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81.
Hayashi H Nihashi W Umeyama T Matano Y Seki S Shimizu Y Imahori H 《Journal of the American Chemical Society》2011,133(28):10736-10739
Liquid crystalline donor (i.e., phthalocyanine) was covalently linked to acceptor (i.e, fullerene) to achieve efficient charge-transport properties in a liquid crystalline phase. The columnar structure exhibited highly efficient ambipolar charge-transport character, demonstrating the potential utility of the strategy in organic electronics. 相似文献
82.
Sequence‐Specific DNA Recognition by Cyclic Pyrrole–Imidazole Cysteine‐Derived Polyamide Dimers
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Makoto Yamamoto Dr. Toshikazu Bando Hironobu Morinaga Yusuke Kawamoto Kaori Hashiya Prof. Dr. Hiroshi Sugiyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):752-759
Pyrrole–imidazole (PI) polyamides bind to the minor groove of the DNA duplex in a sequence‐specific manner and thus have the potential to regulate gene expression. To date, various types of PI polyamides have been designed as sequence‐specific DNA binding ligands. One of these, cysteine cyclic PI polyamides containing two β‐alanine molecules, were designed to recognize a 7 bp DNA sequence with high binding affinity. In this study, an efficient cyclization reaction between a cysteine and a chloroacetyl residue was used for dimerization in the synthesis of a unit that recognizes symmetrical DNA sequences. To evaluate specific DNA binding properties, dimeric PI polyamide binding was measured by using a surface plasmon resonance (SPR) method. Extending this molecular design, we synthesized a large dimeric PI polyamide that can recognize a 14 bp region in duplex DNA. 相似文献
83.
84.
Zameer Shervani Yutaka Ikushima Masahiro Sato Hajime Kawanami Yukiya Hakuta Toshirou Yokoyama Takako Nagase Hironobu Kuneida Kenji Aramaki 《Colloid and polymer science》2008,286(4):403-410
We have employed a number of reducing and capping agents to obtain Ag(0) metallic nanoparticles of various sizes and morphologies.
The size and morphology were tuned by selecting reducing and capping agents. Spherical particles of 15 and 43 nm diameter
were obtained when 1 wt% aqueous starch solution of AgNO3 precursor salt was reduced by d(+)-glucose and NaOH, respectively, on heating at 70 °C for 30 min. Smaller size particles obtained in the case of d(+)-glucose reduction has been attributed to the slow reduction rate by mild reducing agent d(+)-glucose compared to strong NaOH. Conducting the reduction at ambient temperature of silver salt in liquid crystalline
pluronic P123 and L64 also gave spherical particles of 8 and 24 nm, respectively, without the addition of any separate reducing
agent. NaOH reduction of salt in ethylene glycol (11 g)/polyvinyl pyrolidone (PVP; 0.053 g) mixture produced large self-assembled
cubes of 520 nm when smaller (26–53 nm) star-shaped sharp-edged structures formed initially aggregated on heating the preparation
at 190 °C for 1 h. Increasing the amount of PVP (0.5 g) in ethylene glycol (11 g) and heating at 70 °C for 30 min yielded
a mixture of spherical and non-spherical (cubes, hexagons, pentagons, and triangle) particles without the addition of an extra
reducing agent. Addition of 5 wt% PVP to 1 wt% aqueous starched solution resulted in the formation of a mixture of spherical
and anisotropic structures when solution heated at 70 °C for 1 h. Homogeneous smaller sized (29 nm) cubes were synthesized
by NaOH reduction of AgNO3 in 12.5 wt% of water-soluble polymer poly(methyl vinyl ether) at ambient temperature in 30 min reaction time. 相似文献
85.
Hojo H Murasawa Y Katayama H Ohira T Nakahara Y Nakahara Y 《Organic & biomolecular chemistry》2008,6(10):1808-1813
Aryl thioesters of peptide segments were prepared by the conventional 9-fluorenylmethoxycarbonyl (Fmoc) strategy using a novel N-alkyl cysteine (NAC)-assisted thioesterification reaction. The peptide carrying NAC at its C-terminus was prepared by the Fmoc strategy and converted to the aryl thioester by 4-mercaptophenylacetic acid (MPAA) treatment without significant side reactions. The peptide thioester was used for the efficient preparation of 95-amino acid (AA) chemokine CCL27 by an Ag(+)-free thioester method. 相似文献
86.
Mutations detected in the p53 gene in human nonmelanoma skin cancers show a highly UV-specific mutation pattern, a dominance of C --> T base substitutions at dipyrimidine sites plus frequent CC --> TT tandem substitutions, indicating a major involvement of solar UV in the skin carcinogenesis. These mutations also have another important characteristic of frequent occurrences at CpG dinucleotide sites, some of which actually show prominent hotspots in the p53 gene. Although mammalian solar UV-induced mutation spectra were studied intensively in the aprt gene using rodent cultured cells and the UV-specific mutation pattern was confirmed, the second characteristic of the p53 mutations in human skin cancers had not been reproduced. However, studies with transgenic mouse systems developed thereafter for mutation research, which harbor methyl CpG-abundant transgenes as mutation markers, yielded complete reproductions of the situation of the human skin cancer mutations in terms of both the UV-specific pattern and the frequent occurrence at CpG sites. In this review, we evaluate the significance of the CpG methylation for solar UV mutagenesis in the mammalian genome, which would lead to skin carcinogenesis. We propose that the UV-specific mutations at methylated CpG sites, C --> T transitions at methyl CpG-associated dipyrimidine sites, are a solar UV-specific mutation signature, and have estimated the wavelength range effective for the solar-UV-specific mutation as 310-340 nm. We also recommend the use of methyl CpG-enriched sequences as mutational targets for studies on solar-UV genotoxicity for human, rather than conventional mammalian mutational marker genes such as the aprt and hprt genes. 相似文献
87.
