全文获取类型
收费全文 | 4429篇 |
免费 | 203篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 56篇 |
化学工业 | 1325篇 |
金属工艺 | 139篇 |
机械仪表 | 72篇 |
建筑科学 | 93篇 |
矿业工程 | 12篇 |
能源动力 | 127篇 |
轻工业 | 565篇 |
水利工程 | 11篇 |
石油天然气 | 9篇 |
无线电 | 88篇 |
一般工业技术 | 668篇 |
冶金工业 | 1073篇 |
原子能技术 | 22篇 |
自动化技术 | 375篇 |
出版年
2023年 | 38篇 |
2022年 | 171篇 |
2021年 | 279篇 |
2020年 | 98篇 |
2019年 | 84篇 |
2018年 | 150篇 |
2017年 | 152篇 |
2016年 | 160篇 |
2015年 | 122篇 |
2014年 | 163篇 |
2013年 | 267篇 |
2012年 | 182篇 |
2011年 | 227篇 |
2010年 | 146篇 |
2009年 | 130篇 |
2008年 | 130篇 |
2007年 | 130篇 |
2006年 | 78篇 |
2005年 | 63篇 |
2004年 | 70篇 |
2003年 | 55篇 |
2002年 | 52篇 |
2001年 | 29篇 |
2000年 | 30篇 |
1999年 | 27篇 |
1998年 | 191篇 |
1997年 | 210篇 |
1996年 | 141篇 |
1995年 | 97篇 |
1994年 | 50篇 |
1993年 | 73篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 21篇 |
1989年 | 17篇 |
1988年 | 18篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 33篇 |
1983年 | 23篇 |
1982年 | 42篇 |
1981年 | 48篇 |
1980年 | 57篇 |
1979年 | 29篇 |
1978年 | 37篇 |
1977年 | 110篇 |
1976年 | 239篇 |
1975年 | 14篇 |
1973年 | 12篇 |
排序方式: 共有4635条查询结果,搜索用时 0 毫秒
71.
72.
73.
Krzysztof Skowron Anna Budzyska Natalia Wiktorczyk-Kapischke Karolina Chomacka Katarzyna Grudlewska-Buda Monika Wilk Ewa Waecka-Zacharska Magorzata Andrzejewska Eugenia Gospodarek-Komkowska 《International journal of molecular sciences》2022,23(14)
Stress and anxiety are common phenomena that contribute to many nervous system dysfunctions. More and more research has been focusing on the importance of the gut–brain axis in the course and treatment of many diseases, including nervous system disorders. This review aims to present current knowledge on the influence of psychobiotics on the gut–brain axis based on selected diseases, i.e., Alzheimer’s disease, Parkinson’s disease, depression, and autism spectrum disorders. Analyses of the available research results have shown that selected probiotic bacteria affect the gut–brain axis in healthy people and people with selected diseases. Furthermore, supplementation with probiotic bacteria can decrease depressive symptoms. There is no doubt that proper supplementation improves the well-being of patients. Therefore, it can be concluded that the intestinal microbiota play a relevant role in disorders of the nervous system. The microbiota–gut–brain axis may represent a new target in the prevention and treatment of neuropsychiatric disorders. However, this topic needs more research. Such research could help find effective treatments via the modulation of the intestinal microbiome. 相似文献
74.
Agata Kaczmarek Anna Katarzyna Wroska Michalina Kazek Mieczysawa Irena Bogu 《International journal of molecular sciences》2022,23(9)
The food flavour additive octanoic acid (C8:0) is also a metabolite of the entomopathogenic fungus Conidiobolus coronatus, which efficiently infects and rapidly kills Galleria mellonella. GC-MS analysis confirmed the presence of C8:0 in insecticidal fraction FR3 extracted from C. coronatus filtrate. Topical administration of C8:0 had a dose-dependent effect on survival rates of larvae but not on pupation or adult eclosion times of the survivors. Topically applied C8:0 was more toxic to adults than larvae (LD100 for adults 18.33 ± 2.49 vs. 33.56 ± 2.57 µg/mg of body mass for larvae). The administration of C8:0 on the cuticle of larvae and adults, in amounts corresponding to their LD50 and LD100 doses, had a considerable impact on the two main defense systems engaged in protecting against pathogens, causing serious changes in the developmental-stage-specific profiles of free fatty acids (FFAs) covering the cuticle of larvae and adults and damaging larval hemocytes. In vitro cultures of G. mellonella hemocytes, either directly treated with C8:0 or taken from C8:0 treated larvae, revealed deformation of hemocytes, disordered networking, late apoptosis, and necrosis, as well as caspase 1–9 activation and elevation of 8-OHdG level. C8:0 was also confirmed to have a cytotoxic effect on the SF-9 insect cell line, as determined by WST-1 and LDH tests. 相似文献
75.
