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111.
Kiitiro Utimoto Michio Obayashi Yuho Shishiyama Masaharu Inoue Hitosi Nozaki 《Tetrahedron letters》1980,21(35):3389-3392
Triethylaluminium-mediated reaction of cyanotrimethylsilane with 6-methylbicyclo[4.4.0]dec-1-en-3-one affords a mixture of diastereomeric 1,4-adducts. The reaction is kinetically controlled in toluene, whereas thermodynamically in refluxing THF. 4-Methyl-3-penten-2-one and carvone analogously give the respective 1,4-adducts and a conjugated dienone addords the 1,6-adduct in good yield. 相似文献
112.
The absolute configuration of phomopsidin, a marine-derived fungal metabolite from Phomopsis sp. isolated at Pohnpei, was determined by the exciton chirality method as 6S, 7S, 8S, 11S, 12R, and 15R. The biosynthetic study using 13C-labeled precursors revealed the origin of all carbon atoms in phomopsidin, which was built by nine acetates and three methyl groups from l-methionine. Inhibitory activities of phomopsidin and its Me ester derivative against microtubule assembly were examined together with the structurally related compounds MK8383, solanapyrones, and tanzawaic acids. Phomopsidin and its (16Z)-isomer (MK8383) showed anti-microtubule activity at IC50 of 5.7 and 8.0 μM, respectively, while the Me ester and other compounds were not active at 100 μM. 相似文献
113.
Mr = 295.84, triclinic, Pl, a = 6.786(1), b = 7.658(1), c = 8.561(1) Å, α = 108.17(1), β = 97.94(1), γ = 103.32(2)°, V = 400.6 Å3, Z = 1,Dm = 1.23, Dx = 1.226 Mgm?3, δ(Cu Kα) = 1.5418 Å, μ = 20.81 cm?1, F(000) = 160. The structure has been solved by direct and Fourier methods and refined by a least-squares procedure to the final R = 0.043 for 1182 observed reflections (|Fo] >3σ(Fo)). cis-1-Phenyl-3-piperidinocyclohexan-1-ol possessing 1,3-diaxial positions between the piperidine and hydroxyl groups is converted to the isomer with 1,3-diequatorial positions in its hydrochloride. The hydrogen bond is formed between the chloride anion and the protonated nitrogen atom of piperidine instead of the intramolecular hydrogen bond in the free cis-base between the oxygen and nitrogen atoms. 相似文献
114.
Michio Kunieda 《Tetrahedron》2004,60(50):11349-11357
We prepared bacteriochlorophyll(BChl)-b and g models by Diels-Alder reactions of 8-vinyl-chlorophylls with tetracyanoethylene. The resulting 8-alkylidene-bacteriochlorins with various substituent groups at the 3-position had the same π-conjugate as BChls-b/g. While the natural pigments isomerized by addition of an acid to afford the corresponding chlorins, the synthetic models were stable under the acidic conditions due to dialkylation at the 7-position. These BChl-b/g models are useful for investigating the optical properties of relatively unstable BChls-b/g. 相似文献
115.
The method is based on the redox reaction between 4,4′-tetramethyldiaminothiobenzophenone (thio-Michler's ketone) and chlorine at pH 3.5; 2-methoxyethanol and Triton X-100 are used to keep the reagent in solution. The absorbance of the blue quinoidal product is measured at 640 nm. Linear calibration is obtained for 0.2?1.0 mg l?1 chlorine. The method is suitable for tap waters. 相似文献
116.
Abstract The effect of continuous far-red (FR) preirradiation on the accumulation of chlorophyll (Chi) during a white light (WL; 500 lx) period was examined using Pharbitis nil cotyledons. The saturation level of accumulated Chi attained after prolonged exposure to WL was always lowered by continuous FR irradiation preceding the WL. The rate of Chi accumulation during the rapid increase phase (operationally defined as the amount of Chi accumulated during a 24-h WL period) was enhanced by preirradiation with up to 36 h of FR. However, when the FR preirradiation lasted longer, the rate was reduced below the dark control level. Even FR preirradiation of up to 36 h fully reduced the rate of Chi accumulation under WL when 36 h or longer darkness was spaced between the FR and the WL period. 相似文献
117.
A novel electrolytic transformation of olefins into oxyselenides has been performed in high yields and high regioselectivities by elctrolyzing olefins in protic solvents (MeOH, AcOH, H2O-MeCN) containing Et4NX (X = Cl, Br, I) and diphenyl diselenide using platinum foils. 相似文献
118.
Kazuhiro Tsuji Michio Sorai Hiroshi Suga Syüzö Seki 《Molecular Crystals and Liquid Crystals》2013,570(3-4):305-317
Abstract The heat capacity of HBAF has been measured between 15 K and 385 K. Four phase transitions were found at 328.07 K (crystal-smectic B); 330.33 K (smectic B-smectic A); 334.88 K (smectic A-nematic); and 336.33 K (nematic-isotropic liquid), respectively. The enthalpies and entropies of these transitions were determined to be 23.22 kJ mol?1/70.7 JK?1 mol?1; 3.05/9.2; 3.41/10.2; and 1.17/3.5, respectively. The total transition entropy of HBAF agreed well with those previously reported for the present homologues. The standard thermodynamic functions were estimated up to 385 K. The heat capacity curve of HBAF in the transition region had a close resemblance to that of p-n-hexyloxybenzylideneamino-p'-chlorobenzene. The entropies of the smectic A-nematic and nematicisotropic liquid transitions were compared with those theoretically derived by McMillan. The smectic B-smectic A transition entropy was interpreted in terms of order-disorder phase transition associated with the orientation of molecule. 相似文献
119.
Michio Kobayashi Kentaro Okuma Hiroyuki Takeuchi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2)
Abstract Hitherto, the preparative method of the sulfoxonium ions has been practically limited to thealkylation of the sulfoxides with methyliodide. The yields of the desired sulfoxonium salts by this method are usually poor except that of trimethylsulfoxonium iodide, Diarylalkyl- or triaryl-sulfoxonium ions can not be prepared by this alkylation. 相似文献
120.