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961.
Dr. Kazuya Matsuo Yuki Nishikawa Marie Masuda Prof. Itaru Hamachi 《Angewandte Chemie (International ed. in English)》2018,57(3):659-662
The development of bioorthogonal approaches for labeling of endogenous proteins under the multimolecular crowding conditions of live cells is highly desirable for the analysis and engineering of proteins without using genetic manipulation. N‐Sulfonyl pyridone (SP) is reported as a new reactive group for protein sulfonylation. The ligand‐directed SP chemistry was able to modify not only purified proteins in vitro, but also endogenous ones on the surface of and inside live cells selectively and rapidly, which allowed to convert endogenous proteins to FRET‐based biosensors in situ. 相似文献
962.
A Bioanode Using Thermostable Alcohol Dehydrogenase for an Ethanol Biofuel Cell Operating at High Temperatures 下载免费PDF全文
Aya Kontani Miyuki Masuda Hirotoshi Matsumura Nobuhumi Nakamura Masafumi Yohda Hiroyuki Ohno 《Electroanalysis》2014,26(4):682-686
To extend the range of biofuel cell applications, we wish to increase their maximum operational temperatures. Using a thermostable alcohol dehydrogenase as a biocatalyst, we prepared an enzyme‐immobilized bioanode that can operate at high temperatures. The catalytic current for ethanol oxidation was increased using this electrode at temperatures up to 80 °C. 相似文献
963.
M Maeda S Sasaki T Fukumura E Fukuzawa K Watanabe M Kojima T Tahara K Masuda Y Ichiya 《Chemical & pharmaceutical bulletin》1992,40(7):1793-1798
N-Fluoroalkyl and 4-fluoropyrrolidinyl eticlopride analogues with high affinity toward central nervous system dopamine D2 receptors in vitro were labelled with positron emitting fluorine-18 (t1/2 = 110 min), and their in vivo biodistribution was investigated in rats. N-[18F]Fluoro-ethyl and -propyl eticlopride derivatives showed poor in vivo selectivity in the rat brain. On the other hand, 4-[18F]fluoropyrrolidinyl eticlopride exhibited almost constant and relatively high striatal concentration. The striatal/cerebellar radioactivity ratio, which corresponds to the ratio of a brain D2 receptor-rich to poor region, gradually increased to 5.2-6.4, 90 min after the injection. The striatal accumulation was selectively inhibited by pre-injection of haloperidol, a dopamine D2 antagonist, without affecting accumulation in other tissues. Thus, the selective striatal accumulation of 4-[18F]fluoropyrrolidinyl eticlopride in striatal tissue appears to be due to the specific binding to dopamine D2 receptors. 相似文献
964.
Hiroyuki?Kogure Sunao?Nanami Yuka?Masuda Yoshiharu?Toyama Kenji?KubotaEmail author 《Colloid and polymer science》2005,283(11):1163-1171
Thermal response of N-isopropylacrylamide (NiPAM) gel particles of submicron size was investigated by means of ultrasonic velocity and density
focusing on the hydration and dehydration behavior. Hydration number, defined as the number of water molecules bound to one
NiPAM monomer unit, was quantitatively evaluated in the course of the volume phase transition. Hydration numbers at low and
high temperatures were about 7.5 (20 °C) and 3 (40 °C), respectively. Hydration number decreases markedly near the volume
phase transition temperature, and the decrease is responsible to the formation of hydrophobic bonding and dehydration. The
hydration number is independent both of the size and the composition of gel particles in the shrunken state, although there
exists a composition dependence in the swollen state. It was also found that the self-assemblies formed by hydrophobic interaction
are more bulky compared to those in the hydrated state. 相似文献
965.
Hiraishi T Masuda E Miyamoto D Kanayama N Abe H Maeda M 《Macromolecular bioscience》2011,11(2):187-191
We recently discovered that poly(aspartate) (PAA) hydrolase‐1 from Pedobacter sp. KP‐2 has a unique property of specifically cleaving the amide bond between β‐aspartate units in thermally synthesized PAA (tPAA). In the present study, the enzymatic synthesis of poly(α‐ethyl β‐aspartate) (β‐PAA) was performed by taking advantage of the substrate specificity of PAA hydrolase‐1. No polymerization of diethyl L ‐aspartate by native PAA hydrolase‐1 occurred because of the low dispersibility of the enzyme in organic solvent. Poly(ethylene glycol) (PEG) modification of the enzyme improved its dispersibility and enabled it to polymerize the monomer substrate. MALDI‐TOF MS analysis showed that the synthesized polymer was observed in the range of m/z = 750–2 500. This analysis also revealed that the polymer was composed of ethyl aspartate units, containing either an ethyl ester or a free carboxyl end group at its carboxyl terminus. 1H NMR analysis demonstrated that the synthesized polymer consisted of only β‐amide linkages. Thus, the present results indicate that PAA hydrolase‐1 modified with PEG is useful for the synthesis of β‐PAA due to its unique substrate specificity and good dispersibility in organic solvent.
