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941.
Oxovanadium(IV), copper(II) or cobalt(II) acetylacetone complexes immobilized on amino‐functionalized CMK‐3 for the aerobic epoxidation of styrene
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Xiufang Wang Shujie Wu Zhifang Li Xiaoyuan Yang Jing Hu Qisheng Huo Jingqi Guan Qiubin Kan 《应用有机金属化学》2015,29(10):698-706
Oxovanadium(IV), copper(II) and cobalt(II) acetylacetone complexes have been grafted onto amino‐modified CMK‐3‐O (VO‐NH2‐CMK‐3, Cu‐NH2‐CMK‐3 and Co‐NH2‐CMK‐3,respectively) and the materials thus prepared were used as heterogeneous catalysts for the aerobic oxidation of styrene. X‐ray diffraction, nitrogen adsorption–desorption and transmission electron microscopy measurements confirmed the structural integrity of the mesoporous hosts, and spectroscopic characterization techniques (Fourier transform infrared, X‐ray photoelectron, Raman) and thermogravimetry confirmed the ligands and the successful anchoring of the acetylacetone complexes to the modified mesoporous support. VO‐NH2‐CMK‐3 displayed a relatively good catalytic performance with 94.6% of styrene conversion using air as oxidant, while Cu‐NH2‐CMK‐3 gave 99.6% of styrene conversion using tert‐butyl hydroperoxide as oxidant. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
942.
A Highly Selective Two‐Photon Fluorescent Probe for Detection of Cadmium(II) Based on Intramolecular Electron Transfer and its Imaging in Living Cells
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Dr. Zhaohua Shi Qingxin Han Dr. Lizi Yang Huan Yang Dr. Xiaoliang Tang Dr. Wei Dou Zhiqi Li Yange Zhang Yongliang Shao Liping Guan Prof. Dr. Weisheng Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):290-297
A new quinoline‐based probe was designed that shows one‐photon ratiometric and two‐photon off–on changes upon detecting Cd2+. It exhibits fluorescence emission at 407 nm originating from quinoline groups in Tris‐HCl (25 mM , pH 7.40), H2O/EtOH (8:2, v/v). Coordination with Cd2+ causes quenching of the emission at 407 nm and simultaneously yields a remarkable redshift of the emission maximum to 500 nm with an isoemissive point at 439 nm owing to an intramolecular charge‐transfer mechanism. Thus, dual‐emission ratiometric measurement with a large redshift (Δλ=93 nm) and significant changes in the ratio (F500/F439) of the emission intensity (R/R0 up to 27) is established. Moreover, the sensor H2L displays excellent selectivity response, high sensitive fluorescence enhancement, and strong binding ability to Cd2+. Coordination properties of H2L towards Cd2+ were fully investigated by absorption/fluorescence spectroscopy, which indicated the formation of a 2:1 H2L/Cd2+ complex. All complexes were characterized by X‐ray crystallography, and TD‐DFT calculations were performed to understand the origin of optical selectivity shown by H2L. Two‐photon fluorescence microscopy experiments have demonstrated that H2L could be used in live cells for the detection of Cd2+. 相似文献
943.
944.
945.
Thiols play vital and irreplaceable roles in the biological system. Abnormality of thiol levels has been linked with various diseases and biological disorders. Thiols are known to distribute unevenly and change dynamically in the biological system. Methods that can determine thiols’ concentration and distribution in live cells are in high demand. In the last two decades, fluorescent probes have emerged as a powerful tool for achieving that goal for the simplicity, high sensitivity, and capability of visualizing the analytes in live cells in a non-invasive way. They also enable the determination of intracellular distribution and dynamitic movement of thiols in the intact native environments. This review focuses on some of the major strategies/mechanisms being used for detecting GSH, Cys/Hcy, and other thiols in live cells via fluorescent probes, and how they are applied at the cellular and subcellular levels. The sensing mechanisms (for GSH and Cys/Hcy) and bio-applications of the probes are illustrated followed by a summary of probes for selectively detecting cellular and subcellular thiols. 相似文献
946.
Luminescent ruthenium(II) complex covalently bound silica nanoparticles have been prepared and used as a probe for time-gated luminescence bioimaging. The new nanoparticles were prepared by copolymerization of a luminescent Ru(II) complex tris(5-amino-1,10-phenanthroline)ruthenium(II) conjugated with 3-aminopropyl(triethoxy)silane (APS-Ru conjugate), free (3-aminopropyl)triethoxysilane (APS) and tetraethyl orthosilicate (TEOS) in a water-in-oil reverse microemulsion consisting of Triton X-100, n-octanol, cyclohexane and water in the presence of aqueous ammonia. Characterization by transmission electron microscopy indicates that the nanoparticles are monodisperse, spherical and uniform in size, 64 ± 4 nm in diameter. Compared with the dye-doping nanoparticles, dye leakage of the new nanoparticles was remarkably decreased. In addition, it was found that the Ru(II) complex luminescence could be effectively enhanced with a longer luminescence lifetime (∼2.3 μs) after forming the nanoparticles, which enables the nanoparticles to be suitable as a bioprobe for time-gated luminescence bioimaging applications. The nanoparticle-labeled streptavidin was prepared and successfully used for time-gated luminescence imaging detection of an environmental pathogen, Giardia lamblia, with high specificity and sensitivity. 相似文献
947.
948.
Chun Hua Ge Xiang Dong Zhang Yong Chao Ma Lei Guan Chun Yue Shi Xiao Yan Zhang Ya Nan Guo Qi Tao Liu 《中国化学快报》2007,18(11):1389-1391
The preparation and crystal structure of complex Co(Hsae)2·2H2O (1, H2sae = N-salicylidene-2-iminoethanol) are reported. X- ray analysis revealed that every six Co(Hsae)2 forms a cyclic chip and every 12 water forms a novel gear-like cluster. Acting as building blocks, the gear-like water cluster and complex chip are connected in A-B fashion and extend into one-dimensional supramolecular chain. Hydrogen bond is the primary bridging force in the formation of supramolecular framework. 相似文献
949.
A series of transition metal phosphides, including MoP, WP, CoP, Co2P, and Ni2P, were synthesized from their oxidic precursors by means of hydrogen plasma reduction under mild conditions. The effects of reduction conditions, such as metal to phosphorus molar ratio, power input, and reduction time, on the synthesis of metal phosphides were investigated. The products were identified by means of XRD characterization. It is indicated that metal phosphides were readily synthesized stoichiometrically from their oxides in hydrogen plasma under mild conditions. 相似文献
950.
Bond distances, vibrational frequencies, electron affinities, ionization potentials, dissociation energies and dipole moments
of the title molecules in neutral, positively and negatively charged ions were studied by use of density functional method.
Ground electronic state was assigned for each molecule. The bonding patterns were analyzed and compared with both the available
data and across the series. It was found that besides ionic component, covalent bonds are formed between the metal s, d and
f orbitals and oxygen p orbitals. Contrary to the well known lanthanide contraction, the bond distance is not regular from
LaO to LuO for both neutral and charged molecules. An obvious population at 5d orbital was observed through the lanthanide
series. 4f electrons also participate the chemical bonding for CeO to NdO and TbO to TmO. For EuO, GdO, YbO and LuO, 4f electrons
tend to be localized. The spin multiplicity is regular for neutral and charged molecules. The spin multiplicity of the charged
molecules can be obtained by −1 (or +1 for TbO+, DyO+, YbO− and YbO+) compared with the corresponding neutral molecules. 相似文献