全文获取类型
收费全文 | 2160篇 |
免费 | 63篇 |
国内免费 | 7篇 |
学科分类
工业技术 | 2230篇 |
出版年
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 35篇 |
2020年 | 23篇 |
2019年 | 27篇 |
2018年 | 34篇 |
2017年 | 28篇 |
2016年 | 48篇 |
2015年 | 35篇 |
2014年 | 73篇 |
2013年 | 194篇 |
2012年 | 127篇 |
2011年 | 136篇 |
2010年 | 104篇 |
2009年 | 108篇 |
2008年 | 141篇 |
2007年 | 90篇 |
2006年 | 85篇 |
2005年 | 82篇 |
2004年 | 77篇 |
2003年 | 72篇 |
2002年 | 59篇 |
2001年 | 55篇 |
2000年 | 44篇 |
1999年 | 56篇 |
1998年 | 79篇 |
1997年 | 57篇 |
1996年 | 65篇 |
1995年 | 34篇 |
1994年 | 36篇 |
1993年 | 28篇 |
1992年 | 21篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有2230条查询结果,搜索用时 15 毫秒
41.
Detection of viable antibiotic‐resistant/sensitive Acinetobacter baumannii in indoor air by propidium monoazide quantitative polymerase chain reaction 下载免费PDF全文
C.‐C. Tseng P.‐K. Hsiao K.‐C. Chang C.‐C. Cheng L.‐M. Yiin C.‐J. Hsieh 《Indoor air》2015,25(5):475-487
Acinetobacter baumannii represents a significant cause of nosocomial infections. Therefore, we combined real‐time quantitative polymerase chain reaction (PCR) with the propidium monoazide (PMA‐qPCR) to assess the feasibility of detecting viable, airborne A. baumannii. The biological collection efficiencies of three samplers for collecting airborne A. baumannii were evaluated by PMA‐qPCR in a chamber study. After sampling, the effects of storage in collection fluid on A. baumannii were evaluated. The results showed that the culturable ratio of A. baumannii measured using the culture method was significantly correlated with the viable ratio measured using PMA‐qPCR, but was not significantly correlated with the qPCR results. It was indicated that the AGI‐30 impinger and the BioSampler were much more effective than the Nuclepore filter sampler for collecting airborne A. baumannii. The storage temperature was critical for aerosol samples, as the loss of viable A. baumannii was minimized when the PMA‐bound DNA was stored at ?20°C or if the collected cells were stored at 4°C and subsequently processed by PMA‐qPCR within 1 month. The PMA‐qPCR method was also to distinguish between colistin‐sensitive and colistin‐resistant A. baumannii, and no colistin‐sensitive A. baumannii was detected by PMA‐qPCR upon treatment of the BioSampler collection medium with 2 μg/ml colistin for 5 min. 相似文献
42.
β-Ga2O3 nanobelts were synthesized using a vapor transport process in a controlled ambient. Structural characterization revealed that the as-synthesized samples consisted of monoclinic β-Ga2O3 nanobelts, and the presence of gallium-associated defects was verified using cathodoluminescence (CL). The formation of gallium-associated defects was explained by the insufficiency of the supply of cations, generating gallium vacancies on the (010) facet during growth. Furthermore, field-emission measurements indicated that β-Ga2O3 nanobelts exhibited defect-related electron emission. The turn-on fields of β-Ga2O3 nanobelts increased significantly with the degree of structural defects. For a sample prepared under 15% ambient oxygen, Fowler–Nordheim (F–N) analysis revealed two distinct field-enhancement factors of 1194 and 276, respectively. A correlation between field emission and structural defects was proposed. The experimental results demonstrate the presence of gallium-associated defects, which behave as electron traps, degrading the electron field-emission properties of β-Ga2O3 nanobelts. 相似文献
43.
Theodore T. Allen Shih‐Hsien Tseng 《Quality and Reliability Engineering International》2011,27(8):1199-1210
This paper explores the issue of model misspecification, or bias, in the context of response surface design problems involving quantitative and qualitative factors. New designs are proposed specifically to address bias and compared with five types of alternatives ranging from types of composite to D‐optimal designs using four criteria including D‐efficiency and measured accuracy on test problems. Findings include that certain designs from the literature are expected to cause prediction errors that practitioners would likely find unacceptable. A case study relating to the selection of science, technology, engineering, or mathematics majors by college students confirms that the expected substantial improvements in prediction accuracy using the proposed designs can be realized in relevant situations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
44.
Yu-Chun Chen Ting-Chang Chang Hung-Wei Li Shih-Cheng Chen Wan-Fang Chung Yi-Hsien Chen Ya-Hsiang Tai Tseung-Yuen Tseng Fon-Shan Yeh 《Thin solid films》2011,520(5):1432
This paper investigates the origin of the bias stability under ambient gas (oxygen, moisture and vacuum) of In–Ga–Zn–O thin film transistors with different annealing temperatures. In Zn-based TFTs, the electrical characteristic of device is a strongly function with the ambient gas, the simultaneous gas ambient and bias stresses are applied on devices annealed in atmosphere ambient to study this issue. The result shows the device which is annealed at temperature up to 330 °C has worst reliability. We suppose that the sensitivity of gas ambient depend the defect state, which is associated to the annealing temperature, of surface in a-IGZO. 相似文献
45.
