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111.
Shoji T Ito S Toyota K Yasunami M Morita N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(27):8398-8408
Mono-, bis-, tris-, and tetrakis(1-azulenylethynyl)benzene and mono- and bis(1-azulenylethynyl)thiophene derivatives 5-10 have been prepared by Pd-catalyzed alkynylation of ethynyl arenes with 1-iodoazulene derivative or the 1-ethynylazulene derivative with tetraiodobenzene and iodothiophenes under Sonogashira-Hagihara conditions. Compounds 5-10 reacted with tetracyanoethylene in a [2+2] cycloaddition reaction to afford the corresponding 1,1,4,4,-tetracyano-2-(5-isopropyl-3-methoxycarbonyl-1-azulenyl)-3-butadienyl chromophores 12-16 in excellent yields, except for the reaction of the tetrakis(1-azulenylethynyl)benzene derivative. 1,1,4,4,-Tetracyano-2,3-bis(1-azulenyl)butadiene (17) was also prepared by the similar reaction of bis(1-azulenyl)acetylene (11) with tetracyanoethylene (TCNE). The redox behavior of novel azulene derivatives 12-17 was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed multistep electrochemical reduction properties. Moreover, a significant color change was observed by visible spectroscopy under electrochemical reduction conditions. 相似文献
112.
Dr. Kazuhisa Yamasumi Kentaro Ueda Dr. Yohei Haketa Dr. Yusuke Hattori Prof. Masayuki Suda Prof. Shu Seki Dr. Hayato Sakai Prof. Taku Hasobe Ryoya Ikemura Prof. Yoshitane Imai Dr. Yukihide Ishibashi Prof. Tsuyoshi Asahi Dr. Kazuto Nakamura Prof. Hiromitsu Maeda 《Angewandte Chemie (International ed. in English)》2023,62(8):e202216013
Squarylium-based π-electronic cation with an augmented dipole was synthesized by methylation of zwitterionic squarylium. The cation formed various ion pairs in combination with anions, and the ion pairs exhibited distinct photophysical properties in the dispersed state, ascribed to the formation of J- and H-aggregates. The ion pairs provided solid-state assemblies based on cation stacking. It is noteworthy that complete segregation of cations and anions was observed in a pseudo-polymorph of the ion pair with pentacyanocyclopentadienide as a π-electronic anion. In the crystalline state, the ion pairs exhibited photophysical properties and electric conductivity derived from cation stacking. In particular, the charge-segregated ion-pairing assembly induces an electric conductive pathway along the stacking axis. The charge-segregated mode and fascinating properties were derived from the reduced electrostatic repulsion between adjacent π-electronic cations via dipole–dipole interactions. 相似文献
113.
Eiji Fujimori Tatsuya Kobayashi Masanori Aoki Masahiro Sakaguchi Tsuyoshi Saito Taku Fukai Hiroki Haraguchi 《Analytical sciences》2007,23(12):1359-1366
PM10 samples were collected at an urban site of Nagoya City during September, 2003, to August, 2004, and annual variations of the concentrations of the elements in PM10 samples were examined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The annual concentration variations of ca. 30 elements in ambient air were in the range from sub-ng m(-3) to several microg m(-3). From an evaluation by the enrichment factors of the elements, elements such as Al, Ca, Fe, Mg, Ti, Mn, Ba, Sr, Ce, La, Nd, Co, Cs, and Pr, in PM10 samples were found to have originated mostly from natural sources, while the elements such as S, Zn, Pb, Cu, Ni, Sb, Sn, Cd, Bi, W, Tl, and In originated from anthropogenic emission sources. Furthermore, in seasonal variations of the elemental concentrations of PM10 samples in ambient air, the elements originated mostly from natural sources provided significantly high concentrations in spring during the "Kosa" period (the dust season from March to May). On the other hand, the elements mainly from anthropogenic emission sources provided relatively higher concentrations in autumn and winter, which may be explained by the fact that the urban atmospheric structure is stabilized by the temperature-inversion layer formed over the city in those seasons. In addition, all of the elements provided significantly low concentrations in the summer, due to the dilution effect of the oceanic winds as well as due to the convection of air mass up to the high levels. 相似文献
114.
Naoto Hayashi Taisetsu Ueno Naoki Okamoto Takahiro Mori Naho Sasaki Taku Kamoto Junro Yoshino Hiroyuki Higuchi Hidehiro Uekusa Hideyuki Tukada 《Tetrahedron letters》2017,58(26):2547-2550
Although molecular amorphous materials represent an important area of research in solid-state chemistry, studies pertaining to these systems have been restricted almost exclusively to amorphous solids based on a single molecule. In this study, we found that, while the 2,4,6-bis(4-tert-butylphenyl)phenoxyl radical (2M) and its dimer (2D) did not give single-component amorphous solids, they rapidly formed the corresponding binary amorphous solid IIa following their condensation from benzene, dichloromethane, chloroform, and ethyl acetate solutions. The formation of IIa could be attributed to the good solubilities of 2M and 2D in these solvents and the high packing efficiencies of these amorphous solids. IIa was also obtained when crystals of 2D (IIb) were ground together. The solid-state formation of IIa would not only involve the locational exchange of 2M and 2D, but would also involve chemical exchanges. 相似文献
115.
