全文获取类型
收费全文 | 151546篇 |
免费 | 15914篇 |
国内免费 | 9771篇 |
专业分类
电工技术 | 11683篇 |
技术理论 | 9篇 |
综合类 | 14497篇 |
化学工业 | 21774篇 |
金属工艺 | 9647篇 |
机械仪表 | 10263篇 |
建筑科学 | 11511篇 |
矿业工程 | 5027篇 |
能源动力 | 4313篇 |
轻工业 | 15959篇 |
水利工程 | 3696篇 |
石油天然气 | 6951篇 |
武器工业 | 1820篇 |
无线电 | 15925篇 |
一般工业技术 | 14859篇 |
冶金工业 | 5779篇 |
原子能技术 | 1898篇 |
自动化技术 | 21620篇 |
出版年
2024年 | 817篇 |
2023年 | 2560篇 |
2022年 | 5527篇 |
2021年 | 6972篇 |
2020年 | 5275篇 |
2019年 | 3951篇 |
2018年 | 4285篇 |
2017年 | 4978篇 |
2016年 | 4355篇 |
2015年 | 6670篇 |
2014年 | 8434篇 |
2013年 | 9679篇 |
2012年 | 11643篇 |
2011年 | 12576篇 |
2010年 | 11391篇 |
2009年 | 10776篇 |
2008年 | 10872篇 |
2007年 | 10317篇 |
2006年 | 9350篇 |
2005年 | 7533篇 |
2004年 | 5403篇 |
2003年 | 4252篇 |
2002年 | 4192篇 |
2001年 | 3611篇 |
2000年 | 2967篇 |
1999年 | 2171篇 |
1998年 | 1415篇 |
1997年 | 1082篇 |
1996年 | 964篇 |
1995年 | 725篇 |
1994年 | 589篇 |
1993年 | 421篇 |
1992年 | 353篇 |
1991年 | 262篇 |
1990年 | 183篇 |
1989年 | 167篇 |
1988年 | 103篇 |
1987年 | 83篇 |
1986年 | 72篇 |
1985年 | 35篇 |
1984年 | 24篇 |
1983年 | 28篇 |
1982年 | 26篇 |
1981年 | 31篇 |
1980年 | 44篇 |
1979年 | 22篇 |
1978年 | 3篇 |
1965年 | 3篇 |
1959年 | 16篇 |
1951年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Cuiping Yu Shuang Sun Sihui Li Huijia Yan Henan Zou 《International Journal of Food Science & Technology》2022,57(2):1173-1185
In this study, the effect of high-intensity ultrasound (HIUS) (200 and 400 W for 0, 5, 10 and 15 min respectively) on conformational changes, physicochemical, rheological and emulsifying properties of scallop (Patinopecten yessoensis) myofibrillar protein (SMP) was investigated. HIUS-treated SMP had lower α-helix content and higher β-sheet content compared with the native SMP. HIUS treatment induced the unfolding of SMP and increased the surface hydrophobicity. The particle size of SMP decreased and the absolute zeta-potential increased after ultrasonication, which in turn increased the solubility of SMP. The conformational changes and the improvement of physicochemical properties of SMP increased the ability for SMP to lower the interfacial tension at the oil–water interface and increased the percentage of adsorbed protein. As a result, the emulsifying properties, rheological properties of SMP and storage stability of emulsions were also improved. In conclusion, HIUS treatment has future potential for improving the emulsifying properties of SMP. 相似文献
13.
14.
Yan He Kangren Kong Zhengxi Guo Weifeng Fang Zaiqiang Ma Haihua Pan Ruikang Tang Zhaoming Liu 《Advanced functional materials》2021,31(26):2101291
Sensitivity and multi-directional motivation are major two factors for developing optimized humidity-response materials, which are promising for sensing, energy production, etc. Organic functional groups are commonly used as the water sensitive units through hydrogen bond interactions with water molecules in actuators. The multi-coordination ability of inorganic ions implies that the inorganic ionic compounds are potentially superior water sensitive units. However, the particle forms of inorganic ionic compounds produced by classical nucleation limit the number of exposed ions to interact with water. Recent progress on the inorganic ionic oligomers has broken through the limitation of classical nucleation, and realized the molecular-scaled incorporation of inorganic ionic compounds into an organic matrix. Here, the incorporation of hydrophilic calcium carbonate ionic oligomers into hydrophobic poly(vinylidene fluoride) (PVDF) is demonstrated. The ultra-small calcium carbonate oligomers within a PVDF film endow it with an ultra-sensitive, reversible, and bidirectional response. The motivation ability is superior to other bidirectional humidity-actuators at present, which realizes self-motivation on an ice surface, converting the chemical potential energy of the humidity gradient from ice to kinetic energy. 相似文献
15.
