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排序方式: 共有146条查询结果,搜索用时 15 毫秒
51.
Thalhammer A Mecinović J Loenarz C Tumber A Rose NR Heightman TD Schofield CJ 《Organic & biomolecular chemistry》2011,9(1):127-135
Based on structural analysis of the human 2-oxoglutarate (2OG) dependent JMJD2 histone N(ε)-methyl lysyl demethylase family, 3-substituted pyridine 2,4-dicarboxylic acids were identified as potential inhibitors with possible selectivity over other human 2OG oxygenases. Microwave-assisted palladium-catalysed cross coupling methodology was developed to install a diverse set of substituents on the sterically demanding C-3 position of a pyridine 2,4-dicarboxylate scaffold. The subsequently prepared di-acids were tested for in vitro inhibition of the histone demethylase JMJD2E and another human 2OG oxygenase, prolyl-hydroxylase domain isoform 2 (PHD2, EGLN1). A subset of substitution patterns yielded inhibitors with selectivity for JMJD2E over PHD2, demonstrating that structure-based inhibitor design can enable selective inhibition of histone demethylases over related human 2OG oxygenases. 相似文献
52.
Molecular approaches towards mixed metal oxides and their behaviour in mixed oxide support Au catalysts for CO oxidation 总被引:1,自引:0,他引:1
Geserick J Fröschl T Hüsing N Kucerova G Makosch M Diemant T Eckle S Behm RJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(13):3269-3286
We herein report a water-based sol-gel approach towards porous mixed Si/Ti oxides using co-precipitated glycol-modified precursors. By adjusting synthesis parameters such as the pH value and the Si/Ti ratio of the precursor, the morphology as well as the Si/Ti-composition of the resulting mixed oxide particles can be varied in a wide range. The behaviour of the mixed oxides as substrates for Au catalysts and the performance of the resulting catalysts in the CO oxidation reaction was investigated and compared to catalysts supported on mesoporous anatase and rutile synthesized analogously. For comparable Au particle sizes and Au loadings, the composition of the mixed oxide support was found to significantly affect the reactivity and reaction behaviour, with mixed oxide supported Au catalysts synthesized at pH=5 or 10 and with a Si/Ti-ratio of 1:19 and 1:34 exhibiting the maximum activity. In contrast to the enhanced activity, the mixed oxide supports do not lead to a significant improvement in deactivation behaviour and catalyst stability. 相似文献
53.
Hamed RB Henry L Gomez-Castellanos JR Mecinović J Ducho C Sorensen JL Claridge TD Schofield CJ 《Journal of the American Chemical Society》2012,134(1):471-479
The biocatalytic versatility of wildtype and engineered carboxymethylproline synthases (CMPSs) is demonstrated by the preparation of functionalized 5-carboxymethylproline derivatives methylated at C-2, C-3, C-4, or C-5 of the proline ring from appropriately substituted amino acid aldehydes and malonyl-coenzyme A. Notably, compounds with a quaternary center (at C-2 or C-5) were prepared in a stereoselective fashion by engineered CMPSs. The substituted-5-carboxymethyl-prolines were converted into the corresponding bicyclic β-lactams using a carbapenam synthetase. The results demonstrate the utility of the crotonase superfamily enzymes for stereoselective biocatalysis, the amenability of carbapenem biosynthesis pathways to engineering for the production of new bicyclic β-lactam derivatives, and the potential of engineered biocatalysts for the production of quaternary centers. 相似文献
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Christoph Schoo Sebastian Bestgen Alexander Egeberg Jasmin Seibert Sergey N. Konchenko Claus Feldmann Peter W. Roesky 《Angewandte Chemie (International ed. in English)》2019,58(13):4386-4389
Zintl phases of arsenic and molecular compounds containing Zintl‐type polyarsenide ions are of fundamental interest in basic and applied sciences. Unfortunately, the most obvious and reactive arsenic source for the preparation of defined molecular polyarsenide compounds, yellow arsenic As4, is very inconvenient to prepare and neither storable in pure form nor easy to handle. Herein, we present the synthesis and reactivity of elemental As0 nanoparticles (As0Nano, d=7.2±1.8 nm), which were successfully utilized as a reactive arsenic source in reductive f‐element chemistry. Starting from [Cp*2Sm] (Cp*=η5‐C5Me5), the samarium polyarsenide complexes [(Cp*2Sm)2(μ‐η2:η2‐As2)] and [(Cp*2Sm)4As8] were obtained from As0nano, thereby generating the largest molecular polyarsenide of the f‐elements and circumventing the use of As4 in preparative chemistry. 相似文献
56.
