全文获取类型
收费全文 | 1238篇 |
免费 | 68篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 16篇 |
综合类 | 4篇 |
化学工业 | 327篇 |
金属工艺 | 34篇 |
机械仪表 | 32篇 |
建筑科学 | 24篇 |
能源动力 | 43篇 |
轻工业 | 53篇 |
水利工程 | 1篇 |
无线电 | 243篇 |
一般工业技术 | 222篇 |
冶金工业 | 103篇 |
原子能技术 | 2篇 |
自动化技术 | 220篇 |
出版年
2023年 | 11篇 |
2022年 | 26篇 |
2021年 | 35篇 |
2020年 | 16篇 |
2019年 | 24篇 |
2018年 | 27篇 |
2017年 | 31篇 |
2016年 | 37篇 |
2015年 | 33篇 |
2014年 | 71篇 |
2013年 | 107篇 |
2012年 | 59篇 |
2011年 | 72篇 |
2010年 | 64篇 |
2009年 | 76篇 |
2008年 | 66篇 |
2007年 | 69篇 |
2006年 | 56篇 |
2005年 | 42篇 |
2004年 | 37篇 |
2003年 | 36篇 |
2002年 | 34篇 |
2001年 | 22篇 |
2000年 | 21篇 |
1999年 | 16篇 |
1998年 | 48篇 |
1997年 | 29篇 |
1996年 | 17篇 |
1995年 | 17篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1970年 | 2篇 |
排序方式: 共有1324条查询结果,搜索用时 15 毫秒
31.
Hsiao T. H. Chen T. C. Jeng S. L. Chung T. J. Tsay L. W. 《Journal of Materials Engineering and Performance》2016,25(10):4317-4325
Journal of Materials Engineering and Performance - Microstructures of the heat-affected zone (HAZ) of a Gr. 91 steel weld were simulated to evaluate their effects on the creep life of the weld at... 相似文献
32.
Ching-Chao Liang Pi-Chen Lin Mei-Yueh Lee Szu-Chia Chen Shyi-Jang Shin Pi-Jung Hsiao Kun-Der Lin Wei-Hao Hsu 《International journal of molecular sciences》2016,17(8)
Patients with type 2 diabetes mellitus (DM) may experience chronic microvascular complications such as diabetic retinopathy (DR) and diabetic nephropathy (DN) during their lifetime. In clinical studies, serum uric acid concentration has been found to be associated with DR and DN. The goal of this study was to evaluate the relationship between the increases in serum uric acid level and the severity of DR and albuminuria in Taiwanese patients with type 2 DM. We recorded serum uric acid concentration, the severity of DR, and the severity of albuminuria by calculating urinary albumin-to-creatinine ratio (UACR) in 385 patients with type 2 DM. In multivariate logistic regression analysis, a high uric acid concentration was a risk factor for albuminuria (odds ratio (OR), 1.227; 95% confidence interval (CI) = 1.015–1.482; p = 0.034) and DR (OR, 1.264; 95% CI = 1.084–1.473; p = 0.003). We also demonstrated that there was a higher concentration of serum uric acid in the patients with more severe albuminuria and DR. In conclusion, an increased serum uric acid level was significantly correlated with the severity of albuminuria and DR in Taiwanese patients with type 2 DM. 相似文献
33.
