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排序方式: 共有732条查询结果,搜索用时 15 毫秒
561.
562.
Luidmila Yakimova Aisylu Kunafina Olga Mostovaya Pavel Padnya Timur Mukhametzyanov Alexandra Voloshina Konstantin Petrov Artur Boldyrev Ivan Stoikov 《International journal of molecular sciences》2022,23(17)
The therapeutic application of serum albumin is determined by the relative content of the monomeric form compared to dimers, tetramers, hexamers, etc. In this paper, we propose and develop an approach to synthesize the cone stereoisomer of p-tert-butylthiacalix[4]arene with sulfobetaine fragments stabilization of monomeric bovine serum albumin and preventing aggregation. Spectral methods (UV-vis, CD, fluorescent spectroscopy, and dynamic light scattering) established the influence of the synthesized compounds on the content of monomeric and aggregated forms of BSA even without the formation of stable thiacalixarene/protein associates. The effect of thiacalixarenes on the efficiency of protein binding with the antibiotic ciprofloxacin was shown by fluorescence spectroscopy. The binding constant increases in the presence of the macrocycles, likely due to the stabilization of monomeric forms of BSA. Our study clearly shows the potential of this macrocycle design as a platform for the development of the fundamentally new approaches for preventing aggregation. 相似文献
563.
Patrícia Matos Antnio Paranhos Maria Teresa Batista Artur Figueirinha 《International journal of molecular sciences》2022,23(21)
Overexpression of melanin contributes to darkening of plant and fruit tissues and skin hyperpigmentation, leading to melasma or age spots. Although melanin biosynthesis is complex and involves several steps, a single enzyme known as tyrosinase is key to regulating this process. The melanogenesis pathway is initiated by oxidation of the starting material l-tyrosine (or l-DOPA) to dopaquinone by tyrosinase; the resulting quinone then serves as a substrate for subsequent steps that eventually lead to production of melanin. Medicinal plants are considered a good source of tyrosinase inhibitors. This study investigated the tyrosinase inhibitory activity of A. mollis leaf extracts and their phytochemicals. Significant activity was verified in the ethanol extract –EEt (IC50 = 1.21 µg/mL). Additionally, a kinetic study showed that this tyrosinase inhibition occurs by DIBOA (2,4-dihydroxy-1,4-benzoxazin-3-one) and verbascoside contribution through a non-competitive reaction mechanism. A synergistic effect on tyrosinase inhibition was observed in the binary combination of the compounds. In conclusion, both EEt and a mixture of two of its phytochemicals can be effective tyrosinase inhibitors and can be used as a bleaching agent for cosmetic formulations in the future. 相似文献
564.
Dawid Lazewski Malgorzata Kucinska Edward Potapskiy Joanna Kuzminska Artur Tezyk Lukasz Popenda Stefan Jurga Anna Teubert Zofia Gdaniec Jacek Kujawski Katarzyna Grzyb Tomasz Pedzinski Marek Murias Marcin Wierzchowski 《International journal of molecular sciences》2022,23(17)
This work presents the synthesis and characterization of metal-free, zinc (II), and cobalt (II) porphyrins substituted with short PEG chains. The synthesized compounds were characterized by UV-Vis, 1H and 13C NMR spectroscopy, and MALDI-TOF mass spectrometry. The origin of the absorption bands for tested compounds in the UV-Vis range was determined using a computational model based on the electron density functional theory (DFT) and its time-dependent variant (TD-DFT). The photosensitizing activity was evaluated by measuring the ability to generate singlet oxygen (ΦΔ), which reached values up to 0.54. The photodynamic activity was tested using bladder (5637), prostate (LNCaP), and melanoma (A375) cancer cell lines. In vitro experiments clearly showed the structure–activity relationship regarding types of substituents, their positions in the phenyl ring, and the variety of central metal ions on the porphyrin core. Notably, the metal-free derivative 3 and its zinc derivative 6 exerted strong cytotoxic activity toward 5637 cells, with IC50 values of 8 and 15 nM, respectively. None of the tested compounds induced a cytotoxic effect without irradiation. In conclusion, these results highlight the potential value of the tested compounds for PDT application. 相似文献
565.
Magorzata Sobociska Jakub Fichna Artur Giedo Piotr Skowron Elbieta Kamysz 《International journal of molecular sciences》2022,23(22)
Pharmacotherapy for inflammatory bowel disease (IBD) is difficult, and some patients do not respond to currently available treatments. Therefore, the discovery of novel anti-IBD agents is imperative. Our aim was the synthesis of lipidated analogs of sialorphin and the in vitro characterization of their effect on the degradation of Met-enkephalin by neutral endopeptidase (NEP). We also investigated in vivo whether the most active inhibitor (peptide VIII) selected in the in vitro studies could be a potential candidate for the treatment of colitis. Peptides were synthesized by the solid-phase method. Molecular modeling technique was used to explain the effect of fatty acid chain length in sialorphin analogs on the ligand–enzyme interactions. The anti-inflammatory effect was evaluated in the dextran sulphate sodium (DSS)-induced model of colitis in mice. Peptide VIII containing stearic acid turned out to be in vitro the strongest inhibitor of NEP. We have also shown that the length of the chain of stearic acid fits the size of the grove of NEP. Peptides VII and VIII exhibited in vivo similar anti-inflammatory activity. Our results suggest that lipidation of sialorphin molecule is a promising direction in the search for NEP inhibitors that protect enkephalins. 相似文献
566.
