全文获取类型
收费全文 | 5714篇 |
免费 | 357篇 |
国内免费 | 45篇 |
专业分类
电工技术 | 74篇 |
综合类 | 20篇 |
化学工业 | 1594篇 |
金属工艺 | 124篇 |
机械仪表 | 220篇 |
建筑科学 | 154篇 |
矿业工程 | 4篇 |
能源动力 | 375篇 |
轻工业 | 559篇 |
水利工程 | 82篇 |
石油天然气 | 36篇 |
无线电 | 548篇 |
一般工业技术 | 1061篇 |
冶金工业 | 276篇 |
原子能技术 | 83篇 |
自动化技术 | 906篇 |
出版年
2024年 | 18篇 |
2023年 | 105篇 |
2022年 | 290篇 |
2021年 | 398篇 |
2020年 | 299篇 |
2019年 | 327篇 |
2018年 | 359篇 |
2017年 | 296篇 |
2016年 | 324篇 |
2015年 | 194篇 |
2014年 | 323篇 |
2013年 | 532篇 |
2012年 | 306篇 |
2011年 | 312篇 |
2010年 | 277篇 |
2009年 | 244篇 |
2008年 | 166篇 |
2007年 | 145篇 |
2006年 | 132篇 |
2005年 | 95篇 |
2004年 | 74篇 |
2003年 | 71篇 |
2002年 | 55篇 |
2001年 | 42篇 |
2000年 | 36篇 |
1999年 | 37篇 |
1998年 | 69篇 |
1997年 | 59篇 |
1996年 | 42篇 |
1995年 | 53篇 |
1994年 | 24篇 |
1993年 | 34篇 |
1992年 | 30篇 |
1991年 | 25篇 |
1990年 | 24篇 |
1989年 | 22篇 |
1988年 | 15篇 |
1987年 | 30篇 |
1986年 | 30篇 |
1985年 | 22篇 |
1984年 | 30篇 |
1983年 | 26篇 |
1982年 | 16篇 |
1981年 | 8篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1975年 | 8篇 |
排序方式: 共有6116条查询结果,搜索用时 62 毫秒
51.
The characteristics of ion beams of hydrogen and nitrogen with different filling pressures emitted from the plasma focus device of 2.3 kJ energy are investigated. CR-39 SSNTDs are employed for the registration of tracks of ions. The exposed detectors are etched in 6N NaOH solution at 70°C and then examined with an optical microscope. The ion flux is estimated to be of the order of 105–6 tracks/cm2. The flux with the radial position does not exhibit any regular pattern of variation. 相似文献
52.
Engineering with Computers - A novel Harris hawks optimization algorithm is applied to microchannel heat sinks for the minimization of entropy generation. In the formulation of the heat transfer... 相似文献
53.
Izzuddin Tarmizi Ahmad Safri Norlaili Mat Othman Mohd Afzan 《Neural computing & applications》2021,33(11):6233-6246
Neural Computing and Applications - This paper introduces the use of the one-dimensional convolutional neural network (1D-CNN) for end-to-end EEG decoding with application towards a BCI system with... 相似文献
54.
Khan Muhammad Hussain Saleem Zainab Ahmad Muhammad Sohaib Ahmed Ayaz Hamail Mazzara Manuel Raza Rana Aamir 《Neural computing & applications》2021,33(21):14507-14521
Neural Computing and Applications - Preserving red-chili quality is of utmost importance in which the authorities demand quality techniques to detect, classify, and prevent it from impurities. For... 相似文献
55.
Zaki Ahmad M. El-Nagar Ahmad M. El-Bardini Mohammad Soliman F. A. S. 《Neural computing & applications》2021,33(5):1515-1531
Neural Computing and Applications - For the current paper, the technique of feed-forward neural network deep learning controller (FFNNDLC) for the nonlinear systems is proposed. The FFNNDLC... 相似文献
56.
Meraj Talha Rauf Hafiz Tayyab Zahoor Saliha Hassan Arslan Lali M. IkramUllah Ali Liaqat Bukhari Syed Ahmad Chan Shoaib Umar 《Neural computing & applications》2021,33(17):10737-10750
Neural Computing and Applications - Lung cancer is a deadly disease if not diagnosed in its early stages. However, early detection of lung cancer is a challenging task due to the shape and size of... 相似文献
57.
