全文获取类型
收费全文 | 1738篇 |
免费 | 82篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 11篇 |
综合类 | 1篇 |
化学工业 | 352篇 |
金属工艺 | 10篇 |
机械仪表 | 11篇 |
建筑科学 | 81篇 |
矿业工程 | 1篇 |
能源动力 | 24篇 |
轻工业 | 309篇 |
水利工程 | 18篇 |
石油天然气 | 4篇 |
无线电 | 79篇 |
一般工业技术 | 294篇 |
冶金工业 | 444篇 |
原子能技术 | 1篇 |
自动化技术 | 183篇 |
出版年
2023年 | 24篇 |
2022年 | 50篇 |
2021年 | 70篇 |
2020年 | 43篇 |
2019年 | 45篇 |
2018年 | 41篇 |
2017年 | 45篇 |
2016年 | 39篇 |
2015年 | 54篇 |
2014年 | 61篇 |
2013年 | 78篇 |
2012年 | 77篇 |
2011年 | 120篇 |
2010年 | 85篇 |
2009年 | 85篇 |
2008年 | 107篇 |
2007年 | 115篇 |
2006年 | 95篇 |
2005年 | 88篇 |
2004年 | 83篇 |
2003年 | 63篇 |
2002年 | 48篇 |
2001年 | 23篇 |
2000年 | 26篇 |
1999年 | 25篇 |
1998年 | 23篇 |
1997年 | 20篇 |
1996年 | 38篇 |
1995年 | 22篇 |
1994年 | 19篇 |
1993年 | 18篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1823条查询结果,搜索用时 10 毫秒
51.
Mohammed S. Shafae Rebecca M. Dickinson William H. Woodall Jaime A. Camelio 《Quality and Reliability Engineering International》2015,31(5):839-849
The Weibull distribution can be used to effectively model many different failure mechanisms due to its inherent flexibility through the appropriate selection of a shape and a scale parameter. In this paper, we evaluate and compare the performance of three cumulative sum (CUSUM) control charts to monitor Weibull‐distributed time‐between‐event observations. The first two methods are the Weibull CUSUM chart and the exponential CUSUM (ECUSUM) chart. The latter is considered in literature to be robust to the assumption of the exponential distribution when observations have a Weibull distribution. For the third CUSUM chart included in this study, an adjustment in the design of the ECUSUM chart is used to account for the true underlying time‐between‐event distribution. This adjustment allows for the adjusted ECUSUM chart to be directly comparable to the Weibull CUSUM chart. By comparing the zero‐state average run length and average time to signal performance of the three charts, the ECUSUM chart is shown to be much less robust to departures from the exponential distribution than was previously claimed in the literature. We demonstrate the advantages of using one of the other two charts, which show surprisingly similar performance. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
52.
The occurrence of accidents and injuries continues to be a major problem in construction worldwide. Even though accident statistics have been improving in most markets there are significant areas requiring further attention. The extent of integrated working between designers and constructors may be an instrumental factor. A comparison is undertaken of the accident performance of 55 large construction projects in the UK, with varying levels of design/construction integration as represented by procurement path. Although a statistical relationship between high levels of integration and low levels of accidents was weak, a follow‐up interview study provided strong support, suggesting that a lack of significance was related to the unreliability of the statistics available. The interview study also indicated reasons for this link. A key element in improved safety was seen to be better communications and a more positive relationship between designers and constructors. Further research into designing for safety for all procurement paths is recommended. 相似文献
53.
While contemporary urban theories suggest that individuals have transcended their geographical community, evidence suggests that urban residents still feel ‘attached’ to place. In the literature, several socio-demographic characteristics are associated with place attachment. Scholars suggest physical features, such as community ‘greenspace’, may also influence place attachment. Yet research does not consider the relationship between one's objective proximity to greenspace or the objective availability of community greenspace on residents' place attachment. This study employs multi-level models and draws on police incident data, census data, two spatial data sets and survey data from over 4000 residents living across 148 state suburbs in Australia to assess the relationship between greenspace proximity and greenspace availability on place attachment. Our findings indicate that greater proportions and more accessible greenspace may not improve residents' attachment to their local community. 相似文献
54.
