全文获取类型
收费全文 | 5279篇 |
免费 | 496篇 |
国内免费 | 83篇 |
专业分类
电工技术 | 10篇 |
综合类 | 253篇 |
化学工业 | 864篇 |
金属工艺 | 51篇 |
机械仪表 | 133篇 |
建筑科学 | 24篇 |
矿业工程 | 11篇 |
能源动力 | 25篇 |
轻工业 | 4072篇 |
水利工程 | 28篇 |
石油天然气 | 29篇 |
武器工业 | 2篇 |
无线电 | 61篇 |
一般工业技术 | 105篇 |
冶金工业 | 21篇 |
原子能技术 | 6篇 |
自动化技术 | 163篇 |
出版年
2024年 | 46篇 |
2023年 | 108篇 |
2022年 | 265篇 |
2021年 | 295篇 |
2020年 | 199篇 |
2019年 | 187篇 |
2018年 | 140篇 |
2017年 | 187篇 |
2016年 | 182篇 |
2015年 | 209篇 |
2014年 | 247篇 |
2013年 | 297篇 |
2012年 | 507篇 |
2011年 | 460篇 |
2010年 | 292篇 |
2009年 | 266篇 |
2008年 | 216篇 |
2007年 | 366篇 |
2006年 | 297篇 |
2005年 | 224篇 |
2004年 | 155篇 |
2003年 | 105篇 |
2002年 | 103篇 |
2001年 | 87篇 |
2000年 | 59篇 |
1999年 | 66篇 |
1998年 | 53篇 |
1997年 | 32篇 |
1996年 | 34篇 |
1995年 | 20篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 20篇 |
1991年 | 20篇 |
1990年 | 12篇 |
1989年 | 14篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有5858条查询结果,搜索用时 234 毫秒
71.
Bacterial polysaccharides and polyhydroxyalkanoates present physical and chemical characteristics that impart them diverse functional properties, including the ability to produce structures from nano- to macroscale (e.g., spheres, capsules, beads). Such structures may be specially designed to fulfill the requirements of specific applications in different areas, either alone or conjugated with other polymers by means of ionic interactions, hydrogen bonding, or chemical reactions. The interest on using such biomaterials has been increasing due to their unique functional properties, nontoxicity, biodegradability, and biocompatibility. The fields of application of bacterial polymers-based structures include drug delivery, biomedicine, food products, environment, and agriculture, among others. 相似文献
72.
N. Iguergaziz A. Boukhiar F.-Z. Djallouli A. Guebrili N.-E. Angar 《Chemical Engineering Communications》2019,206(4):524-534
Release characteristics of paracetamol from date (Phoenix dactylifera L., var. Mech-Degla) fruit tablets enriched and non-enriched with freeze-dried olive leaf extract (OLE) were studied. For this, two types of tablets (T) were obtained by direct compression: (1) T1 from P1-powder blend, containing 60% date powder (DP) and 40% paracetamol, and (2) T2 from P2-powder blend, containing 57% DP, 40% paracetamol, and 3% OLE. The release of paracetamol was studied in phosphate buffer (pH?6.8) and HCl solution (0.1N). Additionally, the oleuropein released was investigated in the case of T2-tablets. Based on obtained results, P1- and P2-powder blends showed acceptable flow properties in terms of Hausner’s ratio (1.30, in the case of P2) and angle of repose for both P1 (31 degrees) and P2 (33 degrees). Dissolution study showed that the released paracetamol achieved 80% after 70?min, whereas the oleuropein release was almost complete after 30?min. On the other hand, the Peppas model described correctly dissolution kinetics of both paracetamol (R2=?0.99) and oleuropein (R2=?0.89) whatever the applied dissolution medium. Furthermore, the presence of OLE in T2-tablets enhanced their microbiological shelf-life. 相似文献
73.
葛含静 《食品安全质量检测学报》2021,12(6):2394-2399
目的 优化水热法提取光皮木瓜(Chaenomeles sinensis)多糖的提取工艺条件,对光皮木瓜不溶性多糖的组成和结构进行分析。方法 预处理后的光皮木瓜样品经水热法提取、抽滤、冲洗,浓缩等操作,分别得到不溶性多糖、醇沉多糖和醇溶多糖,通过傅里叶变换红外光谱、扫描电子显微镜及X射线衍射分析不溶性多糖的组成和结构。 结果 多糖提取的较优条件为150 ℃/45 min,料液比1∶10 (W/V);温度对水热法提取效果影响显著,适当升高温度、延长提取时间和减少料液比有利于多糖提取;高温虽能促进半纤维素溶解,但无法使木质素和木聚糖降解;即使提取温度不同,光皮木不溶性多糖的结构差异也极小;水热法提取光皮木瓜多糖不会导致多糖的功能性基团变化,只改变多糖的化学组成。结论 该研究可为光皮木瓜多糖的结构与功能研究提供实验依据,也为陕西白河光皮木瓜资源的综合利用提供研究参考。 相似文献
74.
