全文获取类型
收费全文 | 24994篇 |
免费 | 1383篇 |
国内免费 | 36篇 |
专业分类
电工技术 | 164篇 |
综合类 | 27篇 |
化学工业 | 5569篇 |
金属工艺 | 501篇 |
机械仪表 | 459篇 |
建筑科学 | 898篇 |
矿业工程 | 46篇 |
能源动力 | 918篇 |
轻工业 | 4645篇 |
水利工程 | 231篇 |
石油天然气 | 136篇 |
武器工业 | 2篇 |
无线电 | 1205篇 |
一般工业技术 | 3712篇 |
冶金工业 | 4059篇 |
原子能技术 | 188篇 |
自动化技术 | 3653篇 |
出版年
2023年 | 191篇 |
2022年 | 192篇 |
2021年 | 739篇 |
2020年 | 511篇 |
2019年 | 621篇 |
2018年 | 738篇 |
2017年 | 770篇 |
2016年 | 834篇 |
2015年 | 720篇 |
2014年 | 968篇 |
2013年 | 1712篇 |
2012年 | 1429篇 |
2011年 | 1836篇 |
2010年 | 1352篇 |
2009年 | 1361篇 |
2008年 | 1238篇 |
2007年 | 1040篇 |
2006年 | 915篇 |
2005年 | 774篇 |
2004年 | 700篇 |
2003年 | 624篇 |
2002年 | 552篇 |
2001年 | 354篇 |
2000年 | 319篇 |
1999年 | 351篇 |
1998年 | 1373篇 |
1997年 | 887篇 |
1996年 | 636篇 |
1995年 | 374篇 |
1994年 | 330篇 |
1993年 | 323篇 |
1992年 | 126篇 |
1991年 | 118篇 |
1990年 | 88篇 |
1989年 | 113篇 |
1988年 | 89篇 |
1987年 | 85篇 |
1986年 | 66篇 |
1985年 | 106篇 |
1984年 | 70篇 |
1983年 | 53篇 |
1982年 | 55篇 |
1981年 | 59篇 |
1980年 | 63篇 |
1979年 | 36篇 |
1978年 | 30篇 |
1977年 | 95篇 |
1976年 | 188篇 |
1975年 | 33篇 |
1973年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
11.
Aguayo-Canela Francisco José Alaiz-Moretón Héctor García-Ordás María Teresa Benítez-Andrades José Alberto Benavides Carmen García-Rodríguez Isaías 《The Journal of supercomputing》2021,77(11):13046-13068
The Journal of Supercomputing - The increasing number of connected devices and the complexity of Internet of Things (IoT) ecosystems are demanding new architectures for managing and securing these... 相似文献
12.
Paola Leonor Quan Marina Sabat-Bresc Yanru Guo Margarita Martín Gabriel Gastaminza 《International journal of molecular sciences》2021,22(9)
Recent research on mast cell biology has turned its focus on MRGPRX2, a new member of the Mas-related G protein-coupled subfamily of receptors (Mrgprs), originally described in nociceptive neurons of the dorsal root ganglia. MRGPRX2, a member of this group, is present not only in neurons but also in mast cells (MCs), specifically, and potentially in other cells of the immune system, such as basophils and eosinophils. As emerging new functions for this receptor are studied, a variety of both natural and pharmacologic ligands are being uncovered, linked to the ability to induce receptor-mediated MC activation and degranulation. The diversity of these ligands, characterized in their human, mice, or rat homologues, seems to match that of the receptor’s interactions. Natural ligands include host defense peptides, basic molecules, and key neuropeptides such as substance P and vasointestinal peptide (known for their role in the transmission of pain and itch) as well as eosinophil granule-derived proteins. Exogenous ligands include MC secretagogues such as compound 48/80 and mastoparan, a component of bee wasp venom, and several peptidergic drugs, among which are members of the quinolone family, neuromuscular blocking agents, morphine, and vancomycin. These discoveries shed light on its capacity as a multifaceted participant in naturally occurring responses within immunity and neural stimulus perception, as in responses at the center of immune pathology. In host defense, the mice Mrgprb2 has been proven to aid mast cells in the detection of peptidic molecules from bacteria and in the release of peptides with antimicrobial activities and other immune mediators. There are several potential actions described for it in tissue homeostasis and repair. In the realm of pathologic response, there is evidence to suggest that this receptor is also involved in chronic inflammation. Furthermore, MRGPRX2 has been linked to the pathophysiology of non-IgE-mediated immediate hypersensitivity drug reactions. Different studies have shown its possible role in other allergic diseases as well, such as asthma, atopic dermatitis, contact dermatitis, and chronic spontaneous urticaria. In this review, we sought to cover its function in physiologic processes and responses, as well as in allergic and nonallergic immune disease. 相似文献
13.
