全文获取类型
收费全文 | 2523篇 |
免费 | 41篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 32篇 |
综合类 | 2篇 |
化学工业 | 371篇 |
金属工艺 | 32篇 |
机械仪表 | 38篇 |
建筑科学 | 169篇 |
矿业工程 | 31篇 |
能源动力 | 82篇 |
轻工业 | 182篇 |
水利工程 | 10篇 |
石油天然气 | 27篇 |
无线电 | 201篇 |
一般工业技术 | 301篇 |
冶金工业 | 670篇 |
原子能技术 | 25篇 |
自动化技术 | 400篇 |
出版年
2021年 | 17篇 |
2020年 | 12篇 |
2019年 | 27篇 |
2018年 | 21篇 |
2017年 | 31篇 |
2016年 | 29篇 |
2015年 | 25篇 |
2014年 | 29篇 |
2013年 | 160篇 |
2012年 | 67篇 |
2011年 | 71篇 |
2010年 | 69篇 |
2009年 | 66篇 |
2008年 | 80篇 |
2007年 | 86篇 |
2006年 | 104篇 |
2005年 | 90篇 |
2004年 | 85篇 |
2003年 | 93篇 |
2002年 | 69篇 |
2001年 | 47篇 |
2000年 | 47篇 |
1999年 | 66篇 |
1998年 | 180篇 |
1997年 | 114篇 |
1996年 | 95篇 |
1995年 | 70篇 |
1994年 | 56篇 |
1993年 | 40篇 |
1992年 | 24篇 |
1991年 | 44篇 |
1990年 | 28篇 |
1989年 | 27篇 |
1988年 | 33篇 |
1987年 | 32篇 |
1986年 | 32篇 |
1985年 | 39篇 |
1984年 | 26篇 |
1983年 | 23篇 |
1982年 | 21篇 |
1981年 | 34篇 |
1980年 | 27篇 |
1979年 | 24篇 |
1978年 | 17篇 |
1977年 | 26篇 |
1976年 | 27篇 |
1975年 | 15篇 |
1974年 | 24篇 |
1973年 | 25篇 |
1968年 | 11篇 |
排序方式: 共有2573条查询结果,搜索用时 203 毫秒
1.
Bill Robert Fleck Martin Troya Javier Mayerhofer Tanja Wimmer Manuel 《Software and Systems Modeling》2019,18(2):1017-1046
Software and Systems Modeling - Many model transformation scenarios require flexible execution strategies as they should produce models with the highest possible quality. At the same time,... 相似文献
2.
Joshua C. Price Simon J. Levett Valentin Radu David A. Simpson Aina Mogas Barcons Christopher F. Adams Melissa L. Mather 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(22)
Fluorescent nanodiamonds (fNDs) containing nitrogen vacancy (NV) centers are promising candidates for quantum sensing in biological environments. This work describes the fabrication and implementation of electrospun poly lactic‐co‐glycolic acid (PLGA) nanofibers embedded with fNDs for optical quantum sensing in an environment, which recapitulates the nanoscale architecture and topography of the cell niche. A protocol that produces uniformly dispersed fNDs within electrospun nanofibers is demonstrated and the resulting fibers are characterized using fluorescent microscopy and scanning electron microscopy (SEM). Optically detected magnetic resonance (ODMR) and longitudinal spin relaxometry results for fNDs and embedded fNDs are compared. A new approach for fast detection of time varying magnetic fields external to the fND embedded nanofibers is demonstrated. ODMR spectra are successfully acquired from a culture of live differentiated neural stem cells functioning as a connected neural network grown on fND embedded nanofibers. This work advances the current state of the art in quantum sensing by providing a versatile sensing platform that can be tailored to produce physiological‐like cell niches to replicate biologically relevant growth environments and fast measurement protocols for the detection of co‐ordinated endogenous signals from clinically relevant populations of electrically active neuronal circuits. 相似文献
3.
