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1.
An automated on-line sample-preparation method using a computer-controlled pretreatment system (Auto-Pret AES system) coupled with ICP-AES was developed. In this work, an iminodiacetate chelating resin, packed in a mini-column and installed in the system was employed for the collection/concentration of 13 trace metals, including such toxic metals as Be, Cd, Cr, Cu and Pb. The limits of detection of the proposed method for trace metals were in the range of 0.001 (Be) -0.18 (Pb) ng mL-1. The enrichment factors for metal ions were about 19 times, when 5 mL of samples were used. The sample throughput was 11 h-1. The accuracy and the precision of the method were evaluated using river-water reference materials, SLRS-4 from NRCC, JSAC 0301-1 and JSAC 0302 from the Japan Society for Analytical Chemistry. The proposed method can be favorably applied to the collection/concentration of trace metals in natural water samples. 相似文献
2.
Ingrid Fischler Rosi Wagner Ernst A.Koerner Von Gustorf 《Journal of organometallic chemistry》1976,112(2):155-165
The photochemical reaction of the trinuclear complex Fe3(CO)10NSi(CH3)3 under hydrogen leads to substitution of the bridging carbonyl group by two hydrogens. The resulting complex H2Fe3(CO)9NSi(CH3)3 acts as a catalyst in the photochemical hydrogenation of olefins and dienes. 相似文献
3.
Zachary M. Schulte Yeon Hye Kwon Yi Han Chong Liu Lin Li Yahui Yang Austin Gamble Jarvi Sunil Saxena Gtz Veser J. Karl Johnson Nathaniel L. Rosi 《Chemical science》2020,11(47):12807
Metal–organic frameworks constructed from multiple (≥3) components often exhibit dramatically increased structural complexity compared to their 2 component (1 metal, 1 linker) counterparts, such as multiple chemically unique pore environments and a plurality of diverse molecular diffusion pathways. This inherent complexity can be advantageous for gas separation applications. Here, we report two isoreticular multicomponent MOFs, bMOF-200 (4 components; Cu, Zn, adeninate, pyrazolate) and bMOF-201 (3 components; Zn, adeninate, pyrazolate). We describe their structures, which contain 3 unique interconnected pore environments, and we use Kohn–Sham density functional theory (DFT) along with the climbing image nudged elastic band (CI-NEB) method to predict potential H2/CO2 separation ability of bMOF-200. We examine the H2/CO2 separation performance using both column breakthrough and membrane permeation studies. bMOF-200 membranes exhibit a H2/CO2 separation factor of 7.9. The pore space of bMOF-201 is significantly different than bMOF-200, and one molecular diffusion pathway is occluded by coordinating charge-balancing formate and acetate anions. A consequence of this structural difference is reduced permeability to both H2 and CO2 and a significantly improved H2/CO2 separation factor of 22.2 compared to bMOF-200, which makes bMOF-201 membranes competitive with some of the best performing MOF membranes in terms of H2/CO2 separations.Tailorable multicomponent MOFs and MOF membranes for efficient H2/CO2 separation. 相似文献
4.
K. Rosi ReddyCh. Venkateshwar Reddy M. MaheshP.V.K. Raju V.V. Narayana Reddy 《Tetrahedron letters》2003,44(44):8173-8175
N-Butyl-N,N-dimethyl-α-phenylethylammonium bromide catalyzes efficiently the three component condensation reaction of an aromatic aldehyde, a β-keto ester and urea/thiourea under solvent free conditions at 100°C to afford the corresponding dihydropyrimidinone in high yield. 相似文献
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6.
