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61.
Koichi Hatada Koichi Ute Tatsuki Kitayama Takafumi Nishiura Nobuo Miyatake 《Macromolecular Symposia》1994,85(1):325-338
Highly isotactic (it-) and highly syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) uniform with respect to molecular weight (stereoregular, uniform PMMAs) were isolated up to the 100mer from it- and st-PMMAs by supercritical fluid chromatography (SFC) and characterized by NMR and mass spectroscopies. Glass transition temperatures (Tg's) of the uniform it- and st-PMMAs were higher than those of the corresponding PMMAs with MWD and with similar molecular weight on average. The Tg values of the uniform it-and st-PMMAs series obeyed the relationship, Tg = Tg∞ - K/M, where M and Tg∞ denote molecular weight and Tg at infinite M, respectively. The reciprocal melting points (1/Tm) of uniform it-PMMA (degree of polymerization, DP = 28–44), obtained from methanol solutions by evaporating the solvent, increased linearly with increasing 1/DP. Extrapolation of the linear relation to 1/DP = 0 gave the Tm of it-PMMA with infinite DP; Tm∞ = 171.1°C. Thermal degradation behavior was studied by thermogravimetry and by SFC analysis of degradation products. In gel-permeation chromatography (GPC) measurements, the it-50mer eluted faster than the st-50mer. Calibration curves for it- and st-PMMAs could be obtained using series of the uniform PMMAs. The instrumental spreading factor determined using it-25mer, it-50mer, st-25mer and st-50mer for our GPC chromatograph was 0.070 ml when the volume of the sample solution was 0.003ml. GPC analysis of a mixture of the it- and st-50mers in tetrahydrofuran indicated formation of a stereocomplex in the solution, and was found quite useful to elucidate the minimum sequence length required for complex formation. 相似文献
62.
K. Asahi H. Okuno H. Ueno H. Sato J. Kura T. Kubo T. Nakamura N. Inabe A. Yoshida Y. Ohkubo M. Adachi T. Ichihara M. Ishihara T. Shimoda H. Miyatake N. Takahashi D. Beaumel D. J. Morrissey W. -D. Schmidt-Ott 《Hyperfine Interactions》1992,75(1-4):101-108
Ejectile nuclei in the fragmentation of intermediate-energy heavy-ion projectiles were found to be largely spin polarized.
The observed polarization as a function of the outgoing momentum was nicely explained by a simple kinematical argument based
on the participant-spectator model of projectile fragmentation. The measurements extended to cover several different targets,
incident energies, exit channels, and emission angles revealed that substantial polarization shows up widely in projectile
fragmentation reactions. Furthermore, this polarization exhibits an interesting behavior which may be interpreted as a manifestation
of a gradual change in the deflection angle from positive to negative values as the energy increases and/or the target-Z decreases. The present polarization results also suggests various applications of spin polarized radioactive beams. As the
first example of such an application, we present a recent result on theg-factor measurements on neutron-rich nuclei. 相似文献
63.
S. Kubono Y. Funatsu N. Ikeda M. Yasue T. Nomura Y. Fuchi H. Kawashima S. Kato H. Orihara H. Miyatake T. Kajino 《Zeitschrift für Physik A Hadrons and Nuclei》1989,334(4):511-512
More than ten new levels have been identified just above the proton threshold in21Mg. The lowest s-wave resonant state assumed previously for the calculation of the stellar reaction rate in the rp-process is found to be a bound state, suggesting a serious change for the early stage of the rp-process. 相似文献
64.
N. Aoi K. Yoneda H. Miyatake H. Ogawa Y. Yamamoto E. Ideguchi T. Kishida T. Nakamura M. Notani H. Sakurai T. Teranishi H. Wu S. S. Yamamoto Y. Watanabe A. Yoshida M. Ishihara 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(2):253-255
Experimental studies of β-decay measurements of the neutron drip line nuclei 11Li and 14Be are presented. β- decay schemes of these nuclei are determined by measuring β-rays, delayed neutrons and γ-rays in triple coincidence. The decay schemes of both 11Li and 14Be associated with single neutron emission are unambiguously determined. New levels in their daughter nuclei, 11Be and 14B, are found. In addition, the deduced level scheme of 14B indicates the lowering of 2s 1/2 single neutron orbital with respect to 1p 1/2 orbital in the N=9 isotones. Such behavior is known to exist in N=7. 相似文献
65.
