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991.
Carla Estivill Albert Virgili Eva Monteagudo Francisco Sánchez-Ferrando Juan F. Piniella 《Tetrahedron》2009,65(1):171-8937
A new chiral diamine with low basicity was synthesized in enantiopure form. (1R,1′R)-1,1′-(Anthracene-9,10-diyl)bis(2,2,2-trifluoroethanamine) was obtained by means of several stereochemically controlled reactions. The structures of the title compound and several intermediates were studied. 相似文献
992.
This study demonstrates the surface modification of thermally expandable core/shell microspheres by grafting glycidyl methacrylate (GMA) using activators regenerated by electron transfer (ARGET) ATRP. To retain the expansion properties it was essential to minimize the shear forces, use solvents compatible with the microspheres and keep the reaction times short (three hours or less). Using microspheres with hydroxyl groups on the surface, it was found that after converting these to α-bromo esters, GMA could be grafted by ARGET ATRP using only 50 ppm of copper catalyst in toluene at 30 °C. Decent control of the polymerization was achieved with PMDETA as ligand reaching PDIs of 1.4 for the solution polymerization of GMA. When microspheres were present, the polymerization was less controlled with higher PDIs. The epoxide groups of the grafted microspheres were hydrolyzed by HCl in THF providing a hydrophilic surface of the microsphere. The expansion property of the microspheres was studied after each reaction step by thermal mechanical analysis, and it was found that the expansion capacity was well preserved with only limited negative effect on the microspheres. 相似文献
993.
Jaroslav Blaško Róbert Kubinec Ivan Ostrovský Eva Pavlíková Ján Krupčík Ladislav Soják 《Journal of chromatography. A》2009,1216(14):2757-2761
A generally known problem of GC separation of trans-7;cis-9; cis-9,trans-11; and trans-8,cis-10 CLA (conjugated linoleic acid) isomers was studied by GC–MS on 100 m capillary column coated with cyanopropyl silicone phase at isothermal column temperatures in a range of 140–170 °C. The resolution of these CLA isomers obtained at given conditions was not high enough for direct quantitative analysis, but it was, however, sufficient for the determination of their peak areas by commercial deconvolution software. Resolution factors of overlapped CLA isomers determined by the separation of a model CLA mixture prepared by mixing of a commercial CLA mixture and CLA isomer fraction obtained by the HPLC semi-preparative separation of milk fatty acids methyl esters were used to validate the deconvolution procedure. Developed deconvolution procedure allowed the determination of the content of studied CLA isomers in ewes’ and cows’ milk samples, where dominant isomer cis-9,trans-11 is eluted between two small isomers trans-7,cis-9 and trans-8,cis-10 (in the ratio up to 1:100). 相似文献
994.
Phthalocyanines (Pc), which are peripherally substituted with pyridin-3-yloxy groups, have shown promise as sensitizers for photodynamic cancer therapy (PDT). Some aza-analogues (AzaPc) are reported here. Four monomers were synthesized, i.e. 5,6-di(pyridin-3-yloxy)pyrazine-2,3-dicarbonitrile, and three pyrazine-2,3-dicarbonitriles, substituted with pyridin-3-yloxy- in combination with H, Me and Ph groups. Cyclotetramerizations of these monomers with the reagent Zn(quinoline)2Cl2 yielded the targeted ZnAzaPcs in 20–40% yields.The cyclotetramerizations were accompanied, and apparently initiated, by complexation between zinc(II) and the pyridin-3-yloxy groups attached to the pyrazine-dicarbonitriles. Two such zinc(II) complexes were isolated and characterized. Identifications of all new substances were primarily based on NMR spectra, where the pulse techniques COSY, NOESY, HSQC and HMBC were applied. Molecular ions of the ZnAzaPcs were determined by mass spectrometry (MALDI-TOF). The UV–Vis spectra of these macrocycles were as expected, with Q-band absorptions at 630–650 nm and molar extinction coefficients, ε, 70 000–100 000. Eight peripheral pyridin-3-yloxy groups induced a small blue shift of the Q-band, from 636 nm for unsubstituted ZnAzaPc, to 630 nm, whereas a red shifted Q-band at 650 nm resulted from the combination of phenyl and pyridin-3-yloxy substituents. Improved solubilities were observed for the unsymmetrical ZnAzaPcs compared to octa(pyridin-3-yloxy)ZnAzaPc. 相似文献
995.
