全文获取类型
收费全文 | 500篇 |
免费 | 15篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 79篇 |
金属工艺 | 8篇 |
机械仪表 | 5篇 |
建筑科学 | 19篇 |
矿业工程 | 3篇 |
能源动力 | 12篇 |
轻工业 | 54篇 |
水利工程 | 6篇 |
石油天然气 | 10篇 |
无线电 | 36篇 |
一般工业技术 | 67篇 |
冶金工业 | 141篇 |
原子能技术 | 2篇 |
自动化技术 | 73篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 22篇 |
2012年 | 20篇 |
2011年 | 40篇 |
2010年 | 20篇 |
2009年 | 11篇 |
2008年 | 33篇 |
2007年 | 35篇 |
2006年 | 21篇 |
2005年 | 22篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 20篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有517条查询结果,搜索用时 16 毫秒
91.
Randy J. Mikula Vicente A. Munoz Vendy W. Lam 《Petroleum Science and Technology》2013,31(5-6):727-749
ABSTRACT Microscopic characterization of oil sands emulsions can be important in the prediction of processing characteristics and process yields in the extraction of oil from oil sands. The size distribution of the emulsion can determine how efficiently the oil can be separated from the water and by what means: mechanically or chemically. In addition, it is possible to characterize the nature of the dispersed phase by using fluorescence behaviour under an optical microscope or via x-ray analysis with a scanning electron microscope. In certain cases it is also possible to characterize the interface between the dispersed and the continuous phases. This paper presents results from our laboratory using microscopic techniques and illustrates their utility, not only for determining the morphology of these economically important emulsions, but also to characterize the composition of the interface itself. 相似文献
92.
McLean Peter D.; Whittal Maureen L.; Thordarson Dana S.; Taylor Steven; S?chting Ingrid; Koch William J.; Paterson Randy; Anderson Kent W. 《Canadian Metallurgical Quarterly》2001,69(2):205
This study examined the effects of cognitive-behavior therapy (CBT) compared with traditional behavior therapy (exposure and response prevention [ERP]) in the group treatment of obsessive-compulsive disorder. Of the 76 participants who started treatment, 38 were wait-listed for 3 months before treatment to assess possible course effects. Both treatments were superior to the control condition in symptom reduction, with ERP being marginally more effective than CBT by end of treatment and again at 3-month follow-up. In terms of clinically significant improvement, treatment groups were equivalent on the conclusion of treatment, but 3 months later significantly more ERP participants met criteria for recovered status. Only 1 of 7 belief measures changed with treatment improvement, and the extent of this cognitive change was similar between CBT and ERP groups. Discussion includes consideration of optimal formats for the delivery of different types of treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
93.
Hirst William; Phelps Elizabeth A.; Buckner Randy L.; Budson Andrew E.; Cuc Alexandru; Gabrieli John D. E.; Johnson Marcia K.; Lustig Cindy; Lyle Keith B.; Mather Mara; Meksin Robert; Mitchell Karen J.; Ochsner Kevin N.; Schacter Daniel L.; Simons Jon S.; Vaidya Chandan J. 《Canadian Metallurgical Quarterly》2009,138(2):161
More than 3,000 individuals from 7 U.S. cities reported on their memories of learning of the terrorist attacks of September 11, as well as details about the attack, 1 week, 11 months, and/or 35 months after the assault. Some studies of flashbulb memories examining long-term retention show slowing in the rate of forgetting after a year, whereas others demonstrate accelerated forgetting. This article indicates that (a) the rate of forgetting for flashbulb memories and event memory (memory for details about the event itself) slows after a year, (b) the strong emotional reactions elicited by flashbulb events are remembered poorly, worse than nonemotional features such as where and from whom one learned of the attack, and (c) the content of flashbulb and event memories stabilizes after a year. The results are discussed in terms of community memory practices. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
94.
95.
