全文获取类型
收费全文 | 7852篇 |
免费 | 461篇 |
国内免费 | 51篇 |
专业分类
电工技术 | 94篇 |
综合类 | 31篇 |
化学工业 | 2000篇 |
金属工艺 | 253篇 |
机械仪表 | 304篇 |
建筑科学 | 269篇 |
矿业工程 | 20篇 |
能源动力 | 350篇 |
轻工业 | 490篇 |
水利工程 | 116篇 |
石油天然气 | 81篇 |
武器工业 | 3篇 |
无线电 | 704篇 |
一般工业技术 | 1484篇 |
冶金工业 | 823篇 |
原子能技术 | 60篇 |
自动化技术 | 1282篇 |
出版年
2024年 | 24篇 |
2023年 | 84篇 |
2022年 | 136篇 |
2021年 | 301篇 |
2020年 | 308篇 |
2019年 | 358篇 |
2018年 | 461篇 |
2017年 | 405篇 |
2016年 | 392篇 |
2015年 | 258篇 |
2014年 | 416篇 |
2013年 | 732篇 |
2012年 | 500篇 |
2011年 | 521篇 |
2010年 | 380篇 |
2009年 | 393篇 |
2008年 | 255篇 |
2007年 | 230篇 |
2006年 | 175篇 |
2005年 | 128篇 |
2004年 | 138篇 |
2003年 | 108篇 |
2002年 | 107篇 |
2001年 | 91篇 |
2000年 | 82篇 |
1999年 | 95篇 |
1998年 | 132篇 |
1997年 | 87篇 |
1996年 | 79篇 |
1995年 | 69篇 |
1994年 | 62篇 |
1993年 | 79篇 |
1992年 | 65篇 |
1991年 | 55篇 |
1990年 | 51篇 |
1989年 | 59篇 |
1988年 | 46篇 |
1987年 | 31篇 |
1986年 | 39篇 |
1985年 | 40篇 |
1984年 | 46篇 |
1983年 | 39篇 |
1982年 | 28篇 |
1981年 | 26篇 |
1980年 | 31篇 |
1978年 | 22篇 |
1977年 | 27篇 |
1976年 | 32篇 |
1974年 | 20篇 |
1973年 | 24篇 |
排序方式: 共有8364条查询结果,搜索用时 8 毫秒
1.
Effect of gums on viability and β‐galactosidase activity of Lactobacillus spp. in milk drink during refrigerated storage 下载免费PDF全文
Bernice D. Karlton‐Senaye Reza Tahergorabi Valerie L. Giddings Salam A. Ibrahim 《International Journal of Food Science & Technology》2015,50(1):32-40
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus. 相似文献
2.
3.
4.
Using Web resources to construct multilingual medical thesaurus for cross-language medical information retrieval 总被引:1,自引:0,他引:1
Due to the language barrier, non-English users are unable to retrieve the most updated medical information from the U.S. authoritative medical websites, such as PubMed and MedlinePlus. However, currently, there is no any cross-language medical information retrieval (CLMIR) system that can help Chinese-speaking consumers cross the language barrier in finding useful English medical information. A few CLMIR systems utilize MeSH (Medical Subject Headings) to help overcome the language barrier. Unfortunately, the traditional Chinese version of MeSH is currently unavailable.In this paper, we employ a semi-automatic term translation method to construct a Chinese–English MeSH by exploiting abundant multilingual Web resources, including Web anchor texts and search–result pages. Through this method, we have developed a Chinese–English Mesh Compilation System to assist knowledge engineers in compiling a Chinese–English medical thesaurus with more than 19,000 entries. Furthermore, this thesaurus has been used to develop a prototypical system for cross-language medical information retrieval, MMODE, which can help consumers retrieve top-quality English medical information using Chinese terms. 相似文献
5.
6.
M. Reza Ziai
Dileep R. Sule
《Computers & Industrial Engineering》1991,21(1-4):385-389The paper describes a computerized facility layout designer, COMLAD II, for plant layout development. Besides developing an efficient layout, COMLAD II has useful features which allow fixing the departments, changing the shape of the departments and changing the length and width dimensions of the overall layout. 相似文献
7.
M Manickam M Ramanathan MA Jahromi JP Chansouria AB Ray 《Canadian Metallurgical Quarterly》1997,60(6):609-610
Glucose levels in rats with hyperglycemia induced by streptozotocin were determined after i.p. administration of marsupsin (1), pterosupin (2), and pterostilbene (3), three important phenolic constituents of the heartwood of Pterocarpus marsupium. Marsupsin and pterostilbene significantly lowered the blood glucose level of hyperglycemic rats, and the effect was comparable to that of 1,1-dimethylbiguanide (metformin). 相似文献
8.
The corrosion behaviour of nitrogen-containing austenitic stainless steel in methanol containing different concentrations
of H2SO4, HCl, LiCl and H2SO4 + HCl has been investigated using a potentiostatic polarization method. The cathodic reaction in the H2SO4, HCl and H2SO4 + HCl solutions was proton reduction whereas in the neutral LiCl solution, oxygen reduction was the predominant cathodic
reaction. Active, passive and transpassive behaviours were observed only for higher concentrations of H2SO4 (0.01–2.0 M) due to the inherent water content. A cathodic loop, characterized by measured negative current in the anodic
region, was also observed in solutions, in which the concentration of H2SO4 was 1.0 M or higher. The relative stability of the passive films decreased as the H2SO4 concentration increased, and thus the steel suffered from mild pitting corrosion. In the chloride environment, the rate of
corrosion increased as the Cl− ion concentration increased. The presence of acid along with Cl− ions enhanced corrosion, and the corrosion rate increased significantly. The steel suffered from mild intergranular corrosion
in acidic chloride solutions of methanol. In the H2SO4 + HCl solutions, passive films were only formed when the H2SO4 to HCl concentration ratio was greater than ∼10:1. 相似文献
9.
10.
A series of experiments were carried out on three commercial steels to explore the possibility for characterizing tempered martensite embrittlement (TME) by Rockwell, macro-, and micro-Vickers hardness tests. The results indicate distinct hardness peaks in two steels and an inflection in the other around the TME temperature. A new analytical approach for examining the slope of hardness-tempering temperature plots appears to reveal the TME phenomenon more sensitively. Dilatometric examinations substantiate that the temperature of hardness peak/inflection occurs beyond the second stage of tempering. 相似文献