The catalytic hydrogenation of CO2 includes the dissociation of hydrogen and further reaction with CO2 and intermediates. We investigate how the amount of hydrogen in the bulk of the catalyst affects the hydrogenation reaction taking place at the surface. For this, we developed an experimental setup described herein, based on a magnetic suspension balance and an infrared spectrometer, and measured pressure-composition isotherms of the Pd−H system under conditions relevant for CO2 reduction. The addition of CO2 has no influence on the measured hydrogen absorption isotherms. The pressure dependence of the CO formation rate changes suddenly upon formation of the β-PdH phase. This effect is attributed to a smaller surface coverage of hydrogen due to repulsive electronic interactions affecting both bulk and surface hydrogen. 相似文献
57.
Kalpani K. Somarathne Jordan A. J. McCone Amira Brackovic Jos Luis Pinedo Rivera J. Robin Fulton Euan Russell Jessica J. Field Christopher L. Orme Hedley L. Stirrat Jasmin Riesterer Paul H. Teesdale‐Spittle John H. Miller Joanne E. Harvey 《化学:亚洲杂志》2019,14(8):1230-1237
The fungal metabolite TAN‐2483B has a 2,6‐trans‐relationship across the pyran ring of its furo[3,4‐b]pyran‐5‐one core, which has thwarted previous attempts at its synthesis. We have now developed a chiral pool approach to this core and prepared side‐chain analogues of TAN‐2483B. The synthesis relies on ring expansion of a reactive furan ring‐fused dibromocyclopropane and alkynylation of the resulting pyran. The furan ring is constructed by palladium‐catalysed carbonylative lactonisation. Various side‐chains are appended through Wittig‐type chemistry. The prepared analogues showed micromolar activity towards cancer cell lines HL‐60, 1A9 and MCF‐7 and certain human disease‐relevant kinases, including Bruton's tyrosine kinase (Btk). 相似文献
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60.
Papsai P Snygg AS Aldag J Elmroth SK 《Dalton transactions (Cambridge, England : 2003)》2008,(38):5225-5234
Nuclear DNA is a well characterized target for many low molecular metal-based drugs, with cisplatin and related antineoplastic compounds as typical examples. Much less is known concerning to what extent targeting of RNA may influence the activity spectrum of these types of drugs. In a preliminary communication by us (Papsai et al., Dalton Trans., 2006, 3515) we were able to show that the folded, three-dimensionally well defined structure of tRNA(Ala) readily interacts with cisplatin. In the present study we have further analyzed the binding preferences within the preferentially targeted stem region (sMh(Ala)) by modulation of the sequence around the G-U wobble base-pair and the net charge of the 3' and 5' ends. Our data show that the adduct profile is strongly influenced by the presence of the 5' end phosphate group. Further, the adduct formation reaction can be prevented by replacement of the G-U wobble base-pair with the fully complementary G-C pair. To further investigate the influence from local sequence on the platination process, a model of the anticodon region (acMh(Ala)) was also investigated. In the absence of consecutive guanine-residues in the stem- and anticodon regions, preferential platination was found to take place at the terminal AG-site in the stem region. However, after introduction of a GG-pair in the anticodon loop, platination was observed also here. At 37 degrees C, pH 6.3 and C(Pt) = 0.10 mM the rate of platination was determined to be ca. 1 x 10(-4) s(-1), with the most rapid reaction observed for interaction with the anticodon model carrying two adjacent guanines in the single-stranded loop. Together, these data show that platination of RNA is highly sequence- and structure-dependent. 相似文献