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101.
M.?Němec W.?Zendzian H.?Jelínková J.?K.?Jabczynski J.??ulc L.?Gorajek J.?Kwiatkowski 《Laser Physics》2010,20(3):661-664
The study describes efficient, acousto-optic Q-switching of Er:YAG laser at the 1645 nm eye-safe wavelength. For longitudinal
pumping at wavelength 1532 nm, linear-polarized 10 W Erbium fiber laser radiation was used. The investigated Er:YAG crystals
were 25 and 40 mm long and their Erbium concentration was 0.20 and 0.25%, respectively. For giant pulse generation, a fused
silica acousto-optic modulator was inserted inside the Er:YAG laser oscillator. For a maximum incident pump power of 7.95
W, pulse energy up to 4.1 mJ was generated with pulse duration 34 ns at 500-Hz repetition rate; the corresponding peak power
was 119 kW. 相似文献
102.
Z. Librant J.K. Jabczyński H. W?glarz A. Wajler H. Tomaszewski T. ?ukasiewicz W. ?endzian J. Kwiatkowski 《Opto-Electronics Review》2009,17(1):72-77
Transparent Nd:YAG ceramics were produced by solid.state reaction of high.purity (4N) nanometric oxides powders, i.e., Al2O3, Y2O3 and Nd2O3. After sintering, mean grain sizes of 2% Nd:YAG samples were about 20 μm and their transparency were a bit worse than that
of 0.9% Nd:YAG single crystal. Two types of active elements: rods and slabs were fabricated and characterized in several diode
pumping schemes. In end pumping configuration as a pump source 20.W fiber coupled laser diode operating in low duty cycle
regime (1 ms pump duration/20 Hz) was deployed. In the best case, 3.7 W of output power for 18 W of absorbed pump power, M2 < 1.4 were demonstrated for uncoated ceramics Nd:YAG rod of ϕ 4×3mm size in preliminary experiments. For the ceramics of
two times lower Nd dopant level above 30% slope efficiency was achieved. In case of Nd:YAG ceramic slab side pumped by 600.W
laser diode stack above 12 W was demonstrated with slope efficiency of 3.5%. 相似文献
103.
?. Gorajek J. K. Jabczyński W. ?endzian J. Kwiatkowski H. Jelinkova J. Sulc M. Nemec 《Opto-Electronics Review》2009,17(4):309-317
The aim of work was to characterize a simple oscillator consisted of Tm:YLF crystal end-pumped by a fiber coupled diode laser
and active Q-switch with tunability option. About 7 W with near 35% slope efficiency was demonstrated in a free-running mode.
The divergence angle was about 4.3 mrad and estimated parameter M2 < 1.3. Continuous tuning by means of Lyot’s filter, consisted of 2 quartz plates in the range of 1879.0–1939.4 nm with less
than 1-nm linewidth, was achieved. For the best case (10-ms pump pulse duration, 42-A pump current corresponding to 266 mJ
of pump energy), the Q-switched energy was 10.5 mJ with pulse duration of 22 ns corresponding to near 0.5 MW peak power. The
2.5 W of average power with 12.6-kW peak power and 2000-Hz repetition rate was demonstrated for cw pumping regime. 相似文献
104.
105.
A combined forward—reverse library search routine for low-resolution mass spectra is described. The routine requires binary-coded spectra. Masses and peak intensities are used for spectral comparison. On the basis of three possible search strategies, this routine is adaptable to analytical problems. The program was tested for 25 000 spectra from the ISAS, MSDC and EPA mass spectra libraries. The program is written completely in FORTRAN IV. 相似文献
106.
Veli-Matti Mukkala Marek Kwiatkowski Jouko Kankare Harri Takalo 《Helvetica chimica acta》1993,76(2):893-899
Eight different 2,2′-bipyridine derivatives, i.e. 2, 5, 8, 10, 12, 13, 15 , and 19 (Schemes 1 and 2), were prepared to study the influence of the chelating groups on the luminescence properties of their EuIII and TbIII chelates. According to our luminescence results, 2,2′-(methylenenitrilo)bis(acetic acid) as well as (methylenenitrilo)bis-(methylphosphonic acid) in 6- and 6′-position of 2,2′-bipyridine is a suitable group when developing luminescent markers for bioaffinity assays based on time-resolved luminescence measurement. 相似文献
107.
