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991.
Harpagoside,which is one main iridoid constituent of the dried roots of Scrophularia ningpoensis Hemsl.,was biotransformated by bacteria isolated from human fecal flora and three metabolites were obtained.The structures of the metabolites,including two new alkaloids,named harpagometabolins I(1)and II(2),and a known alkaloid acubinine B(3),were identified by chemi cal methods and the spectroscopic evidences. 相似文献
992.
Nobuhiro Iwasa Masao Terashita Masahiko Arai Nobutsune Takezawa 《Reaction Kinetics and Catalysis Letters》2001,74(1):93-98
The catalytic performance of supported Pd and Pt catalysts for the title reaction was greatly improved upon the formation
of Pd and Pt alloys. Over Pd and Pt alloys, methyl formate was selectively hydrogenolyzed to methanol, while over metallic
Pd and Pt, it was decarbonylated to methanol and carbon monoxide.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
993.
Shin‐Ichi Hirota Yoichi Tominaga Shigeo Asai Masao Sumita 《Journal of Polymer Science.Polymer Physics》2005,43(21):2951-2962
An in situ dielectric measurement for atactic poly(methyl methacrylate) (at‐PMMA) was performed under high‐pressure CO2 under various pressures and temperatures. The at‐PMMA has the acetate side group with a large dipole moment. In the glassy state, a local relaxation process (β‐process) can be observed using dielectric measurement. In the rubbery state, the micro‐Brownian motion of main chain (α‐process) occurs, and the β‐process changes into αβ‐process coordinated with the α‐process. The dielectric loss (ε″) spectrum of at‐PMMA in the glassy state is asymmetric because of the density fluctuation for the amorphous structure. The loss peak frequency shifted to higher frequencies, and the relaxation strength increased with increasing CO2 pressure. In the glassy state, the shape of ε″ spectrum became more symmetric with increasing CO2 pressure. These show that the molecular mobility enhanced by the plasticization effect of CO2 allows the dipolar side groups in the high‐density region to contribute to the relaxation process. We also found that the apparent activation energy decreased under high‐pressure CO2. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2951–2962, 2005 相似文献
994.
Hatsuo Yamamura Hironori Tashiro Jumpei Kawasaki Koji Kawamura Kawai Masao 《Tetrahedron》2007,63(9):2064-2069
Five regioisomeric cyclomaltoheptaose (β-cyclodextrin) tetramesitylenesulfonates were prepared and each of them was isolated by a combination of reversed and ordinary phase chromatographic separations. The positions of the substituents on each regioisomer were unambiguously determined using interresidual NOEs. As a result of this study, an indexed library of sulfonylated β-cyclodextrins composed of 19 sulfonates has been established. 相似文献
995.
To deal with the robust portfolio selection problem where only partial information on the exit time distribution and on the conditional distribution of portfolio return is available, we extend the worst-case VaR approach and formulate the corresponding problems as semi-definite programs. Moreover, we present some numerical results with real market data. 相似文献
996.
Kentarou Imamura Masao Takahashi Shigeki Imai Hikaru Kobayashi 《Surface science》2009,603(7):968-5756
A relatively thick (i.e., ∼9 nm) SiO2 layer can be formed by oxidation of Si with nitric acid (HNO3) vapor below 500 °C. In spite of the low temperature formation, the leakage current density flowing through the SiO2 layer is considerably low, and it follows the Fowler-Nordheim mechanism. From the Fowler-Nordheim plots, the conduction band offset energy at the SiO2/Si interface is determined to be 2.57 and 2.21 eV for HNO3 vapor oxidation at 500 and 350 °C, respectively. From X-ray photoelectron spectroscopy measurements, the valence band offset energy is estimated to be 4.80 and 4.48 eV, respectively, for 500 and 350 °C oxidation. The band-gap energy of the SiO2 layer formed at 500 °C (8.39 eV) is 0.68 eV larger than that formed at 350 °C. The higher band-gap energy for 500 °C oxidation is mainly attributable to the higher atomic density of the SiO2 layer of 2.46 × 1022/cm3. Another reason may be the absence of SiO2 trap-states. 相似文献
997.