Erin Vanessa LaRae Smith Rebecca Maree Dyson Christina M. G. Vanderboor Ousseynou Sarr Jane Anderson Mary J. Berry Timothy R. H. Regnault Lifeng Peng Clint Gray 《International journal of molecular sciences》2022,23(2)
Excess dietary fructose is a major public health concern, yet little is known about its influence on offspring development and later-life disease when consumed in excess during pregnancy. To determine whether increased maternal fructose intake could have long-term consequences on offspring health, we investigated the effects of 10% w/v fructose water intake during preconception and pregnancy in guinea pigs. Female Dunkin Hartley guinea pigs were fed a control diet (CD) or fructose diet (FD; providing 16% of total daily caloric intake) ad libitum 60 days prior to mating and throughout gestation. Dietary interventions ceased at day of delivery. Offspring were culled at day 21 (D21) (weaning) and at 4 months (4 M) (young adult). Fetal exposure to excess maternal fructose intake significantly increased male and female triglycerides at D21 and 4 M and circulating palmitoleic acid and total omega-7 through day 0 (D0) to 4 M. Proteomic and functional analysis of significantly differentially expressed proteins revealed that FD offspring (D21 and 4 M) had significantly increased mitochondrial metabolic activities of β-oxidation, electron transport chain (ETC) and oxidative phosphorylation and reactive oxygen species production compared to the CD offspring. Western blotting analysis of both FD offspring validated the increased protein abundances of mitochondrial ETC complex II and IV, SREBP-1c and FAS, whereas VDAC1 expression was higher at D21 but lower at 4 M. We provide evidence demonstrating offspring programmed hepatic mitochondrial metabolism and de novo lipogenesis following excess maternal fructose exposure. These underlying asymptomatic programmed pathways may lead to a predisposition to metabolic dysfunction later in life. 相似文献
55.
Bimala Malla Agustin Liotta Helena Bros Rebecca Ulshfer Friedemann Paul Anja E. Hauser Raluca Niesner Carmen Infante-Duarte 《International journal of molecular sciences》2022,23(3)
Teriflunomide (TFN) limits relapses in relapsing–remitting multiple sclerosis (RRMS) by reducing lymphocytic proliferation through the inhibition of the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH) and the subsequent modulation of de novo pyrimidine synthesis. Alterations of mitochondrial function as a consequence of oxidative stress have been reported during neuroinflammation. Previously, we showed that TFN prevents alterations of mitochondrial motility caused by oxidative stress in peripheral axons. Here, we aimed to validate TFN effects on mitochondria and neuronal activity in hippocampal brain slices, in which cellular distribution and synaptic circuits are largely preserved. TFN effects on metabolism and neuronal activity were investigated by assessing oxygen partial pressure and local field potential in acute slices. Additionally, we imaged mitochondria in brain slices from the transgenic Thy1-CFP/COX8A)S2Lich/J (mitoCFP) mice using two-photon microscopy. Although TFN could not prevent oxidative stress-related depletion of ATP, it preserved oxygen consumption and neuronal activity in CNS tissue during oxidative stress. Furthermore, TFN prevented mitochondrial shortening and fragmentation of puncta-shaped and network mitochondria during oxidative stress. Regarding motility, TFN accentuated the decrease in mitochondrial displacement and increase in speed observed during oxidative stress. Importantly, these effects were not associated with neuronal viability and did not lead to axonal damage. In conclusion, during conditions of oxidative stress, TFN preserves the functionality of neurons and prevents morphological and motility alterations of mitochondria. 相似文献
56.
Seigo Nagashima Anderson Azevedo Dutra Mayara Pezzini Arantes Rafaela Chiuco Zeni Carolline Konzen Klein Flvia Centenaro de Oliveira Giulia Werner Piper Isadora Drews Brenny Marcos Roberto Curcio Pereira Rebecca Benicio Stocco Ana Paula Camargo Martins Eduardo Morais de Castro Caroline Busatta Vaz de Paula Andra Novaes Moreno Amaral Cleber Machado-Souza Cristina Pellegrino Baena Lucia Noronha 《International journal of molecular sciences》2022,23(3)
Mast cells (MCs) have relevant participation in inflammatory and vascular hyperpermeability events, responsible for the action of the kallikrein–kinin system (KKS), that affect patients inflicted by the severe form of COVID-19. Given a higher number of activated MCs present in COVID-19 patients and their association with vascular hyperpermeability events, we investigated the factors that lead to the activation and degranulation of these cells and their harmful effects on the alveolar septum environment provided by the action of its mediators. Therefore, the pyroptotic processes throughout caspase-1 (CASP-1) and alarmin interleukin-33 (IL-33) secretion were investigated, along with the immunoexpression of angiotensin-converting enzyme 2 (ACE2), bradykinin receptor B1 (B1R) and bradykinin receptor B2 (B2R) on post-mortem lung samples from 24 patients affected by COVID-19. The results were compared to 10 patients affected by H1N1pdm09 and 11 control patients. As a result of the inflammatory processes induced by SARS-CoV-2, the activation by immunoglobulin E (IgE) and degranulation of tryptase, as well as Toluidine Blue metachromatic (TB)-stained MCs of the interstitial and perivascular regions of the same groups were also counted. An increased immunoexpression of the tissue biomarkers CASP-1, IL-33, ACE2, B1R and B2R was observed in the alveolar septum of the COVID-19 patients, associated with a higher density of IgE+ MCs, tryptase+ MCs and TB-stained MCs, in addition to the presence of intra-alveolar edema. These findings suggest the direct correlation of MCs with vascular hyperpermeability, edema and diffuse alveolar damage (DAD) events that affect patients with a severe form of this disease. The role of KKS activation in events involving the exacerbated increase in vascular permeability and its direct link with the conditions that precede intra-alveolar edema, and the consequent DAD, is evidenced. Therapy with drugs that inhibit the activation/degranulation of MCs can prevent the worsening of the prognosis and provide a better outcome for the patient. 相似文献
57.
