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991.
Oana Moncea Juan Casanova‐Chafer Didier Poinsot Lukas Ochmann Clve D. Mboyi Houssein O. Nasrallah Eduard Llobet Imen Makni Molka ElAtrous Stphane Brands Yoann Rousselin Bruno Domenichini Nicolas Nuns Andrey A. Fokin Peter R. Schreiner Jean‐Cyrille Hierso 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):10038-10043
Diamondoids, sp3‐hybridized nanometer‐sized diamond‐like hydrocarbons (nanodiamonds), difunctionalized with hydroxy and primary phosphine oxide groups, enable the assembly of the first sp3‐C‐based chemical sensors by vapor deposition. Both pristine nanodiamonds and palladium nanolayered composites can be used to detect toxic NO2 and NH3 gases. This carbon‐based gas sensor technology allows reversible NO2 detection down to 50 ppb and NH3 detection at 25–100 ppm concentration with fast response and recovery processes at 100 °C. Reversible gas adsorption and detection is compatible with 50 % humidity conditions. Semiconducting p‐type sensing properties are achieved from devices based on primary phosphine–diamantanol, in which high specific area (ca. 140 m2 g?1) and channel nanoporosity derive from H‐bonding. 相似文献
992.
Tawfiq NasrAllah Solne Savourey Jean‐Claude Berthet Emmanuel Nicolas Thibault Cantat 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11000-11003
The first iron catalysts able to promote the formal insertion of CO into the C?N bond of amines are reported. Using low‐valent iron complexes, including K2[Fe(CO)4], amides are formed from aromatic and aliphatic amines, in the presence of an iodoalkane promoter. Inorganic Lewis acids, such as AlCl3 and Nd(OTf)3, have a positive influence on the catalytic activity of the iron salts, enabling the carbonylation at a low pressure of CO (6 to 8 bars). 相似文献
993.
Maxime Jarret Victor Turpin Aurlien Tap Jean‐Franois Gallard Cyrille Kouklovsky Erwan Poupon Guillaume Vincent Laurent Evanno 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):9966-9970
Reported is the enantioselective total syntheses of mavacuran alkaloids, (+)‐taberdivarine H, (+)‐16‐hydroxymethyl‐pleiocarpamine, and (+)‐16‐epi‐pleiocarpamine, and their postulated biosynthetic precursor 16‐formyl‐pleiocarpamine. This family of monoterpene indole alkaloids is a target of choice since some of its members are subunits of intricate bisindole alkaloids such as bipleiophylline. Inspired by the biosynthetic hypothesis, an oxidative coupling approach from the geissoschizine framework to form the N1?C16 bond was explored. Quaternization of the aliphatic nitrogen center was key to achieving the oxidative coupling induced by KHMDS/I2 as it masks the nucleophilicity of the aliphatic nitrogen center and locks in the required cis conformation. 相似文献
994.
995.
Marie‐Pier Dinel Stefano Tartaggia Gregory Q. Wallace Denis Boudreau Jean‐Francois Masson Federico Polo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18370-18374
We report the integration of surface plasmon resonance (SPR), cyclic voltammetry and electrochemiluminescence (ECL) responses to survey the interfacial adsorption and energy transfer processes involved in ECL on a plasmonic substrate. It was observed that a Tween 80/tripropylamine nonionic layer formed on the gold electrode of the SPR sensor, while enhancing the ECL emission process, affects the electron transfer process to the luminophore, Ru(bpy)32+, which in turn has an impact on the plasmon resonance. Concomitantly, the surface plasmon modulated the ECL intensity, which decreased by about 40 %, due to an interaction between the excited state of Ru(bpy)32+ and the plasmon. This occurred only when the plasmon was excited, demonstrating that the optically excited surface plasmon leads to lower plasmon‐mediated luminescence and that the plasmon interacts with the excited state of Ru(bpy)32+ within a very thin layer. 相似文献
996.
