全文获取类型
收费全文 | 51927篇 |
免费 | 2934篇 |
国内免费 | 163篇 |
专业分类
电工技术 | 727篇 |
综合类 | 66篇 |
化学工业 | 11359篇 |
金属工艺 | 2235篇 |
机械仪表 | 3419篇 |
建筑科学 | 1143篇 |
矿业工程 | 26篇 |
能源动力 | 2262篇 |
轻工业 | 4087篇 |
水利工程 | 280篇 |
石油天然气 | 90篇 |
武器工业 | 2篇 |
无线电 | 8248篇 |
一般工业技术 | 11144篇 |
冶金工业 | 3972篇 |
原子能技术 | 700篇 |
自动化技术 | 5264篇 |
出版年
2024年 | 52篇 |
2023年 | 592篇 |
2022年 | 911篇 |
2021年 | 1542篇 |
2020年 | 1118篇 |
2019年 | 1238篇 |
2018年 | 1499篇 |
2017年 | 1499篇 |
2016年 | 1834篇 |
2015年 | 1379篇 |
2014年 | 2212篇 |
2013年 | 3157篇 |
2012年 | 3441篇 |
2011年 | 4136篇 |
2010年 | 2986篇 |
2009年 | 3093篇 |
2008年 | 2927篇 |
2007年 | 2289篇 |
2006年 | 2125篇 |
2005年 | 1811篇 |
2004年 | 1652篇 |
2003年 | 1592篇 |
2002年 | 1413篇 |
2001年 | 1196篇 |
2000年 | 1066篇 |
1999年 | 973篇 |
1998年 | 1596篇 |
1997年 | 1023篇 |
1996年 | 840篇 |
1995年 | 581篇 |
1994年 | 491篇 |
1993年 | 418篇 |
1992年 | 304篇 |
1991年 | 295篇 |
1990年 | 274篇 |
1989年 | 257篇 |
1988年 | 216篇 |
1987年 | 175篇 |
1986年 | 132篇 |
1985年 | 125篇 |
1984年 | 99篇 |
1983年 | 65篇 |
1982年 | 39篇 |
1981年 | 40篇 |
1980年 | 32篇 |
1979年 | 33篇 |
1978年 | 32篇 |
1977年 | 43篇 |
1976年 | 65篇 |
1975年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Changmo Kim Izhar Livne‐Bar Karsten Gronert Jeremy M. Sivak 《Molecular nutrition & food research》2020,64(4)
Lipoxins (LXs) are autacoids, specialized proresolving lipid mediators (SPMs) acting locally in a paracrine or autocrine fashion. They belong to a complex superfamily of dietary small polyunsaturated fatty acid (PUFA)–metabolites, which direct potent cellular responses to resolve inflammation and restore tissue homeostasis. Together, these SPM activities have been intensely studied in systemic inflammation and acute injury or infection, but less is known about LX signaling and activities in the central nervous system. LXs are derived from arachidonic acid, an omega‐6 PUFA. In addition to well‐established roles in systemic inflammation resolution, they have increasingly become implicated in regulating neuroinflammatory and neurodegenerative processes. In particular, chronic inflammation plays a central role in Alzheimer's disease (AD) etiology, and dysregulated LX production and activities have been reported in a variety of AD rodent models and clinical tissue samples, yet with complex and sometimes conflicting results. In addition, reduced LX production following retinal injury has been reported recently by the authors, and an intriguing direct neuronal activity promoting survival and homeostasis in retinal and cortical neurons is demonstrated. Here, the authors review and clarify this growing literature and suggest new research directions to further elaborate the role of lipoxins in neurodegeneration. 相似文献
43.
A. A. Babenko V. I. Zhuchkov L. A. Smirnov A. V. Sychev A. A. Akberdin A. S. Kim M. F. Vitushchenko A. A. Dobromilov 《Steel in Translation》2015,45(11):883-886
A technology for slag formation in the ladle–furnace unit is considered; the slag is based on the CaO–SiO2–MgO–Al2O3–B2O3 system. This technology permits both microalloying of the steel with boron (reduced from the oxide phase) and desulfurization of the steel. The resulting boron content in the steel is 0.001–0.008%; the sulfur content in low-alloy steel and pipe steel is low (0.004–0.010%); and the consumption of manganese ferroalloys is reduced to 0.5 kg/t for 08кп steel and 1.4 kg/t for 09Г2C steel. In addition, the proposed technology increases the strength of the rolled steel, without loss in its plasticity; and reduces the environmental impact thanks to the replacement of fluorspar by colemanite. 相似文献
44.
