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111.
Qian Yang Hao Jin Yiding Xu Zhihao Shen Xinghe Fan Dechun Zou Qifeng Zhou 《Journal of polymer science. Part A, Polymer chemistry》2010,48(24):5670-5678
Block copolymers containing thiophene units in one block and oxadiazole (OXD) units in the other were prepared. Atom transfer radical polymerization method was used to obtain the thiophene‐containing mesogen‐jacketed polymers, and the kinetic study indicated that the polymerization was controllable and the polymers could be used to initiate the polymerization of the OXD‐containing monomers. Photoluminescent spectra indicated that the fluorescence quantum yields of the polymers increased with increasing content of OXD. And, more OXD domains, that is, more interfaces between the hole‐transport parts and electron‐transport parts, resulting in the higher probability of exciplex formation. The electroluminescent devices containing the block copolymer with 64 mol % OXD as the emissive layer had a maximum brightness of 127 cd/m2 and an extremely low onset voltage of 7.7 V, which indicated that the injection and transport of charge carriers were facilitated and the number of charge carriers was sufficiently high in early time after the voltage was turned on. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
112.
William M. Yen 《Physics of the Solid State》1999,41(5):693-696
In this paper we shall review techniques for the growth of single crystal, mostly of insulating material, which are shaped
during the growth process. In particular, we shall focus on the growth of single-crystal fibers of optically activated materials;
the emphasis will be placed on the so-called Laser Heated Pedestal Growth (LHPG) method of pulling crystalline fibers. LHPG
offers a number of logistical advantages which can be exploited as a tool for materials research. Progress in the synthesis
of materials using LHPG is described, as are spectroscopic techniques which are employed in characterizing the optical and
physical properties of the crystal fibers obtained by this method.
Fiz. Tverd. Tela (St. Petersburg) 41, 770–773 (May 1999)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
113.
In this paper we establish some implicit function theorems for a class of locally Lipschitz set-valued maps and then apply them to investigate some questions concerning the stability of optimization problems with inclusion constraints. In consequence we have an extension of some of the corresponding results of Robinson, Aubin, and others. 相似文献
114.
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116.
Hung‐Ju Yen Guey‐Sheng Liou 《Journal of polymer science. Part A, Polymer chemistry》2009,47(6):1584-1594
Two novel poly(amine‐hydrazide)s were prepared from the polycondensation reactions of the dicarboxylic acid, 9‐[N,N‐di(4‐carboxyphenyl)amino]anthracene ( 1 ), with terephthalic dihydrazide ( TPH ) and isophthalic dihydrazide ( IPH ) via the Yamazaki phosphorylation reaction, respectively. The poly(amine‐hydrazide)s were readily soluble in many common organic solvents and could be solution cast into transparent films. Differential scanning calorimetry (DSC) indicated that these hydrazide polymers had glass‐transition temperatures (Tg) in the range of 182–230 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300–400 °C. The resulting poly(amine‐1,3,4‐oxadiazole)s had useful levels of thermal stability associated with high Tg (263–318 °C), 10% weight‐loss temperatures in excess of 500 °C, and char yield at 800 °C in nitrogen higher than 55%. These organo‐soluble anthrylamine‐based poly(amine‐hydrazide)s and poly (amine‐1,3,4‐oxadiazole)s exhibited maximum UV‐vis absorption at 346–349 and 379–388 nm in N‐methyl‐2‐pyrrolidone (NMP) solution, respectively. Their photoluminescence spectra in NMP solution showed maximum bands around 490–497 nm in the green region. The poly(amine‐hydrazide) I ‐ IPH showed a green photoluminescence at 490 nm with PL quantum yield of 29.9% and 17.0% in NMP solution and film state, respectively. The anthrylamine‐based poly(amine‐1,3,4‐oxadiazole)s revealed a electrochromic characteristics with changing color from the pale yellow neutral form to the red reduced form when scanning potentials negatively from 0.00 to ?2.20 V. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1584–1594, 2009 相似文献
117.
