全文获取类型
收费全文 | 1525509篇 |
免费 | 29628篇 |
国内免费 | 6993篇 |
学科分类
工业技术 | 1562130篇 |
出版年
2021年 | 15790篇 |
2020年 | 12689篇 |
2019年 | 15565篇 |
2018年 | 16046篇 |
2017年 | 15202篇 |
2016年 | 22470篇 |
2015年 | 18361篇 |
2014年 | 30391篇 |
2013年 | 90093篇 |
2012年 | 38828篇 |
2011年 | 51664篇 |
2010年 | 44409篇 |
2009年 | 52479篇 |
2008年 | 47413篇 |
2007年 | 44089篇 |
2006年 | 46966篇 |
2005年 | 40983篇 |
2004年 | 43280篇 |
2003年 | 43106篇 |
2002年 | 39915篇 |
2001年 | 36597篇 |
2000年 | 34124篇 |
1999年 | 33582篇 |
1998年 | 45508篇 |
1997年 | 39067篇 |
1996年 | 34331篇 |
1995年 | 31320篇 |
1994年 | 29307篇 |
1993年 | 28793篇 |
1992年 | 26112篇 |
1991年 | 23316篇 |
1990年 | 23602篇 |
1989年 | 22563篇 |
1988年 | 21053篇 |
1987年 | 19369篇 |
1986年 | 18893篇 |
1985年 | 22271篇 |
1984年 | 22373篇 |
1983年 | 20224篇 |
1982年 | 19127篇 |
1981年 | 19170篇 |
1980年 | 17824篇 |
1979年 | 18474篇 |
1978年 | 17685篇 |
1977年 | 17749篇 |
1976年 | 19320篇 |
1975年 | 15882篇 |
1974年 | 15448篇 |
1973年 | 15524篇 |
1972年 | 13084篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Radiochemistry - The sorption extraction of Pu and Am from nitric acid simulation solutions were studied on a solid extractant (TVEX) AXIONIT MND 40T in a static mode. It is shown that the... 相似文献
72.
73.
74.
75.
Food Science and Biotechnology - The fourth industrial revolution represented by big data and artificial intelligence (AI), already had a significant impact on the food industry. In this review,... 相似文献
76.
Cybernetics and Systems Analysis - A new information software technology has been created, which is implemented in a software package and is destined to perform a wide, easily supplemented set of... 相似文献
77.
Kathleen T. Lauser Amy L. Rueter Michelle A. Calabrese 《American Institute of Chemical Engineers》2022,68(12):e17850
While protein medications are promising for treatment of cancer and autoimmune diseases, challenges persist in terms of development and injection stability of high-concentration formulations. Here, the extensional flow properties of protein-excipient solutions are examined via dripping-onto-substrate extensional rheology, using a model ovalbumin (OVA) protein and biocompatible excipients polysorbate 20 (PS20) and 80 (PS80). Despite similar PS structures, differences in extensional flow are observed based on PS identity in two regimes: at moderate total concentrations where surface tension differences drive changes in extensional flow behavior, and at small PS:OVA ratios, which impact the onset of weakly elastic flow behavior. Undesirable elasticity is observed in ultra-concentrated formulations, independent of PS identity; higher PS contents are required to observe these effects than in analogous polymeric excipient solutions. These studies reveal novel extensional flow behaviors in protein-excipient solutions, and provide a straightforward methodology for assessing the extensional flow stability of new protein-excipient formulations. 相似文献
78.
Hydrogenation of CO2 to Hydrocarbons over Zirconia-Supported Cobalt Catalyst Promoted with Potassium
Catalysis Letters - The purpose of this study was to investigate the promotive effect of potassium on the catalytic performance and properties of Co/ZrO2 catalysts during hydrogenation of CO2 to... 相似文献
79.
El-Shafiey Mohamed G. Hagag Ahmed El-Dahshan El-Sayed A. Ismail Manal A. 《Multimedia Tools and Applications》2022,81(13):18155-18179
Multimedia Tools and Applications - Nowadays, heart diseases are significantly contributing to deaths all over the world. Thus, heart-disease prediction has garnered considerable attention in the... 相似文献
80.
Zagidullin S. Kh. Dolganov V. L. Lozhkin I. G. 《Chemical and Petroleum Engineering》2022,57(9-10):765-769
Chemical and Petroleum Engineering - The hydrodynamics of oxidation towers used for bitumen production were studied using a model tower having transparent walls. Experiments were carried out in two... 相似文献