全文获取类型
收费全文 | 255篇 |
免费 | 16篇 |
专业分类
化学工业 | 84篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 3篇 |
能源动力 | 18篇 |
轻工业 | 49篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 66篇 |
冶金工业 | 6篇 |
原子能技术 | 3篇 |
自动化技术 | 20篇 |
出版年
2023年 | 15篇 |
2022年 | 23篇 |
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 14篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 5篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有271条查询结果,搜索用时 877 毫秒
91.
Effect of chemical composition on the flocculation dynamics of latex-based synthetic activated sludge 总被引:1,自引:0,他引:1
This study investigates the effect of calcium, alginate, fibrous cellulose, and pH on the flocculation dynamics and final properties of synthetic activated sludges. A laboratory-scale batch reactor, fed with standard synthetic sludges was used. The effects of varying calcium concentration (5-25 mM), alginate concentration (25-125 mg/L), fibrous cellulose concentration (0.2-0.8 g/L) and pH (3-9) on the sludge characteristics were studied by varying one parameter whilst keeping the others constant. The results from experiments indicated that the calcium, alginate, fibrous cellulose, and pH had the critical effect on the aggregation rate, flocs size, and made the improvement of the final properties of sludge. Dynamic measurements have established the optimum conditions for floc formation and can accurately reflect the state of formation of the synthetic activated sludge flocs. These correlate well with measurements of settleability and turbidity of the synthetic activated sludge. The results of this study support the bonding theory and indicate that formation of cations-polymer complexes and polymer gelation are important means of flocculation. The development of synthetic activated sludges is suggested also to be a possible surrogate for studying the final properties of activated sludge. 相似文献
92.
Michelle Savescu A.H. Bhrawy A.A. Alshaery E.M. Hilal Kaisar R. Khan M.F. Mahmood 《Journal of Modern Optics》2013,60(5):441-458
This paper addresses solitons in nonlinear directional couplers in non-Kerr law media, with spatio-temporal dispersion. Both twin-core couplers as well as multiple-core couplers are studied. The nonlinearities studied are Kerr law, power law, parabolic law, dual-power law and log law. Bright, dark and singular soliton solutions of the governing equation are studied. 相似文献
93.
Osman I. Osman Abdulrahman O. Alyoubi Shabaan A. K. Elroby Rifaat H. Hilal Saadullah G. Aziz 《International journal of molecular sciences》2012,13(11):15360-15372
The MP2 and DFT/B3LYP methods at 6-311++G(d,p) and aug-cc-pdz basis sets have been used to probe the origin of relative stability preference for eclipsed acetaldehyde over its bisected counterpart. A relative energy stability range of 1.02 to 1.20 kcal/mol, in favor of the eclipsed conformer, was found and discussed. An NBO study at these chemistry levels complemented these findings and assigned the eclipsed acetaldehyde preference mainly to the vicinal antiperiplanar hyperconjugative interactions. The tautomeric interconversion between the more stable eclipsed acetaldehyde and vinyl alcohol has been achieved through a four-membered ring transition state (TS). The obtained barrier heights and relative stabilities of eclipsed acetaldehyde and the two conformers of vinyl alchol at these model chemistries have been estimated and discussed. 相似文献
94.
Cripto-1 is an essential protein for human development that plays a key role in the early phase of gastrulation in the differentiation of an embryo as well as assists with wound healing processes. Importantly, Cripto-1 induces epithelial to mesenchymal transition to turn fixed epithelial cells into a more mobile mesenchymal phenotype through the downregulation of epithelial adhesion molecules such as E-cadherin, occludins, and claudins, and the upregulation of mesenchymal, mobile proteins, such as N-cadherin, Snail, and Slug. Consequently, Cripto-1’s role in inducing EMT to promote cell motility is beneficial in embryogenesis, but detrimental in the formation, progression and metastasis of malignant tumors. Indeed, Cripto-1 is found to be upregulated in most cancers, such as breast, lung, gastrointestinal, hepatic, renal, cervical, ovarian, prostate, and skin cancers. Through its role in EMT, Cripto-1 can remodel cancer cells to enable them to travel through the extracellular matrix as well as blood and lymphatic vessels to metastasize to different organs. Additionally, Cripto-1 promotes the survival of cancer stem cells, which can lead to relapse in cancer patients. 相似文献
95.
