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991.
Yan-Chun Bai 《Journal of solid state chemistry》2009,182(1):89-4034
Three new polyoxometalates X7[PMo8O30] (X=Na+, 1; K+, 2; NH4+, 3) have been synthesized with the classical Keggin and/or Dawson heteropolymolybdophosphates and PCl5 in acetonitrile-water solutions via hydrothermal treatment. The three compounds were characterized by different analyses including IR, 31P NMR spectroscopy, elemental analysis, electrochemistry, thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD). Single crystal X-ray analyses were carried out on Na7[PMo8O30] (1) and (NH4)7[PMo8O30] (3). Compound 1 and 3 crystallize in the orthorhombic system. The structure of compound 2 was confirmed by the IR spectra and powder XRD. All the three compounds contain the same octamolybdophosphate polyoxoanion [PMo8O30]7−, which consists of two Mo4O15 moieties linked by one central PO4 tetrahedron, leading to a remarkable sandglass-like structure. 相似文献
992.
David M. Good Craig D. Wenger Graeme C. McAlister Dina L. Bai Donald F. Hunt Joshua J. Coon 《Journal of the American Society for Mass Spectrometry》2009,20(8):1435-1440
Tandem mass spectra (MS/MS) produced using electron transfer dissociation (ETD) differ from those derived from collision-activated
dissociation (CAD) in several important ways. Foremost, the predominant fragment ion series are different: c- and z
·-type ions are favored in ETD spectra while b- and y-type ions comprise the bulk of the fragments in CAD spectra. Additionally, ETD spectra possess charge-reduced precursors
and unique neutral losses. Most database search algorithms were designed to analyze CAD spectra, and have only recently been
adapted to accommodate c- and z
·-type ions; therefore, inclusion of these additional spectral features can hinder identification, leading to lower confidence
scores and decreased sensitivity. Because of this, it is important to pre-process spectral data before submission to a database
search to remove those features that cause complications. Here, we demonstrate the effects of removing these features on the
number of unique peptide identifications at a 1% false discovery rate (FDR) using the open mass spectrometry search algorithm
(OMSSA). When analyzing two biologic replicates of a yeast protein extract in three total analyses, the number of unique identifications
with a ∼1% FDR increased from 4611 to 5931 upon spectral pre-processing—an increase of ∼28. 6%. We outline the most effective
pre-processing methods, and provide free software containing these algorithms. 相似文献
993.
Junhu Zhang Zhiqiang Sun Bai Yang 《Current Opinion in Colloid & Interface Science》2009,14(2):103-114
This article reviews recent developments in self-assembly of polymer colloids into colloidal crystals, a good candidate material for photonic crystals. Self-assembly strategy has developed as a facile and efficient method to fabricate colloidal crystals. Much research work has been focused on controlling the morphology and improving the quality, as well as finding applications of the colloidal crystals. 相似文献
994.
Ying Bai Chuan Wu Feng Wu Li-xin Yang Bo-rong Wu 《Electrochemistry communications》2009,11(1):145-148
High active FeB alloy was prepared by an electric arc method, and used as the anode material for alkaline secondary batteries. The structural characteristics of the as-prepared FeB alloy were studied using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances were investigated using cyclic voltammetry (CV) and charge–discharge test. The FeB alloy achieves an excellent reversible capacity of 312 mA h/g as well as a good cycleability, and is proved to be a promising low-cost and high performance anode material for alkaline secondary batteries. 相似文献
995.