14.
Jan Rinkel Prof. Dr. Jeroen S. Dickschat 《Chembiochem : a European journal of chemical biology》2020,21(6):807-810
Isotopic labeling experiments performed with a newly identified bacterial trichoacorenol synthase established a 1,5-hydride shift occurring in the cyclization mechanism. During EI-MS analysis, major fragments of the sesquiterpenoid were shown to arise via cryptic hydrogen movements. Therefore, the interpretation of earlier results regarding the cyclization mechanism obtained by feeding experiments in Trichoderma is revised. 相似文献
15.
Rosa Vera Oladis T. de Rincón Jesús Ramirez Bárbara Valverde Andrés Díaz-Gómez Rodrigo Sánchez-González 《工业材料与腐蚀》2020,71(7):1125-1137
In this study, the behavior of carbon steel and galvanized steel in nontropical coastal marine environments was evaluated. Evaluation was carried out with specimens with dimensions of 10 cm × 10 cm × 0.3 cm. These specimens were exposed to four testing stations (Iquique, Mejillones, Los Vilos, and San Vicente), where racks were installed both at ground level (ground), as well as in the upper zone of electrical transmission towers (tower). In each station, 24 specimens of A36 carbon steel and galvanized steel were placed (12 each). The corrosivity of the environment was measured using the ISO 9223, 9225, and 9226 standards. The specimens were evaluated on-site, monthly, through visual inspection and photographic record. Once withdrawn, the corrosion rate was determined and the corrosion products were analyzed through Raman and Fourier-transform infrared. The results show that, in all cases, the corrosion rate is greater in the tower than on the ground. However, even though the Los Vilos station is located farther from the sea (3,500 vs. ≈500 m), the corrosion rate of steel in the tower is the highest. This is caused by the generation of HCl from the transformation of lepidocrocite into goethite, in the presence of low chloride content, which acidifies the steel/corrosion product interface. In the case of galvanized steel, the corrosion rate is a function of the chloride content in the atmosphere, obtaining an excellent correlation between both parameters. 相似文献
16.
Neural Processing Letters - The fuzzy time series modeling techniques proposed in this study are based on a fuzzy inference method in which the fuzzy output is either a so-called pliant or quasi... 相似文献
17.
Gerardo Valadez Huerta Johanan Álvarez Jordán Michael Dragon Keno Leites Stephan Kabelac 《International Journal of Hydrogen Energy》2018,43(34):16684-16693
Solid oxide fuel cell (SOFC) systems with anode off-gas recirculation (AGR) and diesel pre-reforming are advantageous because they can operate with the current fuel infrastructure. In the SchIBZ-project, the prototype of such a SOFC system for maritime applications has already been commissioned. In this first paper, we model the system devices to conduct an exergy analysis of this real SOFC plant and validate them with experimental values from experiments in laboratory scale. The results of our simulation agree well with the experimental values. The calculations with the validated results may be closer to the real thermodynamic behavior of such system components than previous literature. 相似文献
18.
This paper reports an investigation into new connection types and their behaviors determined using full-scale experiments. T-shaped connections were created using the IPE standard profile. The aim of this study was to analyze the influence of T connections based on the IPE standard profile, height of beam to height of T-stub joint (H) of T-stub joints, and lengths (X) of T-stub joints on the behavior of steel connections, in order to provide the necessary data for improving Eurocode 3 and enable efficient use of residue IPE standard profiles and back to the consumption cycle. While the moment resistance values increased with an increase in H from Hmin to Hmax in model groups with X of 126 mm, and the energy dissipation increased with an increase in H from Hmin to Hmax and also with an increase in the lengths (X) of T-stub joints from 54 to 126 mm. 相似文献
19.
Sucasas Victor Mantas Georgios Althunibat Saud Ortega José-Fernán Martínez 《Mobile Networks and Applications》2020,25(1):151-152
Mobile Networks and Applications - 相似文献
20.