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101.
Utilization of Donor–Acceptor Interactions for the Catalytic Acceleration of Nucleophilic Additions to Aromatic Carbonyl Compounds 下载免费PDF全文
Tatsuhiro Uchikura Dr. Kosuke Ono Dr. Kohei Takahashi Prof. Nobuharu Iwasawa 《Angewandte Chemie (International ed. in English)》2018,57(8):2130-2133
A conceptually new method for the catalytic electrophilic activation of aromatic carbonyl substrates, by utilizing donor–acceptor interactions between an electron‐deficient macrocyclic boronic ester host ( [2+2] BTH‐F ) and an aromatic carbonyl guest substrate, was realized. In the presence of a catalytic amount of [2+2] BTH‐F , dramatic acceleration of the nucleophilic addition of a ketene silyl acetal towards either electron‐rich aromatic aldehydes or ketones was achieved. Several control experiments confirmed that inclusion of the aromatic substrates within [2+2] BTH‐F , through efficient donor–acceptor interactions, is essential for the acceleration of the reaction. 相似文献
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Ryosuke NAKANISHI Kosuke TAKEUCHI Kazunori AKIZUKI Ryoma NAKAGOSHI Hironobu KAKIHANA 《Physical Therapy Research》2020,23(2):195
Objective: Neuromuscular electrical stimulation (NMES) has been noted as an effective pre- contraction for an increase of neural and muscle factors during twitch contractions. However, it is unknown if this intervention is effective for the rate of force development (RFD), which is the ability to increase joint torque strength as quickly as possible, during tetanic contractions. NMES can be safely used by anyone, but, the strength setting of NMES requires attention so as not to cause pain. Therefore, the purpose of this study investigated whether NMES at less painful levels was effective for RFD during tetanic contractions. We also investigated effect activation by analyzing electromyogram (EMG) and RFD for each phase. Methods: Eighteen healthy males were studied. Before and after NMES intervention at 10% or 20% maximal voluntary isometric contraction (MVIC) level (10%NMES, 20%NMES respectively), EMG activity and the initial phase (30-, 50-, 100-, and 200-msec) RFD were measured. Visual analog scale (VAS) was also measured as an indicator of pain during each NMES. Results: 20%NMES increased EMG activity and 30-, 50-, and 100-msec of RFD during MVIC, but could not improve 200 msec of RFD. However, 10%NMES could be failed to increase all phases RFD, but VAS was lower than that of 20% NMES. Conclusion: These results suggest that muscle pre-contraction using 20%NMES could induce moderate pain, but could be an effective intervention to improve RFD via neural factor activity. 相似文献
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Dr. Ko Urushibara Dr. Yann Ferrand Prof. Zhiwei Liu Dr. Kosuke Katagiri Dr. Masatoshi Kawahata Estelle Morvan Ryan D'Elia Prof. Vojislava Pophristic Prof. Aya Tanatani Prof. Ivan Huc 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(43):11205-11215
The alkylation of some secondary amide functions with a dimethoxybenzyl (DMB) group in oligomers of 8-amino-2-quinolinecarboxylic acid destabilizes the otherwise favored helical conformations, and allows for cyclization to take place. A cyclic hexamer and a cyclic heptamer were produced in this manner. After DMB removal, X-ray crystallography and NMR show that the macrocycles adopt strained conformations that would be improbable in noncyclic species. The high helix folding propensity of the main chain is partly expressed in these conformations, but it remains frustrated by macrocyclization. Despite being homomeric, the macrocycles possess inequivalent monomer units. Experimental and computational studies highlight specific fluxional pathways within these structures. Extensive simulated annealing molecular dynamics allow for the prediction of the conformations for larger macrocycles with up to sixteen monomers. 相似文献
106.
