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131.
132.
《Current Applied Physics》2020,20(1):71-77
A confocal Raman microscope (CRM) facilitates visualization of the spatial distribution of molecular bonds or phonon modes at the submicron level and has been extensively used in the characterization of nanomaterials and devices. The lateral and axial resolution is a key specification that defines the performance of CRM, however, the interpretation of spatial resolution in the literature is often ambiguous, making it often difficult to directly compare Raman images obtained under different conditions. In this report, a convenient and reliable measurement protocol using dispersed carbon nanotubes and suspended graphene as test specimens is proposed to facilitate the determination of the lateral and axial resolutions of a CRM. Spatial resolution values comparable to the results based on Rayleigh criterion calculations were obtained using Raman mapping images of test specimens. This was achieved without the need for complex deconvolution processes or the consideration of an asymmetric dielectric environment. 相似文献
133.
提出了一种通过测量微通道板输出电流及增益来计算光电流,从而测量出微通道板量子效率的方法,并用该方法测量了微通道板在近紫外(200~380nm)的量子效率.测量结果表明,微通道板的量子效率很低,并且随波长增加而快速下降,200nm波长处的量子效率为10-4数量级,320nm波长处的量子效率为10-8数量级,大于340nm波长处的量子效率极低且趋近于零.微通道板及荧光屏组成的成像器件可以对酒精灯火焰成像,但图像较稀疏,而传统Cs2Te光电阴极紫外成像器件的图像却较密实,这与微通道板量子效率低,Cs2Te光电阴极量子效率高的情形一致.在该成像器件的前端放置一片350nm波长的高通滤光片后,所成的酒精灯火焰图像消失.对被照射目标成像时,如果照射光源为254nm的汞灯,则可以成像;但如果照射光源为365nm汞灯,则不能成像.说明微通道板的光谱响应主要在350nm波长以下,与其量子效率的测量结果一致.最后测量得到该成像器件的分辨力为32lp/mm,与传统Cs2Te光电阴极紫外成像器件的分辨力相同.微通道板及荧光屏组成的成像器件由于不使用光电阴极,具有价格低、寿命长且可靠性高的优点,因此可在紫外信号较强或成像距离较短的条件下使用. 相似文献
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135.
Dr. Yin-Hui Huang Dr. Yu-Lin Lu Xiao-Dong Zhang Chen-Hui Liu Jia Ruan Yu-Han Qin Zhong-Min Cao Prof. Jijun Jiang Prof. Hai-Sen Xu Prof. Cheng-Yong Su 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(2):e202315053
A series of isostructural supramolecular cages with a rhombic dodecahedron shape have been assembled with distinct metal-coordination lability (M8Pd6-MOC-16, M=Ru2+, Fe2+, Ni2+, Zn2+). The chirality transfer between metal centers generally imposes homochirality on individual cages to enable solvent-dependent spontaneous resolution of Δ8/Λ8−M8Pd6 enantiomers; however, their distinguishable stereochemical dynamics manifests differential chiral phenomena governed by the cage stability following the order Ru8Pd6 > Ni8Pd6 > Fe8Pd6 > Zn8Pd6. The highly labile Zn centers endow the Zn8Pd6 cage with conformational flexibility and deformation, enabling intrigue chiral-Δ8/Λ8−Zn8Pd6 to meso-Δ4Λ4−Zn8Pd6 transition induced by anions. The cage stabilization effect differs from inert Ru2+, metastable Fe2+/Ni2+, and labile Zn2+, resulting in different chiral-guest induction. Strikingly, solvent-mediated host–guest interactions have been revealed for Δ8/Λ8−(Ru/Ni/Fe)8Pd6 cages to discriminate the chiral recognition of the guests with opposite chirality. These results demonstrate a versatile procedure to control the stereochemistry of metal-organic cages based on the dynamic metal centers, thus providing guidance to maneuver cage chirality at a supramolecular level by virtue of the solvent, anion, and guest to benefit practical applications. 相似文献
136.
In this article, the authors obtain some theoretical results for 2_(IV)~(m-p) designs to have the maximum number of clear two-factor interactions by considering the number of two-factor interactions that are not clear. Several 2_(IV)~(m-p) designs with the maximum number of clear two-factor interactions, judged using these results, are provided for illustration. 相似文献
137.
138.
We prove that every place P of an algebraic function field F|K of arbitrary characteristic admits local uniformization in a finite extension F of F. We show that F|F can be chosen to be Galois, after a finite purely inseparable extension of the ground field K. Instead of being Galois, the extension can also be chosen such that the induced extension FP|FP of the residue fields is purely inseparable and the value group of F only gets divided by the residue characteristic. If F lies in the completion of an Abhyankar place, then no extension of F is needed. Our proofs are based solely on valuation theoretical theorems, which are of particular importance in positive characteristic. They are also applicable when working over a subring R⊂K and yield similar results if R is regular and of dimension smaller than 3. 相似文献
139.
140.