全文获取类型
收费全文 | 1930篇 |
免费 | 106篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 31篇 |
综合类 | 6篇 |
化学工业 | 417篇 |
金属工艺 | 41篇 |
机械仪表 | 90篇 |
建筑科学 | 62篇 |
矿业工程 | 4篇 |
能源动力 | 70篇 |
轻工业 | 133篇 |
水利工程 | 18篇 |
石油天然气 | 6篇 |
无线电 | 353篇 |
一般工业技术 | 325篇 |
冶金工业 | 153篇 |
原子能技术 | 11篇 |
自动化技术 | 322篇 |
出版年
2023年 | 44篇 |
2022年 | 49篇 |
2021年 | 103篇 |
2020年 | 83篇 |
2019年 | 76篇 |
2018年 | 98篇 |
2017年 | 61篇 |
2016年 | 128篇 |
2015年 | 51篇 |
2014年 | 86篇 |
2013年 | 127篇 |
2012年 | 94篇 |
2011年 | 91篇 |
2010年 | 85篇 |
2009年 | 85篇 |
2008年 | 72篇 |
2007年 | 72篇 |
2006年 | 57篇 |
2005年 | 36篇 |
2004年 | 39篇 |
2003年 | 38篇 |
2002年 | 36篇 |
2001年 | 28篇 |
2000年 | 18篇 |
1999年 | 28篇 |
1998年 | 61篇 |
1997年 | 42篇 |
1996年 | 20篇 |
1995年 | 30篇 |
1994年 | 25篇 |
1993年 | 31篇 |
1992年 | 25篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1973年 | 2篇 |
排序方式: 共有2042条查询结果,搜索用时 953 毫秒
91.
Applied Intelligence - Recommendation systems play an important role in boosting purchasing consumption for many manufacturers by helping consumers find the most appropriate items. Furthermore,... 相似文献
92.
Diem-Huong Nguyen Tran Thi Hiep Nguyen Thanh Nguyet Nguyen Vo Linh Phuong Tran Pham Do Minh Hoang Vo Cuu Khoa Nguyen Long Giang Bach Dai Hai Nguyen 《应用聚合物科学杂志》2019,136(20):47544
Curcumin (CUR) is a natural active ingredient that attracted much attention for its chemotherapeutic activity against tumors without causing toxicity in healthy cells. However, it has certain limitations for being used in chemotherapy such as low aqueous solubility and hydrolytic instability in the physiological environment. In this study, self-assembled poly(ethylene glycol) methyl ether-grafted gelatin (Gel-mPEG) nanogels were fabricated as delivery systems to improve the applicability of CUR in cancer treatment. CUR-loaded Gel-mPEG nanogels exhibited desired size range, relatively colloidal stability, and provided enhanced CUR stability in aqueous solutions. Especially, they showed significant high CUR loading capacity and better anticancer activity than free CUR as compared to previously reported CUR-loaded nanogels according to the best of our knowledge. Moreover, the in vitro release of CUR from the nanogels was controlled and prolonged up to 96 h. These results demonstrated that Gel-mPEG nanogels are the promising modality for the efficient delivery of CUR in cancer treatment. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47544. 相似文献
93.
An T. Nguyen Wei-Cheng Lai Van Viet Tran Duc Dung Nguyen Hung-Chih Kan 《Energy Materials: Materials Science and Engineering for Energy Systems》2016,11(2):23-29
Specific graphene architectures at the macroscopic scale are paramount for exploring new functions and practical uses of graphene. In this study, macroscopic, freestanding, and tubular graphene (TG) architectures were successfully fabricated through a versatile and robust process based on the annealing of cellulose acetate (CA) on Ni templates. These TG architectures can be obtained as woven tubes with diameters of approximately 50 μm; they possess high graphitic crystallinity, strong electrical conductivity, and favorable corrosion resistance. The effects of processing parameters, such as annealing temperature, annealing time, and amount of CA, on the graphene properties of these architectures were investigated and are discussed in this paper. The graphene properties were characterized through field emission scanning electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, Raman spectroscopy, four-point probe resistivity, and electrochemical measurements. 相似文献
94.
95.
Viet Hung Pham Thanh Truong Dang Tran Viet Cuong Seung Hyun Hur Byung-Seon Kong Eui Jung Kim Jin Suk Chung 《Korean Journal of Chemical Engineering》2012,29(5):680-685
We report the effect of temperature on the extent of graphene oxide reduction by hydrazine and the dispersibility of the resulting
chemically converted graphene (CCG) in polar organic solvents. The extent of graphene oxide reduction at high temperatures
was only slightly higher than at low temperatures (30–50 °C), while the dispersibility of the resulting CCG in organic solvents
decreased markedly with increasing temperature. The low dispersibility of CCGs prepared at high temperatures was greatly affected
by reduction and influenced by the formation of an irreversible agglomerate of CCG at high temperatures. The reduction of
graphene oxide at low temperatures is necessary to prepare highly dispersible CCG in organic solvents. CCG prepared at 30
°C is dispersible in N-methyl-2-pyrrolidone concentrations as high as 0.71 mg/mL. The free-standing paper made of this CCG
possessed an electrical conductivity of more than 22,000 S/m, one of the highest values ever reported. 相似文献
96.
