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101.
102.
L. G. M. Pettersson 《Theoretical chemistry accounts》1994,87(4-5):293-305
Summary The interaction between NO and different possible adsorption sites of the NiO(100) surface is studied. The Ni2+ cation gives a bonding to NO in reasonable agreement with experiment, but only if a crystal potential corresponding to less than completely ionic charges is assumed. The computed angle of 43° is also in good agreement with experiment. O1– sites in both weak and strong crystal potentials also give a strong interaction with NO, 1.3 and 0.5 eV, respectively. In this case the angle is larger or around 70°. The O2– anion and Ni1+ sites do not give any significant bonding irrespective of assumed crystal potential and can be excluded as adsorption sites. The computed vibrational frequency for the adsorbed NO show shifts of +50, –85 and –200 cm–1 for adsorption on Ni2+ in the weak potential, and O1– in strong and weak potential, respectively. Only one, downwards shifted, frequency has been observed in the experiment but the most likely candidate for the experimentally observed adsorption site with a binding of 0.5 eV, is still the Ni2+ in a weak potential. Nitrogen core level shifts are also computed and discussed and the fully screened core-hole state is obtained for a cluster model, NiF4O+NO, of Ni2+ in NiO with an ionicity lower than the standard ± 2.This work is dedicated to Prof. Inga Fischer-Hjalmars 相似文献
103.
Kiviniemi T Pettersson M Khriachtchev L Räsänen M Runeberg N 《The Journal of chemical physics》2004,121(4):1839-1848
IR spectroscopy, laser induced fluorescence (LIF), and thermoluminescence (TL) measurements have been combined to monitor trapping, thermal mobility, and reactions of oxygen atoms in solid xenon. HXeO and O(3) have been used as IR active species that probe the reactions of oxygen atoms. N(2)O and H(2)O have been used as precursors for oxygen atoms by photolysis at 193 nm. Upon annealing of matrices after photolysis, ozone forms at two different temperatures: at 18-24 K from close O ...O(2) pairs and at approximately 27 K due to global mobility of oxygen atoms. HXeO forms at approximately 30 K reliably at higher temperature than ozone. Both LIF and TL show activation of oxygen atoms around 30 K. Irradiation at 240 nm after the photolysis at 193 nm depletes the oxygen atom emission at 750 nm and reduces the amount of HXeO generated in subsequent annealing. Part of the 750 nm emission can be regenerated by 266 nm and this process increases the yield of HXeO in annealing as well. Thus, we connect oxygen atoms emitting at 750 nm with annealing-induced formation of HXeO radicals. Ab initio calculations at the CCSD(T)/cc-pV5Z level show that XeO (1(1)Sigma(+)) is much more deeply bound [D(e) = 1.62 eV for XeO --> Xe+O((1)D)] than previous calculations have predicted. Taking into account the interactions with the medium in an approximate way, it is estimated that XeO (1(1)Sigma(+)) has a similar energy in solid xenon as compared with interstitially trapped O((3)P) suggesting that both possibly coexist in a low temperature solid. Taking into account the computational results and the behavior of HXeO and O(3) in annealing and irradiations, it is suggested that HXeO may be formed from singlet oxygen atoms which are trapped in a solid as XeO (1(1)Sigma(+)). 相似文献
104.
Jensen MB Pettersson LG Swang O Olsbye U 《The journal of physical chemistry. B》2005,109(35):16774-16781
A comparative quantum chemical study of CO2 adsorption on MgO and CaO has been carried out. Theoretical infrared (IR) frequencies are calculated and compared with IR experiments from the literature. The results show that CO2 adsorbs as monodentate on edge sites and bidentate on corner sites on MgO. The former assignment contradicts the common assumption of adsorption of CO2 in a bidentate configuration. On CaO, CO2 adsorbs as monodentate on both edge and corner sites, which is a reinterpretation of earlier experimental work. On terrace (100) sites, none of the adsorption modes on MgO or CaO possess calculated frequencies in agreement with the experimental IR spectra. These experimental bands were tentatively assigned to some slightly perturbed double negatively charged carbonate ions at the surface, rather than the monodentate structure suggested in the literature. 相似文献
105.
