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71.
Aiju Zhang Zhihong Li Zicheng Li Yumei Zhu 《Journal of Sol-Gel Science and Technology》2009,49(1):6-11
SiO2–Al2O3–Na2O glass coated cubic boron nitride (cBN) abrasive particles were prepared by sol–gel technique. The results indicated that
SiO2–Al2O3–Na2O glass was excellent material for oxidation protection of cBN abrasive grains because coefficient of thermal expansion of
this glass closely matched that of cBN materials. The single particle compressive strength and impact toughness of this glass
coated cBN abrasive particles were significantly increased. For the application of glass coated cBN abrasives to vitrified
grinding wheels, it was evident that the glass coating provided high bonding strength between cBN abrasive grains and vitrified
bond system. 相似文献
72.
The principles of colloid and interface science underlie the successful formulation and manufacture of photographic products. The colour-forming components are usually delivered in colloidal form. Rapid and stable manufacture depends on the dynamic surface properties and the rheology of the coated fluids. 相似文献
73.
《Current Applied Physics》2018,18(8):946-951
Owing to the performance of the CdSe as an optoelectronic material used for the production of quantum dots, photosensors and wave traps we here, in this article, report the enhancements in structural and electrical properties that arises from the nanosandwiching of a 40 nm thick Yb film between two films of CdSe (CYbC-40). The CdSe films which were deposited onto glass, Yb and Au substrates are characterized by X-ray diffraction, temperature dependent electrical conductivity and impedance spectroscopy measurements in the frequency range of 10–1800 MHz. The analysis of the XRD patterns have shown that the glass/CdSe/Yb/CdSe films exhibit larger grain size and lower strain, defect density and lower stacking faults compared to the not sandwiched CdSe. In addition, it was observed that the Yb shifts the donor states of the n-type CdSe from 0.44 to 0.29 eV leading to a modification in the built in voltage of the material. On the other hand, the design of the energy band diagram has shown the ability of the formation of the Au/CYbC-40/Yb as Schottky (SB) and the Au/CYbC-40/Au as back to back Schottky barriers (BBSB). While the SB device show low band pass filter characteristics, the BBSB device performed as band stop filters. The BBSB device exhibited negative capacitance effects with filtering features that reveal a return loss of 42 dB at ∼1440 MHz. 相似文献
74.
采用电沉积法在镍合金表面制备钼镍镀层。研究钼镍镀层的硬度、磨损质量和摩擦系数、热膨胀等性能。分别用发射光谱法、能谱法、扫描电镜法和X衍射法等对钼镍镀层进行表征。在镍合金表面镀上一层钼镍镀层,可使其的硬度和耐磨性大幅度提高并减小磨擦系数,钼镍镀层的硬度为518 HV,比镍合金的硬度(300 HV)提高了72.67%;钼镍镀层的磨损质量是镍合金的磨损质量的1/1.94;镍合金和钼镍镀层的磨擦系数分别为0.640和0.559。镍合金的物理热膨胀曲线在100~120℃温度范围和570~640℃范围形成了2个峰,镍合金+钼镍镀层的物理热膨胀曲线在570~640℃范围形成了1个峰。在570~640℃范围可明显改善其热膨胀,镍合金+钼镍镀层的物理热膨胀曲线在570~640℃范围形成的峰远比镍合金的物理热膨胀曲线在570~640℃范围形成的峰小,可能是因为钼进入到镍的晶格中,抑制了镍在570~640℃范围发生晶格转变(bcc→fcc)所致。镍合金+钼镍镀层的物理热膨胀曲线在595~625℃范围形成的小峰,可能是由于MoNi_4和MoNi由半晶型结构转变为晶型结构所致。 相似文献
75.
