全文获取类型
收费全文 | 1047篇 |
免费 | 153篇 |
国内免费 | 140篇 |
专业分类
电工技术 | 26篇 |
综合类 | 58篇 |
化学工业 | 348篇 |
金属工艺 | 7篇 |
机械仪表 | 51篇 |
建筑科学 | 16篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
轻工业 | 150篇 |
水利工程 | 2篇 |
石油天然气 | 13篇 |
武器工业 | 2篇 |
无线电 | 77篇 |
一般工业技术 | 89篇 |
冶金工业 | 22篇 |
原子能技术 | 83篇 |
自动化技术 | 387篇 |
出版年
2024年 | 2篇 |
2023年 | 26篇 |
2022年 | 39篇 |
2021年 | 64篇 |
2020年 | 59篇 |
2019年 | 53篇 |
2018年 | 42篇 |
2017年 | 63篇 |
2016年 | 53篇 |
2015年 | 60篇 |
2014年 | 74篇 |
2013年 | 57篇 |
2012年 | 84篇 |
2011年 | 89篇 |
2010年 | 68篇 |
2009年 | 64篇 |
2008年 | 84篇 |
2007年 | 69篇 |
2006年 | 57篇 |
2005年 | 43篇 |
2004年 | 43篇 |
2003年 | 34篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 17篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有1340条查询结果,搜索用时 15 毫秒
41.
42.
43.
《Food Control》2015
Tree nut allergies are considered an important health issue in developed countries. To comply with the regulations on food labeling, reliable allergen detection methods are required. In this work we isolated almond-specific recombinant antibody fragments (scFv) from a commercial phage display library bypassing the use of live animals, hence being consistent with the latest policies on animal welfare. To this end an iterative selection procedure employing the Tomlinson I phage display library and a crude almond protein extract was carried out. Two different almond-specific scFv (named PD1F6 and PD2C9) were isolated after two rounds of biopanning, and an indirect phage ELISA was implemented to detect the presence of almond protein in foodstuffs. The isolated scFvs demonstrated to be highly specific and allowed detection of 40 ng mL−1 and 100 ng mL−1 of raw and roasted almond protein, respectively. The practical detection limit of the assay in almond spiked food products was 0.1 mg g−1 (110–120 ppm). The developed indirect phage ELISA was validated by analysis of 92 commercial food products, showing good correlation with the results obtained by a previously developed real-time PCR method for the detection of almond in foodstuffs. The selected phage clones can be affinity maturated to improve their sensitivity and genetically engineered to be employed in different assay formats. 相似文献
44.
Subunit‐Specific Labeling of Ubiquitin Chains by Using Sortase: Insights into the Selectivity of Deubiquitinases 下载免费PDF全文
Sean O. Crowe Dr. Grace H. Pham Jacob C. Ziegler Kirandeep K. Deol Dr. Robert G. Guenette Prof. Ying Ge Prof. Eric R. Strieter 《Chembiochem : a European journal of chemical biology》2016,17(16):1525-1531
Information embedded in different ubiquitin chains is transduced by proteins with ubiquitin‐binding domains (UBDs) and erased by a set of hydrolytic enzymes referred to as deubiquitinases (DUBs). Understanding the selectivity of UBDs and DUBs is necessary for decoding the functions of different ubiquitin chains. Critical to these efforts is the access to chemically defined ubiquitin chains bearing site‐specific fluorescent labels. One approach toward constructing such molecules involves peptide ligation by sortase (SrtA), a bacterial transpeptidase responsible for covalently attaching cell surface proteins to the cell wall. Here, we demonstrate the utility of SrtA in modifying individual subunits of ubiquitin chains. Using ubiquitin derivatives in which an N‐terminal glycine is unveiled after protease‐mediated digestion, we synthesized ubiquitin dimers, trimers, and tetramers with different isopeptide linkages. SrtA was then used in combination with fluorescent depsipeptide substrates to effect the modification of each subunit in a chain. By constructing branched ubiquitin chains with individual subunits tagged with a fluorophore, we provide evidence that the ubiquitin‐specific protease USP15 prefers ubiquitin trimers but has little preference for a particular isopeptide linkage. Our results emphasize the importance of subunit‐specific labeling of ubiquitin chains when studying how DUBs process these chains. 相似文献
45.
