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471.
Potential Analysis - This note studies the asymptotic behavior of global solutions to the fourth-order Schrödinger equation $$ idot u+{Delta}^{2} u-F(x,u)=0 . $$ Indeed, for both cases,... 相似文献
472.
Bo Lu Chao Song Jie Liu Dr. Tarek Trabelsi Prof. Dr. Joseph S. Francisco Dr. Lina Wang Prof. Dr. Xiaoqing Zeng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(13):2817-2820
Two atmospherically relevant dihalogenated methylperoxy radicals CHX2OO. (X=F and Cl) have been generated through O2-oxidation of the corresponding alkyl radicals CHX2. in the gas phase. The IR spectroscopic characterization of both radicals in cryogenic Ar- and N2-matrices (15 K) is supported by 18O-labeling and ab initio calculations at the UCCSD(T)/aug-cc-pVTZ level. Upon 266 nm laser irradiation, both radicals decompose mainly by releasing hydroxyl radicals (→HO.+X2CO) via the intermediacy of intriguing α-hydroperoxyalkyl radicals (.CX2OOH), implying that the photooxidation of dihalogenated hydrocarbons might serve as important sources of HO. radicals in the atmosphere. 相似文献
473.
Wireless Networks - Toward the growing number of the transport safety applications offered by VANET, a large amount of messages need to be efficiently disseminated between connected vehicles. The... 相似文献
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Alaa S. Abd-El-Aziz Erin K. Todd Rawda M. Okasha Tarek H. Afifi 《Macromolecular Symposia》2003,196(1):89-99
The synthesis of cationic organoiron polymers with azobenzene moieties in their side chains has been accomplished via nucleophilic aromatic substitution and ring-opening metathesis polymerization (ROMP) reactions. Polyaromatic ethers and thioethers with azobenzene moieties in their side chains were functionalized with different chromophores to yield yellow-, orange- and red-colored polymers. Polynorbornenes with azobenzene-containing side chains were isolated following ROMP of their monomeric analogs. All of the organoiron polymers were soluble in polar organic solvents and underwent reversible electrochemical reduction processes. Photobleaching of the azobenzene-containing polymers was achieved in the presence of hydrogen peroxide. The metallated polymers had glass transition temperatures approximately 50 to 80°C higher than their organic analogs. 相似文献
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Recently, solar energy emerged as a feasible supplement to battery power for wireless sensor networks (WSNs) which are expected to operate for long periods. Since solar energy can be harvested periodically and permanently, solar‐powered WSNs can use the energy more efficiently for various network‐wide performances than traditional battery‐based WSNs of which aim is mostly to minimize the energy consumption for extending the network lifetime. However, using solar power in WSNs requires a different energy management from battery‐based WSNs since solar power is a highly varying energy supply. Therefore, firstly we describe a time‐slot‐based energy allocation scheme to use the solar energy optimally, based on expectation model for harvested solar energy. Then, we propose a flow‐control algorithm to maximize the amount of data collected by the network, which cooperates with our energy allocation scheme. Our algorithms run on each node in a distributed manner using only local information of its neighbors, which is a suitable approach for scalable WSNs. We implement indoor and outdoor testbeds of solar‐powered WSN and demonstrate the efficiency of our approaches on them. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
478.
Alaa S. Abd-El-Aziz Rawda M. Okasha Erin K. Todd Tarek H. Afifi Patrick O. Shipman K. Michelle D. Copping 《Macromolecular Symposia》2004,209(1):185-194
The synthesis of cationic cyclopentadienyliron-containing polymers with pendent azobenzene chromophores was accomplished via metal-mediated nucleophilic aromatic substitution reactions. All of the desired polymers were isolated as vibrantly coloured materials and displayed excellent solubility in polar aprotic solvents. Cationic and neutral cyclopentadienyliron polymers incorporating azo dyes in the backbone were also prepared. Reactions of azo dyes with dichlorobenzene complexes allowed for the isolation of cationic cyclopentdienyliron (CpFe+) complexes with azo dye chromophores. These complexes were then reacted with 1,1′-ferrocenedicarbonyl chloride to produce the trimetallic monomers with terminal chloro groups. These monomers contained two pendent CpFe+ cations and a neutral iron moiety in the backbone. Nucleophilic substitution reactions of these monomers with oxygen and sulfur containing dinucleophiles gave rise to a new class of polymeric materials. The pendent CpFe+ moieties could also be cleaved from the polymer backbones using photolysis to afford novel ferrocene based polymers. The UV-vis spectra of the organoiron monomers and polymers display similar wavelength maxima however incorporating azobenzene chromophores with electron-withdrawing substituent into the polymer chains resulted in bathochromic shifts of the λmax values. 相似文献
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Organoiron polynorbornene containing arylazo or hetarylazo dye chromophores has been prepared via ring opening metathesis polymerization using Grubbs' catalyst. The obtained polymers were isolated as brightly colored materials and displayed good solubility in polar organic solvents. The colors of these polymers were affected by the nature of the incorporated azo chromophores. Thermogravimetric analysis of these materials showed that the cleavage of the cyclopentadienyliron (CpFe+) moieties was between 225 and 231 °C, while the degradation of the polymer backbones occurred between 400 and 450 °C. UV-vis studies in DMF showed that the organoiron polymers containing arylazo dyes exhibit wavelength maxima around 425 nm. However, the replacement of these arylazo moieties with hetarylazo dyes displayed substantial bathochromic shifts in the λmax values (≈ 511 nm). 相似文献