Yoshiya T Taniguchi A Sohma Y Fukao F Nakamura S Abe N Ito N Skwarczynski M Kimura T Hayashi Y Kiso Y 《Organic & biomolecular chemistry》2007,5(11):1720-1730
The O-acyl isopeptide method has recently received attention as an efficient synthetic method for peptides. Herein, forty kinds of "O-acyl isodipeptide unit" Boc-Ser/Thr(Fmoc-Xaa)-OH (1-40) were effectively synthesized in two-steps without epimerization. The O-acyl isodipeptide units are important building blocks to enable the routine use of the O-acyl isopeptide method. 相似文献
116.
Taku Aiga Dr. Yoshiyuki Manabe Keita Ito Tsung-Che Chang Dr. Kazuya Kabayama Shino Ohshima Prof. Yoshie Kametani Ayane Miura Hiroto Furukawa Dr. Hiroshi Inaba Prof. Kazunori Matsuura Prof. Koichi Fukase 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(40):17858-17864
Co-assembling vaccines composed of a lipidated HER2-derived antigenic CH401 peptide and either a lipophilic adjuvant, Pam3CSK4, α-GalCer, or lipid A 506, were evaluated as breast cancer vaccine candidates. This vaccine design was aimed to inherit both antigen multivalency and antigen-specific immunostimulation properties, observed in reported self-adjuvanting vaccine candidates, by using self-assembly and adjuvant-conjugated antigens. Under vaccination concentrations, respective lipophilic adjuvants underwent co-assembly with lipidated CH401, which boosted the anti-CH401 IgG and IgM production. In particular, α-GalCer was responsible for the most significant immune activation. Therefore, the newly developed vaccine design enabled the optimization of adjuvants against the antigenic CH401 peptide in a simple preparatory manner. Overall, the co-assembling vaccine design opens the door for efficient and practical self-adjuvanting vaccine development. 相似文献
117.
Satoh T Sumaru K Takagi T Takai K Kanamori T 《Physical chemistry chemical physics : PCCP》2011,13(16):7322-7329
Spirobenzopyrans, which are well known as photochromic compounds, exist as thermodynamically stable protonated ring-opened isomers (protonated merocyanine form, McH) in an acidic aqueous solution in the dark. In the present study, we investigated effects of substitution of the spirobenzopyrans on a ring-opening behavior in an aqueous system. We prepared five polymerizable spirobenzopyrans that are substituted with a methoxy group or a nitro group at the 6'- or 8'-positions and without a substituent. These monomers were copolymerized with N,N-dimethylacrylamide to evaluate the spirobenzopyrans in aqueous solution. Correlation between ring-opening rates and the kind and position of the substitution can be summarized as follows: the substitution of an electron-donating methoxy group and the substitution at the 8'-position increased the ring-opening rate, whereas the substitution of an electron-withdrawing nitro group decreased the rate. The effects of the substitution can be explained by changes in the electron density of the oxygen atom of the spirobenzopyrans. 相似文献
118.
Catalytic conversion of cellulose into 5-hydroxymethylfurfural in high yields via a two-step process
Xinhua Qi Masaru Watanabe Taku M. Aida Richard L. SmithJr. 《Cellulose (London, England)》2011,18(5):1327-1333
As a key renewable chemical for plastics and fine chemicals, the preparation of 5-hydroxymethylfurfural (5-HMF) from biomass
is an important research topic. Cellulose, although abundant in nature, is difficult to convert to 5-HMF in good yields due
to its recalcitrant and heterogeneous nature. In this work, we show an efficient two-step process for converting microcrystalline
cellulose into 5-HMF with ionic liquids under mild conditions. In the first step, high glucose yields of above 80% could be
obtained from the cellulose hydrolysis by a strong acidic cation exchange resin in 1-ethyl-3-methyl imidazolium chloride ([EMIM][Cl])
with gradual addition of water. In the second step, the resin was separated from the reaction mixture and CrCl3 was added which lead to a 5-HMF yield of 73% based on cellulose substrate. The strategy can allow practical conversion of
biomass into bio-derived products. 相似文献
119.
Okabayashi T Kurahara T Okabayashi EY Tanimoto M 《The Journal of chemical physics》2012,136(17):174311
Platinum monofluoride (PtF) and platinum monochloride (PtCl) were detected in the gas phase using a source-modulated microwave spectrometer. The PtF and PtCl radicals were generated in a free space cell using the sputtering reaction from a platinum sheet placed on the inner surface of a stainless steel cathode through a dc glow discharge plasma of CF(4) and Cl(2), respectively, diluted with Ar. Rotational transitions were measured in the region between 150 and 313 GHz. Rotational, centrifugal distortion, and several fine- and hyperfine-structure constants were determined by a least-squares analysis. The observed fine-structure spectral patterns indicate that both PtF and PtCl radicals have the (2)Π(3/2) electronic ground states, while the related cyanide PtCN and hydride PtH radicals have the (2)Δ(5/2) electronic ground states. 相似文献
120.