Supramolecular Nanosubstrate‐Mediated Delivery for Reprogramming and Transdifferentiation of Mammalian Cells 下载免费PDF全文
46.
Self‐Crack‐Filled Graphene Films by Metallic Nanoparticles for High‐Performance Graphene Heterojunction Solar Cells 下载免费PDF全文
47.
Ying-Yu Kuo Wai-Tim Jim Liang-Cheng Su Chi-Jung Chung Ching-Yu Lin Chieh Huo Jen-Chih Tseng Shih-Han Huang Chih-Jen Lai Bo-Chih Chen Bi-Juan Wang Tzu-Min Chan Hui-Ping Lin Wun-Shaing Wayne Chang Chuang-Rung Chang Chih-Pin Chuu 《International journal of molecular sciences》2015,16(5):10748-10766
Head and neck cancers, which affect 650,000 people and cause 350,000 deaths per year, is the sixth leading cancer by cancer incidence and eighth by cancer-related death worldwide. Oral cancer is the most common type of head and neck cancer. More than 90% of oral cancers are oral and oropharyngeal squamous cell carcinoma (OSCC). The overall five-year survival rate of OSCC patients is approximately 63%, which is due to the low response rate to current therapeutic drugs. In this review we discuss the possibility of using caffeic acid phenethyl ester (CAPE) as an alternative treatment for oral cancer. CAPE is a strong antioxidant extracted from honeybee hive propolis. Recent studies indicate that CAPE treatment can effectively suppress the proliferation, survival, and metastasis of oral cancer cells. CAPE treatment inhibits Akt signaling, cell cycle regulatory proteins, NF-κB function, as well as activity of matrix metalloproteinase (MMPs), epidermal growth factor receptor (EGFR), and Cyclooxygenase-2 (COX-2). Therefore, CAPE treatment induces cell cycle arrest and apoptosis in oral cancer cells. According to the evidence that aberrations in the EGFR/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling, NF-κB function, COX-2 activity, and MMPs activity are frequently found in oral cancers, and that the phosphorylation of Akt, EGFR, and COX-2 correlates to oral cancer patient survival and clinical progression, we believe that CAPE treatment will be useful for treatment of advanced oral cancer patients. 相似文献
48.
This note is a corrigendum of the paper ‘Linear Time Varying Model Predictive Control and its Application to Active Steering Systems: Stability Analysis and Experimental Validation’, published on the volume 18, issue 8, pages 862–875 of the International Journal of Robust and Nonlinear Control in 2008. Next we point out a technical error in the proof of Lemma 2 of the paper, and provide the corrected version of the lemma. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
49.
The heat transfer and flow characteristics of a photoelectrochemical (PEC) hydrogen generation reactor are investigated numerically. Four different reactor designs are considered in this study. The solar irradiation is separated into short and long wavelength parts depending on the energy band gap of the photoelectrode used. While short wavelength part is used to generate electron and hole pairs, the long wavelength part is used to heat the system. Because the energy required for splitting water decreases as temperature is increased, heating the reactor by using the long wave energy increases the system efficiency. Thus, how the long wavelength energy is absorbed by the reactor is very important.The results show that more long wavelength energy kept inside the reactor can increase the solar-to-hydrogen efficiency, ηSH. For Fe2O3 photoelectrode, careful reactor design can increase ηSH by 11.0%. For design D under 4000 W/m2 irradiation and a quantum efficiency of 30%, ηSH is found to be 14.1% and the hydrogen volume production rate is 166 L/m2 h for Fe2O3. Effects of several parameters on the PEC hydrogen reactor are also discussed. 相似文献
50.
Wei-Cheng Lin Chun-Nan Chen Tzu-Tsung Tseng Ming-Hsiung Wei J.H. Hsieh Wenjea J. Tseng 《Journal of the European Ceramic Society》2010,30(14):2849-2857
Silver nanoparticles prepared by a reverse micelle process were sequentially deposited on rutile-structured TiO2 particles via an electrostatic layer-by-layer (LbL) deposition together with a hydrophilic/hydrophobic interaction. The TiO2 surface was first mediated by a preferential adsorption of poly(allylamine hydrochloride) (PAH) cationic molecules, before being mixed with the Ag nanoparticles encapsulated in reverse micelles consisting of anionic surfactant of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in isooctane. The deposition of Ag nanoparticles was not of a uniform coverage on the TiO2 surface, but of a heterogeneous growth of the Ag particles on the TiO2 surface. Antibacterial activity of the composites against gram-negative bacteria, i.e., Escherichia coli (E. coli), was found to increase with the deposition cycle, resulted mainly from the increased Ag concentration. The bactericidity is persistent in the absence of ultraviolet (UV) light. Over the concentration range of Ag examined, i.e., Ag/Ti atomic ratio varies from 0.28% to 0.53%, photocatalytic efficiency of the composites against methylene blue (MB) dye in an aqueous solution also improved pronouncedly with the silver concentration under UV exposure. 相似文献