全文获取类型
收费全文 | 6904篇 |
免费 | 1040篇 |
国内免费 | 671篇 |
专业分类
电工技术 | 483篇 |
综合类 | 494篇 |
化学工业 | 1274篇 |
金属工艺 | 140篇 |
机械仪表 | 466篇 |
建筑科学 | 355篇 |
矿业工程 | 90篇 |
能源动力 | 146篇 |
轻工业 | 280篇 |
水利工程 | 133篇 |
石油天然气 | 176篇 |
武器工业 | 62篇 |
无线电 | 647篇 |
一般工业技术 | 571篇 |
冶金工业 | 160篇 |
原子能技术 | 116篇 |
自动化技术 | 3022篇 |
出版年
2024年 | 31篇 |
2023年 | 117篇 |
2022年 | 220篇 |
2021年 | 232篇 |
2020年 | 271篇 |
2019年 | 212篇 |
2018年 | 198篇 |
2017年 | 241篇 |
2016年 | 294篇 |
2015年 | 298篇 |
2014年 | 467篇 |
2013年 | 499篇 |
2012年 | 552篇 |
2011年 | 534篇 |
2010年 | 431篇 |
2009年 | 427篇 |
2008年 | 429篇 |
2007年 | 493篇 |
2006年 | 424篇 |
2005年 | 409篇 |
2004年 | 302篇 |
2003年 | 271篇 |
2002年 | 233篇 |
2001年 | 157篇 |
2000年 | 166篇 |
1999年 | 130篇 |
1998年 | 96篇 |
1997年 | 76篇 |
1996年 | 63篇 |
1995年 | 55篇 |
1994年 | 61篇 |
1993年 | 44篇 |
1992年 | 37篇 |
1991年 | 27篇 |
1990年 | 26篇 |
1989年 | 23篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1963年 | 1篇 |
1961年 | 1篇 |
1951年 | 2篇 |
排序方式: 共有8615条查询结果,搜索用时 468 毫秒
41.
42.
43.
Luciana Juncioni de Arauz Angela Faustino Jozala Gabriel Soares Pinheiro Priscila Gava Mazzola Adalberto Pessoa Júnior Thereza Christina Vessoni Penna 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(3):325-328
BACKGROUND: Nisin is a commercially available bacteriocin produced by Lactococcus lactis ATCC 11454 and used as a natural agent in the biopreservation of food. In the current investigation, milk whey, a byproduct from dairy industries was used as a fermentation substrate for the production of nisin. Lactococcus lactis ATCC 11454 was developed in a rotary shaker (30 °C/36 h/100 rpm) using two different media with milk whey (i) without filtration, pH 6.8, adjusted with NaOH 2 mol L?1 and without pH adjustment, both autoclaved at 121 °C for 30 min, and (ii) filtrated (1.20 µm and 0.22 µm membrane filter). These cultures were transferred five times using 5 mL aliquots of broth culture for every new volume of the respective media. RESULTS: The results showed that culture media composed of milk whey without filtration supplied L. lactis its adaptation needs better than filtrated milk whey. Nisin titers, in milk whey without filtration (pH adjusted), was 11120.13 mg L?1 in the second transfer, and up to 1628‐fold higher than the filtrated milk whey, 6.83 mg.L?1 obtained in the firstt transfer. CONCLUSIONS: Biological processing of milk byproducts (milk whey) can be considered a profitable alternative, generating high‐value bioproducts and contributing to decreasing river disposals by dairy industries. Copyright © 2008 Society of Chemical Industry 相似文献
44.
We describe how the tree identification phase of the IEEE 1394 high-performance serial bus (FireWire) protocol is modelled
in Promela and verified using SPIN. The verification of arbitrary system configurations is discussed.
Received July 2001/Accepted in revised form November 2002
Correspondence and offprint requests to: Alice Miller, Department of Computing Science, University of Glasgow, 17 Lilybank Gardens, Glasgow G12 8QQ, UK. Email: alice@dcs.gla.ac.uk 相似文献
45.
本文报导了采用一种新型高温陶瓷发热体高温管状炉,通以氩气保护,测量WRe合金丝的电阻-温度(1600℃)特性试验方法,该方法较真空炉简便、实用且试验费用低而准确,测量数据与美国研究报导一致。 相似文献
46.
对长石、石英、龙岩土、莱阳土4种因素各取4个水平,用正交表L16(45)安排16个试验,分析了这16个试验产品的吸水率、白度、热稳定性与每种因素各水平之间的关系.得出了白瓷坯料的最佳配方。其中,长石19,石英21,龙岩土21.莱阳土0. 相似文献
47.
Enrico Tronci 《International Journal on Software Tools for Technology Transfer (STTT)》2006,8(4-5):355-358
In today’s competitive market designing of digital systems (hardware as well as software) faces tremendous challenges. In
fact, notwithstanding an ever decreasing project budget, time to market and product lifetime, designers are faced with an
ever increasing system complexity and customer expected quality. The above situation calls for better and better formal verification
techniques at all steps of the design flow. This special issue is devoted to publishing revised versions of contributions
first presented at the 12th Advanced Research Working Conference on Correct Hardware Design and Verification Methods (CHARME) held 21–24 October 2003 in L’Aquila, Italy. Authors of well regarded papers from CHARME’03 were invited to submit
to this special issue. All papers included here have been suitably extended and have undergone an independent round of reviewing. 相似文献
48.
In this paper a methodology for the use of temporal logic as an executable imperative language is introduced. The approach, which provides a concrete framework, calledMetateM, for executing temporal formulae, is motivated and illustrated through examples. In addition, this introduction provides references to further, more detailed, work relating to theMetateM approach to executable logics. 相似文献
49.
Alessandra Lumini 《Pattern recognition》2007,40(3):1057-1065
Given the recent explosion of interest in human authentication, verification based on tokenized pseudo-random numbers and the user specific biometric feature (BioHashing) has received much attention. These methods have significant functional advantages over sole biometrics i.e. zero equal error rate. The main drawback of the base BioHashing method proposed in the literature relies in exhibiting low performance when an “impostor” B steals the pseudo-random numbers of A and he tries to authenticate as A. In this paper, we introduce some ideas to improve the base BioHashing approach in order to maintain a very low equal error rate when nobody steals the Hash key, and to reach good performance also when an “impostor” steals the Hash key. 相似文献
50.
Alessandra Lumini 《Pattern recognition》2006,39(4):714-716
We present a system for fingerprint verification that approaches the problem as a two-class pattern recognition problem. The features extracted by “FingerCode” are used to capture the ridge strength. This feature vector is then classified as genuine or impostor according to a novel approach to handle the fingerprint verification as a two-class problem. Moreover, we show that extracting the features from sub-images around the core permits to better represent the local information. 相似文献