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41.
S. J. Pearton W. S. Hobson M. Geva U. K. Charkrabarti E. Lane A. P. Perley 《Plasma Chemistry and Plasma Processing》1991,11(2):295-310
The reactive ion etching of GaAs, InP, InGaAs, and InAlAs in CF3Br/Ar discharges was investigated as a function of both plasma power density (0.56-1.3 W - cm–2) and total pressure (10-40 mTorr) The etch rate of GaAs in 19CF3Br:1Ar discharges at 10 m Torr increases linearly with power density, from 600 Å min–1 at 0.56 W · cm–2, to 1550 Å · min at 1.3 W · cm–2. The in-based materials show linear increases in etch rates only for power densities above – 1.0 W · cm–2. These etch rates are comparable to those obtained with CCI2F2:O2 mixtures under the same conditions. Smooth surface morphologies and vertical sidewalls are obtained over a wide range of plasma parameters. Reductions in the near-surface carrier concentration in n-type GaAs are evident for etching with power densities of >0.8 W cm–2, due to the introduction of deep level trapping centers. At 1.3 W· cm–2, the Schottky barrier height of TiPtAu contacts on GaAs is reduced from 0.74 to 0.53 eV as a result of this damage, and the photoluminescent intensity from the material is degraded. Alter RIE, we detect the presence of both F and Br on the surface of all of the semiconductors. This contamination is worse than with CCl2F2-based mixtures. High-power etching with CF3Br/Ar together with Al-containing electrodes can lead to the presence of a substantial layer of aluminum oxide on the samples if the moisture content in the reactor is appreciable. 相似文献
42.
A. M. Wrobel B. Lamontagne M. R. Wertheimer 《Plasma Chemistry and Plasma Processing》1988,8(3):315-329
We have investigated O2/CF4 plasma etching of five commercial polymers: polyimide, polyamide, polyethylene terephthalate, polycarbonate and cured epoxy resin. A new large-area microwave plasma apparatus has been used in this work, but the same apparatus can also be used as a capacitively coupled radiofrequency (13.56 MHz) discharge reactor. The effect of operating parameters such as pressure, etchant gas composition, excitation frequency and sample temperature upon etch kinetics has been examined. We have observed distinct maxima in the etch rate as functions of pressure and CF4 concentration. Activation, energies evaluated from the Arrhenius plots fall in the range 0.04-0.2 eV, in agreement with data in the literature. Dry etch susceptibility of a given polymer correlates strongly with the degree of unsaturation in the polymer's structure 相似文献
43.
44.
The objective of this study was to examine some fundamental factors involved in the design and construction of the anode magnetron dc glow discharge processes as well as its performance in plasma cleaning and polymerization. Those advantages of anode magnetron include the capability of the magnetron to operate at low pressure, as well as decreasing the thickness of cathode dark space, i.e., the negative glow which contains a higher concentration of ions and active species was more closely to the cathode surface, which makes the plasma surface cleaning and polymerization an effective and uniform processes. The deposition rate at a given discharge power is increased by the presence of anode magnetrons, and is also much higher relative to rf and af. The refractive index of dc plasma film at a given polymer thickness (such as TMS, 70 nm, RI: 2.4) is higher than rf, af, and cascade arc plasma (RI: 1.6–1.7). 相似文献
45.
《Arabian Journal of Chemistry》2020,13(2):4082-4091
In present study, an investigation was carried out to develop and validate an analytical method for the selective extraction and determination of griseofulvin (GSF) from plasma samples. For this purpose, a rational approach was made to synthesize and characterize the surface molecularly imprinted polymers (SMIPs). The SMIPs were utilized as solid phase extraction (SPE) sorbents. The SMIPs were prepared by using GSF as template molecule on the surface of modified silica particles through a non-covalent technique. The particles demonstrated high adsorption capacity (119.1 µg/mL), fast adsorption equilibrium time (30 min) and good recognition selectivity for the template drug. The scanning electron microscopy and infrared spectroscopy were used to explain the structural and morphological characteristics of the SMIPs and surface non-imprinted polymers. The SPE method was combined with HPLC for plasma analysis. The method validation results demonstrated that the established method possessed good linearity for GSF ranging from 0.1 to 50 µg/mL (R2 = 0.997). The limit of detection for this method was 0.02 µg/mL for rat plasma samples. The recoveries of GSF from spiked plasma samples were (90.7–97.7%) and relative standard deviations were (0.9–4.5%). Moreover, the SMIPs as selective SPE sorbent can be reused more than 8 times which is a clear advantage over commercial SPE sorbents. Finally, the usefulness of the proposed strategy was assessed by extraction and detection of GSF in real rat plasma samples. 相似文献
46.
