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81.
82.
Makiko Asamoto Shinji Miyake Kazunari Sugihara Hidenori Yahiro 《Electrochemistry communications》2009,11(7):1508-1511
The anodic performances of Ni/CeO2–Sm2O3(Ni/SDC) modified by the addition of alkaline earth metal oxides (MgO, CaO, and SrO) were investigated for direct oxidation of CH4 in solid oxide fuel cells (SOFCs). Although the initial power density of cell with Ni/SDC anode modified by the addition of CaO was slightly lower than that of cell with Ni/SDC, the former anode exhibited an excellent stability compared to the latter one. Such a high stability of Ni–CaO/SDC anode may come from the inhibition of carbon deposition in addition to the retained ionic conductivity of anode. 相似文献
83.
Naik SP Fan W Yokoi T Okubo T 《Langmuir : the ACS journal of surfaces and colloids》2006,22(14):6391-6397
We demonstrate a robust approach to the synthesis of a 3D cubic Im3m mesoporous silica monolith from SiO2/cetyltrimethylammoniumbromide (CTAB)/1,3,5-triisopropylbenzene (TIPB) sols having molar compositions of 1SiO2/0.0017HCl/5.2H2O/10EtOH/0.10CTAB/0.1-0.5TIPB by the evaporation-induced self-assembly (EISA) process. The addition of TIPB is aimed at altering the micelle geometry to spheroid from rodlike in the gel state; the change in micelle geometry leads to the formation of a 3D cage-type cubic mesostructure in the monolith. The synthesized materials exhibit BET surface areas of 800-1000 m(2)/g, a BJH pore diameter of 2.9-4.3 nm, and a pore volume of 0.7-1.0 cm(3)/g, demonstrating ultrahigh porosity of the 3D cubic mesostructure. 相似文献
84.
Hidenori Hanaoka 《Journal of organometallic chemistry》2006,691(23):4968-4974
Phosphorous-bridged bisphenoxy titanium complexes were synthesized and their ethylene polymerization behavior was investigated. Bis[3-tert-butyl-5-methyl-2-phenoxy](phenyl)phosphine tetrahydrofuran titanium dichloride (4a) was obtained by treatment of 3 equiv of n-BuLi with bis[3-tert-butyl-2-hydroxy-5-methylphenyl](phenyl)phosphine hydrochloride salt (3a) followed by TiCl4(THF)2 in THF. THF-free complexes 5a-5d were synthesized more conveniently by the direct reaction of MOM-protected ligands (2a-2d) with TiCl4 in toluene. X-ray analysis of 4a revealed that the ligand is bonded to the octahedral titanium (IV) center in a facial fashion and two chlorine atoms possess cis-geometry. Complexes 4a and 5a-5d were utilized as catalyst precursors for ethylene polymerization. Complex 5c gave high molecular weight polyethylene (Mw = 1,170,000, Mw/Mn = 2.0) upon activation with Al(iBu)3/[Ph3C][B(C6F5)4] (TB). Ethylene polymerization activity of 5d activated with Al(iBu)3/TB reached 49.0 × 106 g mol (cat) −1 h−1. 相似文献
85.
Payette JN Honda T Yoshizawa H Favaloro FG Gribble GW 《The Journal of organic chemistry》2006,71(1):416-419
[reaction: see text] We have proposed a pathway for the base-catalyzed reverse vinylogous aldol reaction of (-)-(4abeta,5beta)-4,4a,5,6,7,8-hexahydro-5-hydroxy-1,4a-dimethylnaphthalen-2(3H)-one [(-)-8] under Robinson annulation conditions. For confirmation, 4-(2,6-dimethyl-3-oxocyclohex-1-enyl)butanal (11) and 4-(2,6-dimethyl-5-oxocyclohex-1-enyl)butanal (12), both of which potentially produce enolate I, were synthesized regioselectively. Unexpectedly, 11 gave a complex mixture, including only a trace amount of (+/-)-8 (less than 5% yield), under these basic conditions. To the contrary, 12 cleanly afforded (+/-)-8 in 66% yield. This result provides evidence for our proposed mechanism of the above reaction. 相似文献
86.
We report the generation of a continuous-wave squeezed vacuum resonant on the Rb D1 line (795 nm) using periodically poled KTiOPO4 (PPKTP) crystals. With a frequency doubler and an optical parametric oscillator based on PPKTP crystals, we observed a squeezing level of -2.75+/-0.14 dB and an antisqueezing level of +7.00+/-0.13 dB. This system could be utilized for demonstrating storage and retrieval of the squeezed vacuum, which is important for the ultraprecise measurement of atomic spins as well as quantum information processing. 相似文献
87.
