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91.
Gaetano Guerra Christophe Daniel Paola Rizzo Oreste Tarallo 《Journal of Polymer Science.Polymer Physics》2012,50(5):305-322
Polymeric “cocrystalline forms,” that is, structures were a polymeric host and a low‐molecular‐mass guest are cocrystallized, were early recognized, and in many cases also well characterized by X‐ray diffraction studies. However, only in the last two decades cocrystalline forms have received attention in material science, due to the ability (of few of them) to maintain an ordered polymer host structure even after guest removal, thus leading to the formation of “nanoporous‐crystalline forms,” for which many applications in the fields of molecular separation and sensors have been proposed. Moreover, in the last decade, an accurate control of the orientation of the polymer cocrystalline phases has been achieved, thus leading to a control of the orientation of the guest molecules, not only in the crystalline phase but also in macroscopic films. In addition, on the basis of this orientation control, in the last few years, cocrystalline films where active molecules are present as guests of polymer cocrystalline phases have been proposed for optical, magnetic and electric applications. In the last few years, it has been also discovered that polymer cocrystallization, when induced by nonracemic guest molecules, can produce stable chiral optical films. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
92.
Dr. Elena Ghedini Dr. Valentina Nichele Dr. Michela Signoretto Dr. Giuseppina Cerrato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(34):10653-10660
A series of titanium oxides was prepared by using a surfactant‐template method (STM) and used as a carrier for the sustained release of ibuprofen, which was chosen as a model drug. This STM provides an efficient route to TiO2 matrices with both high surface area (when compared with those that were obtained by using traditional synthetic approaches) and well‐defined mesoporous textures. Some parameters of the synthetic procedure were varied: pH value, surfactant, and thermal treatment. The physicochemical nature of the surface carriers were investigated by means of N2‐physisorption measurements and FTIR spectroscopy. The effect of the amount of drug on the release kinetics was also investigated. The drug delivery was evaluated in vitro in four different physiological solutions (that simulated the gastrointestinal tract) to analyze the behavior of the TiO2‐based systems if they were to be formulated as oral DDSs. Our optimized approach is a good alternative to the classical methods that are used to prepare efficient TiO2‐based drug‐delivery systems. 相似文献
93.
The light-enhanced NO<sub>2</sub> sensing properties of porous silicon gas sensors at room temperature
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The NO2 gas sensing behavior of porous silicon(PS) is studied at room temperature with and without ultraviolet(UV) light radiation.The PS layer is fabricated by electrochemical etching in an HF-based solution on a p +-type silicon substrate.Then,Pt electrodes are deposited on the surface of the PS to obtain the PS gas sensor.The NO2 sensing properties of the PS with different porosities are investigated under UV light radiation at room temperature.The measurement results show that the PS gas sensor has a much higher response sensitivity and faster response-recovery characteristics than NO2 under the illumination.The sensitivity of the PS sample with the largest porosity to 1 ppm NO2 is 9.9 with UV light radiation,while it is 2.4 without UV light radiation.We find that the ability to absorb UV light is enhanced with the increase in porosity.The PS sample with the highest porosity has a larger change than the other samples.Therefore,the effect of UV radiation on the NO2 sensing properties of PS is closely related to the porosity. 相似文献
94.
95.
Sequestration of carbon dioxide in geological formations is an alternative way of managing extra carbon. Although there are
a number of mathematical modeling studies related to this subject, experimental studies are limited and most studies focus
on injection into sandstone reservoirs as opposed to carbonate ones. This study describes a fully coupled geochemical compositional
equation-of-state compositional simulator (STARS) for the simulation of CO2 storage in saline aquifers. STARS models physical phenomena including (1) thermodynamics of sub- and supercritical CO2, and PVT properties of mixtures of CO2 with other fluids, including (saline) water; (2) fluid mechanics of single and multiphase flow when CO2 is injected into aquifers; (3) coupled hydrochemical effects due to interactions between CO2, reservoir fluids, and primary mineral assemblages; and (4) coupled hydromechanical effects, such as porosity and permeability
change due to the aforementioned blocking of pores by carbonate particles and increased fluid pressures from CO2 injection. Matching computerized tomography monitored laboratory experiments showed the uses of the simulation model. In
the simulations dissolution and deposition of calcite as well as adsorption of CO2 that showed the migration of CO2 and the dissociation of CO2 into HCO3 and its subsequent conversion into carbonate minerals were considered. It was observed that solubility and hydrodynamic storage
of CO2 is larger compared to mineral trapping. 相似文献
96.
