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1.
Yoshio Moriya Shinichi Nakata Hirotaka Morimoto Nobuaki Ogawa 《Analytical sciences》2004,20(11):1533-1536
Analysis by reflection spectrometry was performed to clarify the interfacial adsorption of protonated lipophilic tetraphenylporphyrin derivatives in a dodecane-aqueous sulfuric acid system, and to confirm the utility of partial reflection spectroscopy. Interfacial adsorption was not observed for porphyrins substituted at the 2,6 positions of meso-phenyl groups, suggesting that the substituents prevent porphyrins from forming aggregates by steric hindrance. Polymorphous J-aggregates of acid dications were produced by tetra-p-tolylporphyrin with a saturated interfacial molecular density of 1.0 x 10(-10) mol cm(-2), which could yield 48 degrees as a mean tilting angle of the pyrrole ring plane from the interface normal. Partial-reflection spectrometry can provide sensitive detection and molecular orientation analysis of interfacial adsorbates. 相似文献
2.
Kiyoshi Mochizuki 《Journal of Mathematical Analysis and Applications》2007,326(1):582-588
We show that the energy of solutions to the initial boundary value problem for the wave equation in exterior domains with a dissipation which is localized only near infinity tends to zero as the time goes to infinity. We do not make any geometrical condition like star-shapedness on the boundary. 相似文献
3.
Changes in the fluorescence intensity of polyanions bearing 4-acryloylbenzo-18-crown-6 units on the addition of cations were studied in a mixed solvent of methanol and water at 30°C. The sensitivity of the change in fluorescence intensities of the polymers toward cations was strongly enhanced compared to that of the corresponding model compound. When alkali metal cations were added, the fluorescence intensity of the polymers decreased in the orders Li+>Na+>Cs+>Rb+>K+ in a methanol-water (19) mixture and Li+>Na+>Rb+>K+Cs+ in a methanol-water (91) mixture. Alkaline earth metal cations and alkylamine hydrochlorides decreased the fluorescence intensity of the polymers in a methanol-water (19) mixture. The cation-dependent decrease in the fluorescence intensity of the polymers was affected by the water fraction in a mixed solvent of methanol and water. 相似文献
4.
A novel enantiopure 1,2-diamine (5) having two phenolic hydroxy groups was attached into chloromethylated polystyrene through benzyl ether linkage, which was used as a chiral ligand of the catalyst in asymmetric hydrogenation of acetophenone. 相似文献
5.
Enami S Yamanaka T Hashimoto S Kawasaki M Tonokura K 《The journal of physical chemistry. A》2005,109(27):6066-6070
The reactions of Cl atoms with RI (R = n-C3H7, n-C4H9, cyclo-C6H11, C6H5, C6F5, and p-CH3C6H4) have been studied using cavity ring-down spectroscopy at a temperature range of 233-313 K and at 100 Torr total pressure of N2 diluent. Visible absorption spectra of the RI-Cl adducts were recorded at 440-520 nm at 263 K. The yields of the adducts were temperature-dependent. There was no discernible reaction of the adducts in the presence of 100 Torr of O2 at 263 K. Theoretical calculations were performed for C4H9I-Cl and C6H5I-Cl for quantitative explanation of the absorption spectra and the strength of the I-Cl bonds in the charge-transfer complexes. Evidence for the adduct formation following the reaction of Cl with C6H5Br was sought but not found at 440 and 520 nm. 相似文献
6.
Fukuji Higashi Michihide Ozawa Akihiko Mochizuki 《Journal of polymer science. Part A, Polymer chemistry》1986,24(4):637-643
The reaction promoted by diphenyl chlorophosphate (DPCP) in pyridine was successfully applied to the preparation of soluble aromatic copolyesteramides of high molecular weights directly from aromatic dicarboxylic acids, bisphenols, and a wide range of mol % aromatic diamines. Dropwise addition of a mixture of bisphenols and diamines (more favorably of bisphenols and then diamines) to the mixture of dicarboxylic acids activated by DPCP led the reactions homogeneously even with high mol % of diamines to produce copolymers of good solubility. This improved copolymer solubility was roughly estimated by sequence distribution of polyamide and polyester units in the copolymers, which was studied in a model reaction and in the copolycondensations by simultaneous and stepwise addition of bisphenols and diamines. 相似文献
7.
