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排序方式: 共有233条查询结果,搜索用时 46 毫秒
1.
Takumi Watanabe Yuichiro Nishizawa Haruka Minato Dr. Chihong Song Prof. Dr. Kazuyoshi Murata Prof. Dr. Daisuke Suzuki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):8934-8938
The three-dimensional structure of nanocomposite microgels was precisely determined by cryo-electron micrography. Several nanocomposite microgels that differ with respect to their nanocomposite structure, which were obtained from seeded emulsion polymerization in the presence of microgels, were used as model nanocomposite materials for cryo-electron micrography. The obtained three-dimensional segmentation images of these nanocomposite microgels provide important insights into the interactions between the hydrophobic monomers and the microgels, that is, hydrophobic styrene monomers recognize molecular-scale differences in polarity within the microgels during the emulsion polymerization. This result led to the formation of unprecedented multi-layered nanocomposite microgels, which promise substantial potential in colloidal applications. 相似文献
2.
N Motohashi Y Nakamichi I Mori H Nishikawa J Umemoto 《Chemical & pharmaceutical bulletin》1990,38(7):1953-1956
The concentration and degradation of hyaluronic acid in the synovial fluid of carrageenin-induced arthritic joints of rabbits was studied. A 0.5-ml volume of 1% lambda-carrageenin was intra-articularly injected three times into a right knee joint, and saline into a left. After 5 d from the last injection, inflammatory changes were observed in the synovial membrane and synovial fluid, but not in the articular cartilage. In the inflammatory synovial fluid, lipid peroxide content, phosphatase activity and cell counts were significantly increased, but the copper concentration was not changed. Concentration of polymeric hyaluronic acid and total hyaluronic acid were determined by high-performance liquid chromatography using gel-permeation columns. Total hyaluronic acid was appreciably decreased in the inflammatory fluid. The polymeric hyaluronic acid determined was 38% of the total hyaluronic acid in the inflammatory fluid and 74% in the control fluid. This suggests that in the inflammatory fluid, molecular weights of hyaluronic acid are distributed in the broader range. The concentration of chondroitin sulphates was similar in both the inflammatory fluid and the control fluid, but the content ratio of chondroitin sulphates to hyaluronic acid was higher in the inflammatory fluid. In the inflamed synovial membrane, synthesis of hyaluronic acid as measured by incorporation of [14C]glucosamine into glycoconjugates was increased by about twice that in the control membrane. 相似文献
3.
Seto Y. Umemoto K. Arii T. Masuda Y. 《Journal of Thermal Analysis and Calorimetry》2004,76(1):165-177
New solid complex of nitrilotriacetic acid and bismuth trichloride was synthesized by a solid phase reaction of nitrilotriacetic
acid and bismuth trichloride at room temperature. The composition of the sample is BiCl3[N(CH2COOH)3]2.5. The crystal structure of the complex belongs to triclinic system with the lattice parameters: α=0.7849 nm, β=0.9821 nm,
χ=2.0021 nm, α=96.50°, β=98.76° and γ=90.49°. The far-infrared spectra show the bonding between the Bi ion and N atom of nitrilotriacetic
acid. The thermal analysis also demonstrates the complex formation between the bismuth ion and nitrilotriacetic acid. The
gaseous pyrolysis product and the final residue in the thermal decomposition process are determined to check the thermal decomposition
reaction.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Yoshizawa M Nagao M Umemoto K Biradha K Fujita M Sakamoto S Yamaguchi K 《Chemical communications (Cambridge, England)》2003,(15):1808-1809
Despite their structural similarity, triangular tetradentate ligands 2b and 2c experience different assembly pathways on complexation with (en)Pd(NO3)2 to give M8L4 tetrahedral (3) and open cone (4) structures, respectively, due to steric restriction by side chains at the corner or on the edge of the ligands. 相似文献
5.
Perfluoroalkylation of alkynes with RfI(Ph)OSO2CF3 is described. This offers the first example of electrophilic perfluoroalkylation of alkynes. 相似文献
6.
7.
Dr. Tsubasa Nakashima Haruka Fujimori Dr. Kohsuke Ohmatsu Prof. Takashi Ooi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(36):9253-9256
Intermediary radical cations, generated through single-electron oxidation of enol silyl ethers by excited Ir-based photocatalysts, can be exploited as Brønsted acids for the activation of heteroarylcyanides. This strategy enables the direct allylic C−H heteroarylation of enol silyl ethers under visible-light irradiation. 相似文献
8.
