全文获取类型
收费全文 | 4834篇 |
免费 | 184篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 39篇 |
综合类 | 5篇 |
化学工业 | 1149篇 |
金属工艺 | 82篇 |
机械仪表 | 80篇 |
建筑科学 | 215篇 |
矿业工程 | 20篇 |
能源动力 | 166篇 |
轻工业 | 366篇 |
水利工程 | 35篇 |
石油天然气 | 36篇 |
武器工业 | 2篇 |
无线电 | 430篇 |
一般工业技术 | 817篇 |
冶金工业 | 869篇 |
原子能技术 | 14篇 |
自动化技术 | 698篇 |
出版年
2023年 | 32篇 |
2022年 | 72篇 |
2021年 | 91篇 |
2020年 | 59篇 |
2019年 | 72篇 |
2018年 | 88篇 |
2017年 | 91篇 |
2016年 | 89篇 |
2015年 | 88篇 |
2014年 | 129篇 |
2013年 | 363篇 |
2012年 | 221篇 |
2011年 | 298篇 |
2010年 | 190篇 |
2009年 | 221篇 |
2008年 | 220篇 |
2007年 | 238篇 |
2006年 | 199篇 |
2005年 | 156篇 |
2004年 | 123篇 |
2003年 | 118篇 |
2002年 | 127篇 |
2001年 | 97篇 |
2000年 | 81篇 |
1999年 | 81篇 |
1998年 | 110篇 |
1997年 | 101篇 |
1996年 | 80篇 |
1995年 | 95篇 |
1994年 | 61篇 |
1993年 | 60篇 |
1992年 | 48篇 |
1991年 | 50篇 |
1990年 | 65篇 |
1989年 | 46篇 |
1988年 | 45篇 |
1987年 | 38篇 |
1986年 | 39篇 |
1985年 | 60篇 |
1984年 | 59篇 |
1983年 | 44篇 |
1982年 | 43篇 |
1981年 | 36篇 |
1980年 | 42篇 |
1979年 | 46篇 |
1978年 | 49篇 |
1977年 | 41篇 |
1976年 | 40篇 |
1975年 | 36篇 |
1973年 | 36篇 |
排序方式: 共有5023条查询结果,搜索用时 31 毫秒
1.
2.
Dr. Raysa Khan Tareque Dr. Storm Hassell-Hart Dr. Tobias Krojer Dr. Anthony Bradley Dr. Srikannathasan Velupillai Dr. Romain Talon Dr. Michael Fairhead Dr. Iain J. Day Kamlesh Bala Dr. Robert Felix Dr. Paul D. Kemmitt Prof. Paul Brennan Prof. Frank von Delft Dr. Laura Díaz Sáez Prof. Kilian Huber Prof. John Spencer 《ChemMedChem》2020,15(24):2513-2520
Combined photochemical arylation, “nuisance effect” (SNAr) reaction sequences have been employed in the design of small arrays for immediate deployment in medium-throughput X-ray protein–ligand structure determination. Reactions were deliberately allowed to run “out of control” in terms of selectivity; for example the ortho-arylation of 2-phenylpyridine gave five products resulting from mono- and bisarylations combined with SNAr processes. As a result, a number of crystallographic hits against NUDT7, a key peroxisomal CoA ester hydrolase, have been identified. 相似文献
3.
