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排序方式: 共有139条查询结果,搜索用时 15 毫秒
1.
Jong Chan Lee Jin Young Park So Young Yoon Yong Hun Bae Seung Jun Lee 《Tetrahedron letters》2004,45(1):191-193
A novel and direct method for the synthesis of α-halocarbonyl compounds using sequential treatment of carbonyl compounds with [hydroxy(tosyloxy)iodo]benzene followed by magnesium halides under solvent-free microwave irradiation conditions is described. 相似文献
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Whereas tropinone derived nonaflate 3 was no suitable precursor for Heck-reactions, the related carbamate 7 was an excellent substrate for palladium-catalyzed processes. Nonaflate 7 was either isolated in excellent yield by LDA treatment of ketone 5 followed by trapping with NfF (nonafluorobutanesulfonyl fluoride) or generated in situ by fluoride-catalyzed reaction of silyl enol ether 6 with NfF. The desired 1,3-diene 8 was prepared by conventional Heck-reaction of nonaflate 7 with methyl acrylate in almost quantitative yield. Alternatively, the one-pot nonaflation-Heck protocol starting from silyl enol ether 6 provided 8 in good yield. The couplings of acrylonitrile or phenyl vinyl sulfone were also performed with in situ generated 7 and they afforded the expected 1,3-dienes 9 and 10 in good yields. The Sonogashira-reaction with phenylacetylene also started from silyl enol ether 6 and provided enyne 11 via 7 in good yield. A Diels-Alder reaction of 1,3-diene 8 with N-phenyl maleimide at 100 °C furnished tetracyclic adduct 12 in good yield, with excellent diastereofacial selectivity, but with low endo-exo-selectivity. Nonaflate 14 was easily obtained from the corresponding unsaturated bicyclic ketone 13. It behaved differently in an attempted Heck-reaction and mainly led to fragmentation products 15 and 16, whereas the expected 1,3-diene 17 was formed only as minor component. However, 14 could successfully be used in a Sonogashira-reaction with phenylacetylene to afford compound 18. These transformations demonstrate the great potential of tropinone derived alkenyl nonaflates for diversity oriented syntheses of interesting compounds containing an 8-azabicyclo[3.2.1]octane scaffold. 相似文献
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L. C. Machado A. A. L. Marins E. J. B. Muri J. A. S. Lacerda V. O. Balthar P. F. Fulvio J. C. C. Freitas 《Journal of Thermal Analysis and Calorimetry》2004,75(2):615-621
This paper presents the reactions of synthesis between the ligand sodium diphenylamine-4-sulfonate and the lanthanum(III)
chloride hydrated. The compounds (LaCl3)2·(C12H10NSO3Na)3·2(CH3CH2OH) (A) and (LaCl3)·(C12H10NSO3Na)·(CH3CH2OH)·12H2O (B) were obtained using the solvents ethanol and methanol (synthesis A) and ethanol and water (synthesis B). The produced
compounds and the ligand were characterized by thermogravimetric and differential thermogravimetric analysis, IR spectroscopy
and elemental analysis of sodium, carbon, hydrogen, nitrogen, sulfur, chlorine and lanthanum, whereas the residues from thermal
decomposition were investigated by X-ray diffractometry.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Alkylsulfonates from methanesulfonic acid to decanesulfonic acid were separated by isotachophoresis with conductivity detection in a common electrolyte system at pH 4.8. The electrolyte system consisted of 10 mM HCl buffered with epsilon-aminocaproic acid (pH 4.8) and 0.1% methylhydroxyethylcellulose (MHEC) acting as the leading electrolyte. The terminating electrolyte was 20 mM caproic acid also containing 0.05% MHEC. Current settings of 250 microA for the first and 50 microA for the second capillary were applied. On one hand, the method was applied to the determination of the content of methanesulfonate as the salt forming agent (mesilate) in a recently registered drug substance. The results