全文获取类型
收费全文 | 19437篇 |
免费 | 1124篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 273篇 |
综合类 | 75篇 |
化学工业 | 4228篇 |
金属工艺 | 526篇 |
机械仪表 | 415篇 |
建筑科学 | 1142篇 |
矿业工程 | 71篇 |
能源动力 | 413篇 |
轻工业 | 2427篇 |
水利工程 | 163篇 |
石油天然气 | 57篇 |
武器工业 | 1篇 |
无线电 | 1379篇 |
一般工业技术 | 4199篇 |
冶金工业 | 1819篇 |
原子能技术 | 146篇 |
自动化技术 | 3240篇 |
出版年
2023年 | 198篇 |
2022年 | 222篇 |
2021年 | 514篇 |
2020年 | 329篇 |
2019年 | 342篇 |
2018年 | 605篇 |
2017年 | 575篇 |
2016年 | 696篇 |
2015年 | 519篇 |
2014年 | 705篇 |
2013年 | 1283篇 |
2012年 | 975篇 |
2011年 | 1185篇 |
2010年 | 885篇 |
2009年 | 955篇 |
2008年 | 987篇 |
2007年 | 888篇 |
2006年 | 708篇 |
2005年 | 583篇 |
2004年 | 525篇 |
2003年 | 512篇 |
2002年 | 419篇 |
2001年 | 357篇 |
2000年 | 306篇 |
1999年 | 288篇 |
1998年 | 590篇 |
1997年 | 416篇 |
1996年 | 348篇 |
1995年 | 229篇 |
1994年 | 236篇 |
1993年 | 213篇 |
1992年 | 120篇 |
1991年 | 143篇 |
1990年 | 112篇 |
1989年 | 148篇 |
1988年 | 93篇 |
1987年 | 114篇 |
1986年 | 122篇 |
1985年 | 182篇 |
1984年 | 148篇 |
1983年 | 116篇 |
1982年 | 115篇 |
1981年 | 93篇 |
1980年 | 96篇 |
1979年 | 90篇 |
1978年 | 84篇 |
1977年 | 85篇 |
1976年 | 142篇 |
1975年 | 78篇 |
1973年 | 78篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
111.
热等静压技术的发展及应用 总被引:9,自引:1,他引:8
在介绍热等静压技术和设备发展的基础上,对其在提高铸件质量以及拓展高速钢、双炼钢和超级双炼钢、高性能陶瓷等新型材料应用领域方面的作用,进行了较全面的阐述。并预计,因热等静压技术所具有的优势,在今后几年其应用增长可达到每年递增15%-20%的水平,且随着其在铝加工工艺中应用的拓展,年增长率可望达到25%。 相似文献
112.
113.
H.-U. Waiblinger N. Graf D. Mäde K. Woll U. Busch B. Holland H. Pilsl G. Naeumann R. Reiting B. Ehrentreich M. Schulze B. Tschirdewahn C. Brünen-Nieweler G. Hempel M. Weidner A. R. Winterstein 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2007,2(2):126-129
In case of findings of authorized genetically modified (gm) plant ingredients below the 0.9 per cent threshold, exceptions
from labelling requirements according to regulation (EC) No. 1829/2003 can only be made, “provided that this presence is adventitious
or technically unavoidable”. The authors describe factors that should be considered regarding contaminations by gm plant ingredients
as technically unavoidable or not. A practical approach for interpretation, taking into account quality control measures and
documentation as well as present findings in comparable products is proposed.
Received: February 23, 2007 相似文献
114.
Abderrafi M. Ougouag Jan Leen Kloosterman Wilfred F.G. van Rooijen Hans D. Gougar William K. Terry 《Nuclear Engineering and Design》2006,236(5-6):669-2004
Models and methods are presented for determining practical limits of the packing density of TRISO particles in fuel pebbles for a pebble-bed reactor (PBR). These models are devised for designing and interpreting fuel testing experiments. Two processes for particle failure are accounted for: failure of touching particles at the pressing stage in the pebble manufacturing process and failure due to inner pressure buildup during irradiation. The second process gains importance with increasing fuel temperature, which limits the particle packing density and the corresponding fuel enrichment. Suggestions for improvements to the models are presented. 相似文献
115.
E. Stenitzer H. Diestel Th. Zenker R. Schwartengräber 《Water Resources Management》2007,21(9):1567-1584
The performance of the water balance and crop growth model SIMWASER to estimate the water supply of a lawn by capillary rise
from shallow ground water was investigated by using lysimeter measurements with a sandy and a clayey soil. Moreover the robustness
of the model was evaluated by running it either with measured hydraulic soil parameters or with estimated pedotransfer functions
(PTFs) derived from texture and bulk density. Simulations were performed for the years 1996–1998 with input data from the
lysimeter station Berlin-Dahlem (Germany) for lysimeters containing undisturbed sandy or clayey soil monoliths, with groundwater
at 135 cm depth. Simulated evapotranspiration and percolation/capillary rise were in good agreement with the measured data
for all variants, while simulated soil water storage was acceptable only for the variants using hydraulic soil data based
on laboratory measurements or using PTFs derived from known soil class and bulk density. PTFs based on mean total pore volume
of the respective soil classes yielded soil water storages which were evidently too high; therefore they should be used with
care and must be avoided at all in simulating the soil water balance of arid sites with shallow groundwater. 相似文献
116.
117.
Kristof Brijs Filip Delvaux Viky Gilis Jan A. Delcour 《Journal of the Institute of Brewing》2002,108(3):348-354
Solubilisation and degradation of wheat gluten proteins by barley malt proteolytic enzymes (BMPE) was investigated with a model buffer system at pH 4.0 and pH 5.6, representing optimal pH for proteolysis and a pH value typical for beer brewing conditions respectively. Under the experimental conditions, incubation of commercial wheat gluten with BMPE solubilised 70% and 20% of the gluten proteins at pH 4.0 and pH 5.6 respectively. Gel permeation chromatography profiles and SDS‐PAGE showed that wheat gluten proteins were more degraded by BMPE at pH 4.0 than at pH 5.6. In a laboratory scale barley malt brewing experiment, proteins of worts, prepared with and without wheat gluten, were characterised. Results comparable to those in the model buffer system at pH 5.6 were obtained, which indicated that BMPE indeed solubilise wheat gluten during mashing, but that further degradation is rather limited under these conditions. 相似文献
118.
A. V. Räisänen W. R. McGrath D. G. Crete P. L. Richards 《Journal of Infrared, Millimeter and Terahertz Waves》1985,6(12):1169-1189
Several scaled models have been used to determine the contributions of various waveguide mount parameters to the embedding impedance of a mm-wave SIS mixer. Measured effects of waveguide height, substrate orientation and width, junction location, lead inductance and RF-filter impedance are presented and discussed. 相似文献
119.
We describe planar buried heterostructure lasers which have low capacitance (lpF), large bandwidth (19GHz), high power (>20mW/facet) and high temperature operation (100°C). These lasers are very suitable for long-distance, highspeed digital and analogue signal transmission. 相似文献
120.
Summary ESCA is used to characterize ion beam irradiated P(p-ClPhMA)-samples. The results show a chlorine abstraction. The experimental
findings are in accordance with a recently proposed model for a crosslinking mechanism of halogenated aromatic polymers. 相似文献