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101.
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Paolo Della Porta Riccardo Zanasi Guglielmo Monaco 《Journal of computational chemistry》2015,36(10):707-716
Current density plots of closed‐shell intermolecular H? H interactions characterized by a bond critical point (BCP) show two vortices separated by a saddle, a pattern which allows for a clear definition of a pair current strength. This H? H current strength turns out to be roughly related to the potential energy density at the BCP and then to the dissociation energy. The same pattern is also recognizable, at least for an azimuthal orientation of a field perpendicular to the H? H line, for the intramolecular interactions previously investigated to propose the H? H bonding. In the case of the H atoms of the bay region of polycyclic aromatic hydrocarbons, the current of the H? H delocalized diatropic vortex gives a quantitative indication of stabilization; however, on rotation of the field and the subsequent onset of a bay‐delocalized paratropic vortex (a typical signature of antiaromaticity), the diatropic vortex can be reshaped or it can even disappear, consistently with its smallness, and thus showing the effect of other more relevant interactions. © 2015 Wiley Periodicals, Inc. 相似文献
104.
Massimiliano Berti Riccardo Montalto 《Journal of Fixed Point Theory and Applications》2017,19(1):129-156
We present the result and the ideas of the recent paper (Berti and Montalto, Quasi-periodic standing wave solutions of gravity-capillary water waves, http://arxiv.org/abs/1602.02411, 2016) concerning the existence of Cantor families of small-amplitude time quasi-periodic standing wave solutions (i.e. periodic and even in the space variable x) of a 2-dimensional ocean, with infinite depth, in irrotational regime, under the action of gravity and surface tension at the free boundary. These quasi-periodic solutions are linearly stable. 相似文献
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Dietrich PM Horlacher T Girard-Lauriault PL Gross T Lippitz A Min H Wirth T Castelli R Seeberger PH Unger WE 《Langmuir : the ACS journal of surfaces and colloids》2011,27(8):4808-4815
Carbohydrate films on gold based on dimannoside thiols (DMT) were prepared, and a complementary surface chemical analysis was performed in detail by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), near-edge X-ray absorption fine structure (NEXAFS), FT-IR, and contact angle measurements in order to verify formation of ω-carbohydrate-functionalized alkylthiol films. XPS (C 1s, O 1s, and S 2p) reveals information on carbohydrate specific alkoxy (C-O) and acetal moieties (O-C-O) as well as thiolate species attached to gold. Angle-resolved synchrotron XPS was used for chemical speciation at ultimate surface sensitivity. Angle-resolved XPS analysis suggests the presence of an excess top layer composed of unbound sulfur components combined with alkyl moieties. Further support for DMT attachment on Au is given by ToF-SIMS and FT-IR analysis. Carbon and oxygen K-edge NEXAFS spectra were interpreted by applying the building block model supported by comparison to data of 1-undecanethiol, poly(vinyl alcohol), and polyoxymethylene. No linear dichroism effect was observed in the angle-resolved C K-edge NEXAFS. 相似文献
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108.
Amorati R Attanasi OA Favi G Menichetti S Pedulli GF Viglianisi C 《Organic & biomolecular chemistry》2011,9(5):1352-1355
Hydrogenated cardanol and cardols, contained in industrial grade cardanol oil and obtained by distillation of the raw "cashew nut shell liquid" (CNSL), are easily transformed into efficient 4-thiaflavane antioxidants bearing a long alkyl chain on A ring and a catechol group on B ring. 相似文献
109.
In recent years fluorescence microscopy has become a widely used tool for tissue imaging and spectroscopy. Optical techniques,
based on both linear and non-linear excitation, have been broadly applied to imaging and characterization of biological tissues.
Among fluorescence techniques used in tissue imaging applications, in recent years two and three-photon excited fluorescence
have gained increased importance because of their high-resolution deep tissue imaging capability inside optically turbid samples.
The main limitation of steady-state fluorescence imaging techniques consists in providing only morphological information;
functional information is not detectable without technical improvements. A spectroscopic approach, based on lifetime measurement
of tissue fluorescence, can provide functional information about tissue conditions, including its environment, red-ox state,
and pH, and hence physiological characterization of the tissue under investigation. Measurement of the fluorescence lifetime
is a very important issue for characterizing a biological tissue. Deviation of this property from a control value can be taken
as an indicator of disorder and/or malignancy in diseased tissues. Even if much work on this topic has still to be done, including
the interpretation of fluorescence lifetime data, we believe that this methodology will gain increasing importance in the
field of biophotonics. In this paper, we review methodologies, potentials and results obtained by using fluorescence lifetime
imaging microscopy for the investigation of biological tissues. 相似文献
110.
Odendaal AY Fiamengo AL Ferdani R Wadas TJ Hill DC Peng Y Heroux KJ Golen JA Rheingold AL Anderson CJ Weisman GR Wong EH 《Inorganic chemistry》2011,50(7):3078-3086
Ethylene cross-bridged tetraamine macrocycles are useful chelators in coordination, catalytic, medicinal, and radiopharmaceutical chemistry. Springborg and co-workers developed trimethylene cross-bridged analogues, although their pendant-armed derivatives received little attention. We report here the synthesis of a bis-carboxymethyl pendant-armed cyclen with a trimethylene cross-bridge (C3B-DO2A) and its isomeric ethylene-cross-bridged homocyclen ligand (CB-TR2A) as well as their copper(II) complexes. The in vitro and in vivo properties of these complexes are compared with respect to their potential application as (64)Cu-radiopharmaceuticals in positron emission tomography (PET imaging). The inertness of Cu-C3B-DO2A to decomplexation is remarkable, exceeding that of Cu-CB-TE2A. Electrochemical reduction of Cu-CB-TR2A is quasi-reversible, whereas that of Cu-C3B-DO2A is irreversible. The reaction conditions for preparing (64)Cu-C3B-DO2A (microwaving at high temperature) are relatively harsh compared to (64)Cu-CB-TR2A (basic ethanol). The in vivo behavior of the (64)Cu complexes was evaluated in normal rats. Rapid and continual clearance of (64)Cu-CB-TR2A through the blood, liver, and kidneys suggests relatively good in vivo stability, albeit inferior to (64)Cu-CB-TE2A. Although (64)Cu-C3B-DO2A clears continually, the initial uptake is high and only about half is excreted within 22 h, suggesting poor stability and transchelation of (64)Cu to proteins in the blood and/or liver. These data suggest that in vitro inertness of a chelator complex may not always be a good indicator of in vivo stability. 相似文献