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   168493篇
  免费   9156篇
  国内免费   4480篇
电工技术   6483篇
技术理论   9篇
综合类   7787篇
化学工业   25795篇
金属工艺   9380篇
机械仪表   8184篇
建筑科学   8601篇
矿业工程   3009篇
能源动力   3684篇
轻工业   9344篇
水利工程   2918篇
石油天然气   4784篇
武器工业   911篇
无线电   19814篇
一般工业技术   26612篇
冶金工业   6809篇
原子能技术   1343篇
自动化技术   36662篇
  2024年   429篇
  2023年   1524篇
  2022年   3026篇
  2021年   3947篇
  2020年   2970篇
  2019年   2451篇
  2018年   16826篇
  2017年   16059篇
  2016年   12338篇
  2015年   4193篇
  2014年   4599篇
  2013年   5463篇
  2012年   8637篇
  2011年   15097篇
  2010年   13223篇
  2009年   10420篇
  2008年   11500篇
  2007年   12124篇
  2006年   4677篇
  2005年   4943篇
  2004年   3809篇
  2003年   3642篇
  2002年   3004篇
  2001年   2335篇
  2000年   2218篇
  1999年   2159篇
  1998年   1830篇
  1997年   1559篇
  1996年   1310篇
  1995年   1100篇
  1994年   822篇
  1993年   678篇
  1992年   562篇
  1991年   430篇
  1990年   305篇
  1989年   290篇
  1988年   235篇
  1987年   137篇
  1986年   118篇
  1985年   111篇
  1984年   51篇
  1983年   48篇
  1982年   60篇
  1981年   41篇
  1968年   46篇
  1966年   48篇
  1965年   50篇
  1959年   38篇
  1955年   63篇
  1954年   68篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
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   
5.
Rapid synthesis of silver nanowires(Ag NWs) with high quality and a broad processing window is challenging because of the low selectivity of the formation of multiply twinned particles at the nucleation stage for subsequent Ag NWs growth.Herein we report a systematic study of the water-involved heterogeneous nucleation of Ag NWs with high rate(less than 20 min) in a simple and scalable preparation method.Using glycerol as a reducing agent and a solvent with a high boiling point,the reaction is rapidly heated to 210 ℃ in air to synthesize Ag NWs with a very high yield in gram level.It is noted that the addition of a small dose of water plays a key role for obtaining highly pure Ag NWs in high yield,and the optimal water/glycerol ratio is0.25%.After investigating a series of forming factors including reaction temperature and dose of catalysts,the formation kinetics and mechanism of the Ag NWs are proposed.Compared to other preparation methods,our strategy is simple and reproducible.These Ag NWs show a strong Raman enhancement effect for organic molecules on their surface.  相似文献   
6.
Cases of isolated hepatic tuberculosis (TB) are rare. The diagnosis is often delayed or missed because of nonspecific symptoms and laboratory findings. Besides, the disease is extremely rare even in a country where TB is an alarming public health problem. This report demonstrates the difficulty in correctly diagnosing local hepatic TB. We report the case of a 62‐year‐old male patient with end‐stage renal disease treated with hemodialysis, who developed 2 months of abdominal distension and general anorexia, with hyperechoic hepatic lesions on ultrasound. Computed tomography suspected multiple liver tumors. The liver biopsy finally led to the diagnosis of TB of the liver without other involvements. We conclude that isolated hepatic TB is one of the rare forms of extrapulmonary TB in dialysis patients. A greater awareness of this rare clinical entity may prevent needless surgical interventions.  相似文献   
7.
Li2ZrO3-modified LiNi0.5Mn0.5O2 materials with improved electrochemical performance were directly synthesized by a simple mechanical milling route with ZrO2, Li2CO3 and Ni0.5Mn0.5(OH)2 precursors...  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