全文获取类型
收费全文 | 16151篇 |
免费 | 1335篇 |
国内免费 | 1238篇 |
学科分类
工业技术 | 18724篇 |
出版年
2024年 | 25篇 |
2023年 | 101篇 |
2022年 | 216篇 |
2021年 | 276篇 |
2020年 | 271篇 |
2019年 | 263篇 |
2018年 | 276篇 |
2017年 | 414篇 |
2016年 | 452篇 |
2015年 | 576篇 |
2014年 | 976篇 |
2013年 | 1051篇 |
2012年 | 1078篇 |
2011年 | 1293篇 |
2010年 | 969篇 |
2009年 | 1112篇 |
2008年 | 1050篇 |
2007年 | 1232篇 |
2006年 | 1110篇 |
2005年 | 921篇 |
2004年 | 804篇 |
2003年 | 772篇 |
2002年 | 590篇 |
2001年 | 414篇 |
2000年 | 388篇 |
1999年 | 326篇 |
1998年 | 306篇 |
1997年 | 217篇 |
1996年 | 196篇 |
1995年 | 176篇 |
1994年 | 150篇 |
1993年 | 114篇 |
1992年 | 86篇 |
1991年 | 84篇 |
1990年 | 58篇 |
1989年 | 61篇 |
1988年 | 45篇 |
1987年 | 30篇 |
1986年 | 43篇 |
1985年 | 38篇 |
1984年 | 37篇 |
1983年 | 23篇 |
1982年 | 26篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1973年 | 3篇 |
1959年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Code comments convey information about the programmers' intention in a more explicit but less rigorous manner than source code. This information can assist programmers in various tasks, such as code comprehension, reuse, and maintenance. To better understand the properties of the comments existing in the source code, we analyzed more than 450 000 comments across 136 popular open-source software systems coming different domains. We found that the methods involving header comments and internal comments were shown low percentages in software systems, ie, 4.4% and 10.27%, respectively. As an application of our findings, we propose an automatic approach to determine whether a method needs a header comment, known as commenting necessity identification. Specifically, we identify the important factors for determining the commenting necessity of a method and extract them as structural features, syntactic features, and textual features. Then, by applying machine learning techniques and noise-handling techniques, we achieve a precision of 88.5% on eight open-source software from GitHub. The encouraging experimental results demonstrate the feasibility and effectiveness of our approach. 相似文献
42.
43.
随着宽带的不断增长,用户对运营商的快速支撑能力提出了更高的要求。文章探讨了通过"一户一码"系统建设,将用户宽带和IPTV业务二维码化,通过二维码与固网业务进行绑定,用户业务出现故障需要与装维人员联系咨询的时候,可使用微信等第三方扫码工具扫描家中的业务二维码,进行电话联系咨询、业务查询、故障诊断、一键报障,最终使得用户响应速度和服务效率得到很大提高,取得了非常显著的效果。 相似文献
44.
Syed Altan Haider Muhammad Sajid Saeed Iqbal 《International Journal of Hydrogen Energy》2021,46(2):1671-1681
The focus of this study is the use of Machine Learning methods to forecast Solar Hydrogen production potential for the Islamabad region of Pakistan. For this purpose, we chose a Photovoltaic-Electrolytic (PV-E) system to forecast electricity and, hence, hydrogen production. The weather data used for forecasting and simulation were recorded with precise meteorological instruments stationed in Islamabad, over the course of 13 and a half months. Out of the three tested algorithms, Prophet performs the best with Mean Absolute Percentage Error of 3.7%, forecasting a daily average Hydrogen production of 93.3 × 103 kg/Km2. Although, the forecast in this study is made for the month of August and September, during which the local season moves towards winter, this study demonstrates solar hydrogen production, as a green energy source, has a tremendous potential in this region. 相似文献
45.
This paper focuses on exploring conflict-free routes for automated guided vehicles (AGVs) based on quick response (QR) code technology. Intelligent warehousing has become an industrial development trend, with an increasing number of enterprises deploying AGVs based on QR code technology for transportation tasks, especially in large warehouses. Unlike the early single lane path following navigation systems, AGVs using QR code technology can freely switch tracks at any position. And two AGVs can be accommodated side by side. The conditions of conflict-free routes are analyzed firstly when AGVs use QR code navigation system. After that, a route and speed optimization model (RSOM) that aims at minimizing energy consumption and taking conflict-free routes with time windows as the constraint condition is established. Then a branch-and-bound (B&B) algorithm scheme is proposed by altering AGV routes or speed to arrive at schemes with conflict-free routes to complete transportation tasks. Lastly, the effectiveness and validity of our proposed model and algorithm are verified by numerical examples and a case study. The results show that resolving conflicts during route planning for AGVs guided through QR code have advantages over avoiding collision in the running phase by technology and path following techniques in both aspects of solution time and energy. In addition, the established B&B algorithm has better performance than the rapid-exploring random tree (RRT) algorithm in numerical examples. The gaps between them widen as the size of AGVs increases. The research work has potential for application to meet the requirements of AGV development. 相似文献
46.
47.
48.
本文根据信息生态系统理论,首次对资本市场矿产资源信息生态系统内涵,以及矿产资源信息、信息人、信息环境等构成要素进行了定义,分析了资本市场矿产资源信息生态系统特点,并对主要影响因素进行分析;然后以澳大利亚资本市场矿产资源信息生态系统应用为研究对象,剖析其系统构成、系统运行特点及优缺点,并以此重新审视我国矿产资源信息生态系统构成要素和运行特点,认为我国资本市场矿产资源信息发布要求不统一、信息人责任不明确、矿产资源信息环境不健全是目前阻碍矿业资本市场发展的主要问题。通过研究,本文提出应以矿产资源信息系统“三要素”为基础,制定我国资本市场矿产资源信息公开报告规则,建立权责清晰明确的胜任人制度,进一步促进我国资本市场矿产资源信息生态系统发展。 相似文献
49.
50.
矿产资源作为矿业公司持有使用权的核心资产,由于境内外矿业资本市场要求不同,因此境内外发布的矿产资源信息存在较大差异。洛阳钼业是香港交易所和上海证券交所双重上市的矿业公司,根据香港交易所要求,由胜任人按照JORC规则发布独立技术审查报告;根据上海证券交易所等要求,按照我国标准编制核实报告并通过评审备案后,将其作为A股招股说明书的所载内容公开发布。本文以洛阳钼业所属上市资产三道庄钼矿为例,以公开的矿产资源信息为切入点,对境内外首发上市的矿产资源信息发布路径、发布内容以及矿产资源储量对比分析,认为境内外证券交易所矿产资源信息发布要求、采纳的矿产资源储量分类标准和矿产资源储量估算认定体系等要素是导致信息发布存在差异的主要原因,总结了矿业资本市场信息发布差异带来的三点启示,为完善我国矿业资本市场发展,促进矿业行业国际互联互通提供实证。 相似文献