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排序方式: 共有578条查询结果,搜索用时 250 毫秒
521.
S.K. Rakshit Y.P. Naik S.C. Parida Smruti Dash Ziley Singh B.K. Sen V. Venugopal 《Journal of solid state chemistry》2008,181(6):1402-1412
Three ternary oxides LiAl5O8(s), LiAlO2(s) and Li5AlO4(s) in the system Li-Al-O were prepared by solid-state reaction route and characterized by X-ray powder diffraction method. Equilibrium partial pressure of CO2(g) over the three-phase mixtures {LiAl5O8(s)+Li2CO3(s)+5Al2O3(s)}, {LiAl5O8(s)+5LiAlO2(s)+2Li2CO3(s)} and {LiAlO2(s)+Li5AlO4(s)+2Li2CO3(s)} were measured using Knudsen effusion quadrupole mass spectrometry (KEQMS). Solid-state galvanic cell technique based on calcium fluoride electrolyte was used to determine the standard molar Gibbs energies of formations of these aluminates. The standard molar Gibbs energies of formation of these three aluminates calculated from KEQMS and galvanic cell measurements were in good agreement. Heat capacities of individual ternary oxides were measured from 127 to 868 K using differential scanning calorimetry. Thermodynamic tables representing the values of ΔfH0(298.15 K), S0(298.15 K) S0(T), Cp0(T), H0(T), {H0(T)-H0(298.15 K)}, G0(T), ΔfH0(T), ΔfG0(T) and free energy function (fef) were constructed using second law analysis and FACTSAGE thermo-chemical database software. 相似文献
522.
Dielectric response of methyl isobutyl ketone (MIBK) in apolar solvents: solute-solvent interactions
Dielectric constants of binary mixtures of MIBK, an extractant used in nuclear energy industry, with six apolar solvents i.e. benzene, dioxane, cyclohexane, carbon tetrachloride, p-xylene and n-heptane have been measured at 455 kHz. The data are used
to evaluate the Eyring’s structural parameter, G*, in these systems to assess the nature of non-specific solute-solvent interaction. The value of G* is found to be influenced by the nature of the solvent. 相似文献
523.
Choi SK Olsen SL Adachi I Aihara H Aulchenko V Aushev T Aziz T Bakich AM Balagura V Bedny I Bitenc U Bondar A Bozek A Bracko M Brodzicka J Browder TE Chang P Chao Y Chen A Chen KF Chen WT Cheon BG Chistov R Choi Y Dalseno J Danilov M Dash M Eidelman S Gabyshev N Golob B Haba J Hara T Hayasaka K Hayashii H Hazumi M Heffernan D Hoshi Y Hou WS Hyun HJ Iijima T Inami K Ishikawa A Ishino H Itoh R Iwasaki M Iwasaki Y Kah DH Kang JH Katayama N Kawai H Kawasaki T Kichimi H Kim HO Kim SK Kim YJ 《Physical review letters》2008,100(14):142001
A distinct peak is observed in the pi +/- psi' invariant mass distribution near 4.43 GeV in B-->K pi +/- psi' decays. A fit using a Breit-Wigner resonance shape yields a peak mass and width of M=4433+/-4(stat)+/-2(syst) MeV and Gamma=45-13+18(stat)-13+30(syst) MeV. The product branching fraction is determined to be B(B 0-->K -/+Z+/-(4430)) x B(Z+/-(4430)-->pi+/-psi')=(4.1+/-1.0(stat)+/-1.4(syst)) x 10(-5), where Z+/-(4430) is used to denote the observed structure. The statistical significance of the observed peak is 6.5 sigma. These results are obtained from a 605 fb(-1) data sample that contains 657 x 10(6) BB pairs collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider. 相似文献
524.
