in germane (GeH4), initially at room temperature and pressures ranging from 2 to 10 kPa, was studied using a high-power transverse excitation
atmospheric (TEA) CO2 laser (λ=10.653 μm, τ
FWHM=64 ns and power densities ranging from 0.28 to 5.52 GW cm−2). The strong emission spectrum of the generated plasma is mainly due to electronic relaxation of excited Ge, H and ionic
fragments Ge+, Ge2+ and Ge3+. The weak emission is due to molecular bands of H2. Excitation temperatures of 8100±300 K and 23,500±2500 K were estimated by Ge atomic and Ge+ singly ionized lines, respectively. Electron number densities of the order of (0.7–6.2)×1017 cm−3 were deduced from the Stark broadening of several atomic Ge lines. The characteristics of the spectral emission intensities
from different species have been investigated as functions of the germane pressure and laser irradiance. Optical breakdown
threshold intensities in germane at 10.653 μm have been determined. The mechanism of initiation of the laser-induced plasma
in germane has been analyzed. 相似文献
87.
A C Camacho Rodrigues J L Fontes Monteiro 《Journal of Thermal Analysis and Calorimetry》2006,83(2):451-455
The effect of the calcination procedure on the decomposition
of the [Pt(NH3)4]2+
complex in a NaX zeolite was studied by mass spectrometry (MS-TPDE) and diffuse
reflectance spectroscopy (DRS). The decomposition of the complex took place
in two steps. In the first step, under oxygen, the [Pt(NH3)4]2+
complex was first converted to [Pt(NH3)2]2+
complex, accompanied by nitrogen release. In the second step, corresponding
to the decomposition of the remaining two amine ligands, NO formation was
also observed. Under He, the decomposition also occurred in two steps with
H2 liberation. A reaction scheme was proposed for these
results. 相似文献
88.
Pérez-Morales M Muñoz E Martín-Romero MT Camacho L 《Langmuir : the ACS journal of surfaces and colloids》2005,21(12):5468-5474
The oxidative electrodeposition of NiTSPP (tetrakis(4-sulfonatophenyl) Ni porphyrin) on ITO electrode from 0.1 M NaOH aqueous solution has been studied, and UV-visible and reflection FTIR spectroscopies have been used to analyze the composition of such film. By use of UV-vis spectroscopy, small absorbance of the film and an almost nulling effect on the Soret band of the porphyrin along the Ni(III)/Ni(II) redox process were observed. The reflection FTIR spectroscopy detected the presence of Ni-OH groups in the reduced film and as well the state of the porphyrin molecules as radical cation. Moreover, the porphyrin has been quantified by means of the area of the vibration bands assigned to the sulfonate groups by using as reference a Langmuir-Blodgett film containing a known surface concentration of NiTSPP. These results lead us propose the formation of a conductor salt by electrocrystallization, with stoichiometries TSPP/Ni(II)(OH)2 and TSPP/Ni(III)OOH, for its reduced and oxidized forms, respectively. In these two forms, the porphyrin rings will be present as radical cation, which may be stabilized through its dimerization or polymerization. 相似文献
89.