全文获取类型
收费全文 | 1085篇 |
免费 | 81篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 24篇 |
综合类 | 11篇 |
化学工业 | 293篇 |
金属工艺 | 21篇 |
机械仪表 | 33篇 |
建筑科学 | 41篇 |
矿业工程 | 5篇 |
能源动力 | 53篇 |
轻工业 | 58篇 |
水利工程 | 11篇 |
石油天然气 | 23篇 |
武器工业 | 13篇 |
无线电 | 136篇 |
一般工业技术 | 212篇 |
冶金工业 | 47篇 |
原子能技术 | 4篇 |
自动化技术 | 191篇 |
出版年
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 41篇 |
2021年 | 49篇 |
2020年 | 58篇 |
2019年 | 70篇 |
2018年 | 64篇 |
2017年 | 59篇 |
2016年 | 60篇 |
2015年 | 44篇 |
2014年 | 38篇 |
2013年 | 76篇 |
2012年 | 61篇 |
2011年 | 67篇 |
2010年 | 50篇 |
2009年 | 47篇 |
2008年 | 30篇 |
2007年 | 48篇 |
2006年 | 34篇 |
2005年 | 24篇 |
2004年 | 20篇 |
2003年 | 23篇 |
2002年 | 20篇 |
2001年 | 16篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 16篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 13篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1176条查询结果,搜索用时 46 毫秒
51.
采用环氧大豆油(ESO)作为无溶剂环氧地坪涂料体系的活性稀释剂成分,对环氧地坪涂料进行共混改性,研究了ESO用量对环氧地坪涂料的稀释作用和增塑作用,及其对环氧地坪体系性能的影响,确定ESO在环氧地坪涂料体系中的合适用量;并通过对固化剂和促进剂的选择和评估,确定合适的固化体系。 相似文献
52.
Ngoc Tuan Nguyen Wei-Hsin Sun Tzu-Hsuan Chen Po-Chun Tsai Chih-Chen Chen Shir-Ly Huang 《International journal of molecular sciences》2022,23(7)
Rheumatoid arthritis (RA), an autoimmune disease, is characterized by chronic joint inflammation and pain. We previously found that the deletion of T-cell death-associated gene 8 (TDAG8) significantly reduces disease severity and pain in RA mice. Whether it is by modulating gut microbiota remains unclear. In this study, 64 intestinal samples of feces, cecal content, and cecal mucus from the complete Freund’s adjuvant-induced arthritis mouse models were compared. The α- and β-diversity indices of the microbiome were significantly lower in RA mice. Cecal mucus showed a higher ratio of Firmicutes to Bacteroidetes in RA than healthy mice, suggesting the ratio could serve as an RA indicator. Four core genera, Eubacterium_Ventriosum, Alloprevotella, Rikenella, and Treponema, were reduced in content in both feces and mucus RA samples, and could serve microbial markers representing RA progression. TDAG8 deficiency decreased the abundance of proinflammation-related Eubacterium_Xylanophilum, Clostridia, Ruminococcus, Paraprevotella, and Rikenellaceae, which reduced local mucosal inflammation to relieve RA disease severity and pain. The pharmacological block of the TDAG8 function by a salicylanilide derivative partly restored the RA microbiome to a healthy composition. These findings provide a further understanding of specific bacteria interactions with host gut mucus in the RA model. The modulation by TDAG8 on particular bacteria can facilitate microbiota-based therapy. 相似文献
53.
Tanveer Ahmed Khan Munirah Ezzah Tuan Zakaria Hyun-Joong Kim Suriati Ghazali Saidatul Shima Jamari 《应用聚合物科学杂志》2020,137(8):48396
Recently, the use of controlled release fertilizers in agriculture has resulted in huge benefits in plant growth and cultivation. Superabsorbent polymer (SAP)-coated fertilizers have the added advantage in retaining water in soil after irrigation and also reduce the nutrient release rate from soil in a controlled manner. This study aimed to produce a nitrogen–phosphorus–potassium (NPK) fertilizer coated with superabsorbent carbonaceous microspheres polymer (SPC) by inverse suspension polymerization method with water-retention and controlled release properties. Two sets of experiments were conducted: (1) three different weight percentages and (2) different materials. NPK coated with SPC showed increasing water-retention ability with respect to carbon microsphere percentages and retains >80% water at the 30th day of experiment compared with pure NPK and NPK coated with SAP. The slow release behavior of all samples was investigated by induced coupled plasma mass spectrometry spectrometry and results showed that NPK coated with SAP and SPC has a low release rate with <50% nutrient release compared with uncoated NPK at the 30th day. The release mechanism kinetics of NPK coated with SAP and SPC were studied based on the Kosmeyer–Peppas model. The mechanisms approached Fickian diffusion-controlled release as the n value for both samples was less than 0.5. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48396. 相似文献
54.
