全文获取类型
收费全文 | 18382篇 |
免费 | 1173篇 |
国内免费 | 705篇 |
专业分类
电工技术 | 602篇 |
综合类 | 1236篇 |
化学工业 | 2519篇 |
金属工艺 | 1724篇 |
机械仪表 | 2738篇 |
建筑科学 | 832篇 |
矿业工程 | 811篇 |
能源动力 | 418篇 |
轻工业 | 706篇 |
水利工程 | 213篇 |
石油天然气 | 438篇 |
武器工业 | 289篇 |
无线电 | 1607篇 |
一般工业技术 | 1478篇 |
冶金工业 | 867篇 |
原子能技术 | 69篇 |
自动化技术 | 3713篇 |
出版年
2024年 | 51篇 |
2023年 | 164篇 |
2022年 | 281篇 |
2021年 | 395篇 |
2020年 | 407篇 |
2019年 | 361篇 |
2018年 | 313篇 |
2017年 | 454篇 |
2016年 | 586篇 |
2015年 | 610篇 |
2014年 | 1065篇 |
2013年 | 1044篇 |
2012年 | 1127篇 |
2011年 | 1404篇 |
2010年 | 981篇 |
2009年 | 976篇 |
2008年 | 941篇 |
2007年 | 1256篇 |
2006年 | 1139篇 |
2005年 | 1059篇 |
2004年 | 894篇 |
2003年 | 812篇 |
2002年 | 699篇 |
2001年 | 563篇 |
2000年 | 552篇 |
1999年 | 416篇 |
1998年 | 349篇 |
1997年 | 276篇 |
1996年 | 225篇 |
1995年 | 180篇 |
1994年 | 189篇 |
1993年 | 112篇 |
1992年 | 80篇 |
1991年 | 70篇 |
1990年 | 49篇 |
1989年 | 42篇 |
1988年 | 32篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 11篇 |
1984年 | 19篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1974年 | 2篇 |
1959年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
1.
An Intermediate Bulk Container (IBC) was punctured during its handling, releasing oil onto soil at an environmentally-sensitive region of Australia. The telehandler did not pierce the plastic of the IBC directly (as was expected) but rather one of the tynes had caught on the underside of the metal base plate, despite numerous controls being in place at time of spill, revealing a previously unreported mechanism for a fluid spill from handling of petroleum hydrocarbons. The diverse investigation team used a root cause analysis (RCA) technique to identify the underlying cause: the inspection process was inadequate with contributing factors of not using a spotter and design of IBC did not anticipate conditions. Engineering controls were put in place as part of the change management process to help prevent spills from occurring from piercing from telehandler tynes on the current project site. 相似文献
2.
Communication between organizations is formalized as process choreographies in daily business. While the correct ordering of exchanged messages can be modeled and enacted with current choreography techniques, no approach exists to describe and automate the exchange of data between processes in a choreography using messages. This paper describes an entirely model-driven approach for BPMN introducing a few concepts that suffice to model data retrieval, data transformation, message exchange, and correlation – four aspects of data exchange. For automation, this work utilizes a recent concept to enact data dependencies in internal processes. We present a modeling guideline to derive local process models from a given choreography; their operational semantics allows to correctly enact the entire choreography from the derived models only including the exchange of data. Targeting on successful interactions, we discuss means to ensure correct process choreography modeling. Finally, we implemented our approach by extending the camunda BPM platform with our approach and show its feasibility by realizing all service interaction patterns using only model-based concepts. 相似文献
3.
Process mining techniques relate observed behavior (i.e., event logs) to modeled behavior (e.g., a BPMN model or a Petri net). Process models can be discovered from event logs and conformance checking techniques can be used to detect and diagnose differences between observed and modeled behavior. Existing process mining techniques can only uncover these differences, but the actual repair of the model is left to the user and is not supported. In this paper we investigate the problem of repairing a process model w.r.t. a log such that the resulting model can replay the log (i.e., conforms to it) and is as similar as possible to the original model. To solve the problem, we use an existing conformance checker that aligns the runs of the given process model to the traces in the log. Based on this information, we decompose the log into several sublogs of non-fitting subtraces. For each sublog, either a loop is discovered that can replay the sublog or a subprocess is derived that is then added to the original model at the appropriate location. The approach is implemented in the process mining toolkit ProM and has been validated on logs and models from several Dutch municipalities. 相似文献
4.
Process object is the instance of process. Vertexes and edges are in the graph of process object. There are different types of the object itself and the associations between object. For the large-scale data, there are many changes reflected. Recently, how to find appropriate real-time data for process object becomes a hot research topic. Data sampling is a kind of finding c hanges o f p rocess o bjects. There i s r equirements f or s ampling to be adaptive to underlying distribution of data stream. In this paper, we have proposed a adaptive data sampling mechanism to find a ppropriate d ata t o m odeling. F irst o f all, we use concept drift to make the partition of the life cycle of process object. Then, entity community detection is proposed to find changes. Finally, we propose stream-based real-time optimization of data sampling. Contributions of this paper are concept drift, community detection, and stream-based real-time computing. Experiments show the effectiveness and feasibility of our proposed adaptive data sampling mechanism for process object. 相似文献
5.
6.
卤水井测试的最大技术难题是井筒结晶堵塞问题。为解决这个问题,以四川邛崃平落坝构造高浓度卤水井测试为例,从卤水组分、温度、流速及管材等方面,分析卤水井开采测试中结晶产生的影响因素;从卤水的化学性质出发,探讨工具防腐技术;结合现场应用效果,进一步优化管柱结构。 相似文献
7.
为了实现对微小环片零件的自动化装配,搭建了自动装配系统.通过4根直线导向轴与4个直线轴承来提高系统的导向精度和刚度.采用直线导轨进行各装配作业模块之间的切换,保证了微小环片零件的自动装配与取出.在环片的装配方向上,螺旋升降机和光栅尺实现环片的位置精度控制.在Lab VIEW编程环境中,采用分层软件架构和模块化控制思想,避免了不必要的数据循环检测与丢失,能够达到环片组件的装配精度要求.控制系统分为系统初始化模块、参数设置模块、装配模块和取出模块,自动装配系统通过各个模块间的相互交流配合完成装配任务.采用本文中自动装配系统装配环片的实验结果表明,环片零件装配的最大位置误差为26μm,垂直度误差为17μm,平均装配时间为75 s/片,可满足环片组件所需的精度要求. 相似文献
8.
文章中主要采用有机溶剂萃取法(OSE)对高浓度石油污染土壤进行修复,经过精馏操作,有效回收原油,建立脱附等温曲线,研究了石油污染物在土壤-有机溶剂两相间的迁移规律。 相似文献
9.
沙漠地区高精度地震资料处理技术 总被引:1,自引:1,他引:0
受静校正及各种类型干扰的影响,西部沙漠地区地震资料的高精度处理较东部地区有更大的难度。对准噶尔盆地中部Ⅱ区、Ⅲ区、Ⅳ区、顺托果勒等区块地震资料在振幅恢复、静校正、去除各类噪音、高精度速度分析及叠前、叠后子波处理等方面进行了大量的试验与研究,形成了较为系统的高精度地震资料处理技术,在西部不同区块地震资料处理中取得了较好的应用效果。 相似文献
10.