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排序方式: 共有396条查询结果,搜索用时 15 毫秒
1.
Bera L.K. Ray S.K. Mukhopadhyay M. Nayak D.K. Usami N. Shiraki Y. Maiti C.K. 《Electron Device Letters, IEEE》1998,19(8):273-275
Growth of ultrathin (<100 Å) oxynitride on strained-Si using microwave N2O and NH3 plasma is reported. X-ray photoelectron spectroscopy (XPS) results indicate a nitrogen-rich layer at the strained-Si/SiO2 interface. The electrical properties of oxynitrides have been characterized using a metal-insulator-semiconductor (MIS) structure. A moderately low value of insulator charge density (6.1×1010 cm-2) has been obtained for NH3 plasma treated N2O oxide sample. Nitrided oxide shows a larger breakdown voltage and an improved charge trapping properties under Fowler-Nordheim (F-N) constant current stress 相似文献
2.
From flash photolysis data of benzil and 2,2′-dichlorobenzil, the role of conformeric triplets in the formation of hydrogen
adduct radicals has been discussed. The planar relaxed triplet absorbing at 470 nm is less efficient in forming a hydrogen
adduct radical as compared to its puckered conformeric partner. Among the hydrogen donors, triethyl amine and isopropanol,
the former is more efficient in converting puckered triplets and less efficient in the case of planar conformers. Absorptions
of radicals and radical anions of 2,2′-dichlorobenzil appear at 355 nm and 460 nm respectively. These are blue-shifted as
compared to those of the parent compound benzil appearing at 370 nm and 540 nm, respectively. This blue-shift has been discussed
in terms of steric hindrance due to ortho-substitution. 相似文献
3.
The first enantiospecific approach to garsubellin A and related phloroglucin natural product nemorosone, of contemporary interest from (−)-α-pinene, has been delineated. Through a series of stereospecific operations, the requisite stereochemistry of the prenyl groups has been secured. Kende cyclization has been employed as the key step to construct the functionalized bicyclo[3.3.1]nonane core. 相似文献
4.
Silver-palladium nanodispersions in silicate matrices: highly uniform, stable, bimetallic structures
Ag-Pd nanobimetallic colloidal particles are prepared in a single step by a chemical reduction method. Organically modified aminosilicate is used as a supporting matrix as well as a stabilizing agent, to obtain very uniform, well-distributed bimetallic particles. These nanoparticles are found to be stable for several months in both the solid and the liquid phases. The structure of the bimetallic particles has been followed by X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy. The distribution and the particle size are determined by transmission electron microscope and X-ray diffraction studies. Polymerization and condensation of the support silicate material have been confirmed by Fourier transform infrared spectroscopy. 相似文献
5.
Reaction of Mo(2)Cl(4)(dppm)(2) (dppm = bis(diphenylphosphino)methane) with 6 equiv of [n-Bu(4)N][CN] or [Et(4)N][CN] in dichloromethane yields [n-Bu(4)N](2)[Mo(2)(CN)(6)(dppm)(2)] (1) and [Et(4)N](2)[Mo(2)(CN)(6)(dppm)(2)] (2), respectively. The corresponding one- and two-electron oxidation products [n-Bu(4)N][Mo(2)(CN)(6)(dppm)(2)] (3) and Mo(2)(CN)(6)(dppm)(2) (4)were prepared by reactions of 1 with the oxidant NOBF(4). Single-crystal X-ray structures of 2.2CH(3)CN, 3.2CH(3)CN.2H(2)O, and 4.2CH(3)NO(2) were performed, and the results confirmed that all three complexes contain identical ligand sets with trans dppm ligands bisecting the Mo(2)(mu-CN)(2)(CN)(4) equatorial plane. The binding of the bridging cyanide ligands is affected by the oxidation state of the dimolybdenum core as evidenced by an increase in side-on pi-bonding overlap of the mu-CN in going from 1 to 4. The greater extent of pi-donation into Mo orbitals is accompanied by a lengthening of the Mo-Mo distance (2.736(1) A in Mo(2)(II,II) (2), 2.830(1) A in Mo(2)(II,III) (3), and 2.936(1) A in Mo(2)(III,III) (4)). A computational study of the closed-shell members of this homologous series, [Mo(2)(CN)(6)(dppm)(2)](n)() (n = 2-, 0), indicates that the more pronounced side-on pi-donation evident in the X-ray structure of 4 leads to significant destabilization of the delta orbital and marginal stabilization of the delta() orbitals with respect to nearly degenerate delta and delta orbitals in the parent compound, 2. The loss of delta contributions combined with the reduced orbital overlap due to higher charges on molybdenum centers in oxidized complexes 3 and 4 is responsible for the observed increase in the length of the Mo-Mo bond. 相似文献
6.
