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991.
J.-M. Kim, S. Bae and I.-S. Lee showed that there exists an isomorphism between the p-primary part of the ideal class group and p-primary part of the unit group modulo cyclotomic unit group in Q+(ζpn) for all sufficiently large n under some conditions. In the present paper, we shall give an analogue of their result for modular units. 相似文献
992.
Reaction of sulfamide with ethoxymethylene derivatives yielded 4-ethoxycarbonyl-, 4-cyano-, and 4-nitro-2H,6H-1,2,6-thiadiazine 1,1-dioxide. In some cases, the corresponding open chain sulfamidomethylene derivatives were isolated. Preparation of 4-amino- and 4-amino-5-methyl-2H,6H-1,2,6-thiadiazin-3-one 1,1-dioxide is also described. Reaction of sulfamide with ethyl 3,3-ethoxypropionate afforded 3,7-bis(etlioxycarbonylmethyl)perhydro-1,5,2,4,6,8-dithiatetra-zocine 1,1,5,5-tetroxide. 相似文献
993.
Tsuyoshi Tanaka Mina Okochi Shugo Watanabe Tadashi Matsunaga 《Analytica chimica acta》2009,638(2):186-7290
An on-chip type cation-exchange chromatography system with electrochemical detection of HbA1c, which is one of the most important diabetes marker protein, was developed using ferrocene-conjugated anti-human hemoglobin (Hb) monoclonal antibody (FcAb). The FcAb was used as an electrochemical probe for the detection of each Hb. The system contains syringe pump, on-chip type cation-exchange column consisted of PDMS and cation-exchange resin beads, and a three-electrode flow-cell system. The separation conditions of HbA1c in blood calibrator samples from other Hbs, e.g. HbA0, HbA1a or HbA1b, were optimized using the on-chip type system. The electrochemical oxidation current from FcAb reacting with each Hb was measured at 350 mV (vs. Ag/AgCl). Hbs including HbA1a and HbA1b, HbA1c and HbA0 fractions were eluted in this order. A linear relationship between HbA1c levels and electrochemical oxidation currents was obtained in the range from 4.0% to 12.6% HbA1c. All procedure including antigen-antibody reaction was completed in 15 min. Furthermore, a good correlation was obtained between KO500 method (HPLC) and our proposed method. These results indicate that the on-chip type system with electrochemical detection can be applied to a novel POCT device for rapid and precise detection of HbA1c. 相似文献
994.
Sign Reversal of a Large Circularly Polarized Luminescence Signal by the Twisting Motion of a Bidentate Ligand 下载免费PDF全文
Dr. Junpei Yuasa Hiroshi Ueno Prof. Dr. Tsuyoshi Kawai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8621-8627
This work demonstrates sign reversal of large circularly polarized luminescence (CPL) signal based on the hinge‐like twisting motion of a bidentate ligand, 3,3‐bis(diphenylphosphoryl)‐2,2‐bipyridine (BIPYPO), in a cis–trans isomerization of chiral europium(III) complexes. X‐ray diffraction analysis revealed that twisting motion of BIPYPO provides s‐cis and s‐trans geometries of a chiral EuIII complex containing either tris[3‐(trifluoromethylhydroxymethylene)‐(+)‐camphorate] (D ‐ 1 ) or tris[3‐(heptafluoropropylhydroxymethylene)‐(+)‐camphorate] (D ‐ 2 ). The s‐cis EuIII complexes show eight‐coordinate geometry around the EuIII ion, in which the chelate between the phosphoryl oxygen and the EuIII ion forces the s‐cis geometry of BIPYPO. In contrast, the phosphorus–nitrogen interaction provides a conformational lock for the s‐trans geometry of the BIPYPO ligand, inducing a quasi‐seven‐coordinate EuIII complex. The difference in coordination geometry causes the sign change of the CPL signals between the s‐cis and s‐trans isomers, whereby the s‐cis and s‐trans isomers of EuIII complexes exhibit the positive and negative CPL signals, respectively, for the 5D0→7F1 transition. The proportion of the s‐trans‐D ‐ 1 against s‐cis‐D ‐ 1 increases upon changing the solvent from [D3]acetonitrile to [D6]acetone, inducing a sign change of the CPL signals. The complexes D ‐ 1 and D ‐ 2 show a biexponential decay with two different lifetimes, suggesting two emitting species, that is, the s‐cis and s‐trans isomers of EuIII complexes. In both cases, the proportions of the longer lifetime components (τ1) decrease and instead the shorter lifetime components (τ2) increase upon changing the solvent from [D3]acetonitrile to [D6]acetone. 相似文献
995.
Dr. Florie Lavigne Dr. Aimée El Kazzi Yannick Escudié Dr. Eddy Maerten Dr. Tsuyoshi Kato Dr. Nathalie Saffon‐Merceron Prof. Vicenç Branchadell Prof. Fernando P. Cossío Dr. Antoine Baceiredo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12528-12536
The synthesis of a novel family of cyclic push–pull carbenes, namely, azavinylidene phosphoranes, is described. The methodology is based on a formal [3+2] cycloaddition between terminal alkynes and phosphine–imines followed by an oxidation/deprotonation step. Carbenes 6 , obtained by simple deprotonation, exhibit typical transient carbene reactivity like the intramolecular C?H insertion reaction and a pronounced ambiphilic character exemplified by [2+1] cycloaddition with electron‐poor methyl acrylate. Owing to the cyclic structure, carbenes 6 also exhibit an excellent coordination ability toward transition metals. RhI complex 10 was obtained in excellent yield and was fully characterized by multinuclear NMR spectroscopy and X‐ray crystallography. The corresponding RhI–carbonyl complex was also prepared; this indicates that carbenes 6 belong to the strongest σ‐donating ligands to date. DFT calculations confirmed the high σ‐donation ability of 6 and their classification as push–pull carbenes with a relatively small singlet–triplet energy gap of 23.2–24.3 kcal mol?1. 相似文献
996.
