全文获取类型
收费全文 | 154篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 3篇 |
综合类 | 5篇 |
化学工业 | 8篇 |
金属工艺 | 1篇 |
机械仪表 | 6篇 |
建筑科学 | 9篇 |
矿业工程 | 4篇 |
轻工业 | 128篇 |
水利工程 | 1篇 |
无线电 | 1篇 |
一般工业技术 | 9篇 |
冶金工业 | 3篇 |
原子能技术 | 1篇 |
自动化技术 | 6篇 |
出版年
2024年 | 7篇 |
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 15篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 15篇 |
2012年 | 14篇 |
2011年 | 12篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有185条查询结果,搜索用时 15 毫秒
1.
Andrey N. Sharov Nadezhda A. Berezina Aleksey V. Tolstikov 《Lakes & Reservoirs: Research and Management》2015,20(2):120-127
This study focuses on hydrological and biotic variables in Lake Glubokoe, which is located in Thala Hills of Enderby Land (East Antarctica). Water and sediment samples and physical measurements were collected once a week in the austral summer (19 December 2010 – 6 February 2011). This lake exhibits perennial ice cover that reached a thickness of 2.5–2.7 m during the study period. A very low concentration of planktonic chlorophyll‐a (0.06–0.45 μg L?1) was measured in the lake, indicating its ultra‐oligotrophic status. The water was poorly populated by algae and metazoans, especially in upper waters below ice cover to a depth of 2 m. Small planktonic organisms (2–5 μm) were observed throughout the study period, but larger organisms (>8 μm) such as the cyanobacteria Planktolyngbya limnetica occurred only during the warmest period (January). Only few individuals of metazoans (rotifers) were found in planktonic samples. Due to deep light penetration (10–15% of incoming active solar radiation reached the depth of 30 m), thick cyanobacterial mats (30 cm) cover all the bottom surface (grey silts) in the lake. Abundant benthic biota associated with these mats was found (up to 1000 ind. m?2). Among the benthic metazoans, bdelloid rotifers and tardigrades were the dominating taxa. The results of this study suggest a typical ecological feature of most subglacial lakes in East Antarctica is that metazoans are very poor in the pelagic zone, preferring instead to occupy an area near the lake bottom because of a favourable constant temperature of 4 °C, good level of dissolved oxygen and available food resources as the bacterial detritus. 相似文献
2.
Antarctic scientific expedition has important strategic significance. It is an inevitable trend to apply robots to assist researchers during the Antarctic expedition. However, the robot manipula- tors at present have a series of problems and unable to meet the requirements of the Antarctic expe- dition. In this paper, a novel Antarctic modular robot manipulator is proposed, which has a compact structure with modular joints. The robot manipulator has high reliability, and quick assembling-and- disassembling ability. Through well wires arranging and thermal controlling, the manipulator can better adapt to the Antarctic environment. In addition, the work space of the manipulator is serious- ly analyzed, and a new hybrid position/force control method is adopted to make the manipulator per- form better. Simulation results validate the control method and show that the robot manipulator has a good performance to meet the requirements of Antarctic expedition. 相似文献
3.
目的 探究南极磷虾粉的真空干燥特性及其营养品质变化规律。方法 将磷虾原料在不同真空度(0.04、0.06、0.08 MPa)及温度(75、85、95 ℃)下进行真空干燥。通过测定干基含水率、干燥速率及水分扩散系数,研究其干燥特性。通过测定虾青素含量、TBA和色差,探究其营养品质的差异。结果 在75 ℃下,采用真空度0.06 MPa和0.08 MPa相较于0.04 MPa,其干燥时间分别缩短了15%、21%。在不同真空干燥条件下,磷虾有效水分扩散系数在(3.555 77~6.574 12)×10−10 m2/s之间,Midilli 模型预测值与实验值之间具有较高的拟合度(R2>0.999),能较准确地反映虾粉真空干燥过程。提高真空度可显著抑制虾青素的分解及脂肪氧化,在75 ℃条件下,采用真空度0.06 MPa和0.08 MPa相较于0.04 MPa,其虾青素含量分别提高了21%、48%。在95 ℃条件下,采用真空度0.08 MPa相较于0.04 MPa,其TBA值降低了47%。L*、a*受到温度的影响更明显,在同一温度下∆E随着真空度的上升而降低。结论 在0.08 MPa、75 ℃下,通过真空干燥可以有效抑制虾粉中活性物质的降解,同时保证干燥速率,此研究为南极磷虾粉的真空干燥工艺设计及生产控制提供了理论参考。 相似文献
4.
