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991.
Sbastien Blanchard Loïc Le Clainche Marie-Noëlle Rager Benoît Chansou Jean-Pierre Tuchagues Arthur F. Duprat Yves Le Mest Olivia Reinaud 《Angewandte Chemie (International ed. in English)》1998,37(19):2732-2735
A cavity that acts as a molecular funnel is formed from calix[6]arene 1 and [CuI(NCCH3)4]PF6 [Eq. (a)]. An exchange of the well-protected acetonitrile ligand for other nitriles RCN is only possible with small R groups. The protection of the copper ions precludes oxidative dimerization; thus, the complexes mimic the mononuclear site of copper enzymes. 相似文献
992.
Aarnoud L. Roest Dr. Alexander Germeau Dr. John J. Kelly Daniël Vanmaekelbergh Prof. Guy Allan Dr. Eric A. Meulenkamp Dr. 《Chemphyschem》2003,4(9):959-966
We have studied the storage and long-range transport of electrons in a porous assembly of weakly coupled ZnO quantum dots permeated with an aqueous and a propylene carbonate electrolyte solution. The number of electrons per ZnO quantum dot is controlled by the electrochemical potential of the assembly; the charge of the electrons is compensated by ions present in the pores. We show with optical and electrical measurements that the injected electrons occupy the S, P, and D type conduction electron levels of the quantum dots; electron storage in surface states is not important. With this method of three-dimensional charge compensation, up to ten electrons per quantum-dot can be stored if the assembly is permeated with an aqueous electrolyte. The screening of the electron charge is less effective in the case of an assembly permeated with a propylene carbonate electrolyte solution. Long-range electron transport is studied with a transistor set-up. In the case of ZnO assemblies permeated with an aqueous electrolyte, two quantum regimes are observed corresponding to multiple tunnelling between the S orbitals (at a low occupation) and P orbitals (at a higher occupation). In a ZnO quantum-dot assembly permeated with a propylene carbonate electrolyte solution, there is a strong overlap between these two regimes. 相似文献
993.
Younes Makoudi Eric Duverger Dr. Madjid Arab Dr. Frédéric Chérioux Dr. Franscisco Ample Dr. Gwénaël Rapenne Dr. Xavier Bouju Dr. Frank Palmino Dr. 《Chemphyschem》2008,9(10):1437-1441
This work describes an innovative concept for the development of organized molecular systems based on the template effect of the pre‐structured semi‐conductive SmSi(111) interface. This substrate is selected because Sm deposition in the submonolayer range leads to a 8×2‐reconstruction, which is a well‐defined one‐dimensional semi‐metallic structure. Adsorption of aromatic molecules [1,4‐di‐(9‐ethynyltriptycenyl)‐benzene] on SmSi(111)‐ 8×2 and Si(111)‐7×7 interfaces is investigated by scanning tunneling microscopy (STM) at room temperature. Density functional theory (DFT) and semi‐empirical (ASED+) calculations define the nature of the molecular adsorption sites of the target molecule on SmSi as well as their self‐alignment on this interface. Experimental data and theoretical results are in good agreement. 相似文献
994.
995.
Emilio Pardo Dr. Danielle Cangussu Dr. Marie-Claire Dul Rodrigue Lescouëzec Dr. Patrick Herson Yves Journaux Dr. Emerson F. Pedroso Dr. Cynthia L. M. Pereira Dr. M. Carmen Muñoz Prof. Dr. Rafael Ruiz-García Dr. Joan Cano Dr. Pedro Amorós Prof. Dr. Miguel Julve Prof. Dr. Francesc Lloret Prof. Dr. 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2008,120(22):4279-4284
996.
