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991.
992.
Haruko Ikeuchi Mitsuhiro Kanakubo Shin Okuno Rika Sato Koichi Fujita Manatsu Hamada Nobuhiro Shoda Kenta Fukui Koji Okada Hikaru Kanazawa Akira Iimori Daisaku Miyake Takeshi Takeda Gen P. Satô 《Journal of solution chemistry》2010,39(10):1428-1453
The densities and the viscosities of tris(acetylacetonato)cobalt(III) solutions in acetonitrile, dichloromethane, chloroform, tetrachloromethane, benzene, toluene, ethylbenzene, and p-xylene were measured in the dilute concentration regions at several temperatures ranging from 278 to 313 K under ambient pressure. The partial molar volumes of the solvents and solute were calculated. They are independent of concentration and increase slightly as the temperature increases. The viscosity A- and B-coefficients of the Jones-Dole equation were obtained. The A-coefficients were found to be zero within experimental error. The B-coefficients are positive and decrease as the temperature increases. Thermodynamic quantities of activation for viscous flow were calculated on the basis of Eyring’s viscosity equation. From the quantities obtained in this study, along with some information from the literature, it is suggested that structure-making interactions occur between the segments of the complex and the solvent molecules. These interactions include electrostatic interactions between the local charge on the complex and the dipole moment of the solvent in solutions of acetonitrile and dichloromethane, interlocking packing interactions along C 3-axis of the complex with solvent in solutions of chloroform and tetrachloromethane, and π-electron interactions between the chelate ring of the complex and the solvent in solutions of benzene, toluene, ethylbenzene, and p-xylene. 相似文献
993.
Kenji Watanabe Shigeru Negi Dr. Yukio Sugiura Prof. Dr. Akiko Kiriyama Dr. Akino Honbo Katsumi Iga Prof. Dr. Eiichi N. Kodama Dr. Takeshi Naitoh Masao Matsuoka Prof. Dr. Koji Kano Prof. Dr. 《化学:亚洲杂志》2010,5(4):825-834
Interactions of multivalent anionic porphyrins and their iron(III) complexes with cationic peptides, V3Ba‐L and V3IIIB, which correspond to those of the V3 loop regions of the gp120 envelope proteins of the HIV‐1Ba‐L and HIV‐1IIIB strains, respectively, are studied by UV/Vis, circular dichroism, 1H NMR, and EPR spectroscopy, a microcalorimetric titration method, and anti‐HIV assays. Tetrakis(3,5‐dicarboxylatophenyl)porphyrin (P1), tetrakis[4‐(3,5‐dicarboxylatophenylmethoxy)phenyl]porphyrin (P2), and their ferric complexes (FeIIIP1 and FeIIIP2) were used as the multivalent anionic porphyrins. P1 and FeIIIP1 formed stable complexes with both V3 peptides (binding constant K>106 M ?1) through combined electrostatic and van der Waals interactions. Coordination of the His residues in V3Ba‐L to the iron center of FeIIIP1 also played an important role in the complex stabilization. As P2 and FeIIIP2 form self‐aggregates in aqueous solution even at low concentrations, detailed analysis of their interactions with the V3 peptides could not be performed. To ascertain whether the results obtained in the model system are applicable to a real biological system, anti‐HIV‐1BA‐L and HIV‐1IIIB activity of the porphyrins is examined by multiple nuclear activation of a galactosidase indicator (MAGI) and 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assays. There is little correlation between chemical analysis and actual anti‐HIV activity, and the size rather than the number of the anionic groups of the porphyrin is important for anti‐HIV activity. All the porphyrins show high selectivity, low cytotoxicity, and high viral activity. FeIIIP1 and FeIIIP2 are used for the pharmacokinetic study. Half‐lives of these iron porphyrins in serum of male Wistar rats are around 4 to 6 h owing to strong interaction of these porphyrins with serum albumin. 相似文献
994.
Yamada M Minowa M Sato S Kako M Slanina Z Mizorogi N Tsuchiya T Maeda Y Nagase S Akasaka T 《Journal of the American Chemical Society》2010,132(50):17953-17960
Thermal carbosilylation of endohedral dimetallofullerene La(2)@I(h)-C(80) with silirane (silacyclopropane) is reported herein for the first time. Two diastereomers of the carbosilylated La(2)@I(h)-C(80) have been isolated and characterized. The fascinating molecular structure of one diastereomer of the carbosilylated derivatives has been determined unambiguously using X-ray crystallographic analysis. Detailed characteristics of the molecular structures including their metal atom movements have also been revealed using NMR spectroscopic studies and computational calculations. Results revealed that two La atoms move dynamically inside the carbon sphere. Furthermore, electrochemical study has demonstrated that carbosilylation is effective to fine-tune the La(2)@I(h)-C(80) electronic properties. 相似文献
995.
