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排序方式: 共有207条查询结果,搜索用时 46 毫秒
1.
N. Nishi J. Nishijo K. Judai C. Okabe O. Oishi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,43(1-3):287-290
UV photoexcitation of (t-butylethynyl copper)24
cluster films induces segregation of the crystals into metallic and organic
phases and leads to evolve the metallic sheets sandwiched by organic
polymers. The growth of the metallic crystals in the plane of the
photo-electromagnetic field is attributed due to plasmon-plasmon interaction
among nanoparticles embedded in dielectric polymer matrices. The surface
enhanced photochemical reaction of residual cluster molecules on the photon
incident direction is expected to take an important role for joining the
metal particles to produce a metallic sheet. We can apply this phenomenon
for photolithographic copper pattern generation on a flexible base plate. 相似文献
2.
Cluster ions have been recognized as a superb primary species in time of flight secondary ion mass spectroscopy (ToF-SIMS) compared with monatomic primary ions, as they significantly enhance the secondary ion yields from bulk samples. Self-assembled monolayers provide an important system for studying the fundamental mechanism involved in the yield enhancement.We used a gold cluster ion source to analyze a new type of self-assembled monolayer: a fluorocarbon-grafted polyethylene terephthalate. In addition to the structure details, which helped to understand the grafting mechanism, ToF-SIMS analysis revealed that fluorocarbon secondary ion yield enhancements by cluster ions were due to the enhanced sputter efficiency. A larger information depth may also be expected from the enhancement. Both mathematical definitions of damage cross-section and disappearance cross-section were revisited under a new context. Another cross-section parameter, sputter cross-section, was introduced to differentiate the beam induced sputter process from damage process. 相似文献
3.
研究了利用源内碰撞诱导解离(in-source collision—induced dissociation)的高效液相色谱-大气压化学电离质谱(HPLC—APCI/MS)获取人参和西洋参的化学标志物——人参皂甙Rf和拟人参皂甙F11的特征结构信息及鉴别人参和西洋参的方法。在乙腈-水梯度洗脱反相液相色谱及源内碰撞诱导解离条件下,能获得人参皂甙Rf和拟人参皂甙F11的母核离子及去糖基离子的源内碰撞诱导解离谱,从其差别能清楚区分这对同分异构体。本方法对人参皂甙Rf和拟人参皂甙F11的检出限能达到10^-7g柱上样量,简单、快速,单次质谱实验就能鉴别人参和西洋参。 相似文献
4.
Ar+ sputtering of an Cu(111) surface while simultaneously supplying Mo atoms is known to induce an oriented growth of Mo thin crystals, or seed-layers, on evolving conical Cu protrusions. The seed-layers thus formed are shown to be dual-oriented, or bicrystalline, consisting of columnar crystallites grown homo-epitaxially. The orientation relationship between the two types of crystallites was (100)I (111)II with [001]I [110]II, and this bicrystallinity probably resulted from a non-uniform charge-up of the layers' growth front. As concluded from high-resolution electron microscopy, the Mo(100) stacking is elastically converted into the Mo(111) stacking and vice versa, under the influence of tensile stress. The homo-epitaxy that the seed-layers exhibited is believed to reflect the mutual convertibility of the Mo(100) and (111) stackings. 相似文献
5.
Circular high-performance thin-layer chromatography (HPTLC) has been used to differentiate a series of twelve tricyclic neuroleptics, using both normal phase and reverse phase procedures. The use of normal phase systems also allows the resolution of geometric isomers of chlorprothixene, clopenthixol and flupenthixol. Thirteen sulphonamides and Trirnethoprim may also be distinguished using HPTLC. 相似文献
6.
Ke-Ming Wang Bo-Rong Shi Xiang-Dong Liu Tian-Bing Xu Pei-Ran Zhu Jun-Si Zhu Qing-Tai Zhao 《Applied Physics A: Materials Science & Processing》1992,55(4):332-334
The effect of 2.0 MeV Cu+ irradiation on Si(100) crystal has been studied by the Rutherford backscattering/channeling technique. Analysis of the lattice disorder distribution has been performed under 100 direction of tilting off from the target normal: 7°, 30°, and 45° as well as different doses. The lattice disorder distributions in Si(100) have been compared with TRIM'89 simulation. The results show that the lattice disorder distributions in Si(100) under different irradiation angles seem to be in good agreement with TRIM'89 simulation. When the dose increases up to 8.7×1014 ions/cm2, the defect concentration increases leading to the formation of an amorphous layer. 相似文献
7.
