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71.
Crystal Structures of the Fluorochloroplatinates(IV) cis-[(C5H5N)2CH2][PtF4Cl2], trans-[(C5H5N)2CH2][PtF4Cl2] · H2O, and [(C5H5N)2CH2][PtF5Cl] The complex ions cis-[PtF4Cl2]2?, trans-[PtF4Cl2]2? and [PtF5Cl]2? have been synthesized by stereoselective ligand exchange reactions utilizing the trans effect and are separated by ion exchange chromatography on diethylaminoethyl cellulose. These anions form stable AB-type salts with the doubly charged cation dipyridiniomethane, [(C5H5N)2CH2]2+. X-ray structure determinations on single crystals of cis-[(C5H5N)2CH2][PtF4Cl2] ( 1 ) (monoclinic, space group P21/n with a = 10.379(10), b = 9.635(2), c = 13.738(2) Å, β = 99.142(10)°, Z = 4), trans-[(C5H5N)2CH2][PtF4Cl2] · H2O ( 2 ) (triclinic, space group P1 with a = 7.757(4), b = 10.059(7), c = 10.408(6) Å, α = 82.49(5), β = 68.92(4), γ = 75.46(4)°, Z = 2) and [(C5H5N)2CH2][PtF5Cl] ( 3 ) (orthorhombic, space group Pnma with a = 10.394(3), b = 13.320(2), c = 9.2694(10) Å, Z = 4), reveal the perfect ordering of the anion sublattice. The stronger trans influence of Cl compared with F is observed in asymmetric axes $ {\rm F}^ \bullet $? Pt? Cl′. The bond lengths Pt? $ {\rm F}^ \bullet $ are 0.026 Å (1.4%) longer and the Pt? Cl′ distances are 0.078 Å (3,3%) shorter in comparison with those of symmetrically coordinated axes. The weakening of the Pt? $ {\rm F}^ \bullet $ bond and the strengthening of the Pt? Cl′ bond is better recognizable from shifts of the stretching vibrations by 8% to lower and by 13% to higher frequencies, respectively. Correspondingly, the valence force constants are found to be 15% lower and 22% higher. The trans influence is observed most distinctly in the 19F-nmr spectra exhibiting the coupling constant 1J($ {\rm F}^ \bullet $Pt) to be 29% smaller than 1J(FPt). 相似文献
72.
Caroline Rhr 《无机化学与普通化学杂志》1995,621(9):1496-1500
Novel Suboxide Clusters [O5Ba18] in the Crystal Structures of Ba21M2O5 (M = Si, Ge) The compounds Ba21M2O5 (M = Si, Ge) crystallize in the cubic system with space group Fd3m, lattice constants 2 038.3(10) pm (Si), 2 039.8(9) pm (Ge) resp. and Z = 8. The crystal structure contains isolated Si/Ge atoms coordinated by barium atoms in an icosahedral arrangement. The oxygen atoms are situated in the centers of barium octahedra, four of which share common faces with an additional central octahedron. The novel clusters [O5Ba18] in principal are related to those in the crystal structures of the binary Cs/Rb suboxides. 相似文献
73.
Eric J.L. McInnes Grigore A. Timco Richard E.P. Winpenny 《Coordination chemistry reviews》2005,249(23):2577-2590
Studies of two distinct classes of chromium(III) cage complexes are discussed. The first are compact oxo- and carboxylate cages, made by heating precursors to high temperature under a flow of nitrogen. One of these cages, [Cr12O9(OH)3(O2CCMe3)15], has an S = 6 spin ground state which proves a very interesting subject for study by EPR and MCD spectroscopy. Use of other carboxylates leads to other octa- and dodeca-nuclear complexes. The second class of compounds are homo- and hetero-metallic wheels and chains bridged by fluoride and carboxylates. These include the first heterometallic anti-ferromagnetically coupled ring systems and are being widely studied in areas as diverse as magnetic cooling and quantum information processing. The mechanism by which these unusual cyclic and acyclic structures form is discussed. 相似文献
74.
The merocyanine dye 3-ethyl-5-(2-(3-ethyl-2-benzothiazolinylidene)-ethylidene)-rhodanine (BTER) known as Agfa-10 has been found to have a good photoconductivity as solution cast film. In this paper iodine-doped BTER was obtained by doping with iodine vapor. Its structure was investigated with the following characteristies. 1 The doped iodine had been excited as I_3~- anion. 2 Because the electron located on the sulphur atom was transferred to iodine, the charge transfer complex of (BTER-I_3) formed. 3 During the iodine doping process, BTER changed from α-form to β-modification. These had been identified by X-ray diffraction, VIS-absorption spectra and SEM picture.4 From the volt-Ampere curve obtained from sandwich cell, when E≤2.2×10~(-1) V·cm~(-1), the room temperature electrical conductivity of BTER and BTER-I_3 were found to be 2.22×10~(-10) s·cm~(-1) and 2.6×10~(-7) S·cm~(-1), respectively. 相似文献
75.
