全文获取类型
收费全文 | 683篇 |
免费 | 28篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 295篇 |
金属工艺 | 9篇 |
机械仪表 | 8篇 |
建筑科学 | 15篇 |
矿业工程 | 4篇 |
能源动力 | 28篇 |
轻工业 | 60篇 |
水利工程 | 6篇 |
石油天然气 | 13篇 |
无线电 | 25篇 |
一般工业技术 | 164篇 |
冶金工业 | 21篇 |
原子能技术 | 1篇 |
自动化技术 | 65篇 |
出版年
2024年 | 4篇 |
2023年 | 11篇 |
2022年 | 84篇 |
2021年 | 74篇 |
2020年 | 14篇 |
2019年 | 19篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 40篇 |
2015年 | 18篇 |
2014年 | 37篇 |
2013年 | 52篇 |
2012年 | 43篇 |
2011年 | 45篇 |
2010年 | 24篇 |
2009年 | 31篇 |
2008年 | 31篇 |
2007年 | 23篇 |
2006年 | 20篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 14篇 |
2002年 | 18篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有717条查询结果,搜索用时 15 毫秒
51.
In countries with unstable conditions, negotiations regarding construction work takes place under conditions of great uncertainty with both sides, the purchaser and the investor, trying to minimize the difficulties. This paper gives an insight of how matters relating to costing are looked at by professionals when faced with such conditions. 相似文献
52.
David G. McIntyre Shawn J. Cunningham Judd S. Carper Paul D. Jaramillo Svetlana Tatic-Lucic Larry E. Starr 《Sensors and actuators. A, Physical》1997,60(1-3):181-185
Single-crystal silicon microstructures, of identical design, exhibit different failure rates (following fabrication or mechanical shock testing) due to various processes. The microstructures fabricated with a boron diffusion and subsequent removal of the boron-diffused layer have a higher survival rate to the fabrication process and to mechanical shock. The survival rate (a survivor has an intact proof mass and beam) through the process is increased by 26.5%. At a 3680g shock, the boron-diffused devices have a 2.3% lower failure rate but the difference is not statistically significant. These results have been developed with wafer-level shock testing, which permits bulk testing of many samples in a cost-effective manner. 相似文献
53.
Jovanović I Ugrenović S Antić S Stefanović N Mihailović D 《Microscopy research and technique》2007,70(7):617-627
Psammoma bodies (PBs) are one of many choroids plexus aging changes. The aim of our research was to perform the quantification of PBs' presence in human choroids plexus stroma, as well as to evaluate the characteristics of choroids plexus stroma in cases in which PBs were present. Afterwards, the observations of the histochemical analysis would be confirmed by immunohistochemical analysis. Choroid plexuses of 30 cadavers were used for the histochemical and, choroids plexuses of 15 cadavers in which PBs' presence was confirmed during the histochemical analysis, were used as material for the immunohistochemical analysis. Light microscopy, histochemical, immunohistochemical, and morphometric method were applied during the study. Classification of the cases was performed by cluster analysis. We observed increase of choroids plexus PBs' presence during the aging process. But this increase is not linear. Their presence is the largest in the second cluster that is younger than the third and older than the first. Nuclear morphometric parameters of the stroma in these cases showed that the cellular composition in this cluster is different than in other two and, that contain larger number of lymphoid cells. Immunohistochemical analysis showed PBs' positive reaction on vimentin, CD45R0, and LCA markers, while in their vicinity, as well as inside them, numerous T-cells were observed. So, the presence of CD45R0 and LCA-positive T cells, PBs' positive reaction on the same markers, indirectly connect these cells with PBs' formation process. 相似文献
54.
