全文获取类型
收费全文 | 21275篇 |
免费 | 900篇 |
国内免费 | 310篇 |
专业分类
电工技术 | 471篇 |
综合类 | 545篇 |
化学工业 | 3870篇 |
金属工艺 | 518篇 |
机械仪表 | 734篇 |
建筑科学 | 888篇 |
矿业工程 | 185篇 |
能源动力 | 588篇 |
轻工业 | 2139篇 |
水利工程 | 252篇 |
石油天然气 | 178篇 |
武器工业 | 27篇 |
无线电 | 2416篇 |
一般工业技术 | 2910篇 |
冶金工业 | 3680篇 |
原子能技术 | 174篇 |
自动化技术 | 2910篇 |
出版年
2024年 | 74篇 |
2023年 | 138篇 |
2022年 | 380篇 |
2021年 | 496篇 |
2020年 | 320篇 |
2019年 | 345篇 |
2018年 | 401篇 |
2017年 | 379篇 |
2016年 | 419篇 |
2015年 | 365篇 |
2014年 | 559篇 |
2013年 | 1045篇 |
2012年 | 814篇 |
2011年 | 992篇 |
2010年 | 766篇 |
2009年 | 829篇 |
2008年 | 807篇 |
2007年 | 830篇 |
2006年 | 717篇 |
2005年 | 622篇 |
2004年 | 692篇 |
2003年 | 904篇 |
2002年 | 1200篇 |
2001年 | 1021篇 |
2000年 | 590篇 |
1999年 | 538篇 |
1998年 | 1332篇 |
1997年 | 859篇 |
1996年 | 633篇 |
1995年 | 430篇 |
1994年 | 317篇 |
1993年 | 350篇 |
1992年 | 193篇 |
1991年 | 153篇 |
1990年 | 147篇 |
1989年 | 133篇 |
1988年 | 131篇 |
1987年 | 109篇 |
1986年 | 113篇 |
1985年 | 151篇 |
1984年 | 88篇 |
1983年 | 92篇 |
1982年 | 85篇 |
1981年 | 102篇 |
1980年 | 100篇 |
1979年 | 62篇 |
1977年 | 102篇 |
1976年 | 192篇 |
1975年 | 51篇 |
1973年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Margherita Passariello Veronica Ferrucci Emanuele Sasso Lorenzo Manna Rosa Rapuano Lembo Stefano Pascarella Giovanna Fusco Nicola Zambrano Massimo Zollo Claudia De Lorenzo 《International journal of molecular sciences》2022,23(10)
The dramatic experience with SARS-CoV-2 has alerted the scientific community to be ready to face new epidemics/pandemics caused by new variants. Among the therapies against the pandemic SARS-CoV-2 virus, monoclonal Antibodies (mAbs) targeting the Spike glycoprotein have represented good drugs to interfere in the Spike/ Angiotensin Converting Enzyme-2 (ACE-2) interaction, preventing virus cell entry and subsequent infection, especially in patients with a defective immune system. We obtained, by an innovative phage display selection strategy, specific binders recognizing different epitopes of Spike. The novel human antibodies specifically bind to Spike-Receptor Binding Domain (RBD) in a nanomolar range and interfere in the interaction of Spike with the ACE-2 receptor. We report here that one of these mAbs, named D3, shows neutralizing activity for virus infection in cell cultures by different SARS-CoV-2 variants and retains the ability to recognize the Omicron-derived recombinant RBD differently from the antibodies Casirivimab or Imdevimab. Since anti-Spike mAbs, used individually, might be unable to block the virus cell entry especially in the case of resistant variants, we investigated the possibility to combine D3 with the antibody in clinical use Sotrovimab, and we found that they recognize distinct epitopes and show additive inhibitory effects on the interaction of Omicron-RBD with ACE-2 receptor. Thus, we propose to exploit these mAbs in combinatorial treatments to enhance their potential for both diagnostic and therapeutic applications in the current and future pandemic waves of coronavirus. 相似文献
52.
Trimethylsilyl derivatives of starch, amylose, amylopectin, and glycogen have been prepared by using hexamethyldisilazane as the silylating reagent and formamide as solvent. The degree of silylation ranged from 0.9 to 2.2 and is believed to be dependent on the structure and solubility of the polysaccharide. An important property of these trimethylsilyl derivatives is their complete solubility in common organic solvents like benzene, toluene, chloroform, etc. 相似文献
53.
