全文获取类型
收费全文 | 579篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 24篇 |
化学工业 | 107篇 |
金属工艺 | 4篇 |
机械仪表 | 12篇 |
建筑科学 | 10篇 |
能源动力 | 12篇 |
轻工业 | 34篇 |
无线电 | 91篇 |
一般工业技术 | 129篇 |
冶金工业 | 121篇 |
原子能技术 | 19篇 |
自动化技术 | 36篇 |
出版年
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 19篇 |
2012年 | 10篇 |
2011年 | 21篇 |
2010年 | 17篇 |
2009年 | 11篇 |
2008年 | 17篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 28篇 |
2002年 | 10篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 46篇 |
1997年 | 32篇 |
1996年 | 24篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 13篇 |
1990年 | 20篇 |
1989年 | 14篇 |
1988年 | 16篇 |
1987年 | 15篇 |
1986年 | 16篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 7篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有599条查询结果,搜索用时 154 毫秒
591.
We presented an automatic method for detecting and tracking colloidal gold fiducial markers for alignment in electron tomography (ET). The second-order derivative of direction was used to detect a fiducial marker accurately. The detection was optimized to be selective to the size of fiducial markers. A preliminary tracking result from the normalized correlation coefficient was refined using the detector. A constraint model considering the relationship among the fiducial markers on different images was developed for removing outlier. The three-dimensional positions of the detected fiducial markers and the projection parameters of tilt images were calculated for post process. The accuracy of detection and tracking results was evaluated from the residues by the software IMOD. Application on transmission electron microscopic images also indicated that the presented method could provide a useful approach to automatic alignment in ET. 相似文献
592.
The kinetics of intercalation are discussed using a pulsed laser deposition (PLD) film electrode and electrochemical impedance analysis. Films of LiNi0.8Co0.2O2, deposited on single crystal substrates, were used for the study. The films have intercalative or blocking orientations on different crystal surfaces of the substrates. Impedance spectra show that there are at least three elemental processes in intercalation. Two processes at higher frequencies suggest that they occur at the electrode surface and are influenced by the orientation of the film. The third process appearing at low frequencies below 1 Hz indicates lithium motion in the bulk structure and shows the largest resistance among the three processes. This lithium conduction in a thin PLD film shows a semicircular response and is considered to be influenced more by the structure due to the nanometer-scale thickness. 相似文献
593.
Ken Kokubo Shizuka Yamakura Yuji Nakamura Hiroshi Ueno Takumi Oshima 《Fullerenes, Nanotubes and Carbon Nanostructures》2014,22(1-3):250-261
We have recently developed a facile synthetic method for highly water-soluble fullerene, so-called fullerenol, for the treatment of fullerene with hydrogen peroxide. This method was applied to fullerene soot to yield the corresponding new hydrophilic carbon materials, and the obtained products were subjected to infrared spectroscopy and elemental analysis. The DLS particle size analysis demonstrated the relatively high dispersion of hydrophilic fullerene soot with a diameter of ?70 nm in water, while the hydrophilic activated carbon obtained by the same treatment showed the larger aggregation with diameters of 200 and 970 nm. The surface analysis using FE-SEM showed the difference in morphology between fullerene soot and activated carbon as well as between before and after hydrophilic treatment of the soot with hydrogen peroxide. Moreover, this hydrophilic fullerene soot exhibited high antioxidant activity (%AOA) up to 87% compared with fullerenol C60(OH)36 (54%) and C60 (50%) evaluated by β-carotene bleaching method. 相似文献
594.
Removal of excess fluoride from groundwater using natural coagulant Moringa oleifera Lam and microfiltration 下载免费PDF全文
595.