Equilibrium, FTIR, scanning electron microscopy and small wide angle X-ray scattering studies of chromates adsorption on modified bentonite 总被引:5,自引:0,他引:5
Marek Majdan Oksana Maryuk Stanisaw Pikus Elzbieta Olszewska Ryszard Kwiatkowski Henryk Skrzypek 《Journal of Molecular Structure》2005,740(1-3):203-211
The study presents a discussion about the adsorption mechanism of chromate anions on bentonite modified by hexadecyltrimethylammonium bromide (HDTMA-Br). The formation of alkylammonium chromates: HDTMAHCrO4, (HDTMA)2Cr2O7 and to the lesser extent (HDTMA)2CrO4 at the water–bentonite interface is examined based on the Scanning Electron Microscopy and surface tension measurements. The histograms of HDTMA/Cr(VI) molar ratio on the bentonite surface, found from Scanning Electron Microscopy (SEM) measurements, show that for the majority of points of bentonite surface the value of this ratio is in 1–2 range. FTIR spectra of modified bentonite samples show the change from gauche to trans conformation in the surfactant arrangement in the clay interlayer accompanying its concentration increase.
In turn Small Wide Angle X-Ray Scattering (SWAXS) patterns evidently suggest incorporation of chromate anions into the interlamellar space of bentonite structure. 相似文献
108.
George T. Kwiatkowski George L. Brode James H. Kawakami Albert W. Bedwin 《Journal of polymer science. Part A, Polymer chemistry》1974,12(3):589-601
High temperature thermoplastic polyamide-imides were prepared from a new series of aromatic diamines containing the diphenylsulfone unit and alternatively, oxydiphenyl and diphenylisopropylidene units. The polymers were prepared in their completely imidized form by using a facile in situ chemical imidization reaction which offers several advantages over the conventional thermal imidization process. The sulfone-based polyamide-imides exhibited an excellent combination of moldability, thermal stability, mechanical properties and solvent resistance. Analysis of the properties of these polymers in terms of structural variations permits a useful correlation of the effect of various structural units on performance. The polar diphenyl sulfone and amide-imide units increase the glass transition temperature and improve solvent resistance while the oxydiphenyl and diphenylisopropylidene units improve thermoplasticity. Sulfone ether diamine polyamide-imide (VI) offers the best combination of high temperature performance and moldability. 相似文献
109.
Prediction of phenolic compounds in red wine fermentations by visible and near infrared spectroscopy 总被引:1,自引:0,他引:1
D Cozzolino M.J Kwiatkowski M Parker W.U Cynkar R.G Dambergs M Gishen M.J Herderich 《Analytica chimica acta》2004,513(1):73-80
Near infrared (NIR) spectroscopy was used to simultaneously predict the concentrations of malvidin-3-glucoside (M3G), pigmented polymers (PP) and tannins (T) in red wine. A total of 495 samples from 32 commercial scale red wine fermentations over two vintages using two grape varieties (Cabernet Sauvignon and Shiraz), and also including as additional variables two types of fermenters, two different yeasts, and three fermentation temperatures were used. Samples were scanned in transmission mode (400-2500 nm) using a monochromator instrument (NIRSystems6500). Calibration equations were developed from high performance liquid chromatography (HPLC) and NIR data using partial least squares (PLS) regression with internal cross validation. Using PLS regression, very good calibration statistics (Rcal2>0.80) were obtained for the prediction of M3G, PP and T with standard deviation (S.D.)/standard error in cross validation (SECV) ratio (residual predictive deviation, RPD)) ranging from 1.8 to 5.8. It was concluded that near infrared spectroscopy could be used as rapid alternative method for the prediction of the concentration of phenolic compounds in red wine fermentations. 相似文献
110.
The PCILO method is used to calculate the stabilization energies of the anionic forms of uracil by water molecules forming the first hydration shell of the tautomers. The results show that the 1-HU– tautomer is more stabilized by the solvent effect than the 3-HU– tautomer by about 8 kcal/mole. The effect brings closer together the energies of the two tautomers which differ intrinsically by about 13 kcal/mole in favour of the 3-HU– form. It operates in the direction inferred from experimental studies.This work was supported in part by R.C.P. 173 of the Centre National de la Recherche Scientifique of France and in part by the Polish Academy of Sciences within the project 09.3.1. 相似文献