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Influence of the Absolute Configuration of NPE‐Caged Cytosine on DNA Single Base Pair Stability 下载免费PDF全文
Dipl.‐Chem. Hannah S. Steinert Dipl.‐Chem. Florian Schäfer Dr. Hendrik R. A. Jonker Prof. Dr. Alexander Heckel Prof. Dr. Harald Schwalbe 《Angewandte Chemie (International ed. in English)》2014,53(4):1072-1075
Photolabile protecting groups are a versatile tool to trigger reactions by light irradiation. In this study, we have investigated the influence of the absolute configuration of the 1‐(2‐nitrophenyl)ethyl (NPE) cage group on a 15‐base‐pair duplex DNA. Using UV melting, we determined the global stability of the unmodified and the selectively (S)‐ and (R)‐NPE‐modified DNA sequences, respectively. We observe a differently destabilizing effect for the two NPE stereoisomers on the global stability. Analysis of the temperature dependence of imino proton exchange rates measured by NMR spectroscopy reveals that this effect can be attributed to decreased base pair stabilities of the caged and the 3′‐neighbouring base pair, respectively. Furthermore, our NMR based structural models of the modified duplexes provide a structural basis for the distinct effect of the (S)‐ and the (R)‐NPE group. 相似文献
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Sulfoxides ( 1 and 10 ) gave oxidation-reduction products when treated with 5N hydrochloric acid. 8-Methoxy-3-(methylsulfinyl)-4H-benzopyran-4-one (1) gave 8-methoxy-3-(methylthio)-4H-1-benisopyran-4-one ( 4 ) and 8-methoxy-3-(methylsulfonyl)-4H-1-benzopyran-4-one ( 5 ), whereas 1-melhyl-3-(methylsulfinyl)-4(1H)quinolinone ( 10 ) gave 1-methyl-3-(methylthio)-4(1H)-quinolinone ( 12 ) and 1-methyl-4(1H)-quinolinone ( 13 ). 相似文献
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"Caged" derivatives of a 15 nucleotide ssDNA anti-thrombin aptamer have been synthesized in which thymidine nucleotides are modified with photolabile protecting groups. One caged thymidine in a key location is enough to completely mask the aptamer's function in respect to their affinity for thrombin and their inhibition of the blood clotting cascade. With light (366 nm) the caging group can be removed, yielding the unmodified active aptamer. 相似文献
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Nikolai Grebenovsky Larita Luma Patricia Müller Prof. Dr. Alexander Heckel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(53):12298-12302
Oligonucleotide-based therapeutics have made rapid progress in clinical treatment of a variety of disease indications. Since most therapeutic oligonucleotides serve more than just one function and tend to have a prolonged lifetime, spatio-temporal control of these functions would be desirable. Photoswitches like azobenzene have proven themselves as useful tools in this matter. Upon irradiation, the photoisomerization of the azobenzene moiety causes destabilization in adjacent base pairs, leading to a decreased hybridization affinity. Since the way the azobenzene is incorporated in the oligonucleotide is of utmost importance, we synthesized locked azobenzene C-nucleosides and compared their photocontrol capabilities to established azobenzene C-nucleosides in oligonucleotide test-sequences by means of fluorescence-, UV/Vis-, and CD-spectroscopy. 相似文献
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Chemo‐Enzymatic Synthesis of Position‐Specifically Modified RNA for Biophysical Studies including Light Control and NMR Spectroscopy 下载免费PDF全文
Sara Keyhani Thomas Goldau Anja Blümler Prof. Dr. Alexander Heckel Prof. Dr. Harald Schwalbe 《Angewandte Chemie (International ed. in English)》2018,57(37):12017-12021
The investigation of non‐coding RNAs requires RNAs containing modifications at every possible position within the oligonucleotide. Here, we present the chemo‐enzymatic RNA synthesis containing photoactivatable or 13C,15N‐labelled nucleosides. All four ribonucleotides containing ortho‐nitrophenylethyl (NPE) photocages, photoswitchable azobenzene C‐nucleotides and 13C,15N‐labelled nucleotides were incorporated position‐specifically in high yields. We applied this approach for the synthesis of light‐inducible 2′dG‐sensing riboswitch variants and detected ligand‐induced structural reorganization upon irradiation by NMR spectroscopy. This chemo‐enzymatic method opens the possibility to incorporate a wide range of modifications at any desired position of RNAs of any lengths beyond the limits of solid‐phase synthesis. 相似文献