Nishi T. Shinozaki R. Konishi M. 《Automation Science and Engineering, IEEE Transactions on》2008,5(2):259-274
Planning coordination for multiple companies has received much attention from viewpoints of global supply chain management. In practical situations, a plausible plan for multiple companies should be created by mutual negotiation and coordination without sharing such confidential information as inventory costs, setup costs, and due date penalties for each company. In this paper, we propose a framework for distributed optimization of supply chain planning using an augmented Lagrangian decomposition and coordination approach. A feature of the proposed method is that it can derive a near-optimal solution without requiring all of the information. The proposed method is applied to supply chain planning problems for a petroleum complex, and a midterm planning problem for multiple companies. Computational experiments demonstrate that the average gap between a solution derived by the proposed method and the optimal solution is within 3% of the performance index, even though only local information is used to derive a solution for each company. 相似文献
596.
This paper presents an interactive system for realistic visualization of earth-scale clouds. Realistic images can be generated at interactive frame rates while the viewpoint and the sunlight directions can be changed interactively. The realistic display of earth-scale clouds requires us to render large volume data representing the density distribution of the clouds. However, this is generally time-consuming and it is difficult to achieve the interactive performance, especially when the sunlight direction ca... 相似文献
597.
K Ohta M Nishi M Ueda S Ohyama T Matsubara T Takahashi T Nakajima 《Canadian Metallurgical Quarterly》1998,99(9):589-594
Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients. 相似文献
598.
The facilitated transfer of alkali metal cations (Li+, Na+, K+, Rb+, Cs+) by dibenzo-18-crown-6 (DB18C6) across the electrochemically polarizable interface between an aqueous solution (W) and a hydrophobic ionic liquid, N-octadecylisoquinolinium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate ([C18Iq][TFPB]), has been studied using cyclic voltammetry at the interface formed at the tip of a micropipet. In cyclic voltammograms (CVs), the current due to the facilitated transfer of the cations by DB18C6 from W to [C18Iq][TFPB] can be measured within the polarized potential window of the [C(18)Iq][TFPB]|W interface. The stoichiometry of the complexes in [C18Iq][TFPB] for Li+, Na+, K+, and Rb+ are found to be 1:1 while for the Cs+ transfer both 1:1 and 1:2 complexes are likely to be formed. The formation constants of the 1:1 complexes for Li+, Na+, K+, and Rb+ in [C18Iq][TFPB], , evaluated from CVs are log = 5.0, 7.0, 8.2, and 7.3, respectively. The value for K+ is 1 order of magnitude greater than that for Na+. This higher selectivity of DB18C6 to K+ over Na+ in [C18Iq][TFPB] compared with that in molecular solvents suggests that the RTIL provides a unique solvation environment for the complexations of DB18C6 with the ions. 相似文献
599.
Rajitha Tennekoon Janaka Wijekoon Erwin Harahap Hiroaki Nishi 《IEEJ Transactions on Electrical and Electronic Engineering》2016,11(Z1):S122-S133
Internet communication message protocol (ICMP)‐based traceability methods are widely used to trace packets over the Internet; however, in their attacks, adversaries likewise use ICMP packets. Furthermore, the lack of security in ICMP‐based traceability results in failures for many current traceability methods. Moreover, current routers are unable to provide extended services to Internet users and applications. To address this need, our laboratory has introduced the service‐oriented router (SoR). SoR is middleware that can be implemented on a Cisco AXP and Juniper JunosV App Engine. In this paper, we propose a secure method of providing packet traceability over public networks using SoR features. We implemented a secure packet traceability service prototype on the ns‐3 simulator. The test results conclude that there is a maximum additional cost of 48.69 and 123.91 μs of processing overhead per packet in each hop when the proposed secured traceability service is used with a 128‐bit key space in AES‐GCM and AES‐CTR modes, respectively. Moreover, for 256‐bit key spaces, AES‐GCM and AES‐CTR modes consumed additional 47.18 and 123.25 μs, respectively, over the plain traceability. Yet, from the evaluations on the test bed topology, it clearly shown that the proposed method was 79% faster than the conventional trace route method in providing the secured end‐to‐end traceability. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献