全文获取类型
收费全文 | 5747篇 |
免费 | 68篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 48篇 |
综合类 | 6篇 |
化学工业 | 809篇 |
金属工艺 | 95篇 |
机械仪表 | 57篇 |
建筑科学 | 277篇 |
矿业工程 | 55篇 |
能源动力 | 122篇 |
轻工业 | 410篇 |
水利工程 | 61篇 |
石油天然气 | 27篇 |
武器工业 | 1篇 |
无线电 | 286篇 |
一般工业技术 | 652篇 |
冶金工业 | 2385篇 |
原子能技术 | 35篇 |
自动化技术 | 497篇 |
出版年
2022年 | 30篇 |
2021年 | 50篇 |
2020年 | 35篇 |
2019年 | 45篇 |
2018年 | 53篇 |
2017年 | 40篇 |
2016年 | 51篇 |
2015年 | 26篇 |
2014年 | 71篇 |
2013年 | 277篇 |
2012年 | 140篇 |
2011年 | 224篇 |
2010年 | 182篇 |
2009年 | 146篇 |
2008年 | 218篇 |
2007年 | 196篇 |
2006年 | 209篇 |
2005年 | 212篇 |
2004年 | 170篇 |
2003年 | 142篇 |
2002年 | 108篇 |
2001年 | 83篇 |
2000年 | 90篇 |
1999年 | 143篇 |
1998年 | 518篇 |
1997年 | 299篇 |
1996年 | 240篇 |
1995年 | 151篇 |
1994年 | 156篇 |
1993年 | 146篇 |
1992年 | 74篇 |
1991年 | 67篇 |
1990年 | 86篇 |
1989年 | 90篇 |
1988年 | 67篇 |
1987年 | 64篇 |
1986年 | 60篇 |
1985年 | 63篇 |
1984年 | 82篇 |
1983年 | 51篇 |
1982年 | 77篇 |
1981年 | 72篇 |
1980年 | 57篇 |
1979年 | 44篇 |
1978年 | 39篇 |
1977年 | 63篇 |
1976年 | 99篇 |
1975年 | 38篇 |
1974年 | 29篇 |
1973年 | 27篇 |
排序方式: 共有5823条查询结果,搜索用时 0 毫秒
91.
92.
Bruce Montag 《电子设计应用》2006,(4):20-21,24
随着显示技术逐渐转移到高性能的平板以及微电子技术,业界需要一种可扩充、开放产业标准的数字接口,以及可以把功能升级的解决方案。这种可升级的显示接口,应能满足企业以及一般消费者的各种需求。DisplayPort就是这种下一代的显示接口,可以为PC、监视器、显示面板、投影仪、以 相似文献
93.
Patricia R. Pfeiffer Angela R. Bielefeldt Tissa Illangasekare Bruce Henry 《Canadian Metallurgical Quarterly》2005,131(10):1447-1452
Laboratory experiments were conducted to investigate the abiotic interactions of soybean oil (SoyOil) and chlorinated ethene (CE) nonaqueous phase liquids (NAPLs). The mixed NAPL density and interfacial tension behaved ideally, as predicted by the volume ratio. The mixed NAPL viscosity increased exponentially from that of the pure CE to that of pure SoyOil as the volume fraction increased. The measured contact angle was highly variable and was unpredictable as a function of the volume composition of the mixed NAPL. The physical property effects indicate that the mobilization of residual CE NAPLs because of SoyOil injection is unlikely. Equilibrium dissolution of CEs from the NAPL mixtures behaved linearly as a function of the mole fraction. Dissolved SoyOil in simulated groundwater enhanced the dissolution of trichloroethene (TCE) during flow tests, increasing the effluent TCE concentration from 141?to?202?mg/L. The ready intermingling of the CE dense nonaqueous phase liquids (DNAPLs) and SoyOil indicate that such interactions may be significant at sites where vegetable oil is injected into DNAPL source areas to enhance in situ anaerobic bioremediation. 相似文献
94.