重点介绍了 HL-2M 装置的运行技术和初步的等离子体控制实验结果,包括等离子体放电方案设计、
线圈电流控制、击穿阶段零场匹配和等离子体电流以及位移的控制。为了降低放电运行风险,HL-2M 装置初始放
电采用了简化的放电方案,通过整定 PID 参数实现了线圈电流控制,在击穿阶段获得了 10V 以上的环电压和较大
范围的零场区域,成功实现等离子体击穿。最后,投入了等离子体电流和水平位移反馈控制算法,成功将等离子
体放电脉宽提升至 200ms 以上,且维持 Ip≥100kA 的时间超过了 100ms,上述结果表明 HL-2M 装置运行控制技术
得到了初步的检验。 相似文献
47.
以液体中光击穿所激发声场为研究对象,在等离子体椭球模型的基础上,为方便理论计算,简化等离子体椭球模型,提出了等离子体椭圆盘模型,对光击穿所激发声场进行了理论研究.得到了等离子体椭圆盘辐射声场的声压规律,并利用椭圆坐标变换,依据马修函数特性和模态的正交性,求得了等离子体椭圆盘振动位移的解析表达式. 相似文献
48.
钛酸钾晶须通常是直径和长度在微米量级的无机晶须 ,可用K2 O·nTiO2 表示其组成 ,n =1,2 ,4 ,6 ,8,[1] .六钛酸钾晶须具有耐高温、耐腐蚀、纤维拉伸强度高、导热系数小、红外反射率高 ,硬度低的特点 .在民用及工业方面有很多应用 .如催化剂载体、离子吸附交换材料、高温过滤器、绝热材料、耐摩擦材料等[2~ 5] .钛酸钾纳米线的合成尚未见报道 .我们在用电弧产生的N2 等离子体热解焦油时 ,生成了一种直径 9~ 2 0nm长约几百纳米线 .X射线能谱定量分析表明这种纳米线化学组成为K2 Ti8O15,是一种新的非化学计量化合物 .试验装… 相似文献
49.
Stephanie Hansen G.S.J. Armstrong S. Bastiani-Ceccotti C. Bowen H.-K. Chung J.P. Colgan F. de Dortan C.J. Fontes F. Gilleron J.-R. Marquès R. Piron O. Peyrusse M. Poirier Yu. Ralchenko A. Sasaki E. Stambulchik F. Thais 《High Energy Density Physics》2013,9(3):523-527
Collisional-radiative atomic models are widely used to help diagnose experimental plasma conditions through fitting and interpreting measured spectra. Here we present the results of a code comparison in which a variety of models determined plasma temperatures and densities by finding the best fit to an experimental L-shell Kr spectrum from a well characterized, but not benchmarked, laser plasma. While variations in diagnostic strategies and qualities of fit were significant, the results generally confirmed the typically quoted uncertainties for such diagnostics of ±20% in electron temperature and factors of about two in density. The comparison also highlighted some model features important for spectroscopic diagnostics: fine structure was required to match line positions and relative intensities within each charge state and for density diagnostics based on emission from metastable states; an extensive configuration set was required to fit the wings of satellite features and to reliably diagnose the temperature through the inferred charge state distribution; and the inclusion of self-consistent opacity effects was an important factor in the quality of the fit. 相似文献
50.
Selenium has been identified as an essential dietary trace e1ementQ)which is a component of glutathione peroxidase (GSH-Px)(2)and a cytochrome C-like protein(3), The enzyme,the four subunits of which each contain one atom of selenium in the form of selenocysteine, the selenium containing active centre being amenable to chemical modification, catalyses the reduction of H,O,and organic hydroperoxides to water.In this way GSH-Px plays an important role in the protection of the cell from oxidative stresses such as the superoxide anion,organic hydroperoxides and H2O2 相似文献