全文获取类型
收费全文 | 32820篇 |
免费 | 1412篇 |
国内免费 | 120篇 |
专业分类
电工技术 | 428篇 |
综合类 | 229篇 |
化学工业 | 6121篇 |
金属工艺 | 702篇 |
机械仪表 | 759篇 |
建筑科学 | 1145篇 |
矿业工程 | 102篇 |
能源动力 | 1080篇 |
轻工业 | 4522篇 |
水利工程 | 287篇 |
石油天然气 | 175篇 |
武器工业 | 6篇 |
无线电 | 2525篇 |
一般工业技术 | 4753篇 |
冶金工业 | 6396篇 |
原子能技术 | 256篇 |
自动化技术 | 4866篇 |
出版年
2024年 | 59篇 |
2023年 | 204篇 |
2022年 | 647篇 |
2021年 | 964篇 |
2020年 | 670篇 |
2019年 | 758篇 |
2018年 | 854篇 |
2017年 | 914篇 |
2016年 | 905篇 |
2015年 | 718篇 |
2014年 | 1066篇 |
2013年 | 1821篇 |
2012年 | 1579篇 |
2011年 | 1964篇 |
2010年 | 1449篇 |
2009年 | 1465篇 |
2008年 | 1336篇 |
2007年 | 1171篇 |
2006年 | 943篇 |
2005年 | 961篇 |
2004年 | 1001篇 |
2003年 | 912篇 |
2002年 | 869篇 |
2001年 | 738篇 |
2000年 | 583篇 |
1999年 | 558篇 |
1998年 | 2079篇 |
1997年 | 1345篇 |
1996年 | 950篇 |
1995年 | 626篇 |
1994年 | 489篇 |
1993年 | 545篇 |
1992年 | 227篇 |
1991年 | 290篇 |
1990年 | 234篇 |
1989年 | 201篇 |
1988年 | 211篇 |
1987年 | 161篇 |
1986年 | 167篇 |
1985年 | 186篇 |
1984年 | 131篇 |
1983年 | 97篇 |
1982年 | 120篇 |
1981年 | 129篇 |
1980年 | 119篇 |
1979年 | 93篇 |
1978年 | 76篇 |
1977年 | 145篇 |
1976年 | 229篇 |
1975年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
Giulia Minniti Letícia Maria Pescinini-Salzedas Guilherme Almeida dos Santos Minniti Lucas Fornari Laurindo Sandra Maria Barbalho Renata Vargas Sinatora Lance Alan Sloan Rafael Santos de Argollo Haber Adriano Cressoni Araújo Karina Quesada Jesselina F. dos Santos Haber Marcelo Dib Bechara Katia Portero Sloan 《International journal of molecular sciences》2022,23(21)
Sarcopenia is a disease that becomes more prevalent as the population ages, since it is directly linked to the process of senility, which courses with muscle atrophy and loss of muscle strength. Over time, sarcopenia is linked to obesity, being known as sarcopenic obesity, and leads to other metabolic changes. At the molecular level, organokines act on different tissues and can improve or harm sarcopenia. It all depends on their production process, which is associated with factors such as physical exercise, the aging process, and metabolic diseases. Because of the seriousness of these repercussions, the aim of this literature review is to conduct a review on the relationship between organokines, sarcopenia, diabetes, and other metabolic repercussions, as well the role of physical exercise. To build this review, PubMed-Medline, Embase, and COCHRANE databases were searched, and only studies written in English were included. It was observed that myokines, adipokines, hepatokines, and osteokines had direct impacts on the pathophysiology of sarcopenia and its metabolic repercussions. Therefore, knowing how organokines act is very important to know their impacts on age, disease prevention, and how they can be related to the prevention of muscle loss. 相似文献
892.