Masao Kamiko Atsuhito Nakamura Kazuaki Aotani Ryoichi Yamamoto 《Applied Surface Science》2009,256(4):1257-1260
The influence of a Bi surfactant layer on the structural and magnetic properties of Co/Cu multilayers grown onto Cu(1 1 0) buffer layer by RF magnetron sputtering has been studied. The results of X-ray diffraction revealed the initial deposition of a 2.0 Å-thick Bi layer onto the Cu buffer layer prior to the deposition of the Co/Cu multilayer yielded high-quality fcc-(1 1 0) oriented epitaxial films. The X-ray photoelectron spectra revealed that Bi was segregated at around the top of the surface. Therefore, Bi was concluded to be an effective surfactant to enhance the epitaxial growth of Co/Cu(1 1 0) multilayer. The maximum giant magnetoresistance and antiferromagnetic interlayer coupling ratios of the Co/Cu multilayers were increased by using the Bi surfactant layer. 相似文献
998.
Sarkar M. Abe Kawsar Imtiaj Hasan Sultana Rajia Yasuhiro Koide Yuki Fujii Ryuhei Hayashi Masao Yamada Yasuhiro Ozeki 《Molecules (Basel, Switzerland)》2021,26(16)
Lectins facilitate cell–cell contact and are critical in many cellular processes. Studying lectins may help us understand the mechanisms underlying tissue regeneration. We investigated the localization of an R-type lectin in a marine annelid (Perinereis sp.) with remarkable tissue regeneration abilities. Perinereis nuntia lectin (PnL), a galactose-binding lectin with repeating Gln-X-Trp motifs, is derived from the ricin B-chain. An antiserum was raised against PnL to specifically detect a 32-kDa lectin in the crude extracts from homogenized lugworms. The antiserum detected PnL in the epidermis, setae, oblique muscle, acicula, nerve cord, and nephridium of the annelid. Some of these tissues and organs also produced Galactose (Gal) or N-acetylgalactosamine (GalNAc), which was detected by fluorescent-labeled plant lectin. These results indicated that the PnL was produced in the tissues originating from the endoderm, mesoderm, and ectoderm. Besides, the localizing pattern of PnL partially merged with the binding pattern of a fluorescent-labeled mushroom lectin that binds to Gal and GalNAc. It suggested that PnL co-localized with galactose-containing glycans in Annelid tissue; this might be the reason PnL needed to be extracted with haptenic sugar, such as d-galactose, in the buffer. Furthermore, we found that a fluorescein isothiocyanate-labeled Gal/GalNAc-binding mushroom lectin binding pattern in the annelid tissue overlapped with the localizing pattern of PnL. These findings suggest that lectin functions by interacting with Gal-containing glycoconjugates in the tissues. 相似文献
999.
Takafumi Fukushima Toshiyuki Oyama Takao Iijima Masao Tomoi Hiroshi Itatani 《Journal of polymer science. Part A, Polymer chemistry》2001,39(19):3451-3463
A soluble multiblock copolyimide without specific functional groups such as OH and COOH was prepared by a direct one‐pot polycondensation of two types of dianhydrides and diamines in the presence of γ‐valerolactone/pyridine catalyst using N‐methylpyrrolidone (NMP)/toluene mixture as a solvent. The polyimide film containing the photosensitive agent diazonaphthoquinone (DNQ) compound gave positive‐tone behavior by UV irradiation, followed by development in a mixture of ethanolamine/NMP/H2O (1/1/1 by weight). The scanning electron microscopic photograph of the resultant image showed fine patterns with about 20 μm film thickness. Its pattern forming was based on the photorearrangement of diazonaphthoquinone, a process in which the ring‐opening reaction of imide units of the polyimide with the amine used as a developer and the following degradation of the polymer are induced. Such a new imaging technique combines principles of photolithography and etching of a polyimide to give, what we call, reaction development patterning in which the main chemical reactions directly related to the pattern formation occur during development. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3451–3463, 2001 相似文献
1000.
When the esters of arylboronic acids with 2,2-dimethylpropan-1,3-diol were treated with a catalytic amount of [Rh(OH)(cod)]2 in the presence of 1,3-bis(diphenylphosphino)propane and CsF in dioxane at 60 degrees C under carbon dioxide atmosphere, the benzoic acid derivatives were obtained in good yields. Reactions of alkenylboronic esters also proceeded under similar conditions to give alpha,beta-unsaturated carboxylic acids. As these boronic esters are now easily available through coupling or direct borylation reactions, this method would be a useful method for the preparation of various functionalized aryl- and alkenyl-carboxylic acids. 相似文献