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111.
112.
Pentafluorophenylammonium triflate(PFPAT) was found to be a highly efficient catalyst for the preparation of 2,4,6- triarylpyridines from the reaction of acetophenone derivatives,aromatic aldehydes and ammonium acetate.Present methodology offers several advantages,such as short reaction time,high yields,simple procedure with an easy work-up and the absence of any volatile and hazardous organic solvent.In addition,this catalytic system can act as an active,inexpensive,metal-free,recoverable and recyclable catalyst. 相似文献
113.
Amin Aziznia Hamid Reza Bozorgzadeh Naser Seyed-Matin Morteza Baghalha Ali Mohamadalizadeh 《天然气化学杂志》2012,(4):466-475
In the current study,the hybrid effect of a corona discharge and γ-alumina supported Ni catalysts in CO2 reforming of methane is investigated.The study includes both purely catalytic operation in the temperature range of 923-1023K,and hybrid catalytic-plasma operation of DC corona discharge reactor at room temperature and ambient pressure.The effect of feed flow rate,discharge power and Ni/γ-Al2O3 catalysts are studied.When CH4/CO2 ratio in the feed is 1/2,the syngas of low H2/CO ratio at about 0.56 is obtained,which is a potential feedstock for synthesis of liquid hydrocarbons.Although Ni catalyst is only active above 573K,presence of Ni catalysts in the cold corona plasma reactor(T≤523K) shows promising increase in the conversions of methane and carbon dioxide.When Ni catalysts are used in the plasma reaction,H2/CO ratios in the products are slightly modified,selectivity to CO increases whereas fewer by-products such as hydrocarbons and oxygenates are formed. 相似文献
114.
Aluminium‐27 nuclear magnetic resonance spectroscopy (27Al NMR) does not yield fully resolved spectra for end‐group aluminates attached to different silicate species. For example, the chemical shifts of all q1 (end‐group aluminates) lying in the range δ ≈ 72.2–77 ppm are observed on average at δ ≈ 74.6 ppm in an NMR spectrum. With the aim of better characterisation of different q1 linked units, we first made some attempts to resolve the signals that might arise from different q1 linkages through the application of suitable experimental methods and then followed up this work by applying some calculation methods. Some of the observed differences and evidence have not been previously detected experimentally, but were clearly apparent from our calculations (Table 1) as well as in our experimental data. Therefore, in such a situation, theoretical calculations of NMR chemical shifts can be very helpful and can provide some missing information. 相似文献
115.
Mehdi Vahidi Naser Seyed Matin Mahdi Goharrokhi Masih Hosseini Jenab Majid Abedinzadegan Abdi Seyed Hesam Najibi 《The Journal of chemical thermodynamics》2009,41(11):1272-1278
Solubility data of CO2 in aqueous N-methyldiethanolamine (MDEA) solutions of concentration (2.52, 3.36, and 4.28) kmol/m3 were obtained at temperatures (313, 323, and 343) K and partial pressures ranging from about (30 to 5000) kPa. A thermodynamic model based on extended Debye–Hückel theory was applied to predict and correlate of CO2 solubility in various aqueous amine solutions. The effect of piperazine (PZ) concentration on CO2 loading in MDEA solutions was determined at PZ concentration (0.36, 0.86, and 1.36) kmol/m3. Using experimental data in various temperatures the interaction parameters of activity coefficient model for these systems were determined. The results show the model consistency with experimental and literature data and PZ is beneficial to the CO2 loading. The comparison of results of this study with previous data work shows the wide range of CO2 loading considered in this work and the better agreement of model with experimental data. The average absolute relative deviation percent (δAAD) for all data points were 8.11%. 相似文献
116.
