首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   55914篇
  免费   3430篇
  国内免费   78篇
电工技术   384篇
综合类   49篇
化学工业   11862篇
金属工艺   1088篇
机械仪表   1180篇
建筑科学   1833篇
矿业工程   121篇
能源动力   1728篇
轻工业   10084篇
水利工程   580篇
石油天然气   252篇
武器工业   3篇
无线电   2470篇
一般工业技术   8873篇
冶金工业   10718篇
原子能技术   320篇
自动化技术   7877篇
  2023年   470篇
  2022年   498篇
  2021年   1501篇
  2020年   1246篇
  2019年   1410篇
  2018年   2086篇
  2017年   2074篇
  2016年   2225篇
  2015年   1710篇
  2014年   2184篇
  2013年   4367篇
  2012年   3343篇
  2011年   3569篇
  2010年   2781篇
  2009年   2637篇
  2008年   2496篇
  2007年   2213篇
  2006年   1694篇
  2005年   1427篇
  2004年   1328篇
  2003年   1176篇
  2002年   1042篇
  2001年   736篇
  2000年   639篇
  1999年   742篇
  1998年   3517篇
  1997年   2291篇
  1996年   1543篇
  1995年   889篇
  1994年   730篇
  1993年   752篇
  1992年   282篇
  1991年   262篇
  1990年   217篇
  1989年   233篇
  1988年   232篇
  1987年   215篇
  1986年   176篇
  1985年   231篇
  1984年   166篇
  1983年   133篇
  1982年   148篇
  1981年   175篇
  1980年   170篇
  1979年   82篇
  1978年   82篇
  1977年   276篇
  1976年   517篇
  1975年   78篇
  1973年   82篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
Journal of Materials Science: Materials in Electronics - Non-volatile organic memory devices were fabricated using polystyrene sulfonate (PSS)?+?nitrogen-doped multi-walled carbon...  相似文献   
2.
3.
Scientometrics - Consolidation of the scientific activity in Latin American research centers has been a matter of serious concern in recent years. In the present study we use a data set of the WoS...  相似文献   
4.
Brito  Claúdia  Esteves  Marisa  Peixoto  Hugo  Abelha  António  Machado  José 《Wireless Networks》2022,28(3):1269-1277
Wireless Networks - Continuous ambulatory peritoneal dialysis (CAPD) is a treatment used by patients in the end-stage of chronic kidney diseases. Those patients need to be monitored using blood...  相似文献   
5.
The study aims to evaluate the technological properties of autochthonous strains (Lactobacillus sakei S15, Lactobacillus plantarum S24, L. plantarum S91, Pediococcus pentosaceus S128b and Staphylococcus carnosus G109) in Turkish dry fermented sausage (sucuk). After 24 h of fermentaPtion, all lactic acid bacteria strains reduced the pH to below 5.0, while the pH in the control group was above 5.3. The number of lactic acid bacteria strains reached 108–109 cfu g−1 during fermentation. Staphylococcus carnosus G109 remained at the inoculation level of 106 cfu g−1 during ripening. Lactobacillus sakei S15 as mono-culture showed higher TBARS values compared to other strains. The control group had the lowest L* value and autochthonous strains caused no significant difference for a* value. According to principal component analysis results, most volatile compounds were positively correlated with the group containing only L. sakei S15.  相似文献   
6.
Food- and waterborne viruses, such as human norovirus, hepatitis A virus, hepatitis E virus, rotaviruses, astroviruses, adenoviruses, and enteroviruses, are major contributors to all foodborne illnesses. Their small size, structure, and ability to clump and attach to inanimate surfaces make viruses challenging to reduce or eliminate, especially in the presence of inorganic or organic soils. Besides traditional wet and dry methods of disinfection using chemicals and heat, emerging physical nonthermal decontamination techniques (irradiation, ultraviolet, pulsed light, high hydrostatic pressure, cold atmospheric plasma, and pulsed electric field), novel virucidal surfaces, and bioactive compounds are examined for their potential to inactivate viruses on the surfaces of foods or food contact surfaces (tools, equipment, hands, etc.). Every disinfection technique is discussed based on its efficiency against viruses, specific advantages and disadvantages, and limitations. Structure, genomic organization, and molecular biology of different virus strains are reviewed, as they are key in determining these techniques effectiveness in controlling all or specific foodborne viruses. Selecting suitable viral decontamination techniques requires that their antiviral mechanism of action and ability to reduce virus infectivity must be taken into consideration. Furthermore, details about critical treatments parameters essential to control foodborne viruses in a food production environment are discussed, as they are also determinative in defining best disinfection and hygiene practices preventing viral infection after consuming a food product.  相似文献   
7.
8.
9.
Walnut flour (WF), a by-product of walnut oil production, is characterised by high polyunsaturated fatty acids, proteins, and fibre contents and presents suitability for bakery products. However, when using non-traditional ingredients, it is essential to evaluate the effect on the quality properties of the final product. So, this work aimed to assess the impact of WF on the technological, physicochemical, and sensory properties of gluten-free (GF) cakes. WF was added at a flour blend (cassava (CS) and maize (MS) starches and rice flour) at 0, 10%, 15%, and 20%. The results showed that WF modified starch gelatinisation, increased amylose–lipid complex (ALC) content, and made crumbs easier to chew. Besides, the total dietary fibre (TDF) and protein content significantly increased. Cakes with 15% WF presented the highest specific volume (SV) and no differences in overall acceptability with respect to control. Hence, WF is a suitable ingredient for gluten-free bakery products.  相似文献   
10.
Flow phenomena of three-dimensional conducting Casson fluid through a stretching sheet are proposed in the present investigation with the impact of the magnetic parameter in a permeable medium. The adaptation of particular transformations is useful to modify the governing equations into their nondimensional as well as the ordinary form. However, these transformed equations are nonlinear and approximate analytical methods for the solution of the complex form of governing equations. In particular, the Adomian decomposition method is proposed for the solution. The behavior of several variables, such as the magnetic and porous matrix, on the flow profile as well as the rate of shear stress, are discussed via graphs and tables. The conformity of the current result with the earlier study shows a road map for further investigation. The major concluding remarks are; the retardation in the velocity distribution is rendered due to an increase in the Casson parameter moreover, the Casson parameter favors in reducing the rate of shear stress coefficient in magnitude.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号