Thien Vuong Nguyen Phi Hung Dao Tuan Anh Nguyen Viet Hung Dang Minh Nguyet Ha Thi Thuy Trang Nguyen Quoc Trung Vu Ngọc Linh Nguyen Tran Chien Dang Phuong Nguyen-Tri Dai Lam Tran Le Trong Lu 《应用聚合物科学杂志》2020,137(37):49116
This work aims to clarify the photocatalytic degradation mechanism and heat reflectance recovery performance of waterborne acrylic polymer/ZnO nanocomposite coating. To fabricate the nanocomposite coating, ZnO nanoparticles (nano-ZnO) were dispersed into acrylic polymer matrix at the various concentrations from 1 to 6% (by total weight of resin solids). The photocatalytic degradation of nanocomposite coating under ultraviolet (UV) light irradiation has been investigated by monitoring its weight loss and chemical/microstructural/morphological changes. As the topcoat layer, its heat reflectance recovery has been evaluated under UV/condensation exposure by using an artificial dirty mixture of 85 wt% nanoclay, 10 wt% silica particles (1–5 μm), 1 wt% carbon black, and 2 wt% engine oil. After 108-cycle UV/condensation exposure, infrared spectra and weight loss analysis indicated that the maximal degradation for nanocomposite coating is observed at 1 wt% nano-ZnO. On the other hand, after 96 hr of UV light exposure, the nanocomposite coating with1 wt% nano-ZnO could restore effectively the reflective index of solar-heat reflectance coating (from 58.45 to 80.78%). Finally, the photodegradation mechanism of this waterborne acrylic polymer coating has been proposed as the UV-induced formation of CC CO conjugated double bonds. As a result, its self-cleaning phenomenon can be achieved as the recovery of heat reflectance. 相似文献
55.
Toan Dinh Van Dau Canh‐Dung Tran Tuan‐Khoa Nguyen Hoang‐Phuong Phan Nam‐Trung Nguyen Dzung Viet Dao 《大分子材料与工程》2019,304(6)
Flexible multifunctional electronic devices are of high interest for a wide range of applications including thermal therapy and respiratory devices in medical treatment, safety equipment, and structural health monitoring systems. This paper reports a scalable and efficient strategy of manufacturing a polyacrylonitrile‐carbon nanotube‐polyacrylonitrile (PAN‐CNT‐PAN) robust flexible platform for multifunctional electronic devices including flexible heaters, temperature sensors, and flexible thermal flow sensors. The key advantages of this platform include low cost, porosity, mechanical robustness, and electrical stability under mechanical bending, enabling the development of fast‐response flexible heaters with a response time of ≈1.5 s and relaxation time of ≈1.7 s. The temperature‐sensing functionality is also investigated with a range of temperature coefficient of resistances from ?650 to ?900 ppm K?1. A flexible hot‐film sensing concept is successfully demonstrated using PAN‐CNT‐PAN with a high sensitivity of 340 mV (m s?1)?1. The sensitivity enhancement of 50% W?1 is also observed with increasing supply power. The low cost, porosity, versatile, and robust properties of the proposed platform will enable the development of multifunctional electronic devices for numerous applications such as flexible thermal management, temperature stabilization in industrial processing, temperature sensing, and flexible/wearable devices for human healthcare applications. 相似文献
56.
57.
Anna Haliaková Anna Prnová Róbert Klement Dušan Galusek Wei-Hsing Tuan 《Ceramics International》2012,38(7):5543-5549
The paper deals with the synthesis and characterisation of binary aluminate glasses in the La2O3–Al2O3 system with Al2O3 contents changing between 74.6 and 86.9 mol% (48–65 wt.%), and of ternary glasses with 75.7 mol% Al2O3 doped with 1 mol% of Nd2O3 or Er2O3. Six binary and two ternary compositions were prepared. Flame synthesis facilitated the preparation of X-ray amorphous microspheres in the systems with 58 wt.% Al2O3, and with eutectic composition in the pseudobinary LaAlO3–LaAl11O18 system doped with Er. Other systems contained low fractions of crystalline LaAlO3 perovskite, regardless of the composition. The diameter of prepared microspheres ranged between 2 and 10 μm. They were transparent for visible light, as well as in the IR wavenumber range from 1300 to 4000 cm?1. 相似文献
58.
Sai Wang Bang‐Ke Luo Ying‐Jun Qin Lin‐Hui Su Simon D. Stewart Tuan‐Tuan Wang Jin‐Peng Tang Bai‐Dong He Jin‐Hua Zhang Hsing‐Juh Lin Yang Yang 《河流研究与利用》2020,36(7):1124-1136
Understanding the trophic discrimination (?13C and ?15N) between consumers and diets in fluvial systems remains difficult because of the variable food sources and complex predator–prey interactions from headwaters to the estuaries. Here, stable carbon (δ13C) and nitrogen (δ15N) isotopes in fish and invertebrates from a large subtropical river in southern China were determined to explore trophic discrimination in conjunction with a gut content analysis. The ?13C values showed significant differences (p < .05) among functional feeding groups, with fish, shrimp, and insect scrapers presenting higher ?13C values (1.20 ± 0.23‰ to 1.51 ± 0.31‰) than other groups. The ?15N values varied significantly between invertebrates (0.64 ± 0.17‰ of insect collector‐gatherers to 1.63 ± 0.36‰ of shrimp predators) and fish (1.98 ± 0.19‰ of detritivores to 2.71 ± 0.43‰ of crustaceavores) and exhibited an increasing tendency from primary to secondary consumers. A linear regression analysis revealed that the longitudinal changes in ?13C and ?15N were closely associated with the δ13C of periphyton, the δ15N of particulate organic matter (POM) in water, and the relative contribution (%) of periphyton and organic detritus to the diet composition of consumers. These results indicated that discrimination factors might not only be influenced by the isotope signatures of basal food sources but also downstream shifts in dominant food items utilized by consumers. In particular, trophic discrimination between periphyton– and detritus–based food chains, such as “epilithic diatoms–shrimp scrapers–crustaceavorous fish” and “POM–bivalves–molluscivorous fish,” displayed regionally specific patterns. When back‐calculating to the diet assimilation and trophic position in subtropical streams and rivers, we suggest using the basin‐scale ?13C value of 0.96 ± 0.26‰ for all consumers and ?15N values of 1.07 ± 0.32‰ for invertebrates and 2.38 ± 0.37‰ for fish. 相似文献
59.
60.