Mariangela Potenza Giuseppina Sabatino Francesca Giambi Luca Rosi Anna Maria Papini Luigi Dei 《Analytical and bioanalytical chemistry》2013,405(2-3):691-701
The chemical analysis of egg-based wall paintings—the mezzo fresco technique—is an interesting topic in the characterisation of organic binders. A revised procedure for a dot-enzyme-linked immunosorbent assay (dot-ELISA) able to detect protein components of egg-based wall paintings is reported. In the new dot-ELISA procedure we succeeded in maximizing the staining colour by adjusting the temperature during the staining reaction. Quantification of the colour intensity by visible reflectance spectroscopy resulted in a straight line plot of protein concentration against reflectance in the wavelength range 380–780 nm. The modified dot-ELISA procedure is proposed as a semi-quantitative analytical method for characterisation of protein binders in egg-based paintings. To evaluate its performance, the method was first applied to standard samples (ovalbumin, whole egg, egg white), then to model specimens, and finally to real samples (Giotto’s wall paintings). Moreover, amino acid analysis performed by innovative ultra-performance liquid chromatography was applied both to standards and to model samples and the results were compared with those from the dot-ELISA tests. In particular, after protein hydrolysis (24 h, 114 °C, 6 mol L?1 HCl) of the samples, amino acid derivatization by use of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate enabled reproducible analysis of amino acids. This UPLC amino acid analysis was rapid and reproducible and was applied for the first time to egg-based paintings. Because the painting technique involved the use of egg-based tempera on fresh lime-based mortar, the study enabled investigation of the effect of the alkaline environment on egg-protein detection by both methods. Figure
Model wall paintings specimens and typical dot-ELISA stains for egg proteins. 相似文献
7.
Emília Valena Ferreira de Arago Luca Mancini Noelia Faginas-Lago Marzio Rosi Dimitrios Skouteris Fernando Pirani 《Molecules (Basel, Switzerland)》2022,27(7)
The reaction between the cyano radical CN and cyanoacetylene molecule HCN is of great interest in different astronomical fields, from star-forming regions to planetary atmospheres. In this work, we present a new synergistic theoretical approach for the derivation of the rate coefficient for gas phase neutral-neutral reactions. Statistic RRKM calculations on the Potential Energy Surface are coupled with a semiempirical analysis of the initial bimolecular interaction. The value of the rate coefficient for the HCN + CN → H + NCCCCN reaction obtained with this method is compared with previous theoretical and experimental investigations, showing strengths and weaknesses of the new presented approach. 相似文献
8.
9.
Metal(II) Ion Complexes with 5‐(Pyrazin‐2‐yl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione; Synthesis,Structural Characterization,Acid‐base,and Complexing Properties in Solution
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Aleksander Kufelnicki Jolanta Jaciubek‐Rosińska Marta Sobiesiak Agata Paneth Julia Jezierska Elzbieta Budzisz 《无机化学与普通化学杂志》2017,643(16):1067-1074
The study reports the synthesis of complexes Co(HL)Cl2 ( 1 ), Ni(HL)Cl2 ( 2 ), Cu(HL)Cl2 ( 3 ), and Zn(HL)3Cl2 ( 4 ) with the title ligand, 5‐(pyrazin‐2‐yl)‐1,2,4‐triazole‐5‐thione (HL), and their characterization by elemental analyses, ESI‐MS (m/z), FT‐IR and UV/Vis spectroscopy, as well as EPR in the case of the CuII complex. The comparative analysis of IR spectra of the metal ion complexes with HL and HL alone indicated that the metal ions in 1 , 2 , and 3 are chelated by two nitrogen atoms, N(4) of pyrazine and N(5) of triazole in the thiol tautomeric form, whereas the ZnII ion in 4 is coordinated by the non‐protonated N(2) nitrogen atom of triazole in the thione form. pH potentiometry and UV/Vis spectroscopy were used to examine CoII, NiII, and ZnII complexes in 10/90 (v/v) DMSO/water solution, whereas the CuII complex was examined in 40/60 (v/v) DMSO/water solution. Monodeprotonation of the thione triazole in solution enables the formation of the L:M = 1:1 species with CoII, NiII and ZnII, the 2:1 species with CoII and ZnII, and the 3:1 species with ZnII. A distorted tetrahedral arrangement of the CuII complex was suggested on the basis of EPR and Vis/NIR spectra. 相似文献
10.
The “one-pot” homogeneous hydrogenation of γ-butyrolactone and succinic or fumaric acid to 1,4-butandiol, have been successfully realized in the presence of the catalytic system [Ru(acac)3]/triphos] [triphos:MeC(CH2PPh2)3]. The influence of some reaction parameters on the regioselectivity and the rate of the reaction were investigated. The study was then extended to the “one-pot” synthesis of isotopomeric 1,4-butandiols by deuteration of the appropriate substrates in a deuterated solvent. 1,4-butandiol-d8, which was fully characterized, was obtained with 96% yield and 100% isotopomeric selectivity. A mechanism was proposed to rationalize the role of catalyst, solvent and deuterium distribution. 相似文献