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   206573篇
  免费   29396篇
  国内免费   8684篇
电工技术   12981篇
技术理论   7篇
综合类   12165篇
化学工业   42059篇
金属工艺   10045篇
机械仪表   11698篇
建筑科学   14978篇
矿业工程   4143篇
能源动力   5849篇
轻工业   19400篇
水利工程   3925篇
石油天然气   7378篇
武器工业   1544篇
无线电   28264篇
一般工业技术   31303篇
冶金工业   8164篇
原子能技术   2118篇
自动化技术   28632篇
  2024年   652篇
  2023年   2622篇
  2022年   5105篇
  2021年   7761篇
  2020年   6467篇
  2019年   7081篇
  2018年   7525篇
  2017年   8440篇
  2016年   8485篇
  2015年   10711篇
  2014年   12373篇
  2013年   15520篇
  2012年   14413篇
  2011年   15224篇
  2010年   13905篇
  2009年   13148篇
  2008年   12544篇
  2007年   11838篇
  2006年   11139篇
  2005年   9208篇
  2004年   6822篇
  2003年   6059篇
  2002年   6308篇
  2001年   5311篇
  2000年   4728篇
  1999年   3874篇
  1998年   3051篇
  1997年   2588篇
  1996年   2306篇
  1995年   1956篇
  1994年   1555篇
  1993年   1242篇
  1992年   968篇
  1991年   740篇
  1990年   595篇
  1989年   486篇
  1988年   389篇
  1987年   268篇
  1986年   232篇
  1985年   191篇
  1984年   131篇
  1983年   89篇
  1982年   92篇
  1981年   87篇
  1980年   77篇
  1979年   50篇
  1978年   38篇
  1977年   37篇
  1976年   64篇
  1975年   23篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Lin  Haicheng  Huang  Wantong  Zhao  Kun  Qiao  Shuang  Liu  Zheng  Wu  Jian  Chen  Xi  Ji  Shuai-Hua 《Nano Research》2020,13(1):133-137
Nano Research - The isostructural and isoelectronic transition-metal-dichalcogenides 1T-TaS2 and 1T-TaSe2 are layered materials with intricate electronic structures. Combining the molecular beam...  相似文献   
52.
刘少龙  李仑升  曹琳 《电子测试》2020,(8):26-27,51
本文利用TI公司TMS320F28335芯片高效的浮点运算能力,结合片上丰富的外设,设计并实现了一种具有高可靠性的智能电源控制单元。该控制单元周期性地对各片上外设进行自检维护,完成多路负载通道控制、电压、电流的实时监控,并对故障进行指示、处理和上报,同时提供人机交互界面更新状态信息。经过验证,该控制单元工作稳定,具备良好的工程应用价值。  相似文献   
53.
Lin  Jun-You  Yang  Chih-Hai 《Scientometrics》2020,122(1):1-2
Scientometrics - University–industry R&;amp;D collaboration is a key driver of participating firms’ technological capability. However, there is still debate on the determinants of a...  相似文献   
54.
55.
56.
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications.  相似文献   
57.
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus.  相似文献   
58.
Removal of imidacloprid and acetamiprid in tea infusions by microfiltration membrane using dead‐end model was investigated in the present study. The results showed that microfiltration significantly promoted the removal of both pesticides (P < 0.05) in tea infusions. Furthermore, the extent of removal was strongly influenced by the pore size of membrane, operational pressure and the concentrations of tea infusions. The initial concentration of imidacloprid and acetamiprid showed no significant effect on their removal rates. The maximum removal rates were 79.7% for imidacloprid and 81.9% acetamiprid. The changes in major chemical components of tea infusions after microfiltration were evaluated. The results indicated that microfiltration caused no considerable changes in total polyphenols and total free amino acids, and small but statistically significant losses (6.3–18.0%) of eight catechins and three methylxanthines when filtration volume reached to 200 mL. The present study validated the application of microfiltration as a potentially feasible and promising method for the removal of imidacloprid and acetamiprid residues from tea infusions.  相似文献   
59.
Vertical arrays of nanostructures (NSs) are emerging as promising platforms for probing and manipulating live mammalian cells. The broad range of applications requires different types of interfaces, but cell settling on NS arrays is not yet fully controlled and understood. Cells are both seen to deform completely into NS arrays and to stay suspended like tiny fakirs, which have hitherto been explained with differences in NS spacing or density. Here, a better understanding of this phenomenon is provided by using a model that takes into account the extreme membrane deformation needed for a cell to settle into a NS array. It is shown that, in addition to the NS density, cell settling depends strongly on the dimensions of the single NS, and that the settling can be predicted for a given NS array geometry. The predictive power of the model is confirmed by experiments and good agreement with cases from the literature. Furthermore, the influence of cell‐related parameters is evaluated theoretically and a generic method of tuning cell settling through surface coating is demonstrated experimentally. These findings allow a more rational design of NS arrays for the numerous exciting biological applications where the mode of cell settling is crucial.  相似文献   
60.
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