全文获取类型
收费全文 | 4232篇 |
免费 | 208篇 |
国内免费 | 51篇 |
专业分类
电工技术 | 74篇 |
综合类 | 41篇 |
化学工业 | 857篇 |
金属工艺 | 100篇 |
机械仪表 | 83篇 |
建筑科学 | 108篇 |
矿业工程 | 9篇 |
能源动力 | 155篇 |
轻工业 | 329篇 |
水利工程 | 45篇 |
石油天然气 | 33篇 |
武器工业 | 7篇 |
无线电 | 343篇 |
一般工业技术 | 377篇 |
冶金工业 | 1593篇 |
原子能技术 | 38篇 |
自动化技术 | 299篇 |
出版年
2024年 | 6篇 |
2023年 | 23篇 |
2022年 | 73篇 |
2021年 | 109篇 |
2020年 | 78篇 |
2019年 | 100篇 |
2018年 | 123篇 |
2017年 | 113篇 |
2016年 | 119篇 |
2015年 | 98篇 |
2014年 | 128篇 |
2013年 | 250篇 |
2012年 | 160篇 |
2011年 | 181篇 |
2010年 | 148篇 |
2009年 | 160篇 |
2008年 | 136篇 |
2007年 | 115篇 |
2006年 | 107篇 |
2005年 | 80篇 |
2004年 | 75篇 |
2003年 | 41篇 |
2002年 | 51篇 |
2001年 | 55篇 |
2000年 | 52篇 |
1999年 | 67篇 |
1998年 | 483篇 |
1997年 | 304篇 |
1996年 | 196篇 |
1995年 | 121篇 |
1994年 | 91篇 |
1993年 | 90篇 |
1992年 | 35篇 |
1991年 | 28篇 |
1990年 | 26篇 |
1989年 | 35篇 |
1988年 | 39篇 |
1987年 | 22篇 |
1986年 | 20篇 |
1985年 | 28篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 21篇 |
1980年 | 30篇 |
1979年 | 8篇 |
1977年 | 61篇 |
1976年 | 127篇 |
1975年 | 6篇 |
1972年 | 7篇 |
排序方式: 共有4491条查询结果,搜索用时 15 毫秒
1.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
3.
4.
5.
Mohamed A.El-Nemr Ibrahim M.A.Ismail Nabil M.Abdelmonem Ahmed El Nemr Safaa Ragab 《中国化学工程学报》2021,36(8):199-222
Watermelon peel residues were used to produce a new biochar by dehydration method. The new biochar has undergone two methods of chemical modification and the effect of this chemical modification on its ability to adsorb Cr(VI) ions from aqueous solution has been investigated. Three biochars, Melon-B, Melon-BO-NH_2 and Melon-BO-TETA, were made from watermelon peel via dehydration with 50% sulfuric acid to give Melon-B followed by oxidation with ozone and amination using ammonium hydroxide to give Melon-BO-NH_2 or Triethylenetetramine(TETA) to give Melon-BO-TETA. The prepared biochars were characterized by BET, BJH,SEM, FT-IR, TGA, DSC and EDAX analyses. The highest removal percentage of Cr(VI) ions was 69% for Melon-B,98% for Melon-BO-NH_2 and 99% for Melon-BO-TETA biochars of 100 mg·L~(-1) Cr(VI) ions initial concentration and 1.0 g·L~(-1) adsorbents dose. The unmodified biochar(Melon-B) and modified biochars(Melon-BO-NH_2 and Melon-BO-TETA) had maximum adsorption capacities(Qm) of 72.46, 123.46, and 333.33 mg·g~(-1), respectively.The amination of biochar reduced the pore size of modified biochar, whereas the surface area was enhanced.The obtained data of isotherm models were tested using different error function equations. The Freundlich,Tempkin and Langmuir isotherm models were best fitted to the experimental data of Melon-B, Melon-BO-NH_2 and Melon-BO-TETA, respectively. The adsorption rate was primarily controlled by pseudo-second–order rate model. Conclusively, the functional groups interactions are important for adsorption mechanisms and expected to control the adsorption process. The adsorption for the Melon-B, Melon-BO-NH_2 and Melon-BO-TETA could be explained for acid–base interaction and hydrogen bonding interaction. 相似文献
6.
Syafikah Huda Paiman Mukhlis A Rahman Khairul Hamimah Abas Azian Abd Aziz Ahmad Fauzi Ismail Mohd Hafiz Dzarfan Othman Juhana Jaafar Mohammad Noorul Anam Mohd Norddin 《化学工程与技术》2019,42(6):1321-1329
Removal by absorptive ceramic membranes can simultaneously absorb and separate metal ions from water. Alumina/yttria‐stabilized zirconia (Al2O3/YSZ) hollow‐fiber membranes, fabricated using phase inversion and sintering process, were deposited with iron oxide by an in‐situ hydrothermal process. The results showed that α‐Fe2O3 was produced and incorporated across the membranes. A reduction in flux was recorded with the deposition of α‐Fe2O3. However, it improved the adsorption capacity for heavy metal adsorption. The adsorption‐separation test demonstrated that the optimized membrane is able to completely remove Pb(II) ions after two hours. 相似文献
7.
8.
A cost comparison of balloon angioplasty and stenting versus endarterectomy for the treatment of carotid artery stenosis 总被引:1,自引:0,他引:1
WD Jordan GD Roye WS Fisher D Redden HA McDowell 《Canadian Metallurgical Quarterly》1998,27(1):16-22; discussion 22-4
PURPOSE: Percutaneous transluminal angioplasty with stenting (PTAS) of the carotid artery has been advocated as an alternative treatment for high-grade stenosis. Rationale for this approach includes less morbidity, shorter recovery, and lower cost when compared with carotid endarterectomy (CEA). METHODS: The clinical results and hospital charges of patients who underwent elective treatment for carotid stenosis were reviewed. During a concurrent 14-month period, 218 patients were admitted 229 times for 234 procedures for the treatment of 239 carotid bifurcation stenoses, 109 by PTAS and 130 by CEA. Hospital charges were reviewed for each hospitalization and were categorized according to radiology, operating room, cardiac catheterization laboratory, and all other hospital charges. RESULTS: The combined incidence of postprocedure strokes and deaths were: PTAS, eight strokes (7.7%) and one death (0.9%); CEA, two strokes (1.5%) and two deaths (1.5%). Total hospital charges per admission for the two groups were $30,140 for PTAS and $21,670 for CEA. The average postprocedure length of stay for PTAS was 2.9 days (median, 2 days) and for CEA was 3.1 days (median, 3 days). Cardiac catheterization laboratory charges for the PTAS group were $12,968, whereas the operating room charges for the CEA group were $4263. When hospitalizations that were extended by complications were excluded, the average total charges for the PTAS group (n = 84) dropped to $24,848 (mean length of stay, 1.9 days) and for the CEA group (n = 111) to $19,247 (mean length of stay, 2.6 days). CONCLUSIONS: After evaluating hospital charges, PTAS for the treatment of carotid stenosis cannot currently be justified on the basis of reduced costs alone. With future cost-containing measures, total hospital charges can be reduced in both groups. 相似文献
9.
10.