全文获取类型
收费全文 | 176206篇 |
免费 | 9217篇 |
国内免费 | 4734篇 |
学科分类
工业技术 | 190157篇 |
出版年
2024年 | 157篇 |
2023年 | 1384篇 |
2022年 | 2059篇 |
2021年 | 3492篇 |
2020年 | 2649篇 |
2019年 | 2311篇 |
2018年 | 16564篇 |
2017年 | 15880篇 |
2016年 | 12497篇 |
2015年 | 4331篇 |
2014年 | 4833篇 |
2013年 | 5909篇 |
2012年 | 9019篇 |
2011年 | 15847篇 |
2010年 | 14075篇 |
2009年 | 10906篇 |
2008年 | 12183篇 |
2007年 | 12894篇 |
2006年 | 5379篇 |
2005年 | 5742篇 |
2004年 | 4368篇 |
2003年 | 4169篇 |
2002年 | 3768篇 |
2001年 | 2814篇 |
2000年 | 2521篇 |
1999年 | 2373篇 |
1998年 | 1991篇 |
1997年 | 1695篇 |
1996年 | 1622篇 |
1995年 | 1311篇 |
1994年 | 1127篇 |
1993年 | 818篇 |
1992年 | 664篇 |
1991年 | 527篇 |
1990年 | 379篇 |
1989年 | 310篇 |
1988年 | 266篇 |
1987年 | 177篇 |
1986年 | 129篇 |
1985年 | 96篇 |
1984年 | 85篇 |
1983年 | 39篇 |
1982年 | 57篇 |
1981年 | 43篇 |
1968年 | 45篇 |
1966年 | 44篇 |
1965年 | 46篇 |
1959年 | 39篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
2.
Liu Yang Pengfei Yu Wenyuan Li Fengliang Cao Xin Jin Sheng Xue Xianglong Zhang Tingwei Zhang Mingbo Wu Wenting Wu 《American Institute of Chemical Engineers》2022,68(9):e17760
Hydrogen peroxide (H2O2) has been listed as one of the 100 most important chemicals in the world. However, huge amount of residual H2O2 is hard to timely decomposed into O2 and H2O under acidic condition, easily resulting in explosion hazard. Here, we reported a core–shell structure catalyst, that is graphene with Co N structure encapsulated Co nanoparticles. Co N graphene shell serves as the active site for the H2O2 decomposition, and Co core further enhance this decomposition. Benefiting from it, the H2O2 decomposition were close to 100% after 6 cycles without pH adjustment, which increased 6 orders of magnitude compared with no catalyst. At the same time, the O2 generation reached 99.67% in 2 h with little metal leaching, and ·OH has been greatly inhibited to only 0.08%. This work can cleanly remove H2O2 with little deep oxidation and protect the process of H2O2 utilization to achieve a safer world. 相似文献
3.
建立高效液相色谱法测定化妆品中依克多因的分析方法,采用Agilent Poroshell 120 EC-C18色谱柱(100 mm×3.0 mm,2.7μm)分离,以甲醇和p H为3.0的40 mmol/L磷酸二氢钠-10 mmol/L 1-庚烷磺酸钠缓冲溶液梯度洗脱,流速0.8 m L/min,柱温30℃,检测波长210 nm。采用外标法定量测定化妆品中的依克多因含量。结果表明,依克多因在5~800 mg/L的质量浓度范围内呈现良好线性关系,相关系数为0.999 8,方法的检出限和定量限分别为0.3和1.0 mg/L。该方法具有分离效率高、分析时间短、节省溶剂等优点,解决了依克多因在C18色谱柱上保留弱的问题。 相似文献
4.
5.
6.
Journal of Materials Science - Silicon is getting much attention as the promising next-generation negative electrode materials for lithium-ion batteries with the advantages of abundance, high... 相似文献
7.
8.
9.
10.
Mengwei Liu Jin Zhao Shunzo Shimai Dan Han Jian Zhang Shiwei Wang 《Journal of the American Ceramic Society》2022,105(7):4632-4638
MgAl2O4 transparent ceramics were shaped by a commonly used polyacrylic acid (PAA), which acted as both dispersant and gelling agent. The spinel slurries were prepared by ball-milling MgAl2O4 powder, PAA, and water in an attrition mill. The gelling of slurries happened at room temperature in air atmosphere without any other organic additive. The gelling mechanism was the formation of chelates between Mg2+ and carboxyl groups (-COO−) of PAA. The frequency-based testing method was applied to investigate the gelling process of the as-prepared slurry. In addition, a novel in situ characterization method based on a modified indentation testing was invented to better understand the strengthening of the wet green body with time and to guide when demolding could be carried out. After sintering, transparent MgAl2O4 ceramics with high in-line transmittance were resulted. 相似文献