Naser Foroughifar Akbar Mobinikhaledi Sattar Ebrahimi Hassan Moghanian Mohammad Ali Bodaghi Fard Mehdi Kalhor 《Tetrahedron letters》2009,50(7):836-598
A series of new 1,2/1,3-bis[o-(N-methylidenamino-5-aryl-3-thiol-4H-1,2,4-triazole-4-yl)phenoxy]alkane derivatives 3a-d and bis[o-(N-methylidenamino-2-thiol-1,3,4-thiadiazole-5-yl)phenoxy]alkanes 6a-c were prepared by condensation of 4-amino-5-(aroyl)-4H-1,2,4-triazole-3-thiols 2a-b or 2-amino-5-mercapto-1,3,4-thiadiazole with bis-aldehydes 1a-c. Further reaction of compounds 3a-d and 6a-c with dibromoalkanes afforded the new macrocycles 5a-f and 8a-d. The cyclization does not require high dilution techniques and provides the expected azathia macrocycles in good yields, ranging from 55% to 68%. 相似文献
117.
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119.
Solubility and diffusion of CO2 and H2S in the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate
Amir Hossein Jalili Ali Mehdizadeh Mohammad Shokouhi Amir Naser Ahmadi Masih Hosseini-Jenab Fakhrolsadat Fateminassab 《The Journal of chemical thermodynamics》2010,42(10):1298-1303
The solubility and diffusion coefficient were determined for carbon dioxide and hydrogen sulfide gases in the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) at temperatures ranging from (303.15 to 353.15) K and pressures up to 1.6 MPa. The Krichevsky–Kasarnovsky equation was used to correlate solubility data and Henry’s law constants at different temperatures were obtained. The partial molar thermodynamic functions of solution such as Gibbs free energy, enthalpy, and entropy were calculated using the solubility data. A semi-infinite volume approach is used to obtain the diffusion coefficients for CO2 and H2S and a correlation equation with temperature is presented for each gas. Comparison showed that H2S is more soluble than CO2 and its diffusion coefficient is about two orders of magnitude as that of CO2 in the ionic liquid studied in this work. 相似文献
120.
Häller LJ Page MJ Erhardt S Macgregor SA Mahon MF Naser MA Vélez A Whittlesey MK 《Journal of the American Chemical Society》2010,132(51):18408-18416
A combination of experimental studies and density functional theory calculations is used to study C-N bond activation in a series of ruthenium N-alkyl-substituted heterocyclic carbene (NHC) complexes. These show that prior C-H activation of the NHC ligand renders the system susceptible to irreversible C-N activation. In the presence of a source of HCl, C-H activated Ru(I(i)Pr(2)Me(2))'(PPh(3))(2)(CO)H (1, I(i)Pr(2)Me(2) = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) reacts to give Ru(I(i)PrHMe(2))(PPh(3))(2)(CO)HCl (2, I(i)PrHMe(2) = 1-isopropyl-4,5-dimethylimidazol-2-ylidene) and propene. The mechanism involves (i) isomerization to a trans-phosphine isomer, 1c, in which hydride is trans to the metalated alkyl arm, (ii) C-N cleavage to give an intermediate propene complex with a C2-metalated imidazole ligand, and (iii) N-protonation and propene/Cl(-) substitution to give 2. The overall computed activation barrier (ΔE(++)(calcd)) corresponds to the isomerization/C-N cleavage process and has a value of +24.4 kcal/mol. C-N activation in 1c is promoted by the relief of electronic strain arising from the trans disposition of the high-trans-influence hydride and alkyl ligands. Experimental studies on analogues of 1 with different C4/C5 carbene backbone substituents (Ru(I(i)Pr(2)Ph(2))'(PPh(3))(2)(CO)H, Ru(I(i)Pr(2))'(PPh(3))(2)(CO)H) or different N-substituents (Ru(IEt(2)Me(2))'(PPh(3))(2)(CO)H) reveal that Ph substituents promote C-N activation. Calculations confirm that Ru(I(i)Pr(2)Ph(2))'(PPh(3))(2)(CO)H undergoes isomerization/C-N bond cleavage with a low barrier of only +21.4 kcal/mol. Larger N-alkyl groups also facilitate C-N bond activation (Ru(I(t)Bu(2)Me(2))'(PPh(3))(2)(CO)H, ΔE(++)(calcd) = +21.3 kcal/mol), and in this case the reaction is promoted by the formation of the more highly substituted 2-methylpropene. 相似文献