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291.
探讨了聚丙烯酰胺、葡萄糖、高岭土、AlCl3、腐植酸钠、水溶性苯酚—甲醛树脂和自制的水溶性树脂A (简称为树脂A)等对水玻璃改性的影响。结果表明 ,树脂A使焦炭粉冷固成型的球团的生球和干球强度明显提高。并确定了其较佳配方 :水与水玻璃的重量比为 4∶6 ,其总用量为 1 6 % (占干焦炭粉的重量百分比 ) ;树脂A用量为 0 2 4 % (占干焦炭粉的重量百分比 )。在此较佳条件下 ,所制球团的生球和干球强度 ,与用未改性水玻璃 (其中水与水玻璃的重量比为 3∶7,其总用量为 1 6 %(占干焦炭粉的重量百分比 )所制球团的生球和干球强度 ,几乎相等 ,但前者球团的耐水性以及耐热性有明显提高 相似文献
292.
作者分离到硅酸盐细菌JF88菌株,经鉴定为邻单胞菌属(Plesiomonas),经28℃110RPM培养144h后,用 7520型分光光度计比色,测得磷转化强度是磷细菌MB1的15.79倍,用直接计数法测得JF88菌 株的生长超过MB1菌株。该菌株在阿须贝无氮培养基上生长良好,具有良好的应用前景。 相似文献
293.
294.
Synthesis of cage-like octa(trimethylsiloxy)silsesquioxane 总被引:2,自引:0,他引:2
Cage-like octa(trimethylsiloxy)silsesquioxane [ (Me3SiO)SiO1.5]8 has been synthesized via the trimethylsilylation of cubic tetramethylammonium silicate octamer [(Me4NO)-SiO1.5]8 with chlorotrimethylsilane. The silicate octamer can be selectively formed by the reaction of tetraethoxysilane Si(OEt)4 with aqueous tetramethylammonium hydroxide in equal molar ratio. Elementary analysis, FT-IR,1H,13C,29Si NMR are used to characterize these silsesquioxanes. 相似文献
295.
赵占西 《河海大学常州分校学报》1995,(3)
本文测定了水玻璃白云石砂的残留强度曲线,并提出了进一步改进其溃散性的方法。证明水玻璃白云石砂的溃散性与铸件的大小、壁厚、浇注温度、吃砂量和打箱时间有关。 相似文献
296.
Conclusions The total proton load found in these ecosystems exceeds by far the known rates of buffering in soils by silicate weathering and release of basic cations (see above).Under the present proton load most forest soils will therefore acidify and besides losses of nutrients the occurrence of possible toxic ions in the soil unavoidable (Al-buffer range)20, 21.The proportion of the total proton load of the soil that is represented by the internal production emphasizes the importance of acid deposition as main cause of soil acidification and destabilization of forest ecosystems under Central European conditions. 相似文献
297.
界面层结构对硅灰石填充聚丙烯结晶行为和形态的影响 总被引:1,自引:0,他引:1
采用DSC和偏光显微镜技术对以硅烷类KH-550,KH-570和钛酸酯类NDZ-201等偶联剂处理的硅灰石填充聚丙烯的结晶行为和形态进行了研究,结果表明,由于偶联剂结构各异,将形成不同的填料与树脂间的界面层结构,产生不同的界面效应,从而影响其结晶成核与生长过程.KH-550提高了硅灰石异相成核的能力,使结晶温度升高,结晶速率加快,晶粒变小,分布变窄;NDZ-201则相反,而KH-570影响不大. 相似文献
298.
