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41.
四氟乙烯和全氟4-甲基-3,6-二氧杂-△~7辛基磺酰氟在溶剂氟里昂-113(F-113)中进行自由基引发聚合反应时,共聚物(T-O)是否有链转移,可以通过测定所得共聚物中的含氯量来得以证实。我们首次应用质子X萤光分析法(PIXE)进行分析。结果表明,共聚物中含氯量小于1ppm,F-113溶剂并未发生链转移。同时,我们测定了已证明有F-113参与链转移反应的F_(40)试样,含氯量高达700ppm。 相似文献
42.
我们利用Born-Mayer-Huggins相互作用势函数对(KF)N(N=108,256,500和864)团簇进行了分子动力学(MD)模拟。为了避免周期性边界条件对相变、成核和重结晶的干扰作用,对体系采用了自由边界。基于MD模拟结果,对团簇的熔化温度、熔化焓、扩散系数、成核速率、固液界面自由能、临界核大小等进行了计算和讨论。在对(KF)864双晶团簇的热退火模拟中,观察到了固态的重结晶和晶粒的生长。经典的成核理论成功地解释了(KF)864双晶团簇的重结晶MD模拟结果。 相似文献
43.
4,4-Difluoro-5-trifluoromethyl-2-(2,2,2-trifluoro-1-trifluoromethylethyl)-4H-1,3-dioxine andcis/trans-3-dimethylamino-2-trifluoromethacryloyl fluoride were obtained by reaction ofN-(3,3,3-trifluoro-2-trifluoromethylprop-1-enyl)dimethylamine with MgSO4·7H2O.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1069–1071, May, 1997. 相似文献
44.
W. Michael Seganish 《Tetrahedron》2005,61(8):2117-2121
This report describes the fluoride-mediated homocoupling of aryl iodides and bromides catalyzed by palladium(0). This coupling protocol is tolerant of electron-donating and electron-withdrawing substitutents on the aryl halide, as well as ortho substitution. Optimum reaction conditions entail 10 mol% Pd(dba)2, 3 equiv of tetrabutyl ammonium fluoride (TBAF) in DMF at 90 °C. 相似文献
45.
Chris J. Adams Michael I. Bruce Brian W. Skelton Allan H. White 《Journal of Cluster Science》1994,5(3):419-441
The reactions between Ru5(
5-C2PPh2)(gm-PPh2(CO)13 (1) and cyclopentadienes afforded the hexanuclear clusters Ru6(
6-C)(
3-PPh2)2(CO)10(-C5
R
5) [R
5 = H5 (2), H4Me (3), Me5 (4)] which contain an encapsulated carbide and a face-capping
3-CH group, formed by cleavage of CC and CP bonds of the C2PPh2 moiety in1. In the reaction with cyclopentadiene, the unusual ligand C13H12O, formed by combination of C2, CO and two molecules of C5H6 (or one molecule of dicyclopentadien), was characterized in the complex Ru5(
4-PPh) (
4-C13H12O)(-PPh2(CO)11(-C5H5) (5). In the reaction with pentamethylcyclopentadiene, the vinylidene complex Ru5(
3-CCHPh)(
4-PPh)(
4-PPh) (-PPh2)(CO)9(-C5Me5) (6) was also formed. 相似文献
46.
The structure, stability, and paths of formation of 11 (HF)m(DMF)n heterocomplexes (m = 1–4, n = 1, 2) were studied in terms of the B3LYP/6-31++G(d, p) density functional calculation. The results of this calculation suggest that: a) addition of hydrogen fluoride molecules to the (HF)mDMF cyclic fragment is the basic tendency in complex formation in the HF-DMF system; b) data about the structure and properties of stable molecular forms that prevail in N,N-dimethylformamide solutions of hydrogen fluoride can be obtained by quantum chemical calculations for (HF)mDMF complexes (m = 5–10). 相似文献
47.
