全文获取类型
收费全文 | 601990篇 |
免费 | 8973篇 |
国内免费 | 1865篇 |
专业分类
电工技术 | 10252篇 |
综合类 | 2822篇 |
化学工业 | 88850篇 |
金属工艺 | 24444篇 |
机械仪表 | 18105篇 |
建筑科学 | 14695篇 |
矿业工程 | 2803篇 |
能源动力 | 15564篇 |
轻工业 | 50287篇 |
水利工程 | 6394篇 |
石油天然气 | 9657篇 |
武器工业 | 37篇 |
无线电 | 68568篇 |
一般工业技术 | 116497篇 |
冶金工业 | 105878篇 |
原子能技术 | 10776篇 |
自动化技术 | 67199篇 |
出版年
2022年 | 3159篇 |
2021年 | 4891篇 |
2020年 | 3479篇 |
2019年 | 4557篇 |
2018年 | 21322篇 |
2017年 | 20101篇 |
2016年 | 17305篇 |
2015年 | 6113篇 |
2014年 | 9425篇 |
2013年 | 24201篇 |
2012年 | 17502篇 |
2011年 | 28912篇 |
2010年 | 23441篇 |
2009年 | 22858篇 |
2008年 | 24350篇 |
2007年 | 24971篇 |
2006年 | 15604篇 |
2005年 | 15296篇 |
2004年 | 14614篇 |
2003年 | 14467篇 |
2002年 | 13127篇 |
2001年 | 12913篇 |
2000年 | 12029篇 |
1999年 | 12643篇 |
1998年 | 32856篇 |
1997年 | 22918篇 |
1996年 | 17485篇 |
1995年 | 13041篇 |
1994年 | 11292篇 |
1993年 | 10980篇 |
1992年 | 7922篇 |
1991年 | 7439篇 |
1990年 | 7261篇 |
1989年 | 7013篇 |
1988年 | 6476篇 |
1987年 | 5766篇 |
1986年 | 5655篇 |
1985年 | 6265篇 |
1984年 | 5900篇 |
1983年 | 5170篇 |
1982年 | 4900篇 |
1981年 | 4966篇 |
1980年 | 4705篇 |
1979年 | 4609篇 |
1978年 | 4408篇 |
1977年 | 5334篇 |
1976年 | 6971篇 |
1975年 | 3796篇 |
1974年 | 3550篇 |
1973年 | 3665篇 |
排序方式: 共有10000条查询结果,搜索用时 34 毫秒
81.
82.
83.
84.
85.
86.
87.
M. R. Thompson 《Drug development and industrial pharmacy》2015,41(8):1223-1231
Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique. 相似文献
88.
Sergey Bombin Mitchell LeFebvre Jennifer Sherwood Yaolin Xu Yuping Bao Katrina M. Ramonell 《International journal of molecular sciences》2015,16(10):24174-24193
Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here, we investigated the effects of positive (PC) and negative (NC) charged iron oxide (Fe2O3) nanoparticles (IONPs) on the physiology and reproductive capacity of Arabidopsis thaliana at concentrations of 3 and 25 mg/L. The 3 mg/L treated plants did not show evident effects on seeding and root length. However, the 25 mg/L treatment resulted in reduced seedling (positive-20% and negative-3.6%) and root (positive-48% and negative-negligible) length. Interestingly, treatment with polyethylenimine (PEI; IONP-PC coating) also resulted in reduced root length (39%) but no change was observed with polyacrylic acid (PAA; IONP-NC coating) treatment alone. However, treatment with IONPs at 3 mg/L did lead to an almost 5% increase in aborted pollen, a 2%–6% reduction in pollen viability and up to an 11% reduction in seed yield depending on the number of treatments. Interestingly, the treated plants did not show any observable phenotypic changes in overall size or general plant structure, indicating that environmental nanoparticle contamination could go dangerously unnoticed. 相似文献
89.
90.