首页 | 官方网站   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   277699篇
  免费   3297篇
  国内免费   701篇
工业技术   281697篇
  2022年   3769篇
  2021年   5354篇
  2020年   4011篇
  2019年   5061篇
  2018年   4496篇
  2017年   4093篇
  2016年   4027篇
  2015年   2529篇
  2014年   4225篇
  2013年   10850篇
  2012年   6648篇
  2011年   9768篇
  2010年   7698篇
  2009年   8520篇
  2008年   8207篇
  2007年   8352篇
  2006年   7600篇
  2005年   6905篇
  2004年   7711篇
  2003年   7302篇
  2002年   7268篇
  2001年   6744篇
  2000年   5980篇
  1999年   5775篇
  1998年   13112篇
  1997年   9346篇
  1996年   7078篇
  1995年   5694篇
  1994年   5259篇
  1993年   4962篇
  1992年   3984篇
  1991年   3624篇
  1990年   3825篇
  1989年   3798篇
  1988年   3555篇
  1987年   3063篇
  1986年   3213篇
  1985年   3606篇
  1984年   3365篇
  1983年   3115篇
  1982年   2929篇
  1981年   2929篇
  1980年   2793篇
  1979年   2710篇
  1978年   2860篇
  1977年   3154篇
  1976年   3950篇
  1975年   2530篇
  1974年   2361篇
  1973年   2440篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
This study was conducted to evaluate the effect of red-wine grape pomaces on the quality and sensory attributes of beef hamburger patties. Both phenolic content and antioxidant activity were assessed using Syrah, Merlot and Cabernet Sauvignon pomaces. Following the assessment, hamburger patties were prepared with Merlot pomace at 0%, 2% and 4% for the patty quality and sensory attributes. Grape seeds possessed significantly higher phenolics and antioxidant activities over the seedless pomace (P < 0.05), whereas no significant difference was found for phenolics and antioxidant activities within the seeds and seedless pomaces. The patty pH decreased as the pomace was added for 2% and 4%. Colour values (L*, a* and b*) of patties lowered as the pomace was added. Allo-Kramer shear force and hardness values increased while cooking yield decreased (P < 0.05) with the addition of pomace. No significant difference between control and Merlot patties was found for flavour, juiciness and colour, whereas lower sensory attributes were observed for texture, taste and overall acceptability. It is observed that the addition of fermented red-wine grape pomace provides hamburger patties with health promoting factors such as antioxidant and other functional components, but it also provided darker, sourer and lower cooking yield.  相似文献   
72.
Theoretical Foundations of Chemical Engineering - The corona onset voltage is an important operating parameter in the electrostatic precipitation of nanoparticulate, however, its experimental...  相似文献   
73.
Jori  Popat K.  Jadhav  Vrushali H. 《Catalysis Letters》2022,152(6):1703-1710
Catalysis Letters - A new zirconium based carbonaceous solid acid catalyst Zr@CC-PA with both Lewis and Bronsted acidic sites was prepared by simultaneous carbonization and phosphonation of glucose...  相似文献   
74.
Glass Physics and Chemistry - Composite materials (CMs) activated by silver and lanthanum ions based on high-silica porous glass (PG) matrices have been synthesized. The CMs were studied by IR...  相似文献   
75.
Glass and Ceramics - An analysis of the specific mechanisms of the influence of the state of the grain structure on the thermoelectric properties (electrical resistivity and total thermal...  相似文献   
76.
Russian Engineering Research - In practice, it is important to assess the nonuniformity of the crankshaft speed in internal combustion engines. In such assessments, the sensitivity of the chosen...  相似文献   
77.
Water Resources Management - The localization of the leaks is estimated using the time difference method in the past decade. Generalized and Basic Cross-correlation techniques are frequently...  相似文献   
78.
In the present work it is found that the pyrotechnic composition VS-2 can be initiated with flash lamps IFC-500 and EVIS. VS-2 pyrotechnic composition contains 90% of mercury(Ⅱ) 5-hydrazinotetrazolate perchlorate and 10% of optically transparent copolymer of 2-methyl-5-vinyltetrazole and methacrylic acid (PVMT). We have found that the flash lamps make it possible to initiate combustion of VS-2 composition with its transition to detonation both in cylindrical charges placed in brass caps of 5 mm diameter and 2 mm high, and film charges with 10 mm×80 mm in size and surface weights of 60 mg·cm-2 and 90 mg·cm-2, showing ignition delay times 10 μs and 3 μs, respectively. We also measured detonation velocities for VS-2 composition film charges, which were 4375-4505 m·s-1 (of the charge being surface mass 60 mg·cm-2) and 4221-4281 m·s-1 (of the charge being surface mass 90 mg·cm-2) and their blasting action on the aluminum plate. The depths of the normal shock wave imprints at the charge-barrier interface were 0.6-0.7 mm (for surface mass of the film charges 60 mg·cm-2) and 1.2-1.3 mm (for surface mass of the film charges 90 mg·cm-2).  相似文献   
79.
Wireless Personal Communications - Image transmission from space borne equipment is a challenging task owing to its restrictions on bandwidth and memory requirement. Many of the state of art...  相似文献   
80.
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   
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-23

京公网安备 11010802026262号