全文获取类型
收费全文 | 1725篇 |
免费 | 202篇 |
国内免费 | 64篇 |
专业分类
电工技术 | 92篇 |
综合类 | 78篇 |
化学工业 | 325篇 |
金属工艺 | 60篇 |
机械仪表 | 68篇 |
建筑科学 | 101篇 |
矿业工程 | 35篇 |
能源动力 | 73篇 |
轻工业 | 157篇 |
水利工程 | 25篇 |
石油天然气 | 21篇 |
武器工业 | 15篇 |
无线电 | 219篇 |
一般工业技术 | 323篇 |
冶金工业 | 106篇 |
原子能技术 | 19篇 |
自动化技术 | 274篇 |
出版年
2024年 | 11篇 |
2023年 | 52篇 |
2022年 | 117篇 |
2021年 | 160篇 |
2020年 | 118篇 |
2019年 | 103篇 |
2018年 | 97篇 |
2017年 | 89篇 |
2016年 | 84篇 |
2015年 | 92篇 |
2014年 | 112篇 |
2013年 | 125篇 |
2012年 | 113篇 |
2011年 | 118篇 |
2010年 | 64篇 |
2009年 | 58篇 |
2008年 | 59篇 |
2007年 | 58篇 |
2006年 | 60篇 |
2005年 | 39篇 |
2004年 | 33篇 |
2003年 | 29篇 |
2002年 | 35篇 |
2001年 | 25篇 |
2000年 | 19篇 |
1999年 | 18篇 |
1998年 | 16篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 3篇 |
1993年 | 9篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有1991条查询结果,搜索用时 15 毫秒
71.
以生产淀粉的副产物豌豆蛋白粉为原料,研究了中性蛋白酶酶解条件对豌豆蛋白乳化性的影响.首先通过单因素试验研究了加酶量、反应时间、底物浓度、反应温度、pH值对豌豆蛋白乳化活性和乳化稳定性的影响;在单因素试验的基础上设计响应面试验,研究各因素及其交互作用对豌豆蛋白乳化性的影响,优化出的最佳酶解条件为:加酶量0.13%、反应时间32.5 min、pH8.0、反应温度52.8℃,此时豌豆蛋白的乳化活性为35.82 m2/g,乳化稳定性为45.88 min,比改性前豌豆蛋白的乳化性有了明显提高. 相似文献
72.
73.
The provision of a downcomer to classical turbulent bed Contactor (TBC) increases the gas treating capacity of the equipment. When the downcomer is provided, it is expected that all the liquid passes through the downcomer only without any liquid flow through the distributor. In the present study, the operational regime for the flow of liquid only through the downcomer is experimentally evaluated for various geometric parameters and particle characteristics. It is observed that the preferred operational regime without dumping and weeping increases with an increase in Archimedes number and downcomer diameter, and decreases with an increase in static bed height and downcomer weir height. Correlations are proposed to satisfactorily predict experimentally observed operational regime. 相似文献
74.
Desulfurization of digester gas: prediction of activated carbon bed performance at low concentrations of hydrogen sulfide 总被引:2,自引:0,他引:2
Three chemically modified/impregnated activated carbons (supplied by manufactures) were used for adsorption–catalytic removal of hydrogen sulfide from digester gas. The performance of samples was studied in dynamic conditions at 1000, 2000 and 5000 ppm of H2S in digester gas. The results showed differences in the H2S removal capacities related to the type of carbon and conditions of the experiment. A decrease in H2S concentration resulted in an increase in a breakthrough capacity, which is linked to slow kinetics of oxidation process. No significant changes were observed when the oxygen content increased from 1 to 2% and the temperature from 38 to 60 °C. On the surface of carbons studied hydrogen sulfide was oxidized predominantly to sulfur, which was deposited in micropores, either on the walls or at the pore entrances. The capacities at low concentrations, 50 and 100 ppm, of H2S were determined using an approach based on known theoretical solution of a dynamic model where the parameters of the model were determined from the experimental data at a high concentration of an adsorbate. 相似文献
75.
76.