Anna Michelotti Marco de Scordilli Elisa Bertoli Elisa De Carlo Alessandro Del Conte Alessandra Bearz 《International journal of molecular sciences》2022,23(12)
Standard treatment for advanced non-small cell lung cancer (NSCLC) historically consisted of systemic cytotoxic chemotherapy until the early 2000s, when precision medicine led to a revolutionary change in the therapeutic scenario. The identification of oncogenic driver mutations in EGFR, ALK and ROS1 rearrangements identified a subset of patients who largely benefit from targeted agents. However, since the proportion of patients with druggable alterations represents a minority, the discovery of new potential driver mutations is still an urgent clinical need. We provide a comprehensive review of the emerging molecular targets in NSCLC and their applications in the advanced setting. 相似文献
54.
Vincenzo Fiorentino Pietro Tralongo Maurizio Martini Silvia Betti Elena Rossi Francesco Pierconti Valerio De Stefano Luigi Maria Larocca 《International journal of molecular sciences》2022,23(14)
Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) represent a group of hematological disorders that are traditionally considered as indistinct slow progressing conditions; still, a subset of cases shows a rapid evolution towards myelofibrotic bone marrow failure. Specific abnormalities in the megakaryocyte lineage seem to play a central role in this evolution, especially in the bone marrow fibrosis but also in the induction of myeloproliferation. In this review, we analyze the current knowledge of prognostic factors of MPNs related to their evolution to myelofibrotic bone marrow failure. Moreover, we focused the role of the megakaryocytic lineage in the various stages of MPNs, with updated examples of MPNs in vitro and in vivo models and new therapeutic implications. 相似文献
55.
Silvio Borrelli Ida Matarazzo Eugenio Lembo Laura Peccarino Claudia Annoiato Maria Rosaria Scognamiglio Andrea Foderini Chiara Ruotolo Aldo Franculli Federica Capozzi Pavlo Yavorskiy Fatme Merheb Michele Provenzano Gaetano La Manna Luca De Nicola Roberto Minutolo Carlo Garofalo 《International journal of molecular sciences》2022,23(12)
Increasing potassium intake ameliorates blood pressure (BP) and cardiovascular (CV) prognoses in the general population; therefore the World Health Organization recommends a high-potassium diet (90–120 mEq/day). Hyperkalaemia is a rare condition in healthy individuals due to the ability of the kidneys to effectively excrete dietary potassium load in urine, while an increase in serum K+ is prevalent in patients with chronic kidney disease (CKD). Hyperkalaemia prevalence increases in more advanced CKD stages, and is associated with a poor prognosis. This scenario generates controversy on the correct nutritional approach to hyperkalaemia in CKD patients, considering the unproven link between potassium intake and serum K+ levels. Another concern is that drug-induced hyperkalaemia leads to the down-titration or withdrawal of renin-angiotensin system inhibitors (RASI) and mineralocorticoids receptors antagonists (MRA) in patients with CKD, depriving these patients of central therapeutic interventions aimed at delaying CKD progression and decreasing CV mortality. The new K+-binder drugs (Patiromer and Sodium-Zirconium Cyclosilicate) have proven to be adequate and safe therapeutic options to control serum K+ in CKD patients, enabling RASI and MRA therapy, and possibly, a more liberal intake of fruit and vegetables. 相似文献
56.
Lorenzo Vannozzi Alessandro Lucantonio Arturo Castillo Antonio De Simone Leonardo Ricotti 《International journal of molecular sciences》2022,23(15)
In this work, an innovative model is proposed as a design tool to predict both the inner and outer radii in rolled structures based on polydimethylsiloxane bilayers. The model represents an improvement of Timoshenko’s formula taking into account the friction arising from contacts between layers arising from rolling by more than one turn, hence broadening its application field towards materials based on elastomeric bilayers capable of large deformations. The fabricated structures were also provided with surface topographical features that would make them potentially usable in different application scenarios, including cell/tissue engineering ones. The bilayer design parameters were varied, such as the initial strain (from 20 to 60%) and the bilayer thickness (from 373 to 93 µm). The model matched experimental data on the inner and outer radii nicely, especially when a high friction condition was implemented in the model, particularly reducing the error below 2% for the outer diameter while varying the strain. The model outperformed the current literature, where self-penetration is not excluded, and a single value of the radius of spontaneous rolling is used to describe multiple rolls. A complex 3D bioinspired hierarchical elastomeric microstructure made of seven spirals arranged like a hexagon inscribed in a circumference, similar to typical biological architectures (e.g., myofibrils within a sarcolemma), was also developed. In this case also, the model effectively predicted the spirals’ features (error smaller than 18%), opening interesting application scenarios in the modeling and fabrication of bioinspired materials. 相似文献
57.
