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991.
胆红素络合物的表面增强拉曼光谱研究 总被引:5,自引:0,他引:5
本文通过对近红外激发傅里叶变换拉曼光谱(NIR-FT-Raman)与表面增强拉曼散射(Surface Enhanced Raman Scattering,SERS)技术的联用,测得胆红素及其络合物Na2BR,CaBR与CuBR在银溶胶中的SERS光谱.结果表明,这一类与胆结石密切相关的生物分子络合物具有不同的配位方式,且在银胶表面采取不同的吸附取向,并从配位化学角度初步解释了黑色结石的黑色成因. 相似文献
992.
通过透射光谱、x射线激发发射光谱(XSL)的测试,研究了Bridgman法生长的几种不同+3价离子掺杂钨酸铅晶体的发光性能,并利用正电子湮没寿命谱(PAT)和x光电子能谱(XPS)的实验手段,对不同钨酸铅晶体的微观缺陷进行研究.实验表明,不同的+3价离子掺杂,对钨酸铅晶体发光性能的改善不同,并使得晶体中正电子俘获中心和低价氧的浓度发生不同变化.其中掺镧晶体的正电子俘获中心和低价氧浓度均上升,而掺钇和掺铋晶体的正电子俘获中心和低价氧浓度均下降,掺锑晶体则出现了正电子俘获中心浓度上升、低价氧浓度下降的情况.提
关键词:
钨酸铅晶体
+3价离子掺杂
正电子湮没寿命谱
x光电子能谱 相似文献
993.
994.
Determination of the surface states from the ultrafast electronic states in a thermoelectric material
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We reveal the electronic structure in Yb Cd2Sb2,a thermoelectric material,by angle-resolved photoemission spectroscopy(ARPES)and time-resolved ARPES(tr ARPES).Specifically,three bulk bands at the vicinity of the Fermi level are evidenced near the Brillouin zone center,consistent with the density functional theory(DFT)calculation.It is interesting that the spin-unpolarized bulk bands respond unexpectedly to right-and left-handed circularly polarized probe.In addition,a hole band of surface states,which is not sensitive to the polarization of the probe beam and is not expected from the DFT calculation,is identified.We find that the non-equilibrium quasiparticle recovery rate is much smaller in the surface states than that of the bulk states.Our results demonstrate that the surface states can be distinguished from the bulk ones from a view of time scale in the nonequilibrium physics. 相似文献
995.
Dr. Mu Xiao Lei Zhang Dr. Bin Luo Dr. Miaoqiang Lyu Dr. Zhiliang Wang Hengming Huang Dr. Songcan Wang Prof. Aijun Du Prof. Lianzhou Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7297-7301
Atomic co-catalysts offer high potential to improve the photocatalytic performance, of which the preparation with earth-abundant elements is challenging. Here, a new molten salt method (MSM) is designed to prepare atomic Ni co-catalyst on widely studied TiO2 nanoparticles. The liquid environment and space confinement effect of the molten salt leads to atomic dispersion of Ni ions on TiO2, while the strong polarizing force provided by the molten salt promotes formation of strong Ni−O bonds. Interestingly, Ni atoms are found to facilitate the formation of oxygen vacancies (OV) on TiO2 during the MSM process, which benefits the charge transfer and hydrogen evolution reaction. The synergy of atomic Ni co-catalyst and OV results in 4-time increase in H2 evolution rate compared to that of the Ni co-catalyst on TiO2 prepared by an impregnation method. This work provides a new strategy of controlling atomic co-catalyst together with defects for efficient photocatalytic water splitting. 相似文献
996.
Yuanyuan Yang Lifu Zhang Prof. Zhenpeng Hu Dr. Yao Zheng Dr. Cheng Tang Prof. Ping Chen Ruguang Wang Kangwen Qiu Dr. Jing Mao Prof. Tao Ling Prof. Shi-Zhang Qiao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(11):4555-4561
Cost-effective carbon-based catalysts are promising for catalyzing the electrochemical N2 reduction reaction (NRR). However, the activity origin of carbon-based catalysts towards NRR remains unclear, and regularities and rules for the rational design of carbon-based NRR electrocatalysts are still lacking. Based on a combination of theoretical calculations and experimental observations, chalcogen/oxygen group element (O, S, Se, Te) doped carbon materials were systematically evaluated as potential NRR catalysts. Heteroatom-doping-induced charge accumulation facilitates N2 adsorption on carbon atoms and spin polarization boosts the potential-determining step of the first protonation to form *NNH. Te-doped and Se-doped C catalysts exhibited high intrinsic NRR activity that is superior to most metal-based catalysts. Establishing the correlation between the electronic structure and NRR performance for carbon-based materials paves the pathway for their NRR application. 相似文献
997.
