全文获取类型
| 收费全文 | 1574篇 |
| 免费 | 23篇 |
| 国内免费 | 10篇 |
专业分类
| 电工技术 | 30篇 |
| 综合类 | 1篇 |
| 化学工业 | 389篇 |
| 金属工艺 | 28篇 |
| 机械仪表 | 52篇 |
| 建筑科学 | 29篇 |
| 矿业工程 | 1篇 |
| 能源动力 | 114篇 |
| 轻工业 | 97篇 |
| 水利工程 | 11篇 |
| 石油天然气 | 9篇 |
| 无线电 | 177篇 |
| 一般工业技术 | 379篇 |
| 冶金工业 | 62篇 |
| 原子能技术 | 15篇 |
| 自动化技术 | 213篇 |
出版年
| 2024年 | 44篇 |
| 2023年 | 32篇 |
| 2022年 | 84篇 |
| 2021年 | 76篇 |
| 2020年 | 82篇 |
| 2019年 | 57篇 |
| 2018年 | 88篇 |
| 2017年 | 67篇 |
| 2016年 | 54篇 |
| 2015年 | 39篇 |
| 2014年 | 81篇 |
| 2013年 | 156篇 |
| 2012年 | 75篇 |
| 2011年 | 104篇 |
| 2010年 | 71篇 |
| 2009年 | 79篇 |
| 2008年 | 74篇 |
| 2007年 | 59篇 |
| 2006年 | 42篇 |
| 2005年 | 50篇 |
| 2004年 | 39篇 |
| 2003年 | 15篇 |
| 2002年 | 26篇 |
| 2001年 | 19篇 |
| 2000年 | 11篇 |
| 1999年 | 7篇 |
| 1998年 | 12篇 |
| 1997年 | 12篇 |
| 1996年 | 5篇 |
| 1995年 | 8篇 |
| 1994年 | 11篇 |
| 1993年 | 1篇 |
| 1992年 | 6篇 |
| 1990年 | 2篇 |
| 1989年 | 1篇 |
| 1987年 | 3篇 |
| 1985年 | 3篇 |
| 1984年 | 1篇 |
| 1982年 | 1篇 |
| 1981年 | 3篇 |
| 1979年 | 2篇 |
| 1978年 | 2篇 |
| 1972年 | 1篇 |
| 1967年 | 1篇 |
| 1953年 | 1篇 |
排序方式： 共有1607条查询结果，搜索用时 15 毫秒
51.
52.
Christabelle Rajesh Satish Sagar Ashok Kumar Rathinavel Divya Thomas Chemparathy Xianlu Laura Peng Jen Jen Yeh Michael A. Hollingsworth Prakash Radhakrishnan 《International journal of molecular sciences》2022,23(10)
Elevated levels of Mucin-16 (MUC16) in conjunction with a high expression of truncated O-glycans is implicated in playing crucial roles in the malignancy of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms by which such aberrant glycoforms present on MUC16 itself promote an increased disease burden in PDAC are yet to be elucidated. This study demonstrates that the CRISPR/Cas9-mediated genetic deletion of MUC16 in PDAC cells decreases tumor cell migration. We found that MUC16 enhances tumor malignancy by activating the integrin-linked kinase and focal adhesion kinase (ILK/FAK)-signaling axis. These findings are especially noteworthy in truncated O-glycan (Tn and STn antigen)-expressing PDAC cells. Activation of these oncogenic-signaling pathways resulted in part from interactions between MUC16 and integrin complexes (α4β1), which showed a stronger association with aberrant glycoforms of MUC16. Using a monoclonal antibody to functionally hinder MUC16 significantly reduced the migratory cascades in our model. Together, these findings suggest that truncated O-glycan containing MUC16 exacerbates malignancy in PDAC by activating FAK signaling through specific interactions with α4 and β1 integrin complexes on cancer cell membranes. Targeting these aberrant glycoforms of MUC16 can aid in the development of a novel platform to study and treat metastatic pancreatic cancer. 相似文献
53.
Chih-Chien Hu Selvaraj Rajesh Kumar Truong Thi Tuong Vi Yu-Tzu Huang Dave W. Chen Shingjiang Jessie Lue 《International journal of molecular sciences》2022,23(1)
In the present work, the antimicrobial peptide (AMP) of GL13K was successfully coated onto a polyetheretherketone (PEEK) substrate to investigate its antibacterial activities against Staphylococcus aureus (S. aureus) bacteria. To improve the coating efficiency, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was mixed with a GL13K solution and coated on the PEEK surface for comparison. Both energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) data confirmed 30% greater peptide coating on PEEK/GL13K-EDC than PEEK without EDC treatment. The GL13K graft levels are depicted in the micrograms per square centimeter range. The PEEK/GL13K-EDC sample showed a smoother and lower roughness (Rq of 0.530 µm) than the PEEK/GL13K (0.634 µm) and PEEK (0.697 µm) samples. The surface of the PEEK/GL13K-EDC was more hydrophilic (with a water contact angle of 24°) than the PEEK/GL13K (40°) and pure PEEK (89°) samples. The pure PEEK disc did not exhibit any inhibition zone against S. aureus. After peptide coating, the samples demonstrated significant zones of inhibition: 28 mm and 25 mm for the PEEK/GL13K-EDC and PEEK/GL13K samples, respectively. The bacteria-challenged PEEK sample showed numerous bacteria clusters, whereas PEEK/GL13K contained a little bacteria and PEEK/GL13K-EDC had no bacterial attachment. The results confirm that the GL13K peptide coating was able to induce antibacterial and biofilm-inhibitory effects. To the best of our knowledge, this is the first report of successful GL13K peptide grafting on a PEEK substrate via EDC coupling. The present work illustrates a facile and promising coating technique for a polymeric surface to provide bactericidal activity and biofilm resistance to medical implantable devices. 相似文献
54.
