全文获取类型
收费全文 | 181463篇 |
免费 | 27173篇 |
国内免费 | 8046篇 |
专业分类
电工技术 | 11080篇 |
技术理论 | 7篇 |
综合类 | 10889篇 |
化学工业 | 38420篇 |
金属工艺 | 8489篇 |
机械仪表 | 10622篇 |
建筑科学 | 13092篇 |
矿业工程 | 4573篇 |
能源动力 | 5258篇 |
轻工业 | 16459篇 |
水利工程 | 3018篇 |
石油天然气 | 8643篇 |
武器工业 | 1553篇 |
无线电 | 23293篇 |
一般工业技术 | 27480篇 |
冶金工业 | 7307篇 |
原子能技术 | 1824篇 |
自动化技术 | 24675篇 |
出版年
2024年 | 688篇 |
2023年 | 2411篇 |
2022年 | 4345篇 |
2021年 | 6361篇 |
2020年 | 5966篇 |
2019年 | 6773篇 |
2018年 | 7197篇 |
2017年 | 7974篇 |
2016年 | 7754篇 |
2015年 | 9544篇 |
2014年 | 11055篇 |
2013年 | 13506篇 |
2012年 | 12166篇 |
2011年 | 12739篇 |
2010年 | 12130篇 |
2009年 | 11465篇 |
2008年 | 10792篇 |
2007年 | 10294篇 |
2006年 | 9773篇 |
2005年 | 8373篇 |
2004年 | 6305篇 |
2003年 | 5937篇 |
2002年 | 5872篇 |
2001年 | 5176篇 |
2000年 | 4557篇 |
1999年 | 3692篇 |
1998年 | 2576篇 |
1997年 | 2067篇 |
1996年 | 1941篇 |
1995年 | 1619篇 |
1994年 | 1284篇 |
1993年 | 1024篇 |
1992年 | 781篇 |
1991年 | 563篇 |
1990年 | 457篇 |
1989年 | 345篇 |
1988年 | 304篇 |
1987年 | 187篇 |
1986年 | 165篇 |
1985年 | 127篇 |
1984年 | 81篇 |
1983年 | 59篇 |
1982年 | 61篇 |
1981年 | 48篇 |
1980年 | 38篇 |
1979年 | 21篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1959年 | 11篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Science China Technological Sciences - Accurate modelling of lithium ion batteries is crucial for battery management in electric vehicles. Recent studies have revealed the fractional order nature... 相似文献
43.
Guoxiang
Zhang Junyu Xiang 《International journal for numerical methods in engineering》2020,121(15):3339-3361
A new eight-node conforming quadrilateral element with high-order completeness, denoted as QH8-C1, is proposed in this article. First, expressions for the interpolation displacement function satisfying the requirements for high-order completeness in the global coordinate system are constructed. Second, the displacement function expression in global coordinates is transformed into isoparametric coordinates, and the relationships between the two series of coefficients for the two kinds of displacement function expressions are found. Third, the displacement function expression is modified to satisfy the requirements of nodal freedom and interelement boundary continuity. The key to the new element construction is the derivation of the linear relationship expressions among 12 coefficients of element displacement interpolation polynomials in the global and isoparametric coordinate systems. As a result, the relationship between quadratic completeness and interelement continuity is explicitly given, and a proof of the completeness and the continuity was conducted to theoretically guarantee the validity of the derivation results. Furthermore, in order to verify the correctness of the theoretical work, nine numerical examples were performed. The computation results from these examples demonstrate that QH8-C1 exhibited excellent performance, including high simulation accuracy, fast convergence, insensitivity to mesh distortion, and monotonic convergence. 相似文献
44.
45.
46.
根据柴油机机体裂纹产生的原因,对机体裂纹缺陷进行分析,找到了机体裂纹产生的主要原因。其主要原因可概括为铸件结构、化学成分、铸件补缩条件及开箱温度等,针对裂纹的主要原因采取相应的措施后,裂纹缺陷得到了根本的控制。 相似文献
47.
SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
48.
Efficacy of Crude and Purified Chitinases (SsChi50) Extracted from Offal Red Scorpion Fish in Biological Control of Chickpea Weevil (Callosobruchus maculatus L.)
下载免费PDF全文
![点击此处可从《Journal of Food Processing and Preservation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
49.
Quality enhancement of the abundant under‐valued crustacean,lobster krill (Munida spp.), during its chilled storage
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Bibiana García‐Soto José M. Miranda Jorge Barros‐Velázquez Santiago P. Aubourg 《International Journal of Food Science & Technology》2015,50(3):708-716
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product. 相似文献
50.