Xinde Tang Xiaochao Liang Qian Yang Xinghe Fan Zhihao Shen Qifeng Zhou 《Journal of polymer science. Part A, Polymer chemistry》2009,47(17):4420-4427
Novel AB2‐type amphiphilic block copolymers of poly(ethylene glycol) and poly(N‐isopropylacrylamide), PEG‐b‐(PNIPAM)2, were successfully synthesized through single‐electron transfer living radical polymerization (SET‐LRP). A difunctional macroinitiator was prepared by esterification of 2,2‐dichloroacetyl chloride with poly(ethylene glycol) monomethyl ether (PEG). The copolymers were obtained via the SET‐LRP of N‐isopropylacrylamide (NIPAM) with CuCl/tris(2‐(dimethylamino)ethyl)amine (Me6TREN) as catalytic system and DMF/H2O (v/v = 3:1) mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography and 1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions (PDI < 1.15). Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry. As a result, the phase transition temperature of PEG44‐b‐(PNIPAM55)2 is similar to that in the case of PEG44‐b‐PNIPAM110; however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular architecture on the phase transition. This is the first study into the effect of macromolecular architecture on the phase transition using AB2‐type amphiphilic block copolymer composed of PEG and PNIPAM. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4420–4427, 2009 相似文献
118.
We study the contractibility of the efficient solution set of strictly quasiconcave vector maximization problems on (possibly) noncompact feasible domains. It is proved that the efficient solution set is contractible if at least one of the objective functions is strongly quasiconcave and any intersection of level sets of the objective functions is a compact (possibly empty) set. This theorem generalizes the main result of Benoist (Ref.1), which was established for problems on compact feasible domains.The authors thank Dr. T. D. Phuong, Dr. T. X. D. Ha, and the referees for helpful comments and suggestions. 相似文献
119.
Chia‐Fen Lee Chia‐Jen Wen Chia‐Lung Lin Wen‐Yen Chiu 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):3029-3037
Poly [N‐isopropylacrylamide (NIPAAm)–chitosan] crosslinked copolymer particles were synthesized by soapless emulsion copolymerization of NIPAAm and chitosan. An anionic initiator [ammonium persulfate (APS)] and a cationic initiator [2,2′‐azobis(2‐methylpropionamidine)dihydrochloride (AIBA)] were used to initiate the reaction of copolymerization. The chitosan–NIPAAm copolymer synthesized by using APS as the initiator showed a homogeneous morphology and exhibited the characteristic of a lower critical solution temperature (LCST). The copolymer synthesized by using AIBA as an initiator showed a core–shell morphology, and the characteristic of LCST was insignificant. The LCST of the chitosan–NIPAAm copolymer depended on the morphology of the copolymer particles. In addition, the chitosan–NIPAAm copolymer particles were processed to form copolymer disks. Then, the effect of various variables such as the chitosan/NIPAAm weight ratio, the concentration of crosslinking agent, and the pH values on the swelling ratio of chitosan–NIPAAm copolymer disks were investigated. Furthermore, caffeine was used as the model drug to study the characteristics of drug loading of the chitosan–NIPAAm copolymer disks. Variables such as the chitosan/NIPAAm weight ratio and the concentration of the crosslinking agent significantly influenced the behavior of caffeine loading. Two factors (pore size and swelling ratio) affected the behavior of caffeine release from the chitosan–NIPAAm copolymer disks. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3029–3037, 2004 相似文献
120.
对1.5μm波导型声光TE-TM模式转换光滤波器进行了研究。采用了可降低驱动功率的表面声波导结构。在1.5 ̄1.6μm波段实现了可调滤光,通带宽度小于2nm,达到97¥以上转换率所需的射频驱动功率约80mW(19dBm),器件总插入损耗约9dB。 相似文献