Iwabuchi M Nakao M Adachi I Arinstein K Aulchenko V Aushev T Bakich AM Balagura V Barberio E Bay A Belous K Bhardwaj V Bitenc U Bozek A Bracko M Browder TE Chen A Chen WT Cheon BG Cho IS Choi Y Dalseno J Dash M Drutskoy A Eidelman S Fujikawa M Gabyshev N Ha H Haba J Hayasaka K Hazumi M Heffernan D Horii Y Hoshi Y Hou WS Hyun HJ Inami K Ishikawa A Ishino H Itoh R Iwasaki M Kah DH Kaji H Kang JH Kawai H Kawasaki T Kichimi H Kim HJ Kim HO Kim YI Kim YJ Kinoshita K Korpar S Krizan P Krokovny P 《Physical review letters》2008,101(4):041601
We report on a search for the doubly Cabibbo suppressed decay B+-->D*+pi0, based on a data sample of 657x10(6) BB pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find no significant signal and set an upper limit of B(B+-->D*+pi0)<3.6x10(-6) at the 90% confidence level. This limit can be used to constrain the ratio between suppressed and favored B-->D*pi decay amplitudes, r<0.051, at the 90% confidence level. 相似文献
525.
Ushiroda Y Sumisawa K Taniguchi N Adachi I Aihara H Arinstein K Aushev T Bahinipati S Bakich AM Balagura V Barberio E Belous K Bitenc U Bondar A Bozek A Bracko M Browder TE Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Cho IS Choi Y Dalseno J Dash M Eidelman S Epifanov D Gabyshev N Golob B Ha H Haba J Hara K Hara T Hayasaka K Hazumi M Heffernan D Hokuue T Hoshi Y Hou WS Hyun HJ Inami K Ishikawa A Ishino H Itoh R Iwasaki Y Kah DH Kang JH Kawai H Kawasaki T Kichimi H Kim YJ Kinoshita K 《Physical review letters》2008,100(2):021602
We report the first measurement of CP-violation parameters in B0-->rho0gamma decays based on a data sample of 657x10(6)BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the time-dependent and direct CP-violating parameters, Srho0gamma=-0.83+/-0.65(stat)+/-0.18(syst) and Arho0gamma=-0.44+/-0.49(stat)+/-0.14(syst), respectively. 相似文献
526.
Nakahama Y Sumisawa K Adachi I Aihara H Aushev T Bakich AM Balagura V Barberio E Bedny I Belous K Bitenc U Bondar A Bozek A Bracko M Browder TE Chang P Chao Y Chen A Chen KF Chen WT Cheon BG Chistov R Cho IS Choi Y Dalseno J Dash M Drutskoy A Eidelman S Gabyshev N Golob B Ha H Haba J Hara K Hara T Hayasaka K Hazumi M Heffernan D Hoshi Y Hsiung YB Hyun HJ Iijima T Inami K Ishikawa A Ishino H Itoh R Iwasaki M Iwasaki Y Kah DH Kaji H Kang JH Katayama N Kawai H Kawasaki T Kichimi H Kim HJ Kim HO 《Physical review letters》2008,100(12):121601
We report a measurement of the CP-violating parameters in B;{0}-->K_{S}{0}K_{S}{0} decays based on a data sample of 657x10{6} BB[over ] pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e;{+}e{-} collider. In this Letter, one neutral B meson is fully reconstructed in the B;{0}-->K_{S}{0}K_{S}{0} decay mode, and the flavor of the accompanying B meson is identified by its decay products. The CP-violating parameters are measured from the asymmetry in the distributions of the proper-time interval between the two B decays: S_K_{S}{0}K_{S}{0}}=-0.38_{-0.77}{+0.69}(stat)+/-0.09(syst) and A_{K_{S}{0}K_{S}{0}}=-0.38+/-0.38(stat)+/-0.05(syst). 相似文献
527.
Laser material processing involving welding, ablation and cutting involves interaction of intense laser pulses of nanosecond
duration with a condensed phase. Such interaction involving high brightness radiative flux causes multitude of non-linear
events involving thermal phase transition at soild-liquid-gas interfaces. A theoretical perspective involving thermal dynamics
of the vaporization process and consequent non-linear multiple thermal phase transitions under the action of laser plasma
is the subject matter of the present work. The computational calculations were carried out where titanium (Ti) was treated
as a condensed medium. The solution to the partial differential equations governing the thermal dynamics and the underlying
phase transition event in the multiphase system is based on non-stationary Eulerian variables. The Mach number M depicts significant fluctuations due to thermal instabilities associated with the laser beam flux and intensity. A conclusive
amalgamation has been established which relates material surface temperature profile to laser intensity, laser flux and the
pressure in the plasma cloud.
