全文获取类型
收费全文 | 105783篇 |
免费 | 7886篇 |
国内免费 | 3207篇 |
专业分类
电工技术 | 4580篇 |
技术理论 | 4篇 |
综合类 | 4380篇 |
化学工业 | 19350篇 |
金属工艺 | 5418篇 |
机械仪表 | 7012篇 |
建筑科学 | 5596篇 |
矿业工程 | 1338篇 |
能源动力 | 3640篇 |
轻工业 | 7892篇 |
水利工程 | 1460篇 |
石油天然气 | 2728篇 |
武器工业 | 486篇 |
无线电 | 14893篇 |
一般工业技术 | 17487篇 |
冶金工业 | 6296篇 |
原子能技术 | 1383篇 |
自动化技术 | 12933篇 |
出版年
2024年 | 283篇 |
2023年 | 1372篇 |
2022年 | 2476篇 |
2021年 | 3688篇 |
2020年 | 2667篇 |
2019年 | 2564篇 |
2018年 | 2901篇 |
2017年 | 3069篇 |
2016年 | 3408篇 |
2015年 | 3579篇 |
2014年 | 4859篇 |
2013年 | 6391篇 |
2012年 | 6861篇 |
2011年 | 7882篇 |
2010年 | 6462篇 |
2009年 | 6259篇 |
2008年 | 6169篇 |
2007年 | 5346篇 |
2006年 | 5198篇 |
2005年 | 4467篇 |
2004年 | 3580篇 |
2003年 | 3428篇 |
2002年 | 3541篇 |
2001年 | 2980篇 |
2000年 | 2487篇 |
1999年 | 2206篇 |
1998年 | 2602篇 |
1997年 | 1856篇 |
1996年 | 1590篇 |
1995年 | 1245篇 |
1994年 | 1047篇 |
1993年 | 843篇 |
1992年 | 611篇 |
1991年 | 530篇 |
1990年 | 447篇 |
1989年 | 387篇 |
1988年 | 338篇 |
1987年 | 242篇 |
1986年 | 178篇 |
1985年 | 150篇 |
1984年 | 122篇 |
1983年 | 78篇 |
1982年 | 62篇 |
1981年 | 62篇 |
1980年 | 47篇 |
1979年 | 40篇 |
1978年 | 33篇 |
1977年 | 39篇 |
1976年 | 72篇 |
1975年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
Linlin Zhu Liyuan Zhang Xi Li Xiaoqi Jin Tiejun Shi 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(7):551-560
AbstractGraphene oxide (GO) was functionalized by polyether amine (PEA) via two methods which were one-pot modification in acetone (GON) and two steps with the intermediate product of GOCO-Cl generated (GONS). There were more PEA successfully grafted onto GO for GONS than GON. The onset polymerization temperatures of the benzoxazine (Bz) composites decreased by the inclusion of 1?wt% of GO, GON or GONS. Thermal stability of the polybenzoxazine (PBz) composites was significantly improved indicated from the increase of weight loss temperature. T10, T20 and T50 values of the composites with GONS were higher than that of the others. Toughness of PBzs may be enhanced by the incorporation of nanofillers, and GONS had stronger interfacial interaction with PBz matrix than GON. 相似文献
103.
Seong‐Hee Kim 《Quality and Reliability Engineering International》2015,31(6):923-934
We present a distribution‐free tabular cumulative sum chart for monitoring the variability of an autocorrelated process. A quantity known as the asymptotic variance parameter is employed as a measure of the variability, and a distribution‐free tabular cumulative sum chart is applied to variance estimates calculated from batches of nonoverlapping samples. The proposed chart is applicable to a stationary process with a general marginal distribution and a general autocorrelation structure. It also determines control limits analytically without trial‐and‐error simulations. The performance of the proposed chart is tested on stationary processes with both normal and nonnormal marginals with various autocorrelation structures. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
104.
Natural Computing - The fiber stretching process plays the key role in the process of fiber production and its effects is measured by the stretching ratio. The stretching ratio is determined by the... 相似文献
105.
106.
Oh Seung-Jun Yoon Jeong-Hwan Kim Si-Pom 《Journal of Mechanical Science and Technology》2021,35(3):1065-1073
Journal of Mechanical Science and Technology - In the industry, globe valves, which are commonly used to precise control the flow rate along with opening and closing flow in pipes, are technically... 相似文献
107.
二氧化碳制冷技术和提升氨制冷安全体系是绿色制冷的重要支撑,北京冬奥会大量采用绿色制冷技术,不仅推动国内制冷行业可持续发展,而且将对2030年碳达峰和2060年碳中和产生深远影响. 相似文献
108.
Ha-Nul Lee Joo-Hee Choi Ji-Yeon Park Jae-Hun Ahn Da Eun Jang Jae Gun Shim Jong-Hwan Park Young-Min Kim 《Food science and biotechnology》2021,30(4):583
Vegetable soup (VS), a plant-based functional food, has been used as a traditional folk medicine and is attracting attention for its ability to enhance the immune response. β-Glucan, a well-established and effective immunomodulator, has synergistic effects when used in combination with some bioactive compounds. In the present study, we aimed to evaluate the synergistic immunomodulatory effects of the combination of VS and β-glucan on macrophage-mediated immune responses. β-Glucan was demonstrated to synergistically enhance the VS-stimulated immune response, including the production of interleukin-6, tumor necrosis factor-α, and nitric oxide, mainly through the mitogen-activated protein kinase pathway in macrophages. In addition, this combination has the potential for further development in functional foods with immune-enhancing activity.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10068-021-00888-x. 相似文献
109.
Food Science and Biotechnology - St. Paul’s Wort (Siegesbeckia orientalis L.) confers anti-oxidative, anti-inflammatory, anti-allergic, anti-infertility, and immunosuppressive properties.... 相似文献
110.
S H Lee J H Ko J R Kim Y J Kim J J Lee C W Kim T H Lee 《Water science and technology》2006,53(4-5):115-123
The adverse effect of nitrate on the phosphate release rate in the anaerobic phase was observed and was hardly explainable with conventional EBPR process models. Four possible mechanisms were proposed including substrate competition, reduced fermentation, parallel reaction and sequential reaction. Batch experiments were designed and conducted to identify the dominant mechanism. Results showed that the sequential reaction was the only possible mechanism where only denitrification occurred if any nitrate existed in the anaerobic phase. Then the phosphate release following after the nitrate was completely removed. Nitrate inhibition effect was added into the PHA storage rate to incorporate the sequential reaction in the conventional ASM3 plus EAWAG bio-P module (ASM3 + P). Nitrate inhibition coefficient, K(I,NO,PAO) was found to be as low as 0.05 mg/L. This correlated well with experimental observation where no also meant that the anaerobic compartment of a continuous flow reactor could be seriously affected by the residual nitrate contained in the sludge recycle flow. This phenomenon caused overestimation of the phosphate uptake rate and consequently underestimation of PO4(3-) -P concentration. This problem was resolved by incorporation of a nitrate inhibition term in the ASM3 + P for more accurate simulation of the EBPR process. 相似文献