Victoria L. Blair Luca M. Carrella William Clegg Prof. Jan Klett Dr. Robert E. Mulvey Prof. Dr. Eva Rentschler Prof. Dr. Luca Russo Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(4):856-863
With the aim of introducing the diisopropylamide [NiPr2] ? ligand to alkali‐metal‐mediated manganation (AMMMn) chemistry, the temperature‐dependent reactions of a 1:1:3 mixture of butylsodium, bis(trimethylsilylmethyl)manganese(II), and diisopropylamine with ferrocene in hexane/toluene have been investigated. Performed at reflux temperature, the reaction affords the surprising, ferrocene‐free, hydrido product [Na2Mn2 (μ‐H)2{N(iPr)2}4]?2 toluene ( 1 ), the first Mn hydrido inverse crown complex. Repeating the reaction rationally, excluding ferrocene, produces 1 in an isolated crystalline yield of 62 %. At lower temperatures, the same bimetallic amide mixture leads to the manganation of ferrocene to generate the first trimanganese, trinuclear ferrocenophane, [{Fe(C5H4)2}3{Mn3Na2(NiPr2)2 (HNiPr2)2}] ( 2 ) in an isolated crystalline yield of 81 %. Both 1 and 2 have been characterised by X‐ray crystallographic studies. The magnetic properties of paramagnetic 1 and 2 have also been examined by variable‐temperature magnetisation measurements on powdered samples. For 1 , the room‐temperature value for χT is 3.45 cm3 K mol?1, and on lowering the temperature a strong antiferromagnetic coupling between the two Mn ions is observed. For 2 , the room‐temperature value for χT is 4.06 cm3 K mol?1, which is significantly lower than the expected value for three isolated paramagnetic MnII ions. 相似文献
996.
William Clegg Prof. Ben Conway David V. Graham Eva Hevia Dr. Alan R. Kennedy Dr. Robert E. Mulvey Prof. Luca Russo Dr. Dominic S. Wright Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(29):7074-7082
Two potassium–dialkyl–TMP–zincate bases [(pmdeta)K(μ‐Et)(μ‐tmp)Zn(Et)] ( 1 ) (PMDETA=N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine, TMP=2,2,6,6‐tetramethylpiperidide), and [(pmdeta)K(μ‐nBu)(μ‐tmp)Zn(nBu)] ( 2 ), have been synthesized by a simple co‐complexation procedure. Treatment of 1 with a series of substituted 4‐R‐pyridines (R=Me2N, H, Et, iPr, tBu, and Ph) gave 2‐zincated products of the general formula [{2‐Zn(Et)2‐μ‐4‐R‐C5H3N}2 ? 2{K(pmdeta)}] ( 3 – 8 , respectively) in isolated crystalline yields of 53, 16, 7, 23, 67, and 51 %, respectively; the treatment of 2 with 4‐tBu‐pyridine gave [{2‐Zn(nBu)2‐μ‐4‐tBu‐C5H3N}2 ? 2{K(pmdeta)}] ( 9 ) in an isolated crystalline yield of 58 %. Single‐crystal X‐ray crystallographic and NMR spectroscopic characterization of 3 – 9 revealed a novel structural motif consisting of a dianionic dihydroanthracene‐like tricyclic ring system with a central diazadicarbadizinca (ZnCN)2 ring, face‐capped on either side by PMDETA‐wrapped K+ cations. All the new metalated pyridine complexes share this dimeric arrangement. As determined by NMR spectroscopic investigations of the reaction filtrates, those solutions producing 3 , 7 , 8 , and 9 appear to be essentially clean reactions, in contrast to those producing 4 , 5 , and 6 , which also contain laterally zincated coproducts. In all of these metalation reactions, the potassium–zincate base acts as an amido transfer agent with a subsequent ligand‐exchange mechanism (amido replacing alkyl) inhibited by the coordinative saturation, and thus, low Lewis acidity of the 4‐coordinate Zn centers in these dimeric molecules. Studies on analogous trialkyl–zincate reagents in the absence and presence of stoichiometric or substoichiometric amounts of TMP(H) established the importance of Zn? N bonds for efficient zincation. 相似文献
997.
