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排序方式: 共有144条查询结果,搜索用时 31 毫秒
1.
Leszek Wachowski Antoni Grodzicki Piotr Piszczek Monika Richert Magdalena Hofman 《Reaction Kinetics and Catalysis Letters》2007,91(1):93-99
Hydrogenation of styrene has been applied as a test reaction to study the catalytic activity of TiO2 deposited by the CVD (chemical vapour deposition) method on the surface of a carbonaceous material enriched in nitrogen (CN). 相似文献
2.
VOXO4 systems have been considered as potential lithium battery electrodes. They mainly present two distinct structural types: the tetragonal “α” type with a two-dimensional framework, and the three-dimensional orthorhombic “β”. DFT calculations were performed on this latter system for several β-LixVOXO4 compounds (x=0, 1; X=P, As, S). They allowed to propose structural models for VOAsO4 and LiVOSO4, not fully crystallographically well described yet. Based on an experimental model of two-phase processes, these calculations led also to a good simulation of electrochemical potential values. A density of states analysis put in evidence the “inductive effect” and the role played by (XO4)n− groups inside the host frameworks on these potentials. 相似文献
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4.
Laurent De Windt Detlef W. M. Hofman Lorenzo Pisani Enrico Clementi 《International journal of quantum chemistry》1995,53(2):131-147
The Coulomb–Hole–Hartree–Fock method introduced by E. Clementi in the early 1960s and reparametrized more recently by S. Chakraworty and E. Clementi to compute the correlated electronic energy in atomic systems, is here extended to compute molecules. The new parametrization is obtained empirically by fitting first and second atomic ionization potentials from He to Ca and a few diatomic molecules. The present formulation makes use of either one or more determinants in order to ensure proper dissociation products, following the early proposal of G.C. Lie and E. Clementi in the context of density functional computations for molecular systems. The new formulation is tested against the dissociation energies of a large number of molecules and it is found satisfactory. © 1995 John Wiley & Sons, Inc. 相似文献
5.
Barbara Marciniec M. Stawny Magdalena Hofman M. Naskrent 《Journal of Thermal Analysis and Calorimetry》2008,93(3):733-737
The study has been undertaken to check the effect of ionising radiation on the physical and chemical properties of florfenicol,
an antibiotic of a wide range of antibacterial activity. The solid-state samples were subjected to an electron beam generated
by accelerator corresponding to the doses of 25, 100 and 400 kGy, and the effect of the exposure was analysed by the methods
not requiring changes in the state (with no preliminary treatment), such as SEM, DSC, FTIR, XRD, EPR and HPLC.
Florfenicol irradiated with a dose of 25 kGy has not changed the form or colour, however, a small increase in intensity of
some absorption bands in the FTIR spectrum and of some peaks in the XRD pattern, a decrease in the melting point by 0.6°C,
the appearance of free radicals and a loss in the FF content within the error of the method (0.91%) have been observed. After
irradiation with greater doses (100 and 400 kGy) the changes have intensified, yellow discolouration appeared and the loss
of FF content has increased to 6.39%. As follows from the results, the compound studied in solid-state undergoes radiolysis
after e-beam irradiation in the doses ≥25 kGy, but lower doses (15–20 kGy) can be applied for its decontamination or sterilization
with no adverse effect on its physico-chemical properties. 相似文献
6.
Gerard van Doremaele Martin van Duin Maxence Valla Alexandra Berthoud 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):2877-2891
ARLANXEO Elastomers has developed and commercialized Keltan ACE™ technology, a class of half-sandwich cyclopentadienyl κ1-amidinate metal complexes, which are extremely active for the production of first-class ethylene/propylene/diene copolymers (EPDM). In this review, the development and some of the key features of the Keltan ACE™ catalyst system are presented. Many different ACE catalysts have been synthesized over the past years, including bridged and bimetallic catalysts. With Keltan ACE™, a complete range of EPDM products with similar polymer characteristics as their Ziegler–Natta (ZN) counterparts can be produced, including variations containing very high 5-ethylidene-2-norbornene (ENB) contents, controlled long chain branching, very high molecular weight, as well as oil-extended products. Moreover, other EPDM structures can be polymerized. The Keltan ACE™ catalyst technology also allows the production of EPDMs with very high amounts of dicyclopentadiene (DCPD) or 5-vinyl 2-norbornene (VNB) without excessive gelation and reactor fouling, that is, products that cannot or are extremely difficult to obtain via classical ZN catalysis. In a next step, high-VNB-EPDM can be postreactor modified, for example, via metathesis chemistry. In addition, EPDM polymers with a very broad or even bimodal molecular weight distribution can be obtained in a single reactor with certain ACE catalyst structures at particular activator/precatalyst ratios. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2877–2891 相似文献
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8.
Back BB Baker MD Ballintijn M Barton DS Becker B Betts RR Bickley AA Bindel R Budzanowski A Busza W Carroll A Decowski MP García E Gburek T George N Gulbrandsen K Gushue S Halliwell C Hamblen J Harrington AS Henderson C Hofman DJ Hollis RS Hołyński R Holzman B Iordanova A Johnson E Kane JL Khan N Kulinich P Kuo CM Lee JW Lin WT Manly S Mignerey AC Noell A Nouicer R Olszewski A Pak R Park IC Pernegger H Reed C Remsberg LP Roland C Roland G Sagerer J Sarin P Sawicki P Sedykh I Skulski W Smith CE 《Physical review letters》2003,91(7):072302
We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at sqrt[s(NN)]=200 GeV. The spectra were obtained for transverse momenta 0.25
相似文献
9.
Baryon rapidity loss in relativistic Au + Au collisions 总被引:4,自引:0,他引:4
Back BB Betts RR Chang J Chang WC Chi CY Chu YY Cumming JB Dunlop JC Eldredge W Fung SY Ganz R Garcia E Gillitzer A Heintzelman G Henning WF Hofman DJ Holzman B Kang JH Kim EJ Kim SY Kwon Y McLeod D Mignerey AC Moulson M Nanal V Ogilvie CA Pak R Ruangma A Russ DE Seto RK Stanskas PJ Stephans GS Wang HQ Wolfs FL Wuosmaa AH Xiang H Xu GH Yao HB Zou CM 《Physical review letters》2001,86(10):1970-1973
An excitation function of proton rapidity distributions for different centralities is reported from AGS Experiment E917 for Au+Au collisions at 6, 8, and 10.8 GeV/nucleon. The rapidity distributions from peripheral collisions have a valley at midrapidity which smoothly change to distributions that display a broad peak at midrapidity for central collisions. The mean rapidity loss increases with increasing beam energy, whereas the fraction of protons consistent with isotropic emission from a stationary source at midrapidity decreases with increasing beam energy. The data suggest that the stopping is substantially less than complete at these energies. 相似文献
10.
Kwok WK Olsson RJ Karapetrov G Paulius LM Moulton WG Hofman DJ Crabtree GW 《Physical review letters》2000,84(16):3706-3709
The critical points in untwinned YBa(2)Cu(3)O(7-delta) crystals with dilute columnar defects are investigated. We find a convergence of a first order vortex melting line with an irreversibility line associated with the onset of the Bose glass critical regime at the lower critical point. In addition, we find that columnar defects raise the upper critical point, implying that vortex line meandering is a basic feature controlling its position. 相似文献