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91.
离子液体催化C_5馏分中二烯烃的聚合反应 总被引:1,自引:0,他引:1
合成了多种基于1-丁基-3-甲基咪唑阳离子的离子液体,并作为裂解C5馏分中混合二烯烃聚合反应的介质。考察了离子液体种类、反应温度、反应时间和添加Lew is酸对混合二烯烃聚合反应的影响。实验结果表明,以硝酸根为阴离子的离子液体对混合二烯烃的聚合反应具有一定的阻聚作用;以六氟磷酸根为阴离子的离子液体能明显促进混合二烯烃的聚合反应,提高二聚物的含量;添加Lew is酸(质量分数为1%的ZnCl2)的离子液体对混合二烯烃的聚合反应具有更明显的促进作用,其效果仅次于酸性氯铝酸类离子液体,反应温度以30℃以下为宜,温度过高将促使二聚物进一步聚合,形成三聚物乃至多聚物,降低二聚物的含量。 相似文献
92.
93.
Thorough washing of a VPI-5 synthesized with n-dipropylamine as template improves greatly its thermal stability while no major change is observed in the template content. A detailed study of the influence of the pretreatment conditions shows that in order to obtain a high thermal stability (up to at least 960 °C) two parameters are of importance. The removal of both the template and the adsorbed water requires either a low heating rate at atmospheric pressure or a low pressure (less than 3 Torr) when the heating rate is 300 ° per hour. 相似文献
94.
Michael W. Anderson 《Topics in Catalysis》1996,3(1-2):195-220
The power of solid-state NMR for the interrogation of porous catalytic materials is illustrated using three examples. First,
for the investigation of catalytic processes occurring within the confines of a microporous catalyst NMR is shown to reveal
both the details of shape-selectivity and the nature of internal surface species. Second, NMR is shown to be a powerful short-range
tool to reveal precise structural information on highly disordered microporous titanosilicates. Despite long-range disorder
the short-range order is maintained and can be easily studied. Finally, the same utility of probing short-range chemical phenomena
is shown to be crucial for the investigation of novel-ordered-amorphous-mesoporous materials known generically as M41S. This
class of material is currently one of the most important with potential catalytic application. 相似文献
95.
Investigation of the reaction mechanism of chloromethane on ZSM5 is a new topic. In this work an in situ FTIR technique was employed to study the conversion processes of chloromethane, the active sites on HZSM5, and the desorption state of surface species. The catalytic conversion of chloromethane to higher hydrocarbons was also studied. It is demonstrated that chloromethane can be reversibly adsorbed on acidic sites of HZSM5 at room temperature. At 100°C chloromethane is irreversibly and dissociatively adsorbed on the strong acidic sites of HZSM5, on which surface methoxyl is formed as proved by infrared characteristic C-H stretchings of-CH3 at 2960 and 2870 cm–1. Alkoxyls are produced and adsorbed on the catalyst surface as characterized by the infrared absorption bands of -CH2-groups at 1460 and 2930 cm–1. At 100°C the adsorbed methoxyl and alkoxyls are the main surface species, and a small amount of aromatics might exist as detected by a characteristic absorption band at 1510 cm–1. Between 100 and 200°C the adsorbed surface methoxyl and alkoxyls are converted to aromatics, and the occupied OH groups partially appear. At temperature higher than 300°C the adsorbed aromatics are thermally desorbed into the gas phase. Aromatics and alkanes are the main products in catalytic conversion. These results reveal that the formation of aromatics from methoxyl and alkoxyls is easier than the desorption of aromatics from HZSM5 catalyst. An alkoxyl mechanism is proposed for the conversion of chloromethane on HZSM5 based upon the experimental results and the three assumptions: (a) The primary C-C bond is formed from surface methoxyl groups via the methoxyl group polarization and C-H bond weakening, (b) The adsorbed alkoxyls are converted to aromatics via hydrogen transfer and bond rearrangement similar to the conventional carbenium ion mechanism for the aromatization of olefins and alkanes on HZSM5. The hydrogen atoms from the aromatization stimulate the desorption of alkoxyls to alkanes. (c) At temperature higher than 300°C surface reactions and desorption of adsorbed species take place simultaneously, determining the product distribution in the catalytic conversion. 相似文献
96.
以江苏省南通市为研究区,利用采样点实测数据,借助GRNN神经网络模型并结合3S技术对农田土壤重金属的空间动态分布进行了深入研究。结果表明,GRNN神经网络模型能够智能地学习各个采样点的空间位置与该点各重金属含量之间的映射关系,并能够稳健地对各个空间插值点处的土壤重金属含量进行预测;结果显示南通市农田土壤重金属污染总体较轻,但也存在局部地区的严重污染。在运用GRNN神经网络模型进行空间插值了解重金属空间动态分布的基础上,可以根据污染的状况确定农产品的生产布局和规划。 相似文献
97.
98.
Two commercial SCR catalysts, with a nominal W content of about 9 wt.% and a V nominal content of 0.55 and 1.8 wt.%, respectively, were contacted with different amounts of Na and K and with HCl vapours in order to simulate poisoning by species more specifically contained in exhaust gases from MSW combustion. Catalysts were characterised using XRD analysis, SEM/EDX analysis, BET and pore size distribution measurements, NH3 TPD, TG analysis. Poisoning agents do not cause loss of surface area nor pore occlusion. A significant loss of surface acidity was observed upon alkali metals poisoning whereas a decreasing of vanadium content was observed for the more concentrated catalysts upon HCl poisoning. Catalysts deactivation is proportional to the number of acid sites neutralised by alkali metals adsorbing ammonia in the temperature range typical of SCR process. HCl promotes the formation of new acid sites showing a lower activity compared to the original one. 相似文献
99.
100.
利用抽余碳五馏份制备TAME 总被引:4,自引:0,他引:4
探索了以抽余C5为原料经与甲醇醚化制TAME的过程。试验表明,在国产催化剂D54型大孔阳离子交换树脂存在下,在反应温度60℃、LHSV2.4h-1、甲醇/异戊烯物质的量比1.00、反应压力0.2MPa的条件下,抽余C5中的异戊烯可与甲醇反应生成醚,异戊烯的转化率达63.26%,TAME的选择性可达99.61%。 相似文献