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981.
982.
采用基于密度泛函理论的第一性原理方法计算了存在Ga空位缺陷和掺杂B原子的二维GaAs的能带结构、态密度和光学性质.计算结果表明空位缺陷二维GaAs显示出金属特性,B原子的引入使体系变为间接带隙半导体,禁带宽度为0.35 eV.态密度计算发现体系低能带主要由Ga的s态、p态、d态和As的s态、p态构成;高能带主要由Ga和As的s态、p态构成.掺杂B原子与存在空位缺陷的二维GaAs相比,静态介电常数相对较低,变为8.42,且易于吸收紫外光,在3.90~8.63 eV能量范围具有金属反射特性,反射率达到52%. 相似文献
983.
984.
985.
本阐明了JP3—1型示波极谱仪电源及显示系统的工作原理,并举例说明这两部分的故障维修。 相似文献
986.
Xiao-Rong Wu Chen-Wei Wu Fei Ding Cheng Tian Wen Jiang Cheng-De Mao Chuan Zhang 《中国化学快报》2017,28(4):851-856
Discrete and symmetric three-dimensional(3D)DNA nanocages have been revoked as excellent candidates for various applications,such as guest component encapsulation and organization(e.g.dye molecules,proteins,inorganic nanoparticles,etc.)to construct new materials and devices.To date,a large variety of DNA nanocages has been synthesized through assembling small individual DNA motifs into predesigned structures in a bottom-up fashion.Most of them rely on the assembly using multiple copies of single type of motifs and a few sophisticated nanostructures have been engineered by co-assembling multi-types of DNA tiles simultaneously.However,the availability of complex DNA nanocages is still limited.Herein,we demonstrate that highly symmetric DNA nanocages consisted of binary DNA point-star motifs can be easily assembled by deliberately engineering the sticky-end interaction between the component building blocks.As such,DNA nanocages with new geometries,including elongated tetrahedron(E-TET),rhombic dodecahedron(R-DOD),and rhombic triacontahedron(R-TRI)are successfully synthesized.Moreover,their design principle,assembly process,and structural features are revealed by polyacryalmide gel electrophoresis(PAGE),atomic force microscope(AFM)imaging,and cryogenic transmission electron microscope imaging(cryo-TEM)associated with single particle reconstruction. 相似文献
987.
Ying‐Hui Wang Li‐Jing Gong Wen‐Yue Dong Ping Lu Zhi‐Hui Kang Tian‐Hao Huang Yu‐Guang Ma Han‐Zhuang Zhang 《Journal of Polymer Science.Polymer Physics》2013,51(12):992-997
The photoexcitation processes of two donor–acceptor‐type copolymers PCFBT with different ratios between the donor and the acceptor ( PCFBT0.5 and PCFBT0.1 ) in the solution system are systematically studied. If the number of the donor is equal to that of the acceptor in one repeat unit (such as PCFBT0.5 ), intrachain charge transfer (ICT) can occur and participate in the relaxation of the excited state after photoexcitation. When the number of donors is much larger than that of acceptors (such as PCFBT0.1 ) in one repeat unit, the ICT character can disappear, and the localized exciton decay process is dominant in the relaxation of the copolymer, which also involves an excitation intensity‐independent vibrational thermal relaxation process at the initial time. The results further the understanding of the basic structure‐property relationship. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 992–996 相似文献
988.
Li Gaoliang He Hui Zheng Weifang Tang Hongbin Li Huirong Lan Tian Liu Xiechun Zhang Hu Yang He Luo Fangxiang Xiao Songtao Ye Guoan 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):279-284
Oxidation of Pu(III) in 1 bp solution to Pu(IV) was studied using the salt-free oxidant N2O4. It was proved that the reductants N,N-dimethylhydroxylamine (DMHAN) and monomethyl-hydrazine (MMH) present in 1 bp solution of CIAE-APOR process can be oxidized and removed from the solutions also by N2O4 before the oxidation of Pu(III). The effects of the acidity, the temperature and the amount of N2O4 added on the oxidation of DMHAN and MMH were studied. 相似文献
989.
Diversified 1,4,5-substituted-2-aminoimidazoles were rapidly assembled via sequential N–H insertion and Grignard addition to α-diazoesters. Lead compounds were identified as antibiotics against Gram-positive bacteria with an MIC value as low as 2 μg/mL. 相似文献
990.
Guang-hui Tian Cun-fang Liu Pu-hui Lai Hua Zhao Feng Nie 《Chemistry of Natural Compounds》2010,46(2):219-221
Taibaihenryiin T was isolated for the first time from Phlomis umbrosa Turcz, and its structure was elucidated on the basis of IR and NMR spectra analysis. Its molecular configuration, conformation,
and crystal structure were also characterized by X-ray structure analysis. The infrequency of the C–O–O–C group is manifested
in this molecular configuration, and hydrogen bonding assembles the molecules into a three-dimensional networking structure
in the crystal. 相似文献