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1.
Axel Fischer Peter G. Jones Ion Neda Reinhard Schmutzler Igor V. Shevchenko 《无机化学与普通化学杂志》1994,620(5):908-913
Synthesis and Molecular Structure of new Ring Systems from 1,1,3,3-Tetrachloro-1,3-diphosphapropane 1,1,3,3-Tetrachloro-1,3-diphosphapropane 1 reacts in two different ways to form new heterocycles. Partial oxidation of 1 with tetrachloroorthobenzoquinone furnishes the methylene-bridged λ3P, λ5P species 3 . Subsequent reactions with di- and triethylamine lead to the condensed ring system 6 with the P?C bonds connected to a central four-membered ring. Compound 6 displays crystallographic inversion symmetry, a short transannular P? P distance and an extremely distorted tetrahedral coordination geometry at the four-membered ring phosphorus atoms. 1 reacts with 7 to give the heterocycle 8 with a central eight-membered ring involving four phosphorus atoms. The eight – membered ring shows a ?bent”? crown conformation, the condensed five – membered rings display envelope conformation. 相似文献
2.
Ion Neda Carsten Melnicky Alexander Vollbrecht Axel Fischer Peter G. Jones Reinhard Schmutzler 《无机化学与普通化学杂志》1996,622(6):1047-1059
The reaction of methylisatoic acid anhydride 1 with benzylamines led to the N-benzyl-N′-methylanthranilamide derivatives 2 – 4 . Their reaction with phosphorus trichloride furnished the 2-chloro-1-halobenzyl/benzyl-3-methyl-4(1 H)-1,3,2-benzodiazaphosphorin-4-ones 5 – 7 which, upon reaction with bis-(2-chloroethyl)ammonium chloride/triethylamine, were converted into the P-bis-(2-chloroethyl)amino-1-halobenzyl/benzyl-3-methyl-4(1 H)-1,3,2-benzodiazaphosphorin-4-ones 8 – 10 and 12 . With 2-chloroethylammonium chloride/triethyl-amine the P? NHCH2CH2Cl-substituted compound 11 was obtained from the PIIICl-species 6 . The reaction of 8 – 10 and 12 with hexafluoroacetone (HFA) took an unusual course: apart from the oxidative addition of HFA and formation of the perfluoropinacolyl ring system, one of the two CH2CH2Cl groups was found to alkylate the CH3N atom with formation of a five-membered (diazaphospholane) ring in the tricyclic phosphoranes 13 – 16 . The reaction of 11 with HFA also produced a spirophosphorane 17 which involved a λ5-oxazaphosphetidine ring system. In the reaction of 8, 10 and 12 with tetrachloro-o-benzoquinone, an oxidative addition reaction with concomitant N-alkylation and formation of the tricyclic phosphoranes 18 – 20 was found to take place. Single crystal X-ray structure determinations are described for the phosphoranes 13, 14 and 16 , and for the precursor compound 9 . The following features are common to the isostructural compounds 13 and 16 and the diethyl ether hemisolvate of 14 : the (λ5)-spiro phosphorus atom lies out of the plane of the other atoms of the rings to which it is common, and the dioxaphospholane rings display a twist conformation. In the λ3P-compound 9 the phosphorus atom also lies out of the plane of the other ring atoms. 相似文献
3.
Fateme Salehi Mohammad‐Hassan Majidi Naaser Neda 《International Journal of Communication Systems》2018,31(12)
The abundant benefits of Orthogonal Frequency‐Division Multiplexing and its high flexibility have resulted in its widespread applications in many telecommunication standards. One important parameter for improving wireless system's efficiency is the accurate estimation of channel state information. In the literatures, many techniques have been studied in order to estimate the channel state information. Nowadays, the techniques based on intelligent algorithms such as genetic algorithm and particle swarm optimization (PSO) have attracted attention of researchers. With a very low pilot overhead, these techniques are able to estimate the channel frequency response properly only using the received signals. Unfortunately, each of these techniques suffers a common weakness: they have a slow convergence rate. In this paper, a new intelligent and different method has been presented for channel estimation using learning automata, entitled LA estimator, where the learning automata are search agents, and each pair is responsible for searching 1 complex coefficient of the channel frequency response. This method can achieve an accurate channel estimation with a moderate computational complexity in comparison with GA and PSO estimators. Furthermore, with higher convergence rate, our proposed method is capable of providing the same performance as GA and PSO. For a 2‐path fast fading channel, simulation results demonstrate the robustness of our proposed scheme according to the bit error rate and the mean square error. 相似文献
4.
Cationic Nanogels: Reduction‐Sensitive Dextran Nanogels Aimed for Intracellular Delivery of Antigens (Adv. Funct. Mater. 20/2015) 下载免费PDF全文
5.