75.
Suriyan Supapvanich Rachaya Arkajak Ko Yalai 《International Journal of Food Science & Technology》2012,47(12):2662-2670
The effects of hot CaCl2 dips on postharvest quality and bioactive compounds of fresh‐cut sweet leaf bush were investigated. The vegetable was dipped in 0.5% or 1.0% (w/v) of CaCl2 solutions at 40 °C for 30 s and the control was the untreated sample. Hot CaCl2 dips significantly delayed the weight loss, maintained the overall quality and inhibited the wiltness (P < 0.05). Both hot CaCl2 dips had no effect on the changes in lightness (L*) and delayed the decrease in greenness (‐a*) and total chlorophyll content and the increase in both yellowness (b*) and carotenoid content. Hot CaCl2 dips enhanced total antioxidants, total phenolics content and both AsA‐POD and G‐POD activities from 38.6, 0.44, 15.2 and 22.4 at day 0 to 55.3, 0.55, 50.5 and 362.4 at day 8, respectively. Moreover, hot CaCl2 dips also delayed the loss of DPPH free radical scavenging activity, total flavonoid, ascorbic acid and CAT activity when compared to other treatments during storage. This study showed that hot CaCl2 dip maintains postharvest quality and enhanced bioactive compounds of fresh‐cut sweet leaf bush during storage. 相似文献
76.
Huali Hu Wenbiao Shen Pengxia Li 《International Journal of Food Science & Technology》2014,49(2):399-409
Here we investigated the effect of hydrogen sulphide (H2S) on postharvest quality of mulberry fruit and possible underlying mechanisms. Endogenous H2S content first increased after harvest and then decreased sharply with the process of ripening and senescence. A fumigation with H2S released from 0.8 mm NaHS solution could significantly enhance the endogenous H2S content by increasing the activities of D‐cysteine desulfhydrase and L‐cysteine desulfhydrase. NaHS could significantly slow down the ripening rate of mulberry fruit and reduce the respiratory intensity and anthocyanin content. Moreover, H2S fumigation was able to obviously delay or slow down the decreases in soluble protein, titratable acidity and ascorbate contents. Further results showed that activities of representative antioxidant enzymes in H2S‐treated sample were higher than those of control samples during storage, resulting in a decrease in superoxide anion production. Together, these results clearly indicate that H2S fumigation has a potential role in the preservation of mulberries. 相似文献
77.
为了有效提高渐变刚度钢板弹簧式轻型卡车的乘坐舒适性,根据弹簧受力与刚度和变形之间的关系,利用等频原理,建立了渐变刚度钢板弹簧力学特性解析计算模型,并利用钢板弹簧加载-卸载试验对所建立的模型的正确性进行了验证。基于1/2车辆行驶振动模型,利用MATLAB的Simulink工具箱,建立了考虑渐变刚度钢板弹簧力学特性的轻卡行驶振动仿真分析模型。最后,以人体振动舒适性最佳为目标,利用多岛遗传算法,建立了轻卡悬架系统阻尼参数仿真设计方法,并利用实车试验对所建立的轻卡悬架系统阻尼参数仿真设计方法的正确性进行了验证。上述研究为渐变刚度钢板弹簧式轻卡悬架系统参数的设计提供了有效参考。 相似文献
78.
Microencapsulation of bioactive compounds from mulberry (Morus alba L.) leaf extracts by protein–polysaccharide interactions
下载免费PDF全文
![点击此处可从《International Journal of Food Science & Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Methavee Peanparkdee Satoshi Iwamoto Chaleeda Borompichaichartkul Kiattisak Duangmal Ryo Yamauchi 《International Journal of Food Science & Technology》2016,51(3):649-655
Mulberry leaf extracts were generated using four concentrations of ethanol (50%, 60%, 70%, and 95% v/v). A 60% ethanolic mulberry leaf extract (60E) yielded a high total phenolic content (TPC) and antioxidant activity using 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging and a ferric reducing antioxidant power (FRAP) assay. Coating materials were derived using a combination of soy protein isolates (SPI) and low methoxyl (LM) pectin in a 1:1 ratio. The effect of various parameters on microencapsulation, such as pH (3.5, 4.0, and 4.5) and the concentration of coating materials (2.5, 5.0 and 7.5% w/v), was studied. Microcapsules produced using 60E as a core material at pH 4.0 with 7.5% of coating material showed a high encapsulation yield, encapsulation efficiency, TPC and antioxidant activity. 相似文献
79.
80.