Wyatt L. Brown Douglas A. Day Harald Stark Demetrios Pagonis Jordan E. Krechmer Xiaoxi Liu Derek J. Price Erin F. Katz Peter F. DeCarlo Catherine G. Masoud Dongyu S. Wang Lea Hildebrandt Ruiz Caleb Arata David M. Lunderberg Allen H. Goldstein Delphine K. Farmer Marina E. Vance Jose L. Jimenez 《Indoor air》2021,31(1):141-155
Understanding the sources and composition of organic aerosol (OA) in indoor environments requires rapid measurements, since many emissions and processes have short timescales. However, real-time molecular-level OA measurements have not been reported indoors. Here, we present quantitative measurements, at a time resolution of five seconds, of molecular ions corresponding to diverse aerosol-phase species, by applying extractive electrospray ionization mass spectrometry (EESI-MS) to indoor air analysis for the first time, as part of the highly instrumented HOMEChem field study. We demonstrate how the complex spectra of EESI-MS are screened in order to extract chemical information and investigate the possibility of interference from gas-phase semivolatile species. During experiments that simulated the Thanksgiving US holiday meal preparation, EESI-MS quantified multiple species, including fatty acids, carbohydrates, siloxanes, and phthalates. Intercomparisons with Aerosol Mass Spectrometer (AMS) and Scanning Mobility Particle Sizer suggest that EESI-MS quantified a large fraction of OA. Comparisons with FIGAERO-CIMS shows similar signal levels and good correlation, with a range of 100 for the relative sensitivities. Comparisons with SV-TAG for phthalates and with SV-TAG and AMS for total siloxanes also show strong correlation. EESI-MS observations can be used with gas-phase measurements to identify co-emitted gas- and aerosol-phase species, and this is demonstrated using complementary gas-phase PTR-MS observations. 相似文献
4.
Removal of gold from basic solutions containing [Au(CN)2]? has been demonstrated using the inherently conducting polymer polypyrrole. Polymers containing sulfonated aromatic dopants have been found to display a significant ability to remove gold from such solutions. Experiments performed in solutions containing both gold and copper cyanide complexes indicate that the recovery process is not highly selective. However, the polypyrroles used display significantly faster rates of gold recovery than activated carbon. © 2003 Society of Chemical Industry 相似文献
5.
A case of traumatic extracranial vertebral arterial dissection leading to vertebrobasilar thrombosis and respiratory compromise requiring mechanical ventilation was managed with intraarterial thrombolysis and stenting of the vertebral intimal dissection. In contrast to similar, previously reported cases, this critically ill patient made a full recovery, returning to his job as a secondary school teacher. 相似文献
6.
We consider a language of operations which pass parameters by means of a stack. An algebra over the set of type signatures is introduced, which allows the type signature of a program to be obtained from the type signatures of its constituent operations.Although the theories apply in principle to any stack based language, they have been evolved with particular regard to the proposed ANSI Standard Forth language, which is currently implemented in a type free manner. We hope this work will stimulate an interest in Forth amongst those applying algebraic techniques in software engineering, and we hope to lay the theoretical foundations for implementing practical type checkers to support Forth. 相似文献
7.
D Averill D Blockus B Brabson J Brom C Jung H Ogren DR Rust M Derrick P Kooijman JS Loos B Musgrave LE Price J Repond K Sugano B Cork C Akerlof J Chapman D Errede MT Ken DI Meyer H Neal D Nitz R Thun R Tschirhart S Abachi P Baringer BG Bylsma R DeBonte D Koltick EH Low RL McIlwain DH Miller CR Ng EI Shibata 《Canadian Metallurgical Quarterly》1989,39(1):123-137
8.
D.H.R. Price J.A. Sharp 《International Journal of Electrical Power & Energy Systems》1985,7(3):131-137
Peak demand forecasts obtained from six different univariate forecasting methods, under a range of conditions, were used to drive a capacity acquisition model of a large electrical supply system; and the resulting physical and financial performance of the model was observed for each set of forecasts. The results obtained are discussed in the context of their implications for the choice of load forecasting method used in capacity acquisition planning by a power supply undertaking. 相似文献
9.
Bill Woodruff 《电子设计技术》2005,12(1):136-136,138-139
较低的速度通常不能算是创新,但在10 Gbps以太网的领域内,两种“低速”互连标准,即LX4和CX4,正在降低实现成本,并实现新的应用。 相似文献
10.