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排序方式: 共有344条查询结果,搜索用时 15 毫秒
1.
The hardy-littlewood maximal function of a sobolev function 总被引:6,自引:0,他引:6
Juha Kinnunen 《Israel Journal of Mathematics》1997,100(1):117-124
We prove that the Hardy-Littlewood maximal operator is bounded in the Sobolev spaceW
1,p
(R
n
) for 1<p≤∞. As an application we study a weak type inequality for the Sobolev capacity. We also prove that the Hardy-Littlewood maximal
function of a Sobolev function is quasi-continuous. 相似文献
2.
A. Bartnik H. Fiedorowicz R. Jarocki L. Juha J. Kostecki R. Rakowski M. Szczurek 《Applied physics. B, Lasers and optics》2006,82(4):529-532
The first results of experiments on direct photo-etching of heated PTFE using a 10 Hz X-ray source based on a laser-irradiated gas puff target are presented. X-ray radiation in the wavelength range from 6 to 20 nm was produced as a result of irradiation of a double-stream gas puff target with Nd:YAG laser pulses of energy 0.8 J and time duration 3 ns. The resulting X-ray pulses with energy of about 100–200 mJ were used to irradiate samples of PTFE to create microstructures by direct photo-etching. Strong enhancement of the photo-etching process was observed for samples heated up to 300 °C. PACS 52.38.Ph; 81.65.Cf; 61.82.Pv 相似文献
3.
The effect of the heat treatment on as-spun fibers made of a commercial liquid crystalline polymer, Vectra®, was examined through tensile properties and differential scanning calorimetry (DSC) measurements. The heat treatment increased the fiber strength considerably, and it also increased the elongation at break. On the other hand, the treatment had a weaker effect on the modulus. In general, the effects of treatment depended on the temperature and on the treatment time used. DSC measurements showed the effect of the treatment on the behavior of the melting endotherm. In light of the development of this endotherm, it seems possible that the structure formed during treatment depends essentially on the treatment temperature. On the whole, an unambiguous correlation between tensile properties and calorimetric quantities could not be concluded. 相似文献
4.
Nurminen TA Holopainen JM Zhao H Kinnunen PK 《Journal of the American Chemical Society》2002,124(41):12129-12134
Sphingomyelinase, SMase (EC 3.1.4.12), was coupled onto amino-derivatized acrylate microspheres and was shown to retain its catalytic activity. The immobilized enzyme allows one to carry out topical enzymatic reaction in a controlled manner. Accordingly, these spheres were held with a micropipet and using micromanipulator brought into contact with a giant liposome membrane composed of phosphatidylcholine and sphingomyelin (SOPC/C16:0-SM, 0.75:0.25, molar ratio), representing the substrate for the immobilized enzyme. The macroscopic consequences of the enzyme reaction were visualized using fluorescence microscopy as well as differential interference contrast microscopy. The surface contact of the giant vesicle and immobilized enzyme causes membrane microdomain formation and domain clustering (capping) in the membrane and subsequent shedding of small vesicles from the membrane into the interior of the giant liposome. The method described represents a novel approach to study enzymatic reactions and allows manipulating giant vesicles as well as cultured cells in a spatially controlled manner. 相似文献
5.
Mikko Keränen Marcin Gnyba Paavo Raerinne Terho Kololuoma Arto Maaninen Juha T. Rantala 《Journal of Sol-Gel Science and Technology》2004,31(1-3):369-372
Sol–gel adhesive material for isostatic hotpressing lamination process was synthesized using 3-aminopropyltrimethoxysilane (APTES), 3-glycidyloxypropyltrimethoxysilane (GPTS) and methacryloxypropyltrimethoxysilane (MPTS) as precursors. Reaction dynamics between APTES and GPTS was followed on-line with Raman spectroscopy. The lamination process was optimized by varying hotpressing times and pressures at the constant temperature. Mechanical shear strength properties were found to be excellent for studied composition, 25–30 kg/cm2 at its best. One possible application of laminated polycarbonate (PC) structure is a soldier helmet visor. Therefore, the ballistic protection properties were tested by shooting with 1.1 gram standard fragment, and determining the v50 velocity value, which corresponds to 50% perforation. The laminated structure gave 5.7% better protection compared with the solid polycarbonate. The laminated components were found to have high optical transparency at the visible wavelengths as well as high environmental stability. 相似文献
6.
Summary Translational symmetry has been shown to be useful in the calculation of electronic structures of large lattice models. The number of unique integrals has been derived for cases of different dimensionality. For the unique integrals zero screening and approximation methods are described. The method has been applied to arrays of hydrogen atoms and to a zincblende surface model. When the size of the system is increased the translationally unique integrals are shown to become either zero or they can be calculated by simple coulombic approximations. 相似文献
7.
Two different methods to graft silica particles with poly(acrylic acid) (PAA) were studied. In the first method PAA was reacted with 1,1′‐carbonyldiimidazole to give functionalized PAA. The resulting activated carbonyl group reacted easily with 3‐aminopropyl‐functionalized silica at low temperatures. In the second method 3‐glycidoxypropyl‐functionalized silica particles were reacted directly with PAA by using magnesium chloride as a catalyst. Different molecular weights of PAAs were used in order to investigate the effect of molecular weight on grafting yields in both methods. The grafting yields were determined with thermogravimetric analysis (TGA). All products were also investigated with IR. The results showed that the yields of reactions performed at ambient temperature by using 1,1′‐carbonyldiimidazole‐functionalized PAA were the same as with a direct reaction of unfunctionalized PAA and 3‐aminopropyl‐functionalized silica performed at 153°C. Also in reactions between 3‐glycidoxypropyl‐functionalized silica and PAA the yields were satisfactory. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
8.
Let: E M be a fiber bundle and let be an infinitesimal Lie transformation group acting onE. We announce various new results concerning the cohomology of the invariant variational bicomplex (
*,*
(J(E)), dH, dV) and the associated invariant Euler-Lagrange complex. As one application of our general theory, we completely solve the local invariant inverse problem of the calculus of variations for finite-dimensional infinitesimal Lie transformation groups. 相似文献
9.
Juha Vuolle-Apiala 《Journal of Theoretical Probability》1996,9(4):853-861
We consider a class of possible extensions of a given symmetric Feller processZ
t
fromR{0} to the entire real lineR, depending on a parameter [0, 1]. It is proved that the proposed extension exists if =1/2; for 1/2, exists if and only ifZ
t
does not jump over 0 (e.g., ifZ
t
is a diffusion). 相似文献
10.
Summary A simple and specific HPLC method with coulometric detection was developed for the determination of 2′-acetyl erythromycin
and erythromycin in human plasma. Methyl tert-butyl ether was used as the extraction solvent after alkalization of plasma
samples. The plasma extracts were chromatographed on a reverse phase column using 4-component mobile phase. The manual sample
preparation procedure was modified so that it could also be applied to the robotic system (Zymate™ Laboratory Automation System). The linear range was 0.25–7.0 μg/ml. The quantitation limit for 2′-acetyl erythromycin and
erythromycin was 0.05 μg/ml. Equivalent manual and robotic sample preparation methods were used to analyze a large number
of plasma samples. 相似文献