全文获取类型
收费全文 | 1828篇 |
免费 | 100篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 29篇 |
化学工业 | 425篇 |
金属工艺 | 11篇 |
机械仪表 | 41篇 |
建筑科学 | 76篇 |
矿业工程 | 1篇 |
能源动力 | 41篇 |
轻工业 | 184篇 |
水利工程 | 28篇 |
石油天然气 | 2篇 |
无线电 | 165篇 |
一般工业技术 | 354篇 |
冶金工业 | 224篇 |
原子能技术 | 20篇 |
自动化技术 | 330篇 |
出版年
2023年 | 11篇 |
2022年 | 97篇 |
2021年 | 102篇 |
2020年 | 60篇 |
2019年 | 51篇 |
2018年 | 63篇 |
2017年 | 44篇 |
2016年 | 67篇 |
2015年 | 47篇 |
2014年 | 64篇 |
2013年 | 104篇 |
2012年 | 100篇 |
2011年 | 133篇 |
2010年 | 81篇 |
2009年 | 89篇 |
2008年 | 93篇 |
2007年 | 82篇 |
2006年 | 64篇 |
2005年 | 60篇 |
2004年 | 48篇 |
2003年 | 36篇 |
2002年 | 37篇 |
2001年 | 27篇 |
2000年 | 17篇 |
1999年 | 25篇 |
1998年 | 56篇 |
1997年 | 46篇 |
1996年 | 26篇 |
1995年 | 16篇 |
1994年 | 14篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有1931条查询结果,搜索用时 31 毫秒
121.
Human computer interaction (HCI) has little explored everyday life and enriching experiences in rural, wilderness and other
predominantly “natural” places despite their socioeconomic importance. Beyond simply addressing the challenge arising from
applying an urban perspective to designing technologies for use in natural places, we wish to provoke integration of the natural
and computational worlds. To stimulate design that both draws upon and affords such integration, we propose seven themes we
have distilled from the literature and supplement these with our own research observations. Bodies Imagine and Remember recognizes
the inseparability of meanings and corporeal experience of natural places for design. Indexicality and Habitus refers to the
need for design to be sensitive to the processes by which natural features become intelligible in our actions and communication.
Values and Story-spaces observes the way representations and infrastructures, infused with particular values, become dominant.
Identity and Belonging, suggests the need to reconcile designs with couplings between physical settings, processes of community
and personal identity. Rhythm and Dynamism considers links between people’s daily routines, nature’s events and patterns and
spatial and social issues pertinent to design and in Revealing and Receding we suggest that design must simultaneously fade
into the background and provoke seeing natural places differently. Fragility, Liability and Spirituality refers to technological
opportunities to support positive relations within ecosystems and recognizing the limits of technological control. 相似文献
122.
123.
In this paper, the Causal Recursive Back-Propagation (CRBP) algorithm is employed to train on-line an Infinite Impulse Response–Locally Recurrent Neural Network (IIR–LRNN) for modelling the dynamics of a next-generation nuclear reactor. The results demonstrate the advantages of the on-line training over the batch-mode learning in the reconstruction of complex nonlinear dynamic relationships. 相似文献
124.
125.
In this work, we propose an index that allows a public authority to order different projects for the construction of onshore wind energy plants and that explicitly takes into account their environmental quality. Wind farm projects are defined as vectors of four attributes: the technical properties of each project, its social impact, its environmental impact, and the share of earnings that proponents offer to the collectivity in compensation for the negative externalities of the wind plant. We define an absolute index that allows the ordering of different proposals and evaluation of the acceptability of each project, providing the monetary value of each point and inducing a truthful revelation of firms' private information. Moreover, we calibrate the index on the basis of data referring to wind plants in Southern Italy and derive the corresponding iso-scoring curves. 相似文献
126.
127.