Isabell Kemker Rebecca C. Feiner Prof. Dr. Kristian M. Müller Prof. Dr. Norbert Sewald 《Chembiochem : a European journal of chemical biology》2020,21(4):496-499
Monomeric RGD peptides show unspecific fluid-phase uptake in cells, whereas multimeric RGD peptides are thought to be internalized by integrin-mediated endocytosis. However, a potential correlation between uptake mechanism and molecular mass has been neglected so far. A dual derivatization of peptide c(RGDw(7Br)K) was performed to investigate this. A fluorescent probe was installed by chemoselective Suzuki–Miyaura cross-coupling of the 7-bromotryptophan and a poly(ethylene glycol) (PEG) linker was attached to the lysine residue. Flow cytometry and live cell imaging confirmed unspecific uptake of the small, non-PEGylated peptide, whereas the PEG5000 peptide conjugate unveiled a selective internalization by M21 cells overexpressing αvβ3 and no uptake in αv-deficient M21L cells. 相似文献
58.
Sustainable process design (SPD) problems combine a process design problem with life cycle assessment (LCA) to optimize process economics and life cycle environmental impacts. While SPD makes use of recent advances in process systems engineering and optimization, its use of LCA has stagnated. Currently, only process LCA is utilized in SPD, resulting in designs based on incomplete and potentially inaccurate life cycle information. To address these shortcomings, the multiscale process to planet (P2P) modeling framework is applied to formulate and solve the SPD problem. The P2P framework offers a more comprehensive analysis boundary than conventional SPD and greater modeling detail than advanced LCA methodologies. Benefits of applying this framework to SPD are demonstrated with an ethanol process design case study. Results show that current methods shift emissions outside the analysis boundary, while applying the P2P modeling framework results in environmentally superior process designs. Future extensions of the P2P framework are discussed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3320–3331, 2015 相似文献
59.
Per Kreuger Rebecca Steinert Olof Görnerup Daniel Gillblad 《International Journal of Network Management》2018,28(2)
Managing and balancing load in distributed systems remains a challenging problem in resource management, especially in networked systems where scalability concerns favour distributed and dynamic approaches. Distributed methods can also integrate well with centralised control paradigms if they provide high‐level usage statistics and control interfaces for supporting and deploying centralised policy decisions. We present a general method to compute target values for an arbitrary metric on the local system state and show that autonomous rebalancing actions based on the target values can be used to reliably and robustly improve the balance for metrics based on probabilistic risk estimates. To balance the trade‐off between balancing efficiency and cost, we introduce 2 methods of deriving rebalancing actuations from the computed targets that depend on parameters that directly affects the trade‐off. This enables policy level control of the distributed mechanism based on collected metric statistics from network elements. Evaluation results based on cellular radio access network simulations indicate that load balancing based on probabilistic overload risk metrics provides more robust balancing solutions with fewer handovers compared to a baseline setting based on average load. 相似文献
60.
Ivie L. Conlon Dr. Brandon Drennen Dr. Maryanna E. Lanning Samuel Hughes Rebecca Rothhaas Dr. Paul T. Wilder Dr. Alexander D. MacKerell Jr. Dr. Steven Fletcher 《ChemMedChem》2020,15(18):1691-1698
Protein–protein interactions (PPIs), many of which are dominated by α-helical recognition domains, play key roles in many essential cellular processes, and the dysregulation of these interactions can cause detrimental effects. For instance, aberrant PPIs involving the Bcl-2 protein family can lead to several diseases including cancer, neurodegenerative diseases, and diabetes. Interactions between Bcl-2 pro-life proteins, such as Mcl-1, and pro-death proteins, such as Bim, regulate the intrinsic pathway of apoptosis. p53, a tumor-suppressor protein, also has a pivotal role in apoptosis and is negatively regulated by its E3 ubiquitin ligase HDM2. Both Mcl-1 and HDM2 are upregulated in numerous cancers, and, interestingly, there is crosstalk between both protein pathways. Recently, synergy has been observed between Mcl-1 and HDM2 inhibitors. Towards the development of new anticancer drugs, we herein describe a polypharmacology approach for the dual inhibition of Mcl-1 and HDM2 by employing three densely functionalized isoxazoles, pyrazoles, and thiazoles as mimetics of key α-helical domains of their partner proteins. 相似文献