全文获取类型
收费全文 | 185847篇 |
免费 | 15638篇 |
国内免费 | 8396篇 |
学科分类
工业技术 | 209881篇 |
出版年
2024年 | 521篇 |
2023年 | 2814篇 |
2022年 | 4775篇 |
2021年 | 7165篇 |
2020年 | 5486篇 |
2019年 | 4506篇 |
2018年 | 4951篇 |
2017年 | 5662篇 |
2016年 | 5097篇 |
2015年 | 7113篇 |
2014年 | 9424篇 |
2013年 | 11326篇 |
2012年 | 12646篇 |
2011年 | 13676篇 |
2010年 | 12232篇 |
2009年 | 11670篇 |
2008年 | 11378篇 |
2007年 | 10873篇 |
2006年 | 10794篇 |
2005年 | 9028篇 |
2004年 | 6283篇 |
2003年 | 5442篇 |
2002年 | 5190篇 |
2001年 | 4556篇 |
2000年 | 4370篇 |
1999年 | 4349篇 |
1998年 | 3655篇 |
1997年 | 2856篇 |
1996年 | 2605篇 |
1995年 | 2092篇 |
1994年 | 1748篇 |
1993年 | 1235篇 |
1992年 | 969篇 |
1991年 | 776篇 |
1990年 | 558篇 |
1989年 | 502篇 |
1988年 | 391篇 |
1987年 | 232篇 |
1986年 | 202篇 |
1985年 | 125篇 |
1984年 | 106篇 |
1983年 | 79篇 |
1982年 | 77篇 |
1981年 | 72篇 |
1980年 | 69篇 |
1979年 | 41篇 |
1978年 | 15篇 |
1977年 | 34篇 |
1976年 | 18篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Feng Wenran Li Zhen Chen Yingying Chen Jinyang Lang Haoze Wan Jianghong Gao Yan Dong Haitao 《Journal of Materials Science》2022,57(3):1881-1889
Journal of Materials Science - Although chalcogenide materials continue to generate considerable interest due to great potentials for various optoelectronic devices, annealing for a long time in... 相似文献
2.
3.
Kelin Hu Feipeng Wang Yuyang Yan Hongcheng Liu Zijia Shen 《Ceramics International》2021,47(11):15228-15236
In this paper, a novel hybrid structure of Pd doped ZnO/SnO2 heterojunction nanofibers with hexagonal ZnO columns was one step synthesized from electrospun precursor nanofibers. Due to the synergistic effect of hexagonal ZnO, SnO2 and Pd, the structure exhibited excellent hydrogen (H2) gas sensing properties. At low-temperature of 120 °C, the response (Ra/Rg) to 100 ppm H2 gas exceeded 160, the response/recovery time was only 20 s and 6 s respectively and the limit of detection was only 0.5 ppm. Meanwhile, it also had good selectivity for H2 gas and excellent linearity. In addition, the materials were characterized by XRD, FESEM, HRTEM, XPS, and the synthesis mechanism and gas sensing mechanism were proposed. 相似文献
4.
Shanshan Zhuang Wenxiong Zheng Yunong Na Naiyi Chen Fan Gong Bingxuan Huang Stephen Brennan Charles Congyi Liu Jian Cheng Lukai Ma Huifan Liu 《International Journal of Food Science & Technology》2022,57(2):1093-1103
The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results. 相似文献
5.
Peng Wang Yan Li Yujiao Qu Baowei Wang Jingxin Sun Chunwei Miao Ming Huang He Huang Congxiang Zhang 《International Journal of Food Science & Technology》2022,57(6):3428-3439
The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non-covalent bonds, the diffusion and cross-linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs-MP group than in the CMFs-MP group. The CNFs-MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP. 相似文献
6.
7.
Fan Deng-Ping Huang Ziling Zheng Peng Liu Hong Qin Xuebin Van Gool Luc 《国际自动化与计算杂志》2022,19(4):257-287
Machine Intelligence Research - This paper aims to conduct a comprehensive study on facial-sketch synthesis (FSS). However, due to the high cost of obtaining hand-drawn sketch datasets, there is a... 相似文献
8.
Wireless Networks - In this paper, a grouping-based uplink orthogonal frequency division multiple access (OFDMA) random access method is studied which can improve users’ satisfaction in the... 相似文献
9.
Multimedia Tools and Applications - The study presents a new approach to automate segmentation of clinically significant brain tumor and, to a certain extent, addresses two major issues associated... 相似文献
10.