全文获取类型
收费全文 | 3797篇 |
免费 | 337篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 66篇 |
综合类 | 2篇 |
化学工业 | 1008篇 |
金属工艺 | 129篇 |
机械仪表 | 100篇 |
建筑科学 | 102篇 |
矿业工程 | 28篇 |
能源动力 | 128篇 |
轻工业 | 491篇 |
水利工程 | 22篇 |
石油天然气 | 16篇 |
无线电 | 224篇 |
一般工业技术 | 929篇 |
冶金工业 | 156篇 |
原子能技术 | 42篇 |
自动化技术 | 695篇 |
出版年
2023年 | 56篇 |
2022年 | 47篇 |
2021年 | 135篇 |
2020年 | 121篇 |
2019年 | 118篇 |
2018年 | 224篇 |
2017年 | 211篇 |
2016年 | 235篇 |
2015年 | 163篇 |
2014年 | 206篇 |
2013年 | 417篇 |
2012年 | 239篇 |
2011年 | 246篇 |
2010年 | 217篇 |
2009年 | 187篇 |
2008年 | 132篇 |
2007年 | 88篇 |
2006年 | 63篇 |
2005年 | 31篇 |
2004年 | 42篇 |
2003年 | 46篇 |
2002年 | 38篇 |
2001年 | 45篇 |
2000年 | 36篇 |
1999年 | 30篇 |
1998年 | 45篇 |
1997年 | 33篇 |
1996年 | 41篇 |
1995年 | 32篇 |
1994年 | 37篇 |
1993年 | 31篇 |
1992年 | 26篇 |
1991年 | 25篇 |
1990年 | 26篇 |
1989年 | 24篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 37篇 |
1984年 | 36篇 |
1983年 | 25篇 |
1982年 | 28篇 |
1981年 | 23篇 |
1980年 | 21篇 |
1979年 | 19篇 |
1978年 | 18篇 |
1977年 | 22篇 |
1976年 | 23篇 |
1975年 | 20篇 |
1974年 | 19篇 |
1973年 | 20篇 |
排序方式: 共有4138条查询结果,搜索用时 15 毫秒
121.
B. C. Pak B. S. Cho B. J. Baek C. S. Kim B. G. Min 《Journal of Mechanical Science and Technology》1993,7(3):223-230
Hydrodynamic comparison of two polymer valves with two mechanical valves is presented. The valves were perfused in a steady
flow system, and comparisons between the valves were made on the transvalvular pressure distribution and drop, opening area,
and leakage volume. Particular emphasis was placed on a slit-type bileaflet polymer valve which was newly designed and fabricated
in our research group. The results showed that the functional characteristics of a slit-type bileaflet polymer valve compared
favorably with that of mechanical valves. This valve may be a viable and inexpensive alternative, especially for short-term
use in TAH or VAD systems. 相似文献
122.
Pedersoli E Capotondi F Cocco D Zangrando M Kaulich B Menk RH Locatelli A Mentes TO Spezzani C Sandrin G Bacescu DM Kiskinova M Bajt S Barthelmess M Barty A Schulz J Gumprecht L Chapman HN Nelson AJ Frank M Pivovaroff MJ Woods BW Bogan MJ Hajdu J 《The Review of scientific instruments》2011,82(4):043711
We present a compact modular apparatus with a flexible design that will be operated at the DiProI beamline of the Fermi@Elettra free electron laser (FEL) for performing static and time-resolved coherent diffraction imaging experiments, taking advantage of the full coherence and variable polarization of the short seeded FEL pulses. The apparatus has been assembled and the potential of the experimental setup is demonstrated by commissioning tests with coherent synchrotron radiation. This multipurpose experimental station will be open to general users after installation at the Fermi@Elettra free electron laser in 2011. 相似文献
123.
Linas Minkevičius Vincas Tamošiūnas Martynas Kojelis Ernestas Žąsinas Virginijus Bukauskas Arūnas Šetkus Renata Butkutė Irmantas Kašalynas Gintaras Valušis 《Journal of Infrared, Millimeter and Terahertz Waves》2017,38(6):689-707
A detailed electrical characterization of high-performance bow-tie InGaAs-based terahertz detectors is presented along with simulation results. The local surface potential and tunnelling current were scanned over the surfaces of the detectors by means of Kelvin probe force microscopy (KPFM) and scanning tunnelling microscopy (STM), which also enabled the determination of the Fermi level. Current-voltage curves were measured and modelled using the Synopsys Sentaurus TCAD package to gain deeper insight into the processes involved in detector operation. In addition, we performed finite-difference time-domain (FDTD) simulations to reveal features related to changes in the electric field due to the metal detector contacts. The investigation revealed that field-effect-induced conductivity modulation is a possible mechanism contributing to the high sensitivity of the studied detectors. 相似文献
124.
Tomáš Brázdil Javier Esparza Stefan Kiefer Antonín Kučera 《Formal Methods in System Design》2013,43(2):124-163
The paper gives a summary of the existing results about algorithmic analysis of probabilistic pushdown automata and their subclasses. 相似文献
125.
Jaroslav Keznikl Tomáš Bureš František Plášil Petr Hnětynka 《Software and Systems Modeling》2014,13(2):843-872
In current software systems, connectors play an important role by encapsulating the communication and coordination logic. Since they share common patterns (elements) depending on characteristics of the connections, the elements can be predefined and reused. A method of connector implementation based on a composition of predefined elements naturally comprises two steps: resolution of the connector architecture, and creation of the actual connector code based on the architecture. However, manual resolution of a connector architecture is very difficult due to the number of factors to be considered. Thus, the challenge is to come up with an automated method, able to address all the important factors. In this paper, we present a method for automated resolution of connector architectures based on constraint solving techniques. We exploit a propositional logic with relational calculus for defining a connector theory, a constraint specification reflecting both the predefined parts and the important resolution factors, and employ a constraint solver to find a suitable connector architecture as a model of the theory. As a proof of the concept, we show how the theory can be captured in the Alloy language and resolved via the Alloy Analyzer. 相似文献
126.
127.
Wai Shin Ho Cheng Seong Khor Haslenda Hashim Sandro Macchietto Jiří Jaromír Klemeš 《Clean Technologies and Environmental Policy》2014,16(5):957-970
This work proposes a novel approach called stand-alone hybrid system power pinch analysis (SAHPPA), which is particularly applicable for the design of off-grid distributed energy generation systems. The enhanced graphical tool employs new ways of utilising the recently introduced demand composite curve and supply composite curve while honouring and adapting fundamental energy systems engineering concepts. The SAHPPA method is capable of optimising the capacity of both the power generators and energy storage for biomass (i.e. non-intermittent) and solar photovoltaic (i.e. intermittent) energy technologies, which is a contribution to the emerging area of power pinch analysis. In addition, the procedure considers all possible efficiency losses in the overall system encompassing the charging–discharging and current inversion processes. 相似文献
128.
129.
130.
The thermophysical properties of thin platinum and nickel wires are investigated within the temperature range from room temperature
up to near to the melting point. We have measured the coefficient of heat exchange with the ambient media, the absorption
efficiency factor within the visible range, and the time constant of the bolometer cooling down. The data obtained are approximated
by analytical expressions. 相似文献