Eisaku Ohashi Sangita Karanjit Atsushi Nakayama Kohei Takeuchi Sherif E. Emam Hidenori Ando Tatsuhiro Ishida Kosuke Namba 《Chemical science》2021,12(36):12201
Palau''amine has received a great deal of attention as an attractive synthetic target due to its intriguing molecular architecture and significant immunosuppressive activity, and we achieved its total synthesis in 2015. However, the synthesized palau''amine has not been readily applicable to the mechanistic study of immunosuppressive activity, because it requires 45 longest linear steps from a commercially available compound. Here, we report the short-step construction of the ABCDEF hexacyclic ring core of palau''amine. The construction of the CDE tricyclic ring core in a single step is achieved by our pKa concept for proceeding with unfavorable equilibrium reactions, and a palau''amine analog without the aminomethyl and chloride groups is synthesized in 20 longest linear steps from the same starting material. The palau''amine analog is confirmed to retain the immunosuppressive activity. The present synthetic approach for a palau''amine analog has the potential for use in the development of palau''amine probes for mechanistic elucidation.A palau''amine analog (2) was synthesized from 2-cyclopentenone in 20 steps. The construction of the CDE tricyclic ring core in a single step is achieved by our pKa concept for proceeding with the unfavorable equilibrium reactions. 相似文献
88.
Water imbibition during the waterflooding process of oil production only sweeps part of the oil present. After water disrupts
the oil continuity, most oil blobs are trapped in porous rock by capillary forces. Developing an efficient waterflooding scheme
is a difficult task; therefore, an understanding of the oil trapping mechanism in porous rock is necessary from a microscopic
viewpoint. The development of microfocused X-ray CT scanner technology enables the three-dimensional visualization of multiphase
phenomena in a pore-scale. We scanned packed glass beads filled with a nonwetting phase (NWP) and injected wetting phase (WP)
in upward and downward injections to determine the microscopic mechanism of immiscible displacement in porous media and the
effects of buoyancy forces. We observed the imbibition phenomena for small capillary numbers to understand the spontaneous
imbibition mechanism in oil recovery. This study is one of the first attempts to use a microfocused X-ray CT scanner for observing
the imbibition and trapping mechanisms. The trapping mechanism in spontaneous imbibition is determined by the pore configuration
causing imbibition speed differences in each channel; these differences can disrupt the oil continuity. Gravity plays an important
role in spontaneous imbibition. In upward injection, the WP flows evenly and oil is trapped in single or small clusters of
pores. In downward injection, the fingering phenomena determine the amount of trapped oil, which is usually in a network scale.
Water breakthrough causes dramatic decrease in the oil extraction rate, resulting in lower oil production efficiency. 相似文献
89.
Yokoi T Kato H Kim IY Kikuta K Kamitakahara M Kawashita M Ohtsuki C 《Dalton transactions (Cambridge, England : 2003)》2012,41(9):2732-2737
Octacalcium phosphates (OCPs) co-incorporated with various molar ratios of succinate and suberate ions were synthesized by wet processing. The interplanar spacings of the (100) planes (d(100)) of OCPs formed in the presence of succinic acid (Suc) or suberic acid (Sub) were larger than those of OCPs formed without addition of a dicarboxylic acid to the reaction solvent. The increases in the interplanar spacings of the (100) planes were caused by substitution of HPO(4)(2-) by dicarboxylate ions. The OCPs with co-incorporated succinate and suberate ions, i.e. solid solutions of OCP with incorporated Suc and Sub, were formed by reactions in the presence of Suc and Sub. When the Suc/(Suc + Sub) values in the starting compositions were in the range 0.45-1.0, Suc was preferentially incorporated into the OCP. In contrast, when the Sub/(Suc + Sub) values in the starting compositions were in the range 0.60-1.0, Sub was preferentially incorporated into the OCP crystals. 相似文献
90.
Hidenori Sato Akihito Yamaguchi Osamu Maida Toshimichi Ito 《Radiation measurements》2012,47(4):266-271
We have developed a prototype of a survey meter combining a CVD diamond detector and silicon detectors to appropriately take temporal measurements of γ-ray radiations over a wide range of the dose rates and to measure high accumulated doses of γ-ray radiations. In order to carry out this, at first, we have studied the radiation hardness of diamond detectors suitably fabricated with high-quality single-crystalline CVD diamond films to confirm that such CVD diamond detectors have greatly superior radiation hardness, compared with commercially available silicon detectors. It is evidenced that the performance of the CVD diamond detector did not significantly change even after heavy γ-ray irradiation of 0.7 MGy while the silicon detectors have a remarkable increase in the dark current, a detection peak shift to the low energy side, and a decrease in detection counts for 5.486-MeV α particles. Due to a size limitation of the CVD diamond detector, such a CVD diamond detector was combined with six commercially available silicon detectors to fabricate a survey meter which can appropriately work under severe irradiation conditions, or, at accumulated doses larger than at least 0.5 MGy and which can cover a wide range of the dose rates from 1 μGy/h to at least 1 kGy/h. The prototype survey meter had a practically useful linearity in this dose rate range. Thus, we have confirmed that such a diamond-Si combined survey meter can be put into practical use. 相似文献