O. Seidelmann L. Beyer Grit Zdobinsky R. Kirmse F. Dietze R. Richter 《无机化学与普通化学杂志》1996,622(4):692-700
N,N-Dialkyl-N′-ferrocenoylthioureas and Ferrocene-1,1′ -dicarbonic-acid-di-N,N-dialkylthioureides as Ligands for Transition Metals: Synthesis, Acid-Dissociation Constants, X-Ray Structure Determination, and EPR-Single Crystal Investigation Reaction of ferrocenoylisothiocyanate or ferrocene-1,1′ -dicarbonic acid -diisothiocyanate with secondary amines gives N,N-dialkyl-N′ -ferrocenoylthioureas or the respective ferrocene-1,1′-dicarbonic acid-di-N,N-dialkyl-thioureides. The former yield neutral complexes with transition metal ions (Ni2+, Cu2+, Co3+, Pt2+, Fe3+). The acid dissociation constants of the ligands were determined. The EPR spectra of a bis-(N,N-dinbutyl-N′-ferrocenoylthioureato)copper(II) single crystal are discussed. The X-ray structure determination of ferrocene-1,1′-dicarbonic acid-di-N,N-diethyl-thioureide and its different behaviour against Ni2+ and Cu2+ is presented. 相似文献
76.
The analytical methods mass spectrometry, UV/Vis, IR, Raman, Fluorometry, XRD, Mössbauer, and NMR used to elucidate chemical structure are evaluated regarding their capabilities to be used as primary analytical techniques in quantitative measurements, considering the criteria in the CCQM definition of primary methods. This includes a review of the respective measurement equations, the evaluation of the measurement uncertainty, and a discussion of evidence for the “highest metrological level”, as obtained from intercomparisons in contest with other methods. It is shown that only few methods fulfill the CCQM criteria. Quantitative NMR spectroscopy is one of them and may be considered as a potential primary method as recommended by CCQM because of being free of empirical factors in the uncertainty budget. 相似文献
77.
78.
洋葱状富勒烯的提纯研究 总被引:1,自引:0,他引:1
以石墨粉为碳源, Al为催化剂, 采用真空热处理法制备了平均粒径为15~35 nm的洋葱状富勒烯(OLFs).并用CS2分离和空气氧化法对得到的OLFs初产品进行了提纯处理.高分辨透射电镜(HRTEM)、X射线衍射(XRD)、热重分析(TGA)对提纯前后样品的分析表明, CS2分离处理可有效去除初产品中裸露的金属催化剂微粒,然后在空气中610 ℃焙烧200 min,可基本去除无定型碳,并大量去除了石墨状碎片等碳杂质, OLFs的纯度在50%(体积分数)以上. 相似文献
79.
脱铝丝光沸石的制备和结构特征 总被引:1,自引:0,他引:1
用高温水蒸气结合酸洗的方法制备了SiO_2/Al_2O_3为16~186的脱铝丝光沸石。用X光衍射和红外光谱法研究了它们的结构持征。随丝光沸石脱铝,晶格参数呈非线性和各向不同步收缩。由于α方向发生明显收缩,使椭园形主孔道的长轴方向缩小。其骨架振动频率自600~1300cm~(-1)随着脱铝明显向高频方向漂移。当Al/u.c.自4脱至3时,丝光沸石的结构特征发生了明显的变化,可能与骨架上2位铝的脱除有关。当Al/u.c.≤3时,有新的Si—O—Si骨架生成,同时晶体重排为均匀有序的结构。 相似文献
80.
以4种甲基取代戊二烯基为配体合成了4个过渡金属钒开环夹心羰基配合物[2,4-(CH3)2C5H5]2VCO(I),[2,3-(CH3)2C5H5]VCO(Ⅱ),[2-CH3C5H6]2VCO(Ⅲ)和[3-CH3C5H6]2VCO(Ⅳ),其中Ⅱ,Ⅲ,Ⅳ为新配合物,用X射线单晶衍射,IR,EPR法对所合成配合物进行了结构表征,发现I具有两种晶相。 相似文献