Catarina M. Morais Ana M. Cardoso Ana Rita D. Araújo Ana Reis Pedro Domingues Maria Rosrio M. Domingues Maria C. Pedroso de Lima Amlia S. Jurado 《International journal of molecular sciences》2022,23(21)
Modulation of lipid metabolism is a well-established cancer hallmark, and SCD1 has been recognized as a key enzyme in promoting cancer cell growth, including in glioblastoma (GBM), the deadliest brain tumor and a paradigm of cancer resistance. The central goal of this work was to identify, by MS, the phospholipidome alterations resulting from the silencing of SCD1 in human GBM cells, in order to implement an innovative therapy to fight GBM cell resistance. With this purpose, RNAi technology was employed, and low serum-containing medium was used to mimic nutrient deficiency conditions, at which SCD1 is overexpressed. Besides the expected increase in the saturated to unsaturated fatty acid ratio in SCD1 silenced-GBM cells, a striking increase in polyunsaturated chains, particularly in phosphatidylethanolamine and cardiolipin species, was noticed and tentatively correlated with an increase in autophagy (evidenced by the increase in LC3BII/I ratio). The contribution of autophagy to mitigate the impact of SCD1 silencing on GBM cell viability and growth, whose modest inhibition could be correlated with the maintenance of energetically associated mitochondria, was evidenced by using autophagy inhibitors. In conclusion, SCD1 silencing could constitute an important tool to halt GBM resistance to the available treatments, especially when coupled with a mitochondria disrupter chemotherapeutic. 相似文献
893.
Juan García-Bernalt Diego Pedro Fernndez-Soto Antonio Muro 《International journal of molecular sciences》2022,23(22)
Since the onset of the COVID-19 pandemic, over 610 million cases have been diagnosed and it has caused over 6.5 million deaths worldwide. The crisis has forced the scientific community to develop tools for disease control and management at a pace never seen before. The control of the pandemic heavily relies in the use of fast and accurate diagnostics, that allow testing at a large scale. The gold standard diagnosis of viral infections is the RT-qPCR. Although it provides consistent and reliable results, it is hampered by its limited throughput and technical requirements. Here, we discuss the main approaches to rapid and point-of-care diagnostics based on RT-qPCR and isothermal amplification diagnostics. We describe the main COVID-19 molecular diagnostic tests approved for self-testing at home or for point-of-care testing and compare the available options. We define the influence of specimen selection and processing, the clinical validation, result readout improvement strategies, the combination with CRISPR-based detection and the diagnostic challenge posed by SARS-CoV-2 variants for different isothermal amplification techniques, with a particular focus on LAMP and recombinase polymerase amplification (RPA). Finally, we try to shed light on the effect the improvement in molecular diagnostics during the COVID-19 pandemic could have in the future of other infectious diseases. 相似文献
894.
895.
Karine Loth Nicolas Parisot Franoise Paquet Hugo Terrasson Catherine Sivignon Isabelle Rahioui Mlanie Ribeiro Lopes Karen Gaget Gabrielle Duport Agns F. Delmas Vincent Aucagne Abdelaziz Heddi Federica Calevro Pedro da Silva 《International journal of molecular sciences》2022,23(20)
Aphids (Hemiptera: Aphidoidea) are among the most detrimental insects for agricultural plants, and their management is a great challenge in agronomical research. A new class of proteins, called Bacteriocyte-specific Cysteine-Rich (BCR) peptides, provides an alternative to chemical insecticides for pest control. BCRs were initially identified in the pea aphid Acyrthosiphon pisum. They are small disulfide bond-rich proteins expressed exclusively in aphid bacteriocytes, the insect cells that host intracellular symbiotic bacteria. Here, we show that one of the A. pisum BCRs, BCR4, displays prominent insecticidal activity against the pea aphid, impairing insect survival and nymphal growth, providing evidence for its potential use as a new biopesticide. Our comparative genomics and phylogenetic analyses indicate that BCRs are restricted to the aphid lineage. The 3D structure of BCR4 reveals that this peptide belongs to an as-yet-unknown structural class of peptides and defines a new superfamily of defensins. 相似文献
896.
