全文获取类型
收费全文 | 1646篇 |
免费 | 91篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 10篇 |
综合类 | 1篇 |
化学工业 | 522篇 |
金属工艺 | 24篇 |
机械仪表 | 19篇 |
建筑科学 | 56篇 |
矿业工程 | 6篇 |
能源动力 | 33篇 |
轻工业 | 317篇 |
水利工程 | 14篇 |
无线电 | 68篇 |
一般工业技术 | 231篇 |
冶金工业 | 228篇 |
原子能技术 | 8篇 |
自动化技术 | 201篇 |
出版年
2023年 | 19篇 |
2022年 | 110篇 |
2021年 | 95篇 |
2020年 | 46篇 |
2019年 | 36篇 |
2018年 | 49篇 |
2017年 | 42篇 |
2016年 | 66篇 |
2015年 | 31篇 |
2014年 | 81篇 |
2013年 | 104篇 |
2012年 | 94篇 |
2011年 | 126篇 |
2010年 | 105篇 |
2009年 | 84篇 |
2008年 | 83篇 |
2007年 | 69篇 |
2006年 | 45篇 |
2005年 | 50篇 |
2004年 | 28篇 |
2003年 | 37篇 |
2002年 | 26篇 |
2001年 | 14篇 |
2000年 | 29篇 |
1999年 | 25篇 |
1998年 | 32篇 |
1997年 | 40篇 |
1996年 | 21篇 |
1995年 | 17篇 |
1994年 | 15篇 |
1993年 | 21篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1966年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1738条查询结果,搜索用时 15 毫秒
31.
The introduction of residual surface stresses into a material can change the strength distribution simply due to variability in the stress intensity factor of surface cracks. This variability arises from the distribution in surface (critical) crack lengths. A fracture mechanics approach was used to determine the influence of surface compression on the average strength and the standard deviation of the strength distribution. The strengths of the stress-free samples were assumed to fit a twoparameter Weibull distribution, and the increases in strength resulting from the surface compression were determined using fracture mechanics. It was determined from the analysis that the standard deviation/average strength ratio (coefficient of variation) initially increases, passes through a maximum, and ultimately reaches a plateau value below the initial value, as one increases the depth of surface compression. The maximum increase in the strength scatter occurs when the depth of the surface compression is approximately equal to the characteristic crack size. These changes were found to be dependent on the magnitude of the surface stress, as well as the characteristic strength, Weibull modulus, and fracture toughness of the stress-free material. 相似文献
32.
Cibrian Franceli L. Ley-Flores Judith Newbold Joseph W. Singh Aneesha Bianchi-Berthouze Nadia Tentori Monica 《Personal and Ubiquitous Computing》2021,25(2):391-410
Personal and Ubiquitous Computing - Interactive sonification is an effective tool used to guide individuals when practicing movements. Little research has shown the use of interactive sonification... 相似文献
33.
Job Mwamburi George Basweti Monica Owili Jared Babu Peter Wawiye 《Lakes & Reservoirs: Research and Management》2020,25(3):292-313
Many large lake ecosystems are experiencing increasing eutrophication and persistent cyanobacteria‐dominated algal blooms affecting their water quality and ecosystem productivity because of widespread non‐point and point nutrient sources. Accordingly, the present study utilized data of July 2003 and January–February 2004, as well as previous measurements of nutrients and physico‐chemical variables (electrical conductivity, dissolved oxygen, temperature, pH, turbidity and chlorophyll‐a), to characterize the spatial and temporal trends, as a means of better understanding the factors influencing lake environmental conditions, as support tools for long‐term ecosystem management and for better understanding the long‐term trends and effects. Inshore gulf areas were found to represent zones of maximum nutrient concentrations, compared to the deep main lake zones, with significant inter‐parameter correlations. Phosphorus, silicon and chlorophyll‐a concentrations were significantly correlated. Water electrical conductivity was also significantly and positively correlated with soluble reactive silicon (SRSi), alkalinity hardness DO, while exhibiting a negative association with water transparency. Water turbidity and transparency, electrical conductivity, and SRSi concentrations clearly describe a gradient from the gulf into the main lake. For such a shallow gulf, these findings suggest primary productivity is influenced mainly by the availability of nutrients, light transparency and the extent of availability of resuspended nutrients. The increasing eutrophic state of Lake Victoria is a serious concern since it contributes to an increased potential of more frequent occurrences of cyanobacterial blooms, a potential public health risk to both humans and wildlife. Improved understanding of influences from previous fish species introductions and concomitant changes in indigenous fish species, increased lake basin population and anthropogenic activities, water hyacinth resurgences, sustainability of biodiversity, and current interests in cage farming, are among the major concerns and challenges facing the contemporary Lake Victoria. The trends regarding nutrients and physico‐chemical characteristics are intended to support better monitoring efforts and data to promote the lake's ecosystem services and the sustainable management of the lake ecosystem. 相似文献
34.
