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71.
72.
G. P. Gupta A. Z. Msezane 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):157-160
Excitation energies from ground state for 97 fine-structure levels as well as oscillator strengths and radiative decay rates
for all electric-dipole-allowed and intercombination transitions among the fine-structure levels of the terms belonging to
the (1s
22s
22p
6)3s
23p, 3s
3
p
2, 3s
23d, 3p
3, 3s3p3d, 3p
23d, 3s3d
2, 3s
24s, 3s
24p, 3s
24d, 3s
24f, and 3s3p4s configurations of Co XV are calculated, using extensive configuration-interaction (CI) wave functions, obtained with the
CIV3 computer code of Hibbert. The important relativistic effects in intermediate coupling are included through the Breit-Pauli
approximation via spin-orbit, spin-other-orbit, spin-spin, Darwin and mass correction terms. Small adjustments to the diagonal
elements of the Hamiltonian matrices have been made. Our calculated excitation energies, including their ordering, are in
excellent agreement with the experimental results and the experimentally compiled energy values of the National Institute
for Standards and Technology (NIST) wherever available. The mixing among several fine-structure levels is found to be very
strong, with most of the strongly mixed levels belonging to the (1s
22s
22p
6)3p
23d and 3s3d
2 configurations. The strong mixing among several fine-structure levels makes it very difficult to identify them uniquely.
Perhaps, that may be the reason for the lack of both experimental and theoretical results for these levels. We believe that
our extensive calculated values can guide experimentalists in identifying the fine-structure levels in their future work.
From our radiative decay rates we have also calculated radiative lifetimes of some fine-structure levels. In this calculation
we also predict new data for several fine-structure levels where no other theoretical and/or experimental results are available. 相似文献
73.
P. P. Pershukevich I. K. Shushkevich E. A. Makarova K. N. Solov’eva 《Journal of Applied Spectroscopy》2008,75(5):706-713
We have studied the spectral luminescence properties of a zinc complex of dibenzobarreleno-substituted tetraazaisobacteriochlorin
(a synthetic tetrapyrrole pigment which is the structural analog of the biologically important chromophore isobacteriochlorin)
and a palladium complex of dibenzobarreleno-substituted tetraazachlorin. We have shown that despite the substantial effect
of aza-substitution on the electronic structure and the electronic spectra of the tetrapyrrole molecules, the effect of hydrogenation
of adjacent pyrrole rings on the spectral luminescence properties is similar in compounds with nitrogen and carbon bridges.
As in the free base case, the fluorescence of the studied zinc complex is strongly quenched at 293 K but flares up at 77 K
(temperature and viscosity-dependent quenching). To study the substituted Zn-tetraazaisobacteriochlorin, we determined the
position of the 0-0 band of the low-intensity transition S0 → S2 and showed that the S2 → S1 energy difference increases with bridge aza substitution. For the Pd complex of dibenzobarreleno-substituted tetraazachlorin,
we could not detect phosphorescence in the near IR region (to 1150 nm); we detected weak fluorescence.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 700–707, September–October, 2008. 相似文献
74.
Using first-principle calculations, mechanical properties, electronic structure, and Raman spectra of LiB6Si structure were investigated. The band structures calculated by GGA-PBE and HSE06 methods reveal that LiB6Si is an indirect band gap semiconductor. The band gap estimated by HSE06 method is about 2.24 eV, which is in good agreement with that of experimental value 2.27 eV. The calculated tensile stress-strain curves of LiB6Si reveal that [010] direction is the cleavage direction under tensile strains. The calculated Raman spectra of LiB6Si are also in good agreement with that of measured. The position of the band gap may provide a basis for further photocatalysis research on LiB6Si. 相似文献
75.