Mizushima Takanori Thach Tran Thi Cam Wen Woo Jie Ohkita Hironobu 《Plasma Chemistry and Plasma Processing》2021,41(2):607-617
Plasma Chemistry and Plasma Processing - A porous membrane-like alumina (MA) tube was employed as a catalyst to improve the energy efficiency of the oxidative decomposition of low-concentrated... 相似文献
88.
Chemical Synthesis of O‐Glycosylated Human Interleukin‐2 by the Reverse Polarity Protection Strategy
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Dr. Yuya Asahina Shinobu Komiya Ami Ohagi Rina Fujimoto Dr. Hiroko Tamagaki Katsuhiro Nakagawa Dr. Takashi Sato Prof. Dr. Shizuo Akira Prof. Dr. Toshifumi Takao Dr. Akira Ishii Prof. Dr. Yoshiaki Nakahara Prof. Dr. Hironobu Hojo 《Angewandte Chemie (International ed. in English)》2015,54(28):8226-8230
The chemical synthesis of human interleukin‐2 (IL‐2) , having a core 1 sugar, by a ligation method is reported. Although IL‐2 is a globular glycoprotein, its C‐terminal region, in particular (99‐133), is extremely insoluble when synthesized by solid‐phase method. To overcome this problem, the side‐chain carboxylic acid of the Glu residues was protected by a picolyl ester, thus reversing its polarity from negative to positive. This reverse polarity protection significantly increased the isoelectric point of the peptide segment and made it positive under acidic conditions and facilitated the purification. An efficient method to prepare the prolyl peptide thioester required for the synthesis of the (28‐65) segment was also developed. These efforts resulted in the total synthesis of the glycosylated IL‐2 having full biological activity. 相似文献
89.
Goshima S Kanematsu M Matsuo M Murakami T Hori M Takamura M Kondo H Kako N Moriyama N Nakamura H Hoshi H 《Magnetic resonance imaging》2004,22(3):379-388
The purpose of our study was to assess whether respiratory-triggered multishot fast spin echo (MS-FSE) and breath-hold half-Fourier single-shot fast spin echo (SS-FSE) images, in addition to breath-hold T(2)*-weighted gradient recalled echo (GRE) images, increase observer performance in the detection of malignant hepatic tumors with ferumoxide-enhanced magnetic resonance (MR) imaging. Ferumoxide-enhanced MR images obtained from 48 patients with 83 malignant hepatic tumors were retrospectively reviewed by three independent off-site readers. In the first image review, GRE images alone were reviewed. Then, MS-FSE images were added for the first combination review. Finally, SS-FSE images were added for the second combination review. Observer performances were tested by McNemar's test and receiver-operating-characteristic analysis for the clustered data. Sensitivity for hepatocellular carcinomas, metastases, and malignant hepatic tumors overall was significantly (p < 0.05) higher with GRE and MS-FSE combined and GRE, MS-FSE and SS-FSE combined than with GRE alone. For metastases, the Az value was significantly (p < 0.05) higher with GRE and MS-FSE combined, and GRE, MS-FSE and SS-FSE combined than with GRE alone. We confirmed the incremental value of ferumoxide-enhanced MR imaging by obtaining MS-FSE and SS-FSE images in addition to GRE images in the detection of malignant hepatic tumors. 相似文献
90.
Hagiwara M Dohi M Nakahara Y Komatsu K Asahina Y Ueki A Hojo H Nakahara Y Ito Y 《The Journal of organic chemistry》2011,76(13):5229-5239
The biantennary complex-type N-glycans bearing LacNAc and LacdiNAc as the nonreducing end motif were synthesized in a protected form suitable to use in the Fmoc solid-phase peptide synthesis studies. Two approaches for the nonasaccharide synthesis were examined by taking advantage of the highly β-selective glycosylation with GlcNTCA (N-phenyl)trifluoroacetimidate. An earlier approach, which involved the reaction of the trisaccharide donor (Gal-GlcNTCA-Man) and trisaccharide acceptor (Man-GlcNPhth(2)-N(3)), produced a mixture of nonasaccharide isomers. On the other hand, mannosylation of the trisaccharide acceptor (Man-GlcNPhth(2)-N(3)) stereoselectively afforded the known pentasaccharide (Man(3)-GlcNPhth(2)-N(3)), which was reacted with the disaccharyl glycosyl donor (Gal-GlcNTCA or GalNTCA-GlcNTCA) to produce the desired nonasaccharide as a single stereoisomer. Selective dephthaloylation followed by N-acetylation furnished the GlcNAc(2) functionality. The resulting nonasaccharyl azides were condensed with Fmoc-Asp(OPfp)-OBu(t) or Fmoc-Asp(OPfp)-OPac in the presence of Ph(CH(3))(2)P and HOOBt. Finally, the Zn reduction and cleavage of the tert-butyl ester or Zn reduction alone produced the targeted nonasaccharyl Asn building blocks. 相似文献