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111.
碱熔-氢化物发生原子荧光光谱法连续测定锑精矿中的砷、铋、硒、锡 总被引:6,自引:1,他引:5
建立了氢化物发生原子荧光光谱法测定锑精矿中砷、铋、硒、锡的方法.研究了基体及共存元素的干扰情况,实验表明,在酒石酸、硫脲-抗坏血酸存在下,适当的增加酸度可以有效地消除干扰.采用Na2O2熔解样品,用HCl酸化,无需分离基体,实现了锑精矿中砷、铋、硒、锡的连续测定,其回收率为90.6%~103.8%,检出限分别为0.35、0.20、0.65和0.35 μg/L.应用该方法分析了锑精矿样品,结果令人满意. 相似文献
112.
Slejkovec Z Falnoga I Goessler W van Elteren JT Raml R Podgornik H Cernelc P 《Analytica chimica acta》2008,607(1):83-91
Urine and blood samples of cancer patients, treated with high doses of arsenic trioxide were analysed for arsenic species using HPLC-HGAFS and, in some cases, HPLC-ICPMS. Total arsenic was determined with either flow injection-HGAFS in urine or radiochemical neutron activation analysis in blood fractions (in serum/plasma, blood cells). The total arsenic concentrations (during prolonged, daily/weekly arsenic trioxide therapy) were in the μg mL−1 range for urine and in the ng g−1 range for blood fractions. The main arsenic species found in urine were As(III), MA and DMA and in blood As(V), MA and DMA.With proper sample preparation and storage of urine (no preservation agents/storage in liquid nitrogen) no analytical artefacts were observed and absence of significant amounts of alleged trivalent metabolites was proven. On the contrary, in blood samples a certain amount of arsenic can get lost in the speciation procedure what was especially noticeable for the blood cells although also plasma/serum gave rise to some disappearance of arsenic. The latter losses may be attributed to precipitation of As(III)-containing proteins/peptides during the methanol/water extraction procedure whereas the former losses were due to loss of specific As(III)-complexing proteins/peptides (e.g. cysteine, metallothionein, reduced GSH, ferritin) on the column (Hamilton PRP-X100) during the separation procedure. Contemporary analytical protocols are not able to completely avoid artefacts due to losses from the sampling to the detection stage so that it is recommended to be careful with the explanation of results, particularly regarding metabolic and pharmacokinetic interpretations, and always aim to compare the sum of species with the total arsenic concentration determined independently. 相似文献
113.
Xue Min Ivan A. Popov Fu‐Xing Pan Dr. Lei‐Jiao Li Eduard Matito Prof. Dr. Zhong‐Ming Sun Prof. Dr. Lai‐Sheng Wang Prof. Dr. Alexander I. Boldyrev 《Angewandte Chemie (International ed. in English)》2016,55(18):5531-5535
Antiaromaticity, as introduced in 1965, usually refers to monocyclic systems with 4n π electrons. This concept was extended to all‐metal molecules after the observation of Li3Al4? in the gas phase. However, the solid‐phase counterparts have not been documented to date. Herein, we describe a series of all‐metal antiaromatic anions, [Ln(η4‐Sb4)3]3?(Ln=La, Y, Ho, Er, Lu), which were isolated as the K([2.2.2]crypt) salts and identified by single‐crystal X‐ray diffraction. Based on the results obtained from the chemical bonding analysis, multicenter indices, and the electron‐counting rule, we conclude that the core [Ln(η4‐Sb4)3]3? fragment of the crystal has three locally π‐antiaromatic Sb4 fragments. This complex represents the first locally π‐antiaromatic all‐metal system in the solid state, which is stabilized by interactions of the three π‐antiaromatic units with the central metal atom. 相似文献
114.
Dr. Robert J. Wilson Dr. Lies Broeckaert M. Sc. Fabian Spitzer Priv.‐Doz. Dr. Florian Weigend Prof. Dr. Stefanie Dehnen 《Angewandte Chemie (International ed. in English)》2016,55(39):11775-11780
Reaction of the binary Zintl anion (Sn2Sb2)2? with the β‐diketiminato complex [LCu(NCMe)] (L=nacnac=[(N(C6H3iPr2‐2,6)C(Me))2CH]?) in ethylenediamine or DMF affords the ternary cluster dimer {[CuSn5Sb3]2?}2 ( 1 ) as its [K(crypt‐222)]+ salt. The chemical formulation of 1 is supported by energy‐dispersive X‐ray spectroscopy (EDX) and quantum chemical calculations. Each monomeric part of the dimer represents a trimetallic “[CuSn5Sb3]2?” cluster, with an architecture in between a tricapped trigonal prism and a capped square antiprism. As shown by quantum chemical investigations, the presence of Sb atoms and, in particular, of Cu atoms in the cluster skeleton makes the monomeric unit behave like an inhomogeneous superatom, which clearly prefers to dimerize, thereby producing a relatively short, yet virtually non‐bonding Cu???Cu distance. 相似文献
115.
