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111.
The effect of the diminution of the sensitizing intensity from initially high value on two-center recording is experimentally and theoretically investigated. A linear diminution of the sensitizing intensity is designed,and three different diminution rates are employed for the experimental investigation. The results show that the dynamic range can be improved by reducing the diminution rate of the sensitizing intensity. Compared with that of traditional two-center recording, the recording sensitivity obtained in the experiment is more improved when the maximum dynamic range is achieved. The effect of the diminution of the sensitizing intensity on grating uniformity and the effect of the initial sensitizing intensity on the recording sensitivity are theoretically investigated. 相似文献
112.
The restoration of pseudo-spin symmetry(PSS) along the N = 32 and N = 34 isotonic chains and the physics behind are studied by applying the relativistic Hartree-Fock theory with the effective Lagrangian PKA1. Taking the proton pseudo-spin partners(π2s_(1/2), π1d_(3/2)) as candidates, the systematic restoration of PSS along both isotonic chains is found from sulphur(S) to nickel(Ni), while an obvious PSS violation from silicon(Si) to sulphur is discovered near the drip lines. The effects of the tensor force components are investigated, introduced naturally by the Fock terms, which can only partially interpret the systematics from calcium to nickel, whereas they fail for the overall trends. Further analysis following the Schr?dinger-like equation of the lower component of Dirac spinor shows that contributions from the Hartree terms dominate the overall systematics of the PSS restoration. Such effects can be self-consistently interpreted by the evolution of the proton central density profiles along both isotonic chains. In particular, the PSS violation is found to tightly relate to the dramatic changes from the bubble-like density profiles in silicon to the central-bumped ones in sulphur. 相似文献
113.
梯形化合物具有大的平面π共轭结构, 不会产生构象扭曲, 可以有效增加π共轭长度, 因而表现出非常好的光电性质. 将主族元素引入到梯形化合物骨架中作为桥接单元不仅可以固定其结构而且由于主族元素和π共轭骨架之间的轨道相互作用, 可以实现对这类化合物光电性质的调节. 采用密度泛函理论对一系列主族元素桥的梯形化合物的结构和光电性质进行了理论研究, 从而可更好地理解和预测这类化合物的性质. 研究发现, 这类化合物的电子结构可以通过引入主族元素进行调节. 由于具有更大的π共轭程度, 四主族元素桥化合物的吸收与双主族元素桥化合物相比有明显的红移, 而且荧光寿命较短. 另外, 通过计算离子化势(IPs)、电子亲和能(EAs)和重组能(λ)考察了这类化合物的电子和空穴注入及传输性质. 研究发现, 四主族元素桥化合物表现出更强的电子和空穴注入能力. 相似文献
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Based on a systematic investigation of J/ψ(ψ')→VP, where V and P stand for light vector and pseudoscalar mesons, we identify the role played by the electromagnetic (EM) transitions and intermediate meson loop transitions, which are essential ingredients for understanding the J/ψ and ψ' couplings to VP. We show that on the one hand, the EM transitions have relatively larger interferences in ψ'→ρπ and K^*^-K +c.c. as explicitly shown by vector meson dominance (VMD). On the other hand, the strong decay of ψ' receives relatively larger destructive interferences from the intermediate meson loop transitions. By identifying these mechanisms in an overall study of J/ψ(ψ') → VP, we provide a coherent understanding of the so-called "ρπ puzzle". 相似文献
116.
We propose one possible mechanism,i.e.,the vector meson (VV) rescattering effects,to interpret the near threshold narrow enhancement observed in J/ψ → γpp.The estimate indicates that these effects can give sizeable contributions to this channel,and a destructive interference between different rescattering amplitudes is required to reproduce the line shape of the data. 相似文献
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纳米生物技术及其应用 总被引:3,自引:0,他引:3
纳米技术的发展使人们可以观测到纳米量级的介观世界,可以直观地了解生物分子的形态和分子间的相互作用,甚至可以操纵生物大分子,得到不同结构的新的生物分子.运用纳米技术制作的纳米器件可以用作疾病诊断与治疗.由纳米量级的超微粒构成的纳米生物材料具有良好生物相容性和一些独特的纳米效应,主要表现为小尺寸效应和表面或界面效应.纳米生物材料与相同组成的微米材料存在非常显著的差异,体现出许多优异的性能和全新的功能.纳米微粒在癌症的监测、治疗,细胞和蛋白质的分离,基因治疗,靶向和缓释控药物等中都有着广泛的应用. 相似文献
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