Teresa García-Valderrama Eva Mulero-MendigorriDaniel Revuelta-Bordoy 《European Journal of Operational Research》2009
The objective of this article is to propose a framework for analysis of the relationships between the four perspectives of the balanced scorecard (BSC) of Kaplan and Norton. To this end, several different models of efficiency have been developed, utilising data envelopment analysis (DEA). Each of the variables has been extracted from a model of the BSC for research and development (R&D) activities. A study has been carried out with 90 companies to illustrate a case of this analysis. 相似文献
998.
Eva Pellicer Aïda Varea Salvador Pané Bradley J. Nelson Enric Menéndez Marta Estrader Santiago Suriñach Maria Dolors Baró Josep Nogués Jordi Sort 《Advanced functional materials》2010,20(6):983-991
Nanocrystalline 3 µm thick Cu1–xNix (0.45 ≤ x ≤ 0.87) films are electrodeposited galvanostatically onto Cu/Ti/Si (100) substrates, from a citrate‐ and sulphate‐based bath containing sodium lauryl sulphate and saccharine as additives. The films exhibit large values of reduced Young's modulus (173 < Er < 192 GPa) and hardness (6.4 < H < 8.2 GPa), both of which can be tailored by varying the alloy composition. The outstanding mechanical properties of these metallic films can be ascribed to their nanocrystalline nature—as evidenced by X‐ray diffraction, transmission electron microscopy, and atomic force microscopy—along with the occurrence of stacking faults and the concomitant formation of intragranular nanotwins during film growth. Due to their nanocrystalline character, these films also show very low surface roughness (root mean square deviation of around 2 nm). Furthermore, tunable magnetic properties, including a transition from paramagnetic to ferromagnetic behavior, are observed when the Ni percentage is increased. This combination of properties, together with the simplicity of the fabrication method, makes this system attractive for widespread technological applications, including hard metallic coatings or magnetic micro/nano‐electromechanical devices. 相似文献
999.
Olha Hoy Bogdan Zdyrko Robert Lupitskyy Roman Sheparovych Dennis Aulich Jiafang Wang Eva Bittrich Klaus‐Jochen Eichhorn Petra Uhlmann Karsten Hinrichs Marcus Müller Manfred Stamm Sergiy Minko Igor Luzinov 《Advanced functional materials》2010,20(14):2240-2247
The ability to vary, adjust, and control hydrophobic interactions is crucial in manipulating interactions between biological objects and the surface of synthetic materials in aqueous environment. To this end a grafted polymer layer (multi‐component mixed polymer brush) is synthesized that is capable of reversibly exposing nanometer‐sized hydrophobic fragments at its hydrophilic surface and of tuning, turning on, and turning off the hydrophobic interactions. The reversible switching occurs in response to changes in the environment and alters the strength and range of attractive interactions between the layer and hydrophobic or amphiphilic probes in water. The grafted layer retains its overall hydrophilicity, while local hydrophobic forces enable the grafted layer to sense and attract the hydrophobic domains of protein molecules dissolved in the aqueous environment. The hydrophobic interactions between the material and a hydrophobic probe are investigated using atomic force microscopy measurements and a long‐range attractive and contact‐adhesive interaction between the material and the probe is observed, which is controlled by environmental conditions. Switching of the layer exterior is also confirmed via protein adsorption measurements. 相似文献
1000.