Rajesh Mondal Zeus Saldaa-Ahuactzi Jorge Soria-Bustos Andrew Schultz Jorge A. Yaez-Santos Ygnacio Martínez Laguna María L. Cedillo-Ramírez Jorge A. Girn 《International journal of molecular sciences》2022,23(18)
The attachment of enteropathogenic Escherichia coli (EPEC) to intestinal epithelial cells is facilitated by several adhesins; however, the individual host-cell receptors for pili-mediated adherence have not been fully characterized. In this study, we evaluated the hypothesis that the E. coli common pilus (ECP) tip adhesin protein EcpD mediates attachment of EPEC to several extracellular matrix (ECM) glycoproteins (fibronectin, laminin, collagens I and IV, and mucin). We found that the ΔecpA mutant, which lacks production of the EcpA filament but retains EcpD on the surface, adhered to these glycoproteins below the wild-type levels, while the ΔecpD mutant, which does not display EcpA or EcpD, bound significantly less to these host glycoproteins. In agreement, a purified recombinant EcpD subunit bound significantly more than EcpA to laminin, fibronectin, collagens I and IV, and mucin in a dose-dependent manner. These are compelling data that strongly suggest that ECP-producing EPEC may bind to host ECM glycoproteins and mucins through the tip adhesin protein EcpD. This study highlights the versatility of EPEC to bind to different host proteins and suggests that the interaction of ECP with the host’s ECM glycoproteins may facilitate colonization of the intestinal mucosal epithelium. 相似文献
55.
Jaykumar Patel Deepesh Khandwal Babita Choudhary Dolly Ardeshana Rajesh Kumar Jha Bhakti Tanna Sonam Yadav Avinash Mishra Rajeev K. Varshney Kadambot H. M. Siddique 《International journal of molecular sciences》2022,23(2)
The frequency and severity of extreme climatic conditions such as drought, salinity, cold, and heat are increasing due to climate change. Moreover, in the field, plants are affected by multiple abiotic stresses simultaneously or sequentially. Thus, it is imperative to compare the effects of stress combinations on crop plants relative to individual stresses. This study investigated the differential regulation of physio-biochemical and metabolomics parameters in peanut (Arachis hypogaea L.) under individual (salt, drought, cold, and heat) and combined stress treatments using multivariate correlation analysis. The results showed that combined heat, salt, and drought stress compounds the stress effect of individual stresses. Combined stresses that included heat had the highest electrolyte leakage and lowest relative water content. Lipid peroxidation and chlorophyll contents did not significantly change under combined stresses. Biochemical parameters, such as free amino acids, polyphenol, starch, and sugars, significantly changed under combined stresses compared to individual stresses. Free amino acids increased under combined stresses that included heat; starch, sugars, and polyphenols increased under combined stresses that included drought; proline concentration increased under combined stresses that included salt. Metabolomics data that were obtained under different individual and combined stresses can be used to identify molecular phenotypes that are involved in the acclimation response of plants under changing abiotic stress conditions. Peanut metabolomics identified 160 metabolites, including amino acids, sugars, sugar alcohols, organic acids, fatty acids, sugar acids, and other organic compounds. Pathway enrichment analysis revealed that abiotic stresses significantly affected amino acid, amino sugar, and sugar metabolism. The stress treatments affected the metabolites that were associated with the tricarboxylic acid (TCA) and urea cycles and associated amino acid biosynthesis pathway intermediates. Principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and heatmap analysis identified potential marker metabolites (pinitol, malic acid, and xylopyranose) that were associated with abiotic stress combinations, which could be used in breeding efforts to develop peanut cultivars that are resilient to climate change. The study will also facilitate researchers to explore different stress indicators to identify resistant cultivars for future crop improvement programs. 相似文献
56.