Hinkel Georg Garcia-Dominguez Antonio Schne Ren Boronat Artur Tisi Massimo Le Calvar Tho Jouault Frederic Marton Jzsef Nyri Tams Antal Jnos Benjamin Elekes Mrton Szrnyas Gbor 《Software and Systems Modeling》2022,21(2):755-804
Software and Systems Modeling - To cope with the increased complexity of systems, models are used to capture what is considered the essence of a system. Such models are typically represented as a... 相似文献
567.
Gi Hyun Lim Nuno Lau Eurico Pedrosa Filipe Amaral Artur Pereira José Luís Azevedo 《Advanced Robotics》2019,33(13):636-646
Object manipulation tasks such as picking up, carrying and placing should be executed based on the information of objects which are provided by the perception system. A precise and efficient pose estimation system has been developed to address the requirements and to achieve the objectives for autonomous packaging, specifically picking up of stacked non-rigid objects. For fine pose estimation, a drawing pin shaped kernel and pinhole filtering methods are used on the roughly estimated pose of objects. The system has been applied in a realistic industrial environment as a challenging scenario for the Challenge 2 – Shop Floor Logistics and Manipulation on a mobile manipulator in the context of the European Robotics Challenges (EuRoC) project. 相似文献
568.
Dias Jnior Ananias Francisco Andrade Carlos Rogrio Lana Artur Queiroz da Silva lison Moreira Brito Jos Otvio Milan Marcos 《Holz als Roh- und Werkstoff》2021,79(4):1017-1026
European Journal of Wood and Wood Products - Charcoal is a widely used barbecue product that comes into direct and indirect contact with the foods ingested. Thus, it must have adequate technical... 相似文献
569.
Artur Bobrowski Dariusz Dro?yński Beata Grabowska Karolina Kaczmarska ?aneta Kurleto–Kozio? Marcin Brzeziński 《中国铸造》2018,15(2):145-151
This paper presents results of thermoanalytical and structural research on phenolic binder used in foundry for the preparation of moulding sand. The binder has been prepared based on resole type phenolic resin with the addition of ester hardener. The aim of the study was to determine the structural changes taking place in the phenolic binder under the influence of temperature. Results show that in the investigated range of temperatures, phenolic binder exhibits three exothermic thermal effects accompanying the decomposition process. The test results using the Diffuse Reflectance Infrared Fourier Transform Spectroscopy(DRIFTS) technique show that the addition of a hardener stabilizes the binder structure within methylene bridges. The reduction in the reaction rate observed in the DTA curve at about 330 °C can be associated with the formation of gaseous products by decomposition of the binder or, as suggested by the literature data, the formation of triple bonds and CN-HCN groups. 相似文献
570.
Carmen Martín-Sierra Simone Colombo Ricardo Martins Paula Laranjeira Tânia Melo Ana Margarida Abrantes Rui Caetano Oliveira José Guilherme Tralhão Maria Filomena Botelho Emanuel Furtado Pedro Domingues M. Rosario Domingues Artur Paiva 《Lipids》2020,55(2):185-191
Hepatocellular carcinoma and cholangiocarcinoma are the most common primary malignant liver tumors. Since the liver plays a key role in lipid metabolism, the study of serum phospholipid (PL) profiles may provide a better understanding of alterations in hepatic lipid metabolism. In this study, we used a high-resolution HILIC-LC–MS lipidomic approach to establish the serum phospholipidome profile of patients with liver cancer before (T0) and after tumor resection (T1) and a control group (CT) of healthy individuals. After the analysis of PL profiles, we observed that the phospholipidome of patients with liver cancer was significantly modified after the tumor resection procedure. We observed an upregulation of some phosphatidylcholine (PtdCho) species, namely, PtdCho(36:6), PtdCho(42:6), PtdCho(38:5), PtdCho(36:5), PtdCho(38:6) and choline plasmalogens (PlsCho), and/or 1-O-alkyl-2-acyl-glycerophosphocholine (PakCho) in patients with liver cancer at T0 compared to the CT group, and a downregulation after tumor resection (T1) when compared to T0. These results show that LC–MS can detect different serum PL profiles in patients with liver cancer, before and after tumor resection, by defining a specific PL fingerprint that was used to determine the effect of tumor and tumor resection on lipid metabolism. 相似文献