全文获取类型
收费全文 | 1674篇 |
免费 | 117篇 |
专业分类
电工技术 | 4篇 |
综合类 | 4篇 |
化学工业 | 362篇 |
金属工艺 | 10篇 |
机械仪表 | 23篇 |
建筑科学 | 65篇 |
矿业工程 | 4篇 |
能源动力 | 22篇 |
轻工业 | 203篇 |
水利工程 | 26篇 |
石油天然气 | 3篇 |
武器工业 | 1篇 |
无线电 | 117篇 |
一般工业技术 | 272篇 |
冶金工业 | 466篇 |
原子能技术 | 27篇 |
自动化技术 | 182篇 |
出版年
2023年 | 15篇 |
2022年 | 23篇 |
2021年 | 80篇 |
2020年 | 31篇 |
2019年 | 35篇 |
2018年 | 42篇 |
2017年 | 36篇 |
2016年 | 65篇 |
2015年 | 45篇 |
2014年 | 66篇 |
2013年 | 90篇 |
2012年 | 82篇 |
2011年 | 126篇 |
2010年 | 105篇 |
2009年 | 87篇 |
2008年 | 82篇 |
2007年 | 91篇 |
2006年 | 54篇 |
2005年 | 59篇 |
2004年 | 61篇 |
2003年 | 37篇 |
2002年 | 30篇 |
2001年 | 25篇 |
2000年 | 30篇 |
1999年 | 23篇 |
1998年 | 43篇 |
1997年 | 42篇 |
1996年 | 24篇 |
1995年 | 26篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 14篇 |
1987年 | 15篇 |
1986年 | 11篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1976年 | 9篇 |
1975年 | 10篇 |
1973年 | 7篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1908年 | 4篇 |
排序方式: 共有1791条查询结果,搜索用时 31 毫秒
141.
Stephanie Clark Carl K. Winter 《Comprehensive Reviews in Food Science and Food Safety》2015,14(5):634-643
Diacetyl, noted for its appealing butter‐like aroma, is present naturally in many foods, and humans have been exposed to it since the beginning of civilization. The advent of microwave (MW) cooking technology has led to the development of a significant market for MW popcorn, to which diacetyl and other flavoring compounds have been frequently added. Based upon reported associations between diacetyl inhalation and lung disease in employees of MW popcorn processing facilities, a very conservative safe level of occupational exposure to diacetyl has been proposed by the American Conference of Governmental Industrial Hygienists. Yet there is conflicting evidence that diacetyl causes lung disease in workers, and no evidence to condemn diacetyl as the cause of lung problems in MW popcorn consumers. Consumer dietary exposure to diacetyl in foods is below levels of health concern while common airborne levels of diacetyl from MW popcorn are far below the conservatively established limit to protect workers. 相似文献
142.
143.
S. Reich G. Leitus R. Popovitz-Biro A. Goldbourt S. Vega 《Journal of Superconductivity and Novel Magnetism》2009,22(4):343-346
Magnetic susceptibility measurements of WO3 crystals hydrogen doped on the surface suggest 2D local non-percolated superconductivity with an onset temperature of 120 K.
Observed zero field cooled vs. field cooled magnetization response is characteristic of type II superconductivity. The diamagnetic
response at the critical temperature is field dependent, and is suppressed by a magnetic field of ∼1700 Oe. 相似文献
144.
Tomoko I. Hooper Samar F. DeBakey Stephanie Pratt 《Accident; analysis and prevention》2010,42(1):261-268
The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (<27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect. 相似文献
145.
Dingzheng Yang Andrew N. Hrymak Stephanie Kedzior 《Journal of the American Oil Chemists' Society》2013,90(11):1743-1750
Kinetics of isothermal crystallization of hydrogenated castor oil in water emulsions exhibiting multiple crystal morphologies have been studied experimentally by DSC and polarized light microscopy. The induction time of nucleation increases with the increase of the isothermal temperature under which crystallization occurred. Crystal growth has been observed by microscopy showing that both crystal morphologies, fibers and rosettes, grow linearly at the initial stage of crystallization and then slow down to reach a plateau value. The Avrami model, which has been widely used in kinetics studies of triacylglycerol systems, was employed to fit experimental results at different isothermal temperatures. It was found that experimental trends could be captured by introducing the volume fraction of each type of morphology into three-dimensional and one-dimensional full Avrami models. 相似文献
146.
Madon Stephanie; Guyll Max; Buller Ashley A.; Scherr Kyle C.; Willard Jennifer; Spoth Richard 《Canadian Metallurgical Quarterly》2008,95(2):369
This research examined whether self-fulfilling prophecy effects are mediated by self-verification, informational conformity, and modeling processes. The authors examined these mediational processes across multiple time frames with longitudinal data obtained from two samples of mother-child dyads (N? = 486; N? = 287), with children's alcohol use as the outcome variable. The results provided consistent support for the mediational process of self-verification. In both samples and across several years of adolescence, there was a significant indirect effect of mothers' beliefs on children's alcohol use through children's self-assessed likelihood of drinking alcohol in the future. Comparatively less support was found for informational conformity and modeling processes as mediators of mothers' self-fulfilling effects. The potential for self-fulfilling prophecies to produce long-lasting changes in targets' behavior via self-verification processes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
147.
148.
A novel strategy is described for the preparation of highly sensitive molecularly imprinted (MIPs) sensors for dopamine. It combines mercaptobenzene diazonium salt as a coupling agent for immobilizing gold nanoparticles to gold electrodes and benzoyl benzene diazonium salt as photoinitiator of radical polymerization at the said gold nanoparticle-decorated gold electrodes. The MIP films were prepared by surface-initiated photopolymerization (SIPP) of methacrylic acid (MAA) as functional monomer (F) for dopamine (DA) the template molecule (T), and ethylene glycol dimethacrylate (EGDMA), the crosslinker (C). Dimethylaniline was employed as a hydrogen donor. The specificity and selectivity were demonstrated by square wave voltammetry (SWV). The detection limit was 0.35 nmol L-1 (0.054 ng mL−1). The sensor layers are stable and adherent to the surface through aryl layers. The originality and advantage of the process lie in the use of aryl diazonium salt as coupling agents for anchroring nanoparticles and MIP layers to the electrode surface in a simple and efficient way which ensures high sensing performance together with good surface-MIP adhesion. The same strategy can be extended to a broad range of templates. 相似文献
149.
Renewable power supply systems have been a natural choice for many of Australia’s small remote aboriginal communities where the costs of diesel fuel are high. The results have been mixed. This is partially due to design factors, but more importantly due to community acceptance of these technologically complex systems and the maintenance arrangements with the community power station operators and local resource agencies. This paper looks at some of the issues to consider in the selection, design, installation and maintenance of appropriate hybrid power stations for smaller remote aboriginal communities. 相似文献
150.
<正>关于双组分纤维纺丝技术的第一批专利发表于20世纪40年代早期。从20世纪60年代中期开始,聚合物业界倾向于采用聚合物共混和混合物以改进材料的性能。双组分纤维由两种聚合物成分组成,它们彼此并列或互相缠绕。双组分纤维纺丝可 相似文献