全文获取类型
收费全文 | 1052篇 |
免费 | 48篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 27篇 |
综合类 | 1篇 |
化学工业 | 258篇 |
金属工艺 | 22篇 |
机械仪表 | 25篇 |
建筑科学 | 31篇 |
矿业工程 | 2篇 |
能源动力 | 135篇 |
轻工业 | 63篇 |
水利工程 | 5篇 |
石油天然气 | 9篇 |
无线电 | 124篇 |
一般工业技术 | 195篇 |
冶金工业 | 61篇 |
原子能技术 | 10篇 |
自动化技术 | 137篇 |
出版年
2024年 | 1篇 |
2023年 | 28篇 |
2022年 | 55篇 |
2021年 | 82篇 |
2020年 | 57篇 |
2019年 | 65篇 |
2018年 | 47篇 |
2017年 | 46篇 |
2016年 | 52篇 |
2015年 | 39篇 |
2014年 | 56篇 |
2013年 | 86篇 |
2012年 | 74篇 |
2011年 | 65篇 |
2010年 | 48篇 |
2009年 | 36篇 |
2008年 | 26篇 |
2007年 | 27篇 |
2006年 | 17篇 |
2005年 | 19篇 |
2004年 | 20篇 |
2003年 | 16篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 16篇 |
1999年 | 14篇 |
1998年 | 16篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 11篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有1105条查询结果,搜索用时 15 毫秒
1.
Maqbool Ali Jamil Hussain Sungyoung Lee Byeong Ho Kang Kashif Sattar 《Expert Systems》2020,37(1):e12401
The case-based learning (CBL) approach has gained attention in medical education as an alternative to traditional learning methodology. However, current CBL systems do not facilitate and provide computer-based domain knowledge to medical students for solving real-world clinical cases during CBL practice. To automate CBL, clinical documents are beneficial for constructing domain knowledge. In the literature, most systems and methodologies require a knowledge engineer to construct machine-readable knowledge. Keeping in view these facts, we present a knowledge construction methodology (KCM-CD) to construct domain knowledge ontology (i.e., structured declarative knowledge) from unstructured text in a systematic way using artificial intelligence techniques, with minimum intervention from a knowledge engineer. To utilize the strength of humans and computers, and to realize the KCM-CD methodology, an interactive case-based learning system(iCBLS) was developed. Finally, the developed ontological model was evaluated to evaluate the quality of domain knowledge in terms of coherence measure. The results showed that the overall domain model has positive coherence values, indicating that all words in each branch of the domain ontology are correlated with each other and the quality of the developed model is acceptable. 相似文献
2.
3.
Clean Technologies and Environmental Policy - The concentration of any disinfectant is a major parameter which is used to evaluate the quality of water. Chlorine is the most common disinfecting... 相似文献
4.
The non-uniformity of the air temperatures and the slow flow rate at the plane collector exit constitute the main cause of the limitations of the solar drying systems. In order to obtain an uniform and a variable flow rate for different uses, a hot air generator using concentrated solar radiation is proposed. To improve the thermal efficiency of the generator, a study of the influence of different shape parameters is realized. The generator is simulated in the laboratory while investigating the flow induced by a circular disc heated uniformly by Joule effect at constant temperature. This disc is placed at the entrance of an open ended vertical cylinder of a larger diameter. Thermal radiation emitted by the hot disc heats the cylinder wall. The heating of the fluid at the cylinder-inlet generates a thermosiphon flow around the one created by the hot disc. The comparison of the velocity and the temperature profiles of the resulting flow permits to determine the influence of the cylinder height, the vertical source-cylinder spacing and the radius ratio, on the resulting flow at the system exit. Thus, a judicious choice of the shape parameters entails an improvement of the flow rate as well as the thermal flux absorbed by the air and a good homogenization of the air temperature at the generator exit. 相似文献
5.
A theoretical model for electrons escaping a quantum well under the influence of an applied electric field is developed. Both the thermionic emission and tunneling components of the currents are calculated, taking into account the proper partitioning between the two currents. The group velocity for a nonuniform electron distribution within the quantum well, which is a function of position and energy, and the continuous energy dependence of the quantum well density of states is considered. A comparison between this model and previously reported experimental results are made which demonstrates excellent agreement 相似文献
6.
H.U. Khan K.M. Agrawal M. Anwar S.P. Nautiyal B.S. Rawat 《Petroleum Science and Technology》1998,16(1):145-166
Lubricating oil base stocks differ greatly in their chemical composition and consequently in their physical properties and applications. Influence of waxes and various hydrocarbon type constituents viz saturates and aromatic components on the viscosity and shear stress as a function of temperature in different lube oil base stocks has been studied in the present paper. 相似文献
7.
Hawkins' isothermal model developed to study noise in bipolar junction transistors (BJTs) is modified to investigate bias-dependent noise in heterojunction bipolar transistors (HBTs) by incorporating thermal effects. It is shown that the inclusion of thermal effects into the high-frequency noise model of HBTs is necessary as the temperature of the device may become very different from the ambient temperature, especially at high bias current. Calculation of the noise figure by including the thermal effect shows that the isothermal calculation may underestimate the noise figure at high bias current. It is observed that noise at low bias is ideality factor n dependent whereas high bias noise is insensitive to the variation of n. Moreover, the common base current gain plays a major role in the calculation of the minimum noise figure. The excellent fit obtained between the theoretical calculation and the measured data are attributed to the inclusion of the bias-dependent junction heating as well as C/sub De/ and C/sub bc/ into the present calculation. 相似文献
8.
An asymmetric line-axis compound parabolic concentrating single basin solar still of concentration 1.15, exit aperture 0.24 metres and length 0.48 metres, 30° inclination and 60° half acceptance angle has been designed fabricated and tested. 相似文献
9.
A switching expression is readily convertible to a reliability expression if (a) all ORed terms are disjoint, and (b) all ANDed sums are statistically independent. The usual approach of system reliability analysis makes a primary use of (a) and a secondary use of (b). An alternative approach reverses the roles of (a) and (b). Symbolic reliability expressions for the source-to-terminal reliability of a generalized Indra network (GIN) with nonidentical components are derived by the two approaches. For this particular case, the second approach leads to a shorter, more elegant derivation and simpler novel results. Typical plots of the GIN reliability functions are presented and their properties are discussed. 相似文献
10.
Aziz Romila Anwar Muhammad Waqas Jamal Muhammad Hasan Bajwa Usama Ijaz 《Neural computing & applications》2021,33(21):14707-14721
Neural Computing and Applications - Detecting and correcting misspelled words in a written text are of great importance in many natural language processing applications. Errors can be broadly... 相似文献