全文获取类型
收费全文 | 49657篇 |
免费 | 5462篇 |
国内免费 | 3348篇 |
专业分类
电工技术 | 3889篇 |
综合类 | 4817篇 |
化学工业 | 6422篇 |
金属工艺 | 3655篇 |
机械仪表 | 3157篇 |
建筑科学 | 3691篇 |
矿业工程 | 1782篇 |
能源动力 | 1556篇 |
轻工业 | 5330篇 |
水利工程 | 1484篇 |
石油天然气 | 1299篇 |
武器工业 | 704篇 |
无线电 | 5851篇 |
一般工业技术 | 5018篇 |
冶金工业 | 2865篇 |
原子能技术 | 623篇 |
自动化技术 | 6324篇 |
出版年
2024年 | 255篇 |
2023年 | 802篇 |
2022年 | 1818篇 |
2021年 | 2318篇 |
2020年 | 1607篇 |
2019年 | 1174篇 |
2018年 | 1329篇 |
2017年 | 1402篇 |
2016年 | 1319篇 |
2015年 | 2126篇 |
2014年 | 2530篇 |
2013年 | 3288篇 |
2012年 | 3944篇 |
2011年 | 4041篇 |
2010年 | 3735篇 |
2009年 | 3710篇 |
2008年 | 3809篇 |
2007年 | 3709篇 |
2006年 | 3153篇 |
2005年 | 2535篇 |
2004年 | 1989篇 |
2003年 | 1420篇 |
2002年 | 1262篇 |
2001年 | 1203篇 |
2000年 | 919篇 |
1999年 | 453篇 |
1998年 | 533篇 |
1997年 | 376篇 |
1996年 | 247篇 |
1995年 | 173篇 |
1994年 | 145篇 |
1993年 | 176篇 |
1992年 | 103篇 |
1991年 | 92篇 |
1990年 | 90篇 |
1989年 | 70篇 |
1988年 | 59篇 |
1987年 | 65篇 |
1986年 | 67篇 |
1985年 | 37篇 |
1984年 | 37篇 |
1983年 | 22篇 |
1981年 | 49篇 |
1980年 | 37篇 |
1979年 | 29篇 |
1978年 | 26篇 |
1977年 | 40篇 |
1976年 | 43篇 |
1971年 | 12篇 |
1951年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
恶意代码数量已经呈现爆炸式增长,对于恶意代码的检测防护显得尤为重要.近几年,基于深度学习的恶意代码检测方法开始出现,基于此,提出一种新的检测方法,将恶意代码二进制文件转化为十进制数组,并利用一维卷积神经网络(1 Dimention Convolutional Neural Networks,1D CNN)对数组进行分类和识别.针对代码家族之间数量不平衡的现象,该算法选择在分类预测上表现良好的XGBoost,并对Vision Research Lab中的25个不同恶意软件家族的9458个恶意软件样本进行了实验.实验结果表明,所提的方法分类预测精度达到了97%. 相似文献
2.
Zhen Hong Mingshan Xue Yidan Luo Zuozhu Yin Chan Xie Junfei Ou Fajun Wang 《应用聚合物科学杂志》2021,138(2):49657
With the continuous development of bionics, such as, geckos and virginia creeper with both superhydrophobic and super-adhesive, the surface wetting and super-adhesive properties of various porous materials have attracted extensive attention of the scientific and medical communities. Here, the honeycomb polyurethane (PU) porous films with strong adhesion were successfully prepared by microphase separation method and the effects of growth parameters on their microstructure and adhesive strength to ice were investigated. It was found that a high relative humidity (e.g., 100%) and a low solution concentration (e.g., 2%) facilitated the formation of ordered honeycomb PU porous films, and as-prepared PU pores with average pore diameter as small as 5 μm are better ordered and more uniform than these in related documents. Although the contact angle of water droplets on the surface of PU porous films increased from the premodification value of 85–130° to more than 160° after surface modification with polydopamine (PDA), the corresponding rolling angle remained approximately constant (180°), indicating that the surface of PU porous films has strong adhesion similar to geckos and virginia creeper. Furthermore, at lower temperature, the PU porous films exhibited the high adhesive strength of 142.13 kPa on ice, which was strongly dependent on the porous microstructures and surface compositions. The improved adhesive behavior to ice of honeycomb PU porous films modified with PDA provides new strategies for surface modification of materials and potential applications in medical domain. 相似文献
3.
