全文获取类型
收费全文 | 3806篇 |
免费 | 203篇 |
国内免费 | 35篇 |
专业分类
电工技术 | 60篇 |
综合类 | 67篇 |
化学工业 | 828篇 |
金属工艺 | 165篇 |
机械仪表 | 151篇 |
建筑科学 | 201篇 |
矿业工程 | 42篇 |
能源动力 | 247篇 |
轻工业 | 524篇 |
水利工程 | 22篇 |
石油天然气 | 38篇 |
武器工业 | 2篇 |
无线电 | 205篇 |
一般工业技术 | 573篇 |
冶金工业 | 347篇 |
原子能技术 | 48篇 |
自动化技术 | 524篇 |
出版年
2024年 | 20篇 |
2023年 | 41篇 |
2022年 | 75篇 |
2021年 | 108篇 |
2020年 | 136篇 |
2019年 | 119篇 |
2018年 | 164篇 |
2017年 | 146篇 |
2016年 | 175篇 |
2015年 | 101篇 |
2014年 | 168篇 |
2013年 | 387篇 |
2012年 | 202篇 |
2011年 | 206篇 |
2010年 | 174篇 |
2009年 | 220篇 |
2008年 | 174篇 |
2007年 | 159篇 |
2006年 | 126篇 |
2005年 | 80篇 |
2004年 | 94篇 |
2003年 | 115篇 |
2002年 | 161篇 |
2001年 | 125篇 |
2000年 | 64篇 |
1999年 | 55篇 |
1998年 | 131篇 |
1997年 | 69篇 |
1996年 | 52篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 5篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1965年 | 3篇 |
排序方式: 共有4044条查询结果,搜索用时 15 毫秒
101.
Alper??nen?Email author Meltem?Serdaro?lu K?yalbek?Abdraimov 《European Food Research and Technology》2004,218(2):114-117
Longissimus dorsi (LD) muscles obtained from young bull carcasses (Holstein Friesian) were marinated, using solutions containing 0.5% sodium tripolyphosphate (STP), 0.5% dicalciumhydrogen phosphate (CHP) and 0.5% citric acid (CA). All solutions, including a blank, contained 2% NaCl. Expressible moisture, cooking loss, marinade uptake, area gain (increase in slice size), colour coordinate values (L*, a*, b*), marinade and meat pH, and the textural properties of samples were evaluated. Marinating with STP and CHP solutions resulted lower cooking losses. Marinade uptake and area gain were lower for control steaks and steaks marinated with the CA solution. The highest lightness was found in steaks marinated with the CA solution. Steaks marinated with STP and CHP solutions were darker. The CA solution resulted in yellowness of steaks. All treatments significantly affected hardness, chewiness and resilience values of steaks. The lowest hardness value was found in steaks marinated with CA. STP and CHP treatments also improved tenderness. 相似文献
102.
Polyphenol oxidase (PPO) obtained from wheat bran catalyzed the oxidation of 4-methyl catechol. Phenolic compounds found naturally in crude extract played role as an endogeneous substrate and activity of crude extract needed correction. Activity versus enzyme concentration gave a linear plot at high substrate concentration whereas a nonlinear plot was obtained at low substrate concentration which proved the presence of endogeneous substrate. Adsorption on celite and extraction with polyvinylpyrrolidone (PVPP) caused the removal of phenols. Adsorption of PPO on celite yielded a 4-fold increase in specific activity whereas extraction with PVPP yielded a 2.5-fold increase in specific activity compared to the crude extract. The kinetics of PPO catalyzed oxidation obeyed Michaelis-Menten model; Km and Vmax values were found as 218 mM and 99 microM/min, respectively. The enzyme was inhibited by ethyl alcohol, dithiothreitol (DTT) and isoproterenol and exhibited heat stability up to a temperature of 90 degrees C. The optimum pH of the enzyme was found to be 5.0. 相似文献
103.
The aim of this study was to determine the levels of essential, trace and toxic elements, such as K, Ca, Fe, Cu, Al, Ni, Sn, Pb and Cd in citrus honeys from different regions (industrialized and nonindustrialized) of Hatay, Turkey. K, Ca, Na and Mg were the most abundant elements, with mean contents of 363.5, 256.6, 88.1 and 37.7 mg/kg, respectively. The trace element mean contents ranged between 0.032 and 15.58 mg/kg. Significant differences in Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr levels were observed between two different regions. The findings that Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr contents in citrus honeys from industrialized regions were higher than citrus honeys from non-industrialized regions indicate that the honeys were affected by industrial pollution. Chemometric methods were applied to classify honey according to mineral content. Cluster analysis showed three clusters corresponding to the three different regions. 相似文献
104.