Awatef Hattab Zoubeida Dhaouadi Alhadji Malloum Jean Jules Fifen Souad Lahmar Nino Russo Emilia Sicilia 《Journal of computational chemistry》2019,40(18):1707-1717
The possible isomers of [Mg(NH3)n = 1 − 10]+ clusters have been investigated using both M06-2X/6-31++G(d,p) and MP2/6-31++G(d,p) levels of theory. The isomeric distribution for each n size has been studied as a function of temperatures ranging from 25 to 400 K. To the best of our knowledge, for clusters size n > 6, this is the first theoretical study available in the literature. From the calculated values in the considered clusters and using a fitting procedure, we have evaluated the binding energies (−14.0 kcal/mol), clustering energies (−10.1 kcal/mol), clustering free energies (−2.8 kcal/mol), and clustering enthalpies (−10.3 kcal/mol). On the basis of our structural and infrared (IR) spectroscopy outcomes, we find that the first solvation shell can hold up to six ammonia molecules. © 2019 Wiley Periodicals, Inc. 相似文献
997.
Amandine Pons Jean Michalland Wojciech Zawodny Yong Chen Veronica Tona Nuno Maulide 《Angewandte Chemie (International ed. in English)》2019,58(48):17303-17306
The ability of silicon to stabilize vinyl cationic species leads to a redox arylation of alkynes whereby the stringent limitations of reactivity and regioselectivity of alkyl‐substituted alkynes are lifted. This allows the synthesis of a range of α‐silyl‐α′‐arylketones under mild conditions in good to excellent yields and with high functional group tolerance, whereby the silicon moiety in the final products can either be removed for a formal acetone monoarylation transform, or capitalized upon for subsequent electrophilic substitutions at either side of the carbonyl group. 相似文献
998.
Jean Quertinmont Prof. Dr. Tom Leyssens Prof. Dr. Johan Wouters Prof. Dr. Benoît Champagne 《Chemphyschem》2019,20(19):2434-2442
This work aims at better understanding the complex effects of co-crystallization on a single salicylideneaniline molecular switch, (E)-2-methoxy-6-(pyridine-3-yliminomethyl)phenol (PYV3), which can tautomerize between an enol and a keto form. A combination of periodic boundary conditions DFT and molecular wavefunction calculations has been adopted for examining a selection of PYV3 co-crystals, presenting hydrogen bonds (H-bonds) or halogen bonds (X-bonds), for which X-ray diffraction data are available. Three aspects are targeted: i) the energy (H-bond strength, enol to keto relative energy, and geometry relaxation energies), ii) the geometrical structure (PYV3 to co-crystal and enol to keto geometrical variations), and iii) the electron distribution (PYV3 to co-crystal and enol to keto Mulliken charge variations). These allow i) explaining the preference for forming H-bonds with the nitrogen of the pyridine of PYV3 with respect to the oxygens and the importance of the crystal field, ii) distinguishing the peculiar behavior of the SulfonylDiPhenol (SDP) coformer, which stabilizes the keto form of PYV3, iii) describing the relative stabilization of the enol form upon co-crystallization (with the exception of SDP) and therefore iv) substantiating the co-crystallization-induced reduction of thermochromism observed for several PYV3 co-crystals. 相似文献
999.
Druart G Taboury J Guérineau N Haïdar R Sauer H Kattnig A Primot J 《Optics letters》2008,33(4):366-368
Diffractive axicons are optical components producing achromatic nondiffracting beams. They thus produce a focal line rather than a focal point for classical lenses. This gives the interesting property of a long focal depth. We show that this property can be used to design a simple imaging system with a linear variable zoom by using and translating a diffractive axicon as the only optical component. 相似文献
1000.
We study the asymptotics of solutions of the Boltzmann equation describing the kinetic limit of a lattice of classical interacting
anharmonic oscillators. We prove that, if the initial condition is a small perturbation of an equilibrium state, and vanishes
at infinity, the dynamics tends diffusively to equilibrium. The solution is the sum of a local equilibrium state, associated
to conserved quantities that diffuse to zero, and fast variables that are slaved to the slow ones. This slaving implies the
Fourier law, which relates the induced currents to the gradients of the conserved quantities.
Partially supported by the Belgian IAP program P6/02.
Partially supported by the Academy of Finland. 相似文献