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131.
Edward Mikuli Marta Liszka-Skoczylas Joanna Hetmańczyk Janusz Szklarzewicz 《Journal of Thermal Analysis and Calorimetry》2010,102(3):889-897
[Mn(NH3)6](NO3)2 crystallizes in the cubic, fluorite (C1) type crystal lattice structure (Fm \( \overline{3} \) m) with a = 11.0056 Å and Z = 4. Two phase transitions of the first-order type were detected. The first registered on DSC curves as a large anomaly at T C1 h = 207.8 K and T C1 c = 207.2 K, and the second registered as a smaller anomaly at T C2 h = 184.4 K and T C2 c = 160.8 K (where the upper indexes h and c denote heating and cooling of the sample, respectively). The temperature dependence of the full width at half maximum of the band associated with the δs(HNH)F1u mode suggests that the NH3 ligands in the high temperature and intermediate phase reorientate quickly with correlation times in the order of several picoseconds and with activation energy of 9.9 kJ mol?1. In the phase transition at T C2 c probably only a some of the NH3 ligands stop their reorientation, while the remainders continue to reorientate quickly with activation energy of 7.7 kJ mol?1. Thermal decomposition of the investigated compound starts at 305 K and continues up to 525 K in four main stages (I–IV). In stage I, 2/6 of all NH3 ligands were seceded. Stages II and III are connected with an abruption of the next 2/6 and 1/6 of total NH3, respectively, and [Mn(NH3)](NO3)2 is formed. The last molecule of NH3 per formula unit is freed at stage IV together with the simultaneous thermal decomposition of the resulting Mn(NO3)2 leading to the formation of gaseous products (O2, H2O, N2 and nitrogen oxides) and solid MnO2. 相似文献
132.
Massoud Kaykhaii Greg W. Dicinoski Rebecca Smedley Janusz Pawliszyn Paul R. Haddad 《Journal of chromatography. A》2010,1217(20):3452-3456
The use of a functionalized latex nanoparticle coating as a new sorbent phase for solid-phase microextraction (SPME) was examined. By means of electrostatic absorption onto ionized silanol groups, a fused-silica rod was coated with polymeric nanoparticles functionalized with quaternary ammonium groups. Optimum conditions for the preparation of the coated fibre are presented. The fibre was used for the extraction of a mixture of seven anions from water samples which are analysed by coupling the SPME fibre to an ion chromatographic system via a special interface. The results obtained proved the suitability of this novel coating as a new SPME fibre. A linear calibration for the target analytes was achieved over the concentration range from 5 μg L−1 to 5 mg L−1 (r2 > 0.988), while limits of detection for these ions were all below 3.7 μg L−1 (S/N = 3). The reproducibility of a single fibre (n = 4) under similar conditions was between 7 and 12%, while the fibre to fibre reproducibility (n = 5) was between 8.9 and 14%. 相似文献
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135.
Anna Jaśkiewicz Janusz Matkowski Andrzej S. Nowak 《Annals of Operations Research》2014,220(1):263-278
This paper generalizes the classical discounted utility model introduced in Samuelson (Rev. Econ. Stud. 4:155–161, 1937) by replacing a constant discount rate with a function. The existence of recursive utilities and their constructions are based on Matkowski’s extension of the Banach Contraction Principle. The derived utilities go beyond the class of recursive utilities studied in the literature and enable a discussion on subtle issues concerning time preferences in the theory of finance, economics or psychology. Moreover, our main results are applied to the theory of optimal economic growth related with resource extraction models with unbounded utility function of consumption. 相似文献
136.
Janusz Matkowski 《Periodica Mathematica Hungarica》2014,68(2):119-127
Let \(f\) be a real differentiable function in an open interval \(I\) with one-to-one derivative. We observe that if the Lagrange mean \(L^{[f]}\) of a generator \(f\) is conditionally positively homogeneous, then \(f\) must be of the class \(C^{\infty }\) and the function $$\begin{aligned} g(x):=xf^{\prime }\left( x\right) -f\left( x\right) ,\quad \quad x\in I, \end{aligned}$$ is also a generator of \(L^{[f]}\) i.e. that \(L^{[g]}=L^{[f]}.\) We show that this fact and a result on equality of two Lagrange means allow easily to determine all positively homogeneous Lagrange means. 相似文献
137.
Janusz Zachara Izabela D. Madura Andrzej Zimniak Irena Oszczapowicz Iwona Chrobak 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(11):o625-o627
The structural analysis of deacetylcephalothin [systematic name: (6R,7R)‐3‐hydroxymethyl‐8‐oxo‐7‐(2‐thiophen‐2‐ylacetylamino)‐5‐thia‐1‐azabicyclo[4.2.0]oct‐2‐ene‐2‐carboxylic acid], C14H14N2O5S2, shows that the geometry of the central bicyclic moiety is close to the geometry exhibited by other biologically active cephalosporin antibiotics. The molecules are arranged in a helical chain running parallel to the 21 axis via a strong O—H⋯O hydrogen bond. The main helices are zipped together via N—H⋯O interactions, forming infinite layers. The supramolecular architecture is stabilized by O—H⋯S and C—H⋯O hydrogen bonds. 相似文献
138.
Joanna Słowikowska Janusz Lipkowski 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(2):187-189
The structure of l -seryl-l -leucine, C9H18N2O4, has been determined and analysed in relation to the geometries of its amino acid constituents. The most important feature is the different conformational behaviour of the side chains at the Cβ atoms; a less pronounced discrepancy concerns the orientation of the C=O bond with respect to the Cα—N bond. The conformational preferences of these torsion angles are also established for related structures stored in the Cambridge Structural Database [Allen & Kennard (1993). Chem.Des.Autom. News, 8 , 1, 31–37]; the title structure compares well with these data. The molecules are organized in double layers, with the hydrophilic faces linked by an extensive hydrogen-bonding network, as in l -leucine. 相似文献
139.
The reaction of benzylthioarylboronic acids protected as N‐butyldiethanolamine esters or as triisopropoxyborates with organolithium bases or lithium diisopropylamide (LDA) has been investigated. The benzylic lithiation occurs selectively using LDA at − 68 °C. The stability of the resultant borio‐lithio intermediates is strongly influenced by the position of the boron atom in the phenyl ring. The reaction with various electrophiles affords new arylboronic acids substituted in the benzylic position. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
140.
Agnieszka Górska Halina Hajmowicz Tomasz Kliś Janusz Serwatowski Ludwik Synoradzki 《应用有机金属化学》2011,25(4):294-297
The reaction of arylboronic acids with L ‐O‐benzoyl‐tartaric acid and D ,L ‐malic acid has been studied. The obtained (acyloxy)boranes are moderately stable in solution and decompose to give boroxines. 5‐Carboxymethyl‐2‐(4‐methylthiophenyl)‐1,3,2‐dioxaborolan‐4‐one was obtained in the reaction of 4‐methylthiophenylboronic acid with D ,L ‐malic acid and characterized by X‐ray structural analysis. The use of L ‐(−)‐malic acid afforded the optically pure product which can be used as the powerful chiral reagent in the enantioselective reduction of ketones. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献