全文获取类型
收费全文 | 1621篇 |
免费 | 41篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 12篇 |
综合类 | 1篇 |
化学工业 | 204篇 |
金属工艺 | 13篇 |
机械仪表 | 24篇 |
建筑科学 | 16篇 |
矿业工程 | 5篇 |
能源动力 | 32篇 |
轻工业 | 52篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 152篇 |
一般工业技术 | 119篇 |
冶金工业 | 893篇 |
原子能技术 | 6篇 |
自动化技术 | 131篇 |
出版年
2023年 | 7篇 |
2022年 | 29篇 |
2021年 | 30篇 |
2020年 | 32篇 |
2019年 | 28篇 |
2018年 | 29篇 |
2017年 | 31篇 |
2016年 | 59篇 |
2015年 | 23篇 |
2014年 | 37篇 |
2013年 | 59篇 |
2012年 | 43篇 |
2011年 | 44篇 |
2010年 | 34篇 |
2009年 | 35篇 |
2008年 | 27篇 |
2007年 | 28篇 |
2006年 | 17篇 |
2005年 | 28篇 |
2004年 | 10篇 |
2003年 | 19篇 |
2002年 | 8篇 |
2001年 | 18篇 |
2000年 | 4篇 |
1999年 | 34篇 |
1998年 | 281篇 |
1997年 | 151篇 |
1996年 | 125篇 |
1995年 | 64篇 |
1994年 | 40篇 |
1993年 | 55篇 |
1992年 | 14篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 17篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 21篇 |
1976年 | 43篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1973年 | 4篇 |
排序方式: 共有1667条查询结果,搜索用时 15 毫秒
161.
162.
Dan Chiappe Robert Conrad Rorie Corey Andrew Morgan Kim-Phuong L. Vu 《Theoretical Issues in Ergonomics Science》2014,15(1):69-87
Theories of team situation awareness (SA) differ in the information they require operators to have for effective coordination. Endsley stresses shared SA, whereas distributed SA argues that coordination involves transactive and compatible SA. We distinguish between weak and strong shared SA, and argue the latter enhances communication and increases team cohesion. Although we agree with Endsley on the importance of shared SA, we argue her account of how it is acquired exceeds the working memory capacity of individual team members. We offer an account consistent with our situated SA perspective that claims individuals off-load information to their environment whenever possible to minimise effortful internal processing. We argue that our approach, in conjunction with Pickering and Garrod's (2004, Towards a mechanistic psychology of dialogue. Behavioral and Brain Sciences, 27, pp. 169–226) interactive-alignment model, can explain how shared SA is acquired, relying on automatic processes enacted when individuals interact in conversations. This approach can be used to study team SA in many complex and distributed systems. 相似文献
163.
Seamless inter-technology mobility is one of the fundamental requirements of next generation mobile networks. For seamless mobility, handover delay and packet loss should be minimized. However, existing solutions suffer from a number of shortcomings in satisfying these requirements: first, handover preparation schemes fail to minimize the handover delay as much as possible. Second, minimizing packet loss which is usually using soft handover (SHO) schemes are excessively wasteful of scarce resources. In this paper, we propose the uninterrupted proactive connection transfer for IMS mobility enhancement (UPTIME) mobility framework which achieves seamless mobility while minimizing excessive power and radio resource consumption. UPTIME incorporates two mechanisms; a proactive handover preparation method and an optimized SHO technique for handover execution. We demonstrate the benefits of the proposed framework through both analysis and simulation. Our simulation results for typical LTE/WiMAX handovers show that the handover preparation delay can be reduced by 70 %, and good packet loss performance can be achieved whilst saving 43 % of radio resources and 48 % of battery power. 相似文献
164.
Kihun An Dokyung Kim Yen Hai Thi Tran Dung Tien Tuan Vu Seong Jun Park Jiyoung Heo Young Joo Lee Seung-Wan Song 《Advanced functional materials》2024,34(8):2311782
Fast charging of Li-ion batteries (LIBs) beyond standard 0.3 C (charged in 3.3 h) are desperately pursued but hindered by sluggish desolvation kinetics of ethylene carbonate-based traditional electrolyte, and Li-plating and dendrites growth at graphite anode and fire hazard. Herein, a new class of weakly binding all linear molecules-based nonflammable electrolyte (WNLE) is reported, comprising 1 m LiPF6 in ethyl methyl carbonate and 2,2,2-trifluoroethyl acetate with additives for 10–20 times faster charging LIBs than traditional ones. The critical benefits of WNLE are 44% lower viscosity, 62% higher Li+ diffusion coefficient, 20% higher Li+ transference number, and 17% lower desolvation energy, which promotes diffusion kinetics and desolvation kinetics of Li+ in the vicinity of graphite anode enabling dendrites-free LIB, along with nonflammability. Under 3 C (charged in 20 min), WNLE-based industrial 800 mAh graphite//LiNi0.8Mn0.1Co0.1O2 (high active mass 13 mg cm−2) Li-ion pouch battery achieves outstanding 700 cycles, delivering 82% capacity retention and high Coulombic efficiencies ≈100%. Robust solid electrolyte interphase layers formed at the anode and cathode mitigate interfacial failures, making fast charge to 7 C and longer cycle-life. This new class of electrolyte formulation is a promising solution and a new opportunity to realize safe and long operation of fast-charging LIBs for practical applications. 相似文献
165.