Neetu Rathore Asita Kulshreshtha Rajesh Kumar Shukla Darshan Sharma 《International Journal of Applied Ceramic Technology》2022,19(3):1766-1778
Here, sol–gel derived Fe–TiO2 anatase nanoparticles with varying concentrations of Ti(1–x)FexO2 (x = 0%, 1%, 5%, 10%) were prepared. The structural, morphological, and optical properties of prepared samples were studied. X-ray diffraction (XRD) patterns show the formation of pure anatase phase. The mean crystallite size of Fe–TiO2 decreases with increase in the concentration of Fe. Fourier transform infrared spectroscopy (FTIR) spectra confirmed the presence of Ti–O vibrational band for all the samples. In Raman spectrum, peak broadening and red shifting linked with Eg ∼144 cm–1 divulge the Fe substitution at Ti sites into host lattice structure. Photoluminescence (PL) spectra verified nine peaks related to near band-edge emission and various defect states. The UV–vis diffuse reflectance spectra represent redshift and reduction in the bandgap energy. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations show that the size of the grains decreases with increase in Fe doping concentration. The study shows that Fe-doped TiO2 anatase phase nanoparticles are suitable for photocatalytic activity and solar cell applications. 相似文献
57.
Dr. Anil Karbhari Shinde Dr. Rajesh Kumar Badange Veena Reballi Pramod Kumar Achanta Kumar Bojja Sravanthi Manchineella Nageswara Rao Muddana Ramkumar Subramanian Raghava Choudary Palacharla Vijay Benade Dr. Pradeep Jayarajan Jagadeesh Babu Thentu Bujji Babu Lingavarapu Sivasekhar Yarra Narendra Kagita Mallikarjuna Rao Doguparthi Dr. Abdul Rasheed Mohammed Dr. Ramakrishna Nirogi 《ChemMedChem》2022,17(3):e202100583
A series of chemical optimizations, which was guided by in vitro affinity at histamine H3 receptor (H3R), modulation of lipophilicity, ADME properties and preclinical efficacy resulted in the identification of 1-[2-(1-cyclobutylpiperidin-4-yloxy)-6,7-dihydro-4H-thiazolo[5,4-c]pyridin-5-yl]propan-1-one ( 45 e ) as a potent and selective (Ki=4.0 nM) H3R inverse agonist. Dipsogenia induced by (R)-α-methylhistamine was dose dependently antagonized by 45 e , confirming its functional antagonism at H3R. It is devoid of hERG and phospholipidosis issues. Compound 45 e has adequate oral exposures and favorable half-life in both rats and dogs. It has demonstrated high receptor occupancy (ED80=0.22 mg/kg) and robust efficacy in object recognition task and, dose dependently increased acetylcholine levels in brain. The sub-therapeutic doses of 45 e in combination with donepezil significantly increased acetylcholine levels. The potent affinity, selectivity, in vivo efficacy and drug like properties together with safety, warrant for further development of this molecule for potential treatment of cognitive disorders associated with Alzheimer's disease. 相似文献
58.
Anjali Baudh;Meenakshi Garjola;Rahul Sharma;Sweta Sharma;Rajesh Kumar Upadhyay; 《加拿大化工杂志》2024,102(11):3803-3816
Hydrogen is a potential energy carrier in comparison to conventional fuels due to its high energy content. Methane is an attractive source for ‘on-site’ production of hydrogen by using membrane reformer due to its low cost. However, such reformers are not well studied and high temperature operation of steam methane reforming (SMR) makes the integration with membrane separation difficult. Further, the main product of SMR is CO and H2 in which CO has an inhibition effect on the membrane separation process. Therefore, it is vital to synthesize a low temperature and low CO selective catalyst for a suitable integration with membrane reformer. Nickel-based catalyst is widely used for SMR due to its low cost and high catalytic activity. CeO2 is a favoured support as it mobilizes the lattice oxygen and reduces the coke formation and CO selectivity. Though several studies are reported on CeO2 based support, the effect of CeO2 surface morphology is not studied for SMR. In the current work, Ni/CeO2 of different shapes (nanocube and nanorod) are synthesized. The complete characterization of the support was performed. The effect of support shape, calcination temperature, and reduction temperature on SMR activity is found at different operating temperatures. For each condition conversion, CO, CO2 selectivity, and hydrogen yield are calculated. The results show the CeO2 morphology has a considerable effect on conversion, CO selectivity, and hydrogen yield. It is found that ceria nanocube calcined at 550°C provides better performance at high temperature. 相似文献
59.
We have developed a custom analog CMOS circuit to perform the signal processing for an optical coherence tomography imaging system. The circuit is realized in a 1.5 /spl mu/m low-noise analog CMOS technology. The circuitry extracts the Doppler frequency from the signal and electrically mixes this with the original signal to provide a filtered A-scan. The circuitry was used to produce a two-dimensional image of an onion. 相似文献
60.
ABSTRACT Design optimization of single-winding dual speed and double-winding dual-speed three phase induction motors is attempted. The choice of independent variables and the specification of the performance requirements for these two types of motors are discussed. The formation of an objective function end the various steps involved in the minimization process are explained. It has been shown that comprehensive computer programs can be developed to design optimum dual speed motors of any pole ratio with any stator coil span and winding connection. 相似文献