全文获取类型
收费全文 | 52818篇 |
免费 | 4189篇 |
国内免费 | 1995篇 |
专业分类
电工技术 | 2748篇 |
技术理论 | 5篇 |
综合类 | 2985篇 |
化学工业 | 8962篇 |
金属工艺 | 3179篇 |
机械仪表 | 3233篇 |
建筑科学 | 3758篇 |
矿业工程 | 1729篇 |
能源动力 | 1682篇 |
轻工业 | 3749篇 |
水利工程 | 858篇 |
石油天然气 | 3758篇 |
武器工业 | 396篇 |
无线电 | 5742篇 |
一般工业技术 | 6344篇 |
冶金工业 | 2937篇 |
原子能技术 | 651篇 |
自动化技术 | 6286篇 |
出版年
2024年 | 108篇 |
2023年 | 851篇 |
2022年 | 1294篇 |
2021年 | 2164篇 |
2020年 | 1652篇 |
2019年 | 1421篇 |
2018年 | 1627篇 |
2017年 | 1761篇 |
2016年 | 1578篇 |
2015年 | 2081篇 |
2014年 | 2685篇 |
2013年 | 3108篇 |
2012年 | 3321篇 |
2011年 | 3622篇 |
2010年 | 3204篇 |
2009年 | 2875篇 |
2008年 | 2819篇 |
2007年 | 2738篇 |
2006年 | 2895篇 |
2005年 | 2475篇 |
2004年 | 1549篇 |
2003年 | 1352篇 |
2002年 | 1265篇 |
2001年 | 997篇 |
2000年 | 1179篇 |
1999年 | 1462篇 |
1998年 | 1165篇 |
1997年 | 993篇 |
1996年 | 993篇 |
1995年 | 874篇 |
1994年 | 700篇 |
1993年 | 456篇 |
1992年 | 370篇 |
1991年 | 290篇 |
1990年 | 235篇 |
1989年 | 196篇 |
1988年 | 173篇 |
1987年 | 105篇 |
1986年 | 88篇 |
1985年 | 59篇 |
1984年 | 52篇 |
1983年 | 36篇 |
1982年 | 32篇 |
1981年 | 29篇 |
1980年 | 17篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1975年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
11.
12.
13.
14.
Xuejie Li Yaqing Wen Jian Zhang Dongyun Ma Jie Zhang Yanxia An Xiaoyan Song Xiujuan Ren Weifeng Zhang 《International Journal of Food Science & Technology》2022,57(3):1544-1553
The effects of non-thermal plasma (NTP) on the physicochemical properties of wheat flour and the quality of fresh wet noodles ( FWN) were investigated. The results showed that NTP effectively decreased the total plate count (TPC), yeast and mould count (YMC) and Bacillus spp. in wheat flour. Wet gluten contents and the stability time reached the maximum when treated for 20 s. The viscosity of starch increased significantly after treatment due to the increased of damaged starch. The contents of secondary structure were altered to some extent, which was because that the ordered network structure of gluten protein broken. Furthermore, compared with the control, texture properties of FWN were enhanced significantly at 20 s, and the darkening rate of FWN was greatly inhibited due to the low polyphenol oxidase (PPO) activity. Consequently, the most suitable treatment was 500 W for 20 s, providing a basis for the application of NTP in flour products. 相似文献
15.
Qing Li Jun Wang Jie Ma Meng Ni Fan Yang Peng Liu Kuo Yang Lee Hsing-I Hsiang Deyuan Shen Dingyuan Tang 《Journal of the American Ceramic Society》2022,105(5):3375-3381
High-efficiency Yb:Y2O3 laser ceramics were fabricated using the vacuum-sintering plus hot isostatic pressing (HIP) without sintering additives. High-purity well-dispersed nanocrystalline Yb:Y2O3 powder was synthesized using a modified co-precipitation method in-house. The green bodies were first vacuum sintered at a temperature as low as 1430°C and then HIPed at 1450°C. Finally, the samples were air annealed at 800°C for 10 h. Although no sintering aids were used, full density of the samples with excellent optical homogeneity and an inline transmission of 80% at 400 nm could be obtained. Moreover, photodarkening phenomenon was not detected in the ceramics. Preliminary laser experiment with the fabricated ceramics in a two-mirror cavity has demonstrated 32 W continuous-wave (CW) output at ∼1077 nm with an optical-to-optical conversion efficiency of 58.2%. To the best of our knowledge, this is so far the highest CW output power and optical-to-optical conversion efficiency achieved with the Yb3+-doped sesquioxide ceramics in a simple two-mirror cavity. 相似文献
16.