966.
Ogo S Yamahara R Roach M Suenobu T Aki M Ogura T Kitagawa T Masuda H Fukuzumi S Watanabe Y 《Inorganic chemistry》2002,41(21):5513-5520
In our preliminary communication (Ogo, S.; Wada, S.; Watanabe, Y.; Iwase, M.; Wada, A.; Harata, M.; Jitsukawa, K.; Masuda, H.; Einaga, H. Angew. Chem., Int. Ed. 1998, 37, 2102-2104), we reported the first example of X-ray analysis of a mononuclear six-coordinate (hydroxo)iron(III) non-heme complex, [Fe(III)(tnpa)(OH)(RCO(2))]ClO(4) [tnpa = tris(6-neopentylamino-2-pyridylmethyl)amine; for 1, R = C(6)H(5)], which has a characteristic cis (hydroxo)-Fe(III)-(carboxylato) configuration that models the cis (hydroxo)-Fe(III)-(carboxylato) moiety of the proposed (hydroxo)iron(III) species of lipoxygenases. In this full account, we report structural and spectroscopic characterization of the cis (hydroxo)-Fe(III)-(carboxylato) configuration by extending the model complexes from 1 to [Fe(III)(tnpa)(OH)(RCO(2))]ClO(4) (2, R = CH(3); 3, R = H) whose cis (hydroxo)-Fe(III)-(carboxylato) moieties are isotopically labeled by (18)OH(-), (16)OD(-), (18)OD(-), (12)CH(3)(12)C(18)O(2)(-), (12)CH(3)(13)C(16)O(2)(-), (13)CH(3)(12)C(16)O(2)(-), (13)CH(3)(13)C(16)O(2)(-), and H(13)C(16)O(2)(-). Complexes 1-3 are characterized by X-ray analysis, IR, EPR, and UV-vis spectroscopy, and electrospray ionization mass spectrometry (ESI-MS). 相似文献
967.
S. M. Abdul Karim Ryoji Nomura Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2002,40(14):2458-2463
Acetylenes containing salicylideneaniline groups—N‐salicylidene‐3‐ethynylaniline ( 1 ), N‐(3‐t‐butylsalicylidene)‐3‐ethynylaniline ( 2 ), and N‐(3‐t‐butylsalicylidene)‐4‐ethynylaniline ( 3 )—polymerized smoothly and gave yellow to red polymers in excellent yields when a rhodium catalyst was employed. Polymers with alkyl substituents on the aromatic rings [poly( 2 ) and poly( 3 )] were soluble in CHCl3, tetrahydrofuran, and so forth, whereas the polymer without alkyl substituents [poly( 1 )] was insoluble in any solvent. N‐(3‐t‐Butylsalicylidene)propargylamine did not provide any polymer. Thermogravimetric analyses of the resultant polymers exhibited good thermal stability (To, onset temperature of weight loss > 300 °C). The ultraviolet–visible spectra of the polymers showed absorption maxima and cutoff wavelengths around 360 and 520 nm, respectively. The polymers exhibited largely Stokes‐shifted fluorescence (emission wavelength ? 550 nm) upon photoexcitation at 350 nm, which resulted from the photoinduced intramolecular proton transfer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2458–2463, 2002 相似文献
968.
Yuji Suzuki Masashi Shiotsuki Dr. Fumio Sanda Prof. Dr. Toshio Masuda Prof. Dr. 《化学:亚洲杂志》2008,3(12):2075-2081
Optically active 1‐methylpropargyl esters bearing various substituents were polymerized with [(nbd)Rh]+[η6‐C6H5B(C6H5)3]? (nbd=norbornadiene) as a catalyst to afford the corresponding poly(1‐methylpropargyl ester)s with moderate molecular weights in good yields. The polymers have a cis‐stereoregular structure, which was determined by 1H NMR spectroscopy. Large optical rotations and clear CD signals demonstrated that all these polymers take on a helical structure with a predominantly one‐handed screw sense. The polymers exhibited large viscosity indices in the range 1.14–1.75. Chiral amplification was observed in R/S copolymerization. Conformational analysis revealed that the polymers form a tightly twisted helical structure with a dihedral angle of 70° at the single bond of the main chain. 相似文献
969.
Tsuda M Oguchi K Iwamoto R Okamoto Y Kobayashi J Fukushi E Kawabata J Ozawa T Masuda A Kitaya Y Omasa K 《The Journal of organic chemistry》2007,72(12):4469-4474
A potent cytotoxic 20-membered macrolide, iriomoteolide-1a (1), has been isolated from a benthic dinoflagellate Amphidinium sp. (strain HYA024), and the structure was elucidated on the basis of detailed analyses of 2-D NMR data. The relative and absolute stereochemistries were assigned by the combination of conformational analyses using NMR data and modified Mosher's method of 1. 相似文献
970.