全文获取类型
收费全文 | 1498篇 |
免费 | 90篇 |
国内免费 | 60篇 |
专业分类
电工技术 | 33篇 |
综合类 | 34篇 |
化学工业 | 570篇 |
金属工艺 | 85篇 |
机械仪表 | 26篇 |
建筑科学 | 123篇 |
矿业工程 | 15篇 |
能源动力 | 23篇 |
轻工业 | 94篇 |
水利工程 | 4篇 |
石油天然气 | 44篇 |
武器工业 | 2篇 |
无线电 | 64篇 |
一般工业技术 | 291篇 |
冶金工业 | 27篇 |
原子能技术 | 18篇 |
自动化技术 | 195篇 |
出版年
2024年 | 9篇 |
2023年 | 112篇 |
2022年 | 379篇 |
2021年 | 472篇 |
2020年 | 163篇 |
2019年 | 28篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 17篇 |
2014年 | 27篇 |
2013年 | 22篇 |
2012年 | 42篇 |
2011年 | 42篇 |
2010年 | 19篇 |
2009年 | 43篇 |
2008年 | 37篇 |
2007年 | 44篇 |
2006年 | 31篇 |
2005年 | 11篇 |
2004年 | 22篇 |
2003年 | 19篇 |
2002年 | 17篇 |
2001年 | 14篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有1648条查询结果,搜索用时 13 毫秒
41.
近年来,渤海油田针对渤海湾盆地渤中凹陷西南部深层太古宇变质岩潜山开展了勘探实践,成功发现渤中19-6大型整装凝析气田。目前,对于该气田优质裂缝型储集体发育控制因素认识不清,阻碍了下一步勘探进展。综合利用钻井岩芯、岩石薄片和成像测井等资料,对渤中19-6变质岩潜山裂缝型储层的形成机制进行研究。结果表明:渤中19-6构造带深层潜山储层是由太古宇变质花岗岩潜山为主体组成的立体网状裂缝型储集系统,上部形成风化裂缝带、内幕形成网状裂缝带的双层储层结构。上部风化裂缝带具有孔隙型和裂缝型的双重特性,下部内幕裂缝带以裂缝型储层为主。潜山风化裂缝带和内幕裂缝带储层的形成与分布均受控于3期构造活动的叠加作用,印支期以来是潜山裂缝的主要发育时期。由此建立了研究区太古宇潜山变质岩“优势岩性—多期裂缝”的成储模式。 相似文献
42.
Soragia Athina Gkazi Emma Gravett Carla Bautista Jack Bartram Sara Ghorashian Stuart Paul Adams 《International journal of molecular sciences》2022,23(14)
Chimeric antigen receptor (CAR) T cell therapy is an innovative immunotherapy for treating cancers in both children and adults with proven utility in numerous clinical trials. Significantly, some CAR T cell therapies have now been approved by relevant national regulatory bodies across numerous countries for clinical therapeutic use outside of clinical trials. One such recently licensed product is tisagenlecleucel, a CAR T therapy approved for the treatment of B-cell acute lymphoblastic leukemia (B-ALL) using autologous T cells from the patient. The genetically engineered T cells target a protein called CD19, common to B cells, through a CAR incorporating a 4-1BB costimulatory domain to improve response. Since tisagenlecleucel is now a standard of care treatment for B-ALL, it is clinically essential to be able to accurately monitor these CAR T cells in patients. Assessment of the copy number variant (CNV) of the CAR T cell products allows this within a clinically acceptable timeframe for optimal patient benefit. However, no standardized method with high reproducibility and efficiency has been described within a routine clinical laboratory setting. Here, we demonstrated a novel digital droplet PCR (ddPCR)-based methodology for the study of CNV (ddPCR-CNV) in 4-1BB CD19-specific CAR T cells with universal applicability across clinical diagnostic laboratories. 相似文献
43.
44.
Martina Fabris Fabio Del Ben Emanuela Sozio Antonio Paolo Beltrami Adriana Cif Giacomo Bertolino Federica Caponnetto Marco Cotrufo Carlo Tascini Francesco Curcio 《International journal of molecular sciences》2022,23(9)
The main aim of this study was to identify the most relevant cytokines which, when assessed in the earliest stages from hospital admission, may help to select COVID-19 patients with worse prognosis. A retrospective observational study was conducted in 415 COVID-19 patients (272 males; mean age 68 ± 14 years) hospitalized between May 2020 and March 2021. Within the first 72 h from hospital admission, patients were tested for a large panel of biomarkers, including C-reactive protein (CRP), Mid-regional proadrenomedullin (MR-proADM), Interferon-γ, interleukin 6 (IL-6), IL-1β, IL-8, IL-10, soluble IL2-receptor-α (sIL2Rα), IP10 and TNFα. Extensive statistical analyses were performed (correlations, t-tests, ranking tests and tree modeling). The mortality rate was 65/415 (15.7%) and a negative outcome (death and/or orotracheal intubation) affected 98/415 (23.6%) of cases. Univariate tests showed the majority of biomarkers increased in severe patients, but ranking tests helped to select the best variables to put on decisional tree modeling which identified IL-6 as the first dichotomic marker with a cut-off of 114 pg/mL. Then, a good synergy was found between IL-10, MR-proADM, sIL2Rα, IP10 and CRP in increasing the predictive value in classifying patients at risk or not for a negative outcome. In conclusion, beside IL-6, a panel of other cytokines representing the degree of immunoparalysis and the anti-inflammatory response (IP10, sIL2Rα and IL-10) showed synergic role when combined to biomarkers of systemic inflammation and endothelial dysfunction (CRP, MR-proADM) and may also better explain disease pathogenesis and suggests targeted intervention. 相似文献
45.