Comprehensive Review of Patulin Control Methods in Foods 总被引:1,自引:0,他引:1
Matthew M. Moake Olga I. Padilla‐Zakour Randy W. Worobo 《Comprehensive Reviews in Food Science and Food Safety》2005,4(1):8-21
The mycotoxin, patulin (4‐hydroxy‐4H‐furo [3, 2c] pyran‐2[6H]‐one), is produced by a number of fungi common to fruit‐ and vegetable‐based products, most notably apples. Despite patulin's original discovery as an antibiotic, it has come under heavy scrutiny for its potential negative health effects. Studies investigating these health effects have proved inconclusive, but there is little doubt as to the potential danger inherent in the contamination of food products by patulin. The danger posed by patulin necessitates its control and removal from foods products, creating a demand for handling and processing techniques capable of doing so, preferably at low cost to industry. With this being the case, much research has been devoted to understanding the basic chemical and biological nature of patulin, as well as its interaction within foods and food production. While past resarch has elucidated a great deal, patulin contamination continues to be a challenge for athe food industry. Here, we review in depth the past research on patulin with an emphasis upon its influence within the food industry, including its regulation, health effects, biosynthesis, detection, quantification, distribution within foods, and control, during the various stages of apple juice production. Finally, key areas where future patulin research should focus to best control the patulin contamination problem within the food industry are addressed. 相似文献
96.
Validity of the emotional Stroop task hinges on equivalence between the emotion and the control words in terms of lexical features related to word recognition. The authors evaluated the lexical features of 1,033 words used in 32 published emotional Stroop studies. Emotion words were significantly lower in frequency of use, longer in length, and had smaller orthographic neighborhoods than words used as controls. These lexical features contribute to slower word recognition and hence are likely to contribute to delayed latencies in color naming. The often-replicated slowdown in color naming of emotion words may be due, in part, to lexical differences between the emotion and control words used in the majority of such studies to date. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
97.
Lynn W. Maines Randy S. Schrecengost Yan Zhuang Staci N. Keller Ryan A. Smith Cecelia L. Green Charles D. Smith 《International journal of molecular sciences》2022,23(21)
Exposure to ionizing radiation (IR) is a lingering threat from accidental or terroristic nuclear events, but is also widely used in cancer therapy. In both cases, host inflammatory responses to IR damage normal tissue causing morbidity and possibly mortality to the victim/patient. Opaganib, a first-in-class inhibitor of sphingolipid metabolism, has broad anti-inflammatory and anticancer activity. Opaganib elevates ceramide and reduces sphingosine 1-phosphate (S1P) in cells, conditions that increase the antitumor efficacy of radiation while concomitantly suppressing inflammatory damage to normal tissue. Therefore, opaganib may suppress toxicity from unintended IR exposure and improve patient response to chemoradiation. To test these hypotheses, we first examined the effects of opaganib on the toxicity and antitumor activity of radiation in mice exposed to total body irradiation (TBI) or IR with partial bone marrow shielding. Oral treatment with opaganib 2 h before TBI shifted the LD75 from 9.5 Gy to 11.5 Gy, and provided substantial protection against gastrointestinal damage associated with suppression of radiation-induced elevations of S1P and TNFα in the small intestines. In the partially shielded model, opaganib provided dose-dependent survival advantages when administered 4 h before or 24 h after radiation exposure, and was particularly effective when given both prior to and following radiation. Relevant to cancer radiotherapy, opaganib decreased the sensitivity of IEC6 (non-transformed mouse intestinal epithelial) cells to radiation, while sensitizing PAN02 cells to in vitro radiation. Next, the in vivo effects of opaganib in combination with radiation were examined in a syngeneic tumor model consisting of C57BL/6 mice bearing xenografts of PAN02 pancreatic cancer cells and a cross-species xenograft model consisting of nude mice bearing xenografts of human FaDu cells. Mice were treated with opaganib and/or IR (plus cisplatin in the case of FaDu tumors). In both tumor models, the optimal suppression of tumor growth was attained by the combination of opaganib with IR (± cisplatin). Overall, opaganib substantially protects normal tissue from radiation damage that may occur through unintended exposure or cancer radiotherapy. 相似文献
98.
