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11.
硝基酚类化合物在海水中的光化学氧化研究 总被引:11,自引:0,他引:11
酚类化合物尤其是硝基苯酚属于国家严格控制排放的有毒物质 .由于工业排污等原因 ,在近岸水体中能检测到许多酚类化合物 .我国胶州湾和杭州湾表层海水中酚的含量分别高达 3和 9mg/L[1] .酚的毒性会影响海水生物的生长和繁殖 ,危及人类健康 .由于硝基苯酚难于生化降解 ,因此研究其在水体中的光降解十分重要 [2~ 6 ] .文献中关于有机污染物的光化学研究大多侧重于废水处理 ,且降解方法也多采用 Ti O2 催化降解 [7,8] .对于硝基苯酚在天然水体中的光降解则知之甚少 .本文通过模拟海水条件下硝基苯酚的光化学反应及其影响因素 ,更加深入地了… 相似文献
12.
本文用自旋捕捉技术与ESR方法研究了五种硝基芴酮与五种不同的伯、仲、叔脂肪胺的光化夺氢反应中的活泼自由基。结果表明,当胺中有N上氢和α—C上氢时,优先形成N—中心自由基:仅当无N上氢时,才形成C—中心自由基。 相似文献
13.
N-取代酰胺-二苯酮体系光化夺氢反应活泼自由基的ESR研究 总被引:3,自引:2,他引:1
本文用自由基捕捉剂2,3,5,6-四甲基亚硝基苯(ND)及苯亚甲基叔丁基氮氧化物(PBN)与ESR相结合的方法研究了十二种取代酰胺RC6H4NHC(0)CH3(R-CH3、Cl、Br、H、NO2)、C6H5N(R)C(0)CH3(R=CH3、C2H5)及HC(0)NR2(R-CH3、C2H5)与二苯酮光化夺氢反应中的活泼自由基。结果表明:
1.对于RC6H4NHC(0)CH3,二苯酮夺取氮上H形成R-C6H4NC(0)CH3自由基。
2.对C6H5N(R)C(0)CH3及HC(O)NR2,二苯酮夺取与羰基相连的甲基氢、羰基上氢及与N相连碳上的氢分别形成
C6H5N(R)C(0)CH2、C(0)NR2、C6H5N(CHR')C(0)CH3及。 相似文献
14.
本文报道了二苯胺、甲基苯基胺、甲潜苄胺、二苄胺、二异丙胺和二乙胺分别与苯并呋咱-1-氧化物在紫外光照下发生光化学反应的电子自旋共振(ESR)研究结果。结果表明:紫外光的作用首先使苯并呋咱-1-氧化物处于激发态,它与二胺作用生成激基态络合物,经氧转移和二胺的氮氢键断裂而最终生成相应的氮氧自由基。 相似文献
15.
An expedient route to tetracyclo[6.5.2.02,7.09,13]pentadec-2(7),11-dien-14-one and tetracyclic framework of conidiogenol have been reported. Cycloaddition of annulated cyclohexa-2,4-dienone with cyclopentadiene, photochemical oxa-di-π-methane reaction and a highly unusual dehalogenation of bridgehead halogen are the key features of our methodology. 相似文献
16.
A new method was proposed for the accurate determination of mercury in cosmetic samples based on isotopic dilution (ID)-photochemical vapor generation (PVG)-inductively coupled plasma mass spectrometry (ICP MS) measurement. Cosmetic samples were directly dissolved in formic acid solution and subsequently subjected to PVG for the reduction of mercury into vapor species following by ICP MS detection. Therefore, the risks of analyte contamination and loss were avoided. Highly enriched 201Hg isotopic spike is added to cosmetics and the isotope ratios of 201Hg/202Hg were measured for the quantitation of mercury. With ID calibration, the influences originating from sample matrixes for the determination of mercury in cosmetic samples have been efficiently eliminated. The effects of several experimental parameters, such as the concentration of the formic acid, and the flow rates of carrier gas and sample were investigated. The method provided good reproducibility and the detection limits were found to be 0.6 pg mL−1. Finally, the developed method was successfully applied for the determination of mercury in six cosmetic samples and a spike test was performed to verify the accuracy of the method. 相似文献
17.
Photochemical degradation of environmentally persistent perfluorooctanoic acid (PFOA) in the presence of Fe(Ⅲ) 总被引:1,自引:0,他引:1
Yuan Wang~ 《中国化学快报》2008,19(3):371-374
Environmentally persistent and bioaccumulative perfluorooctanic acid (PFOA) was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe(Ⅲ), 80% of PFOA with initial concentration of 48μmol/L (20 mg/L) was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe(Ⅲ) initiated degradation of PFOA irradiated with 254 nm UV light. 相似文献
18.
Micro-flow photochemical reactions have great advantage over batch photochemical reactions due to its high light-penetration efficiency. Integrated micro-flow reaction enables efficient synthesis of structurally complex compounds from simple starting materials and it can avoid handling of explosive, toxic, unstable, or odorous intermediates. Combination of micro-flow photochemical reactions with integrated micro-flow synthesis enhances their benefits. Here we summarize recently reported integrated multi-step micro-flow synthesis containing various photochemical reactions. 相似文献
19.
Marijana Hranjec Gordana Pavlović Marinela Marinović Grace Karminski-Zamola 《Structural chemistry》2008,19(2):353-359
Substituted 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole derivatives 2, 3 and 6 were synthesized. 2-(2-Pyridin-4-yl-vinyl)-1H-benzimidazole 2 and 6-methyl-2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 3 were prepared by condensation reaction from 3-pyridin-4-yl-acrylic acid and corresponding 1,2-phenylenediamines in polyphosporic
acid (PPA). 2,7,11-b-Triaza-benzo[c]fluorene 4 was prepared by photochemical dehydrocyclization reaction of ethanolic solution of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 2. 2-(2-Pyridin-4-yl-vinyl)-3H-benzimidazole-6-carbonitrile 6 was prepared by condensation reaction from 3-pyridin-4-yl-propenal and 4-cyano-1,2-phenylenediamine using p-benzoquinone as oxidants. The structure of novel benzimidazole derivatives has been studied by 1H and 13C NMR, IR, MS, UV/Vis and fluorescence spectroscopy. The structure of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 2 was confirmed by X-ray single crystal structure analysis. The conformation of the molecule is E in regard to substituents position around vinyl double C=C bond. The non-planar molecules are mutually connected via the
N–H···N and C–H···N type of intermolecular hydrogen bonds into infinite chains spreading along y axis. 相似文献
20.
Jan Hajduch 《Journal of fluorine chemistry》2008,129(9):807-810
We report a new synthesis of enantiomerically pure (S)-4-fluorohisitidine based on diastereoselective alkylation of MOM-protected 4-fluoro-5-bromomethyl imidazole using the Schöllkopf bis-lactim amino acid synthesis. Improvements in procedures for preparation of key intermediates are also described. (S)-4-Fluorohisitidine prepared by this new method was identical in all respects to material prepared by previous procedures. 相似文献