全文获取类型
收费全文 | 1125篇 |
免费 | 36篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 11篇 |
综合类 | 6篇 |
化学工业 | 115篇 |
金属工艺 | 16篇 |
机械仪表 | 11篇 |
建筑科学 | 36篇 |
能源动力 | 19篇 |
轻工业 | 51篇 |
石油天然气 | 1篇 |
无线电 | 160篇 |
一般工业技术 | 184篇 |
冶金工业 | 400篇 |
原子能技术 | 2篇 |
自动化技术 | 153篇 |
出版年
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 6篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 19篇 |
2013年 | 44篇 |
2012年 | 24篇 |
2011年 | 30篇 |
2010年 | 17篇 |
2009年 | 46篇 |
2008年 | 44篇 |
2007年 | 47篇 |
2006年 | 38篇 |
2005年 | 37篇 |
2004年 | 37篇 |
2003年 | 37篇 |
2002年 | 35篇 |
2001年 | 30篇 |
2000年 | 31篇 |
1999年 | 42篇 |
1998年 | 138篇 |
1997年 | 90篇 |
1996年 | 60篇 |
1995年 | 29篇 |
1994年 | 31篇 |
1993年 | 35篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有1165条查询结果,搜索用时 31 毫秒
111.
AM el-Shirbiny H Yeung M Imbriaco J Michaeli H Macapinlac SM Larson 《Canadian Metallurgical Quarterly》1997,38(8):1208-1210
Experience of scintigraphic detection of bone lesion and active bone marrow involvement of multiple myeloma, especially with sestamibi and FDG-PET scans is in evolution. We report a case of intense sestamibi uptake in bone marrow correlating with the extent of the disease, while FDG-PET scans showed activity only in areas of active disease progression associated with pain. Technetium-99m-sestamibi appears to indicate the extent of the disease, while [18F]FDG-PET scans show sites of active tumor proliferation and may be useful in directing local therapy such as radiation. 相似文献
112.
113.
The sorption/desorption characteristics of heavy metals onto/from soil particle surfaces are the primary factors controlling the success of the remediation of heavy-metal contaminated soils. These characteristics are pH-dependent, chemical-specific, and reversible; and can be modified by enhancement agents such as chelates and surfactants. In this study, batch experiments were conducted to evaluate the feasibility of using citric acid industrial wastewater (CAIW) to desorb cadmium from a natural clay from Shanghai, China at different soil mixture pHs. It can be observed from the results that the proportion of cadmium desorbed from the soil using synthesized CAIW is generally satisfactory, i.e., >60%, when the soil mixture pH is lower than 6. However, the proportion of desorbed cadmium decreases significantly with increase in soil mixture pH. The dominant cadmium desorption mechanism using CAIW is the complexion of cadmium with citric acid and acetic acid in CAIW. It is concluded that CAIW can be a promising enhancement agent for the remediation of cadmium-contaminated natural soils when the environmental conditions are favorable. As a result, CAIW, a waste product itself, can be put into productive use in soil remediation. 相似文献
114.
以创新理论为基础,通过对家具产品设计中创新因素的本质分析,论述了家具产品设计创新的内涵与特性;通过对越南家具设计的现状分析,指出越南家具产业在设计创新方面的缺乏。在此基础上,提出了基于家具设计创新的越南家具产业竞争力提升的途径,分别加强以人为本、以持续发展为指导思想、以环保作为任务、以文化为艺术灵魂和以高科技为手段。 相似文献
115.
Herein, we demonstrated a new optical microscopy method to selectively image small-size gold nanoparticles (GNPs) inside noisy living cells through determination of the difference image between the probe beam (illuminated at the resonance wavelength of GNPs, 532 nm) and the reference beam (illuminated at 473 nm). From computer simulation and single-particle imaging experiments, we demonstrated that GNPs with a diameter of 45 nm could be selectively imaged in the GNPs/cell lysates mixture and inside living cells by dual-wavelength difference (DWD) imaging. The diffusion dynamics of nucleic acids functionalized GNPs on cell membranes and the internalization kinetics of these GNPs by living cells were explored with this method. Our real-time tracking experiments showed that statistically 80% of GNPs were under restricted diffusion on the cell membrane. The cell cytoskeleton fence effect, as observed in the single-particle tracking experiments, may be one of the main factors for the restricted diffusion mode. 相似文献
116.
Facile Generation of L10‐FePt Nanodot Arrays from a Nanopatterned Metallopolymer Blend of Iron and Platinum Homopolymers
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Qingchen Dong Guijun Li Cheuk‐Lam Ho Chi‐Wah Leung Philip Wing‐Tat Pong Ian Manners Wai‐Yeung Wong 《Advanced functional materials》2014,24(6):857-862
Hard ferromagnetic (L10 phase) FePt alloy nanoparticles (NPs) with extremely high magnetocrystalline anisotropy are considered to be one of the most promising candidates for the next generation of ultrahigh‐density data storage system. The question of how to generate ordered patterns of L10‐FePt NPs and how to transform the technology for practical applications represents a key current challenge. Here the direct synthesis of L10 phase FePt NPs by pyrolysis of Fe‐containing and Pt‐containing metallopolymer blend without post‐annealing treatment is reported. Rapid single‐step fabrication of large‐area nanodot arrays (periodicity of 500 nm) of L10‐ordered FePt NPs can also be achieved by employing the metallopolymer blend, which possesses excellent solubility in most organic solvents and good solution processability, as the precursor through nanoimprint lithography (NIL). Magnetic force microscopy (MFM) imaging of the nanodot pattern indicates that the patterned L10 phase FePt NPs are capable of exhibiting decent magnetic response, which suggests a great potential to be utilized directly in the fabrication of bit patterned media (BPM) for the next generation of magnetic recording technology. 相似文献
117.