Gaëtan R. P. Henry Xavier Drooghaag Dimitri D. J. Rousseaux Michel Sclavons Jacques Devaux Jacqueline Marchand‐Brynaert Véronique Carlier 《Journal of polymer science. Part A, Polymer chemistry》2008,46(9):2936-2947
This study reports a reactive extrusion process leading to very high levels of anhydride grafting (2.5–3 wt %) along polypropylene backbone without recovering grafted PP waxes at the die exit. Such high graftings are attainable without excessive degradation of the PP chain by using a brominated reagent. Simultaneously, this brominated reagent allows the tuning of the grafted PP crystallinity via epimerization of the PP backbone. Indeed, the synthesis of a mainly isotactic/atactic stereoblock polymer containing high levels of grafted succinic anhydride moieties is demonstrated by NMR and melting enthalpies recorded by DSC are definitely observed depressed and broadened. Grafting levels of around 3 wt % have been achieved and ascertained by both chemical titration and NMR spectroscopy. In addition, FTIR spectroscopy reveals an unusual observation: for the first time, only one single pair of symmetric and asymmetric carbonyl stretching bands are observed on those grafted PP, while, in other processes of anhydride grafting, those symmetric and asymmetric bands were both split in at least two bands. This suggests, for the here reported process, the absence of interacting grafted anhydride rings, i.e., absence of closely grafted anhydride moieties and absence of poly(maleic anhydride). All those observations support that this “bromine route” brings a really new grafting process for PP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2936–2947, 2008 相似文献
997.
Richard I. Duclos Jr. 《Tetrahedron letters》2008,49(39):5587-5589
Analogously to the fenchyl and adamantyl groups, the bornyl and epimeric isobornyl groups are compact lipophilic substituents that can be incorporated into drug design to improve pharmacological or physicochemical properties. Methods are reported for the synthesis and characterization of 2-substituted norbornanes and bornanes that can serve as novel cannabinergic ligand intermediates. 相似文献
998.
Gaëtan R. P. Henry Xavier Drooghaag Mikhaël Vandeuren Michel Sclavons André Schanck Jacques Devaux Véronique Carlier Jacqueline Marchand‐Brynaert 《Journal of polymer science. Part A, Polymer chemistry》2009,47(18):4505-4518
Amorphous and low crystallinity polypropylenes were produced by reactive processing of commercial isotactic polypropylenes in the presence of a peroxide (2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane) and N‐bromosuccinimide. Characterization of the modified polypropylene microstructures using 13C NMR spectroscopy revealed that crystallinity loss is correlated with the epimerization of numerous methynes randomly along the polymer backbone, leading to decreasing isotacticities ([mmmm]) and average isotactic block lengths. Moreover, degradation usually induced by peroxide was shown to be comparatively limited in additional presence of N‐bromosuccinimide. This fast and easy process therefore allows the production of polypropylene plastomers and elastomers with controlled and homogeneous crystallinities and isotacticities, and relatively low molecular weight distributions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4505–4518, 2009 相似文献
999.
Simon Clavaguera Olivier J. Dautel Lionel Hairault Christophe Méthivier Pierre Montméat Eric Pasquinet Claire‐Marie Pradier Françoise Serein‐Spirau Salem Wakim Florian Veignal Joël J. E. Moreau Jean‐Pierre Lère‐Porte 《Journal of polymer science. Part A, Polymer chemistry》2009,47(16):4141-4149
The detection of 2,4‐dinitrotoluene (DNT) by fluorescence quenching of a new class of polyimines consisting in π‐conjugated segments regularly alternated with chiral C2 symmetry units has been studied for solutions and thin films. Their photophysical properties and their sensitivity towards DNT detection has been compared to those of a small model molecule incorporating the same π‐conjugated segment. In solution, all the compounds exhibit the same photo‐physical properties and sensitivity towards DNT detection. In contrast, for thin films, better performances are observed in static conditions for this new class of polyimines compared to the small model molecule. It seems that C2 symmetry units prevent from the stacking of the π‐conjugated segments and provide in addition to high fluorescence signal an improved diffusion of the analyte inside the films. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4141–4149, 2009 相似文献