Dr. Giovanny Carvalho dos Santos Juan Carlos Roldao Dr. Junqing Shi Dr. Begoña Milián-Medina Prof. Dr. Luiz Carlos da Silva-Filho Dr. Johannes Gierschner 《Chemphyschem》2020,21(16):1797-1804
A combined spectroscopic and TD-DFT case study was performed, to identify a robust method to calculate the complex near UV/Vis absorption spectra of various amino- vs. nitro-substituted 2,4-diphenylquinolines, which vary strongly under neutral and successively acidic conditions. For this, different DFT functionals were tested for geometry optimization and the TD part to calculate the neutral and different protonated species in a fast screening approach, i. e. using single point calculations in an implicit solvent. Offset-corrected M06HF, hitherto only applied to polymers, was identified as a suitable method to reproduce the absorption spectra in a reasonable fashion for all different substitution pattern and all different protonated species at different pH values; moreover, the method properly predicts the energetic ordering of low-lying n-π* and ππ* transitions, which is decisive for the non-/emissive nature of the different compounds. In all, this might provide a valuable tool for computer-aided design of related classes of compounds. 相似文献
76.
O.N Ulenikov O.L Petrunina E.S Bekhtereva E.A Sinitsin H BürgerW Jerzembeck 《Journal of Molecular Spectroscopy》2002,215(1):85-92
For the first time the infrared spectrum of PHD2 was recorded in the region of the PH stretching fundamental ν1 at 2324.005 cm−1 and the overtone 2ν1 at 4563.634 cm−1 with a resolution of 4.2×10−3 cm−1 and 8.8×10−3 cm−1, respectively. In the analyses about 1340 and 1020 transitions were assigned to the corresponding ν1 and 2ν1 bands, which provided 316 and 248 upper energies, respectively. Since both the bands are sufficiently isolated, a standard Watson-type Hamiltonian (A-reduction, Ir-representation) was employed. The obtained sets of spectroscopic parameters correlate very well both with each other, and with the corresponding parameters of the ground vibrational state. 相似文献
77.
文中叙述了HL-1M托卡马克硼化真空紫外光谱区杂质辐射的观测结果。分析得出:硼化有效地控制等离子体中的杂质,其中,氧杂质减少约65%,碳杂质减少约60%,金属杂质减少约85%。 相似文献
78.
利用金刚石压腔结合拉曼光谱分析技术,研究了文石在18~388 ℃,71~2 014 MPa,以及方解石在19~351 ℃,96~1 823 MPa条件下的拉曼光谱特征,并得到文石和方解石的拉曼位移与温度、 压力三者之间的关系式。研究结果表明,文石和方解石的拉曼位移随温度压力的变化规律相似,都随压力升高向高频移动,除文石的704 cm-1外均随温度升高向低频移动。二者的晶格振动νi/T值均大于[CO3]基团内振动的值,说明CaO6八面体的热膨胀性大于[CO3]基团的热膨胀性。二者的对称伸缩振动ν/T及ν/P值不同,由于该振动拉曼位移和C—O键的键长有关,方解石的C—O键的热膨胀性比文石小而可压缩性比文石大。另外升温升压过程中文石和方解石可以相互转化,伴随该过程发生的[CO3]基团旋转变形等动力学因素也可以造成二者νi/T和νi/P值差异。 相似文献
79.
G.M. Koretsky M.B. Knickelbein 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(3):273-278
The photoionization spectra of Pr2-Pr21 and Ce2-Ce17 have been measured near threshold. The ionization potentials (IPs) of and vary discontinuously with size, but trend downward toward the work function of the bulk metals. In general, the IPs of cerium
clusters display more variation than those of praseodymium clusters. The sudden discontinuities observed in the IPs of both
and is akin to that displayed by clusters of transition metal atoms, suggesting that as in transition metal clusters, the rapid
evolution in geometric structure with size is the source of these discontinuities.
Received: 2 January 1998 / Accepted: 10 March 1998 相似文献
80.
刘小珍 《光谱学与光谱分析》1998,18(5):614-616
本文用电感耦合等离子体原子发射光谱法,X射线荧光光谱法、红外光谱以及X射线衍射谱测定了石棉红花岗石和芝麻白花岗石的成分和光谱、根据石棉红岗石和芝麻白花岗石的X射线衍射谱,用计算机检索它们的组成,对计算机检索的结果进行对比得出,石棉红花岗石的红色是由于它含有Fe的红色矿物而产生的。 相似文献