W. G. Vermeulen P. J. van der Wolk A. P. de Weijer S. van der Zwaag 《Journal of Materials Engineering and Performance》1996,5(1):57-63
Jominy hardness profiles of steels were predicted from chemical composition and austenitizing temperature using an artificial
neural network. The neural network was trained using some 4000 examples, covering a wide range of steel compositions. The
performance of the neural network is examined as a function of the network architecture, the number of alloying elements,
and the number of data sets used for training. A well-trained network predicts the Jominy hardness profile with an average
error of about 2 HRC. Special attention was devoted to the effect of boron on hardenability. A network trained using data
only from boron steels produced results similar to those of a network trained using all data available. The accuracy of the
predictions of the model is compared with that of an analytical model for hardenability and with that of a partial least-
squares model using the same set of data. 相似文献
35.
Gil Francopoulo Nuria Bel Monte George Nicoletta Calzolari Monica Monachini Mandy Pet Claudia Soria 《Language Resources and Evaluation》2009,43(1):57-70
Optimizing the production, maintenance and extension of lexical resources is one the crucial aspects impacting natural language
processing (NLP). A second aspect involves optimizing the process leading to their integration in applications. With this
respect, we believe that a consensual specification on monolingual, bilingual and multilingual lexicons can be a useful aid
for the various NLP actors. Within ISO, one purpose of Lexical Markup Framework (LMF, ISO-24613) is to define a standard for
lexicons that covers multilingual lexical data.
相似文献
Claudia SoriaEmail: |
36.
Monika Lachmapure Priti Paralikar Manikandan Palanisamy Monica Alves Mahendra Rai 《IET nanobiotechnology / IET》2017,11(7):809
Mycotic keratitis is mainly responsible for vision loss caused by various fungi. Sometimes, proper treatment of such infection is not possible due to unavailability of effective antifungal agents and development of resistance of such fungi to antimycotic drugs. Hence, it is necessary to search for potential antifungal agents, which can effectively eradicate fungal infection of eyes. Nanoparticles‐based antifungal drugs overcome this problem by increasing permeability and properties of drug molecules. In the present study, silver nanoparticles were synthesised by using Helminthosporium sp. and Chaetomium sp. following sequential reduction technique. The synthesised silver nanoparticles were detected primarily by UV‐visible spectrophotometer showing absorption spectra at 424 and 433 nm, respectively. Nanoparticles tracking analysis confirmed the mean particle size of silver nanoparticles as 45 and 55 nm. The synthesised AgNPs showed significant antifungal activity against fungi causing mycotic keratitis, when used alone and in combination with ketoconazole and amphotericin B in the range of 30–70 microgram per millilitre of minimum inhibitory concentration. Thus, the synthesised AgNPs can be used to enhance the activities of ketoconazole and amphotericin B.Inspec keywords: silver, nanoparticles, nanomedicine, antibacterial activity, diseases, permeability, ultraviolet spectra, visible spectra, particle sizeOther keywords: biogenic silver nanoparticles, fungi, mycotitic keratitis, vision loss, infection, antifungal agents, antimycotic drugs, antifungal drugs, permeability, Helminthosporium sp, Chaetomium sp, sequential reduction technique, UV‐visible spectrophotometer, mean particle size, ketoconazole, amphotericin B, wavelength 424 nm, wavelength 433 nm, size 45 nm, size 55 nm, Ag 相似文献
37.