Hypoxia formation and breakdown were tracked during 2015 in Muskegon Lake estuary at multiple locations, and five years (2011–2015) of time-series buoy observatory data were evaluated for the effect of episodic wind-events on lake mixing. Bi-weekly water temperature and dissolved oxygen (DO) profiles at four locations revealed that hypoxia occurred at all sites and persisted for 2–3 months during summer 2015. On one date in late-summer, up to 24% of the lake’s volume was estimated to be mildly hypoxic (DO < 4 mg L?1) as defined by lake sturgeon requirements. Patterns of wind speed and water column stability in late spring indicated that high winds and low stability delayed the onset of hypoxia while in late summer low winds and high stability delayed degradation of hypoxia. Wind speeds appear to play a great role in the interannual variability of stratification and subsequent hypoxia. Water temperature and DO profiles taken before and after one mid-summer mixing event (wind speed >7.7 m s?1 for 10 h), indicated that while the wind was unable to completely mix the entire water column, it deepened the epilimnion by ~1.5 m and sheared a thin layer from the upper hypolimnion. By entraining internally loaded nutrients, such episodic wind-events may initiate and sustain algal blooms in nutrient limited surface waters. Quantifying the variable role of wind and mixing events will be key to integrating limnological processes into climate models of the future. 相似文献
4.
Li Zhang Huiqun Yuan Sheng-Hung Chang Anthony Lam 《The International Journal of Advanced Manufacturing Technology》2020,107(3):1081-1089
With the continuous development of the Internet of Things technology and the proposal of “Made in China 2025”, the construction of IoT applicat 相似文献
5.
6.
7.
Anthony E. Bentley 《国际强度与非线性控制杂志
》1994,4(1):119-160
》1994,4(1):119-160
Two different control systems were developed using quantitative feedback theory for weld quality improvement. The first application to be discussed was designed for the resistance pinch welding process and uses electrode displacement and force as feedback parameters. A correlation between weld quality and electrode displacement is established for constant electrode force. The system is capable of producing repeatable welds of consistent quality, with wide variations in weld parameters. This is the first time feedback control has been successfully applied to pinch welding. The second example presented in this paper was developed for penetration control of the gas-tungsten-arc welding process. The feedback signal is obtained by measuring the amount of light emitted from the back side of the weld. Welds of constant penetration have been demonstrated in tests with travel speeds varying from 1.5 to 6 inches per minute and with 200 per cent changes in part thickness. 相似文献
8.
Ipratropium bromide is a synthetic derivative of atropine with little absorption when used in inhalation, and therefore little secondary effects. The authors review its pharmacological properties and therapeutic efficacy in the treatment of asthma in children. Combined nebulized inhalation of ipratropium bromide and beta 2 sympathomimetic results in a more efficient and more sustained bronchodilatation than beta 2 sympathicomimetic alone in the treatment of acute asthma in children. Ipratropium bromide should be usefully introduced in the therapeutic scheme of acute asthma in children. Further studies will be necessary in order to determine its efficacy and tolerance in infants. 相似文献
9.
Anthony J. Calise Manu Sharma J.Eric Corban 《战术导弹控制技术》2002,(4):46-53
传统制导弹药自动驾驶仪的设计要求精确的气动模型,并依赖于变增益(gainschedule),以说明系统的非线性.本文给出了一种简化自动驾驶仪设计程序的方法:在单一飞行条件下设计逆控制器,将逆控制器与在线神经网络组合,以说明因近似逆引起的误差,这样减少了大量设计程序及精确的气动数据.这些数据在大攻角或其它情况下很重要,因为这些领域中的空气动力特征变得高度非线性化.研究发现:逆的选择在其实现的过程中很重要,所以详细讨论.最后,给出该方法在非线性6自由度制导弹药中的模拟结果. 相似文献
10.
Finkel Melinda J.; Storaasli Ragnar D.; Bandele Anthony; Schaefer Vivian 《Canadian Metallurgical Quarterly》2003,34(5):555
How can psychologists and graduate students become more affirmative of lesbian, gay, bisexual, and transgender (LGBT) issues? Safe Zone is a diversity-training program to increase sensitivity toward, knowledge of, and advocacy for LGBT populations and issues that affect them. In this exploratory study, the implementation of Safe Zone is described within a school of professional psychology; its effectiveness was assessed by self-reported behavioral and attitudinal changes and from participant evaluations. Results were encouraging with regard to the goals of Safe Zone and its adaptation to institutions interested in improving relations with the LGBT community, but additional empirical studies are needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献