Sun-Chan Jeong Ichiro Katayama Hirokane Kawakami Yutaka Watanabe Hironobu Ishiyama Nobuaki Imai Yoshikazu Hirayama Hiroari Miyatake Masao Sataka Hiroyuki Sugai Satoru Okayasu Shin-Ichi Ichikawa Katsuhisa Nishio Shinichi Mitsuoka Takamitsu Nakanoya Takashi Hashimoto Takanori Hashimoto Masahito Yahagi 《Solid State Ionics》2009,180(6-8):626-630
The diffusion coefficients of Li in the NaTl-type Li intermetallic compound of β-LiGa have been measured by using a short-lived radioactive diffusion tracer. As the tracer, the α-emitting radioisotope of 8Li delivered as the energetic and pulsed beam from Tokai Radioactive Ion Accelerator Complex (TRIAC) was implanted into the β-LiGa compounds with the composition in the range of about 43 to 54 at.% Li. By analyzing the time-dependent yields of the α-particles measured according to the repetition cycle of the beam, the tracer diffusion coefficients were extracted over the wide range of Li composition. Abnormal composition-dependence of Li diffusion coefficients in β-LiGa was observed; the stoichiometric β-LiGa showed the highest diffusivity of Li. By referring to the composition-dependent diffusivity of Li in the iso-structural β-LiAl and β-LiIn, we could identify the abnormal diffusion of Li in very Li-poor composition of β-LiGa. The anomaly has been discussed qualitatively in terms of the formation of defect complex and the interaction between the constitutional defects. 相似文献
8.
Takashi Hirate Takashi Kimpara Shinichi Nakamura Tomomasa Satoh 《Superlattices and Microstructures》2007,42(1-6):409
We made a study of controlling diameters of well-aligned ZnO nanorods grown by low-pressure thermal chemical vapor deposition combined with laser ablation of a sintered ZnO target, which was developed by us. Until now, it has been impossible to control diameters of ZnO nanorods, while the growth orientation was maintained well-aligned. In this study we developed a multi-step growth method to fabricate well-aligned nanorods whose diameters could be controlled. Metal Zn vapor and O2 are used as precursors to grow ZnO nanorods. N2 is used as a carrier gas for the precursors. A substrate is an n-Si (111) wafer. A sintered ZnO target is placed near the substrate and ablated by a Nd–YAG pulsed laser during ZnO nanorod growth. The growth temperature is 530 C and the pressure is 66.5 Pa. A vertical growth orientation of ZnO nanorods to the substrate is realized in the first-step growth although the diameter cannot be controlled in this step. When an O2 flow rate is 1.5 sccm, well-aligned nanorods with 100 nm diameter are grown. Next, the second-step nanorods are grown on only the flat tip of the first-step nanorods. The diameters of the second-step nanorods can be controlled by adjusting the O2 flow rate, and the growth direction is kept the same as that of the first-step nanorods. When the O2 flow rate in second-step growth is smaller than 0.6 sccm, the diameter of the second-step nanorods is 30–50 nm. When the O2 flow rate is between 0.75 and 3.0 sccm, the diameter is almost same as that of the first-step nanorods. When the O2 flow rate is larger than 4.5 sccm, the diameter is increased with increasing O2 flow rate. Further, the third-step ZnO nanorods with gradually increased diameters can be grown on the second-step nanorods with 1.5 sccm O2 flow rate and without laser ablation. 相似文献
9.
Hidemasa Azuma Yuzuru Katagiri Shinichi Yamabe 《Journal of polymer science. Part A, Polymer chemistry》1996,34(8):1407-1414
Transition states (TSs) of radical addition homopolymerization reactions of methyl acrylate, methyl methacrylate, dimethyl itaconate, and N-methyl itaconimide were examined with two-unit radical models using MOPAC (PM3 UHF) semiempirical method. Calculated activation energies (Eas) show good correlations with experimental values. Calculated activation entropies (−ΔS‡s) are found to be well proportional to Eas. The entropy terms play an important role as well as Ea in radical additions. Ea depends on the angle (θrs) between reaction points of radical and of monomer at TS. The bond length between reaction points at TS is constant regardless of monomers studied. The geometries and thermodynamical properties calculated here for TS indicate the importance of steric effects caused by substituted group(s) rather than electronic perturbation energies reported previously. © 1996 John Wiley & Sons, Inc. 相似文献
10.