Magdalen Zlatanov Ginka Antova Maria Angelova-Romova Svetlana Momchilova Sabina Taneva Boryana Nikolova-Damyanova 《Journal of the American Oil Chemists' Society》2012,89(8):1393-1401
The lipid composition of the seed oil of three varieties (L-74, VIR-11 and BGR-455) of Lallemantia iberica Fisch. &; Mey. (Lamiaceae) harvested in Bulgaria was examined in detail. Triacylglycerols (TAG >90%), phospholipids (<3%), sterol esters (~0.2%), and accompanying compounds—sterols (~0.3%) and tocopherols (336–499 mg/kg)—were determined for the first time. In addition, the specific distribution of fatty acids between the lipid classes was elucidated. Nineteen TAG species were unambiguously identified and quantified and of these the highly unsaturated trilinolenin, dilinolenyl linoleate and dilinolenyl palmitate comprised 59% of the total TAG. Phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine were the main phospholipids. Beta-sitosterol was the main sterol component, followed by campesterol and stigmasterol. Gamma-tocopherol predominated (>90%) in the tocopherol fraction. Palmitic acid (16:0) was the major fatty acid of the phospholipids and oleic acid (cis 9-18:1) dominated in the sterol ester fraction. The three varieties have similar lipid compositions with BGR-455 being slightly more saturated. Due to its composition, Lallemantia oil might compete successfully with flax and other plant oils as a source of linolenic fatty acid in industrial and dietary applications. 相似文献
55.
Maria O. Ilatovskaya Roman V. Starykh Svetlana I. Sinyova 《Metallurgical and Materials Transactions B》2014,45(5):1757-1768
Phase equilibria of the ternary Cu-Co-S system were studied within liquidus–solidus temperature range in the inert atmosphere at atmospheric pressure. Integrated application of such methods as differential thermal analysis, thermogravimetry, scanning electron microscopy, and electron probe microanalysis, makes it possible to determine phase transitions temperature and equilibrium phases composition in the system with high level of accuracy. Experimental results obtained in this work for the Cu-Co-S system are presented as liquidus and solidus surfaces projections of the Cu-Co-S system. Phase transformations occurring in the system are discussed. 相似文献
56.
Makarova TL Shelankov AL Lyubchik SB Serenkov IT Sakharov VI 《Journal of nanoscience and nanotechnology》2012,12(6):5051-5053
Irradiation with helium ions is an effective method for triggering ferromagnetism in graphite. Chemical inertness of helium suggests that local magnetic moment formation is determined solely by the intrinsic carbon defects created during the target damage. Interacting moments are located in two places: in the vicinity of the sample surface and near the point of maximum defect generation. 相似文献
57.
Gaoshan Jing Wenyue Zhang Shi-Fang Lu Svetlana Tatic-Lucic 《Microelectronic Engineering》2009,86(11):2334-2341
In this paper, we describe the development of microcontact printing stamps from photopatternable silicone. The photopatternability of this material enables convenient and fast stamp fabrication, and allows rapid patterning of substrates for culturing biological cells. Microcontact printing stamps made of the photopatternable silicone with linewidths as small as 2 μm were fabricated and reliable cell patterning results were obtained by optimizing the stamping process. An optimal stamp surface was obtained by optimizing the photolithographic process. Our successful demonstration of patterning cells using the photopatternable silicone stamps establishes this alternative approach for fabricating microcontact printing stamps. 相似文献
58.
59.
60.
Yuriy Zakrevskyy Marcel Richter Svitlana Zakrevska Nino Lomadze Regine von Klitzing Svetlana Santer 《Advanced functional materials》2012,22(23):5000-5009
The light‐induced reversible switching of the swelling of microgel particles triggered by photo‐isomerization and binding/unbinding of a photosensitive azobenzene‐containing surfactant is reported. The interactions between the microgel (N‐isopropylacrylamide, co‐monomer: allyl acetic acid, crosslinker: N,N′‐methylenebisacrylamide) and the surfactant are studied by UV‐Vis spectroscopy, dynamic and electrophoretic light scattering measurements. Addition of the surfactant above a critical concentration leads to contraction/collapse of the microgel. UV light irradiation results in trans‐cis isomerization of the azobenzene unit incorporated into the surfactant tail and causes an unbinding of the more hydrophilic cis isomer from the microgel and its reversible swelling. The reversible contraction can be realized by blue light irradiation that transfers the surfactant back to the more hydrophobic trans conformation, in which it binds to the microgel. The phase diagram of the surfactant‐microgel interaction and transitions (aggregation, contraction, and precipitation) is constructed and allows prediction of changes in the system when the concentration of one or both components is varied. Remote and reversible switching between different states can be realized by either UV or visible light irradiation. 相似文献