Ashutosh Kumar Singh Asish Bera Hafizur Rahaman Jimson Mathew Dhiraj K.Pradhan 《中国电子科技》2009,7(4):336-342
An error tolerant hardware efficient verylarge scale integration (VLSI) architecture for bitparallel systolic multiplication over dual base, which canbe pipelined, is presented. Since this architecture has thefeatures of regularity, modularity and unidirectionaldata flow, this structure is well suited to VLSIimplementations. The length of the largest delay pathand area of this architecture are less compared to the bitparallel systolic multiplication architectures reportedearlier. The architecture is implemented using Austria Micro System's 0.35 μm CMOS (complementary metaloxide semiconductor) technology. This architecture canalso operate over both the dual-base and polynomialbase. 相似文献
7.
Singh N. Agarwal A. Bera L.K. Liow T.Y. Yang R. Rustagi S.C. Tung C.H. Kumar R. Lo G.Q. Balasubramanian N. Kwong D.-L. 《Electron Device Letters, IEEE》2006,27(5):383-386
This paper demonstrates gate-all-around (GAA) n- and p-FETs on a silicon-on-insulator with /spl les/ 5-nm-diameter laterally formed Si nanowire channel. Alternating phase shift mask lithography and self-limiting oxidation techniques were utilized to form 140- to 1000-nm-long nanowires, followed by FET fabrication. The devices exhibit excellent electrostatic control, e.g., near ideal subthreshold slope (/spl sim/ 63 mV/dec), low drain-induced barrier lowering (/spl sim/ 10 mV/V), and with I/sub ON//I/sub OFF/ ratio of /spl sim/10/sup 6/. High drive currents of /spl sim/ 1.5 and /spl sim/1.0 mA//spl mu/m were achieved for 180-nm-long nand p-FETs, respectively. It is verified that the threshold voltage of GAA FETs is independent of substrate bias due to the complete electrostatic shielding of the channel body. 相似文献
8.
Shailendra Singh Subhash Chandra Bera Punam Pradeep Kumar Dhaval Pujara 《Radioelectronics and Communications Systems》2017,60(11):479-484
In this paper, formulae to determine the lowest order and other higher order spurious frequencies that coincide with desired output signal frequencies of mixers have been derived. The proposed formulae give general expressions that are suitable for any order of heterodyne mixing. The formulae have been verified using a suitable example and compared with the simulation results obtained through the radio frequency simulation software of Advanced Design System. The formulae directly reveal the order of the troublesome spurious frequencies that the designers would encounter in heterodyne systems. In comparison with these direct formulae, the results of existing spurious analysis software are based on the maximum order of simulation carried out. Based on these simulations, the coinciding spurious components have to be manually sorted out. Proposed formulae are quick tools used by the microwave system and circuit designers for choosing and finalizing heterodyne frequencies in their designs without the need for any simulations. 相似文献
9.
Parnajyoti Karmakar Sumon Ray Debabrata Nandi Arup Mandal Subala Mondal Subhasis Mallick Biplab K. Bera Alak K. Ghosh 《Journal of solution chemistry》2013,42(2):441-458
The kinetics of the substitution reactions of [Pt(dach)(H2O)2]2+ and [Pt(en)(H2O)2]2+ (where ‘dach’ and ‘en’ are cis-1,2-diaminocyclohexane and ethylenediamine, respectively) with excess N,N′-diethylthiourea have been studied in aqueous solution by UV–Vis spectrophotometry. The effect of different N–N spectator ligands on the reactivity of platinum(II) complexes was investigated by studying the water lability of the reactant complexes. The kinetic study has been substantiated by product isolation, IR, NMR and ESI-MS spectral analysis and DFT calculations. The reactions follow normal square-planar substitution mainly in an associative way. Rate parameters have been evaluated under different conditions. The substitution rates of the complexes studied can be tuned through the nature of the N–N chelates, which is important in the development of new active compounds for cancer therapy. 相似文献
10.
AgBArF displays remarkable ‘on-water’ activity for catalytic hydration of terminal alkynes although it is ineffective in common organic solvents. Liquid alkynes do not require additive or co-solvent whereas a small amount of ethyl acetate triggers quantitative conversions for solid alkynes. 相似文献