Srgio R. S. Veloso Raquel G. D. Andrade Valria Gomes Carlos O. Amorim Vítor S. Amaral Vernica Salgueirio Paulo J. G. Coutinho Paula M. T. Ferreira Miguel A. Correa-Duarte Elisabete M. S. Castanheira 《International journal of molecular sciences》2022,23(22)
Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (CaxMn1−xFe2O4) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy. 相似文献
897.
898.
Natlia Lins da Silva-Gomes Leonardo Alexandre de Souza Ruivo Claudia Moreira Marcelo Meuser-Batista Cristiane Frana da Silva Denise da Gama Jaen Batista Stênio Fragoso Gabriel Melo de Oliveira Maria de Nazar Correia Soeiro Otacilio C. Moreira 《International journal of molecular sciences》2022,23(23)
Ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are enzymes located on the surface of the T. cruzi plasma membrane, which hydrolyze a wide range of tri-/-diphosphate nucleosides. In this work, we used previously developed genetically modified strains of Trypanosoma cruzi (T. cruzi), hemi-knockout (KO +/−) and overexpressing (OE) the TcNTPDase-1 gene to evaluate the parasite infectivity profile in a mouse model of acute infection (n = 6 mice per group). Our results showed significantly higher parasitemia and mortality, and lower weight in animals infected with parasites OE TcNTPDase-1, as compared to the infection with the wild type (WT) parasites. On the other hand, animals infected with (KO +/−) parasites showed no mortality during the 30-day trial and mouse weight was more similar to the non-infected (NI) animals. In addition, they had low parasitemia (45.7 times lower) when compared with parasites overexpressing TcNTPDase-1 from the hemi-knockout (OE KO +/−) group. The hearts of animals infected with the OE KO +/− and OE parasites showed significantly larger regions of cardiac inflammation than those infected with the WT parasites (p < 0.001). Only animals infected with KO +/− did not show individual electrocardiographic changes during the period of experimentation. Together, our results expand the knowledge on the role of NTPDases in T. cruzi infectivity, reenforcing the potential of this enzyme as a chemotherapy target to treat Chagas disease (CD). 相似文献
899.
Enrico Rebufello Fabrizio Piacentini Alessio Avella Muriel A.de Souza Marco Gramegna Jan Dziewior Eliahu Cohen Lev Vaidman Ivo Pietro Degiovanni Marco Genovese 《光:科学与应用(英文版)》2021,10(6):963-968
Is it possible that a measurement of a spin component of a spin-1/2 particle yields the value 100? In 1988 Aharonov, Albert and Vaidman argued that upon pre-and... 相似文献
900.
Natasha de Alwis Bianca R. Fato Sally Beard Natalie K. Binder Tuuhevaha J. Kaituu-Lino Kenji Onda Natalie J. Hannan 《International journal of molecular sciences》2022,23(17)
Previously, we demonstrated that the proton pump inhibitor, esomeprazole magnesium hydrate (MH), could have potential as a repurposed treatment against preeclampsia, a serious obstetric condition. In this study we investigate the difference in the preclinical effectiveness between 100 µM of esomeprazole MH and its hydration isomer, esomeprazole magnesium trihydrate (MTH). Here, we found that both treatments reduced secretion of sFLT-1 (anti-angiogenic factor) from primary cytotrophoblast, but only esomeprazole MH reduced sFLT-1 secretion from primary human umbilical vein endothelial cells (assessed via ELISA). Both drugs could mitigate expression of the endothelial dysfunction markers, vascular cell adhesion molecule-1 and endothelin-1 (via qPCR). Neither esomeprazole MH nor MTH quenched cytotrophoblast reactive oxygen species production in response to sodium azide (ROS assay). Finally, using wire myography, we demonstrated that both compounds were able to induce vasodilation of human omental arteries at 100 µM. Esomeprazole is safe to use in pregnancy and a candidate treatment for preeclampsia. Using primary human tissues and cells, we validated that esomeprazole is effective in enhancing vascular relaxation, and can reduce key factors associated with preeclampsia, including sFLT-1 and endothelial dysfunction. However, esomeprazole MH was more efficacious than esomeprazole MTH in our in vitro studies. 相似文献