Manjunatha S. Muttigi Byoung Ju Kim Bogyu Choi Inbo Han Hansoo Park Soo-Hong Lee 《International journal of molecular sciences》2020,21(23)
Adipose-derived mesenchymal stromal cells (Ad-MSCs) are a promising tool for articular cartilage repair and regeneration. However, the terminal hypertrophic differentiation of Ad-MSC-derived cartilage is a critical barrier during hyaline cartilage regeneration. In this study, we investigated the role of matrilin-3 in preventing Ad-MSC-derived chondrocyte hypertrophy in vitro and in an osteoarthritis (OA) destabilization of the medial meniscus (DMM) model. Methacrylated hyaluron (MAHA) (1%) was used to encapsulate and make scaffolds containing Ad-MSCs and matrilin-3. Subsequently, the encapsulated cells in the scaffolds were differentiated in chondrogenic medium (TGF-β, 1–14 days) and thyroid hormone hypertrophic medium (T3, 15–28 days). The presence of matrilin-3 with Ad-MSCs in the MAHA scaffold significantly increased the chondrogenic marker and decreased the hypertrophy marker mRNA and protein expression. Furthermore, matrilin-3 significantly modified the expression of TGF-β2, BMP-2, and BMP-4. Next, we prepared the OA model and transplanted Ad-MSCs primed with matrilin-3, either as a single-cell suspension or in spheroid form. Safranin-O staining and the OA score suggested that the regenerated cartilage morphology in the matrilin-3-primed Ad-MSC spheroids was similar to the positive control. Furthermore, matrilin-3-primed Ad-MSC spheroids prevented subchondral bone sclerosis in the mouse model. Here, we show that matrilin-3 plays a major role in modulating Ad-MSCs’ therapeutic effect on cartilage regeneration and hypertrophy suppression. 相似文献
45.
Choi HyungSeok Kim ChanHyung Choi Hyuk Lee JaeHwan 《Food science and biotechnology》2021,30(11):1435-1443
Food Science and Biotechnology - Buah merah oil and red palm oil are red colored and unrefined edible oils. Because of this color characteristic, measuring acid value by titration method can be... 相似文献
46.
Properties and applications of β‐glycosidase from Bacteroides thetaiotaomicron that specifically hydrolyses isoflavone glycosides
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)
Da‐Hye Byun Hye‐Jeong Choi Hye‐Won Lee Hye‐Yeon Jeon Woo‐Jae Choung Jae‐Hoon Shim 《International Journal of Food Science & Technology》2015,50(6):1405-1412
To modify the glycan part of glycosides, the gene encoding β‐glycosidase was cloned from Bacteroides thetaiotaomicron VPI‐5482. The cloned gene, bt_1780, was expressed in Escherichia coli MC1061 and the expressed enzyme was purified using Ni‐NTA affinity chromatography. The purified enzyme, BTBG, showed optimal activity at 50 °C and pH 5.5. Interestingly, this enzyme did not have any hydrolysing activity on ordinary β‐linkage–containing substrates such as xylobiose, lactose and cello‐oligosaccharide, but specifically hydrolysed isoflavone glycosides such as daidzin, genistin and glycitin. Compared to a commercial beta glucosidase, BTBG selectively hydrolysed isoflavone glycosides in soybean extract mixture solution. These results suggest that BTBG may be a specialized enzyme for the hydrolysis of glycosides and that the substrate specificity of BTBG is applicable for the bioconversion of isoflavone glycosides in the food industry. 相似文献
47.
Peer-to-Peer Networking and Applications - Recently, as the P2P service environment repeats evolution, its usage in mobile is rapidly increasing. Applications are being developed in various mobile... 相似文献
48.
49.
50.
Bioactive compounds and antioxidant activities of the Korean lotus leaf (Nelumbo nucifera) condiment: volatile and nonvolatile metabolite profiling during fermentation
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)
Recent studies have shown that lotus (Nelumbo nucifera) leaf has various pharmacological effects. However, there have been no scientific investigations into these leaves as a fermented crude liquid. This study compared the in vitro antioxidant capacity of lotus leaf‐fermented broth (LLFB) with that of 57° Brix sugar broth (SB) as a control over a period of 6 months based on 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging activity, ferric ion reducing power, superoxide dismutase‐like activity, tyrosinase inhibition and nitrite scavenging activity. The dominant species during fermentation process were Leuconostoc lactis and Saccharomyces cerevisiae for LLFB. A total of thirty‐six metabolites such as alkaloids, fatty acids, organic acids, phenolics, sugar and sugar derivatives, ethyl esters and monoterpenoids differed between SB and LLFB using gas chromatography–mass spectrometry. Meanwhile, nine volatile compounds in LLFB contributed pleasant, slightly sweetish and fruity odour of condiment and sensory evaluation score of 4.06 ± 1.52 in the proportion of 1:9 LLFB/water. 相似文献