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961.
Kai Wei Tomohiro Ohta Byoung‐Suhk Kim Kwan‐Woo Kim Keun‐Hyung Lee Myung Seob Khil Hak‐Yong Kim Ick‐Soo Kim 《先进技术聚合物》2010,21(10):746-751
The metallized hybrid nanofiber webs were prepared by using a combined technology of electrostatic spinning and metallization. The electrospun polyurethane (PU) nanofibers were metallized with different thicknesses of copper layer via metal vapor deposition technique. The thickness of the copper layer, which ranges from 10 to 100 nm, was monitored and controlled. The resultant metallized hybrid nanofiber webs were characterized using field emission scanning electron microscopy (FE‐SEM), wide angle X‐ray diffraction (WAXD), and thermogravimetric analysis (TGA). FE‐SEM images demonstrated that the nanoscaled copper layers are well deposited on the surface of the PU nanofibers. TGA result indicated that the thermal stability of the metallized hybrid PU nanofibers was dramatically enhanced due to the barrier effects of thin metallic copper layer. WAXD data confirmed that the crystalline copper layers were well deposited onto the PU nanofibers. Moreover, the mechanical properties of the metallized hybrid PU nanofiber webs were increased with increase in the thickness of deposited copper layer. Unlike the organic PU nanofiber webs, it was observed that the metallized hybrid PU nanofiber webs showed higher conductive properties depending on the thickness of the deposited copper layer. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
962.
Presence of inhomogeneous layered structures of ionic liquid (IL) molecules at IL/HOPG and IL/mica interfaces was directly detected and imaged by using frequency-modulation atomic force microscopy. High stability of the layered structures may disturb their interface applications to catalysis and electrochemistry. 相似文献
963.
Yamada K Sato T Hosoi M Yamamoto Y Tomioka K 《Chemical & pharmaceutical bulletin》2010,58(11):1511-1516
Stereoselective formal synthesis of (+)-allokainic acid was accomplished starting from L-glutamate by using a thiol-mediated acyl radical cyclization as a key step. The cyclization of a formylalkenoate proceeded in a highly diastereoselective manner to give trans-4,5-disubstituted pyrrolidin-3-one without the production of the cis-isomer. The pyrrolidinone was then converted into the established synthetic intermediate of (+)-allokainic acid via the iron-catalyzed coupling reaction with an isopropenyl Grignard reagent. 相似文献
964.
Michito Shiotsuka Housei Koumura Yasushi Suwaki Masahiro Asai Hitoshi Tatemitsu Tomohiro Ozawa Hideki Masuda 《Transition Metal Chemistry》2009,34(3):353-359
Two dinuclear complexes with novel coordination type, [Cu2(DPDIDT)2](PF6)2 (1) and [Ag2(DPDIDT)2](BF4)2 (2), plus a dinuclear complex of the usual coordination type, {Re(Cl)(CO)3}2(DPDIDT) (3) as a comparative complex were prepared from bis-(4-(2-pyridylmethyleneiminophenyl))disulfide (DPDIDT) and the relevant metal
sources. Complexes (1) and (2) exist in solution as dimer structures of the square-pole type according to the interpretation of the ESI mass and 1H NMR spectra. The density functional theory calculations for the monomer and dimer models of the Cu(I) complex cations, [Cun(DPDIDT)n]n+ (n = 1, 2), demonstrated that the dimer form is structurally more stable than the monomer form. The UV–Vis absorption spectra
of complexes (1) and (3) both exhibit a typical MLCT absorption band in the 400–700 nm region. The Re(I) complex (3) was revealed to possess a facial configuration with respect to the three carbonyl ligands by 1H NMR and IR data. 相似文献
965.
Inositol and their derivatives are important class of biologically active natural products. Among the nine theoretically possible inositols, six are known to occur in nature. Interestingly one or more methyl ethers of these inositols have been isolated from plants and these methyl inositols are presumed to have important functions in plant biology. Brahol and pinpollitol are two naturally occurring methylated inositols reported to have allo-inositol and chiro-inositol configurations, respectively. Adopting our sulfonate inversion strategies for synthesizing protected chiro- and allo-inositols from cheaply available myo-inositol in combination with new methods we have achieved the total syntheses of these methylated inositols. The proposed structure of brahol has been synthesized in six steps from myo-inositol. We have not only disproved the proposed structure of brahol but also established its correct structure. Also, we have efficiently synthesized pinpollitol and its positional isomer from myo-inositol. These works involve several selective protection-deprotection strategies of inositol hydroxyl groups. 相似文献
966.
We consider the asymmetric simple exclusion process in one dimension with weak asymmetry (WASEP) and 0–1 step initial condition. Our interest are the fluctuations of the time-integrated particle current at some prescribed spatial location. One expects a crossover from Gaussian to Tracy-Widom distributed fluctuations. The appropriate crossover scale is an asymmetry of order \(\sqrt{\varepsilon}\), times of order ε ?2, and a spatial location of order ε ?3/2. For this parameter window we obtain the limiting distribution function of the integrated current in terms of an integral over the difference of two Fredholm determinants. For large times, on the scale ε ?2, this distribution function converges to the one of Tracy-Widom. 相似文献
967.
Tomohiro Uchiyama 《代数通讯》2018,46(3):1333-1343
Let k be a nonperfect separably closed field. Let G be a connected reductive algebraic group defined over k. We study rationality problems for Serre’s notion of complete reducibility of subgroups of G. In particular, we present a new example of subgroup H of G of type D4 in characteristic 2 such that H is G-completely reducible but not G-completely reducible over k (or vice versa). This is new: all known such examples are for G of exceptional type. We also find a new counterexample for Külshammer’s question on representations of finite groups for G of type D4. A problem concerning the number of conjugacy classes is also considered. The notion of nonseparable subgroups plays a crucial role in all our constructions. 相似文献
968.
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970.
Thermodynamics for the Formation of Double‐Stranded DNA–Single‐Walled Carbon Nanotube Hybrids 下载免费PDF全文
Prof. Tomohiro Shiraki Akiko Tsuzuki Dr. Fumiyuki Toshimitsu Prof. Naotoshi Nakashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(14):4774-4779
For the first time, the thermodynamics are described for the formation of double‐stranded DNA (ds‐DNA)–single‐walled carbon nanotube (SWNT) hybrids. This treatment is applied to the exchange reaction of sodium cholate (SC) molecules on SWNTs and the ds‐DNAs d(A)20–d(T)20 and nuclear factor (NF)‐κB decoy. UV/Vis/near‐IR spectroscopy with temperature variations was used for analyzing the exchange reaction on the SWNTs with four different chiralities: (n,m)=(8,3), (6,5), (7,5), and (8,6). Single‐stranded DNAs (ss‐DNAs), including d(A)20 and d(T)20, are also used for comparison. The d(A)20–d(T)20 shows a drastic change in its thermodynamic parameters around the melting temperature (Tm) of the DNA oligomer. No such Tm dependency was measured, owing to high Tm in the NF‐κB decoy DNA and no Tm in the ss‐DNA. 相似文献