目的 针对面向老龄化社会的产品及产品服务系统设计,将赋能的设计理念和价值引入其中,探索设计结果提升老年人能动性和参与性的赋能品质,为设计师开展设计赋能实践提供参考.方法 以设计教学中的学生设计方案作为研究材料,邀请设计研究者参与工作坊,对设计结果的赋能属性进行分析,并通过聚类获得类别化的设计属性,产生了能描述赋能品质的属性词汇表.结果 总结了包含5组形容词组的设计赋能品质集,这一集合包含"顺应性"和"激励性"两个面向.结论 研究结果为设计师进行老龄化设计提供了知识参考,有助于提升设计师的赋能意识.揭示了设计赋能充满矛盾性的品质,提出面向老龄化的设计赋能需要在"顺应"和"激励"之间找到平衡. 相似文献
5.
材料化学专业英语是材料化学专业最重要的专业课程之一,专业英语的学习可为学生的专业论文写作和国际交流奠定坚实的基础。该研究对当前材料化学专业英语教学中存在的一些问题进行了分析,并从教学内容、教学方法、教师素质等方面就如何提高材料化学专业英语的教学效果进行了探讨,以期对改善教学质量和提高学生学习兴趣等方面有所促进。 相似文献
6.
Ava Kwong Cecilia Y. S. Ho Vivian Y. Shin Chun Hang Au Tsun Leung Chan Edmond S. K. Ma 《International journal of molecular sciences》2021,22(2)
The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers. 相似文献
7.
Wesley P. Chan Hiroto Mizohana Xiangyu Chen Yasuto Shiigi Yoshiyuki Yamanoue Masaki Nagatsuka Masayuki Inaba 《野外机器人技术杂志》2019,36(1):17-33
The use of field robots can greatly decrease the amount of time, effort, and associated risk compared to if human workers were to carryout certain tasks such as disaster response. However, transportability and reliability remain two main issues for most current robot systems. To address the issue of transportability, we have developed a lightweight modularizable platform named AeroArm. To address the issue of reliability, we utilize a multimodal sensing approach, combining the use of multiple sensors and sensor types, and the use of different detection algorithms, as well as active continuous closed‐loop feedback to accurately estimate the state of the robot with respect to the environment. We used Challenge 2 of the 2017 Mohammed Bin Zayed International Robotics Competition as an example outdoor manipulation task, demonstrating the capabilities of our robot system and approach in achieving reliable performance in the fields, and ranked fifth place internationally in the competition. 相似文献
8.
9.
Sustainable and efficient food supply chain has become an essential component of one’s life. The model proposed in this paper is deeply linked to people's quality of life as a result of which there is a large incentive to fulfil customer demands through it. This proposed model can enhance food quality by making the best possible food quality accessible to customers, construct a sustainable logistics system considering its environmental impact and ensure the customer demand to be fulfilled as fast as possible. In this paper, an extended model is examined that builds a unified planning problem for efficient food logistics operations where four important objectives are viewed: minimising the total expense of the system, maximising the average food quality along with the minimisation of the amount of CO2 emissions in transportation along with production and total weighted delivery lead time minimisation. A four objective mixed integer linear programming model for intelligent food logistics system is developed in the paper. The optimisation of the formulated mathematical model is proposed using a modified multi-objective particle swarm optimisation algorithm with multiple social structures: MO-GLNPSO (Multi-Objective Global Local Near-Neighbour Particle Swarm Optimisation). Computational results of a case study on a given dataset as well as on multiple small, medium and large-scale datasets followed by sensitivity analysis show the potency and effectiveness of the introduced method. Lastly, there has been a scope for future study displayed which would lead to the further progress of these types of models. 相似文献
10.