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   275200篇
  免费   5744篇
  国内免费   2364篇
电工技术   6147篇
技术理论   6篇
综合类   2146篇
化学工业   44454篇
金属工艺   11744篇
机械仪表   8654篇
建筑科学   8033篇
矿业工程   2103篇
能源动力   6032篇
轻工业   26630篇
水利工程   3133篇
石油天然气   6920篇
武器工业   317篇
无线电   29542篇
一般工业技术   51022篇
冶金工业   47884篇
原子能技术   5783篇
自动化技术   22758篇
  2021年   3096篇
  2020年   2122篇
  2019年   2475篇
  2018年   3785篇
  2017年   3835篇
  2016年   4079篇
  2015年   3343篇
  2014年   5266篇
  2013年   12266篇
  2012年   8568篇
  2011年   11122篇
  2010年   8983篇
  2009年   9457篇
  2008年   10302篇
  2007年   10323篇
  2006年   9217篇
  2005年   8102篇
  2004年   7112篇
  2003年   6629篇
  2002年   6668篇
  2001年   6694篇
  2000年   6311篇
  1999年   6299篇
  1998年   13191篇
  1997年   9812篇
  1996年   7540篇
  1995年   5755篇
  1994年   5266篇
  1993年   5061篇
  1992年   4040篇
  1991年   3852篇
  1990年   3888篇
  1989年   3821篇
  1988年   3557篇
  1987年   3044篇
  1986年   3063篇
  1985年   3419篇
  1984年   3327篇
  1983年   3085篇
  1982年   2704篇
  1981年   2904篇
  1980年   2650篇
  1979年   2840篇
  1978年   2736篇
  1977年   2841篇
  1976年   3693篇
  1975年   2457篇
  1974年   2290篇
  1973年   2320篇
  1972年   1981篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Qin  Yi  Tao  Xianping  Huang  Yu    Jian 《World Wide Web》2019,22(1):1-37
World Wide Web - Rule mechanism has been widely used in many areas, such as databases, artificial intelligent and pervasive computing. In a rule mechanism, rule activation decides which rules are...  相似文献   
2.
3.
4.
5.
Yang  Xi  Gao  Ling  Guo  Qing  Li  Yongjiang  Ma  Yue  Yang  Ju  Gong  Changyang  Yi  Cheng 《Nano Research》2020,13(10):2579-2594

Over the past decade, numerous studies have attempted to enhance the effectiveness of radiotherapy (external beam radiotherapy and internal radioisotope therapy) for cancer treatment. However, the low radiation absorption coefficient and radiation resistance of tumors remain major critical challenges for radiotherapy in the clinic. With the development of nanomedicine, nanomaterials in combination with radiotherapy offer the possibility to improve the efficiency of radiotherapy in tumors. Nanomaterials act not only as radiosensitizers to enhance radiation energy, but also as nanocarriers to deliver therapeutic units in combating radiation resistance. In this review, we discuss opportunities for a synergistic cancer therapy by combining radiotherapy based on nanomaterials designed for chemotherapy, photodynamic therapy, photothermal therapy, gas therapy, genetic therapy, and immunotherapy. We highlight how nanomaterials can be utilized to amplify antitumor radiation responses and describe cooperative enhancement interactions among these synergistic therapies. Moreover, the potential challenges and future prospects of radio-based nanomedicine to maximize their synergistic efficiency for cancer treatment are identified.

  相似文献   
6.
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   
7.
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   
8.
9.
10.
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