Suzanne N. Voorrips Huitzilihuitl Saucedo-Orozco Pablo I. Snchez-Aguilera Rudolf A. De Boer Peter Van der Meer B. Daan Westenbrink 《International journal of molecular sciences》2022,23(15)
Despite the constant improvement of therapeutical options, heart failure (HF) remains associated with high mortality and morbidity. While new developments in guideline-recommended therapies can prolong survival and postpone HF hospitalizations, impaired exercise capacity remains one of the most debilitating symptoms of HF. Exercise intolerance in HF is multifactorial in origin, as the underlying cardiovascular pathology and reactive changes in skeletal muscle composition and metabolism both contribute. Recently, sodium-related glucose transporter 2 (SGLT2) inhibitors were found to improve cardiovascular outcomes significantly. Whilst much effort has been devoted to untangling the mechanisms responsible for these cardiovascular benefits of SGLT2 inhibitors, little is known about the effect of SGLT2 inhibitors on exercise performance in HF. This review provides an overview of the pathophysiological mechanisms that are responsible for exercise intolerance in HF, elaborates on the potential SGLT2-inhibitor-mediated effects on these phenomena, and provides an up-to-date overview of existing studies on the effect of SGLT2 inhibitors on clinical outcome parameters that are relevant to the assessment of exercise capacity. Finally, current gaps in the evidence and potential future perspectives on the effects of SGLT2 inhibitors on exercise intolerance in chronic HF are discussed. 相似文献
58.
Elisa Boschetti Leonardo Caporali Roberto DAngelo Carolina Malagelada Anna Accarino Maria Teresa Dotti Roberta Costa Giovanna Cenacchi Loris Pironi Rita Rinaldi Vincenzo Stanghellini Stefano Ratti Lucia Manzoli Valerio Carelli Roberto De Giorgio 《International journal of molecular sciences》2022,23(15)
mitochondrial neuro-gastrointestinal encephalomyopathy (MNGIE) is a rare genetic disorder characterized by thymidine phosphorylase (TP) enzyme defect. The absence of TP activity induces the imbalance of mitochondrial nucleotide pool, leading to impaired mitochondrial DNA (mtDNA) replication and depletion. Since mtDNA is required to ensure oxidative phosphorylation, metabolically active tissues may not achieve sufficient energy production. The only effective life-saving approach in MNGIE has been the permanent replacement of TP via allogeneic hematopoietic stem cell or liver transplantation. However, the follow-up of transplanted patients showed that gut tissue changes do not revert and fatal complications, such as massive gastrointestinal bleeding, can occur. The purpose of this study was to clarify whether the reintroduction of TP after transplant can recover mtDNA copy number in a normal range. Using laser capture microdissection and droplet-digital-PCR, we assessed the mtDNA copy number in each layer of full-thickness ileal samples of a naive MNGIE cohort vs. controls and in a patient pre- and post-TP replacement. The treatment led to a significant recovery of gut tissue mtDNA amount, thus showing its efficacy. Our results indicate that a timely TP replacement is needed to maximize therapeutic success before irreversible degenerative tissue changes occur in MNGIE. 相似文献
59.
Francisco J. Osuna-Prieto Francisco M. Acosta Unai A. Perez de Arrilucea Le Floch Blanca Riquelme-Gallego Elisa Merchan-Ramirez Huiwen Xu Juan Carlos De La Cruz-Mrquez Francisco J. Amaro-Gahete Jose A. Llamas-Elvira Eva M. Trivio-Ibez Antonio Segura-Carretero Jonatan R Ruiz 《Journal of the International Society of Sports Nutrition》2022,19(1):417
60.
Rafael Xavier Lisandro Zambenedetti Granville Filip De Turck Bruno Volckaert 《International Journal of Network Management》2019,29(4)
Audio and video (A/V) collaboration platforms often use Internet cloud technologies to ensure elasticity. They generally operate on a best‐effort basis, without quality or delivery guarantees. However, such guarantees are a premise of business‐focused platforms, which often rely on static/dedicated infrastructure and hardware‐based components. This article presents results obtained in the final stage of the Elastic Media Distribution (EMD) project, which targets the migration of a business‐focused hardware‐based A/V collaboration tool towards a more elastic, reliable, and secure cloud‐based model. The use case under investigation is an educational scenario: teachers and students located at distributed sites collaborate under different data encryption policies. An existing model of collaboration streaming is extended to accommodate encryption‐enabled streaming components, and new resource allocation heuristics are proposed to deploy these components under stringent service level agreement (SLA) constraints. An extended version of our evaluation framework, based on the CloudSim simulator, manages encryption‐enabled components. A resource usage dataset was obtained by prototyping selected streaming components and evaluating their performance on the Virtual Wall large‐scale test bed. This dataset is fed into the extended simulation framework. Simulation results show longer than expected delays when loading streaming components, an issue that jeopardises the user experience that can be alleviated by the algorithms proposed in this article. Results show that the proposed algorithms enable policy‐based secured communications under bandwidth and virtual machine (VM) cost increases of 48% and 23%, respectively, if compared with a nonencrypted previous solution, and with set‐up times remaining under the required 2‐second deadline. 相似文献