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81.
82.
This article describes cationic ring‐opening copolymerization of a bicyclic orthoester having hydroxy group (BOE‐OH) and glycidyl phenyl ether (GPE), and the volume shrinkage behavior during the copolymerization. THF soluble polyethers [poly(BOE‐OH‐co‐GPE)] were obtained by the copolymerizations at 80–180°C, while crosslinked poly(BOE‐OH‐co‐GPE) was obtained by the copolymerizations at 220–250°C. This crosslinking reaction may originate from the dehydration of methylol groups in the side chain of poly(BOE‐OH‐co‐GPE). The volume shrinkage during the cationic copolymerization reduced as the increase of the BOE‐OH feed ratio. By contrast, the volume shrinkage on the crosslinking polymerization was almost independent on the BOE‐OH feed ratio. Poly(BOE‐OH‐co‐GPE)s with higher BOE‐OH composition showed lower thermal weight loss temperature owing to the release of H2O by dehydration of methylol groups. The BOE‐OH component in the THF soluble poly(BOE‐OH‐co‐GPE)s lowered the glass transition temperature (Tg), while that in the crosslinked poly(BOE‐OH‐co‐GPE) increased the Tg probably because of the higher crosslinking density. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1356–1361, 2006 相似文献
83.
Soluble polypyrrole (PPy) samples advanced in electrical conductivity σ were chemically synthesized with dodecylbenzenesulfonate (DBS) sodium salt as a dopant, with poly(ethylene glycol) (PEG) as an additive, and with ammonium persulfate as an oxidant. The PPy–DBS–PEG samples were soluble in organic solvents (N‐methylpyrrolinone and m‐cresol). The greater the molar percentage ratio was of DBS, the greater the solubility was of synthesized PPy composites (PPy–DBS–PEG). The maximum electrical conductivity at room temperature for PPy–DBS–PEG was 1.02 S/cm, which was in fact the true conductivity of 100/10 (mol %) PPy/DBS. The chemical composition and doping level of PPy–DBS–PEG were determined by elemental analysis. The results of Fourier transform infrared spectroscopy were used for the structural characterization of PPy–DBS–PEG. The scanning electron microscopy results showed that the electrical conductivity was related to the morphology of PPy–DBS–PEG. According to thermogravimetric analysis, PPy–DBS–PEG was more thermostable than PPy–DBS. Electron spin resonance measurements showed that the polaron and bipolaron acted as charge carriers of PPy–DBS–PEG. According to the temperature dependence of the electrical conductivity, PPy–DBS–PEG was a semiconductor and followed the three‐dimensional variable‐range hopping model. The improved electrical conductivity apparently resulted from the reduction of the crosslinking and structural defects of the PPy chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1170–1175, 2005 相似文献
84.
合成C5石油树脂催化剂的研究 总被引:1,自引:0,他引:1
研制了一种酸性离子溶液,它是一种新型的催化剂溶液,可广泛应用于均相催化.使用这种催化剂离子溶液催化合成C5石油树脂,研究了催化剂用量、温度和添加方式对聚合反应的影响. 相似文献
85.
Peter?S.?Piispanen Marcus?Persson Per?Claesson Torbj?rn?NorinEmail author 《Journal of surfactants and detergents》2004,7(2):147-159
Several novel and some previously known, mostly sugar-based, surfactants have been synthesized and some of their surface properties
have been characterized and compared with those of commercial nonylphenol ethoxylates. The surfactant solubility in water,
ethanol, and dodecane was studied. The properties of these compounds as emulsification agents in systems composed of the surfactant
with water/isopropyl myristate, water/rapeseed oil, and water/dodecane are presented. The aqueous solubility of the surfactants
follows the general trend expected from their hydrophilic-lipophilic balance according to Griffin (HLBG), but it is also clear
that the nature of the headgroup and the structure of the nonpolar part affect the solubility in a manner not aptured in the
standard HLBG concept. An ester or amine group as the connecting unit between the hydrophile and the hydrophobe produces a
more water-soluble surfactant than the corresponding amide derivative. Some effective emulsifiers were found. For instance,
the surfactants with a dehydroabietic nonpolar group appear to be promosing emulsifiers. Most sugar-based surfactants were
able to form macroemulsions of up to around 2 wt/vol% of oil. The stability of many of these amulsions was very high, extending
for months. 相似文献
86.
Foams used in buoyancy applications must resist penetration by water at significant depths of immersion. The behavior of water blown rigid polyurethane foam at different water pressures from 0 to 3 MPa are studied in this work. The effects of different surfactants on the cell structure and hydraulic resistance of the foams are examined. The foams have densities in the range of 145 to 160 kg/m3. With increasing applied hydraulic pressure, it is found that the foams have very small buoyancy losses at low pressures but beyond a threshold pressure, buoyancy losses increase rapidly. The threshold pressures of the foams increase with decrease in cell window area. A cell window is the lamella of the foam material that separates two adjacent cells. The cell sizes of the foam are found to correlate with the size of the air bubbles entrained during initial mixing. Surfactants, which reduce the surface tension of the polyol to the greatest extent, are found to give the finest initial bubbles, smaller cells, and foams with the highest hydraulic resistance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2821–2829, 2004 相似文献
87.
88.
提出了喷射载冷剂HCFC123动态制冰的基本原理和制取冰浆的方法,分析了乙二醇、Tween-80、十二烷基硫酸钠及十二烷基硫酸钠+丙三醇复配溶液等4种添加剂在制取冰浆过程中的特点,以冰浆的流动性、含冰率(IPF)、HCHFC123能否从冰浆和含添加剂的溶液中析出作为判断依据,找到了十二烷基硫酸钠和丙三醇复配溶液是制取冰浆的最佳添加剂。 相似文献
89.
Formulating middle-phase microemulsions using mixed anionic and cationic surfactant systems 总被引:1,自引:0,他引:1
T.?Doan E.?Acosta J.?F.?Scamehorn D.?A.?SabatiniEmail author 《Journal of surfactants and detergents》2003,6(3):215-224
Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid
crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby
allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role
of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied
for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane,
and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed
us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form).
The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1∶1 for univalent surfactants
as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic
surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the
oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed
very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The
results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient
for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures
advantageous. 相似文献
90.
Hyun‐Ah Kang Gyu‐Jong Jeon Moo‐Yeal Lee Ji‐Won Yang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(2):205-210
A series of alginate‐derived polymeric surfactants (APSs) with a linear alkyl group (C8, C12, C16) was synthesized by oxidation followed by reductive amination of 2,3‐dialdehydic alginate. The products were characterized by measuring IR spectra, NMR spectra, surface tension and critical micelle concentration (cmc). They were also tested for the solubilization of azobenzene and adsorption of heavy metal. In the case of 40% CHO‐C8 APSs, the lowest interfacial tension value (31.5 m Nm?1) was obtained at the cmc value of 1.35 g dm?3. The dissolving capacity of 40% CHO‐C8 APS towards azobenzene was 27 times greater than that of alginate. The overall cobalt (Co2+) removal efficiency by adsorption using APSs was high compared with that of sodium alginate at pH 3, 5 and 7. Equilibrium aspects of cobalt adsorption onto 10% CHO‐APSs were studied, and the results show that APSs had high equilibrium capacities for cobalt uptake, 115.5 mgg?1. © 2002 Society of Chemical Industry 相似文献