全文获取类型
收费全文 | 3083篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 14篇 |
化学工业 | 132篇 |
金属工艺 | 6篇 |
机械仪表 | 11篇 |
建筑科学 | 37篇 |
矿业工程 | 1篇 |
能源动力 | 13篇 |
轻工业 | 72篇 |
水利工程 | 3篇 |
石油天然气 | 14篇 |
无线电 | 110篇 |
一般工业技术 | 134篇 |
冶金工业 | 2454篇 |
原子能技术 | 8篇 |
自动化技术 | 93篇 |
出版年
2022年 | 4篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 23篇 |
2012年 | 23篇 |
2011年 | 44篇 |
2010年 | 16篇 |
2009年 | 18篇 |
2008年 | 32篇 |
2007年 | 39篇 |
2006年 | 22篇 |
2005年 | 28篇 |
2004年 | 29篇 |
2003年 | 27篇 |
2002年 | 15篇 |
2001年 | 26篇 |
2000年 | 32篇 |
1999年 | 90篇 |
1998年 | 808篇 |
1997年 | 473篇 |
1996年 | 305篇 |
1995年 | 194篇 |
1994年 | 144篇 |
1993年 | 145篇 |
1992年 | 27篇 |
1991年 | 30篇 |
1990年 | 25篇 |
1989年 | 36篇 |
1988年 | 22篇 |
1987年 | 28篇 |
1986年 | 25篇 |
1985年 | 28篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 18篇 |
1981年 | 22篇 |
1980年 | 20篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 43篇 |
1976年 | 80篇 |
1975年 | 13篇 |
1974年 | 9篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 7篇 |
排序方式: 共有3102条查询结果,搜索用时 12 毫秒
21.
In this paper, we propose a maximum a posteriori framework for the super-resolution problem, i.e., reconstructing high-resolution images from shifted, rotated, low-resolution degraded observations. The main contributions of this work are two; first, the use of a new locally adaptive edge preserving prior for the super-resolution problem. Second an efficient two-step reconstruction methodology that includes first an initial registration using only the low-resolution degraded observations. This is followed by a fast iterative algorithm implemented in the discrete Fourier transform domain in which the restoration, interpolation and the registration subtasks of this problem are preformed simultaneously. We present examples with both synthetic and real data that demonstrate the advantages of the proposed framework. 相似文献
22.
C.E. AalsethA.R. Day D.A. HaasE.W. Hoppe B.J. HyronimusM.E. Keillor E.K. MaceJ.L. Orrell A. SeifertV.T. Woods 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,652(1):58-61
On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear explosion are a valuable signature of a Treaty violation. Argon-37 is produced by neutron interaction with calcium in soil, 40Ca(n,α)37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45 mBq/SCM in wholeair. 相似文献
23.
A rapid method for the estimation of available lysine in dried milk powder has been developed. Samples were treated with 2,4,6-trinitrobenzene sulfonic acid and then hydrolyzed with 6N HCl. The hydrolysate was purified and subjected to ascending thin layer chromatography to isolate xi-trinitophenyl lysine in pure form. The color was read at 346 nm in a specitrophotometer. 相似文献
24.
25.
The frequency and severity of CNSLD was studied in workers of an Hungarian firm (Ganz-Mavag) by means of questionnaire. Symptoms of CNSLD can be found more frequently in workers with air pollution than in those without. The symptoms of CNSLD show an age-dependence with regard to frequency and grade of severity, the single symptoms of CNSLD not occurring simultaneously and changing in their proportional frequency. 相似文献
26.
Streptokinase-streptodornase (SK-SD) induced immediate and delayed skin test reactions in a high proportion of patients with disorders in which beta-streptococcal infection may be involved. The P-K test and absorption experiments with antigen or anti-IgE suggested that the immediate reaction was mediated by specific IgE antibody against SK-SD. Furthermore, the ratio of specific IgE antibody against SK-SD to total IgE was roughly calculated to be 20 percent. Finally, the RAST technique was applied to detect specific IgE antibody against SK-SD which showed high radiocounts bound to SK-SD-coupled particles in the sera of nephrotic patients who had a strong immediate reaction against SK-SD and a severe disease state. 相似文献
27.
Examined racial E effects in counseling-like interviews employing the verbal operant-conditioning paradigm. The general objective was to determine whether significant differences in the conditionability of 12 Black and 12 White female college students, as measured by their emission of positive and negative self-reference emotional affect statements, would obtain when the verbal reinforcement was provided by 2 Black and 2 White Es. A postexperimental inquiry assessed Ss' perceptions of the interviews and their level of awareness of the Es' to influence their verbal behavior. While no definitive conclusions were reached, this study demonstrates that the verbal operant-conditioning paradigm can be used to investigate racial effects on verbal behavior in the counseling interview. Through the use of multiple, biracial Es and Ss, this study goes a step further than other verbal operant-conditioning studies that have explored racial E effects. The absence of significant differences in the E-S racial interaction suggests that race, per se, may not be the most important variable in the E-S (or counselor-client) relationship. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
29.
SC Sharma 《Canadian Metallurgical Quarterly》1976,64(4):597-600
Forearm skin blood flow was measured during external pressure loading in normal human subjects using 133Xe washout from intracutaneous injection sites. Pressures ranging between 5 and 150 mmHg were applied through a 3-cm-diameter disc placed over the site of flow determination. The pressure was maintained constant by a servo-controlled loading mechanism. Flow decreased with pressures from 5 to 10 and 30 to 150 mmHg, but remained constant with pressures from 10 to 30 mmHg. Reactive hyperemia occurred following removal of pressures of 90 mmHg or greater, but did not occur following removal of lower pressures. The pressure-flow curve for parasacral skin of paraplegic subjects closely paralleled the pressure-flow curve of normal skin at pressures tested: 5-15 mmHg. These data are interpreted to demonstrate autoregulation of skin blood flow. Autoregulation in parasacral skin of paraplegic subjects suggests a peripheral mechanism. The occurrence of hyperemia at pressures which exceed the ability of skin to autoregulate suggests that both autoregulation and post occlusion hyperemia may have the same mechanism. 相似文献
30.
SC Marks 《Canadian Metallurgical Quarterly》1976,146(3):331-338
The Clausen modification of the peripheral blood buffy coat leukocyte migration test was used to test patients with multiple sclerosis, normal subjects and patients with other neurologic diseases for cell-mediated immunity to commercial measles virus, purified nuclear core material from a human neurotropic strain of measles virus, as well as to commercial preparations of rubella, mumps and parainfluenza HA2. Leukocytes of multiple sclerosis patients showed significantly less mean inhibition of migration in the presence of both measles antigens, mumps and parainfluenza but no difference from controls when incubated with rubella. No correlation could be found between the degree of migration inhibition and concomitant serum anti-measles neutralization antibody titers to the same strain of virus. The use of purified viral antigens might result in more meaningful studies of the status of cellmediated immunity to viral antigens in multiple sclerosis. The relationship of our findings to other studies in this area and to the pathogenesis of multiple sclerosis is discussed. 相似文献