Xuan-Hai Do My Hanh Thi Hoang Anh-Tuan Vu Lai-Thanh Nguyen Dung Thi Thuy Bui Duy-Thanh Dinh Xuan-Hung Nguyen Uyen Thi Trang Than Hien Thi Mai Thuy Thanh To Tra Ngoc Huong Nguyen Nhung Thi My Hoang 《International journal of molecular sciences》2022,23(20)
Although curcumin in the form of nanoparticles has been demonstrated as a potential anti-tumor compound, the impact of curcumin and nanocurcumin in vitro on normal cells and in vivo in animal models is largely unknown. This study evaluated the toxicity of curcumin-loaded micelles in vitro and in vivo on several tumor cell lines, primary stromal cells, and zebrafish embryos. Breast tumor cell line (MCF7) and stromal cells (human umbilical cord vein endothelial cells, human fibroblasts, and human umbilical cord-derived mesenchymal stem cells) were used in this study. A zebrafish embryotoxicity (FET) assay was conducted following the Organisation for Economic Co-operation and Development (OECD) Test 236. Compared to free curcumin, curcumin PM showed higher cytotoxicity to MCF7 cells in both monolayer culture and multicellular tumor spheroids. The curcumin-loaded micelles efficiently penetrated the MCF7 spheroids and induced apoptosis. The nanocurcumin reduced the viability and disturbed the function of stromal cells by suppressing cell migration and tube formation. The micelles demonstrated toxicity to the development of zebrafish embryos. Curcumin-loaded micelles demonstrated toxicity to both tumor and normal primary stromal cells and zebrafish embryos, indicating that the use of nanocurcumin in cancer treatment should be carefully investigated and controlled. 相似文献
166.
During T cell development, assembly of the mutisubunit T cell receptor (TCR) complex is regulated by the differential stability of newly synthesized TCRalpha molecules, having a half-life of approximately 20 min in immature CD4+CD8+ thymocytes compared with >75 min in mature T cells. The molecular basis for TCRalpha instability in CD4+CD8+ thymocytes is unknown but has been postulated to involve abnormalities in N-glycan processing and calnexin assembly as perturbation of these pathways markedly destabilizes TCRalpha proteins in all other T cell types examined. Here, we compared the processing of TCRalpha glycoproteins and their assembly with calnexin and calreticulin chaperones in CD4+CD8+ thymocytes and splenic T cells. These studies show that TCRalpha glycoproteins synthesized in CD4+CD8+ thymocytes were processed in a similar manner as those made in splenic T cells and that TCRalpha proteins stably associated with calnexin in both cell types. Interestingly, however, TCRalpha association with the calnexin-related molecule calreticulin was decreased in CD4+CD8+ thymocytes compared with splenic T cells. Finally, TCRalpha degradation in CD4+CD8+ thymocytes was impaired by inhibitors of proteasome activity, which was correlated with stabilization of calnexin.TCRalpha complexes. These data demonstrate that calnexin association is not sufficient to protect TCRalpha proteins from rapid degradation in CD4+CD8+ thymocytes, suggesting that additional components of the quality control system of the endoplasmic reticulum operate to ensure the proper folding of nascent TCRalpha glycoproteins. 相似文献
167.
Mobile software agents: an overview 总被引:10,自引:0,他引:10
168.
RE O'Carroll A Moffoot KP Ebmeier C Murray GM Goodwin 《Canadian Metallurgical Quarterly》1993,23(2):341-347
Eighteen patients suffering from Alcoholic Korsakoff's Syndrome participated in a placebo-controlled double-blind cross-over trial of clonidine 0.3 mg b.d. for two weeks versus matched placebo for two weeks. A detailed neuropsychological assessment was carried out at the end of each treatment phase and staff ratings of behaviour were also obtained. Clonidine treatment resulted in no significant improvement over placebo on any of the cognitive measures employed. The results contradict previous smaller studies which had suggested that chronic treatment with clonidine had a memory-enhancing effect in Korsakoff's syndrome. 相似文献
169.
Antoine Picot Sylvie Charbonnier Alice Caplier Ngoc-Son Vu 《Machine Vision and Applications》2012,23(6):1195-1208
A large number of car crashes are caused by drowsiness every year. The analysis of eye blinks provides reliable information about drowsiness. This paper proposes to study the relation between electrooculogram (EOG) and video analysis for blink detection and characterization. An original method to detect and characterize blinks from a video analysis is presented here. The method uses different filters based on the human retina modelling. A illumination robust filter is first used to normalize illumination variations of the video input. Then, Outer and an Inner Plexiform Layer filters are used to extract energy signals from eye area. The eye detection is processed mixing gradient and projection methods which makes it able to detect even closed eyes. The illumination robust filter makes it possible to detect the eyes even in night conditions, without using external lighting. The video analysis extracts two signals from the eye area measuring the quantity of static edges and moving edges. Blinks are then detected and characterized from these two signals. A comparison between the features extracted from the EOG and the same features extracted from the video analysis is then performed on a database of 14 different people. This study shows that some blink features extracted from the video are highly correlated with their EOG equivalent: the duration, the duration at 50%, the frequency, the percentage of eye closure at 80% and the amplitude velocity ratio. The frame rate influence on the accuracy of the different features extracted is also studied and enlightens on the need of a high frame rate camera to detect and characterize accurately blinks from a video analysis. 相似文献
170.
A young female with ulcerative colitis associated with positive direct and indirect Coombs reaction and severe autoimmune hemolytic anemia is reported. Cortisone was beneficial and total colectomy was promptly followed by subsidence of the hematologic defects. Review of the literature suggests that this complication of ulcerative colitis is uncommon. It basis is unclear. It seems to be expressed through the presence of a "warm" auto-antibody. Colectomy should be strongly considered when severe hemolysis is present but not when the Coombs test is positive alone without significant hemolysis. 相似文献