Elkenawy Ahmed El-Nagar Ahmad M. El-Bardini Mohammad El-Rabaie Nabila M. 《Neural computing & applications》2021,33(15):9221-9240
Neural Computing and Applications - This study introduces a neural network (NN) adaptive tracking controller-based reinforcement learning (RL) scheme for unknown nonlinear systems. First, an... 相似文献
58.
The paper proposes a new approach to find semantic meanings in visual object class structure, in line with the Gestalt laws
of proximity. Micro level semantic structures are formed by line segments (arcs also approximated into line segments based
on pixel deviation threshold) which are in close proximity. These structures are hierarchically combined till a semantic label
can be assigned. The algorithm extracts semantic groups, their inter-relations and represents these using a graph. Invariant
geometrical properties of the groups and relations are used as vertex and edge labels. A graph model captures the inter class
variability by analyzing the repetitiveness of structures and relations and uses it as a weighting factor for classification.
The algorithm has been tested on a standard benchmark database and compared with existing approaches. 相似文献
59.
Autonomous mapping of HL7 RIM and relational database schema 总被引:1,自引:0,他引:1
Shagufta Umer Muhammad Afzal Maqbool Hussain Khalid Latif Hafiz Farooq Ahmad 《Information Systems Frontiers》2012,14(1):5-18
Healthcare systems need to share information within and across the boundaries in order to provide better care to the patients.
For this purpose, they take advantage of the full potential of current state of the art in healthcare standards providing
interoperable solutions. HL7 V3 specification is an international message exchange and interoperability standard. HL7 V3 messages
exchanged between healthcare applications are ultimately recorded into local healthcare databases, mostly in relational databases.
In order to bring these relational databases in compliance with HL7, mappings between HL7 RIM (Reference Information Model)
and relational database schema are required. Currently, RIM and database mapping is largely performed manually, therefore
it is tedious, time consuming, error prone and expensive process. It is a challenging task to determine all correspondences
between RIM and schema automatically because of extreme heterogeneity issues in healthcare databases. To reduce the amount
of manual efforts as much as possible, autonomous mapping approaches are required. This paper proposes a technique that addresses
the aforementioned mapping issue and aligns healthcare databases to HL7 V3 RIM specifications. Furthermore, the proposed technique
has been implemented as a working application and tested on real world healthcare systems. The application loads the target
healthcare schema and then identifies the most appropriate match for tables and the associated fields in the schema by using
domain knowledge and the matching rules defined in the Mapping Knowledge Repository. These rules are designed to handle the
complexity of semantics found in healthcare databases. The GUI allows users to view and edit/re-map the correspondences. Once
all the mappings are defined, the application generates Mapping Specification, which contains all the mapping information
i.e. database tables and fields with associated RIM classes and attributes. In order to enable the transactions, the application
is facilitated with the autonomous code generation from the Mapping Specification. The Code Generator component focuses primarily
on generating custom classes and hibernate mapping files against the runtime system to retrieve and parse the data from the
data source—thus allows bi-directional HL7 to database communication, with minimum programming required. Our experimental
results show 35–65% accuracy on real laboratory systems, thus demonstrating the promise of the approach. The proposed scheme
is an effective step in bringing the clinical databases in compliance with RIM, providing ease and flexibility. 相似文献
60.
Mohd Akram Hira Lal Mohammad Osama Farah Ansari Sana Anwar Kabir-ud-Din Ajaz Ahmad Samreen Naved Azum Hadi M. Marwani Abdullah M. Asiri 《Journal of surfactants and detergents》2021,24(1):35-49
In this study, we prepared a novel series of diester-functionalized cationic gemini surfactants (Cm-E2O2-Cm) containing ethylene oxide as a spacer with varying alkyl chain lengths and characterized by 1H NMR, FT-IR, elemental analysis, and ESI-MS. The physicochemical properties of the geminis were explored by tensiometry, fluorescence, dye solubilization, and Krafft point. These geminis acquire superior surface activity than the conventional surfactants. Fluorescence spectroscopy analysis affirmed that the micropolarity and aggregation number of micelles diminished with increase in the alkyl chain length. These geminis represent a new group of amphiphiles of considerably high biodegradability, better cleavability, and low toxicity as assessed by BOD test, FT-IR analysis, and HC50 analysis, respectively. They also showed significant level of antimicrobial activity toward some specified bacterial strains of Gram-positive and Gram-negative by using agar well diffusion method. Furthermore, the thermogravimetric analysis provided information regarding thermal stabilities of the newly synthesized gemini surfactants. 相似文献