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排序方式: 共有339条查询结果,搜索用时 31 毫秒
171.
Daisuke Kawaguchi Ayumi Kodama Naoko Abe Kei Takebuchi Fumitaka Hashiya Fumiaki Tomoike Kosuke Nakamoto Yasuaki Kimura Yoshihiro Shimizu Hiroshi Abe 《Angewandte Chemie (International ed. in English)》2020,59(40):17403-17407
Messenger RNAs (mRNAs) with phosphorothioate modification (PS‐mRNA) to the phosphate site of A, G, C, and U with all 16 possible combinations were prepared, and the translation reaction was evaluated using an E. coli cell‐free translation system. Protein synthesis from PS‐mRNA increased in 12 of 15 patterns when compared with that of unmodified mRNA. The protein yield increased 22‐fold when the phosphorothioate modification at A/C sites was introduced into the region from the 5′‐end to the initiation codon. Single‐turnover analysis of PS‐mRNA translation showed that phosphorothioate modification increases the number of translating ribosomes, thus suggesting that the rate of translation initiation (rate of ribosome complex formation) is positively affected by the modification. The method provides a new strategy for improving translation by using non‐natural mRNA. 相似文献
172.
Koji Numasawa Kenjiro Hanaoka Naoko Saito Yoshifumi Yamaguchi Takayuki Ikeno Honami Echizen Masahiro Yasunaga Toru Komatsu Tasuku Ueno Masayuki Miura Tetsuo Nagano Yasuteru Urano 《Angewandte Chemie (International ed. in English)》2020,59(15):6015-6020
Folate receptors (FRs) are membrane proteins involved in folic acid uptake, and the alpha isoform (FR‐α) is overexpressed in ovarian and endometrial cancer cells. For fluorescence imaging of FRs in vivo, the near‐infrared (NIR) region (650–900 nm), in which tissue penetration is high and autofluorescence is low, is optimal, but existing NIR fluorescent probes targeting FR‐α show high non‐specific tissue adsorption, and require prolonged washout to visualize tumors. We have designed and synthesized a new NIR fluorescent probe, FolateSiR‐1 , utilizing a Si‐rhodamine fluorophore having a carboxy group at the benzene moiety, coupled to a folate ligand moiety through a negatively charged tripeptide linker. This probe exhibits very low background fluorescence and afforded a tumor‐to‐background ratio (TBR) of up to 83 in FR‐expressing tumor‐bearing mice within 30 min. Thus, FolateSiR‐1 has the potential to contribute to the research in the field of biology and the clinical medicine. 相似文献
173.
Dr. Léa Delacour Dr. Naoko Kotera Dr. Ténin Traoré Sébastien Garcia‐Argote Céline Puente Dr. François Leteurtre Dr. Edmond Gravel Dr. Nawal Tassali Dr. Céline Boutin Estelle Léonce Dr. Yves Boulard Dr. Patrick Berthault Dr. Bernard Rousseau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6089-6093
We describe the synthesis of a highly water‐soluble cryptophane 1 that can be seen as a universal platform for the construction of 129Xe magnetic resonance imaging (MRI)‐based biosensors. Compound 1 is easily functionalized by Huisgen cycloaddition and exhibits excellent xenon‐encapsulation properties. In addition, 1 is nontoxic at the concentrations typically used for hyperpolarized 129Xe MRI. 相似文献
174.
175.
Yoshitake M Nohta H Sejima N Todoroki K Yoshida H Yamaguchi M 《Analytical and bioanalytical chemistry》2011,399(4):1665-1675
In this paper we introduce a novel approach for highly selective and sensitive analysis of cysteines (glutathione, cysteine, and homocysteine). This method is based on the detection of intramolecular fluorescence resonance energy transfer (FRET) in a liquid chromatography (LC) system after double-labeling of the amino and sulfhydryl groups of the cysteines. In this detection process, we monitored the FRET between the amine-derivatized and thiol-derivatized fluorophores. We screened 16 combinations of fluorescent reagents. As a result, FRET occurred most effectively when the sulfhydryl and amino groups of the cysteines were derivatized with 7-diethylamino-3-[{4'-(iodoacetyl)amino}phenyl]-4-methylcoumarin (DCIA, Ex/Em 390/480 nm) and 4-fluoro-7-nitrobenz-2-oxo-1,3-diazole (NBD-F, Ex/Em 480/540 nm), respectively, in this order. The double-labeled cysteines emitted NBD-F fluorescence (540 nm) through an intramolecular FRET process when they were excited at the wavelength of maximum excitation of DCIA (390 nm). The generation of FRET was confirmed by comparison with analysis of n-amylamine or tryptophan (amines without a sulfhydryl group) and 6-mercaptohexanol (thiol without an amino group) performed using LC and a three-dimensional fluorescence detection system. We were able to separate the double-labeled cysteines (DCIA and NBD-F) when performing LC on an ODS column with isocratic elution. The limits of quantification (signal-to-noise ratio = 10) and detection (signal-to-noise ratio = 3) for the cysteines, for a 20-μL injection volume, were in the range 150-670 fmol and 46-200 fmol, respectively. The sensitivity of the intramolecular FRET-forming derivatization method is higher than that of a system which takes advantage of conventional detection of the derivatives. Furthermore, this method provides sufficient selectivity and sensitivity to determine the total cysteines present in the plasma of healthy humans. 相似文献
176.