Serkan Yildiz Serkan Kivrak Gokhan Arslan 《Civil Engineering and Environmental Systems》2017,34(3-4):264-277
Urban renewal programmes offer an opportunity to improve the environmental sustainability of urban areas by creating well-designed and well-constructed built environments. In this study, the contributions of built environment design elements to environmental sustainability were evaluated through a questionnaire survey with the participation of 323 people who previously worked in urban renewal projects. Implementing factor analysis, interrelated elements have been gathered under five factors: ‘transportation and accessibility’, ‘conservation of natural resources’, ‘built environment quality’, ‘supporting social life’ and ‘high-density usage’. To identify the importance weights of these factors, analytic hierarchy process (AHP) analysis was carried out with 40 academics and practitioners. Based on the results, ‘conservation of natural resources’ was found as the most important factor affecting the environmental sustainability of urban renewal projects. It is expected that the results of this study shall guide a wide range of urban renewal stakeholders, extending from designers to citizens, along the path of creating environmentally sustainable cities. 相似文献
96.
The minimum fluidization velocity of beds has been determined experimentally in beds of 0.089 m and 0.29 m diameters, respectively. The particles studied had sizes ranging from 100 μm to 1 mm in diameter, and densities from 1128 to 11400 kg/m3. Three distributors were used in the experimental scheme, each perforated by holes of 0.8 mm in diameter but with varying hole densities, as well as a porous plate. It was found that the minimum fluidization velocity was affected by both the diameter and distributor used. The effect of vertical tubular inserts on the minimum fluidization velocity was investigated in the 0.29 m diameter bed. The experimental data in the large bed, using four distributors, were parameterized within experimental error. 相似文献
97.
Belgin Sever Halilibrahim Ciftci Hasan DeMirci Hilal Sever Firdevs Ocak Burak Yulug Hiroshi Tateishi Takahisa Tateishi Masami Otsuka Mikako Fujita Aye Nazl Baak 《International journal of molecular sciences》2022,23(5)
Amyotrophic lateral sclerosis (ALS) is a rapidly debilitating fatal neurodegenerative disorder, causing muscle atrophy and weakness, which leads to paralysis and eventual death. ALS has a multifaceted nature affected by many pathological mechanisms, including oxidative stress (also via protein aggregation), mitochondrial dysfunction, glutamate-induced excitotoxicity, apoptosis, neuroinflammation, axonal degeneration, skeletal muscle deterioration and viruses. This complexity is a major obstacle in defeating ALS. At present, riluzole and edaravone are the only drugs that have passed clinical trials for the treatment of ALS, notwithstanding that they showed modest benefits in a limited population of ALS. A dextromethorphan hydrobromide and quinidine sulfate combination was also approved to treat pseudobulbar affect (PBA) in the course of ALS. Globally, there is a struggle to prevent or alleviate the symptoms of this neurodegenerative disease, including implementation of antisense oligonucleotides (ASOs), induced pluripotent stem cells (iPSCs), CRISPR-9/Cas technique, non-invasive brain stimulation (NIBS) or ALS-on-a-chip technology. Additionally, researchers have synthesized and screened new compounds to be effective in ALS beyond the drug repurposing strategy. Despite all these efforts, ALS treatment is largely limited to palliative care, and there is a strong need for new therapeutics to be developed. This review focuses on and discusses which therapeutic strategies have been followed so far and what can be done in the future for the treatment of ALS. 相似文献
98.
99.
S Chan SS Chin K Kartha DR Nordli RR Goodman TA Pedley SK Hilal 《Canadian Metallurgical Quarterly》1996,17(9):1725-1731
PURPOSE: To investigate the phenomenon of reversible increased signal intensity of medial temporal lobe structures and cerebral neocortex seen on MR images of six patients with recent prolonged seizure activity. METHODS: After excluding patients with known causes of reversible signal abnormalities (such as hypertensive encephalopathy), we retrospectively reviewed the clinical findings and MR studies of six patients whose MR studies showed reversible signal abnormalities. MR pulse sequences included T2-weighted spin-echo coronal views or conventional short-tau inversion-recovery coronal images of the temporal lobes. RESULTS: All six MR studies showed increased signal intensity within the medial temporal lobe, including the hippocampus in five studies. All follow-up MR examinations showed partial or complete resolution of the hyperintensity within the medial temporal lobe and the neocortex. In one patient, results of a brain biopsy revealed severe cerebral cortical gliosis. Temporal lobectomy performed 4 years later showed moderate cortical gliosis and nonspecific hippocampal cell loss and gliosis. CONCLUSION: Significant hyperintensity within the temporal lobe is demonstrable on MR images after prolonged seizure activity, suggestive of seizure-induced edema or gliosis. Damage to medial temporal lobe structures by prolonged seizure activity indicates a possible mechanism of epileptogenic disorders. 相似文献
100.
The electrodeposition of aluminium was carried out successfully in AlCl3-LiAlH4/tetrahydrofuran-toluene solutions. The kinetic parameters controlling the cathodic deposition and anodic dissolution of aluminium were derived. The effect of the total concentration of aluminium and the molar ratio of AlCl3 to LiAlH4 on the current density-potential behaviour of the rotating disc aluminium electrode was also studied. A detailed mechanism for the electrode reactions was suggested. 相似文献