17.
Engineering with Computers - To increase the efficiency and accuracy in slope stability analysis, a reliability analysis method based on machine learning and the advanced first-order second-moment... 相似文献
18.
Suisui Zhang Jingying Li Yan Nie Luyao Qiang Boyang Bai Zhiwei Peng Xiaoxun Ma 《中国化学工程学报》2022,42(2):236-244
HFC-134a is a widely used environment-friendly refrigerant. At present, China is the largest producer of HFC-134a in the world. The production of HFC-134a in China mainly adopts the calcium carbide acetylene route. However, the production route has high resource and energy consumption and large waste emission, and few of the studies addressed on the environmental performance of its production process. This study quantified the environmental performance of HFC-134a production by calcium carbide route via carrying out a life cycle assessment (LCA) using the CML 2001 method. And uncertainty analysis by Monte-Carlo simulation was also carried out. The results showed that electricity had the most impact on the environment, followed by steam, hydrogen fluoride and chlorine, and the impact of direct CO2 emissions in calcium carbide production stage on the global warming effect also could not be ignored. Therefore, the clean energy (e.g., wind, solar, biomass, and natural gas) was used to replace coal-based electricity and coal-fired steam in this study, showing considerable environmental benefits. At the same time, the use of advanced production technologies could also improve environmental benefits, and the environmental impact of the global warming category could be reduced by 4.1% via using CO2 capture and purification technology. The Chinese database of HFC-134a production established in this study provides convenience for the relevant study of scholars. For the production of HFC-134a, this study helps to better identify the specific environmental hotspots and proposes useful ways to improve the environmental benefits. 相似文献
19.
Vilde Yuli Stenberg Roy Hartvig Larsen Li-Wei Ma Qian Peng Petras Juzenas
yvind Sverre Bruland Asta Juzeniene 《International journal of molecular sciences》2021,22(9)
Radioligand therapy targeting the prostate-specific membrane antigen (PSMA) is rapidly evolving as a promising treatment for metastatic castration-resistant prostate cancer. The PSMA-targeting ligand p-SCN-Bn-TCMC-PSMA (NG001) labelled with 212Pb efficiently targets PSMA-positive cells in vitro and in vivo. The aim of this preclinical study was to evaluate the therapeutic potential of 212Pb-NG001 in multicellular tumour spheroid and mouse models of prostate cancer. The cytotoxic effect of 212Pb-NG001 was tested in human prostate C4-2 spheroids. Biodistribution at various time points and therapeutic effects of different activities of the radioligand were investigated in male athymic nude mice bearing C4-2 tumours, while long-term toxicity was studied in immunocompetent BALB/c mice. The radioligand induced a selective cytotoxic effect in spheroids at activity concentrations of 3–10 kBq/mL. In mice, the radioligand accumulated rapidly in tumours and was retained over 24 h, while it rapidly cleared from nontargeted tissues. Treatment with 0.25, 0.30 or 0.40 MBq of 212Pb-NG001 significantly inhibited tumour growth and improved median survival with therapeutic indexes of 1.5, 2.3 and 2.7, respectively. In BALB/c mice, no signs of long-term radiation toxicity were observed at activities of 0.05 and 0.33 MBq. The obtained results warrant clinical studies to evaluate the biodistribution, therapeutic efficacy and toxicity of 212Pb-NG001. 相似文献
20.