镜筒是望远镜的基本组成部分,为了能够更好的满足望远镜成像质量的要求,需要对望远镜的镜筒机械结构进行研究。南极巡天望远镜由于其特殊的地理位置及气候、温度条件限制,与普通的望远镜在镜筒上有不同的要求。首先介绍了第二台南极巡天望远镜的光学设计参数及方案,并根据南极的特殊性设计了镜筒的机械结构。其次,通过有限元的分析方法,对望远镜镜筒的等弯沉量、主镜的面形变化进行了分析和计算,使其在工作状态时能满足光学设计的要求,第三,通过模态分析,分析了镜筒的刚度,使其满足电控系统的控制要求,最后通过锤击实验对镜筒的自振频率做了检验检测。经过实验分析,第二台南极巡天望远镜的镜筒能够满足光学的设计要求。 相似文献
5.
6.
Elemental and mineral characterisation of Coastal Antarctic Aerosols in snow using PIXE and SEM-EDAX
Grazia Ghermandi Paolo Laj Margherita Capotosto Rodolfo Cecchi Carlo Riontino 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1999,150(1-4):392-397
The chemical constituents of snow from a 3 m pit sampled at a coastal Antarctic site were characterised by means of PIXE and SEM-EDAX. Oxygen isotope dating revealed that the pit spanned an 8-year period, from 1986 to 1994. Concentrations measured by PIXE ranged from less than 1 ng g−1 of H2O for Cu, and Zn to several tens of ng g−1 for Si, S and Cl. The major elements found were Si, S, Al, and Na, which contributed more than 75% of the element loading. Snow layers with elevated Cl concentration were regularly found along the pit. The mineralogy of the insoluble particles determined by SEM-EDAX analyses showed that quartz, plagioclase and clays were the prevalent minerals. The proportion of each element in the insoluble phase was comparable with that previously found in similar studies. 相似文献
7.
UV-B辐射对南极冰藻中抗辐射物质的诱导作用 总被引:18,自引:0,他引:18
在人工UV-B辐照下培养5种南极冰藻,其中包括三种硅藻:H1硅藻(diatom H1),H2硅藻(diatom H2),H3硅藻(diatom H3),两种绿藻:L1绿藻(Pyramimonas sp.),L4绿藻(Chlorophyceae)。研究了UV-B辐射对南极冰藻中抗辐射物质的诱导作用。这些物质被认为具有抵抗UV-B辐射损害而提供保护的作用。结果表明,(1)UV-B辐射诱导产生大量的胞内多糖和胞外多糖物质,胞外多糖附着藻体;(2)UV-B辐射诱导产生新的水溶性色素类物质;(3)UV-B辐射诱导产生新的脂溶性色素类物质,不同种类冰藻产生的新色素的最大吸收峰不同,这些结果使我们初步认识了南极冰藻对南极强辐射环境的适应机理,并为进一步利用UV-B辐射培养南极冰藻产生抗辐射.抗肿瘤、清除自由基等新型活性物质提供依据。 相似文献
8.
9.
10.
目的:研究补充南极磷虾油(krill oil,KO)对小鼠一次性力竭运动后骨骼肌质膜损伤和功能恢复的影响,探讨补充南极磷虾油促进骨骼肌质膜损伤修复的可能机制。方法:选取8周龄雄性C57小鼠60只,随机分为豆油对照(bean oil control,BOC)组、豆油运动(bean oil exercise,BOE)组、磷虾油对照(krill oil control,KOC)组和磷虾油运动(krill oil exercise,KOE)组,KO组连续灌胃4周200 mg/(kg mb·d)磷虾油,豆油组进行等体积豆油灌胃。干预4周后,运动组进行一次性力竭跑台运动,每组6只小鼠在力竭运动后即刻(0 h)、2、6、24、48、72 h进行抓力测试,其余小鼠于运动后2 h取材。比色法检测小鼠血清肌酸激酶(creatine kinase,CK)、乳酸脱氢酶(lactate dehydrogenase,LDH)活力;冰冻切片并采用伊文氏蓝(Evan’s blue dye,EBD)染色法检测小鼠股四头肌质膜完整性;液相色谱-质谱法检测小鼠股四头肌质膜脂肪酸成分;荧光偏振法检测小鼠... 相似文献