New bioanalytical methods have been developed for the determination of imidafenacin (KRP-197/ONO-8025, IM), a novel antimuscarinic drug developed for the treatment of overactive bladder, and its metabolites, M-2, M-3, M-4, M-6 and M-8 (method 1), M-5 and M-9 (method 2) in human urine by using liquid chromatography-tandem mass spectrometry. In each method, the urine sample was extracted by solid-phase extraction, separated on a semi-micro high-performance liquid chromatography column using gradient elution and detected by tandem mass spectrometer with an atmospheric pressure chemical ionization or ionspray interface. Extraction recoveries of IM and metabolites were 81.4% or more. Calibration curves had good linearity in the concentration ranges 0.2-50 ng/mL for IM, M-2, M-3, M-4, M-6 and M-8 (method 1) and 1-250 ng/mL for M-5 and M-9 (method 2), respectively. The accuracy and precision in the intra-day and inter-day reproducibility tests were within +/-17.0 and 16.1% at the lowest concentrations, and within +/-12.8 and 11.1% at higher concentrations, respectively. Using these analytical methods, excretion profiles of IM and its metabolites in human urine were successfully determined after oral administration of IM at the therapeutic dosage of 0.1 mg. 相似文献
997.
Palladium(II) complexes with a tetradentate pseudo-tripodal ligand having two phosphino groups and two phosphine sulfide or selenide groups, pp3X2 (pp3 = tris[2-(diphenylphosphino)ethyl]phosphine, X = S (1) or Se (2)), were prepared from [PdCl(pp3)]Cl. Both of these phosphine chalcogenide complexes 1 and 2 showed rapid equilibrium between the five-coordinate [PdCl(pp3X2)]Cl with two bound phosphine chalcogenide groups and four-coordinate [PdCl2(pp3X2)] with two dissociated pendant ones in chloroform. The thermodynamic parameters for the reaction, [PdCl(pp3X2)]+ + Cl−?[PdCl2(pp3X2)], were obtained by low-temperature 31P NMR as follows: K298 = 3.7 × 103 and 5.4 × 102 mol−1, ΔH° = 11.3 ± 0.3 and 13.4 ± 0.4 kJ mol−1, and ΔS° = 106 ± 2 and 97 ± 2 J mol−1 K−1 for 1 and 2, respectively. The rate for the geometrical change at 246.7 K for 1 was appreciably faster than that for 2. These thermodynamic and kinetic results indicate that the phosphine selenide Se atoms can stabilize the five-coordinate structure by effective π-back donation from Pd(II) compared with the phosphine sulfide S atoms. Difference in retention of the catalytic activity for Suzuki coupling, 2 > 1 > [PdCl(pp3 or p3)]Cl, was explained by difference in the π-accepting ability that stabilizes the catalytically active Pd(0) species. Considering the rapid dissociation-coordination equilibrium of the phosphine chalcogenide groups on Pd(II), it is probable that the oxidative addition and the subsequent transmetallation of the Pd(II) species are hardly blocked by the phosphine chalcogenide groups. 相似文献
998.
Dr. Masahiro Kawada Mr. Ryo Tsuyusaki Dr. Kosuke Nakashima Dr. Hiroshi Akutsu Dr. Shin-ichi Hirashima Prof. Takashi Matsumoto Dr. Hikaru Yanai Prof. Tsuyoshi Miura 《化学:亚洲杂志》2021,16(16):2272-2275
An improved diaminomethylenemalononitrile organocatalyst, bearing a N,N-disubstituted structure, promoted enantioselective conjugate addition reaction of α-branched aldehydes with vinyl sulfone, affording adducts with excellent enantioselectivities (up to 96% ee). Mechanistic studies revealed that the diaminomethylenemalononitrile motif holds the vinyl sulfone substrate using a single hydrogen bond accompanied by multiple weak interactions, including electrostatic C−H⋅⋅⋅O interactions. 相似文献
999.
Terashima T Kamigaito M Baek KY Ando T Sawamoto M 《Journal of the American Chemical Society》2003,125(18):5288-5289
Star polymers containing ruthenium complex in the core were prepared by ruthenium-catalyzed living radical polymerization, where the metal catalysts were directly encapsulated on linking reactions of living poly(MMA) in the presence of ethylene glycol dimethacrylate as a linker and diphenyl-4-styrylphosphine as a ligand incorporated in the core. The products were characterized by SEC/MALLS, UV-vis, NMR, AFM, TEM, and ICP-AES and were employed as polymer catalysts for the oxidation reaction of alcohol. 相似文献
1000.
A facile and stereocontrolled construction of optically active pyrazinoisoquinoline skeletons based on tandem cyclization of enantiopure phenylalanine derivatives was examined. The reaction provided optically active 6,11b-trans pyrazinoisoquinoline ring systems in excellent diastereoselectivity, and this method was applicable to the cyclization of phenylalanine derivatives with diverse substituents. 相似文献