Abstract Phase properties of a coherent field interacting with a two-level atom in an ideal cavity are studied using the new hermitian phase formalism of Pegg and Barnett. It is shown in particular that phase properties of the field reflect the collapse and revival phenomena. The effects of finite detuning and atomic coherences are treated. The results for the variance of the phase cosine are obtained and compared with those based on earlier approaches. 相似文献
97.
98.
Bulk ultrafine-grained nickel specimens having grain sizes in the range of 0.25-5 μm were consolidated by hot isostatic pressing technique. The resulting microstructures were characterized by transmission electron microscopy and X-ray diffraction analysis. Compression tests were carried out at room temperature and at strain rate of 1.6×10−4 s−1. It was found that the measured yield strength does not follow the Hall-Petch law as a consequence of the presence of oxide phase. Therefore, the use of micromechanics based model, which takes into account only the Hall-Petch relationship at grain level for predicting the grain sized effects on mechanical behavior of this kind of materials, is not accurate yet. In this study, a modification made to the generalized self-consistent model was proposed for studying both grain size and oxide phase dependence of ultrafine-grained materials behavior. Because of the novel modification, an optimization procedure with two steps was required to identify the parameters of micromechanical model. An acceptable agreement between experimental and numerical results was achieved. Moreover, the influence of texture on the yield strength and the application of the proposed model to the spark plasma sintering processed materials were also discussed. 相似文献
99.
D. T. Pham I. A. Nicholas 《International Journal of Adaptive Control and Signal Processing》2001,15(8):865-881
Low‐temperature desulphurization (LTD) is a low‐cost alternative to conventional wet scrubbing for removing sulphur dioxide from flue gas produced by power generating plants. A problem in the design of conventional controllers to achieve and maintain process conditions for optimal desulphurisation is the lack of mathematical models to characterise the complex desulphurization process and unexpected environ mental disturbances. The aim of the work reported in this paper was to replace a skilled human operator who could successfully regulate the LTD plant through manipulation of low‐level controllers with a competitive neurofuzzy system, which possesses both the learning ability of neural networks and the structural transparency of fuzzy logic systems. A hierarchical control structure was adopted whereby the competitive neurofuzzy method was used at the top level for co‐ordinating actions of low‐level conventional controllers. This approach would considerably simplify the task of designing the control system and has been shown to yield high‐level controllers with performances at least equalling that of expert operators, as demonstrated in this paper. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
100.
Hai Pham 《Water research》2009,43(11):2936-8451
1,2-Dichloroethane (1,2-DCA) is a well-known recalcitrant groundwater contaminant. New environment-friendly approaches for the removal of 1,2-DCA that does not bring about volatilization of the compound are required. In this study, different anodophilic consortia enriched in microbial fuel cells (MFCs) operated under airtight conditions were shown to effectively degrade 1,2-DCA (up to 102 mg per liter reactor volume per day), while concomitantly generating a current. An anodophilic consortium previously enriched with acetate as the electron donor changed its composition at the rate of 48% per week and increased its richness (Rr) 3-fold, upon adapting to 1,2-DCA as the new electron donor. After being stable, during 1 month of operation, it removed up to 95% of the 1,2-DCA amount in the medium in the first 2 weeks, while converting 43 ± 4% of electrons available from the removal to electricity. A natural consortium from a 1,2-DCA contaminated site changed its composition at the rate of 9% per week and increased its Rr 2-fold, upon adapting to the MFC anode conditions with 1,2-DCA as the electron donor. After being stable, during 1 month of operation, it removed up to 85% of the 1,2-DCA amount in the medium in the first 2 weeks and the coulombic efficiency was 25 ± 4%. The operation of the MFCs under closed circuit conditions resulted in higher 1,2-DCA removal rates than the operation under open circuit conditions, indicating that bioelectrochemical activities enhanced the removal of 1,2-DCA in the MFC anode. The production of ethylene glycol, acetate and carbon dioxide indicated that the anodophilic bacteria oxidatively metabolized 1,2-DCA, probably by means of a hydrolysis-based pathway. The results show that MFCs can be potentially used as a practically convenient technology for the biological removal of 1,2-DCA. 相似文献