研究了利用源内碰撞诱导解离(in-source collision-induced d issoc iation)的高效液相色谱-大气压化学电离质谱(HPLC-APC I/MS)获取人参和西洋参的化学标志物———人参皂甙R f和拟人参皂甙F11的特征结构信息及鉴别人参和西洋参的方法。在乙腈-水梯度洗脱反相液相色谱及源内碰撞诱导解离条件下,能获得人参皂甙R f和拟人参皂甙F11的母核离子及去糖基离子的源内碰撞诱导解离谱,从其差别能清楚区分这对同分异构体。本方法对人参皂甙R f和拟人参皂甙F11的检出限能达到10-7g柱上样量,简单、快速,单次质谱实验就能鉴别人参和西洋参。 相似文献
8.
The use of thermal energy atom scattering (TEAS) as a surface investigation tool is reviewed. Specific properties of thermal He scattering, which are particularly advantageous in surface analysis, are discussed; the main causes which hampered so far the broad application of this technique to the investigation of ordered surfaces are analysed. The recent development of TEAS based on the exploitation of the large cross section for He diffuse scattering of adsorbates and vacancies is reviewed. This development extends the capabilities of TEAS to a straightforward investigation of various aspects of disordered surfaces so far hardly accessible to other methods. Examples concerning the lateral distribution of adsorbates and defects, the mutual attraction and repulsion, 2D-phase transitions, mobility and surface diffusion are given. 相似文献
9.
Morphologies and optical properties of poly(2,5-diethoxyphenylene) nanofibril arrays 总被引:1,自引:0,他引:1
An anodic aluminum oxide (AAO) membrane can be used as a template for the synthesis of nanostructures. In this paper, we have
fabricated poly(2,5-diethoxyphenylene) (EtO-PPP) nanofibril arrays by oxidative coupling polymerization of 1,4-diethoxybenzene
(DEB) within the pores of an AAO template. The detailed molecular structure of the polymer nanofibrils was characterized by
using the infrared spectrum and the 1H-NMR spectrum. We have used transmission electron microscopy, scanning electron microscopy, and atomic force microscopy to
confirm the morphologies and images of the template and the fabricated nanometer scale of poly(2,5-diethoxyphenylene)nanofibril
arrays. The experimental results demonstrate that the pores of the AAO membrane are regular and uniform, and parallel to each
other. Furthermore, the EtO-PPP chains in the narrowest template-synthesized fibrils were oriented parallel to the pore axes
of the AAO membrane, and perpendicular to the surface of the aluminum substrate. The polymer chain orientation is partially
responsible for the enhanced conductivity. The ultraviolet absorption maximum shows that the polymer contains a better extended
π-conjugation system along the poly(p-phenylene) backbone, which results in a longer-wavelength shift of the absorption band.
The photoluminescence (PL) spectrum of nanofibril arrays exhibits a 5-nm blue shift of the emission in comparison with the
unordered molecules.
Received: 3 January 2002 / Accepted: 7 January 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86-931/891-1100, E-mail: lihl@lzu.edu.cn 相似文献
10.
The rf pulse response of I=3/2 spin system experiencing first order quadrupolar splitting is studied using density matrix approach. A general expression is derived in terms of spin populations, quadrupole splitting and duration and amplitude of the rf pulse for calculating the NMR signal arising due to the centre line and satellite resonances for the situation where the impressed rf pulse excites the resonances selectively as well as non-selectively. The necessary 4×4 transformation matrix obtained analytically by diagonalyzing the Hamiltonian are used to get the expression for the centre line response. The satellite signals are obtained in the same way but by using the numerical values of the roots of the related quartics. The widths of the corresponding π/2-pulses are calculated for different initial spin populations. The variations of this pulse-width and the corresponding signal amplitude as a function of satellite splitting are studied. 相似文献