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   595701篇
  免费   8184篇
  国内免费   1726篇
电工技术   10947篇
综合类   547篇
化学工业   91411篇
金属工艺   23682篇
机械仪表   19318篇
建筑科学   13061篇
矿业工程   3244篇
能源动力   15905篇
轻工业   48863篇
水利工程   6126篇
石油天然气   11461篇
武器工业   44篇
无线电   68887篇
一般工业技术   117637篇
冶金工业   112182篇
原子能技术   13400篇
自动化技术   48896篇
  2021年   5546篇
  2020年   4159篇
  2019年   5304篇
  2018年   8960篇
  2017年   8999篇
  2016年   9645篇
  2015年   6102篇
  2014年   10163篇
  2013年   28391篇
  2012年   16267篇
  2011年   21989篇
  2010年   17473篇
  2009年   19512篇
  2008年   20114篇
  2007年   19873篇
  2006年   17838篇
  2005年   15846篇
  2004年   15021篇
  2003年   14785篇
  2002年   14378篇
  2001年   14091篇
  2000年   13332篇
  1999年   13743篇
  1998年   34377篇
  1997年   23799篇
  1996年   18363篇
  1995年   13850篇
  1994年   12161篇
  1993年   12133篇
  1992年   8981篇
  1991年   8387篇
  1990年   8514篇
  1989年   8068篇
  1988年   7725篇
  1987年   6774篇
  1986年   6701篇
  1985年   7611篇
  1984年   7068篇
  1983年   6384篇
  1982年   5912篇
  1981年   6061篇
  1980年   5715篇
  1979年   5516篇
  1978年   5533篇
  1977年   6237篇
  1976年   8105篇
  1975年   4796篇
  1974年   4515篇
  1973年   4667篇
  1972年   3922篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Deshmukh  P.  Sar  S. K.  Smječanin  N.  Nuhanović  M.  Lalwani  R. 《Radiochemistry》2022,64(4):532-542
Radiochemistry - Magnetically modified waste bark of the Aegle marmelos tree was prepared by using green synthesis method and was used in a batch system for U(VI) removal from aqueous solution. The...  相似文献   
42.
Kamar  M. S.  Shalan  A. S.  Youssef  W. M.  Hussein  A. E. M.  Khawassek  Y. M.  Taha  M. H. 《Radiochemistry》2022,64(2):244-256
Radiochemistry - Ferrugination, sericitization, desulfitization, chloritization, and kaolinitization of hydrothermal origin are the main wall rock alterations occurring within the NNW shear zones...  相似文献   
43.

Modern metrics for evaluating agreement coefficients between the experimental results and expert opinion are compared, and the possibility of using these metrics in experimental research in automatic text processing by machine learning methods is assessed. The choice of Cohen’s kappa coefficient as a measure of expert opinion agreement in the NLP and Text Mining problems is justified. An example of using Cohen’s kappa coefficient for evaluating the level of agreement between the opinion of an expert and the results of ML classification and the measure of agreement of expert opinions in the alignment of sentences of the Kazakh-Russian parallel corpus is given. Based on this analysis, it is proved that Cohen’s kappa coefficient is one of the best statistical methods for determining the level of agreement in experimental studies due to its ease of use, computing simplicity, and high accuracy of the results.

  相似文献   
44.
Wireless Personal Communications - Multiple inputs multiple outputs (MIMO) is a reliable technique which can manage the increased wireless data traffic in the future generation of wireless...  相似文献   
45.
Russian Engineering Research - The stability of robot-mower motion in a specific direction is considered. The direction is regulated by means of an angular sensor and a programmable controller...  相似文献   
46.
47.
This review examines the application, limitations, and potential alternatives to the Hagberg–Perten falling number (FN) method used in the global wheat industry for detecting the risk of poor end-product quality mainly due to starch degradation by the enzyme α-amylase. By viscometry, the FN test indirectly detects the presence of α-amylase, the primary enzyme that digests starch. Elevated α-amylase results in low FN and damages wheat product quality resulting in cakes that fall, and sticky bread and noodles. Low FN can occur from preharvest sprouting (PHS) and late maturity α-amylase (LMA). Moist or rainy conditions before harvest cause PHS on the mother plant. Continuously cool or fluctuating temperatures during the grain filling stage cause LMA. Due to the expression of additional hydrolytic enzymes, PHS has a stronger negative impact than LMA. Wheat grain with low FN/high α-amylase results in serious losses for farmers, traders, millers, and bakers worldwide. Although blending of low FN grain with sound wheat may be used as a means of moving affected grain through the marketplace, care must be taken to avoid grain lots from falling below contract-specified FN. A large amount of sound wheat can be ruined if mixed with a small amount of sprouted wheat. The FN method is widely employed to detect α-amylase after harvest. However, it has several limitations, including sampling variability, high cost, labor intensiveness, the destructive nature of the test, and an inability to differentiate between LMA and PHS. Faster, cheaper, and more accurate alternatives could improve breeding for resistance to PHS and LMA and could preserve the value of wheat grain by avoiding inadvertent mixing of high- and low-FN grain by enabling testing at more stages of the value stream including at harvest, delivery, transport, storage, and milling. Alternatives to the FN method explored here include the Rapid Visco Analyzer, enzyme assays, immunoassays, near-infrared spectroscopy, and hyperspectral imaging.  相似文献   
48.
Multimedia Tools and Applications - Discovering the relevant web services for specific applications in the dynamically changing business world becomes very critical. Researchers have used many...  相似文献   
49.
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic...  相似文献   
50.
Mobile Networks and Applications - 5G/6G communication are first generation high speed wireless communication network which integrates the aerial data, terrestrial data and maritime data via...  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