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101.
绿松石的激光拉曼光谱研究 总被引:1,自引:0,他引:1
对湖北、安徽地区绿松石进行了激光拉曼光谱测试分析。结果表明,绿松石中H2O,OH-及PO3-4的基团振动是导致其激光拉曼光谱形成的主要原因。3 510~3 440 cm-1的谱峰是由ν(OH)伸缩振动所致,其中ν(OH)振动导致的强拉曼特征谱峰在3 470 cm-1附近,ν(H2O)伸缩振动致拉曼谱峰位于3 290~3 070 cm-1附近的较为宽缓的弱谱峰处;由ν3(PO4)伸缩振动致强拉曼特征谱峰在1 200~1 030 cm-1之间,其中ν3(PO4)振动导致的强拉曼特征谱峰在1 039 cm-1附近,ν4(PO4)弯曲振动位于650~540 cm-1范围,ν2(PO4)的弯曲振动谱峰位于500~410 cm-1处;不同产地、不同结晶类型的绿松石表现出的拉曼谱峰特征基本一致。 相似文献
102.
For every diffeomorphism φ:M→N between 3-dimensional Riemannian manifolds M and N, there are locally two 2-dimensional distributions D± such that φ is conformal on both of them. We state necessary and sufficient conditions for a distribution to be one of D±. These are algebraic conditions expressed in terms of the self-adjoint and positive definite operator induced from φ∗. We investigate the integrability condition of D+ and D−. We also show that it is possible to choose coordinate systems in which leafwise conformal diffeomorphism is holomorphic on leaves. 相似文献
103.
Pressure-dependent thermodynamic properties of the ambient and high pressure phases of aluminum nitride (w-AlN and rs-AlN) were calculated from first principles in order to determine their phase boundary in the p? T phase diagram. These predictions were checked by static HP/HT experiments, using a multianvil press and an Al/N/H precursor with low decomposition temperature as educt. The experimental data show that at temperatures between 1000 and 2000 K, the boundary line between the two phases is situated between 11 and 12 GPa, which is ~1.3 GPa lower than the theoretical result and generally lower than previously assumed. The hardness of rs-AlN – measured for the first time – is ~30 GPa (Knoop indenter at loads of 25–50 g), twice as hard as w-AlN. Shock wave recovery experiments on nano w-AlN allowed testing of the chemical and thermal stability of rs-AlN, and determination of its infrared absorption and 27Al NMR data. The shock wave technique will eventually enable the synthesis of larger amounts of rs-AlN, making it available for technological use. Finally, implications on the high pressure stability of phases in the Si–Al–O–N system are discussed in the light of thermoelastic properties of AlN. 相似文献
104.
Multiparameter kinetic analysis of alkaline hydrolysis of a series of aryl diphenylphosphinothioates: models for P=S neurotoxins 下载免费PDF全文
Ik‐Hwan Um Jeong‐Yoon Han Young‐Hee Shin Julian M. Dust 《Journal of Physical Organic Chemistry》2017,30(7)
Alkaline hydrolysis of a series of X‐substituted‐phenyl diphenylphosphinothioates ( 2a‐i ) in 80 mol%/20 mol% DMSO at 25.0 ± 0.1°C has been studied kinetically and assessed through a multiparameter approach. Substrates 2a to 2i are approximately 12 to 22 times less reactive than their P=O analogues 1a to 1i (ie, the thio effect). The Brønsted‐type plot for the reactions of 2a to 2i is linear with βlg = ?0.43, consistent with a concerted mechanism. Hammett plots correlated with σo and σ? constants also support a concerted mechanism; the Yukawa‐Tsuno plot results in an excellent linear correlation with ρX = 1.26 and r = 0.30, indicating that expulsion of the leaving group occurs in the rate‐determining step (RDS). The ΔH? value increases from 10.5 to 11.7 and 13.9 kcal/mol as substituent X in the leaving group changes from 3,4‐(NO2)2 to 4‐NO2 and H, in turn, while TΔS? remains constant at ?6.0 kcal/mol. The strong dependence of ΔH? on the electronic nature of substituent X also indicates that the leaving group departs in the RDS. The reaction mechanism and origin of the thio effect are discussed by comparison of the current kinetic results with those reported for the reactions of 1a to 1i . The results suggest that for useful OP neurotoxins the mechanism of abiotic hydrolysis is concerted (with varying degrees of asynchronicity) when the substrate bears good leaving groups. 相似文献
105.
Anilinolysis of O‐butyl phenyl phosphonochloridothioate in acetonitrile: Synthesis,characterization, kinetic study,and reaction mechanism 下载免费PDF全文
This paper describes a simple optimized method for the synthesis of O‐butyl phenyl phosphonochloridothioate ( 4 ) under mild conditions. The target compounds were characterized by 1H‐nuclear magnetic resonance (NMR), 13C‐NMR, and 31P‐NMR spectroscopy, as well as mass spectroscopy. The apparent structure of 4 was confirmed by optimization using the B3LYP/6‐311 + G(d,p) level in the Gaussian 09 program in acetonitrile. The nucleophilic substitution reactions of 4 with X‐anilines (XC6H4NH2) and deuterated X‐anilines (XC6H4ND2) were investigated kinetically in acetonitrile at 55.0°C. The free energy relationship with X in the anilines looked biphasic concave upwards with a break region between X = H and X = 3‐MeO, giving large negative ρX and small positive βX values. The deuterium kinetic isotope effects were secondary inverse (kH/kD < 1: 0.789‐0.995) and the magnitudes, (kH/kD), increased when the nucleophiles were changed from weakly basic to strongly basic anilines. A concerted SN2 mechanism is proposed on the basis of the selectivity parameters and the variation trend of the deuterium kinetic isotope effects with X. 相似文献
106.
《光谱学快报》2013,46(1):145-152
ABSTRACT [CuCl(L-Prolinato)(H2O)] was prepared. Its electronic absorption spectrum and photoacoustic spectrum were recorded at the room temperature. A semi-empirical method of ligand-field-theory PLFT was utilized to calculate the d-d transition energy. According to the results, the spectrum was explained satisfactorily. 相似文献
107.
Yanyun Chu Zhongzhou Ren Chang Xu 《The European Physical Journal A - Hadrons and Nuclei》2008,37(3):361-366
Using a three-body model and realistic two-body potentials, we investigate the properties of the nuclei 18Ne and 28S near the proton dripline. We figure out the two-proton separation energies, occupation of the valence protons, root-mean-square
radii of matter and the valence protons. Besides, the spatial correlation densities are displayed to reflect the correlation
between the two valence protons. The first excited 0+ state of 18Ne is most likely to be a halo state according to our calculation. Turning off the Coulomb interactions among the three-body
systems, we get the two-neutron separation energies and configuration of the valence neutrons of their corresponding mirror
nuclei. The results indicate that the three-body model is proper to describe some proton-rich nuclei and can be used to deduce
reliable information. 相似文献
108.
《Journal of Pure and Applied Algebra》2023,227(5):107271
In this paper, we give a numerical criterion of Reider-type for the d-very ampleness of the adjoint line bundles on quasi-elliptic surfaces, and meanwhile we give a new proof of the vanishing theorem on quasi-elliptic surfaces emailed from Langer and show that it is the optimal version. 相似文献
109.
110.