全文获取类型
收费全文 | 6616篇 |
免费 | 600篇 |
国内免费 | 403篇 |
专业分类
电工技术 | 615篇 |
综合类 | 764篇 |
化学工业 | 187篇 |
金属工艺 | 437篇 |
机械仪表 | 742篇 |
建筑科学 | 1031篇 |
矿业工程 | 181篇 |
能源动力 | 129篇 |
轻工业 | 100篇 |
水利工程 | 108篇 |
石油天然气 | 137篇 |
武器工业 | 57篇 |
无线电 | 1050篇 |
一般工业技术 | 380篇 |
冶金工业 | 236篇 |
原子能技术 | 43篇 |
自动化技术 | 1422篇 |
出版年
2024年 | 24篇 |
2023年 | 75篇 |
2022年 | 164篇 |
2021年 | 207篇 |
2020年 | 218篇 |
2019年 | 142篇 |
2018年 | 154篇 |
2017年 | 195篇 |
2016年 | 214篇 |
2015年 | 305篇 |
2014年 | 585篇 |
2013年 | 411篇 |
2012年 | 560篇 |
2011年 | 583篇 |
2010年 | 351篇 |
2009年 | 392篇 |
2008年 | 315篇 |
2007年 | 463篇 |
2006年 | 415篇 |
2005年 | 358篇 |
2004年 | 271篇 |
2003年 | 259篇 |
2002年 | 197篇 |
2001年 | 202篇 |
2000年 | 114篇 |
1999年 | 99篇 |
1998年 | 65篇 |
1997年 | 50篇 |
1996年 | 45篇 |
1995年 | 32篇 |
1994年 | 42篇 |
1993年 | 27篇 |
1992年 | 23篇 |
1991年 | 12篇 |
1990年 | 15篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有7619条查询结果,搜索用时 15 毫秒
1.
2.
加快塑料技术中心建设提高新产品开发水平 总被引:2,自引:2,他引:0
对中国石油化工集团公司(简称中国石化)合成树脂生产及加工应用技术的现状进行了分析,指出中国石化应加快建设塑料加工应用技术中心,为塑料产品的加工用户提供高技术水平和快捷周到的技术服务,在合成树脂新产品开发和产品结构调整中发挥积极作用,以提高合成树脂产品的市场竞争力。 相似文献
3.
A problem of deformation of a curved shell loaded by internal pressure, axial force, and temperature difference is discussed. Physical equations are derived whereby the displacements and angles of rotation of the line of centers of mass of cross sections of a shell are related to loading parameters. A general constitutive set of equations for a curved element during its deformation is given. Using a method of initial parameters, an analytical solution is obtained for the differential equations for displacements and angles of rotation of the center line allowing for the action of distributed forces and moments. 相似文献
4.
会计集中核算制度是财政体制改革的一项重要举措,它对改变现行财政资金分散收付方式发挥了很大的作用.应在会计集中核算的基础上建立行业财务管理中心,并作为会计集中核算改革的进一步深入和补充.探讨了建立行业财务管理中心的重要性和必要性以及行业财务管理中心的模式,并在行业财务管理中心引入融资理念. 相似文献
5.
Karen S. Servilla Antonios H. Tzamaloukas Charles Carter Glen H. Murata 《Hemodialysis international. International Symposium on Home Hemodialysis》2002,6(1):35-39
We developed a composite compliance index as the sum of the compliance scores for interdialytic weight gain (IDWG), pre‐dialysis serum potassium and phosphorus concentrations (each scored from zero to 3, with 3 indicating the poorest compliance), and skipping hemodialysis sessions (scored from zero to 9, with 9 indicating the poorest compliance). We used this composite score to prospectively evaluate compliance in 25 prevalent hemodialysis patients over a period of 1 year. We then followed these patients for another 3.5 years. The patients studied were divided into two groups: group A (poor compliance) consisted of 9 subjects with composite score ≥ 9 (13.2 ± 3.2); group B (better compliance) consisted of 16 subjects with composite score < 9 (4.7 ± 1.8). Age, duration of hemodialysis, and frequency of diabetes mellitus did not differ between the groups. Group A contained higher fractions of subjects with history of alcoholism (66.7% vs 12.5%, p = 0.010), other substance addiction (44.4% vs 0%, p = 0.010), and severe psychosocial problems (88.9% vs 18.8%, p = 0.002). Mean survival from the beginning of observation, estimated by actuarial life‐table survival analysis, was 1.19 years in group A and 2.60 years in group B (p = 0.0265). A composite compliance index incorporating domains indicating adherence to diet, medications, and dialysis schedule identified other behavioral problems in poorly compliant patients. Hemodialysis patients characterized by this composite index as poorly compliant had shortened survival. 相似文献
6.
Ricardo Lima Author Vitae Author Vitae Claudio Reineri Author Vitae Author Vitae 《Computers & Electrical Engineering》2008,34(6):520-530
This paper presents a novel concept for power quality hardware and software architecture. Software tools related to detection, classification and characterization of power quality events can be integrated into a Distribution Control Center in which the interconnection between different subsystems is being carried out through the Internet allowing flexibility to the system. This system is implemented using wavelet analysis applied in all proposed algorithms. Different power quality events are taken as examples to illustrate the capabilities of the proposed method. The obtained results reveal that the proposed architecture is feasible to be implemented as an integral part of a control center system.The proposed system has the property of fast and accurate detection and classification of any power quality disturbance event and introduces a new PQ index determination that allows characterizing any type of disturbance including the non-periodic signals. 相似文献
7.
Yuan-Hui Yu 《中国电子科技》2007,5(3):215-217
The technical characters of mobile agent (MA) originated in the distributional artificial intelligence domain is introduced. A network management construction based on agent (NMCA) is then proposed. The NMCA structure features are elaborated in detail. A prototype design of NMCA is given by using the jKQML programming. The establishment of NMCA platform will be helpful to reduce the correspondence load of network management and improves the efficiency and the expansion ability of network management systems. 相似文献
8.
9.
首先以 HERMLE C1200 U 为例分析了五轴铣削加工中心的基本结构,然后据此给出了涉及多轴铣削加工中心后置处理角度分配和坐标变换的数学模型,最后介绍了以此数学模型为核心,为UG 软件开发的后置处理软件 UG-HERP1.0的解决方案。 相似文献
10.
本文报道了CaAs∶Er、InP∶Yb发光样品的二次离子质谱、X-射线双晶衍射测量结果及其与Er离子的表面成份的关系.分析讨论了退火损伤对GaAs∶Er和InP∶Yb发光的影响以及Er~(3+)复合体发光中心模型. 相似文献