76.
Karolina Dydak Adam Junka Grzegorz Nowacki Justyna Paleczny Patrycja Szymczyk-Zikowska Aleksandra Grzyska Olga Anioek Marzenna Bartoszewicz 《International journal of molecular sciences》2022,23(9)
Hernia repairs are the most common abdominal wall elective procedures performed by general surgeons. Hernia-related postoperative infective complications occur with 10% frequency. To counteract the risk of infection emergence, the development of effective, biocompatible and antimicrobial mesh adjuvants is required. Therefore, the aim of our in vitro investigation was to evaluate the suitability of bacterial cellulose (BC) polymer coupled with gentamicin (GM) antibiotic as an absorbent layer of surgical mesh. Our research included the assessment of GM-BC-modified meshes’ cytotoxicity against fibroblasts ATCC CCL-1 and a 60-day duration cell colonisation measurement. The obtained results showed no cytotoxic effect of modified meshes. The quantified fibroblast cells levels resembled a bimodal distribution depending on the time of culturing and the type of mesh applied. The measured GM minimal inhibitory concentration was 0.47 µg/mL. Results obtained in the modified disc-diffusion method showed that GM-BC-modified meshes inhibited bacterial growth more effectively than non-coated meshes. The results of our study indicate that BC-modified hernia meshes, fortified with appropriate antimicrobial, may be applied as effective implants in hernia surgery, preventing risk of infection occurrence and providing a high level of biocompatibility with regard to fibroblast cells. 相似文献
77.
We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization models: the block replacement models, group maintenance models, and opportunistic maintenance models. Moreover, an example of a two-unit system maintenance process is provided in order to compare various maintenance policies. 相似文献
78.
Robust ordinal regression in preference learning and ranking 总被引:1,自引:0,他引:1
Salvatore Corrente Salvatore Greco Miłosz Kadziński Roman Słowiński 《Machine Learning》2013,93(2-3):381-422
Multiple Criteria Decision Aiding (MCDA) offers a diversity of approaches designed for providing the decision maker (DM) with a recommendation concerning a set of alternatives (items, actions) evaluated from multiple points of view, called criteria. This paper aims at drawing attention of the Machine Learning (ML) community upon recent advances in a representative MCDA methodology, called Robust Ordinal Regression (ROR). ROR learns by examples in order to rank a set of alternatives, thus considering a similar problem as Preference Learning (ML-PL) does. However, ROR implements the interactive preference construction paradigm, which should be perceived as a mutual learning of the model and the DM. The paper clarifies the specific interpretation of the concept of preference learning adopted in ROR and MCDA, comparing it to the usual concept of preference learning considered within ML. This comparison concerns a structure of the considered problem, types of admitted preference information, a character of the employed preference models, ways of exploiting them, and techniques to arrive at a final ranking. 相似文献
79.
Mikołaj Bojańczyk 《Theory of Computing Systems》2013,53(2):194-222
We develop an algebraic theory for languages of data words. We prove that, under certain conditions, a language of data words is definable in first-order logic if and only if its syntactic monoid is aperiodic. 相似文献
80.
The influence of thermal treatment, pickling and fermentation on the content of glucobrassicin and its selected breakdown products in broccoli and cauliflower was investigated. The highest content of glucobrassicin and the lowest content of its breakdown products were found in vegetables which underwent thermal treatment such as boiling and steam cooking. The lowest content of glucobrassicin and the highest content of its breakdown products were present in raw, pickled and fermented vegetables in which the myrosinase remained active. Ascrobigen was the major glucobrassicin breakdown product and its content was negatively correlated with glucobrassicin content in broccoli and cauliflower. After heating of vegetables in 60 °C for 20 min (causing thermal deactivation of epithiospecific protein) no presence of indole-3-acetonitrile was found. 相似文献