溶质带中的众多分子在固定相-流动相环境中的色谱分离过程能够类比成疾病高危人群在多种暴露因素的疾病严重程度排序。色谱过程和机器疾病诊断-医嘱的共性在于对成分或个体疾病状态的分离或分类,二者都表现出随时间演化的不可逆性,但前者属于线性非平衡热力学而后者属于耗散结构的非线性非平衡热力学。当将科学视野从药物检测和制备扩展到循证医学、离散数学(公理集合论、概率测度)、人工智能(AI)-云计算领域时,对流-扩散方程和非平衡热力学中的不可逆性就成了色谱分离和智慧医疗两个交叉领域的共同的、核心的数学物理本质。抓住不可逆性这一学科间的共性特征,构建和发展这两个领域统一的、全覆盖的数学构架,具有深远的科学和现实意义。 相似文献
998.
Wang Guishuo Luo Ran Yang Chengsheng Song Jimin Xiong Chuanye Tian Hao Zhao Zhi-Jian Mu Rentao Gong Jinlong 《中国科学:化学(英文版)》2019,62(12):1710-1719
Science China Chemistry - Metal oxide-promoted Rh-based catalysts have been widely used for CO2 hydrogenation, especially for the ethanol synthesis. However, this reaction usually suffers low CO2... 相似文献
999.
The double-layer penetration electrode structure is proposed to obtain the low-operating voltage blue-phase liquid crystal display (BPLCD) with single electro-optic curve for red-green-blue (RGB) colours in every pixel, which is more suitable for the field-sequential-colour display. The different influences of electrode’s parameters and driving methods on the electro-optical properties of the proposed BPLCD are investigated. The results demonstrate that the operating voltage can be reduced from 53.80 V to 23.00 V for red colour. Besides, the coincident voltage-dependent transmittance curves for RGB colours are obtained by adjusting the applied voltage of sub-electrode. Thus, RGB lights can pass through every pixel with single electro-optic curve, which is good for resolution enhancement and single gamma driving. Besides, the maximum gamma shift of the proposed BPLCD is less than 0.1099 at 60° polar angle for the red colour, and the gamma shift difference between red and blue colours is only 0.0542. If the high dielectric constant material is used as the protrusion, the operating voltage can be further decreased, which is close to that of the BPLCD with wall-shaped electrode structure. 相似文献
1000.
Johanna Camacho Gonzalez Sukanta Mondal Fernanda Ocayo Raul Guajardo-Maturana Alvaro Muñoz-Castro 《International journal of quantum chemistry》2020,120(3):e26080
The search for efficient synthetic hosts able to encapsulate fullerenes has attracted attention with regard to the purification and formation of ordered supramolecular architectures. This study of a porphyrin-based cage as an extension of the well-described ExCage6+ and BlueCage6+, involving viologen as sidearms, provides an interesting scenario where the oblate C70 fullerene is preferred in comparison to the spherical C60. Our results expose the nature of the fullerene-cage interaction involving ∼50% of dispersion-type interactions evidencing the strong π⋯π surface stacking, with a complementary contribution by the electrostatic and orbital polarization character produced by a charge reorganization with a charge accumulation facing the porphyrin macrocycles and a charge depletion along the equator formed by the viologens sidearms. Interestingly, the central N4H2 ring from each porphyrin contributes to the dispersion term via N-H⋯π interactions, which is decreased when the metallate N4Zn is evaluated. Thus, the formation of stable and selective fullerene encapsulation can be achieved by taking into account two main driving forces, namely, (a) the extension of the π⋯π and X-H⋯π stacking surface and (b) charge reorganization over the fullerene surfaces, which can be used to control fine tuning of the encapsulation thanks to the introduction of more electron-deficient and electron-rich groups within the host cage. 相似文献