硅酸钠对油井水泥缓凝剂具有促凝和助缓凝两种相互矛盾的作用,为满足固井施工安全性的需求,研究高模数硅酸钠对不同缓凝剂的影响。在分析硅酸钠对不同缓凝剂水泥浆体系水化机制影响的基础上,研究硅酸钠模数、硅酸钠加量等因素对硅酸钠助缓凝效果的影响。结果表明:硅酸钠对加有缓凝剂柠檬酸、酒石酸、氧化锌的水泥浆起到促凝作用,对葡萄糖酸钠起到助缓凝作用;模数为1的硅酸钠缩短了加有葡萄糖酸钠水泥浆的稠化时间,模数为2.2与3.3的硅酸钠延长了水泥浆的稠化时间;在葡萄糖酸钠加量为0.05%与0.075%的情况下,硅酸钠对静止的水泥浆起促凝作用,加量提高对流动的水泥浆起到先缓凝后促凝的作用,缓解了现场固井后候凝时间长的问题;加有硅酸钠的复配缓凝剂与葡萄糖酸钠相比,大温差适应能力好,有利于缩短候凝时间、改善长封固段井的固井质量。 相似文献
299.
Clay mineral composition and their sources for the fluvial sediments of Taiwanese rivers 总被引:3,自引:0,他引:3
Li ChuanShun Shi XueFa Kao ShuhJi Chen MinTe Liu YanGuang Fang XiSheng Lü HuaHua Zou JianJun Liu ShengFa Qiao ShuQing 《科学通报(英文版)》2012,57(6):673-681
Located at the collision boundary between the Philippine Sea Plate and the Eurasian Continental Plate,the island of Taiwan is generally recognized as an important example in the MARGINS Program Science Plan and source-to-sink research because of its high tectonic activity,heavy rainfall and unique geography.Large suspended sediment loads are transported to the adjacent ocean by Taiwanese rivers every year,making Taiwan an important source of sediments into the adjacent seas and a natural laboratory for studying the systemic movement of fluvial sediments from source to sink.A detailed study on the clay mineral composition of surface sediments collected from the drainage basins of 12 Taiwanese rivers using X-ray diffraction methods was conducted.Our results indicated that the clay mineral assemblages consisted dominantly of illite(approximately 73%) and chlorite(approximately 24%),with lesser abundances of kaolinite(approximately 3%) and even lower levels of smectite from the Danshuei River sediments in northwestern Taiwan.The Jhuoshuei River sediments from western Taiwan contained clay mineral assemblages that consisted of illite(approximately 75%) and chlorite(approximately 25%),but they lacked kaolinite and smectite.In southwestern Taiwan,the clay mineral assemblages were dominated by illite(approximately 75%) and chlorite(approximately 23%),but had a low abundance of kaolinite(generally < 2%) and no smectite.The clay mineral assemblages in eastern Taiwan are obviously different from those in western parts of the island.The most noticeable difference is that the average abundance of chlorite in the Hualien River from eastern Taiwan was the highest(approximately 48%) of all the Taiwanese rivers.We concluded that,in general,the clay mineral assemblages in Taiwanese rivers were mainly composed of illite and chlorite with kaolinite and smectite being scarce,and these trends are different from those in China’s mainland rivers.The clay mineral composition shown in this study was primarily determined by the properties of the bedrock,and the differential weathering intensities of the drainage area.The surface sediments in Taiwan’s rivers showed a greater abundance of illite and chlorite because the outcropped rocks were mainly composed of Tertiary sedimentary rocks,especially sandstone,shale and slate,and show strong physical weathering.The relatively high relief and more abundant rainfall also caused the clay minerals in the fluvial sediments to be transported to the estuaries down rivers from the mountains and then delivered to the adjacent seas by currents and waves over a shorter time scale. 相似文献
300.
首先分析了边坡工程存在的耐久性问题,提出边坡工程抗疲劳、抗风化和抗腐蚀设计的思路.边坡工程存在合理的服役寿命,在风化、动荷载作用以及腐蚀环境下,边坡岩土的工程性能和锚固体性能将产生劣化,直接影响到边坡工程的安全性及耐久性.边坡工程耐久性设计是确保边坡长期稳定的重要措施,应全面考虑时间效应的抗腐蚀、抗疲劳、抗风化等问题的... 相似文献