Improving toughness of ultra-high molecular weight polyethylene with ionic liquid modified carbon nanofiber 总被引:1,自引:0,他引:1
Ionic liquids (ILs) with long alkyl substituted groups, including 1-docosanyl-3-methylimidazolium bromide (IL-1) and 1-docosanyl-3-methylimidazolium hexafluorophosphate (IL-2), were synthesized and used to modify the surface of carbon nanofibers (CNF). The nanocomposite film prepared by solution-blending of ionic liquid modified CNF (i-CNF) and ultrahigh molecular weight polyethylene (UHMWPE) displayed better toughness when compared with pure UHMWPE even at very low concentrations (e.g. 0.4 wt%). The effect of ionic liquids on the elongation-to-break ratio of this nanocomposite system was investigated. The ionic liquid with hexafluorophosphate as the anion was more efficient to increase the toughness of UHMWPE due to the improved compatibility of IL with UHMWPE in the polymer matrix than that of the bromide. The rheological behavior of molten nanocomposites revealed that the storage modulus and the complex viscosity decreased with increasing ionic liquid content in the high frequency region. However, a reverse trend was observed when the frequency was less than 0.05 s−1. In-situ monitoring in the change of crystallinity of the nanocomposite during tensile deformation suggested a mechanism of sliding between UHMWPE crystal regions and the surface of carbon nanofibers. 相似文献
34.
Rui Yang Katherine B. AubrechtHongyang Ma Ran WangRobert B. Grubbs Benjamin S. Hsiao Benjamin Chu 《Polymer》2014
Oxidized cellulose nanofibers (CNF), embedded in an electrospun polyacrylonitrile (PAN) nanofibrous scaffold, were grafted with cysteine to increase the adsorption capability for chromium (VI) and lead (II). Thiol-modified cellulose nanofibers (m-CNF) were characterized by titration, FT-IR, energy dispersive spectroscopy (EDS) and SEM techniques. Static and dynamic Cr(VI) and Pb(II) adsorption studies of m-CNF nanofibrous composite membranes were carried out as a function of pH and of contact time. The results indicated these membranes exhibited high adsorption capacities for both Cr(VI) (87.5 mg/g) and Pb(II) (137.7 mg/g) due to the large surface area and high concentration of thiol groups (0.9 mmol of –SH/gram m-CNF). The morphology and property of m-CNF nanofibrous composite membranes was found to be stable, and they could be used and regenerated multiple times with high recovery efficiency. 相似文献
35.
A series of aromatic polyimides with pendent triphenylamine group were synthesized from equimolar mixtures of 4,4′-oxydianiline (ODA) and 4-(3,5-diaminobenzamido)triphenylamine (4), 4-(3,5-diaminobenzamido)-4′,4″-di-tert-butyltriphenylamine (t-Bu-4) or 4-(3,5-diaminobenzamido)-4′,4″-dimethoxytriphenylamine (MeO-4) with two aromatic tetracarboxylic dianhydrides (DSDA or 6FDA) via a conventional two-step procedure that included a ring-opening polyaddition to give poly(amic acid)s, followed by chemical imidization. These polyimides exhibited good solubility in polar organic solvents and could be solution-cast into flexible and strong films. They showed excellent thermal stability, with Tg values in the range of 284–309 °C. The polyimides derived from diamines t-Bu-4 and MeO-4 exhibited reversible electrochemical oxidation, accompanied by strong color changes with high contrast ratio and electrochromic stability. For the polyimides derived from diamine 4, the coupling reaction between the triphenylamine radical cations occurred during the oxidative process forming a tetraphenylbenzidine structure, which resulted in an additional oxidation state and color change together with enhanced near-IR absorption at fully oxidized state. 相似文献
36.
Electrochemical Performance of PrBaCo2O5+δ and Sm0.5Sr0.5CoO3−δ Infiltrated Ce0.9Gd0.1O1.95 Cathodes
Cathodes with PrBaCo2O5+δ (PBC) and Sm0.5Sr0.5CoO3−δ (SSC) infiltrated on Ce0.9Gd0.1O1.95 (CGO) backbones are prepared using metal nitrates as precursors and ethanol as wetting agent. Electrochemical impedance spectra (EIS) are measured from cathode/CGO/cathode symmetrical cells in 400–650 °C under humidified air. The results indicate that interfacial area specific resistance (ASR) value decreases and then increases with infiltrate loading and minimum values occur at 50 wt.% loading (relative to sum of infiltrate and backbone) for both PBC and SSC infiltrates. ASR values of PBC infiltrated cathodes are lower than that of corresponding SSC infiltrated cathodes in general, and in particular ASR values as low as 1.36 × 10−2 and 2.27 × 10−2 Ω cm2 are obtained at 650 °C in air for 50 wt.% PBC and 50 wt.% SSC infiltrated cathodes, respectively. Conductivity values of CGO electrolyte increase with infiltrate loading and agree with the reported values when the loading reaches 50 wt.%. 相似文献
37.