This study explored the adsorption behavior of Cu2+ onto iron oxide coated eggshell powder (IOESP) from aqueous solution. The effect of various operational parameters such as pH, contact time, initial adsorbate concentration, surfactant, and temperature on adsorption of Cu2+ ions was investigated using batch adsorption experiments. The optimum pH for Cu2+ adsorption was found to be 6.0. Kinetics of adsorption was found to follow the pseudo-second-order rate equation. The suitability of Langmuir and Freundlich adsorption models to the equilibrium data was investigated. The adsorption was well described by the Freundlich isotherm model indicating the presence of heterogeneous sites for Cu2+ adsorption. The adsorption of Cu2+ was increased in the presence of anionic surfactant (SDS) while cationic surfactant (CTAB) shows no significant change in adsorption capacity. Thermodynamic parameters showed that the adsorption of Cu2+ onto IOESP was feasible, spontaneous, and exothermic. Regeneration studies were performed using HCl, HCOOH, EDTA, and NaOH as eluting agent for Cu2+ desorption from saturated IOESP and the maximum regeneration was observed with HCl. 相似文献
76.
Characterization of Microvascular-Based Self-healing Coatings 总被引:1,自引:1,他引:0
A protocol is described to assess self-healing of crack damage in a polymer coating deposited on a substrate containing a
microvascular network. The bio-inspired coating/substrate design delivers healing agent to cracks in the coating via a three-dimensional
microvascular network embedded in the substrate. Through capillary action, monomer flows from the network channels into the
crack plane where it is polymerized by a catalyst embedded in the coating. The healing efficiency of this materials system
is assessed by the recovery of coating fracture toughness in a four-point beam bending experiment. Healing results for the
microvascular networks are compared to data for a coating containing microencapsulated healing agents. A single crack in a
brittle epoxy coating is healed as many as seven times in the microvascular systems, whereas microcapsule-based healing occurs
for only one cycle. The ability to heal continuously with the microvascular networks is limited by the availability of catalyst
in the coating. 相似文献
77.
Molecular Dynamic Simulation on the Absorbing Process of Isolating and Coating of α-olefin Drag Reducing Polymer 下载免费PDF全文
The absorbing process in isolating and coating process of α-olefin drag reducing polymer was studied by molecular dynamic simulation method, on basis of coating theory of α-olefin drag reducing polymer particles with polyurethane as coating material. The distributions of sodium laurate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate on the surface of α-olefin drag reducing polymer particles were almost the same, but the bending degrees of them were obviously different. The bending degree of SLA molecules was greater than those of the other two surfactant molecules. Simulation results of absorbing and accu-mulating structure showed that, though hydrophobic properties of surfactant molecules were almost the same, water density around long chain sulfonate sodium was bigger than that around alkyl sulfate sodium. This property goes against useful absorbing and accumulating on the surface of α-olefin drag reducing polymer particles; simulation results of interactions of different surfactant and multiple hydroxyl compounds on surface of particles showed that, interactions of different surfactant and one kind of multiple hydroxyl compound were similar to those of one kind of surfactant and different multiple hydroxyl compounds. These two contrast types of interactions also exhibited the differences of absorbing distribution and closing degrees to surface of particles. The sequence of closing degrees was derived from sim-ulation; control step of addition polymerization interaction in coating process was absorbing mass transfer process, so the more closed to surface of particle the multiple hydroxyl com-pounds were, the easier interactions with isocyanate were. Simulation results represented the compatibility relationship between surfactant and multiple hydroxyl compounds. The isolating and coating processes of α-olefin drag reducing polymer were further understood on molecule and atom level through above simulation research, and based on the simulation, a referenced theoretical basis was provided for practical optimal selection and experimental preparation of α-olefin drag reducing polymer particles suspension isolation agent. 相似文献
78.
79.
80.
《Physics letters. A》2019,383(17):2082-2089
Nanogrippers have been widely studied for their ability of grasping and manipulating nanoparticles and their capability to be utilized inside SEM, however, due to their very small dimensions, nanogrippers still have widespread complexity in controlling and grasping nanoparticles. In macro grippers, soft materials are used at the surface of end-effectors to reduce the probability of particles damaging, while in nanogrippers, there are limited choices for the nanogrippers and their end-effectors because of manufacturing constraints.In this research, to investigate the behavior of nanoparticles during grasping by end-effectors, this process is simulated and studied numerically. Based on the nature of the problem and the impact of different dimension scales, a 3D multi-scale simulation has been used here. In this way, the effect of materials and hardness of end-effectors surfaces on the stress exerted on nanoparticles, and also the permanent deformation of an open end nanotube as an example of lateral-pressure-sensitive nanoparticles, has been studied. 相似文献