obtained by ITP were compared with an orthogonal titration method. On the other hand, due to the column-coupling configuration of the electrophoretic instrument, the method could be extended to the trace determination in the ppm range in order to monitor methanesulfonic acid as an impurity in a drug substance. The validation confirmed the linearity of the method between 1 and 10 mg/l, limits of detection and quantification below 1 mg/l, recovery rates from 92.4 to 95.4%, and repeatability with a R.S.D. of 3.8% (six runs with a 4 mg/l spiked sample). Finally, three batches of a newly produced drug substance could be checked for methanesulfonic acid giving results of below 0.0014% (concentration related to the drug substance). 相似文献
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Crystal structure of meso‐substituted pyrazolyl porphyrin complexes and their highly active catalyst for oxidation of alkylbenzenes 下载免费PDF全文
During the past few years, a great deal of effort has been devoted to the anchoring of catalytic oxidation. In this work, three new catalysts CuPp, MnPp and ZnPp by solvothermal methods with 5, 10, 15, 20‐tetrakis(4‐N‐pyrazolyl)‐phenyl porphyrin (H2Pp) and the corresponding metal salts have been synthesized and structurally characterized. The single crystal structures determined by X‐ray diffraction show the bond distances of M‐N in porphyrin cores determined the conformation of porphyrin rings. We explored the catalytic activity of CoPp, CuPp, MnPp and ZnPp for oxidation of alkylbenzenes. The experimental results display these products exhibit high catalytic activities and selectivities for oxidation of ethylbenzene to acetophenone, and can be reused by filtration without appreciable decrease in catalytic activity and selectivity. 相似文献
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Dr. Madleen Busse Iman Trinh Prof. Peter C. Junk Assoc. Prof. Richard L. Ferrero Prof. Philip C. Andrews 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(17):5264-5275
The synthesis and characterisation of nine new tris‐substituted bismuth(III) aminoarenesulfonates of the general formula [Bi(O3S‐RN)3] (RN=o‐aminophenyl 1 , m‐aminophenyl 2 , 6‐amino‐3‐methoxyphenyl 3 , p‐aminophenyl 4 , 2‐pyridyl 5 , o‐aminonaphthyl 6 , 5‐aminonaphthyl 7 , 4‐amino‐3‐hydroxynaphthyl 8 and 5‐isoquinolinyl 9 ) is described. Two synthetic strategies, using Ag2O and [Bi(OtBu)3], were explored and compared. The possibility to access heteroleptic bismuth(III) complexes with the new silver(I) metathesis reaction is demonstrated with the synthesis of the heteroleptic bismuth(III) aminoarenesulfonate complexes [PhBi(O3S‐P2)2(dmso)] 10 , [Ph2Bi(O3S‐P2)]∞ 11 and [PhBi(O3S‐P2)2]∞ 12 , of which the solid state structures 10 and 12 are presented (2P‐SO3?=2‐pyridinesulfonate). These complexes offer remarkable in‐vitro activity against three standard laboratory strains of Helicobacter pylori (H. pylori) as demonstrated by their exceptionally low minimum inhibitory concentration (MIC) values of 0.049 μg mL?1 for the strains 251 and B128, which places most MIC values in the nano‐molar region. These results demonstrate the importance of the amino functionality in addition to the sulfonate group on the bactericidal properties against H. pylori. 相似文献
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高效液相色谱-串联质谱法测定泡沫灭火材料及其他材料中的全氟辛烷磺酸及其盐 总被引:1,自引:0,他引:1
建立了一种高效液相色谱-串联质谱(HPLC-MS/MS)测定泡沫灭火材料、洗涤剂以及织物整理剂中全氟辛烷磺酸及其盐(PFOS)的方法。对应产品中的PFOS用水超声提取后,经固相萃取柱淋洗萃取,萃取液以乙腈-10 mmol/L乙酸铵溶液(80:20, v/v)为流动相进行HPLC分离,在负离子模式和多级反应监测(MRM)方式下进行测定。用两个子离子的相对丰度定性,外标法定量。PFOS的测定在0.002~0.1 mg/L范围内线性关系良好(r2=0.998);泡沫灭火材料、洗涤剂以及织物整理剂中PFOS的加标回收率分别为93.4%~103%, 93.2%~102%和91.8%~102%,精密度(以相对标准偏差(RSD)计)分别为0.48%~3.52%, 0.78%~1.79%和0.47%~3.47%;方法的检出限均为2 mg/kg(0.0002%)(信噪比(S/N)≥10),满足欧盟法规对泡沫灭火材料、洗涤剂以及织物整理剂中PFOS的限量检测要求。该方法准确度和灵敏度高,前处理简单,可用于泡沫灭火材料、洗涤剂以及织物整理剂中PFOS的检测。 相似文献