全文获取类型
收费全文 | 284645篇 |
免费 | 6252篇 |
国内免费 | 1073篇 |
专业分类
电工技术 | 4552篇 |
综合类 | 229篇 |
化学工业 | 43286篇 |
金属工艺 | 8805篇 |
机械仪表 | 7887篇 |
建筑科学 | 7862篇 |
矿业工程 | 600篇 |
能源动力 | 7911篇 |
轻工业 | 33051篇 |
水利工程 | 2419篇 |
石油天然气 | 2004篇 |
武器工业 | 9篇 |
无线电 | 35358篇 |
一般工业技术 | 52076篇 |
冶金工业 | 54316篇 |
原子能技术 | 3543篇 |
自动化技术 | 28062篇 |
出版年
2022年 | 1334篇 |
2021年 | 2545篇 |
2020年 | 1972篇 |
2019年 | 2244篇 |
2018年 | 3842篇 |
2017年 | 3852篇 |
2016年 | 4191篇 |
2015年 | 3107篇 |
2014年 | 4817篇 |
2013年 | 14273篇 |
2012年 | 8736篇 |
2011年 | 11480篇 |
2010年 | 8890篇 |
2009年 | 9702篇 |
2008年 | 10444篇 |
2007年 | 10247篇 |
2006年 | 9268篇 |
2005年 | 8290篇 |
2004年 | 7984篇 |
2003年 | 7778篇 |
2002年 | 7202篇 |
2001年 | 7368篇 |
2000年 | 6684篇 |
1999年 | 7281篇 |
1998年 | 18743篇 |
1997年 | 12812篇 |
1996年 | 9560篇 |
1995年 | 7139篇 |
1994年 | 6198篇 |
1993年 | 6048篇 |
1992年 | 4176篇 |
1991年 | 3954篇 |
1990年 | 3742篇 |
1989年 | 3561篇 |
1988年 | 3441篇 |
1987年 | 2735篇 |
1986年 | 2647篇 |
1985年 | 3337篇 |
1984年 | 2953篇 |
1983年 | 2672篇 |
1982年 | 2484篇 |
1981年 | 2550篇 |
1980年 | 2341篇 |
1979年 | 2156篇 |
1978年 | 1983篇 |
1977年 | 2343篇 |
1976年 | 3076篇 |
1975年 | 1660篇 |
1974年 | 1551篇 |
1973年 | 1632篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Romero-Garcés A. Salles De Freitas R. Marfil R. Vicente-Chicote C. Martínez J. Inglés-Romero J. F. Bandera A. 《Multimedia Tools and Applications》2022,81(3):3603-3628
Multimedia Tools and Applications - The design of robots capable of operating autonomously in changing and unstructured environments, requires using complex software architectures in which,... 相似文献
22.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
23.
Nicolas Larché Benoit Emo Audrey Allion Elisabeth Johansson Dominique Thierry 《工业材料与腐蚀》2021,72(8):1338-1349
With lower alloying cost and higher mechanical properties, lean duplex stainless steels can be an alternative to the more commonly used austenitic stainless steels. However, these alloys are still not the preferred choice, probably due to a lack of field experience. A study was thus initiated in view of defining the limits of use of selected (lean) duplexes for urban wastewater treatment units. The present paper shows the localized corrosion performance of selected lean duplexes in chloride contaminated solutions. The results are compared with austenitic S30403 and S31603 and with the more standard duplexes S82441 and S32205. The effect of welding was also investigated. Exposures in field municipal wastewater plants were conducted for 1 year in low and high chloride content units. The results show that lean duplexes S32101 and S32202 can be used as alternatives to S30403 and S31603 in low chloride electrolytes. At 500 ppm of chloride content, duplex stainless steel S32304 showed better corrosion resistance than S30403 and S31603. For higher chloride contents (1000 ppm and above) the standard duplexes S82441 and S32205 shall be preferred. 相似文献
24.
Carolyn A. Grimley Stephen Funni Christopher Green Elizabeth C. Dickey 《Journal of the European Ceramic Society》2021,41(4):2807-2817
In flash sintering experiments, the thermal history of the sample is key to understanding the mechanisms underlying densification rate and final properties. By combining robust temperature measurements with current-ramp-rate control, this study examined the effects of the thermal profile on the flash sintering of yttria-stabilized zirconia, with experiments ranging from a few seconds to several hours. The final density was maximized at slower heating rates, although processes slower than a certain threshold led to grain growth. The amount of grain growth observed was comparable to a similar conventional thermal process. The bulk electrical conductivity correlated with the maximum temperature and cooling rate. The only property that exhibited behavior that could not be attributed to solely the thermal profile was the grain boundary conductivity, which was consistently higher than conventional in flash sintered samples. These results suggest that, during flash sintering, athermal electric field effects are relegated to the grain boundary. 相似文献
25.