Hifumi E Takao S Fujimoto N Uda T 《Journal of the American Chemical Society》2011,133(38):15015-15024
It has long been an important issue to produce a catalytic antibody that possesses the ability to lose the infectivity of a bacteria or virus. The monoclonal antibody JN1-2 was generated using a synthetic peptide (TGLRNGITNKVNSVIEKAA) conjugated with human IgG. The peptide sequence includes the conserved region of the hemagglutinin molecule (HA(1) and HA(2) domains), which locates on the envelope of the influenza virus and plays an important role in influenza A virus infection. The monoclonal antibody specifically reacted with the HA2 domain, not only of H2 but also of an H1 strain of the H1N1 subtype (H1 strain). The heavy chain (JN1-2-H) isolated from the parent antibody showed catalytic activity cleaving the above antigenic peptide with very high turnover (kcat = 26 min(-1)), and it could slowly degrade the recombinant HA(2) domain by the catalytic function. Interestingly, the heavy chain exhibited the ability to reduce the infectivity of type A H1N1 but not type B, indicating specificity to type A. This characteristic monoclonal catalytic antibody heavy chain could suppress the infection of the influenza virus in vitro assays. 相似文献
177.
Naoko Oono Masato Sagawa Ryuta Kasada Hideki Matsui Akihiko Kimura 《Journal of magnetism and magnetic materials》2011,323(3-4):297-300
A novel grain boundary diffusion (GBD) treatment with a Dy–Ni–Al eutectic alloy powder allowed Dy to penetrate into sintered plates of Nd–Fe–B magnet as thick as 5 mm. The coercivity of the magnet was increased from a value of 1160 kA/m (14.5 kOe) to 1760 kA/m (22 kOe). This was achieved without any marked decrease in remanance and with a high squareness. 相似文献
178.
d-cycloserine (CS) is transformed into cis-3, 6-bis(aminooxymethyl)-2, 5-piperazinedione (CS-dimer) in the solid state under a humid atmosphere. This dimerization process was followed by measuring the IR bands characteristic of CS and CS-dimer. The reaction was accelerated by the presence of increased water vapor. The X-ray analysis of CS monohydrate (CS · H2O) revealed that the CS molecules exist as a zwitter ion where the α-amino N atom is protonated and the amide N atom is deprotonated in the crystal. Participation of water molecules was suggested in the dimerization of CS. 相似文献
179.
Dr. Kazuteru Usui Nozomi Narita Ryosuke Eto Seika Suzuki Atsushi Yokoo Dr. Kosuke Yamamoto Prof. Dr. Kazunobu Igawa Naoko Iizuka Yuki Mimura Dr. Tomohiro Umeno Shota Matsumoto Dr. Masashi Hasegawa Prof. Dr. Katsuhiko Tomooka Prof. Dr. Yoshitane Imai Prof. Dr. Satoru Karasawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(65):e202202922
Small chiral organic molecules with CD properties are in high demanded due to their potential use in promising electronic and biological applications. Herein, we reveal a system in which the oxidation of a phosphino group to the corresponding phosphine oxide on the inner rim of a helicene derivative induces a CPL response. Laterally π-extended 7,8-dihydro[5]helicenes bearing phosphine and phosphine oxide groups on their inner helical rims (i. e., the C1 position) were synthesized, and their helical structures were unambiguously determined by X-ray crystallography. The photophysical (UV/visible and emission) and chiroptical properties of these compounds were investigated in various solvents. Despite their structural similarities, phosphine oxide showed a significantly better CPL response than phosphine, with a high dissymmetry factor for emission (|glum|=(1.3–1.9)×10−3) that can be attributed to structural changes in the interior of the helicene helix. 相似文献
180.
Nobuhiro Oya Shunsuke Saitoh Yukiko Furuhashi Naoko Yoshie 《Journal of polymer science. Part A, Polymer chemistry》2012,50(10):1926-1932
Semicrystalline network polymers were obtained by the Diels–Alder (DA) reaction of furyl‐telechelic poly(ε‐caprolactone) and tris(2‐maleimide ethyl)amine. Controlling the rates of crystallization and crosslinking reaction gave materials with various properties. Curing at a temperature much below Tm of poly(ε‐caprolactone), at which crystallization proceeded first followed by DA reaction, gave a hard and stiff material, whereas curing above Tm gave a soft and stretchable one. When crystallization and crosslinking were promoted simultaneously, tough and ductile materials were obtained. Structural analysis of the network polymers showed that the variation in the properties was derived from the difference in the crystallinity, crystallite size, and network structure. Therefore, materials with various mechanical properties, from soft to hard, could be obtained by simple thermal treatment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献