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61.
刘士荣 《分子催化》2011,25(6):496-502
以SBA-15和氨基功能改性的SBA-15/NH2为载体,采用浸渍法制备了固载磷钨酸催化剂,通过FT—IR光谱,Raman光谱,XRD衍射分析,N2-吸附脱附实验,TEM和NH3-TPD等手段对催化剂进行表征.结果表明,磷钨酸在两种载体上均保持Keggin结构,载体的介孔结构没有明显破坏.在高固载量情况下,磷钨酸在SBA-15载体上发生晶相聚集,介孔孔道发生堵塞使比表面积、孔容和孔径明显减小.在SBA-15/NH2载体上,磷钨酸与载体发生酸碱作用,能够均匀分散于SBA-15/NH2的孔道中,但催化剂酸性有所降低.考察了相同固载量的两种催化剂对苹果酯合成反应的催化活性,结果表明,以SBA-15/NH2为载体的催化剂具有良好的重复使用性能.  相似文献   
62.
Degradable dendrimer‐like PEOs were designed using an original ABC‐type branching agent featuring a cleavable ketal group, following an iterative divergent approach based on the anionic ring opening polymerization (AROP) of ethylene oxide and arborization of PEO chain ends. A seventh generation dendrimer‐like PEO carrying 192 peripheral hydroxyls and exhibiting a molar mass of 446 kg · mol−1 was obtained in this way. The chemical degradation of these dendritic scaffolds was next successfully accomplished under acidic conditions, forming linear PEO chains of low molar mass (≈2 kg · mol−1), as monitored by 1H NMR, SEC, and MALDI‐TOF mass spectrometry as well as by AFM.

  相似文献   

63.
Metal complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) with a Schiff base derived from isatin and 2-amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene were synthesised and characterised by elemental analysis, conductance measurements, magnetic susceptibility, UV-Vis, IR, 1H NMR and EPR spectral studies. The spectral data revealed that the ligand acted as a neutral tridentate, coordinating to the metal ion through the azomethine nitrogen, ester carbonyl and carbonyl oxygen of the isatin moiety. The EPR spectral data indicated that metal-ligand bonds have considerable covalent character. The copper(II) complex was subjected to X-ray diffraction and cyclic voltammetric studies. The ligand and the metal complexes were screened for their antibacterial activity and it has been observed that the metal complexes are more potent bactericides than the ligand.  相似文献   
64.
研究实现了高对映选择性的硝基烷烃对N-Boc靛红亚胺1的不对称aza-Henry反应,来构建胺基季碳氧化吲哚. 发现在金鸡纳碱衍生的叔胺-酚羟基双功能催化剂C5的作用下,10种不同取代的N-Boc靛红亚胺与硝基甲烷的反应均能顺利进行,以66%~91%的对映选择性得到目标产物,产物的绝对构型通过X-ray单晶衍射加以确定. 硝基乙烷和硝基丙烷也能高对映选择性地参与反应,但非对映选择性不佳.  相似文献   
65.
Pd-mediated cycloisomerization of 3-C-propargyl-ribo- and allofuranose derivatives was investigated in detail to understand the influence of electronic factors on the regioselectivity (6-exo- vs 7-endo) of alkynol cycloisomerization leading either to a six- or seven-membered ring. In general, the 6-exo-dig mode of cyclization is facile and is independent of electronic factors. With some of the alkynols, a regioselective (7-endo?) hydration of the alkyne unit was observed and this has been attributed to the participation of C(3)-OH. When the C(3)-OH was protected as its benzyl ether, cycloisomerization of these alkynols occurred exclusively in a 6-exo-dig mode resulting in the corresponding [3.2.1]-bicyclic ketals. Additional control experiments conducted were in support of the participation of C(3)-OH in regioselective alkyne hydration.  相似文献   
66.
以二[(三甲基硅基)亚甲基]二氯化锡和三[(三甲基硅基)亚甲基]氯化锡为催化剂,通过苯乙酮和乙二醇合成苯乙酮环乙二缩酮的反应,探讨了含硅有机锡化合物的催化活性,并讨论了催化剂用量、溶剂、反应时间等因素对反应的影响。实验结果表明,含硅有机锡化合物是合成苯乙酮环乙二缩酮  相似文献   
67.
This article describes the synthesis, structural aspects and biological studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes of a new hydrazone derived from the condensation of isatin and 2‐aminobenzoylhydrazide. The ligand is well characterized using 1H NMR, 13C NMR, 2D HETCOR, mass and IR spectral studies. The chelating tendency of the ligand towards transition metal ions is established using analytical and spectral studies, which reveal the monobasic tridentate nature of the ligand. Octahedral geometry for Co(II), Cu(II) and Zn(II) and tetrahedral geometry for Ni(II) are tentatively proposed. All the synthesized compounds were screened for in vitro anticancer activity against Ehrlich ascites carcinoma and human cancer cell lines (adenocarcinoma HT29, kidney cancer cell line K293 and breast cancer cell line MDA231) using tryphan blue exclusion method and MTT assay. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
68.
报道了以2-甲(乙)基苯胺1a,1b为原料经Sandmeyer反应得到7-甲(乙)基靛红2a,2b;再以环境友好的聚乙二醇-400为溶剂,N-溴代丁二酰亚胺(NBS)为绿色溴代试剂对2a,2b进行5位溴代,得到5-溴-7-甲(乙)基靛红3a,3b;2a,2b,3a,3b进一步氮烃基化得到1-烃基-7-甲(乙)基靛红4a~4j和1-烃基-5-溴-7-甲(乙)基靛红5a~5j.2a,2b,3a,3b,4a~4j,5a~5j分别与硫代氨基脲,在以二氧六环为溶剂,碳酸钾存在的条件下回流反应,简便地合成了24种5H-[1,2,4]三嗪并[5,6-b]吲哚-3-硫醇类杂环化合物6a~6x.大部分化合物未见文献报道,其结构经红外光谱、质谱、核磁氢谱(碳谱)和元素分析确认.  相似文献   
69.
A simple and efficient approach for the construction of spirooxindole-pyrrolizidines and dispirooxindole-piperazines by cycloaddition reaction of azomethine ylide generated by isatin and proline has been demonstrated successfully. The formation of two different types of frameworks by two different modes of cycloaddition is explored. The developed protocol highlights simple reaction conditions, easy workup processes, and very good yields of products.  相似文献   
70.
以3-羟甲基色酮为原料,在4-二甲氨基吡啶催化下与(Boc)2O反应生成中间体A;A与靛红和脯氨酸生成的1,3-偶极子发生[3+2]环加成反应,合成了8个未见文献报道的多环吡咯并双螺环色满酮氧化吲哚类化合物(3a^3h),收率50%~67%,dr值4/1~2/1,其结构经^1H NMR,^13C NMR和HR-MS(ESI-TOF)表征。确定了化合物3a(CCDC:1973858)和3g(CCDC:1973859)的相对构型。结果表明:该类化合物含有连续5个立体中心,包括两个螺环季碳中心。  相似文献   
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