Hsiang-Hao Chuang Yen-Yi Zhen Yu-Chen Tsai Cheng-Hao Chuang Michael Hsiao Ming-Shyan Huang Chih-Jen Yang 《International journal of molecular sciences》2022,23(3)
Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, is overexpressed and activated in many cancer types. FAK regulates diverse cellular processes, including growth factor signaling, cell cycle progression, cell survival, cell motility, angiogenesis, and the establishment of immunosuppressive tumor microenvironments through kinase-dependent and kinase-independent scaffolding functions in the cytoplasm and nucleus. Mounting evidence has indicated that targeting FAK, either alone or in combination with other agents, may represent a promising therapeutic strategy for various cancers. In this review, we summarize the mechanisms underlying FAK-mediated signaling networks during tumor development. We also summarize the recent progress of FAK-targeted small-molecule compounds for anticancer activity from preclinical and clinical evidence. 相似文献
38.
Jia‐Wei Li Yu‐Jing Chiu Chia‐Jui Chang Hung‐Chieh He Yi‐Hsuan Tu Kuan‐Ting Lin Yu‐Liang Lin Tzu‐Hsun Kao Hsun‐Hao Hsu Hsiao‐Fan Tseng Tien‐Chang Lu Jiun‐Tai Chen 《大分子材料与工程》2020,305(1)
Polyimides (PIs) possess excellent mechanical properties, thermal stability, and chemical resistance and can be converted to carbon materials by thermal carbonization. The preparation of carbon nanomaterials by carbonizing PI‐based nanomaterials, however, has been less studied. In this work, the fabrication of PI nanofibers is investigated using electrospinning and their transformation to carbon nanofibers. Poly(amic acid) carboxylate salts (PAASs) solutions are first electrospun to form PAAS nanofibers. After the imidization and carbonization processes, PI and carbon nanofibers can then be obtained, respectively. The Raman spectra reveal that the carbon nanofibers are partially graphitized by the carbonization process. The diameters of the PI nanofibers are observed to be smaller than those of the PAAS nanofibers because of the formation of the more densely packed structures after the imidization processes; the diameters of the carbon nanofibers remain similar to those of the PI nanofibers after the carbonization process. The thermal dissipation behaviors of the PI and carbon nanofibers are also examined. The infrared images indicate that the transfer rates of thermal energy for the carbon nanofibers are higher than those for the PI nanofibers, due to the better thermal conductivity of carbon caused by the covalent sp2 bonding between carbon atoms. 相似文献
39.
Chia En Liu Wen Chieh Lan Hao Ting Yu Han Lin Yang I. Tseng Liu Hsiao Ping Hsu Chung Wen Lan 《International Journal of Applied Ceramic Technology》2020,17(1):146-152
Silicon kerf loss during wafer slicing and the broken quartz crucibles after silicon casting are two major solid wastes from photovoltaic (PV) industry. Especially, the recycle of kerf-loss silicon has become an urgent issue because near 100 000 t of solid wastes are generated every year. One of the most meaningful recycle routes of the kerf-loss silicon is to make silicon nitride crucibles to replace the quartz crucibles. In this study, we demonstrated how this is feasible through acid leaching refining, slip casting, and nitridation. The reaction-bonded silicon nitride (RBSN) crucibles after oxidation were found pure enough for silicon ingot growth. More importantly, they could be reused after ingot growth. With the present examples, the potential of using the kerf-loss silicon for fine ceramics is prominent. 相似文献
40.