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排序方式: 共有147条查询结果,搜索用时 15 毫秒
1.
Nagaoka Y Inoue H el-Koussi N Tomioka K 《Chemical communications (Cambridge, England)》2002,(2):122-123
Upon treatment with lithium diisopropylamide achiral and chiral alpha,beta,psi,omega-unsaturated bisphosphine oxides underwent lithiation-conjugate addition tandem cyclization to afford the corresponding endo-alpha,beta-unsaturated cyclic bisphosphine oxides; sequential stereoselective reduction of the cyclized bisphosphine oxide gave the corresponding trans- and cis-bisphosphines that were successfully applicable in a catalytic asymmetric hydrogenation as chiral bisphosphine ligands. 相似文献
2.
Galal Elmanfe Hosna Benbouzid Nawal Derkaoui Mireille Privat 《Comptes Rendus Chimie》2006,9(11-12):1476
Despite its extremely weak adsorption at the water/silica interface, carbofuran can, however, induce the coadsorption of metallic salts, like, for example, lead nitrate, and thus enhance its adsorption. We quantitatively studied this phenomenon with a depletion method and under concentration conditions close to the environmental ones. Heavy metal salt was found to positively adsorb, whereas carbofuran relative adsorption is generally slightly negative. This study provides evidence that considering these facts is of paramount importance in environmental prospects. To cite this article: G. Elmanfe et al., C. R. Chimie 9 (2006). 相似文献
3.
Al-Arfaj NA 《Talanta》2004,62(2):255-263
A flow-injection (FI) methodology using (2,2′-dipyridyl) ruthenium(II) [Ru(dipy)32+] chemiluminescence (CL) was developed for the rapid and sensitive determination of metoclopramide hydrochloride. The method is based on the CL reaction of metoclopramide with Ru(dipy)32+ and KMnO4 in a sulfuric acid medium. Under the optimum conditions, a calibration graph was obtained over the concentration range 0.005-3.5 μg ml−1 with a limit of detection (S/N=2) of 1 ng ml−1. The correlation coefficient was 0.99993 (n=8) with a relative standard deviation of 0.48% for 10 determinations of 1 μg ml−1 of drug. The method was successfully applied to the determination of metoclopramide in pharmaceutical preparations and biological fluids after IP administration of 25 mg kg−1 dose to rats. The elimination half-life was 2.5±0.4 h. 相似文献
4.
A. Ait Haddou M. Berrada G. Paić 《Journal of Radioanalytical and Nuclear Chemistry》1986,102(1):159-175
The yield and average cross section for the reactions11B(p, n)11C,12C(p, )13N,13C(p, n)13N,
12
12
C(d, n)13N,14N(p, )11C,16O(p, )13N,16O(d, n)17F,16O(t, n)18F, and18O(p, n)18F have been measured in different compounds. The charged particles were created in the samples themselves either through recoil by scattering of 14 MeV neutrons off hydrogen and deuterium, or by the (n, t) reaction on6Li using thermal neutrons. The yields of reactions12C(d, n);16O(p, );16O(t, n) and18O(p, n) have been measured using proton, deuteron and triton spectra generated by 14 MeV neutrons in the reactions D(n, p)2n;6Li(n, d);7Li(n, d) and10B(n, d);7Li(n, t) and10B(n, t), respectively. 相似文献
5.
6.
B. Ameduri K. Berrada B. Boutevin R. D. Bowden 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):477-478
Abstract The synthesis of novel monodispersed telechelic diols from the radical telomerization of undecylenol with new α,ω-dithiols was investigated. These diols are semi-crystalline and exhibit a thermal stability much higher than that of commercially available polydispersed diols. 相似文献
7.
8.
Fahmy M. Asaad Nazih Latif Nawal Mishriky Ibrahim Zeid 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):17-18
Abstract In the present investigation, the authors could obtain a new series of spiranes (1) through the reaction of the high potential quinone tetrachloro-o-benzoquinone with 2-aryl-3-phenyl-3H-quinazoline-4-thiones. Thus, 2,3-diphenyl- (2a), 2-p-tolyl-3-phenyl- (2b) and 2-p-anisyl-3-phenyl- (2c)-3H-quinazoline-4-thiones react readily with tetrachloro-o-benzoquinone, in boiling toluene, to give the corresponding spiro-1,3-benzodioxole-2,4′-(3′H)-quinazolines (1a-c), respectively. 相似文献
9.
G. Krill J. Durand A. Berrada N. Hassanain M.F. Ravet 《Solid State Communications》1980,35(7):547-550
We present the results of XPS and X-ray absorption measurements performed on the amorphous Sm Au and La Sm Au compounds. The XPS Sm 3d core level spectra in these compounds reveal that at the surface (5 ? 7 Å) the samarium ions present both the Sm2+ (4f6) and Sm3+ (4f5) configurations. When the concentration in samarium decreases it is shown that the Sm2+ configuration is strongly enhanced at the surface whereas the X-ray absorption measurements indicate on the contrary that in the bulk only the Sm3+ configuration is present. Comparison is made with similar findings in pure crystalline Sm and various crystalline rare earth compounds. 相似文献
10.
Omar Alkhazragi Hang Lu Wenbo Yan Nawal Almaymoni Tae-Yong Park Yue Wang Tien Khee Ng Boon S. Ooi 《Annalen der Physik》2023,535(9):2300289
Random number generation (RNG) is needed for a myriad of applications ranging from secure communication encryption to numerical simulations to sports and games. However, generating truly random numbers can be elusive. Pseudorandom bit generation using computer algorithms provides a high random bit generation rate. Nevertheless, the reliance on predefined algorithms makes it deterministic and predictable once initial conditions are known. Relying on physical phenomena (such as measuring electrical noise or even rolling dice) can achieve a less predictable sequence of bits. Furthermore, if the physical phenomena originate from quantum effects, they can be truly random and completely unpredictable due to quantum indeterminacy. Traditionally, physical RNG is significantly slower than pseudorandom techniques. To meet the demand for high-speed RNG with perfect unpredictability, semiconductor light sources are adopted as parts of the sources of randomness, i.e., entropy sources, in quantum RNG (QRNG) systems. The high speed of their noise, the high efficiency, and the small scale of these devices make them ideal for chip-scale QRNG. Here, the applications and recent advances of QRNG are reviewed using semiconductor emitters. Finally, the performance of these emitters is compared and discuss their potential in future technologies. 相似文献