Trevor T. Chiweshe Marilé Landman Jeanet Conradie 《Journal of Coordination Chemistry》2016,69(5):788-800
In view of the important role of dithizone in trace metal analyses, new structural aspects and approaches used to probe metal complexes of dithizone are of interest. Three X-ray diffraction structures are reported, dichloridobis(dithizonato)tin(IV), dichlorido(dithizonato)antimony(III), and bis(dithizonato)copper(II). During synthesis of the tin complex, auto-oxidation of SnIICl2 to SnIV occurred without chloride liberation. The SbIII complex revealed a unique distorted see-saw geometry which is, as for the other complexes, predicted by DFT molecular orbital calculations. The computed products of the lowest energy reactions are in agreement with experimentally obtained reaction products, which, together with molecular orbital renderings serve as a tool toward prediction of modes of coordination in these complexes. The S–M–N bond angle in the five-membered coordination ring shows a linear relationship with the corresponding metal ionic radii. 相似文献
116.
El-Safty SA Ismail AA Matsunaga H Mizukami F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(33):9245-9255
Appropriate design of nanosensors for optically selective, sensitive sensing systems is needed for naked-eye detection of pollutants for environmental cleanup of toxic heavy-metal ions. Mesostructured materials with two- or three-dimensional (2D or 3D) geometries and large particle morphologies show promise as probe carriers, and can therefore be used to reproducibly fabricate uniformly packed nanosensors. This is the first report on the effects of significant key properties of the mesostructured carriers, such as morphology, geometry, and pore shape, on the functionality of optical nanosensor designs. Such mesostructured sensors with superior physical characteristics can be used as components in sensing systems with excellent stability and sensitivity, and with rapid detection response. The nanosensor design can enhance the selectivity even at low concentrations of the pollutant target ions (nanomolar level). Among the nanosensors developed here, the large pore-surface grains of highly ordered 3D monoliths (HOM) exhibited a high adsorption capability of the Pyrogallol Red probe and high accessibility to analyte ion transport, leading to possible naked-eye detection of Sb(III) ions at concentrations as low as 10(-9) mol dm(-3) and at a wide detection range of 0.5 ppb to 3 ppm. A key finding in our study was that our mesostructured nanosensor designs retained highly efficient sensitivity without a significant increase in kinetic hindrance, despite the slight decrease of the specific activity of the electron acceptor/donor strength of the probe functional group after several regeneration/reuse cycles. The results, in general, indicate that large-scale reversibility of optical nanosensors is feasible in such metal-ion sensing systems. 相似文献
117.
Schröder G Okinaka T Mimura Y Watanabe M Matsuzaki T Hasuoka A Yamamoto Y Matsukawa S Akiba KY 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(9):2517-2529
All possible combinations of mixed pentaarylantimony compounds bearing p-methylphenyl and p-trifluoromethylphenyl groups were synthesized; ArnTol5-nSb (n=0-5: Ar=p-CF3C6H4, Tol=p-CH3C6H4): Tol5Sb (1), ArTol4Sb (2), Ar2Tol3Sb (3), Ar3Tol2Sb (4), Ar4TolSb (5), and Ar5Sb (6). Compounds 2-5 are the first well-characterized examples of mixed acyclic pentaarylantimony species. The structures of 2-6 were determined by X-ray crystallography to feature trigonal-bipyramidal (TBP) geometry with the more electronegative p-trifluoromethylphenyl substituents selectively occupying the apical positions. Consideration of the chemical shifts of the ipso carbons of the aryl and tolyl groups suggested that the solution structures of 1-6 were also TBP, although their pseudorotation could not be frozen even at -80 degrees C. Ligand-exchange reactions (LERs) took place between 1 and 6 at approximately 60 degrees C in [D6]benzene and all six species 1-6 were found in the equilibrium mixture. The relative stabilities of 1-6 were determined quantitatively by comparison of the observed molar ratios of 1-6 in equilibrium with calculated statistical molar ratios, and Ar2Tol3Sb (3) was found to be the most stable. The ligand-coupling reactions (LCRs) of 2-5 in solution were greatly accelerated by adding Cu(acac)2 or Li+TFPB- (TFPB: [3,5-(CF3)2 C6H3]4 B), whereby the rate becomes comparable to the LER. The use of flash vacuum thermolysis (FVT) allowed the LCR to occur with very little ligand-exchange; the exception ArTol4Sb had very fast ligand-exchange. The selectivities of the LCRs were calculated from the yield of the biaryls synthesized by using FVT. These results were highly consistent with reactions catalyzed in solution, in which bitolyl was not obtained at all. The experimental results suggested that the LCR of pentaarylantimony compounds proceeds in the manner of apical-apical coupling. 相似文献
118.
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120.
稀释剂粉末压片-X射线荧光光谱法测定锑矿石中锑及主量组分 总被引:1,自引:0,他引:1
利用X射线荧光光谱仪结合稀释剂粉末压片法来测定锑矿石中锑及主量组分。通过稀释剂的加入,减弱了样品的基体效应。人工配制了一系列具有浓度梯度的样品来解决标准样品个数偏少的问题。方法简便、实用,具有较高的精密度和准确度,测定结果满足实际工作需要。方法的相对标准偏差(RSD)为0.19%~2.0%,与常规分析结果基本一致。 相似文献