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991.
Neung‐Ju Lee Ja‐Chul Koo Sung‐Suk Ju Seong‐Bae Moon Won‐Jei Cho In‐Cheol Jeong Song‐Jae Lee Moo‐Youn Cho Emmanuel A Theodorakis 《Polymer International》2002,51(7):569-576
The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: Mn = 8900 g mol?1, Mw = 13 300 g mol?1, Mw/Mn = 1.5 for poly(ETPFU); Mn = 13 500 g mol?1, Mw = 16 600 g mol?1, Mw/Mn = 1.2 for poly(ETPFU‐co‐AA); Mn = 8300 g mol?1, Mw = 11 600 g mol?1, Mw/Mn = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg?1). © 2002 Society of Chemical Industry 相似文献
992.
枸杞黑果病是枸杞产区的主要病害.发病后造成黑花、黑蕾和黑果,使枸杞产量降低,品质变劣。为探明四种杀菌剂对枸杞黑果病的防治效果及最佳剂量,2003年对下述四种杀菌剂进行了田间药效对比试验,调查防效结果如下:20%三苯基醋酸锡WP450~281g/hm^2(以有效成分计,下同),20%氟硅唑EC21.08g/hm^21.5%噻霉酮EW16、88~21.08g/hm^2、40%氟硅唑EC450g/hm^2和70%甲基托布津WP787.5g/hm^2对枸杞黑果病防效均在88.25%以上。经LSD检验各处理间防效无显著差异。 相似文献
993.
M. S. Hedenqvist J. E. Ritums M. Cond‐Brana G. Bergman 《Polymer Engineering and Science》2004,44(1):113-122
The transport of water, hydrochloric acid, hydrobromic acid and tetrachloroethylene in an poly(ethylene‐co‐chlorotrifluoroethylene) and polyvinylidene fluoride were studied at 70°C by the sorption/desorption technique. The effects on the structure and mechanical properties were studied using size‐exclusion chromatography, infrared spectroscopy, differential scanning calorimetry and tensile testing. Solute concentrations in the polymers indicated that both the water and HCl/HBr components diffused into the polymers on exposure to acid solutions. The calculated water contents of the diffusing acids generally differed from the water content in the solution. The ratio of water content in the diffusing acid to that in the surrounding acid solution was generally a function of the relative vapor activity of water and HCl/HBr. It was possible to describe the 35%HCl and 47%HBr desorption data using a two component model. It was here assumed that the water and HCl/HBr diffused separately, each having its own constant diffusion coefficient. The water diffusivity was obtained from the pure water system, and this allowed the HCl/HBr diffusivity to be calculated. It was found that the diffusivity decreased, in a non‐simple way, as a function of solute size. The exposure to solute did not lower the molar mass of the polyvinylidene fluoride. Differential scanning calorimetry indicated the development of low‐melting point polyvinylidene fluoride crystals during the exposure to all solutes. This seemed to be a consequence of the long‐term exposure (175 to 376 days) at 70°C. The long‐term exposure stiffened several of the polyvinylidene fluoride resins and occasionally made them less ductile. The poly(ethylene‐co‐chlorotrifluoroethylene) also became stiffer, but it was otherwise unaffected as far as observation by the other available techniques was concerned. 相似文献
994.
扩散加权图像中的噪声为莱斯噪声并且图像本身含有丰富的边界信息,因而要求对DWI图像有效降噪的同时,能够较好地保留图像的边界信息。由于BEMD算法可将图像分解为细节图像及余项图像,其所分解的细节图像包括DWI图像的边界信息以及主噪声,而余项图像则描述图像的趋势信息。因此,提出一种将二维经验模态分解算法与改进的维纳滤波器相结合的降噪算法,并将该算法应用于DWI图像的降噪中。通过实验,将所提出的算法与其他算法应用于DWI图像的降噪处理,并通过对结果的分析比较证明所提出的算法能够更有效地对DWI图像进行降噪处理。 相似文献
995.
阐述了要把去除污渍的能力转化成自由生活方式的源动力和妈妈对孩子的培育与关爱融人到每件干净的衣物中,通过一系列广告战役和概念营销捕获目标消费群体的心。 相似文献
996.
997.
Jan‐Chan Huang 《应用聚合物科学杂志》2004,91(5):2894-2902
Experimental values of the Flory–Huggins parameter, χ, between polymers and solvents, are frequently used to determine the solubility parameters of the polymers. A method using nonlinear curve fitting of RTχ/V was compared to the linear regression method commonly used. It was found that the formulas for the solubility parameter were the same, but the linear method produced a slightly different entropy term. The nonlinear method gave a lower correlation coefficient and wider confidence intervals and was more effective at distinguishing systems than the linear model. The effect of the deviation of probes in the solubility parameter model is discussed. Using probes with low solubility parameters to measure the polymer solubility parameter gave wider confidence intervals. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2894–2902, 2004 相似文献
998.
We used three kinds of alkyl diallyl ammonium salts (methyl, ethyl, and propyl) in combination with dimethyloldihydroxyethyleneurea (DMDHEU) as crosslinking agents. The nitrogen content, dry crease recovery angle (DCRA), moisture regain, and wicking height for the DMDHEU/alkyl diallyl ammonium salts were in the order of ? CH3 > ? C2H5 > ? C3H7, but the wet crease recovery angle (WCRA) and tensile strength retention (TSR) were in the opposite order at the same resin concentration. For the same DCRA and TSR, the WCRA values for only DMDHEU were lower than those for DMDHEU/alkyl diallyl ammonium salts, and the WCRA values for DMDHEU/alkyl diallyl ammonium salts were in the order of ? C3H7 > ? C2H5 > ? CH3. Both the ? OH group of the cellulose and DMDHEU could react with the vinyl or epoxy groups of the alkyl diallyl ammonium salts during the pad–dry–cure process. The surface migration for DMDHEU/alkyl diallyl ammonium salts was in the order of ? CH3 > ? C2H5 > ? C3H7. Fabrics treated with DMDHEU/alkyl diallyl ammonium salts showed good antibacterial properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1662–1669, 2003 相似文献
999.
1000.
Yongwon Seo Sung-Ho Jo Ho-Jung Ryu Hee Dal Bae Chong Kul Ryu Chang-Keun Yi 《Korean Journal of Chemical Engineering》2007,24(3):457-460
A bubbling fluidized bed reactor was used to study CO2 capture from flue gas by using a potassium-based solid sorbent, sorbKX35 which was manufactured by the Korea Electric Power
Research Institute. A dry sorbent, sorbKX35, consists of K2CO3 for absorption and supporters for mechanical strength. To increase initial CO2 removal, some amount of H2O was absorbed in the sorbent before injecting simulated flue gas. It was possible to achieve 100% CO2 removal for more than 10 minutes at 60°C and a residence time of 2 s with H2O pretreatment. When H2O pretreatment time was long enough to convert K2CO3 of sorbKX35 into K2CO3 · 1.5H2O, CO2 removal was excellent. The results obtained in this study can be used as basic data for designing and operating a large scale
CO2 capture process with two fluidized bed reactors.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献