一场新型冠状病毒肺炎疫情的爆发给染料行业的发展带来了影响,既有负面消极,也有积极影响。疫情将促进染料行业绿色发展,推动染料行业走向信息化、智能化时代,走向高质量发展,指出只要坚持绿色、创新和智能化,就能战胜疫情,推动中国染料行业稳健发展。 相似文献
16.
17.
董家埝银矿是豫西小秦岭矿集区南成矿带目前发现的唯一大型矿床。为了矿床深部勘查工作的顺利进行,了解有用元素在垂向上的变化规律,选用原生晕地球化学方法,通过典型矿床剖面的原生晕特征研究,实现对深部矿体变化趋势的判断。经计算,确定As、Sb、Ag、Au、Cu、Pb、Zn、Co和Mo等9种元素可作为指示元素,其中As和Sb为前缘晕指示元素,Ag、Au、Cu、Pb和Zn为近矿晕指示元素,Co和Mo为尾晕指示元素。分带指数和浓集指数2种方法计算得出的元素在分带序列上的位置总体趋势一致。用分带指数法确定的主矿体自上而下的原生晕轴向分带序列为Co-Mo-Cu-Au-Sb-Zn-Pb-Ag-As,出现"反分带"现象。结合原生晕地球化学参数变化特征、矿体剥蚀程度研究和理想模型,预测M1-I主矿体向深部仍有较大的延伸。研究成果可以为区域同类型矿化地质体深部的趋势判断和决策提供参考。 相似文献
18.
Yan Jing Zhu Rongying Wu Fan Zhao Ziyin Ye Huan Hou Mengying Liu Yong Yin Lichen 《Nano Research》2020,13(10):2706-2715
Nano Research - Insufficient intratumoral penetration greatly hurdles the anticancer performance of nanomedicine. To realize highly efficient tumor penetration in a precisely and spatiotemporally... 相似文献
19.
针对传统铁矿石磁化焙烧技术与装备存在焙烧产品质量差、产能低、能耗高和环境污染严重等问题,创造性提出了一种“预热-蓄热还原-再氧化”悬浮磁化焙烧新工艺。该工艺具有原料适应性广、焙烧产品质量均匀、回收率高、生产能耗低、无污染等特点,适合处理赤铁矿、褐铁矿、菱铁矿及其混合型难选铁矿石。通过多年的潜心基础研究与技术攻关,形成了非均质矿石颗粒悬浮态流动控制、蓄热式高效低温还原、铁物相精准调控与余热同步回收等一系列关键技术,建成了500kg/h复杂难选铁矿石悬浮磁化焙烧-高效分选半工业试验平台。 相似文献
20.
To improve the convertibility of reconfigurable manufacturing system (RMS), the concept of delayed reconfigurable manufacturing system (D-RMS) was proposed. RMS and D-RMS are both constructed around part family. However, D-RMS may suffer from ultra-long system problem with unacceptable idle machines using generic RMS part families. Besides, considering the complex basic system structure of D-RMS, machine selection of D-RMS should be addressed, including dedicated machine, flexible machine, and reconfigurable machine. Therefore, a system design method for D-RMS based on part family grouping and machine selection is proposed. Firstly, a part family grouping method is proposed for D-RMS that groups the parts with more former common operations into the same part family. The concept of longest relative position common operation subsequence (LPCS) is proposed. The similarity coefficient among the parts is calculated based on LPCS. The reciprocal value of the operation position of LPCS is adopted as the characteristic value. The average linkage clustering (ALC) algorithm is used to cluster the parts. Secondly, a machine selection method is proposed to complete the system design of D-RMS, including machine selection rules and the dividing point decision model. Finally, a case study is given to implement and verify the proposed system design method for D-RMS. The results show that the proposed system design method is effective, which can group parts with more former common operations into the same part family and select appropriate machine types. 相似文献