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41.
We investigate certain geometric properties of the spaces of idempotent measures. In particular, we prove that the space of idempotent measures on an infinite compact metric space is homeomorphic to the Hilbert cube. 相似文献
42.
María Álvarez de Morales Lidia Fernández Teresa E. Pérez Miguel A. Piñar 《Numerical Algorithms》2007,45(1-4):153-166
In this paper, we consider bivariate orthogonal polynomials associated with a quasi-definite moment functional which satisfies
a Pearson-type partial differential equation. For these polynomials differential properties are obtained. In particular, we
deduce some structure and orthogonality relations for the successive partial derivatives of the polynomials.
相似文献
43.
Asymmetric Synthesis of Fluorinated Isoindolinones through Palladium‐Catalyzed Carbonylative Amination of Enantioenriched Benzylic Carbamates
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Dr. Pablo Barrio Ignacio Ibáñez Lidia Herrera Dr. Raquel Román Dr. Silvia Catalán Prof. Dr. Santos Fustero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11579-11584
The asymmetric synthesis of fluorinated isoindolinones has been achieved by a palladium‐catalyzed aminocarbonylation reaction of the corresponding α‐fluoroalkyl o‐iodobenzylamines. A base‐mediated anti β‐hydride elimination process was suggested to explain the partial erosion of the optical purity observed in some cases. This mechanistic rationale enabled the minimization of this partial racemization by fine‐tuning the pKa of the base. 相似文献
44.
45.
Lidia Zapa?a 《Journal of solution chemistry》2011,40(2):198-210
In this paper, the flufenamic acid equilibria in aqueous solution and in two-phase organic solvent + aqueous solution are described and presented. The dissociation constants K a1 and K a2 were determined in MDM + water mixtures. The Yashuda-Shedlovsky extrapolation procedure has been used to obtain the values of K a1 and K a2 in aqueous solutions. The distribution ratio D was measured in the toluene + water system over a wide range of pH by the shaking flask method. Based on the results of potentiometric titrations in two-phase organic solvent (benzene, ethylbenzene, toluene, carbon tetrachloride, chloroform, chlorobenzene, and bromobenzene) + aqueous systems, and using models of single and multistep equilibria, the values of distribution constants K D and dimerization constants K dim were calculated. The influences of polarity of the applied solvents and pH of the aqueous phase, on the speciation of the particular forms of flufenamic acid in both phases, were demonstrated. 相似文献
46.
Gabrieli L. ParrilhaAuthor VitaeRafael P. VieiraAuthor Vitae Anayive P. RebolledoAuthor VitaeIsolda C. MendesAuthor Vitae Lidia M. LimaAuthor VitaeEliezer J. BarreiroAuthor Vitae Oscar E. PiroAuthor VitaeEduardo E. CastellanoAuthor Vitae Heloisa BeraldoAuthor Vitae 《Polyhedron》2011,30(11):1891-1898
Complexes [Zn2(HL1)2(CH3COO)2] (1) and [Zn2(L2)2] (2) were synthesized with salicylaldehyde semicarbazone (H2L1) and salicylaldehyde-4-chlorobenzoyl hydrazone (H2LASSBio-1064, H2L2), respectively. The crystal structure of (1) was determined. Upon recrystallization of previously prepared [Zn2(HL2)2(Cl)2] (3) in 1:9 DMSO:acetone crystals of [Zn2(L2)2(H2O)2]·[Zn2(L2)2(DMSO)4] (3a) were obtained. The crystal structure of 3a was also determined. All crystal structures revealed the presence of phenoxo-bridged binuclear zinc(II) complexes. 相似文献
47.
A one-pot two-step microwave assisted synthesis of variously disubstituted 1,2,4-oxadiazoles from carboxylic acids and amidoximes is reported. This methodology is characterized by short reaction times, is versatile, robust and high-yielding and allows for the preparation of heterocycles with a stereocenter with 100% enantiomeric purity. 相似文献
48.
Liquid phase microextraction applications in food analysis 总被引:2,自引:0,他引:2
Asensio-Ramos M Ravelo-Pérez LM González-Curbelo MÁ Hernández-Borges J 《Journal of chromatography. A》2011,1218(42):7415-7437
Over the last years, liquid-phase microextraction (LPME) in its different application modes (single drop microextraction, dispersive liquid-liquid microextraction and hollow fiber-LPME) has been increasingly applied for the extraction of both inorganic and organic analytes from different matrices. Its advantages over conventional extraction procedures (simplicity, effectiveness, rapidity and low consumption of organic solvents) has also attracted its application in the complex food analysis field, in which it has clearly provided good and challenging results. A comprehensive review dealing with those articles published since its introduction till the end of March 2011 is presented, offering also a critical vision of the analytical potential of LPME for the analysis of foods. 相似文献
49.
We present a rigorous analysis of the performance of some one-step discretization schemes for a class of PT-symmetric singular
boundary eigenvalue problem which encompasses a number of different problems whose investigation has been inspired by the
2003 article of Benilov et al. (J Fluid Mech 497:201–224, 2003). These discretization schemes are analyzed as initial value problems rather than as discrete boundary problems, since this
is the setting which ties in most naturally with the formulation of the problem which one is forced to adopt due to the presence
of an interior singularity. We also devise and analyze a variable step scheme for dealing with the singular points. Numerical
results show better agreement between our results and those obtained from small-ϵ asymptotics than has been shown in results presented hitherto. 相似文献
50.
Lidia Smentek-Mielczarek 《Molecular physics》2013,111(3):767-774
A complete expression for the f?f transition amplitude defined up to the third order in perturbation theory is presented. The third-order contributions are due to electron correlation inside the rare earth ion and arise from the static and dynamic models. The approach is formulated by means of double perturbation theory and in terms of effective tensor operators expressed by unit tensor operators. The discussion of the relative importance of various kinds of effective operators is based on the numerical results of test ab initio calculations performed within the perturbed function approach for the Pr+3 ion. 相似文献