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   64171篇
  免费   5461篇
  国内免费   2804篇
电工技术   3434篇
技术理论   3篇
综合类   3914篇
化学工业   10511篇
金属工艺   2934篇
机械仪表   3256篇
建筑科学   4473篇
矿业工程   1503篇
能源动力   1787篇
轻工业   5862篇
水利工程   1181篇
石油天然气   2546篇
武器工业   410篇
无线电   7466篇
一般工业技术   7936篇
冶金工业   5769篇
原子能技术   645篇
自动化技术   8806篇
  2024年   224篇
  2023年   1146篇
  2022年   1827篇
  2021年   2926篇
  2020年   2054篇
  2019年   1797篇
  2018年   1994篇
  2017年   2044篇
  2016年   1812篇
  2015年   2291篇
  2014年   2988篇
  2013年   3772篇
  2012年   3746篇
  2011年   4046篇
  2010年   3320篇
  2009年   3339篇
  2008年   3296篇
  2007年   3087篇
  2006年   2878篇
  2005年   2421篇
  2004年   2049篇
  2003年   2173篇
  2002年   2489篇
  2001年   2152篇
  2000年   1471篇
  1999年   1380篇
  1998年   1986篇
  1997年   1404篇
  1996年   1110篇
  1995年   791篇
  1994年   638篇
  1993年   578篇
  1992年   383篇
  1991年   287篇
  1990年   256篇
  1989年   223篇
  1988年   190篇
  1987年   163篇
  1986年   156篇
  1985年   176篇
  1984年   111篇
  1983年   108篇
  1982年   108篇
  1981年   124篇
  1980年   113篇
  1979年   78篇
  1977年   113篇
  1976年   211篇
  1975年   60篇
  1973年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Amphotericin B (AMB) was often used in intra-articular injection administration for fungal arthritis, because it could often bring a satisfactory therapeutic efficacy and a minimum systemic toxic side effect. However, because of the multiple operations and the frequent injections, the compliance of the patients was bad. Therefore, to develop a long-term sustained-released preparation of AMB for mycotic arthritis intra-articular administration is of great significance. The purpose of present study was to develop a long-term sustained-released in situ gel of a water-insoluble drug AMB for mycotic arthritis intra-articular administration. Based on the evaluations of the in vitro properties of the formulations, the formulation containing 10% (w/w) ethanol, 15% (w/w) PG, 0.75% (w/w) HA, 5% (w/w) purified soybean oil, 0.03% (w/w) α-tocopherol, 15% (w/w) water and 55% (w/w) glyceryl monooleate was selected as a suitable intra-articular injectable in situ gel drug delivery system for water-insoluble drug AMB. Furthermore, the results of the in vivo study on rabbits showed that the selected formulation was a safe and effective long-term sustained-released intra-articular injectable AMB preparation. Therefore, the presented in situ AMB gel could reduce the frequency of the administration in the AMB treatment of fungal arthritis, and then would get a good patient compliance.  相似文献   
32.
Hou  Jianhua  Ye  Jiantao 《Scientometrics》2020,124(2):1631-1662
Scientometrics - In traditional research, the application of quantitative measurement on the value and influence of uncited papers is not feasible owing to the lack of data. The rapid advancement...  相似文献   
33.
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   
34.
Sun  Yue  Zhu  Yu  Li  Ying  Zhang  Mingyu 《Wireless Personal Communications》2020,111(1):83-96
Wireless Personal Communications - The existing long term evolution networks originally designed for human-to-human communications are hard to tackle numerous and bursty random access requests from...  相似文献   
35.
In this paper, a new inverse identification method of constitutive parameters is developed from full kinematic and thermal field measurements. It consists in reconstructing the heat source field from two different approaches by using the heat diffusion equation. The first one requires the temperature field measurement and the value of the thermophysical parameters. The second one is based on the kinematic field measurement and the choice of a thermo-hyperelastic model that contains the parameters to be identified. The identification is carried out at the local scale, ie, at any point of the heat source field, without using the boundary conditions. In the present work, the method is applied to the challenging case of hyperelasticity from a heterogeneous test. Due to large deformations undergone by the rubber specimen tested, a motion compensation technique is developed to plot the kinematic and the thermal fields at the same points before reconstructing the heterogeneous heat source field. In the present case, the constitutive parameter of the Neo-Hookean model has been identified, and its distribution has been characterized with respect to the strain state at the surface of a cross-shaped specimen.  相似文献   
36.
37.
Khater  G. A.  Nabawy  Bassem S.  Kang  Junfeng  Yue  Yunlong  Mahmoud  M. A. 《SILICON》2020,12(12):2921-2940
Silicon - A total of six glass batches (WB100-WB50) based primarily on weathered basalt with successive addition of bypass cement dust (with the weight content 0–50%) were melted at...  相似文献   
38.
结合新工厂的应用经验,通过对"都林"机器人的喷涂方式、布局、雾化器配置选型、参数设置、仿形设计及品质控制要点等方面的分析,总结了连续式喷涂的优势及技术控制要求。  相似文献   
39.
为了避免回收单一钕铁硼废料中有价元素带来的操作复杂和资源浪费等问题,本研究采用共沉淀法共沉淀出钕铁硼废料中的有价元素Me(Nd,Pr,Co,Fe),制备可用于生产再生钕铁硼的原料;根据质量守恒和同时平衡原理,采用MATLAB软件建立Me(Nd,Pr,Co,Fe)-OH--NH3热力学模型,绘制lg[Me]-p H曲线模拟共沉淀工艺,并根据模拟结果确立了共沉淀工艺;模拟和实验的结果表明:根据lg[Me]-p H模拟结果可以确立一步共沉淀法的p H:6~10,Fe3+比Fe2+更易于沉淀完全;在上述条件下获得的共沉淀粉末主相均为Nd,Pr,Co,Fe的化合物,且有价元素的百分比含量均大于99.4%;其中,当p H值在8左右时回收率最高,在该条件下金属元素Me(Nd,Pr,Co,Fe)的沉淀效率分别为:98.7%,99.9%,93.6%,99.9%。该结果也表明共沉淀法工艺不仅高效,而且所制备的共沉淀粉末可以满足制备二次钕铁硼的需要。  相似文献   
40.
针对国际黄金价格的走低,黄金冶炼企业如何在激烈的市场竞争中寻求更大的利润空间,优化成本控制显得尤为重要。以某冶炼厂为例,阐述核算前移在优化企业成本控制中的应用,以达到降本增效的目的,实现企业利润的最大化。  相似文献   
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