Jian-Po Zhang Xin Zhou Fu-Quan Bai Hong-Xing Zhang Au-Chin Tang 《Theoretical chemistry accounts》2009,122(1-2):31-42
The geometries, electronic structures, and spectroscopic properties of a series of [Os(II)(CO)3(tfa)(acac(X)2)] (tfa = trifluoroacetate; acac = acetoylacetonate; X = H (1), CF3 (2), C6H5 (3), and C10H7 (4)) complexes have been investigated theoretically. The ground and excited state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. The optimized geometry structural parameters agreed well with the corresponding experimental results. As indicated in this paper, the highest occupied molecular orbitals were dominantly localized on the Os atom, ctfa (abbv. of CO and tfa), and acac ligand for 1 and 2, acac ligand and X substituent for 3 and 4, while the lowest unoccupied molecular orbitals were mainly composed of acac ligand and X substituent. Under the time-dependent density functional theory (TDDFT) level with the polarized continuum model (PCM), the absorption and phosphorescence in CH2Cl2 media were calculated based on the optimized ground- and excited-state geometries, respectively. The calculated results show that the lowest energy absorptions at 317 (1), 342 (2), 377 (3), and 420 nm (4) are attributed to a change of ππ*/MLCT mixing transition to pure ππ* transition for 1–4, while their phosphorescence emission have similar transition properties. This indicates that the absorption and emission transition characters could be altered by adjusting the π electron-donating ability. 相似文献
996.
Zhengwei Mao Dr. Jinshan Guo Shuo Bai Tich‐Lam Nguyen Dr. Haibing Xia Dr. Yubin Huang Prof. Paul Mulvaney Prof. Dayang Wang Dr. 《Angewandte Chemie (International ed. in English)》2009,48(27):4953-4956
In the swim : Colloidal nanoparticles coated with polylactide (PLA, red) and poly(ethylene glycol) brushes (PEG, black) can transfer from organic to aqueous phases across liquid/liquid or liquid/gel interfaces during degradation of the PLA coating (see picture: first step), which is driven selectively by the hydrogen bonding of the PEG coating with the aqueous phase (second step).
997.
Jianhua Xie Weiling Kong Xiaocheng Wang Wenju Bai Lixin Wang Qilin Zhou 《Frontiers of Chemistry in China》2009,4(3):299-306
The asymmetric hydrogenation of the conformationally flexible racemic α-substituted acyclic dialkyl ketones via dynamic kinetic
resolution (DKR) has been developed by using Ru-SDPs/diamine catalysts. Chiral alcohols were produced in high yields with
good to excellent enantioselectivities (85%–97% ee) and diastereoselectivities (up to 97:3). This hydrogenation reaction provided
a new approach to the synthesis of the key intermediate of J-104118. 相似文献
998.
999.
He-Xiang Bai Jing-Mei Wang Shi-Jing Xia Quan-Rui Wang 《Journal of chemical crystallography》2011,41(3):316-321
Abstract
A novel pentaheterocyclic ring system derived from (5α)-cholestan-3-one, i.e. [1R-[1α(R*),3aβ,3bα,5aβ,12aα,12bβ,14aα]]-1-(1,5-dimethylhexyl)-1,2,3,3a,3b,4,5,11,12,12a,12b,13,14,14a-tetradecahydro-8,12a,14a-trimethyl-9-(2,4,6-trichlorophenyl)-cyclopenta[5,6]naphtho[2,1-d][1,2,4]triazolo[1,5-a]azepinium hexachloroantimonate (6) has been synthesized via the reverse-electron-demand 1,3-dipolar cycloaddition of the 1-aza-2-azoniaallene cation 4 to the triple bond of acetonitrile followed by ring enlargement. The structure of 6 was determined by NMR, IR and high-resolution mass spectra, and unequivocally confirmed by X-ray crystallographic analysis. The title compound crystallizes in monoclinic class under the space group P2-1 with a = 8.163(3) ?, b = 11.214(4) ?, c = 24.191(9) ?, α = 90°, β = 97.740(5)°, and γ = 90°. The five-membered triazole ring is essentially planar and aromatic, while the seven-membered azepine ring is not planar, but adopts a chair-like conformation. 相似文献1000.
Dongbin Dang Haiyan Li Guangshui Zheng Yan Bai 《Journal of chemical crystallography》2011,41(11):1612-1615