全文获取类型
收费全文 | 12062篇 |
免费 | 375篇 |
国内免费 | 16篇 |
专业分类
电工技术 | 129篇 |
综合类 | 18篇 |
化学工业 | 2531篇 |
金属工艺 | 202篇 |
机械仪表 | 209篇 |
建筑科学 | 635篇 |
矿业工程 | 64篇 |
能源动力 | 271篇 |
轻工业 | 1159篇 |
水利工程 | 135篇 |
石油天然气 | 52篇 |
无线电 | 821篇 |
一般工业技术 | 1793篇 |
冶金工业 | 2841篇 |
原子能技术 | 116篇 |
自动化技术 | 1477篇 |
出版年
2022年 | 92篇 |
2021年 | 189篇 |
2020年 | 159篇 |
2019年 | 144篇 |
2018年 | 174篇 |
2017年 | 173篇 |
2016年 | 221篇 |
2015年 | 174篇 |
2014年 | 268篇 |
2013年 | 682篇 |
2012年 | 468篇 |
2011年 | 586篇 |
2010年 | 435篇 |
2009年 | 457篇 |
2008年 | 523篇 |
2007年 | 517篇 |
2006年 | 431篇 |
2005年 | 346篇 |
2004年 | 328篇 |
2003年 | 341篇 |
2002年 | 305篇 |
2001年 | 210篇 |
2000年 | 186篇 |
1999年 | 214篇 |
1998年 | 245篇 |
1997年 | 194篇 |
1996年 | 167篇 |
1995年 | 195篇 |
1994年 | 171篇 |
1993年 | 176篇 |
1992年 | 161篇 |
1991年 | 117篇 |
1990年 | 150篇 |
1989年 | 167篇 |
1988年 | 142篇 |
1987年 | 146篇 |
1986年 | 143篇 |
1985年 | 191篇 |
1984年 | 168篇 |
1983年 | 155篇 |
1982年 | 160篇 |
1981年 | 162篇 |
1980年 | 120篇 |
1979年 | 158篇 |
1978年 | 153篇 |
1977年 | 138篇 |
1976年 | 122篇 |
1975年 | 126篇 |
1974年 | 116篇 |
1973年 | 122篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Shanshan Zhuang Wenxiong Zheng Yunong Na Naiyi Chen Fan Gong Bingxuan Huang Stephen Brennan Charles Congyi Liu Jian Cheng Lukai Ma Huifan Liu 《International Journal of Food Science & Technology》2022,57(2):1093-1103
The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results. 相似文献
2.
Jean-Claude Malela-Majika Sandile Charles Shongwe Olatunde Adebayo Adeoti 《Quality and Reliability Engineering International》2021,37(8):3314-3322
The sensitivity of a monitoring scheme depends on many factors including the variance of the charting statistic which is very important in the computation of the control limits. This paper discusses the computation of the variance of the recently proposed hybrid homogeneously weighted moving average (HHWMA) scheme which was based on an incorrect assumption. The correct variance is used to evaluate the run-length characteristics of the HHWMA scheme. It is observed that the incorrect variance has a significant impact on the sensitivity (or performance) of the HHWMA scheme. 相似文献
3.
Anne-Margarethe Enge Florian Kaltner Christoph Gottschalk Albert Braeuning Stefanie Hessel-Pras 《International journal of molecular sciences》2021,22(8)
1,2-unsaturated pyrrolizidine alkaloids (PAs) are secondary plant metabolites occurring as food contaminants that can cause severe liver damage upon metabolic activation in hepatocytes. However, it is yet unknown how these contaminants enter the cells. The role of hepatic transporters is only at the beginning of being recognized as a key determinant of PA toxicity. Therefore, this study concentrated on assessing the general mode of action of PA transport in the human hepatoma cell line HepaRG using seven structurally different PAs. Furthermore, several hepatic uptake and efflux transporters were targeted with pharmacological inhibitors to identify their role in the uptake of the PAs retrorsine and senecionine and in the disposition of their N-oxides (PANO). For this purpose, PA and PANO content was measured in the supernatant using LC-MS/MS. Also, PA-mediated cytotoxicity was analyzed after transport inhibition. It was found that PAs are taken up into HepaRG cells in a predominantly active and structure-dependent manner. This pattern correlates with other experimental endpoints such as cytotoxicity. Pharmacological inhibition of the influx transporters Na+/taurocholate co-transporting polypeptide (SLC10A1) and organic cation transporter 1 (SLC22A1) led to a reduced uptake of retrorsine and senecionine into HepaRG cells, emphasizing the relevance of these transporters for PA toxicokinetics. 相似文献
4.
5.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
6.
7.
8.
Qin-yu Zhou Shan Zhao Yan-yan Huang Jin-shuang Hu Jia-hua Kuang Dong-mei Liu Charles S. Brennan 《International Journal of Food Science & Technology》2021,56(6):2992-3003
Yogurt preserves and enhances nutritional value of milk. In this study, we have compared several strains to determine the physicochemical, sensory, rheological and aroma characteristics of different yogurts. We used Lactobacillus gasseri LGZ 1029 (LG), commercial probiotic L. rhamnosus (LGG) and traditional fermentation strains Streptococcus thermophilus and L. bulgaricus (SL). Results showed that the flavour and texture characteristics of mixed-strain yogurts were obviously better than in single-strain yogurts. Addition of LG increased pseudoplastic behaviour, as shown by Herschel–Bulkley model analysis of rheological behaviour. The LG + SL group also had both the highest viscosity consistency index and thickening ability. In addition, a total of 57 volatile compounds were detected in yogurts and the fermentation with the addition of LG was mainly affected by ketones. Our study suggested that a yogurt with new attributes can be produced by using LGZ 1029. 相似文献
9.
Shamila Vibhushan Manuela Bratti Juan Eduardo Montero-Hernndez Alaa El Ghoneimi Marc Benhamou Nicolas Charles Eric Daugas Ulrich Blank 《International journal of molecular sciences》2021,22(1)
A sizable part (~2%) of the human genome encodes for proteases. They are involved in many physiological processes, such as development, reproduction and inflammation, but also play a role in pathology. Mast cells (MC) contain a variety of MC specific proteases, the expression of which may differ between various MC subtypes. Amongst these proteases, chymase represents up to 25% of the total proteins in the MC and is released from cytoplasmic granules upon activation. Once secreted, it cleaves the targets in the local tissue environment, but may also act in lymph nodes infiltrated by MC, or systemically, when reaching the circulation during an inflammatory response. MC have been recognized as important components in the development of kidney disease. Based on this observation, MC chymase has gained interest following the discovery that it contributes to the angiotensin-converting enzyme’s independent generation of angiotensin II, an important inflammatory mediator in the development of kidney disease. Hence, progress regarding its role has been made based on studies using inhibitors but also on mice deficient in MC protease 4 (mMCP-4), the functional murine counterpart of human chymase. In this review, we discuss the role and actions of chymase in kidney disease. While initially believed to contribute to pathogenesis, the accumulated data favor a more subtle view, indicating that chymase may also have beneficial actions. 相似文献
10.