全文获取类型
收费全文 | 630篇 |
免费 | 76篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 257篇 |
金属工艺 | 8篇 |
机械仪表 | 13篇 |
建筑科学 | 27篇 |
能源动力 | 20篇 |
轻工业 | 169篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 30篇 |
一般工业技术 | 93篇 |
冶金工业 | 8篇 |
自动化技术 | 73篇 |
出版年
2024年 | 1篇 |
2023年 | 19篇 |
2022年 | 4篇 |
2021年 | 90篇 |
2020年 | 37篇 |
2019年 | 28篇 |
2018年 | 42篇 |
2017年 | 27篇 |
2016年 | 44篇 |
2015年 | 30篇 |
2014年 | 34篇 |
2013年 | 57篇 |
2012年 | 36篇 |
2011年 | 58篇 |
2010年 | 32篇 |
2009年 | 34篇 |
2008年 | 30篇 |
2007年 | 18篇 |
2006年 | 21篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1985年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有706条查询结果,搜索用时 31 毫秒
11.
Francesco Traccis Valeria Serra Claudia Sagheddu Mauro Congiu Pierluigi Saba Gabriele Giua Paola Devoto Roberto Frau Joseph Francois Cheer Miriam Melis 《International journal of molecular sciences》2021,22(4)
Cannabis use among pregnant women is increasing worldwide along with permissive sociocultural attitudes toward it. Prenatal cannabis exposure (PCE), however, is associated with adverse outcome among offspring, ranging from reduced birth weight to child psychopathology. We have previously shown that male rat offspring prenatally exposed to Δ9-tetrahydrocannabinol (THC), a rat model of PCE, exhibit extensive molecular, cellular, and synaptic changes in dopamine neurons of the ventral tegmental area (VTA), resulting in a susceptible mesolimbic dopamine system associated with a psychotic-like endophenotype. This phenotype only reveals itself upon a single exposure to THC in males but not females. Here, we characterized the impact of PCE on female behaviors and mesolimbic dopamine system function by combining in vivo single-unit extracellular recordings in anesthetized animals and ex vivo patch clamp recordings, along with neurochemical and behavioral analyses. We find that PCE female offspring do not show any spontaneous or THC-induced behavioral disease-relevant phenotypes. The THC-induced increase in dopamine levels in nucleus accumbens was reduced in PCE female offspring, even when VTA dopamine activity in vivo and ex vivo did not differ compared to control. These findings indicate that PCE impacts mesolimbic dopamine function and its related behavioral domains in a sex-dependent manner and warrant further investigations to decipher the mechanisms determining this sex-related protective effect from intrauterine THC exposure. 相似文献
12.
13.
14.
Cesira Pasquarella Licia Veronesi Giorgio Liguori Christian Napoli Ida Torre Valeria Di Onofrio Carola Tinteri SItI working group "Hygiene in Dentistry 《The Science of the total environment》2010,408(19):4045-4051
The dental practice is associated with a high risk of infections, both for patients and healthcare operators, and the environment may play an important role in the transmission of infectious diseases. A microbiological environmental investigation was carried out in six dental clinics as a pilot study for a larger multicentre study that will be performed by the Italian SItI (Society of Hygiene, Preventive Medicine and Public Health) working group "Hygiene in Dentistry". Microbial contamination of water, air and surfaces was assessed in each clinic during the five working days of the week, before and during treatments. Air and surfaces were also examined at the end of the daily activity. A wide variation was found in microbial environmental contamination, both within the participating clinics and relative to the different sampling times. Microbial water contamination in Dental Unit Water Systems (DUWS) reached values of up to 26 × 104 cfu/mL (colony forming units per millilitre). P. aeruginosa was found in 33% of the sampled DUWS and Legionella spp. in 50%. A significant decrease in the Total Viable Count (TVC) was recorded during the activity. Microbial air contamination showed the highest levels during dental treatments and tended to decrease at the end of the working activity (p < 0.05). Microbial buildup on surfaces increased significantly during the working hours. As these findings point out, research on microbial environmental contamination and the related risk factors in dental clinics should be expanded and should also be based on larger collections of data, in order to provide the essential knowledge aimed at targeted preventive interventions. 相似文献
15.
Valeria Lingua 《Planning Perspectives》2018,33(4):591-614
ABSTRACTThis paper proposes approaching the emergence and evolution of the Europeanization of national planning using conceptual frameworks from historical institutionalism in order to shed light on the mechanisms and trajectories of domestic change arising from the influence of EU strategic planning. It seeks in particular to examine Europeanization in terms of the extent to which EU spatial planning has become a driving force for institutional changes in very different national planning systems. Returning to the changes that occurred in the Italian and English planning systems in the last two decades, the author provides insight into the attempts to insert and transpose EU spatial planning concepts and instruments into domestic systems, dealing with path dependency and European influence. By reading these processes from a historical institutionalist perspective, the paper aims to enhance understanding of the relative influence of European spatial planning on national planning systems, identifying mechanisms and trajectories of domestic change in different planning systems. Key findings concern the diverse modes and degree of institutionalization of EU strategic spatial planning, examining tendencies to replace the status quo through displacements in England and to progress through a path-dependent trajectory in Italy. 相似文献
16.
17.
Daniela dell'Oro Francesco Casamassima Giuseppe Gesualdo Marco Iammarino Paolo Mambelli Valeria Nardelli 《International Journal of Food Science & Technology》2014,49(5):1391-1400
The aim of this study was to develop and validate an efficient analytical method based on gas chromatography/tandem mass spectrometry (GC/MS/MS) for detection and quantification of six pyrethroids residues (Phenothrin, Permethrin, Cyfluthrin, Cypermethrin, Deltamethrin and Fenvalerate) in chicken eggs. The method was based on a preliminary liquid–liquid extraction of albumen‐free yolk samples, followed by a clean‐up by solid‐phase extraction. GC/MS/MS analyses were carried out in the selected reaction monitoring mode. Validation parameters such as specificity, detection capability, decision limit, precision, recovery, stability and ruggedness were determined, resulting in compliance with Decision 2002/657/EC. No complicated apparatus are required; moreover, low volumes of organic solvents and a nonintensive manual labour are required. These low costs and simple procedure, based on rapid and safe operations, may represent a useful tool in the routine analysis of pyrethroids pesticides, in the place of the currently used conventional techniques. 相似文献
18.
19.
20.
Sviatlana A. Ulasevich Anastasia V. Nenashkina Nikolai V. Ryzhkov Grigorii Kiselev Valeria Nikolaeva Aleksandra Kiseleva Kseniia Mosina Ekaterina V. Skorb Elena F. Krivoshapkina 《大分子材料与工程》2019,304(12)
Biodegradable implants are required in order to provide successful treatment of injuries. Temporary magnesium‐based implants with particular properties are needed in cases when it is desirable not only to maintain vital activity, but also to initiate the self‐healing process of damaged bones or tissues as well. Unfortunately, the use of magnesium alloys is limited due to the fast biodegradability of the applied material. The aim of this research is to improve the corrosion resistance of magnesium alloys by sonochemical treatment in silk solution followed by additional layer‐by‐layer deposition of natural silk on the magnesium surface. The sonication process is carried out at a frequency of 20 kHz during 5–10 min, while the duration of the silk layer deposition is 15 min. The corrosion behavior of magnesium substrates modified by natural silk layer‐by‐layer assembly is studied. Magnesium substrates sonochemically treated in silk solution demonstrate three times better corrosion resistance compared to control samples sonochemically treated in water. Additional deposition of a silk layer enhances obtained corrosion resistance by 18 times, resulting in a 54‐fold increase overall. 相似文献