相似文献
528.
Manish Debnath Khushnood Fatma Jyotirmayee Dash 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(10):2968-2983
DNA sequences rich in cytosine have the propensity, under acidic pH, to fold into four‐stranded intercalated DNA structures called i‐motifs. Recent studies have provided significant breakthroughs that demonstrate how chemists can manipulate these structures for nanobiotechnology and therapeutics. The first section of this Minireview discusses the development of advanced functional nanostructures by synthetic conjugation of i‐motifs with organic scaffolds and metal nanoparticles and their role in therapeutics. The second section highlights the therapeutic targeting of i‐motifs with chemical scaffolds and their significance in biology. For this, first we shed light on the long‐lasting debate regarding the stability of i‐motifs under physiological conditions. Next, we present a comparative analysis of recently reported small molecules for specifically targeting i‐motifs over other abundant DNA structures and modulating their function in cellular systems. These advances provide new insights into i‐motif‐targeted regulation of gene expression, telomere maintenance, and therapeutic applications. 相似文献
529.
Khan FA Dash J Sudheer Ch Sahu N Parasuraman K 《The Journal of organic chemistry》2005,70(19):7565-7577
[structures: see text] A stereoselective strategy for the replacement of the 1,2-dihaloalkene bridge of tetrahalonorbornyl derivatives by an oxygen bridge involving stepwise controlled oxidation, cleavage of the dione thus formed, and reiterative intramolecular S(N)2 displacement of two bridgehead halogens is devised. The synthesis of four highly strained pentacyclic bis-oxa-bridged derivatives 10, 27, 28, and 29 with interesting structural variations is presented. The two oxa bridges are syn to each other, separated by central cyclohexane and cycloheptane rings in 10 and 27, while they are anti to each other and are separated by central cyclopentane and furan rings in 28 and 29. In the case of the highly symmetric bis-oxa-bridged derivative 10 the two syn oxa bridges constrain the central cyclohexane ring into the boat form. The endo,anti,endo 2:1 bis adducts of 1,2,3,4-tetrahalo-5,5-dimethoxycyclopenta-1,3-diene with cyclopentadiene were prepared for the first time, while the reactivites of previously unexplored bis adducts derived from furan and cycloheptatriene were revealed. 相似文献
530.
The base hydrolysis of (αβS) (salicylato) (tetraethylenepentamine)cobalt(III) has been investigated in MeOH + water and DMSO + water media (0–70% (v/v) cosolvents) at 20.0 ? t°C ? 35.0 and I = 0.10 mol dm?3 (ClO4?). The phenoxide species [(tetren)CoO2CC6H4O]+ undergoes both OH?-independent and OH?-catalyzed hydrolysis via SN1ICB and SN1CB mechanism, respectively. The OH?-independent hydrolysis of the phenoxide species is catalyzed by both DMSO + water and MeOH + water media, the former exerting a much stronger rate accelerating effect than the latter. The OH?-catalyzed reaction is strongly accelerated by DMSO + water medium but insensitive to the composition of MeOH + water medium up to 40% (v/v) MeOH beyond which it was not detectable under the experimental conditions. Data analysis has been attempted on the basis of the solvent stabilizing and destabilizing effects on the initial state and transition state of the concerned reactions. The nonlinear variation of the activation parameters, ΔH≠ and ΔS≠, with solvent compositions presumably indicates that the solvent structural effects mediate the energetics of solvation of the initial state and transition state of the concerned reactions. The linearity in ΔH≠ vs. ΔS≠ plot accomodating all data for k1 and k2 paths in DMSO + water and MeOH + water further suggests that the solvent effects on these parameters are mutually compensatory. 相似文献