Ali Reza Kazemizadeh Nahid Shajari Reza Shapouri Neda Adibpour Reza Teimuri‐Mofrad Parisa Dinmohammadi 《应用有机金属化学》2016,30(3):148-153
A four‐component reaction between aromatic carboxylic acids, (N‐isocyanimino)triphenylphosphorane, ferrocenecarbaldehyde and dibenzylamine is reported. This approach is an efficient, simple and high‐yield procedure for the synthesis of 1,3,4‐oxadiazole derivatives containing a ferrocene unit. The antimicrobial activities of the products were investigated against Staphylococcus aureus and Pseudomonas aeruginosa in in vitro and in vivo assays. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
Hamid Reza Shaterian Asghar Hosseinian Majid Ghashang Fahimeh Khorami Neda Karimpoor 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2333-2338
An environmentally friendly procedure for the preparation of dihydropyrimidinone derivatives or their sulfur analogues under thermal solvent-free conditions in the presence of aluminium hydrogen sulfate [Al(HSO4)3] and alumina sulfuric acid (Al2O3-SO3H) as heterogeneous catalysts was developed. 相似文献
7.
Neda Seyedi 《Transition Metal Chemistry》2013,38(1):93-103
In this investigation, glycerol and [Fe(III)(salen)]Cl as a green catalyst system were used in multicomponent reactions for the synthesis of bis(indolyl)methanes, 3,4-dihydropyrimidinones, and 1,4-dihydropyridines, respectively. Excellent product yields and short reaction times were achieved. 相似文献
8.
Mohd Muddassir Abdullah Alarifi Mohd Afzal Ahmad Alowais Naaser A. Y. Abduh 《无机化学与普通化学杂志》2020,646(14):1205-1211
This article outlines the magnetic features of a new six–coordinate high-spin cobalt(II) complex cis-[CoII(tmphen)2(NCS)2] ( 1 ) achieved via the reactions of cobalt(II) thiocyanate with 3,4,7,8-tetramethyl-1,10-phenanthroline. The complex 1 was thoroughly characterized by different analytical and spectroscopic techniques and further confirmed by single X-ray crystal diffraction pattern. Complex 1 is a neutral molecule and adopt highly distorted six-coordinate CoN6 octahedral coordination sphere surrounded by two thiocyanate N atoms in cis locations and the equatorial plane is occupied by two imine N atoms from the two tmphen ligand while the remaining two imine N atoms reside in the axial positions. Magnetic susceptibility data of complex 1 revealed that the χΜT values decrease significantly to a value of 1.49 cm3 · K · mol–1 at 2.0 K on decreasing temperatures below 100 K, mainly ascribed to the significant spin–orbit coupling (SOC) of six-coordinate CoII ions. Furthermore, a field-dependence measurement was performed at 2 K, which shows a positive curvature up to 27 kOe, while it becomes linear up to 2.01 NμB, which authenticated the fact that only the lowest Kramers doublet of ground state is appreciably populated. 相似文献
9.
Majid M. Heravi Neda Zamani Ahari Hossein A. Oskooie Mitra Ghassemzadeh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1701-1712
Abstract Mild and efficient S-methylation of thiols and o-methylation of phenols and naphthols occurs with dimethyl sulfate (DMS) supported on basic alumina under microwave irradiation in solventless system. 相似文献
10.
Sharma PK Reilly MJ Bhatia SK Sakhitab N Archambault JD Bhatia SR 《Colloids and surfaces. B, Biointerfaces》2008,64(2):229-235
Pluronic F127, a triblock copolymer of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), has generated considerable interest as a drug delivery vehicle due to its ability to gel at physiological temperatures. This work examines the gelation behavior of Pluronic F127 in the presence of a series of hydrophobic pharmaceuticals, to determine whether there is any correlation between gelation and physicochemical parameters of drug solutes. The study includes the local anesthetics dibucaine, lidocaine, and tetracaine; the pharmaceutical additives methyl paraben, ethyl paraben, and propyl paraben; the anti-cancer agents paclitaxel and baccatin III; and the anti-inflammatory agent sulindac. The results indicate that the presence of local anesthetics and pharmaceutical additives allows F127 solutions to form gels at lower copolymer concentrations; local anesthetics and pharmaceutical additives also shift gelation down to a lower gelation temperature. This behavior is strongly dependent on drug solubility; poorly soluble drugs (paclitaxel, baccatin III, sulindac) do not change the lower gelation temperature or minimum F127 concentration for gelation. An equation relating the decrease in gelation temperature to drug solubility is presented, and the equation fits the data well. The results have significant positive implications on the toxicity and economic issues related to use of Pluronic F127 in drug delivery. 相似文献