Brewer JH Ansaldo EJ Carolan JF Chaklader AC Hardy WN Harshman DR Hayden ME Ishikawa M Kaplan N Keitel R Kempton J Kiefl RF Kossler WJ Kreitzman SR Kulpa A Kuno Y Luke GM Miyatake H Nagamine K Nakazawa Y Nishida N Nishiyama K Ohkuma S Riseman TM Roehmer G Schleger P Shimada D Stronach CE Takabatake T Uemura YJ Watanabe Y Williams DL Yamazaki T Yang B 《Physical review letters》1988,60(11):1073-1076
66.
Total Synthesis and Biological Evaluation of the Glycosylated Macrocyclic Antibiotic Mangrolide A
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Hiromu Hattori Joel Roesslein Dr. Patrick Caspers Dr. Katja Zerbe Dr. Hideki Miyatake‐Ondozabal Dr. Daniel Ritz Dr. Georg Rueedi Prof. Dr. Karl Gademann 《Angewandte Chemie (International ed. in English)》2018,57(34):11020-11024
The macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram‐negative pathogens. Reported is the first enantioselective total synthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two β‐selective glycosylations. The synthesis of mangrolide A and its analogues enabled the re‐examination of its activity against bacterial pathogens, and only minimal activity was observed. 相似文献
67.
Docking Strategy To Construct Thermostable,Single‐Crystalline,Hydrogen‐Bonded Organic Framework with High Surface Area
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Dr. Ichiro Hisaki Yuto Suzuki Eduardo Gomez Dr. Boiko Cohen Dr. Norimitsu Tohnai Prof. Dr. Abderrazzak Douhal 《Angewandte Chemie (International ed. in English)》2018,57(39):12650-12655
Enhancing thermal and chemical durability and increasing surface area are two main directions for the construction and improvement of the performance of porous hydrogen‐bonded organic frameworks (HOFs). Herein, a hexaazatriphenylene (HAT) derivative that possesses six carboxyaryl groups serves as a suitable building block for the systematic construction of thermally and chemically durable HOFs with high surface area through shape‐fitted docking between the HAT cores and interpenetrated three‐dimensional network. A HAT derivative with carboxybiphenyl groups forms a stable single‐crystalline porous HOF that displays protic solvent durability, even in concentrated HCl, heat resistance up to 305 °C, and a high Brunauer–Emmett–Teller surface area [SA(BET)] of 1288 m2 g?1. A single crystal of this HOF displays anisotropic fluorescence, which suggests that it would be applicable to polarized emitters based on robust functional porous materials. 相似文献
68.
Model experiments for a simple and effective trapping device of volatile iodine that is generated during radioiodination of biomacromolecules were performed using an activated carbon fiber filter. Over 99.9% of the radioactivity was trapped by the first sheet, when a stream of the volatile radioactive iodine was passed through the layer consisting of several sheets of carbon fiber filter of pore-size 2nm preceded by two or three sheets of urethane foam filter to eliminate the water vapor. Since the carbon fiber filter has very little resistance to the gas flow, the device seems applicable to the small filter chamber for the radioiodination hood. 相似文献
69.
Kenji Miyatake Mitsutoshi Jikei Kimihisa Yamamoto Hiroyuki Nishide Eishun Tsuchida 《先进技术聚合物》1992,3(7):401-405
The electrophilic reaction of sulfur dichloride with diphenyl sulfide proceeds efficiently at room temperature to yield oligo(phenylene sulfide) in the presence of a catalytic amount of Fe powder. Sulfur dichloride shows higher reactivity than sulfur monochloride. The reaction is promoted through the activation of sulfur dichloride by Fe powder. The polymeric product contains a linear structure linked by disulfide and sulfide bonds. 相似文献
70.
Dazhi Sun Minhao Wong Luyi Sun Yuntao Li Nobuo Miyatake Hung-Jue Sue 《Journal of Sol-Gel Science and Technology》2007,43(2):237-243
Purification and stabilization of colloidal ZnO nanoparticles synthesized from zinc acetate dihydrate and potassium hydroxide
in methanol have been performed. Isopropanol and hexane were utilized to achieve the precipitation-redispersion washing procedure
in methanol. The results from atomic absorption spectroscopy show that the concentration of K+ cation can be dramatically reduced by washing. X-ray diffraction and transmission electron microscopy results show that zinc
layered double hydroxide formed in the ZnO precipitate can be effectively removed through concentrating the unpurified ZnO
colloids by solvent evaporation. The purified ZnO nanoparticles can be fully redispersed in methanol, but become unstable
with time due to the low concentration of acetate in the colloids. Fortunately, the unstable ZnO methanol colloids are found
to become stable after addition of a small amount of hexane. The present study is of particular significance for the preparation
of purified colloidal ZnO nanoparticles for device fabrication, functional ZnO coatings and polymer nanocomposite applications. 相似文献