Prof. Aaron R. Van Dyke Lily S. Etemad Michael J. Vessicchio George A. Naclerio Victoria Jedson 《Chembiochem : a European journal of chemical biology》2016,17(17):1602-1605
A strategy for labeling native enzymes in a manner that preserves their activity is reported: capture–tag–release (CTR). Key to this approach is the small molecule CTR probe that contains an enzyme inhibitor, benzophenone crosslinker, and aryl phosphine ester. After UV‐derived capture of the enzyme, addition of an azide‐containing tag triggers a Staudinger ligation that labels the enzyme. A further consequence of the Staudinger ligation is fragmentation of the CTR probe, thus releasing the inhibitor and restoring enzymatic activity. As a proof‐of‐principle, the CTR strategy was applied to the hydrolase β‐galactosidase. The enzyme was efficiently labeled with biotin, and the kinetic data for the biotinylated enzyme were comparable to those for unlabeled β‐galactosidase. The CTR probe exhibits excellent targeting specificity, as it selectively labeled β‐galactosidase in a complex protein mixture. 相似文献
46.
钙是人体所必需的元素之一,参与众多的生命生理调控,准确测量生物体的钙吸收率,对于合理补钙和预防钙代谢疾病具有重要意义。本研究采用41 Ca标记SD大鼠体内钙库,利用加速器质谱(AMS)法测量长寿命放射性核素41 Ca灵敏度高的特点,开展对大鼠钙吸收率的准确测定。结果表明:大鼠每100g体重每天摄入28 mg碳酸钙、28 mg柠檬酸钙、10 mg碳酸钙的表观吸收率分别为(67.57±2.79)%、(65.21±2.96)%、(87.50±1.10)%,净吸收率分别为(73.19±3.60)%、(71.47±4.01)%、(92.74±1.81)%。该方法可以得出钙的真实吸收率,且不受所评价的钙剂中钙的化学形式和种类的影响,进一步拓展了同位素评价钙吸收率的应用领域,可为建立适宜于我国人民的钙参考摄入量标准提供实验依据。 相似文献
47.
基于快速区域标签运算的目标跟踪算法 总被引:1,自引:1,他引:0
应用于目标跟踪中的快速标签算法,以二值化后的图像中不多于254个连通区域为条件,通过对所有目标的目标特征统计,及与真实目标的特征匹配,实现系统的实时、准确的目标跟踪。 相似文献
48.
49.
50.
Fatemeh Habibpourmehraban Yunqi Wu Jemma X. Wu Sara Hamzelou Farhad Masoomi-Aladizgeh Karthik Shantharam Kamath Ardeshir Amirkhani Brian J. Atwell Paul A. Haynes 《International journal of molecular sciences》2022,23(3)
Rice crops are often subject to multiple abiotic stresses simultaneously in both natural and cultivated environments, resulting in yield reductions beyond those expected from single stress. We report physiological changes after a 4 day exposure to combined drought, salt and extreme temperature treatments, following a 2 day salinity pre-treatment in two rice genotypes—Nipponbare (a paddy rice) and IAC1131 (an upland landrace). Stomata closed after two days of combined stresses, causing intercellular CO2 concentrations and assimilation rates to diminish rapidly. Abscisic acid (ABA) levels increased at least five-fold but did not differ significantly between the genotypes. Tandem Mass Tag isotopic labelling quantitative proteomics revealed 6215 reproducibly identified proteins in mature leaves across the two genotypes and three time points (0, 2 and 4 days of stress). Of these, 987 were differentially expressed due to stress (cf. control plants), including 41 proteins that changed significantly in abundance in all stressed plants. Heat shock proteins, late embryogenesis abundant proteins and photosynthesis-related proteins were consistently responsive to stress in both Nipponbare and IAC1131. Remarkably, even after 2 days of stress there were almost six times fewer proteins differentially expressed in IAC1131 than Nipponbare. This contrast in the translational response to multiple stresses is consistent with the known tolerance of IAC1131 to dryland conditions. 相似文献