Dr. Mari Takahara Dr. Rie Wakabayashi Naoki Fujimoto Dr. Kosuke Minamihata Prof. Masahiro Goto Prof. Noriho Kamiya 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(30):7315-7321
Lipid modification of proteins plays a significant role in the activation of cellular signals such as proliferation. Thus, the demand for lipidated proteins is rising. However, getting a high yield and purity of lipidated proteins has been challenging. We developed a strategy for modifying proteins with a wide variety of synthetic lipids using microbial transglutaminase (MTG), which catalyzes the cross-linking reaction between a specific glutamine (Q) in a protein and lysine (K) in the lipid-fused peptide. The synthesized lipid-G3S-MRHKGS lipid (lipid: fatty acids, tocopherol, lithocholic acid, cholesterol) was successfully conjugated to a protein fused with LLQG (Q-tagged protein) by an MTG reaction, yielding >90 % conversion of the Q-tagged protein in a lipidated form. The purified lipid–protein conjugates were used for labeling the cell membrane in vitro, resulting in best-anchoring ability of cholesterol modification. Furthermore, in situ cell-surface decoration with the protein was established in a simple manner: subjection of cells to a mixture of cholesterol-fused peptides, Q-tagged proteins and MTG. 相似文献
107.
Kosuke Makiguchi Seiya Kikuchi Kazuma Yanai Yoshitaka Ogasawara Shin‐ichiro Sato Toshifumi Satoh Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2014,52(7):1047-1054
The ring‐opening polymerizations (ROPs) of ε‐caprolactone (ε‐CL) and L ‐lactide (LLA) have been studied using the organocatalysts of diphenyl phosphate (DPP) and 4‐dimethylaminopyridine (DMAP). The “dual activation” property of DPP and the “bifunctional activation” property of DPP/DMAP were confirmed by the NMR measurement for ε‐CL and its chain‐end model of poly(ε‐caprolactone) and for LLA and its chain‐end model of poly(L ‐lactide) (PLLA), respectively. The molar ratio of DPP/DMAP was optimized as 1/2 for the ROP of LLA leading to the well‐defined PLLA, such as the molecular weight determined from 1H NMR measurement of 19,200 g mol?1 and the narrow polydispersity of 1.10. Additionally, functional initiators were utilized for producing the end‐functionalized PLLAs. The DPP‐catalyzed ROPs of ε‐CL and its analogue cyclic monomers and then the DPP/DMAP‐catalyzed ROP of LLA produced block copolymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1047–1054 相似文献
108.
Hiroyuki Hayashi Shota Katayama Rong Huang Kosuke Kurushima Isao Tanaka 《固体物理学:研究快报》2015,9(3):192-196
Undoped n‐ and p‐type tin monoxide (SnO) films have been selectively fabricated by pulsed laser deposition with a Sn target and careful control of oxygen partial pressure. The films are epitaxially grown in optimal growth conditions on yttria‐stabilized zirconia (YSZ) substrates with out‐of‐plane and in‐plane orientation relationships of (001)SnO//(001)YSZ and [110]SnO//[100]YSZ, respectively. Both Seebeck and Hall measurements show consistent results on the carrier types of the films. The electron Hall mobility is approximately 11 cm2/Vs at room temperature and the carrier activation energy is 0.14 eV for the n‐type film. The growth at increased oxygen partial pressure yields p‐type films, demonstrating the selective fabrication of both n‐ and p‐type SnO films without doping. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
109.
The angular and velocity distributions of desorbing product N(2) were examined over the crystal azimuth in steady-state NO+CO and N(2)O+CO reactions on Pd(110) by cross-correlation time-of-flight techniques. At surface temperatures below 600 K, N(2) desorption in both reactions splits into two directional lobes collimated along 41 degrees -45 degrees from the surface normal toward the [001] and [001] directions. Above 600 K, the normally directed N(2) desorption is enhanced in the NO reduction. Each product desorption component, as well as CO(2), shows a fairly asymmetric distribution about its collimation axis. Two factors, i.e., the anisotropic site structures and the reactant orientation and movements, are operative to induce such asymmetry, depending on the product emission mechanism. 相似文献
110.
The α‐oxo ketenes 6 which are generated by the pyrolysis of the 2‐aryl‐substituted 1,5,7‐trioxaspiro[2.5]octane‐4,8‐diones 1 , were reacted with Schiff bases 2 to give spiro compounds constructed between the β‐lactam and 1,3‐dioxolan‐4‐one; i.e., the 2,3,6‐triaryl‐2‐aza‐5,7‐dioxaspiro[3.4]octane‐1,8‐diones 3 and 4 . Hydrogenation of the mixture of 3a and 4a in the presence of catalytic amount of Pd‐C produced the trans‐2‐benzyloxy‐1,4‐diphenyl‐β‐lactam‐3‐carboxylic acid 9 . 相似文献