Bac V. Nguyen Qi Guang Wang Nicola J. Kuiper Alicia J. El Haj Colin R. Thomas Zhibing Zhang 《Journal of the Royal Society Interface》2010,7(53):1723-1733
A chondrocyte and its surrounding pericellular matrix (PCM) are defined as a chondron. Single chondrocytes and chondrons isolated from bovine articular cartilage were compressed by micromanipulation between two parallel surfaces in order to investigate their biomechanical properties and to discover the mechanical significance of the PCM. The force imposed on the cells was measured directly during compression to various deformations and then holding. When the nominal strain at the end of compression was 50 per cent, force relaxation showed that the cells were viscoelastic, but this viscoelasticity was generally insignificant when the nominal strain was 30 per cent or lower. The viscoelastic behaviour might be due to the mechanical response of the cell cytoskeleton and/or nucleus at higher deformations. A finite-element analysis was applied to simulate the experimental force-displacement/time data and to obtain mechanical property parameters of the chondrocytes and chondrons. Because of the large strains in the cells, a nonlinear elastic model was used for simulations of compression to 30 per cent nominal strain and a nonlinear viscoelastic model for 50 per cent. The elastic model yielded a Young''s modulus of 14 ± 1 kPa (mean ± s.e.) for chondrocytes and 19 ± 2 kPa for chondrons, respectively. The viscoelastic model generated an instantaneous elastic modulus of 21 ± 3 and 27 ± 4 kPa, a long-term modulus of 9.3 ± 0.8 and 12 ± 1 kPa and an apparent viscosity of 2.8 ± 0.5 and 3.4 ± 0.6 kPa s for chondrocytes and chondrons, respectively. It was concluded that chondrons were generally stiffer and showed less viscoelastic behaviour than chondrocytes, and that the PCM significantly influenced the mechanical properties of the cells. 相似文献
128.
Sensitive ground-fault protection refers to the concept of detecting low levels of ground-fault current that might cause electrocution of any human that becomes part of the ground-current path and providing warnings. The concepts behind sensitive ground-fault relaying for use on AC and DC low-voltage utilization systems are covered. The background for these relaying types is presented, and it is shown that the critical component in sensitive ground-fault relay design is the current sensor. Zero-sequence devices for three-phase industrial utilization systems and a saturable-transformer device for DC utilization are discussed. Relaying schemes for both AC and DC systems are presented. This study is aimed at mine power systems but could be applicable to any portable low-voltage portion of industrial power systems that involve handling by personnel 相似文献
129.
Meharg AA Pain DJ Ellam RM Baos R Olive V Joyson A Powell N Green AJ Hiraldo F 《The Science of the total environment》2002,300(1-3):81-86
White storks (Ciconia ciconia) fed in contaminated waters resulting from the Aznacollar acid mining-sludge spillage into the R. Guadiamar, which feeds the eastern flank of the Guadalquivir marshes (Do?ana), S.W. Spain. The sludge was rich in a range of toxic elements, and in organic pollutants such as the aromatic amines. Storks did not exhibit elevated metals in their blood immediately following the accident, but chick blood collected the year following the accident showed genotoxic damage compared to the controls. In this study lead isotope analysis was used to assess if the storks had ingested sludge-derived contaminants. The sludge lead isotope ratio was distinct from that of the Do?ana sediments. The stork blood lead isotope ratios exactly matched that of the sludge. It was concluded that the storks had ingested sludge-derived contaminants. A detailed study of the lead contamination along the R. Guadiamar and the R. Guadalquivir (of which the Guadiamar is a tributary) was also conducted to place the white stork colony lead exposure in the context of the spatial contamination of the storks' habitat. 相似文献
130.
Using survival analysis to investigate the effect of UV-C and heat treatment on storage rot of strawberry and sweet cherry 总被引:8,自引:0,他引:8
Marquenie D Michiels CW Geeraerd AH Schenk A Soontjen C Van Impe JF Nicolaï BM 《International journal of food microbiology》2002,73(2-3):187-196
Ultraviolet light and heat treatment are proposed as alternative techniques for the use of chemicals to reduce the development of the spoilage fungi Botrytis cinerea and Monilinia fructigena on strawberry and sweet cherry, respectively, during storage. In order to investigate the effect of both physical techniques on microbial inactivation and on fruit quality, inoculated berries were subjected to different temperatures (40-48 degrees C) and UV-C doses (0.05-1.50 J/cm2). For each condition, 20 berries were used. After the treatment, fungal growth, visual damage (holes, stains) and fruit firmness were evaluated during a period of 10 days. The experimental data were analysed statistically using survival analysis techniques. Fungal growth on strawberries was significantly retarded using UV-C doses of 0.05 J/cm2 and higher. The same treatment had no significant effect when applied to cherries. The highest doses (1.00 and 1.50 J/cm2) had a negative effect on the calyx of the strawberry, causing browning and drying of the leaves. No beneficial effect of a low temperature treatment (40-48 degrees C) on the shelf life of strawberries was observed, but fungal development on cherries was retarded at temperatures of 45 and 48 degrees C. These temperatures caused severe damage on strawberries (soft stains, holes, decreased firmness), but had no influence on the quality of sweet cherries. 相似文献