Hisayuki Horai Masanori Arita Shigehiko Kanaya Yoshito Nihei Tasuku Ikeda Kazuhiro Suwa Yuya Ojima Kenichi Tanaka Satoshi Tanaka Ken Aoshima Yoshiya Oda Yuji Kakazu Miyako Kusano Takayuki Tohge Fumio Matsuda Yuji Sawada Masami Yokota Hirai Hiroki Nakanishi Kazutaka Ikeda Naoshige Akimoto Takashi Maoka Hiroki Takahashi Takeshi Ara Nozomu Sakurai Hideyuki Suzuki Daisuke Shibata Steffen Neumann Takashi Iida Ken Tanaka Kimito Funatsu Fumito Matsuura Tomoyoshi Soga Ryo Taguchi Kazuki Saito Takaaki Nishioka 《Journal of mass spectrometry : JMS》2010,45(7):703-714
MassBank is the first public repository of mass spectra of small chemical compounds for life sciences (<3000 Da). The database contains 605 electron‐ionization mass spectrometry(EI‐MS), 137 fast atom bombardment MS and 9276 electrospray ionization (ESI)‐MSn data of 2337 authentic compounds of metabolites, 11 545 EI‐MS and 834 other‐MS data of 10 286 volatile natural and synthetic compounds, and 3045 ESI‐MS2 data of 679 synthetic drugs contributed by 16 research groups (January 2010). ESI‐MS2 data were analyzed under nonstandardized, independent experimental conditions. MassBank is a distributed database. Each research group provides data from its own MassBank data servers distributed on the Internet. MassBank users can access either all of the MassBank data or a subset of the data by specifying one or more experimental conditions. In a spectral search to retrieve mass spectra similar to a query mass spectrum, the similarity score is calculated by a weighted cosine correlation in which weighting exponents on peak intensity and the mass‐to‐charge ratio are optimized to the ESI‐MS2 data. MassBank also provides a merged spectrum for each compound prepared by merging the analyzed ESI‐MS2 data on an identical compound under different collision‐induced dissociation conditions. Data merging has significantly improved the precision of the identification of a chemical compound by 21–23% at a similarity score of 0.6. Thus, MassBank is useful for the identification of chemical compounds and the publication of experimental data. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
996.
997.
Silica glass can be machined by irradiation with laser plasma soft X-rays on nano- and micrometer scale. We have investigated the ablation process of silica glass induced by laser plasma soft X-ray irradiation. We observed ionic and neutral species emitted from silica surfaces after irradiation. Dominant ions and neutrals are O+ and Si+ ions and Si, O, SiO and Si2 neutrals, respectively. The ions have kinetic energies of 13 and 25 eV, which are much higher than those of particles emitted by evaporation. The energy of laser plasma soft X-rays absorbed to silica glass at a fluence of 1.4 J/cm2 is estimated to be 380 kJ/cm3, which is higher than the binding energy of SiO2 of 76 kJ/cm3. These results suggest that the most of the bonds in silica glass are broken by absorption of laser plasma soft X-rays, that several percent of the atoms are ionized, and that neutral atoms are emitted together with repulsive ions. The process possibly enables us to fabricate nano structures. 相似文献
998.
Manabu Hamada Yoshikazu Inami Yasuhito Nagai Toshinori Higashi Mitsuru Shoji Seiichiro Ogawa Kazuo Umezawa Takeshi Sugai 《Tetrahedron: Asymmetry》2009,20(18):2105-2111
3,8-Dioxatricyclo[3.2.1.02,4]octane-6-carboxylic acid, whose racemic form is readily available on a large scale, is a versatile starting material for the synthesis of carbasugars and carbocyclic biologically active natural products. In this study, the enzyme-catalyzed kinetic resolution was attempted on a variety of corresponding carboxylic esters. The hydrophobic and hydrophilic properties of ester substituents greatly affected the rate of reaction and the enantioselectivity. Hydrolysis of the corresponding 2′-chloroethyl ester with pig liver esterase worked well in a highly enantioselective manner (E = 116) to give the hydrolyzate (90.6% ee) and unreacted ester recovery (99.4% ee). The hydrolyzate is a precursor for (−)-oseltamivir phosphate, and a route to (3S,4S,5R)-(−)-3-epishikimic acid was developed from the recovered ester. 相似文献
999.
A barium vanadium bronze Ba1+xV8O21 has been hydrothermally synthesized and structurally characterized. Hydrothermal treatment of a suspension of VO2 powders in Ba(NO3)2 solution at 350°C yielded a fibrous brown compound having nonstoichiometric composition Ba1+xV8O21 (x=0.13). Single-crystal X-ray diffractometry revealed the monoclinic system C2/m with a=15.144(6), b=3.596(4), c=14.972(3) Å, β=90.08(3)°, and Z=2, with the refinement based on 2021 reflections with I>3σ(I) converged to R=0.054 and Rw=0.046. A new tunnel-type bronze structure was disclosed in which VO6 octahedra and VO5 trigonal bipyramids form a V–O framework with a tunnel cavity running along [010]. The Ba atom partially occupies the tunnel site with more than half occupancy of 56.6%, which causes displacement of the Ba atom and further displacement of V and O atoms along the tunnel axis. Ba1+xV8O21 is the first tunnel-type barium vanadium bronze whose structure has been fully determined. 相似文献