Prof. Dr. Tomoaki Tanase Dr. Kanako Nakamae Haruka Miyano Prof. Dr. Yasuyuki Ura Prof. Dr. Yasutaka Kitagawa Dr. Shiho Yada Prof. Dr. Tomokazu Yoshimura Prof. Dr. Takayuki Nakajima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(47):12078-12103
A series of the octapalladium chains supported by meso-Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 (meso-dpmppm) ligands, [Pd8(meso-dpmppm)4(L)2](BF4)4 (L=none ( 1 ), solvents: CH3CN ( 2 a ), dmf ( 2 b ), dmso ( 2 c ), RN≡C: R=Xyl ( 3 a ), Mes ( 3 b ), Dip ( 3 c ), tBu ( 3 d ), Cy ( 3 e ), CH3(CH2)7 ( 3 f ), CH3(CH2)11 ( 3 g ), CH3(CH2)17 ( 3 h )) and [Pd8(meso-dpmppm)4(X)2](BF4)2 (X=Cl ( 4 a ), N3 ( 4 b ), CN ( 4 c ), SCN ( 4 d )), were synthesized by using 2 a as a stable good precursor, and characterized by spectroscopic (IR, 1H and 31P NMR, UV-vis-NIR, ESI-MS) measurements and X-ray crystallographic analyses (for 1 , 2 a , b , 3 a , b , e , f , 4 a – d ). On the basis of DFT calculations on the X-ray determined structure of 2 b ( [2b-Pd8]4+ ) and the optimized models [Pd8(meso-Ph2PCH2P(H)CH2P(H)CH2PH2)4(CH3CN)2]4+ ( [Pd8Ph8]4+ ) and [Pd8(meso-H2PCH2P(H)CH2P(H)CH2PH2)4(CH3CN)2]4+ ( [Pd8H8]4+ ), with and without empirically calculating dispersion force stabilization energy (B3LYP-D3, B3LYP), the formation energy between the two Pd4 fragments is assumed to involve mainly noncovalent interactions (ca. −70 kcal/mol) with four sets of interligand C−H/π interactions and Pd⋅⋅⋅Pd metallophilic one, while electron shared covalent interactions are almost canceled out within the Pd8 chain. All the compounds isolated are stable in solution and exhibit characteristic absorption at ∼900 nm, which is assignable to a spin allowed HOMO to LUMO transition, and shows temperature dependent intensity change with variable absorption coefficients presumably due to coupling with some thermal vibrations. The structures and electronic states of the Pd8 chains are found finely tunable by varying the terminal capping ligands. In particular, theoretical calculations elucidated that the HOMO-LUMO energy gap is systematically related to the central Pd−Pd distance (2.7319(6)–2.7575(6) Å) by two ways with neutral ligands L ( 1 , 2 , 3 ) and with anionic ligands X ( 4 ), which are reflected on the NIR absorption energy of 867–954 nm. The isocyanide terminated Pd8 complexes ( 3 ) further reacted with excess of RNC (6 eq) to afford the Pd4 complexes, [Pd4(meso-dpmppm)2(RNC)2](BF4)2 ( 13 ), and the cyclic voltammograms of 2 a (L=CH3CN), 3 , and 13 (R=Xyl, Mes, tBu, Cy) demonstrated wide range redox behaviors from 2{Pd4}4+ to 2{Pd4}0 through 2{Pd4}2+↔{Pd8}4+, {Pd8}3+, and {Pd8}2+ strings. The oxidized complexes, [Pd4(meso-dpmppm)2(RNC)3](BF4)4 ( 16 ), were characterized by X-ray analyses, and the two-electron reduced chain of [Pd8(meso-dpmppm)4](BF4)2 ( 7 ) was analyzed by spectroscopic and electrochemical techniques and DFT calculations. Reactions of 2 a with 1 equiv. of aromatic linear bisisocyanide (BI) in CH2Cl2 deposited insoluble coordination polymers, {[Pd8(meso-dpmppm)4(BI)](BF4)4}n ( 5 ), and interestingly, they were soluble in acetonitrile, 31P{1H} and 1H DOSY NMR spectra as well as SAXS curves suggesting that the coordination polymers may exist in acetonitrile as dynamically 1D self-assembled coordination polymers comprising ca. 50 units of the Pd8 rod averaged within the timescale. 相似文献
9.
Bungo Ochiai Haruka Kojima Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2014,52(8):1113-1118
Polyhydroxyurethane bearing silicone backbone was prepared by polyaddition of silicone diamines with a bifunctional five‐membered cyclic carbonate prepared from the corresponding diepoxide and CO2. Polymerization in propylene glycol methyl ether acetate proceeded smoothly, and polymers could be obtained in high yields under appropriate conditions. The introduced silicone moieties improved the hydrophobicity and lowered the glass transition temperature keeping thermal stability. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1113–1118 相似文献
10.
Kaisei Matsumoto Kazuki Ueno Prof. Dr. Jun Hirotani Prof. Dr. Yutaka Ohno Prof. Dr. Haruka Omachi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6118-6121
Owing to their remarkable properties, single-walled carbon nanotube thin-film transistors (SWCNT-TFTs) are expected to be used in various flexible electronics applications. To fabricate SWCNT channel layers for TFTs, solution-based film formation on a self-assembled monolayer (SAM) covered with amino groups is commonly used. However, this method uses highly oxidized surfaces, which is not suitable for flexible polymeric substrates. In this work, a solution-based SWCNT film fabrication using methoxycarbonyl polyallylamine (Moc-PAA) is reported. The NH2-terminated surface of the cross-linked Moc-PAA layer enables the formation of highly dense and uniform SWCNT networks on both rigid and flexible substrates. TFTs that use the fabricated SWCNT thin film exhibited excellent performance with small variations. The presented simple method to access SWCNT thin film accelerates the realization of flexible nanoelectronics. 相似文献