K. V. Titova O. A. D'yachenko V. V. Gritsenko G. V. Shilov 《Russian Chemical Bulletin》1993,42(1):30-35
Potassium fluoride peroxosolvate KF-H2O2 was obtained upon action of a 30% aqueous solution of hydrogen peroxide on solid potassium fluoride dihydrate. As compared to other peroxosolvates, KF-H2O2 is characterized by the highest thermal stability: the decomposition rate constantk
1, at 120°C is 1.4 10–3 min–1, the enthalpy of H2O2 addition to KF is 8.1 kcal/ mol. The correlation between the high stability of KF-H2O2 and the absence of catalytic properties of KF towards H2O2, and the formation of strong intermolecular O-H...F and intramolecular O-H...O hydrogen bonds in the crystal is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 38–44, January, 1993. 相似文献
48.
Electrophysical properties of single crystals of nonstoichiometric phases R1 − y
M
y
F3 − y
, where R = La-Lu, M = Ca, Sr, or Ba, with the tysonite (LaF3) structure, which are present in a metastable state after being grown and cooled, are measured in the temperature interval
extending from 300 to 1073 K. It is discovered that, during a sufficiently long high-temperature investigation, solid solutions
R1 − y
Ca
y
F3 − y
, where R = Tb, Dy, or Ho, undergo irreversible variations in the phase composition in the temperature region 723 to 823 K.
This level of temperatures, which correspond to partial decomposition of phases R1 − y
Ca
y
F3 − y
with the rare-earth elements of the end of the period, lies above the temperatures to which the fluoride solid electrolytes
are usually heated when used in solid-state electrochemical devices. The temperature and concentration dependences of the
phases’ electroconduction are explained in the framework of the vacancy mechanism of anionic transport.
Original Russian Text ? N.I. Sorokin, B.P. Sobolev, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 4, pp. 420–431.
The paper is dedicated to the memory of Prof. M.W. Breiter, formerly of the Vienna Technical University, Austria. 相似文献
49.
The gradient pathways of the reactions of nucleophilic addition of H2O and HF molecules to formaldehyde in the gas phase and in the XH…H2CO…HC(O)OH complex (X=OH, F) were calculated by theab initio RHF/6-31G**, MP2(fc)/6-31G**, and MP2(full)/6-311++G** methods. Both reactions proceed concertedly. The formation of H-bonded bimolecular pre-reaction complexes is the initial
stage of the gas-phase reactions; at the same time, no indications of the formation of stable π-complexes were found on the
potential energy surfaces of systems under study. The calculated energy barriers to the gasphase reactions exceed 40 kcal
mol−1, while those to reactions in the complex XH…H2CO…HC(O)OH (X=OH, F) become more than halved.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2146–2154, November, 1998. 相似文献
50.
Ba7Fe6F32 · 2H2O was prepared from HF aqueous solution in a teflon bomb (Berghof) at 180°C. A partial exchange F?/OH? can be realized in more diluted HF medium and leads to Ba7Fe6F32–x(OH)x · 2H2O. The compounds crystallize in the monoclinic system, space group C2/m (Z = 2) with a = 17.023(1) Å, b = 11.482(1) Å, c = 7.624(1) Å, β = 101.13(1)° for x = 0 and a = 17.036(2) Å, b = 11.489(1) Å, c = 7.620(2) Å, β = 101.48(1)° for x ≈? 5.3. The structures were determined from 2 256 and 1 343 independent reflections for x = 0 and x ≈? 5.3 respectively, collected with a Siemens AED2 four-circle diffractometer with the MoKα radiation (R = 0.0235 and Rw = 0.0240 for x = 0 and R = 0.0324 and Rw = 0.0335 for x ≈? 5.3). The structure, closely related to that of the Jarlite-type, is built up from isolated octahedra trimers [Fe3F16]7?, connected together by Ba2+-cations. The location of anions and water molecules is discussed from bond valence calculations. Magnetic and Mössbauer studies are reported and discussed. 相似文献