Tom Schreiner Lisa Allnoch Georg Beythien Katarzyna Marek Kathrin Becker Dirk Schaudien Stephanie Stanelle-Bertram Berfin Schaumburg Nancy Mounogou Kouassi Sebastian Beck Martin Zickler Gülsah Gabriel Wolfgang Baumgrtner Federico Armando Malgorzata Ciurkiewicz 《International journal of molecular sciences》2022,23(9)
Similar to many other respiratory viruses, SARS-CoV-2 targets the ciliated cells of the respiratory epithelium and compromises mucociliary clearance, thereby facilitating spread to the lungs and paving the way for secondary infections. A detailed understanding of mechanism involved in ciliary loss and subsequent regeneration is crucial to assess the possible long-term consequences of COVID-19. The aim of this study was to characterize the sequence of histological and ultrastructural changes observed in the ciliated epithelium during and after SARS-CoV-2 infection in the golden Syrian hamster model. We show that acute infection induces a severe, transient loss of cilia, which is, at least in part, caused by cilia internalization. Internalized cilia colocalize with membrane invaginations, facilitating virus entry into the cell. Infection also results in a progressive decline in cells expressing the regulator of ciliogenesis FOXJ1, which persists beyond virus clearance and the termination of inflammatory changes. Ciliary loss triggers the mobilization of p73+ and CK14+ basal cells, which ceases after regeneration of the cilia. Although ciliation is restored after two weeks despite the lack of FOXJ1, an increased frequency of cilia with ultrastructural alterations indicative of secondary ciliary dyskinesia is observed. In summary, the work provides new insights into SARS-CoV-2 pathogenesis and expands our understanding of virally induced damage to defense mechanisms in the conducting airways. 相似文献
46.
Manuel Serrano Gerard Espinosa Antonio Serrano Ricard Cervera 《International journal of molecular sciences》2022,23(9)
High prevalence of both criteria and extra-criteria antiphospholipid antibodies (aPL) has been reported in COVID-19 patients. However, the differences in aPL prevalence decreased when an age-matched control group was included. The association of aPL with thrombotic events in COVID-19 is very heterogeneous. This could be influenced by the fact that most of the studies carried out were conducted on small populations enriched with elderly patients in which aPL was measured only at a single point and they were performed with non-standardized assays. The few studies that confirmed aPL in a second measurement showed that aPL levels hardly changed, with the exception of the lupus anticoagulant that commonly reduced. COVID-19 coagulopathy is an aPL-independent phenomenon closely associated with the onset of the disease. Thrombosis occurs later in patients with aPL presence, which is likely an additional prothrombotic factor. B2-glycoprotein deficiency (mainly aPL antigen caused both by low production and consumption) is very common during the SARS-CoV2 infection and has been associated with a greater predisposition to COVID-19 complications. This could be a new prothrombotic mechanism that may be caused by the blockage of its physiological functions, the anticoagulant state being the most important. 相似文献
47.
48.
49.
Xin Min Minghao FangZhaohui Huang Yan’gai LiuChao Tang Tingting QianXiaowen Wu 《Ceramics International》2014
Nitrided LaMgAl11O19 phosphors were prepared by a two-step method involving synthesis at 1550 °C for 4 h, trituration, and firing at 1650 °C for 5 h under a nitrogen atmosphere. Nitrogen was doped into LaMgAl11O19 and bonded with aluminium atoms. The nitrided LaMgAl11O19 phosphors showed plate-like morphology with a rough surface and exhibited strong blue emission at 442 nm and 450 nm, which may be attributed to the energy transition between defect levels. A weak emission band at 590 nm was ascribed to the transition between the VAl acceptor and the valence band, which was excited at 254 nm. 相似文献
50.
Ziyad R. Alashhab Mohammed Anbar Manmeet Mahinderjit Singh Yu-Beng Leau Zaher Ali Al-Sai Sami Abu Alhayja’a 《电子科技学刊:英文版》2021,19(1):25-40
In light of the coronavirus disease 2019 (COVID-19) outbreak caused by the novel coronavirus, companies and institutions have instructed their employees to work from home as a precautionary measure to reduce the risk of contagion. Employees, however, have been exposed to different security risks because of working from home. Moreover, the rapid global spread of COVID-19 has increased the volume of data generated from various sources. Working from home depends mainly on cloud computing (CC) applications that help employees to efficiently accomplish their tasks. The cloud computing environment (CCE) is an unsung hero in the COVID-19 pandemic crisis. It consists of the fast-paced practices for services that reflect the trend of rapidly deployable applications for maintaining data. Despite the increase in the use of CC applications, there is an ongoing research challenge in the domains of CCE concerning data, guaranteeing security, and the availability of CC applications. This paper, to the best of our knowledge, is the first paper that thoroughly explains the impact of the COVID-19 pandemic on CCE. Additionally, this paper also highlights the security risks of working from home during the COVID-19 pandemic. 相似文献