Fatma Tosun Çiğdem Akyüz Kızılay Kevser Erol Fatma Sultan Kılıç Mine Kürkçüoğlu Kemal Hüsnü Can Başer 《Food chemistry》2008
The anticonvulsant activity of furanocoumarins, coumarin mixture and the essential oil obtained from the fruits of Heracleum crenatifolium was examined against maximal electroshock (MES)-induced seizures in mice. Bergapten showed significant anticonvulsant activity. The furanocoumarins isolated from the fruits of the plant were identified using thin-layer chromatography, melting points and spectroscopic methods (IR, MS, 1H NMR) as isobergapten (1), pimpinellin (2), bergapten (3), isopimpinellin (4), sphondin (5) and byak-angelicol (6). The essential oil content of the fruits were found as 5.5%. Twenty-two compounds representing 99.3% of the essential oil obtained from the fruits of H. crenatifolium were determined and the major components were identified as octanol and octyl acetate (3.1% and 88.4% respectively) by GC and GC–MS. 相似文献
105.
This study aimed to evaluate the physicochemical, chemical, rheological, sensorial and microbiological properties of yoghurt enriched with polyunsaturated fatty acids (PUFAs). The PUFA‐enriched yoghurt was prepared with walnut slurry (10%?50%) and skimmed milk (50%?90%). Compared with the control yoghurt, it contained a lower content of protein, potassium, sodium and phosphorus, and a higher content of fat, iron, magnesium and zinc. Moreover, it exhibited a lower syneresis value and a higher water‐holding capacity value. Its fat was rich in omega fatty acids, mainly linoleic and linolenic acids. These research findings revealed that walnut slurry could be used in yoghurt manufacture to develop fermented milk products as functional foods, especially when enriched with omega fatty acids. 相似文献
106.
Unal Yesilgul Fatih Ungan Serpil ?akiro?lu Carlos Duque Miguel Mora-Ramos Esin Kasapoglu Huseyin Sari Ismail S?kmen 《Nanoscale research letters》2012,7(1):586
Using a variational approach, we have investigated the effects of the magnetic field, the impurity position, and the nitrogen and indium concentrations on impurity binding energy in a Ga1−xInxNyAs1−y/GaAs quantum well. Our calculations have revealed the dependence of impurity binding on the applied magnetic field, the impurity position, and the nitrogen and indium concentrations. 相似文献
107.
Kübra Purutolu Hümeyra spirli Mustafa Onur Yüzer Hüseyin Serencam Enes Dertli 《International Journal of Dairy Technology》2020,73(1):57-66
Traditional kefir grains were collected from distinct parts of Turkey, and their microbial profile was determined. A wide bacterial biota was observed formed by distinct lactic acid bacteria (LAB) in which Lactococcus lactis strains appeared to be dominant. Yeast species were also identified in kefir grains. Significant levels of antifungal and antibacterial activities were monitored in kefir isolates. All tested LAB produced an exopolysaccharide (EPS) containing glucose and galactose, and some strains formed a fructan‐type EPS. Importantly, low levels of antibiotic resistance were observed among the kefir isolates. 相似文献
108.
Abdullah Akdoğan Oğuz Gürsoy 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2020,37(3):391-400
ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are ingested with foods and cause toxicities for humans. Yoghurt is one of the main foods that mediate PAH ingestion. Yan?k yoghurt, a traditional strained yoghurt, can contain PAHs due to its production process. Therefore, the concentration and types of four polycyclic aromatic hydrocarbons were determined by gas chromatography-mass spectrometry (GC-MS). Yan?k yoghurt samples were collected from different shops in Denizli, Turkey. For the method validation, the Eurachem guide (second edition) was adopted. Accordingly, linearity, working range, limits of detection (LOD), quantification (LOQ), precision and trueness values were set. Due to the selected validation parameters, the limit for detection was between 0.03 ng g?1and 0.05 ng g?1while the limit for quantification was between 0.10 ng g?1 and 0.16 ng g?1. Recovery rates higher than 83.80 % were obtained for four PAHs at two spiked concentrations (2.0 and 5.0 ng g?1). Five Yan?k yoghurt samples and one commercial concentrated yoghurt sample were successfully analysed using the validated method. 相似文献
109.
110.
【摘要】 目的 探讨不同栓塞剂治疗肝巨大海绵状血管瘤中的疗效。方法 2008—2010年经诊断明确的肝海绵状血管瘤30例,行介入栓塞治疗,根据栓塞剂不同分为两组,即平阳霉素碘油乳剂(PLE)联合海藻酸钠微球(KMG)组(A组,15例)及(PLE)组(B组,15例),术后1、3、6、12 个月进行CT 检查以评价疗效。结果 两组术后成功率均达100%,A、B两组所用PLE剂量分别为(10.9 ± 5.2)ml、(11.4 ± 4.9)ml,两者差异无统计学意义(P > 0.05),术后第1、3、6个月复查CT,A组瘤体缩小率在50%以上者为分别为9、11、14例,B组分别为0、3、5例(P < 0.05)。术后1周A组患者疼痛较B组明显,差异有统计学意义(P < 0.05),术后两组部分患者有轻度肝功能异常,主要表现在转氨酶升高,对症处理后恢复正常,经问卷随访A组满意度较B组高。结论 经肝动脉注入PLE治疗肝巨大血管瘤安全、有效, PLE联合KMG组瘤体缩小主要集中在术后第1、3个月内,见效快,但疼痛较PLE组明显。 相似文献