38.
Marialucia Gallorini Viviana di Giacomo Valentina Di Valerio Monica Rapino Domenico Bosco Andrea Travan Mara Di Giulio Roberta Di Pietro Sergio Paoletti Amelia Cataldi Silvia Sancilio 《Journal of materials science. Materials in medicine》2016,27(12):186
Silver-based products have been proven to be effective in retarding and preventing bacterial growth since ancient times. In the field of restorative dentistry, the use of silver ions/nanoparticles has been explored to counteract bacterial infections, as silver can destroy bacterial cell walls by reacting with membrane proteins. However, it is also cytotoxic towards eukaryotic cells, which are capable of internalizing nanoparticles. In this work, we investigated the biological effects of Chitlac-nAg, a colloidal system based on a modified chitosan (Chitlac), administered for 24–48?h to a co-culture of primary human gingival fibroblasts and Streptococcus mitis in the presence of saliva, developed to mimic the microenvironment of the oral cavity. We sought to determine its efficiency to combat oral hygiene-related diseases without affecting eukaryotic cells. Cytotoxicity, reactive oxygen species production, apoptosis induction, nanoparticles uptake, and lysosome and autophagosome metabolism were evaluated. In vitro results show that Chitlac-nAg does not exert cytotoxic effects on human gingival fibroblasts, which seem to survive through a homoeostasis mechanism involving autophagy. That suggests that the novel biomaterial Chitlac-nAg could be a promising tool in the field of dentistry. 相似文献
39.
Luis TruebaJr Monica A. Torres Lucie B. Johannes Daniel Rybicki 《International Journal of Material Forming》2018,11(4):559-570
Self-reacting friction stir welding (SR-FSW), also called bobbin-tool friction stir welding (BT-FSW), is a solid state welding process similar to friction stir welding (FSW) except that the tool has two opposing shoulders instead of the shoulder and a backing plate found in FSW. The tool configuration results in greater heat input and a symmetrical weld macrostructure. A significant amount of information has been published in the literature concerning traditional FSW while little has been published about SR-FSW. An optimization experiment was performed using a factorial design to evaluate the effect of process parameters on the weld temperature, surface and internal quality, and mechanical properties of self-reacting friction stir welded aluminum alloy 6061-T6 butt joints. The parameters evaluated were tool rotational speed, traverse speed, and tool plunge force. A correlation between weld temperature, defect formation (specifically galling and void formation), and mechanical properties was found. Optimum parameters were determined for the welding of 8-mm-thick 6061-T6 plate. 相似文献
40.
Fernando Maccari Tarini Prasad Mishra Monica Keszler Tobias Braun Esmaeil Adabifiroozjaei Iliya Radulov Tianshu Jiang Enrico Bruder Olivier Guillon Leopoldo Molina-Luna Martin Bram Oliver Gutfleisch 《Advanced Engineering Materials》2023,25(18):2300252
Flash spark plasma sintering (flash SPS) is an attractive method to obtain Nd–Fe–B magnets with anisotropic magnetic properties when starting from melt-spun powders. Compared to the benchmark processing route via hot pressing with subsequent die upsetting, flash SPS promises electroplasticity as an additional deformation mechanism and reduced tool wear, while maximizing magnetic properties by tailoring the microstructure—fully dense and high texture. A detailed parameter study is conducted to understand the influence of Flash SPS parameters on the densification and magnetic properties of commercial MQU-F powder. It is revealed that the presintering conditions and preheating temperature before applying the power pulse play a major role for tailoring grain size and texture in the case of hot deformation via Flash SPS. Detailed microstructure and magnetic domain evaluation disclose the texture enhancement with increasing flash SPS temperature at the expense of coercivity. The best compromise between remanence and coercivity (1.37 T and 1195 kA m−1, respectively) is achieved through a combination of presintering at 500 °C for 120 s and preheating temperature of 600 °C, resulting in a magnet with energy product (BH)max of 350 kJm−3. These findings show the potential of flash SPS to obtain fully dense anisotropic nanocrystalline magnets with high magnetic performance. 相似文献