The theory of long-term damage of homogeneous materials is generalized to particulate composite materials. The damage of the
composite components is modeled by randomly dispersed micropores. The damage criterion for a microvolume is characterized
by its stress-rupture strength. It is determined by the dependence of the time to brittle failure on the difference between
the equivalent stress and its limit, which is the tensile strength, according to the Huber-Mises criterion, and assumed to
be a random function of coordinates. An equation of damage (porosity) balance in the composite components at an arbitrary
time is formulated. Algorithms of calculating the time dependence of microdamage and macrostresses or macrostrains are developed
and corresponding curves are plotted in the case of limited microdurability
Translated from Prikladnaya Mekhanika, Vol. 44, No. 10, pp. 3–12, October 2008. 相似文献
97.
柠檬酸色谱分离的动力学模拟 总被引:3,自引:0,他引:3
报道一种在考虑柱床空隙率变化的条件下变温色谱动力学研究和参数测定的方法.以柠檬酸的提纯分离为实验例子,在分析柱上测定各模型参数,用这些热力学参数加入到平衡分散模型中,模拟在大型生产柱上的动力学行为,取得了非常满意的结果. 相似文献
98.
Peculiarities of carbonization of two styrene/divinylbenzene precursors (one sulfonated, another aminated and phosphorylated)
have been investigated by thermogravimetry and differential thermal analysis. It was shown that phosphorus compounds incorporate
into carbon structure and cause delayed carbonization. Porous structure and surface properties of synthetic carbons have been
investigated by standard (BET, αs method, DA) and advanced (AED, PSD, regularization) methods from benzene and water adsorption isotherms. It was shown that
phosphorus-containing carbon is less microporous and shows highly hydrophilic surface.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
99.
碱溶法制备高孔隙度多孔微球 总被引:2,自引:0,他引:2
提出并研究了以碱溶侵蚀提高多孔硅球孔隙度的新方法,研究了碱液浓度、处理温度、反应时间与洗除量的关系。结果表明,随着NaOH浓度的提高,不仅洗除量加大,而且硅胶的溶解速度亦少许增大,其主要原因是由于某些孔结构的塌陷导致了细屑的脱除。温度升高和处理时间延长会导致洗除量增大。随着洗除量的增加,硅胶的比孔容呈线性增大,但其外观仍为均匀的球形,且直径亦未见明显变化。选用粒径4~5 μm、孔径8 nm、比孔容1.4 cm3/g的多孔硅胶,采用1.25 mol/L NaOH水溶液、室温(25 ℃)处理3.0 h,制备了粒径4~5 μm、孔径14 nm、比孔容3.2 cm3/g的高孔隙度多孔硅胶,其孔隙度从75%增加到88%。 相似文献
100.
SiCp/Y112铝基复合材料制备工艺及性能 总被引:2,自引:0,他引:2
3种不同铸造工艺条件下铝基复合材料的微观组织,并对其硬度进行了测定.研究表明:与全液态铸造法和半固态铸造法相比,搅熔铸造制备的SiCp/Y112铝基复合材料,其增强相SiC颗粒分布均匀,气孔率较少.是一种较理想的金属基复合材料制备工艺.未增强的Y112基体铝合金的维氏硬度高于其半固态坯料的维氏硬度;而SiCp/Y112铝基复合材料的维氏硬度明显高于基体的维氏硬度,并随着SiC颗粒的体积分数的增加其复合材料的维氏硬度不断提高. 相似文献