Baranyi P. Varkonyi-Koczy A.R. Yeung Yam Patton R.J. 《IEEE transactions on instrumentation and measurement》2005,54(1):52-60
One direction of measured data-set based modeling applies fuzzy logic identification tools and results in a fuzzy rule-base model. A typical problem of fuzzy identification methods is that the complexity of the resulting fuzzy rule-base, namely the number of rules in the rule-base, explodes with the modeling accuracy. As a result, the topic of fuzzy rule-base complexity reduction techniques emerged in the last decade. A common disadvantage of fuzzy rule-base complexity reduction methods is that the resulting complexity minimized fuzzy-rule bases cannot be simply adapted to new information. If we have new information that cannot be described by the fuzzy rules of the complexity minimized fuzzy rule-base, then we have two choices. The first choice is to add new fuzzy rules to the fuzzy rule-base until the new information can be described. The second choice is to modify the new information until it can be described by the fuzzy rule-base without using additional fuzzy rules. This second case has the prominent role if the number of fuzzy rules in the fuzzy rule-base is limited. This paper proposes a method for the second choice. The proposed method minimizes the necessary modification of the new information. This paper focuses attention on a recent complexity reduction method, termed Higher Order Singular Value Decomposition (HOSVD)-based complexity reduction, and Takagi-Sugeno (TS) inference operator-based fuzzy rule-bases. An example is used to provide the validation of the proposed method. In order to demonstrate the effectiveness of the proposed method, a control system of a differential-steered automatic guided vehicle is modeled in the paper. 相似文献
118.
The concept of providing energy conservation programs with monitoring and control via two-way communication (TWCC) systems will be one of the solutions that utilities will employ in the conservation of the nation's valuable natural resources. The development of microelectronic technology is changing the manner in which meters will be read. There are many methods currently available in the market that enable retrieval of data remotely from a customer's premise. The potential of this technology and its applications can be endless. In the area of automatic meter reading (AMR), current technology is in a state of evolution where no single method excels. Development of the new “information superhighway” industry is likely to promote standards based upon open systems and open protocols. Current AMR technologies are described 相似文献
119.
The putative E1 of hepatitis C virus (HCV) was expressed in Escherichia coli using a glutathione-S-transferase (GST) fusion protein system. The full length E1 protein is difficult to express. A series of E1 DNA fragments was generated and used for expression vector construction. Fusion proteins containing the E1 C-terminal region could not be expressed. When this region was truncated, the fusion proteins were synthesized to high levels. The possibility of this C-terminal region hampering the production of fusion protein was further explored. A construct with this segment directly fused to the C-terminus of GST indeed generated no detectable recombinant protein. According to the predicted structure of E1, this region may have membrane-associating properties. The expression results suggest a general approach to facilitate the production of viral membrane proteins in prokaryotes. Furthermore, these recombinant E1 proteins generated as antigens were used for Western blotting with sera from HCV-infected individuals. It was found that E1 is antigenic during HCV natural infection. 相似文献
120.
HS Lee KA Gwee LY Teng JY Kang KG Yeoh A Wee BC Chua 《Canadian Metallurgical Quarterly》1998,10(7):569-572
OBJECTIVE: Isotope ratio mass spectrometry (IRMS) is the accepted method for accurately measuring the 13CO2:12CO2 ratio in the non-invasive and non-radioactive [13C]urea breath test (13C-UBT) for Helicobactor pylori. The IRMS instrument, an expensive and highly specialized analyser, is rarely available. The objective of this project was to modify and validate the use of a simple bench-top gas chromatograph-mass selective detector (GC-MSD) for 13C-UBT. METHODS: Breath samples from 71 patients were taken at baseline and 30 min after ingestion of 100 mg [13C]urea. The breath samples were analysed using GC-MSD in the selected ion monitoring mode. The reference 13CO2:12CO2 ratio was from NBS19 obtained from the US National Institute of Standards and Technology. 13CO2:12CO2 ratios of the breath samples were determined. Excess delta per thousand (per mil, delta/thousand) of the 30 min sample over the baseline (deltadelta/thousand) of > or = 6deltadelta/thousand was considered H. pylori positive. Results from 13C-UBT and histology determined blind to each other were compared. RESULTS: The coefficient of variation of the reference 13CO2:12CO2 ratio was 0.06%. Using histology as the 'gold standard', the sensitivity (97.9%) and specificity (95.8%) of the GC-MSD 13C-UBT were comparable to those of other methods of H. pylori diagnosis. CONCLUSION: A gas chromatograph coupled to a mass selective detector that is available in many analytical and biomedical laboratories can be used for the 13C-UBT. This method will increase the availability and reduce the cost of this non-invasive, non-radioactive diagnostic test. 相似文献