Erwan Diler Vanessa Leblanc Hervé Gueuné Nicolas Larché Valerie Deydier Yannick Linard Didier Crusset Dominique Thierry 《工业材料与腐蚀》2021,72(1-2):218-234
In the context of the high-level radioactive waste disposal CIGEO, the corrosion rate due to microbially influenced corrosion (MIC) has to be evaluated. In France, it is envisaged to dispose of high- and intermediate-level long-lived radioactive waste at a depth of 500 m in a deep geological disposal, drilled in the Callovo-Oxfordian claystone (Cox) formation. To do so, a carbon steel casing will be inserted inside disposal cells, which are horizontal tunnels drilled in the Cox. A specific cement grout will be injected between the carbon steel casing and the claystone. A study was conducted to evaluate the possibility of MIC on carbon steel in the foreseeable high radioactive waste disposal. The corrosiveness of various environments was investigated at 50°C and 80°C with or without microorganisms enriched from samples of Andra's underground research laboratory. The monitoring of corrosion during the experiments was ensured using gravimetric method and real-time corrosion monitoring using sensors based on the measurements of the electrical resistance. The corrosion data were completed with microbiological analyses including cultural and molecular characterizations. 相似文献
26.
L.J. Espinoza-Pérez S. Esquivel-Medina E. López-Honorato 《Ceramics International》2021,47(11):15527-15532
The influence of the microstructure on the corrosion rate of three monolithic SiC samples in FLiNaK salt at 900 °C for 250 h was studied. The SiC samples, labeled as SiC-1, SiC-2, and SiC-3, had corrosion rates of 0.137, 0.020, and 0.043 mg/cm2h, respectively. Compared with grain size and the presence of special grain boundaries (i.e., Σ3), the content of high-angle grain boundaries (HAGBs) appeared to have the strongest influence on the corrosion rate of SiC in FLiNaK salt, since the corrosion rate increased six times as the concentration of high-angle grain boundaries increased from 19 to 32% for SiC-2 and SiC-1, respectively. These results stress the importance of controlling the content of HAGBs during the production process of SiC. 相似文献
27.
Tuladhar Sanira Alsadoon Abeer Prasad P. W. C. Ali Akbas Ezaldeen Alrubaie Ahmad 《Multimedia Tools and Applications》2022,81(17):23845-23865
Multimedia Tools and Applications - Gastrointestinal stromal tumor is one of the critical tumors that doctors do not suggest to get frequent endoscopy, so there is a need for a diagnosis system... 相似文献
28.
Norfariza Jamaluddin David C. Stuckey Arbakariya B. Ariff 《Critical reviews in food science and nutrition》2018,58(14):2453-2465
ABSTRACTBacteriocin is a proteinaceous biomolecule produced by bacteria (both Gram-positive and Gram-negative) that exhibits antimicrobial activity against closely related species, and food-borne pathogens. It has recently gained importance and attracted the attention of several researchers looking to produce it from various substrates and bacterial strains. This ushers in a new era of food preservation where the use of bacteriocin in food products will be an alternative to chemical preservatives, and heat treatment which are understood to cause unwanted side effects, and reduce sensory and nutritional quality. However, this new market depends on the success of novel downstream separation schemes from various types of crude feedstocks which are both effective and economic. This review focuses on the downstream separation of bacteriocin from various sources using both conventional and novel techniques. Finally, recommendations for future interesting areas of research that need to be pursued are highlighted. 相似文献
29.
Gomes A. C. S. A. Costa L. C. Brito D. C. Frana R. J. Marques Mnica R. C. 《Polymer Bulletin》2020,77(4):1969-1981
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with... 相似文献
30.
Michael A. Clegg Prof. Nicholas C. O. Tomkinson Dr. Rab K. Prinjha Dr. Philip G. Humphreys 《ChemMedChem》2019,14(4):362-385
The bromodomain and extra terminal (BET) family of bromodomain-containing proteins (BCPs) have been the subject of extensive research over the past decade, resulting in a plethora of high-quality chemical probes for their tandem bromodomains. In turn, these chemical probes have helped reveal the profound biological role of the BET bromodomains and their role in disease, ultimately leading to a number of molecules in active clinical development. However, the BET subfamily represents just 8/61 of the known human bromodomains, and attention has now expanded to the biological role of the remaining 53 non-BET bromodomains. Rapid growth of this research area has been accompanied by a greater understanding of the requirements for an effective bromodomain chemical probe and has led to a number of new non-BET bromodomain chemical probes being developed. Advances since December 2015 are discussed, highlighting the strengths/caveats of each molecule, and the value they add toward validating the non-BET bromodomains as tractable therapeutic targets. 相似文献