Nanoengineered biodegradable constructs based on synthetic and natural polymers enriched with hydroxyapatite (HA) nanoparticles have been found to mimic the extracellular matrix of bone tissue. The main objective of this study was to create biocomposite nanostructured scaffolds by incorporating collagen and HA nanoparticles into poly(L-lactic acid)-co-poly(?-caprolactone) by electrospinning. The fiber diameter of the composite PLCL/Col and PLCL/Col/HA fibers was smaller compared to PLCL. In vitro biocompatibility of the scaffolds studied using human fetal osteoblasts and EDX analysis showed high deposition of calcium on PLCL/Col/HA. The results shows that PLCL/Col/HA nanofibrous constructs have huge potential as substrates for bone regeneration. 相似文献
77.
Yanming Zhang Haidong Liu Siddharth Sundararaman Liping Huang Yunfeng Shi 《Journal of the American Ceramic Society》2022,105(2):958-965
Oxide glass, one of the most transformative materials in the modern world, breaks easily under load due to its brittleness. Using classical molecular dynamics simulations, we prepared amorphous alumina by consolidating glass nanoparticles at room temperature. We showed that consolidated amorphous alumina exhibits work hardening ability, hence deforms homogeneously and fractures via necking under tension, while amorphous alumina obtained from the traditional melt-quench process fractures catastrophically due to severe shear banding. This finding suggests that if processed properly, amorphous oxides could deform and fracture like ductile metals, which will significantly expand the applications of oxide glasses into new areas where load bearing or mechanical reliability is necessary. 相似文献
78.
Yanliang Zhou Qianjin Sai Zhenni Tan Congying Wang Xiuyun Wang Bingyu Lin Jun Ni Jianxin Lin Lilong Jiang 《中国化学工程学报》2022,43(3):177-184
The industrial manufacture of ammonia (NH3) using Fe-based catalyst works under rigorous conditions. For the goal of carbon-neutrality, it is highly desired to develop advanced catalyst for NH3 synthesis at mild conditions to reduce energy consumption and CO2 emissions. However, the main challenge of NH3 synthesis at mild conditions lies in the dissociation of steady NN triple bond. In this work, we report the design of subnanometer Ru clusters (0.8 nm) anchored on the hollow N-doped carbon spheres catalyst (Ru-SNCs), which effectively promotes the NH3 synthesis at mild conditions via an associative route. The NH3 synthesis rate over Ru-SNCs (0.49% (mass) Ru) reaches up to 11.7 mmol NH3·(g cat)-1·h-1 at 400 ℃ and 3 MPa, which is superior to that of 8.3 mmol NH3·(g cat)-1·h-1 over Ru nanoparticle catalyst (1.20% (mass) Ru). Various characterizations show that the N2H4 species are the main intermediates for NH3 synthesis on Ru-SNCs catalyst. It demonstrates that Ru-SNCs catalyst can follow an associative route for N2 activation, which circumvents the direct dissociation of N2 and results in highly efficient NH3 synthesis at mild conditions. 相似文献
79.
利用SBR反应器,控制曝气量为0.3 L·min-1,通过改变N2∶O2比例,调节反硝化过程中DO浓度,以连续投加乙醇作为反硝化碳源,考察了低氧条件下NO-3N反硝化过程及N2O的产量。结果表明,DO对反硝化菌的活性具有明显的抑制作用。DO由0增至0.7 mg·L-1,NO-3N还原速率由18.12 mg N·(g MLSS)-1·h-1降至11.37 mg N·( gMLSS)-1·h-1,系统N2O产量由0.23 mg·L-1增至1.74 mg·L-1。其原因为:(1)较高的NO-2N浓度导致系统反硝化速率降低,N2O积累并释放;(2)DO对N2O还原酶活性具有明显的抑制作用。降低缺氧-好氧生物脱氮过程中缺氧反应器内部DO含量,是减少生物脱氮过程中N2O产量的关键因素。 相似文献
80.
Suk-Hwan Kang Jae-Hong Ryu Jin-Ho Kim P. S. Sai Prasad Jong Wook Bae Joo-Young Cheon Ki-Won Jun 《Catalysis Letters》2011,141(10):1464-1471