P. P. Povinec M. K. Pham J. A. Sanchez-Cabeza G. Barci-Funel R. Bojanowski T. Boshkova W. C. Burnett F. Carvalho B. Chapeyron I. L. Cunha H. Dahlgaard N. Galabov L. K. Fifield J. Gastaud J. -J. Geering I. F. Gomez N. Green T. Hamilton F. L. Ibanez M. Ibn Majah M. John G. Kanisch T. C. Kenna M. Kloster M. Korun L. Liong Wee Kwong J. La Rosa S. -H. Lee I. Levy-Palomo M. Malatova Y. Maruo P. Mitchell I. V. Murciano R. Nelson A. Nouredine J. -S. Oh B. Oregioni G. Le Petit H. B. L. Pettersson A. Reineking P. A. Smedley A. Suckow T. D. B. van der Struijs P. I. Voors K. Yoshimizu E. Wyse 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(2):383-393
A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa
Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides
(40K, 60Co, 155Eu, 230Th, 238U, 238Pu, 239+240Pu and 241Am). Information values are given for 12 radionuclides (90Sr, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 232Th, 234U, 235U, 239Pu, 240Pu and 241Pu). Less reported radionuclides include 228Th, 236U, 239Np and 242Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides
in the environment, as well as for the development and validation of analytical methods and for training purposes. The material
is available from IAEA in 100 g units.
Retired from IAEA in 2003. 相似文献
106.
Dahlin AP Wetterhall M Liljegren G Bergström SK Andrén P Nyholm L Markides KE Bergquist J 《The Analyst》2005,130(2):193-199
Hybrid capillary-poly(dimethysiloxane)(PDMS) microchips with integrated electrospray ionization (ESI) tips were directly fabricated by casting PDMS in a mould. The shapes of the emitter tips were drilled into the mould, which produced highly reproducible three-dimensional tips. Due to the fabrication method of the microfluidic devices, no sealing was necessary and it was possible to produce a perfect channel modified by PolyE-323, an aliphatic polyamine coating agent. A variety of different coating procedures were also evaluated for the outside of the emitter tip. Dusting graphite on a thin unpolymerised PDMS layer followed by polymerisation was proven to be the most suitable procedure. The emitter tips showed excellent electrochemical properties and durabilities. The coating of the emitter was eventually passivated, but not lost, and could be regenerated by electrochemical means. The excellent electrochemical stability was further confirmed in long term electrospray experiments, in which the emitter sprayed continuously for more than 180 h. The PolyE-323 was found suitable for systems that integrate rigid fused silica and soft PDMS technology, since it simply could be applied successfully to both materials. The spray stability was confirmed from the recording of a total ion chromatogram in which the electrospray current exhibited a relative standard deviation of 3.9% for a 30 min run. CE-ESI-MS separations of peptides were carried out within 2 min using the hybrid PDMS chip resulting in similar efficiencies as for fused silica capillaries of the same length and thus with no measurable band broadening effects, originating from the PDMS emitter. 相似文献
107.
N-Benzoxycarbonylglycyl-L-proline (L-ZGP) has been introduced as a chiral selector for enantioseparation of amines in non-aqueous capillary electrophoresis. Methanol mixed with different proportions of dichloromethane, 1,2-dichloroethane or 2-propanol containing L-ZGP and ammonium acetate was used as the background electrolyte. Enantioseparation of different types of pharmacologically active amines was performed, e.g. the local anaesthetic bupivacaine and the beta-adrenoceptor blocking agent pindolol. Addition of the solvents (dichloromethane, 1,2-dichloroethane or 2-propanol) gave an improved chiral separation partly due to a distinct decrease in the electroosmotic flow. The use of 1,2-dichloroethane in the background electrolyte gave higher precision in migration time (RSD 2.2%) compared to the systems containing dichloromethane. An enantiomeric separation of mepivacaine was performed within 72 s by use of short-end injection with an effective capillary length of 8.5 cm. 相似文献
108.
(-)-2,3:4,6-Di-O-isopropylidene-2-keto-L-gulonic acid [(-)-DIKGA] has been introduced as a chiral counter ion in non-aqueous capillary electrophoresis. High enantioresolutions (R(s)> or =3) were obtained for amines, e.g., pronethalol, labetalol and bambuterol. Methanol containing NaOH and (-)-DIKGA was used as the background electrolyte. The counter ion concentration and the nature of the injection medium were found to affect the chiral separation. Covalent coating of the fused-silica capillary reduced the electro-osmotic flow resulting in improved enantioresolutions. 相似文献
109.
N. v. Klobukow L. F. Nilson Otto Pettersson Gerhard Krüss J. Meunier W. La Coste C. Schall Gibson Dyson W. Bott D. S. Macnair Hans Malfatti Paul Schoop N. Menschutkin D. Konowalow Victor Meyer G. G. Pond Wladimir Alexeew V. Meyer T. P. Bruce Warren und W. Jäger 《Fresenius' Journal of Analytical Chemistry》1888,27(1):194-203
Ohne Zusammenfassung 相似文献
110.
Otto Pettersson 《Fresenius' Journal of Analytical Chemistry》1873,12(1):287-289
Ohne Zusammenfassung 相似文献