全文获取类型
收费全文 | 2697篇 |
免费 | 186篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 19篇 |
化学工业 | 753篇 |
金属工艺 | 51篇 |
机械仪表 | 70篇 |
建筑科学 | 102篇 |
矿业工程 | 11篇 |
能源动力 | 94篇 |
轻工业 | 429篇 |
水利工程 | 21篇 |
石油天然气 | 10篇 |
无线电 | 176篇 |
一般工业技术 | 396篇 |
冶金工业 | 152篇 |
原子能技术 | 25篇 |
自动化技术 | 577篇 |
出版年
2024年 | 8篇 |
2023年 | 43篇 |
2022年 | 105篇 |
2021年 | 143篇 |
2020年 | 88篇 |
2019年 | 102篇 |
2018年 | 117篇 |
2017年 | 101篇 |
2016年 | 138篇 |
2015年 | 88篇 |
2014年 | 149篇 |
2013年 | 236篇 |
2012年 | 196篇 |
2011年 | 196篇 |
2010年 | 146篇 |
2009年 | 134篇 |
2008年 | 125篇 |
2007年 | 121篇 |
2006年 | 79篇 |
2005年 | 66篇 |
2004年 | 73篇 |
2003年 | 47篇 |
2002年 | 60篇 |
2001年 | 33篇 |
2000年 | 27篇 |
1999年 | 21篇 |
1998年 | 38篇 |
1997年 | 31篇 |
1996年 | 19篇 |
1995年 | 26篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有2886条查询结果,搜索用时 15 毫秒
61.
Catarina Almeida-Ferreira Rafael Silva-Teixeira Ana Cristina Gonalves Carlos Miguel Marto Ana Bela Sarmento-Ribeiro Francisco Caramelo Maria Filomena Botelho Mafalda Laranjo 《International journal of molecular sciences》2022,23(3)
Breast cancer (BC) is a malignant neoplasia with the highest incidence and mortality rates in women worldwide. Currently, therapies include surgery, radiotherapy, and chemotherapy, including targeted therapies in some cases. However, treatments are often associated with serious adverse effects. Looking for new options in BC treatment, we evaluated the therapeutic potential of cold atmospheric plasma (CAP) in two cell lines (MCF7 and HCC1806) with distinct histological features. Apoptosis seemed to be the most prevalent type of death, as corroborated by several biochemical features, including phosphatidylserine exposure, the disruption of mitochondrial membrane potential, an increase in BAX/BCL2 ratio and procaspase 3 loss. Moreover, the accumulation of cells in the G2/M phase of the cell cycle points to the loss of replication ability and decreased survival. Despite reported toxic concentrations of peroxides in culture media exposed to plasma, intracellular peroxide concentration was overall decreased accompanying a reduction in GSH levels shortly after plasma exposure in both cell lines. In HCC1806, elevated nitric oxide (NO) concentration accompanied by reduced superoxide levels suggests that these cells are capable of converting plasma-derived nitrites into NO that competes with superoxide dismutase (SOD) for superoxide to form peroxinitrite. The concomitant inhibition of the antioxidative activity of cells during CAP treatment, particularly the inhibition of cytochrome c oxidase with sodium azide, synergistically increased plasma toxicity. Thus, this in vitro research enlightens the therapeutic potential of CAP in the treatment of breast cancer, elucidating its possible mechanisms of action. 相似文献
62.
Rafael Raphaela Azevedo Noronha Fábio Bellot Gaspar Alexandre Barros 《Topics in Catalysis》2020,63(11-14):1066-1076
Topics in Catalysis - This work investigated the photodegradation of bromophenol blue (BPB) and indigo carmine (IC) dye under UV–Visible light using pure oxides of titanium and niobium, as... 相似文献
63.
Laís Reis-das-Mercês Tatiana Vinasco-Sandoval Rafael Pompeu Aline Cruz Ramos Ana K. M. Anaissi Samia Demachki Paulo Pimentel de Assumpo Amanda F. Vidal ndrea Ribeiro-dos-Santos Leandro Magalhes 《International journal of molecular sciences》2022,23(2)
Gastric cancer (GC) is the fifth most common type of cancer and the third leading cause of cancer death in the world. It is a disease that encompasses a variety of molecular alterations, including in non-coding RNAs such as circular RNAs (circRNAs). In the present study, we investigated hsa_circ_0000211, hsa_circ_0000284, hsa_circ_0000524, hsa_circ_0001136 and hsa_circ_0004771 expression profiles using RT-qPCR in 71 gastric tissue samples from GC patients (tumor and tumor-adjacent samples) and volunteers without cancer. In order to investigate the suitability of circRNAs as minimally invasive biomarkers, we also evaluated their expression profile through RT-qPCR in peripheral blood samples from patients with and without GC (n = 41). We also investigated the predicted interactions between circRNA-miRNA-mRNA and circRNA-RBP using the KEGG and Reactome databases. Overall, our results showed that hsa_circ_0000211, hsa_circ_0000284 and hsa_circ_0004771 presented equivalent expression profiles when analyzed by different methods (RNA-Seq and RT-qPCR) and different types of samples (tissue and blood). Further, functional enrichment results identified important signaling pathways related to GC. Thus, our data support the consideration of circRNAs as new, minimally invasive biomarkers capable of aiding in the diagnosis of GC and with great potential to be applied in clinical practice. 相似文献
64.
