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71.
The reactivity of stereochemically defined 3-aryl-2-chloro-2-imidoylaziridines, an unexplored class of substituted aziridines, was investigated under various reaction conditions. 2-Chloro-2-imidoylaziridines underwent a novel thermal rearrangement by reflux in acetonitrile via C-C bond cleavage to 4-chloro-2,5-diarylimidazoles in high yield. Alternatively, a novel efficient entry toward 2-aroyl-2-chloroaziridines was based on the chemoselective hydrolysis of 2-chloro-2-imidoylaziridines with hydrochloric acid in aqueous tetrahydrofuran. 相似文献
72.
73.
Four novel fully π-conjugated α,ω-bis(terpyridine)oligothiophenes characterized by NMR, IR, and HR-mass spectroscopy are presented and their electronic absorption/emission and redox properties are described based on both experiments and theoretical calculations. These compounds can be potentially utilized as building blocks for preparation of conjugated metallo-supramolecular polymers or dynamers and related functional materials. 相似文献
74.
Hansell CF Espeel P Stamenović MM Barker IA Dove AP Du Prez FE O'Reilly RK 《Journal of the American Chemical Society》2011,133(35):13828-13831
Herein we report the use of a tetrazine-norbornene inverse electron demand Diels-Alder conjugation applied to polymer end-functionalization and polymer-polymer coupling. The reaction was found to be applicable to polymer-polymer coupling, as judged by SEC, DOSY NMR, and LCxSEC analyses, giving diblock copolymers by merely mixing the constituent homopolymers together under ambient conditions, using no catalyst, additive, or external stimulus. 相似文献
75.
Čížková M Kolivoška V Císařová I Šaman D Pospíšil L Teplý F 《Organic & biomolecular chemistry》2011,9(2):450-462
A modular approach to the construction of monocationic quaternary N-heteroaromatic frameworks was developed capitalizing on a direct pyridine-type nitrogen quaternization followed by metal-catalyzed [2+2+2] cycloaddition with gaseous acetylene. The flexibility of the route is demonstrated on 12 diverse scaffolds based on pyridinium, quinolinium, thiazolium, benzothiazolium, imidazolium, and pyrimidinium. Electrochemical study revealed a quinolinium redox system with two electrochemically distinct forms that are interconverted by a homogeneous chemical reaction triggered by fast electron transfers (reduction at -0.7 V and oxidation at -0.05 V). 相似文献
76.
Colpaert F Mangelinckx S Rocchetti MT De Kimpe N 《Organic & biomolecular chemistry》2011,9(2):549-558
α-Methoxy- and α-ethoxyketones, as important intermediates in organic synthesis and flavor compounds in food chemistry, were synthesized by deprotonation of N-(1-alkoxy-2-propylidene)isopropylamine, prepared by condensation of the corresponding α-alkoxyacetone with isopropylamine, and subsequent reaction of the corresponding 1-azaallylic anions with alkyl halides to afford α'-alkylated, α-alkylated and α,α'-dialkylated ketimines. Hydrolysis of the imino function led to the desired substituted α-alkoxyketones. The ratio of α-, α'-, and α,α'-(di)alkylated compounds depended on the amount of base used and on the nature of the alkylating reagent. 相似文献
77.
Dependence of surface potential (electrostatic potential at the inner Helmholtz plane, Ψ(0)) at the silver bromide aqueous electrolyte interface was measured as a function of the activities of Br(-) and Ag(+) by using a single crystal silver bromide electrode (SCr-AgBr). Absolute values of surface potentials were obtained from electrode potentials of SCr-AgBr and isoelectric points. Measurements were performed at different temperatures in the range from 10 to 50°C. Corresponding equilibrium constants of interfacial reactions were obtained using the surface complexation model and interpreted via the van't Hoff equation. As a result of the interpretation for the binding of bromide ions leading to a negative surface charge, the thermodynamic parameters obtained were Δ(n)H(°)=-33kJmol(-1) and Δ(n)S(°)=-31Jmol(-1)K(-1); and for the binding of silver ions leading to a positive surface charge, Δ(p)H(°)=-72kJmol(-1) and Δ(p)S(°)=-196Jmol(-1)K(-1). Association of counterions (CI) with oppositely charged surface sites partially compensates the surface charge. Assuming approximately the same affinities for anions (NO(3)(-)) and cations (K(+)) thermodynamic parameters for their binding were obtained as Δ(CI)H(°)≈7kJmol(-1) and Δ(CI)S(°)≈105Jmol(-1)K(-1). 相似文献
78.
Hvasanov D Wiedenmann J Braet F Thordarson P 《Chemical communications (Cambridge, England)》2011,47(22):6314-6316
In contrast to simple salts or negatively charged macromolecules, positively charged proteins and peptides including cytochrome c (yeast) and poly-L-lysine are efficiently encapsulated while inducing the formation of polymersomes from polystyrene(140)-b-poly(acrylic acid)(48) (PS(140)-b-PAA(48)). 相似文献
79.
Soft robotics for chemists 总被引:3,自引:0,他引:3
Ilievski F Mazzeo AD Shepherd RF Chen X Whitesides GM 《Angewandte Chemie (International ed. in English)》2011,50(8):1890-1895
80.
Filip Rindler 《Archive for Rational Mechanics and Analysis》2011,202(1):63-113
We establish a general weak* lower semicontinuity result in the space BD(Ω) of functions of bounded deformation for functionals
of the form
$ {ll} \,\mathcal{F}(u) := &\int_\Omega f (x, \mathcal{E} u) \;{\rm d} x + \int_\Omega f^\infty \left( x, \frac{{\rm d} E^s u}{{\rm d} |{E^s u}|} \right) \;{\rm d} |{E^s u}| \\ &+ \int_{\partial \Omega} f^\infty \left( x, u|_{\partial \Omega} \odot n_\Omega \right) \;{\rm d} \mathcal{H}^{d-1}, \qquad u \in {\rm BD}(\Omega). $ \begin{array}{ll} \,\mathcal{F}(u) := &\int_\Omega f (x, \mathcal{E} u) \;{\rm d} x + \int_\Omega f^\infty \left( x, \frac{{\rm d} E^s u}{{\rm d} |{E^s u}|} \right) \;{\rm d} |{E^s u}| \\ &+ \int_{\partial \Omega} f^\infty \left( x, u|_{\partial \Omega} \odot n_\Omega \right) \;{\rm d} \mathcal{H}^{d-1}, \qquad u \in {\rm BD}(\Omega). \end{array} 相似文献 |