Sachs-Ericsson Natalie; Blazer Dan; Plant E. Ashby; Arnow Bruce 《Canadian Metallurgical Quarterly》2005,24(1):32
In a population sample (N = 5,877; ages 15 to 54), the authors found childhood sexual and physical abuse to be associated with the 1-year prevalence of serious health problems for both men and women. The authors also found that participants' psychiatric disorders partially mediated the effects of physical and sexual abuse on adult health. However, childhood abuse continued to independently influence health status after the authors controlled for psychiatric disorders. Contrary to expectations, individuals who experienced a combination of sexual and physical abuse did not have a higher frequency of health problems than those who experienced either type of abuse alone. Implications for these findings are discussed, including possible mechanisms that may account for the association between childhood abuse and adult health problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
David J. Fair Rakesh Venkatesh Bruce Boghosian Douglas M. Matson 《Microgravity science and technology》2005,16(1-4):55-58
Certain commercial steel alloys exhibit a two-step phase transformation process during solidification when substantial undercooling of the liquid allows access to the metastable phase. This two-step transformation leads to a desirable microstructure under certain conditions. Electrostatic Levitation (ESL) and Electromagnetic Levitation (EML) are two methods of containerless processing used to study how nucleation and growth kinetics influence the transformation delay between phases. Because the two facilities show substantially different delay results, the test environment differences have been analyzed to determine the root cause of this deviation. In particular, the difference in sample size between ESL and EML is examined and modeling shows that this difference is not the controlling factor in determining transformation delay behavior. 相似文献
96.
The goal of this research was to operationalize the information technology infrastructure (ITI) concept by identifying its underlying dimensions and establishing a valid and reliable measure for the construct. In order to accomplish this task with the highest degree of certainty, two approaches were sequentially applied: exploratory factor analysis and confirmatory factor analysis. In evaluating the confirmatory factor model, a step-by-step process was employed, assessing unidimensionality, reliability, discriminant validity, and nomological validity. The dimensions of ITI were determined to be: Chief Information Officer, IT Planning, IT Security, Technology Integration, Advisory Committee, Enterprise Model, and Data Administration. Researchers may now make use of this validated ITI measure to conduct investigations of ITI and other organizational measures. Implications of the ITI measure with other organizational initiatives such as electronic commerce and knowledge management are explored. 相似文献
97.
Gaurang Pant Prakaipetch Punchaipetch M. J. Kim Robert M. Wallace Bruce E. Gnade 《Thin solid films》2004,460(1-2):242-246
Physical and electrical properties of hafnium silicon oxynitride (HfSixOyNz) dielectric films prepared by UV ozone oxidation of hafnium silicon nitride (HfSiN) followed by annealing to 450 °C are reported. Interfacial layer growth was minimized through room temperature deposition and subsequent ultraviolet/ozone oxidation. The capacitance–voltage (C–V) and current–voltage (I–V) characteristics of the as-deposited and annealed HfSixOyNz are presented. These 4 nm thick films have a dielectric constant of 8–9 with 12 at.% Hf composition, with a leakage current density of 3×10−5 A/cm2 at Vfb+1 V. The films have a breakdown field strength >10 MV/cm. 相似文献
98.
Raj V. Siddharthan Vela Ganeshwara Bruce L. Kutter Magdy El-Desouky Robert V. Whitman 《Canadian Metallurgical Quarterly》2004,130(1):26-35
A relatively simple rigid plastic multiblock computational model has been developed to predict the permanent seismic displacement of mechanically stabilized earth (MSE) walls. The model formulation was based on many observations made from a series of centrifuge tests carried out on many different configurations of MSE walls. The proposed model is similar to the sliding block method of Newmark. The approach accounted for the variation in acceleration within the backfill and the nonuniform nature of the permanent wall face deformation. The predictive capability of the proposed model has been verified using centrifuge test results obtained for four MSE walls each subjected to three earthquake excitations with strength varying between 0.48 and 0.9g. The analytical model captures many aspects of the characteristic deformation behavior of MSE walls observed in the centrifuge tests. In each of the eleven wall displacement cases studied, the backfill friction angle that yielded a good match between the computed and measured maximum wall displacement was consistent with the corresponding laboratory measured values. 相似文献
99.
Evidence-based practice and empirically supported treatment movements are potent forces that affect the practice of psychology today and have the potential to mandate the types of treatments psychologists conduct. The histories of these movements reveal that certain aspects of therapy valued by psychologists have been ignored. It is shown that the evidence-based movements (a) overemphasize treatments and treatment differences and (b) ignore aspects of psychotherapy that have been shown to be related to outcome, such as variation among psychologists, the relationship, and other common factors. It is important that psychologists understand the development of these movements so that they can be critical consumers of research and can effectively influence the future course of events. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Bruce Potter 《Network Security》2004,2004(1):4-5
When speaking about wireless security, I get asked many questions. Some revolve around technical solutions to problems people are facing. For instance, one individual recently asked me my opinion on the ease at which an attacker can break an md5-based EAP method (my answer? If the md5 EAP method is not encapsulated in an encrypted tunnel such as that provided in PEAP, a dedicated attacker could easily spoof an md5-based authentication process). 相似文献