Diane Cleydes Baía da Silva Leonardo Oliveira Bittencourt Daiane Claydes Baia-da-Silva Victoria Santos Chemelo Luciana Eir-Quirino Priscila Cunha Nascimento Mrcia Cristina Freitas Silva Marco Aurelio M. Freire Walace Gomes-Leal Maria Elena Crespo-Lopez Rafael Rodrigues Lima 《International journal of molecular sciences》2022,23(7)
Methylmercury (MeHg) is one of the most dangerous toxic pollutants spread throughout the earth. Chronic MeHg intoxication by contaminated food ingestion is the most common threat to human health, including impairment to the developing fetus. The present study aims at investigating the effects of maternal exposure to MeHg during gestation and lactation on the spinal cord of offspring. Pregnant rats received oral doses of MeHg (40 μg/kg/day) over a period of 42 days (21 gestation and 21 lactation). Control animals received the vehicle only. Total mercury concentration was measured in blood samples from offspring collected at the 41st postnatal day. Counting of motor neurons and immunoreactivity for myelin basic protein (MBP) were assessed in the spinal cords in both control and MeHg-intoxicated animals. Our results showed that MeHg promoted an increase in blood Hg levels. In addition, it caused a reduction in the number of spinal cord motor neurons as well as decreased MBP immunoreactivity in the cervical, thoracic and lumbar segments. Our present findings suggest that MeHg intoxication during rat pregnancy and lactation is associated with a pattern of motor neuron degeneration and downregulation of myelin basic protein in different segments of a developing spinal cord. Further studies are needed to establish the effect of MeHg intoxication in both young and adult rats. 相似文献
65.
Deiweson Souza-Monteiro Mrcia Cristina dos Santos Guerra Leonardo Oliveira Bittencourt Walessa Alana Bragana Arago Aline Dionizio Felipe Martins Silveira Marília Afonso Rebelo Buzalaf Manoela Domingues Martins Maria Elena Crespo-Lopez Rafael Rodrigues Lima 《International journal of molecular sciences》2022,23(4)
Aluminum (Al) is one of the most abundant elements on Earth, and its high extraction rate and industrial use make human exposure very common. As Al may be a human toxicant, it is important to investigate the effects of Al exposure, mainly at low doses and for prolonged periods, by simulating human exposure. This work aimed to study the effects of low-dose exposure to chloride aluminum (AlCl3) on the oxidative biochemistry, proteomic profile, and morphology of the major salivary glands. Wistar male rats were exposed to 8.3 mg/kg/day of AlCl3 via intragastric gavage for 60 days. Then, the parotid and submandibular glands were subjected to biochemical assays, proteomic evaluation, and histological analysis. Al caused oxidative imbalance in both salivary glands. Dysregulation of protein expression, mainly of those related to cytoarchitecture, energy metabolism and glandular function, was detected in both salivary glands. Al also promoted histological alterations, such as acinar atrophy and an increase in parenchymal tissue. Prolonged exposure to Al, even at low doses, was able to modulate molecular alterations associated with morphological impairments in the salivary glands of rats. From this perspective, prolonged Al exposure may be a risk to exposed populations and their oral health. 相似文献
66.
This paper presents a model of approach for agroindustrial development utilizing geothermal energy in an agriculturally based tropical developing country. Presented is the complexity of patterns in raw materials productivity, demand and the present problems of preserving their quality from biological deterioration thru drying.Utilization of a geothermal agroindustrial estate have to be carefully studied and programmed in reply to an almost constant heat demand profile consistent with seasonal available raw materials. This study uses the Tongonan Geothermal Field in Leyte Island as the model for presentation. 相似文献
67.
Scientometrics - The theme related to the oil production in the Brazilian territory is not limited to the extraction means, distribution and use of this product, and involves political, cultural... 相似文献
68.
Patricia Kandus Priscilla Gail Minotti Natalia Soledad Morandeira Rafael Grimson Gabriela González Trilla Eliana Belén González 《International journal of remote sensing》2018,39(4):993-1016
South America has a large proportion of wetlands compared with other continents. While most of these wetlands were conserved in a relatively good condition until a few decades ago, pressures brought about by land use and climate change have threaten their integrity in recent years. The aim of this article is to provide a bibliometric analysis of the available scientific literature relating to the remote sensing of wetlands in South America. From 1960 to 2015, 153 articles were published in 63 different journals, with the number of articles published per year increasing progressively since 1990. This rise is also paralleled by an increase in the contribution of local authors. The most intensively studied regions are the wetland macrosystems of South American mega-rivers: the Amazon and Paraná Rivers, along with the Pantanal at the headwaters of Paraguay River. Few studies spanned more than two countries. The most frequent objectives were mapping, covering all types of wetlands with optical data, and hydrology, focusing on floodplain wetlands with microwave data as the preferred data source. The last decade substantial growth reflects an increase in technological and scientific capacities. Nevertheless, the state of the art regarding the remote sensing of wetlands in South America remains enigmatic. Fundamental questions and guidelines which may contribute to the understanding of the functioning of these ecosystems are yet to be fully defined and there is considerable dispersion in the use of data and remote-sensing approaches. 相似文献
69.
70.
Damaceno Rafael J. P. Rossi Luciano Mugnaini Rogério Mena-Chalco Jesús P. 《Scientometrics》2019,119(1):303-333
Scientometrics - Science can be examined from several standpoints, such as through a bibliometric analysis of the scientific output of researchers, research groups or institutions. However, there... 相似文献