全文获取类型
收费全文 | 1029篇 |
免费 | 36篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 230篇 |
金属工艺 | 19篇 |
机械仪表 | 38篇 |
建筑科学 | 20篇 |
矿业工程 | 1篇 |
能源动力 | 26篇 |
轻工业 | 56篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 110篇 |
一般工业技术 | 198篇 |
冶金工业 | 229篇 |
原子能技术 | 6篇 |
自动化技术 | 115篇 |
出版年
2022年 | 15篇 |
2021年 | 29篇 |
2020年 | 17篇 |
2019年 | 23篇 |
2018年 | 36篇 |
2017年 | 18篇 |
2016年 | 32篇 |
2015年 | 18篇 |
2014年 | 21篇 |
2013年 | 55篇 |
2012年 | 35篇 |
2011年 | 35篇 |
2010年 | 30篇 |
2009年 | 40篇 |
2008年 | 33篇 |
2007年 | 34篇 |
2006年 | 31篇 |
2005年 | 28篇 |
2004年 | 23篇 |
2003年 | 24篇 |
2002年 | 25篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 82篇 |
1997年 | 43篇 |
1996年 | 32篇 |
1995年 | 30篇 |
1994年 | 17篇 |
1993年 | 23篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 14篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1970年 | 6篇 |
排序方式: 共有1067条查询结果,搜索用时 31 毫秒
71.
Simplified method of calculating legendre coefficients for computing optical properties of colorants
The Kubelka-Munk (K-M) theory is widely used for instrumental colour measurement and colorant formulation in modern colour technology. The K-M theory is derived with certain assumptions and hence has several limitations. A more rigorous theory called the many-flux (M-F) technique was recently proposed by Mudgett and Richards to overcome the limitations of the K-M theory. Application of the M-F technique requires lengthy computations and hence is not suitable for industrial organizations for day-to-day work. It has been shown that the limitations of the K-M theory and the complexity of the M-F technique can be significantly reduced if simple equations are developed to calculate Legendre coefficients. Empirical equations to calculate Legendre coefficients (an/ao, n = 1,2) are developed. The validity and utility of these equations have been confirmed by computing K-M scattering coefficients and phase functions, and comparing them with those computed using Mie-theory values. The use of these equations to determine the values of refractive index of colorants is also shown. The work reported in this article simplifies to some extent the computation of reflectance using the M-F technique and enable the estimation of K-M scattering coefficients with change in size of pigments. Utility of the proposed equations is established by computing reflectance by the M-F technique and comparing it with values obtained by using rigorous Mie equations for Legendre coefficients. 相似文献
72.
The most important soil characteristies from the viewpoint of the strength of adobe masonry are first studied. Subsequently, based on the acquired knowledge, the effect of some natural additives to the soil is investigated. Simple field tests, devised to identify the most adequate materials for adobe construction and to be easily transmitted to the potential adobe builder are finally proposed. 相似文献
73.
Bengal gram (Cicer aritinum) was infested with Callosobruchis Chinensis (L.) at 20%, 40% and 60% level of infestation and fed to rats for 40 days. Effect of incorporation of uninfested and infested bengal gram on feed intake, weight gain, protein efficiency ratio (PER), true protein digestibility (TPD), biological value (BV), net protein utilization(NPU) and changes in internal organs were studied. Inclusion of infested grains had significant effect on the utilization of proteins. Diets having 60% infested grains had lower PER, TPD, BV and NPU. With increase in level of infestation weight of liver, kidney and spleen decreased significantly. 相似文献
74.
75.
During friction stir welding, polygonal tool pins experience severe stresses and, under certain conditions, loss of functionality due to adhesion of plasticised material on their surfaces. The extent of adhesion is analysed for various pin geometry and welding conditions based on the theory of machining. The effective stresses on the polygonal pins are evaluated following the principles of mechanics. The results show that the polygonal pins with fewer sides can avoid permanent adhesion of plasticised material at higher weld pitch, which is defined as a ratio of welding speed and tool rotational speed. The computed pin geometries for minimum adhesion are compared with the pin profiles recommended by various investigators based on independent experiments. The computed stresses show that pins with larger number of sides will experience lower stresses for any given set of welding variables. 相似文献
76.
Mehta Swati; Orenczuk Steven; Hansen Kevin T.; Aubut Jo-Anne L.; Hitzig Sander L.; Legassic Matthew; Teasell Robert W. 《Canadian Metallurgical Quarterly》2011,56(1):15
Study Design: Systematic review. Objective: To examine the evidence supporting the effectiveness of cognitive behavioral therapy (CBT) for improving psychosocial outcomes in individuals with spinal cord injury (SCI). Method: Electronic databases (MEDLINE, CINAHL, EMBASE, and PsycINFO) were searched for studies published between 1990 and October 2010. Randomized control trials (RCTs) and nonrandomized control trials (non-RCTs) utilizing a CBT intervention to improve psychosocial outcomes (depressive symptomatology, anxiety, coping, and adjustment to disability) in outpatient persons with SCI were included for review. Levels of evidence were assigned to each study using a modified Sackett scale. Effect size calculations for the interventions were provided where possible. Results: Nine studies met the inclusion criteria. The studies reviewed included two RCTs, six prospective controlled trials (PCTs) and one cohort study. All studies examined at least two groups. There is Level 1 and Level 2 evidence supporting the use of specialized CBT protocols in persons with SCI for improving outcomes related to depression, anxiety, adjustment, and coping. Conclusions: CBT holds promise as an effective approach for persons with SCI experiencing depression, anxiety, adjustment, and coping problems. As CBT may involve many different components, it is important in the future to determine which of these elements alone or in combination is most effective in treating the emotional consequences of SCI. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
77.
Shefali Trivedi Yashwant Mehta K. Chandra P.S. Mishra 《Journal of Materials Processing Technology》2010,210(1):85-90
The present investigation shows the role of chromium in Fe–P binary and Fe–P–Cr ternary alloys. The compositions are characterized in terms of microstructure, porosity content, hardness and tensile properties. The alloys were made using a hot powder forging technique. In this process mild steel encapsulated powders were hot forged into slabs. Then the slabs were hot rolled and annealed to relieve the residual stresses. Densifications as high as 98.9% of theoretical density have been realized. Microstructures of these alloys consist of single-phase ferrite only. Both Fe–0.45P and Fe–0.45P–3Cr alloys showed very high strength. As forged and hot rolled Fe–0.45P alloy showed low elongation. It was observed that, the addition of Cr to Fe–P based alloys caused an increase in strength associated with the reduction in ductility. Alloys developed in the present investigation were capable of hot working to very thin gage of sheets and wires. 相似文献
78.
N. Mehta 《Current Opinion in Solid State & Materials Science》2010,14(5):95-106
The phenomenon of Meyer–Neldel rule (MNR) can occur in any situation which involves an activated process. However, the rule is still most commonly referred to in connection with diffusion and electrical conduction phenomena. As the rule still tends to exist in an indeterminate state between fully accepted physical law and unexplained correlation, this review presents a survey of relevant work done in this direction. The main objective of the review is to highlight the recent observations of MNR in chalcogenide glasses for different types of thermally activated phenomena and their consequences. 相似文献
79.
The present paper reports the composition dependence of pre-exponential factor and activation energy of non-isothermal crystallization in amorphous alloys of Cu x Ti100?x system using differential scanning calorimeter (DSC) technique. The applicability of Meyer-Neldel relation between the pre-exponential factor and activation energy of non-isothermal crystallization for amorphous alloys of Cu-Ti system was verified. 相似文献
80.