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Zartler ER Hanson J Jones BE Kline AD Martin G Mo H Shapiro MJ Wang R Wu H Yan J 《Journal of the American Chemical Society》2003,125(36):10941-10946
The crucial step in drug discovery is the identification of a lead compound from a vast chemical library by any number of screening techniques. NMR-based screening has the advantage of directly detecting binding of a compound to the target. The spectra resulting from these screens can also be very complex and difficult to analyze, making this an inefficient process. We present here a method, RAMPED-UP NMR, (Rapid Analysis and Multiplexing of Experimentally Discriminated Uniquely Labeled Proteins using NMR) which generates simple spectra which are easy to interpret and allows several proteins to be screened simultaneously. In this method, the proteins to be screened are uniquely labeled with one amino acid type. There are several benefits derived from this unique labeling strategy: the spectra are greatly simplified, resonances that are most likely to be affected by binding are the only ones observed, and peaks that yield little or no information upon binding are eliminated, allowing the analysis of multiple proteins easily and simultaneously. We demonstrate the ability of three different proteins to be analyzed simultaneously for binding to two different ligands. This method will have significant impact in the use of NMR spectroscopy for both the lead generation and lead optimization phases of drug discovery by its ability to increase screening throughput and the ability to examine selectivity. To the best of our knowledge, this is the first time in any format that multiple proteins can be screened in one tube. 相似文献
54.
Two synthetic routes have been introduced and evaluated for the preparation of hydrophilic silica-based monoliths possessing surface-bound cyano functions. In one synthetic scheme, the silica monolith was reacted in a single step with 3-cyanopropyldimethylchlorosilane to yield a cyano phase referred to as CN-monolith. In a second synthetic route, the silica monolith was first reacted with gamma-glycidoxypropyltrimethoxysilane (gamma-GPTS), followed by a reaction with 3-hydroxypropionitrile (3-HPN) to give a stationary phase denoted CN-OH-monolith. Although the gamma-GPTS was intended to play the role of a spacer arm to link the 3-HPN to the silica surface, this spacer arm became an integral part of the hydrophilic stationary phase. Thus, the CN-OH-monolith can be viewed as a double-layered stationary phase (i.e., stratified phase) with a hydroxy sub-layer and a cyano top layer. Due to its stronger hydrophilic character, the CN-OH-monolith yielded higher retention and better selectivity than the CN-monolith. The CN-OH-monolith was demonstrated in the normal-phase capillary electrochromatography (CEC) of various polar compounds including phenols and chloro-substituted phenols, nucleic acid bases, nucleosides, and nitrophenyl derivatives of mono- and oligosaccharides. The CN-OH-monolith yielded a relatively strong electroosmotic flow over a wide range of mobile phase composition, thus allowing rapid separation of the polar compounds studied. 相似文献
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Hill RT Lyon JL Allen R Stevenson KJ Shear JB 《Journal of the American Chemical Society》2005,127(30):10707-10711
The functionality and structural diversity of biological macromolecules has motivated efforts to exploit proteins and DNA as templates for synthesis of electronic architectures. Although such materials offer promise for numerous applications in the fabrication of cellular interfaces, biosensors, and nanoelectronics, identification of techniques for positioning and ordering bioelectronic components into useful patterns capable of sophisticated function has presented a major challenge. Here, we describe the fabrication of electronic materials using biomolecular scaffolds that can be constructed with precisely defined topographies. In this approach, a tightly focused pulsed laser beam capable of promoting protein photo-cross-linking in specified femtoliter volume elements is scanned within a protein solution, creating biomolecular matrices that either remain in integral contact with a support surface or extend as free-standing structures through solution, tethered at their ends. Once fabricated, specific protein scaffolds can be selectively metallized via targeted deposition and growth of metal nanoparticles, yielding high-conductivity bioelectronic materials. This aqueous fabrication strategy opens new opportunities for creating electronic materials in chemically sensitive environments and may offer a general approach for creating microscopically defined inorganic landscapes. 相似文献
57.
The carbocyclic analog (VI) of cytidine was prepared from the carbocyclic analog (I) of uridine. The intermediate stages were a tetrabenzoyl derivative of I, the tribenzoyl derivative of the uridine analog, and the tribenzoyl 4-chloropyrimidinone obtained from the latter derivative. The cytidine analog (VI) is active against KB cells in culture and against L1210 leukemia in mice. In the initial tests against L1210 leukemia, the highest dose (200 mg./kg./day, q.d. 1-9), of three active doses, increased lifespan by 82% and showed no evidence of toxicity. 相似文献
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The effect of destroying carbonyl and hydroperoxide groups in oxidised polypropylene on the subsequent rate of photo-oxidation has been examined using infra-red spectroscopy. The results show that carbonyl groups dominate the rate of photo-oxidation in severely oxidised polymer. In mildly oxidised polymer hydroperoxide groups control the rate, but to a much smaller extent. Destruction of the photo-active carbonyl and hydroperoxide groups in the unoxidised and oxidised polymers by prior photolysis in an inert atmosphere gave rise to some interesting and complex effects on subsequent photo-oxidation. The results indicate that although carbonyl and hydroperoxide groups may control the rates of photo-oxidation of thermally oxidised/processed polymer, their importance as primary photo-initiators is highly questionable. Oxygen-polymer charge transfer complexes appear to be the more likely photo-initiators. 相似文献
59.
Kimberly A. Carter-Fenk Kevin Carter-Fenk Michelle E. Fiamingo Heather C. Allen John M. Herbert 《Chemical science》2021,12(24):8320
Surface-sensitive vibrational spectroscopy is a common tool for measuring molecular organization and intermolecular interactions at interfaces. Peak intensity ratios are typically used to extract molecular information from one-dimensional spectra but vibrational coupling between surfactant molecules can manifest as signal depletion in one-dimensional spectra. Through a combination of experiment and theory, we demonstrate the emergence of vibrational exciton delocalization in infrared reflection–absorption spectra of soluble and insoluble surfactants at the air/water interface. Vibrational coupling causes a significant decrease in peak intensities corresponding to C–F vibrational modes of perfluorooctanoic acid molecules. Vibrational excitons also form between arachidic acid surfactants within a compressed monolayer, manifesting as signal reduction of C–H stretching modes. Ionic composition of the aqueous phase impacts surfactant intermolecular distance, thereby modulating vibrational coupling strength between surfactants. Our results serve as a cautionary tale against employing alkyl and fluoroalkyl vibrational peak intensities as proxies for concentration, although such analysis is ubiquitous in interface science.Coupling between surfactant molecules at the air/water interface bleeds intensity into a diffuse background, such that single-wavelength vibrational intensity is effectively depleted at high surface coverage. 相似文献
60.
Norman S. Allen Alan Parkinson Frank F. Loffelman Peter V. Susi 《Polymer Degradation and Stability》1983,5(6):403-413
The photo-chemical behaviour of a number of mono- and polyfunctional commercial phenolic antioxidants has been examined using kinetic micro-second flash photolysis. The technique provides useful information on the relationship between antioxidant structure and the efficiency of phenoxy radical production. The kinetics of decay of the phenoxy radicals are also found to be dependent on structure. Mono-functional antioxidants give phenoxy radicals which decay by a second-order process whereas polyfunctional antioxidants give phenoxy radicals that decay by a first-order process. In the former case dimerisation to give bisphenolic coupling products is observed whereas, with the latter, this process is sterically inhibited. The value of flash photolysis as a probe for studying antioxidant activity is discussed. 相似文献