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111.
The uniform-approximation approach is an a-priori assumption free structured approach for the derivation of hierarchies of lower-dimensional theories for thin structures with increasing approximation accuracy. In this publication, we derive a second-order consistent plate theory for monoclinic material and investigate several theories that arise from the original theory by a pseudo-reduction approach which aims to reduce the number of PDEs that are to solve. A one-variable model that governs only the interior solution is presented and, in addition, an extended two-variable model that also covers edge effects. Since the second introduced variable is a rotation of a vector field, we have to uniquely identify the rotation dependent parts in general gradients of the vector field, which is resolved by the introduction of an orthogonal decomposition. The final two-variable model is equivalent to the Reissner–Mindlin theory for the special case of isotropic material, whereas the one-variable model is equivalent to the first Reissner PDE. In contrast to this special case, the two-variable model is a coupled system of two PDEs for general monoclinic material. 相似文献
112.
The profile of fructooligosaccharides and fructopolysaccharides in artichoke heads and dandelion roots was investigated. For this purpose, a suitable method for high-performance anion exchange chromatography with pulsed amperometic detection was developed. The separation of monomers, oligomers and polymers up to a chain length of 79 sugar residues was achieved in one single run. Glucose, fructose, sucrose and individual fructooligosaccharides (kestose, nystose, fructofuranosylnystose) were quantified in six different artichoke cultivars and in dandelion roots. The contents ranged from 12.9 g/kg DM to 71.7 g/kg DM for glucose, from 15.8 g/kg DM to 67.2 g/kg DM for fructose, and from 16.8 g/kg DM to 55.2 g/kg DM for sucrose in the artichoke heads. Kestose was the predominant fructooligosaccharide, followed by nystose and fructofuranosylnystose. In four cultivars fructofuranosylnystose was only detectable in traces and reached its maximum value of 3.6 g/kg DM in the cultivar Le Castel. Furthermore, an average degree of polymerization of 5.3 to 16.7 was calculated for the individual artichoke cultivars, which is noticeably lower than hitherto reported. In contrast, the contents of kestose, nystose and fructofuranosylnystose in dandelion root exceeded that of artichoke, reflecting the short chain characteristic of the inulin, which was confirmed by chromatographic analysis. 相似文献
113.
114.
Theis B Weiss J Lippert WP Bertermann R Burschka C Tacke R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(8):2202-2206
Two nutrients in one molecule: A zwitterionic λ(5)Si,λ(5)Si'-disilicate (1) was synthesized and characterized. It contains ligands that exclusively derive from natural products ((R,R)-tartaric acid, choline). Hydrolysis of 1 yields 2, which shows a remarkable kinetic stability in water. Upon dissolution of 1 and 2 in water, the nutrients choline and orthosilicic acid are formed by hydrolysis. 相似文献
115.
Maria Buchweitz Gennadi Gudi Reinhold Carle Dietmar R. Kammerer Hartwig Schulz 《Journal of Raman spectroscopy : JRS》2012,43(12):2001-2007
The FT‐Raman spectra of the chloride salts of pelargonidin‐3‐glucoside, cyanidin‐3‐glucoside and delphinidin‐3‐glucoside, their structures at pH 5.0 and their interaction with aluminium and ferric ions are presented for the first time and discussed with regard to their spectroscopic response. Two marker bands at approximately 1510 and 1330/1350 cm−1 and one band at approximately 1330/1350 cm−1 were identified being characteristic for the formation of ferric and aluminium chelates, respectively, of cyanidin‐3‐glucoside and delphinidin‐3‐glucoside. In contrast, pelargonidin‐3‐glucoside, exhibiting one single hydroxyl group in the B‐ring, did not form metal chelates, which could be clearly demonstrated by missing marker bands. The formation of anthocyanin–metal chelates was also verified in model systems containing commercial sugar beet pectin and a pectic polysaccharide fraction isolated thereof, respectively. In addition, the absence of anthocyanin–metal chelates in systems prepared with citrate buffer was confirmed, and the effects of low and high methoxylated citrus pectins on chelate formation were studied. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
116.
Mike Espig Wolfgang Hackbusch Thorsten Rohwedder Reinhold Schneider 《Numerische Mathematik》2012,122(3):469-488
In this article we introduce a calculus of variations for sums of elementary tensors and apply it to functionals of practical interest. The survey provides all necessary ingredients for applying minimization methods in a general setting. The important cases of target functionals which are linear and quadratic with respect to the tensor product are discussed, and combinations of these functionals are presented in detail. As an example, we consider the solution of a linear system in structured tensor format. Moreover, we discuss the solution of an eigenvalue problem with sums of elementary tensors. This example can be viewed as a prototype of a constrained minimization problem. For the numerical treatment, we suggest a method which has the same order of complexity as the popular alternating least square algorithm and demonstrate the rate of convergence in numerical tests. 相似文献
117.
118.
Tomas Fritioff Conny Carlberg Guilhem Douysset Reinhold Schuch Ingmar Bergström 《Hyperfine Interactions》2001,132(1-4):229-242
The Penning trap mass spectrometer SMILETRAP has been considerably improved during the last two years. The helium pressure
has been carefully stabilized and is now independent of irregular air pressure. The temperature of the hyperboloidal precision
trap is stabilized to ±0.03°C. Remaining temperature instabilities are compensated by changes in the current of a warm coil
surrounding the precision trap. The frequency synthesizer is now locked to GPS. This means that it is much easier to accurately
measure resonances during several days. The improvements have demonstrated that in mass doublet measurements with an excitation
time of 1 s it is possible to determine the mass of ions with q/A=1/2 at an uncertainty to a few times of 0.1 ppb, using selected rather than cooled ions. In routine measurements lasting
for one day it is possible to reach a mass uncertainty of 1 ppb. The masses of the following particles and atoms have been
measured with uncertainties in the region 0.3–2 ppb: p, 3H, 3He, 4He, 22Ne, 28Si, 36Ar, 76Ge, 76Se, 86Kr and 133Cs. It has also been shown that though we are using a warm bore the trap pressure is sufficiently low to prevent electron
capture from the rest gas for excitation times of 3 s and for ion charges as high as 50+.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
119.
For any quasiordered set (`quoset') or topological space S, the set Sub
S of all nonempty subquosets or subspaces is quasiordered by embeddability. Given any cardinal number n, denote by p
n
and q
n
the smallest size of spaces S such that each poset, respectively, quoset with n points is embeddable in Sub
S. For finite n, we prove the inequalities n + 1 ≤p
n
≤q
n
≤p
n
+ l(n) + l(l(n)), where l(n) = min{k∈ℕ∣n≤2
k
}. For the smallest size b
n
of spaces S so that Sub
S contains a principal filter isomorphic to the power set ?(n), we show n + l(n) − 1 ≤b
n
≤n + l(n) + l(l(n))+2. Since p
n
≤b
n
, we thus improve recent results of McCluskey and McMaster who obtained p
n
≤n
2. For infinite n, we obtain the equation b
n
= p
n
= q
n
= n.
Received: April 19, 1999 Final version received: February 21, 2000 相似文献
120.