Randy Przybylla Christina Susanne Mullins Mathias Krohn Stefan Oswald Michael Linnebacher 《International journal of molecular sciences》2022,23(17)
Commonly used intestinal in vitro models are limited in their potential to predict oral drug absorption. They either lack the capability to form a tight cellular monolayer mimicking the intestinal epithelial barrier or the expression of cytochrome P450 3A4 (CYP3A4). The aim of this study was to establish a platform of colorectal cancer patient-derived cell lines for evaluation of human intestinal drug absorption and metabolism. We characterized ten 2D cell lines out of our collection with confluent outgrowth and long-lasting barrier forming potential as well as suitability for high throughput applications with special emphasis on expression and inducibility of CYP3A4. By assessment of the transepithelial electrical resistance (TEER) the cells barrier function capacity can be quantified. Very high TEER levels were detected for HROC60. A high basal CYP3A4 expression and function was found for HROC32. Eight cell lines showed higher CYP3A4 induction by stimulation via the vitamin D receptor compared to Caco-2 cells (5.1- to 16.8-fold change). Stimulation of the pregnane X receptor led to higher CYP3A4 induction in two cell lines. In sum, we identified the two cell lines HROC183 T0 M2 and HROC217 T1 M2 as useful tools for in vitro drug absorption studies. Due to their high TEER values and inducibility by drug receptor ligands, they may be superior to Caco-2 cells to analyze oral drug absorption and intestinal drug–drug interactions. Significance statement: Selecting appropriate candidates is important in preclinical drug development. Therefore, cell models to predict absorption from the human intestine are of the utmost importance. This study revealed that the human cell lines HROC183 T0 M2 and HROC217 T1 M2 may be better suited models and possess higher predictive power of pregnane X receptor- and vitamin D-mediated drug metabolism than Caco-2 cells. Consequently, they represent useful tools for predicting intestinal absorption and simultaneously enable assessment of membrane permeability and first-pass metabolism. 相似文献
99.
Randy Becker 《电子技术应用》2009,35(10)
<正> 在传统意义上的无线通信系统中,射频领域的模拟信号可使用模拟技术解调为同相(I)和正交(Q)分量。但在当今软件定义的无线技术时代,中频信号经过变频处理后通常会使用模数转换器(ADC)进行数字化处理,然后再将数字信号馈入基带进行解调和解码。现在,通过将信号发生器的输出频率设为目标中频来生成恰当的中频(IF)信 相似文献
100.
Abigail B. Snyder Megan N. Biango‐Daniels Kathie T. Hodge Randy W. Worobo 《Comprehensive Reviews in Food Science and Food Safety》2019,18(1):286-304
Fungal spoilage in processed foods remains a challenge for food manufacturers despite the increasing availability of diverse processing and formulation strategies used to control foodborne microorganisms. Physiological features of yeasts and molds contribute to their tolerance to thermal processing, acidity, desiccation, and oxygen and nutrient limitations. These features variably include growth form, cell wall structure, cytoplasmic composition, cell membrane‐bound proteins, and secretion of secondary metabolites. Collectively, these mechanisms contribute to the ability of fungi to disperse, survive, and propagate in highly restrictive food environments. The diversity of fungal growth and survival mechanisms has resulted in organisms adapted to nearly all food environments; although, only a small subset of fungi are particularly suited for spoilage of a given product. The relationship between the individual physiology and metabolic capabilities of a yeast or mold and the product's specific physicochemical attributes and processing history determines spoilage potential. Explicit characterization of the fungal features responsible for this extremotolerance contributes to more targeted and effective control strategies. 相似文献