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991.
992.
We study analytically the approach to equilibrium in a simple zero-temperature model for phase separation in a binary alloy, in which nearest neighbor interchange can occur only if the portion of AB bonds is thereby decreased. The approach to equilibrium is found analytically. Because of the existence of infinitely many possible stationary states, the asymptotic distribution of AB pairs depends on the details of the initial state and must be obtained by a recursion method.Chargé de recherches FNRS. 相似文献
993.
An analytical solution for the model of drug distribution and absorption in small intestine 总被引:2,自引:0,他引:2
Xu Mingyu 《Acta Mechanica Sinica》1990,6(4):316-323
According to the physiological and anatomical characteristics of small intestine, neglecting the effect of its motility on
the distribution and absorption of drug and nutrient, Y. Miyamoto et al.[1] proposed a model of two-dimensional laminar flow in a circular porous tube with permeable wall and calculated the concentration
profile of drug by numerical analysis. In this paper, we give a steady state analytical solution of the above model including
deactivation term. The obtained results are in agreement with the results of their numerical analysis. Moreover the analytical
solution presented in this paper reveals the relation among the physiological parameters of the model and describes the basic
absorption rule of drug and nutrient through the intestinal wall and hence provides a theoretical basis for determining the
permeability and reflection coefficient through in situ experiments.
The project supported by NSF of Shandong Province 相似文献
994.
We establish the following converse to the Eidelheit theorem: an unbounded closed and convex set of a real Hilbert space may be separated by a closed hyperplane from every other disjoint closed and convex set, if and only if it has a finite codimension and a non-empty interior with respect to its affine hull. 相似文献
995.
The technique of choice for many types of forensic drug confirmations is gas chromatography/mass spectrometry (GC/MS). Significant amounts of analytical time can be involved in a GC/MS run. The use of a 0.1 mm i.d. fused silica capillary column with hydrogen carrier gas can significantly increase the speed of an analysis without sacrificing resolution. Nanogram levels of underivatized drugs, from amphetamine to strychnine, can be eluted in less than twelve minutes. The multitasking system permits data acquisition, while performing data reduction on the previous run. 相似文献
996.
Wilhelm Blödorn Robert Krismer Hugo M. Ortner Jens Stummeyer Peter Wilhartitz Gerold Wünsch 《Mikrochimica acta》1989,99(3-6):423-432
Trace metals (20 elements) in high-purity chromium, molybdenum and tungsten are collected and preconcentrated by precipitation and adsorption on cellulose collectors. The compound methods allow the application of AAS and ICP-AES as determination methods for the production control of highly pure refractory metals under routine conditions.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria 相似文献
997.
Extended Group Foliation Method and Functional Separation of Variables to Nonlinear Wave Equations 总被引:4,自引:0,他引:4
QU Chang-Zheng ZHANG Shun-Li 《理论物理通讯》2005,44(4):577-582
Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to nonlinear wave equations with variable speed and external force. A complete classification for the wave equation which admits functional separable solutions is presented. Some known results can be recovered by this approach. 相似文献
998.
999.
Laura Escuder‐Gilabert María Amparo Martínez‐Gómez Rosa María Villanueva‐Camañas Salvador Sagrado María José Medina‐Hernández 《Biomedical chromatography : BMC》2009,23(3):225-238
Stereoselectivity in protein binding can have a significant effect on the pharmacokinetic and pharmacodynamic properties of chiral drugs. The investigation of enantioselectivity of drugs in their binding with human plasma proteins and the identification of the molecular mechanisms involved in the stereodiscrimination by the proteins represent a great challenge for clinical pharmacology. In this review, the separation techniques used for enantioselective protein binding experiments are described and compared. An overview of studies on enantiomer–protein interactions, enantiomer–enantiomer interactions as well as chiral drug–drug interactions, including allosteric effects, is presented. The contribution of individual plasma proteins to the overall enantioselective binding and the animal species variability in drug–plasma protein binding stereoselectivity are reviewed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
1000.
Andrei Medvedovici Florin Albu Iuliana Daniela Sora Stefan Udrescu Toma Galaon Victor David 《Biomedical chromatography : BMC》2009,23(10):1092-1100
A sensitive method for determination of free captopril as monobromobimane derivative in plasma samples is discussed. The internal standard (IS) was 5‐methoxy‐1H‐benzimidazole‐2‐thiol. Derivatization with monobromobimane immediately after blood collection and plasma preparation prevents oxidation of captopril to the corresponding disulfide compound and enhances the ionization yield. Consequently, derivatization enhances sample stability and detection sensitivity. Addition of the internal standard was made immediately after plasma preparation. The internal standard was also derivatized by monobromobimane, as it contains a thiol functional group. Preparation of plasma samples containing captopril and IS derivatives was based upon protein precipitation through addition of acetonitrile, in a volumetric ratio 1:2. The reversed‐phase liquid chromatographic separation was achieved on a rapid resolution cartridge Zorbax SB‐C18, monitored through positive electrospray ionization and tandem MS detection using the multiple‐reaction monitoring mode. Transitions were 408–362 amu for the captopril derivative and 371–260 amu for the internal standard derivative. The kinetics of captopril oxidation to the corresponding disulfide compound in plasma matrix was also studied using the proposed method. A linear log–log calibration was obtained over the concentration interval 2.5–750 ng/mL. A low limit of quantitation in the 2.5 ng/mL range was obtained. The analytical method was fully validated and successfully applied in a three‐way, three‐period, single‐dose (50 mg), block‐randomized bioequivalence study for two pharmaceutical formulations (captopril LPH 25 and 50 mg) against the comparator Capoten 50 mg. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献