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51.
Single nucleotide polymorphisms (SNPs) are the most common genetic variation in the human genome. Kinetic methods based on branch migration have proved successful for detecting SNPs because a mispair inhibits the progress of branch migration in the direction of the mispair. We have combined the effectiveness of kinetic methods with atomic force microscopy of DNA origami patterns to produce a direct visual readout of the target nucleotide contained in the probe sequence. The origami contains graphical representations of the four nucleotide alphabetic characters, A, T, G and C, and the symbol containing the test nucleotide identity vanishes in the presence of the probe. The system also works with pairs of probes, corresponding to heterozygous diploid genomes. 相似文献
52.
Nanoclays for polymer nanocomposites, paints, inks, greases and cosmetics formulations, drug delivery vehicle and waste water treatment 总被引:2,自引:0,他引:2
Hasmukh A. Patel Rajesh S. Somani Hari C. Bajaj Raksh V. Jasra 《Bulletin of Materials Science》2006,29(2):133-145
An overview of nanoclays or organically modified layered silicates (organoclays) is presented with emphasis placed on the
use of nanoclays as the reinforcement phase in polymer matrices for preparation of polymer/layered silicates nanocomposites,
rheological modifier for paints, inks and greases, drug delivery vehicle for controlled release of therapeutic agents, and
nanoclays for industrial waste water as well as potable water treatment to make further step into green environment. A little
amount of nanoclay can alter the entire properties of polymers, paints, inks and greases to a great extent by dispersing 1nm
thick layered silicate throughout the matrices. The flexibility of interlayer spacing of layered silicates accommodates therapeutic
agents which can later on be released to damaged cell. Because the release of drugs in drug-intercalated layered materials
is controllable, these new materials have a great potential as a delivery host in the pharmaceutical field. The problem of
clean water can be solved by treating industrial and municipal waste water with organoclays in combination with other sorbents
like activated carbon and alum. Organoclays have proven to be superior to any other water treatment technology in applications
where the water to be treated contains substantial amounts of oil and grease or humic acid. 相似文献
53.
Xiang Lu S. Sundar Kumar Iyer Jin Lee Brian Doyle Zhineng Fan Paul K. Chu Chenming Hu Nathan W. Cheung 《Journal of Electronic Materials》1998,27(9):1059-1066
We have demonstrated feasibility to form silicon-on-insulator (SOI) substrates using plasma immersion ion implantation (PIII)
for both separation by implantation of oxygen and ion-cut. This high throughput technique can substantially lower the high
cost of SOI substrates due to the simpler implanter design as well as ease of maintenance. For separation by plasma implantation
of oxygen wafers, secondary ion mass spectrometry analysis and cross-sectional transmission electron micrographs show continuous
buried oxide formation under a single-crystal silicon overlayer with sharp Si/SiO2 interfaces after oxygen plasma implantation and high-temperature (1300°C) annealing. Ion-cut SOI wafer fabrication technique
is implemented for the first time using PIII. The hydrogen plasma can be optimized so that only one ion species is dominant
in concentration and there are minimal effects by other residual ions on the ion-cut process. The physical mechanism of hydrogen
induced silicon surface layer cleavage has been investigated. An ideal gas law model of the microcavity internal pressure
combined with a two-dimensional finite element fracture mechanics model is used to approximate the fracture driving force
which is sufficient to overcome the silicon fracture resistance. 相似文献
54.
Data points with small variations between them are assumed to lie close to each other on a smooth varying manifold in the feature space. Such data are hard to classify into separate classes . A sequence of face pose images with closely varying pose angles can be considered as such data. The pose angles when large enough create images that are largely differing from each other, and thus, the sequence of face images can be assumed to be on or near a nonlinear manifold. In this paper, we propose an unsupervised pose estimation method for face images based on clustered locally linear manifolds using discriminant analysis. We divide the data into multiple disjointed, locally linear and separable clusters. The problem of identifying which cluster to use is solved by dividing the entire process into two steps. The first step or projection using the entire smooth manifold identifies a rough region of interest. We use clustering techniques on entire data to form the pose-dependent classes which are then used to find the first set of discriminant functions. The second step or second projection uses trained cluster(s) from this neighbourhood to obtain a second set of discriminant functions. The idea behind such an approach is that the local neighbourhood would be linear and provide better between-class separation, and hence, the classification problem would now be simpler. 相似文献
55.
Usage pattern of clothes washing (and clothes washers) are strongly related to local cultural practices. Such practices have led to the development of distinctive clothes-washing technologies in the US, Europe, and Japan. In emerging markets such as China, several types of technologies often co-exist. Some use less energy but more water (the impeller type), and some use more energy but less water (the horizontal axis type). The competition between different technologies is thought to lead to better consumer choices. However, it could also lead to changes in clothes-washing habits—from cold to hot wash, and therefore to much higher energy use. This paper examines the standard development process in China to illustrate that adoption of foreign technologies and technical standards, if not carefully calibrated to the local cultural practices, could have unintended consequences for energy use and environment. 相似文献
56.
Sree Hari Krishnan Parthasarathi R. Padmanabhan Hema A. Murthy 《International Journal of Speech Technology》2011,14(4):361-368
This paper demonstrates the robustness of group delay based features to additive noise. First, we analytically show the robustness
of group delay based representations. The analysis makes use of the fact that, for minimum-phase signals, the group delay
function can be represented in terms of the cepstral coefficients of the log-magnitude spectrum. Such a representation results
in the speech spectrum dominating over the noise spectrum, both at low and high SNRs. Further, we experimentally demonstrate
the robustness of the representation on a voice activity detection (VAD) task, comparing a group delay based VAD algorithm
with standard VAD methods as well as a magnitude-spectrum based method. 相似文献
57.
Alireza Bahadori Hari B. Vuthaluru 《International Journal of Pressure Vessels and Piping》2009,86(8):550-554
To determine whether any pressure variation in pipeline hydrostatic test is a result of temperature changes or the presence of leaks, the calculation of pressure/temperature changes is required for test sections. In these calculations, bulk modulus and volumetric expansion coefficient of fresh or sea water must be taken into account. In this study, a simple-to-use correlation is developed to predict the bulk modulus and volumetric expansion coefficient of both fresh and sea water as a function of temperature and pressure. The proposed correlation helps to cover the bulk modulus and volumetric expansion coefficient of both fresh and sea water for temperatures less than 50 °C (40 °C for sea water) as well as pressures up to 55,000 kPa (550 bar). The results can be used in follow-up calculations to determine whether any pressure variation in pipeline hydrostatic test is a result of temperature changes or the presence of leaks. The proposed correlation showed promising results with average absolute deviations for volumetric expansion coefficient and bulk modulus of water being around 0.58% and 0.08% respectively. The novel correlation is easy to use and will prove to be of immense value for project engineers to test the critical limits accurately. 相似文献
58.
59.
Ramya Iyer S.K. Tomar Suman Kapila Jiju Mani Rameshwar Singh 《Food research international (Ottawa, Ont.)》2010,43(1):103-110
This study aimed at assessing the probiotic potential of two high folate producing Streptococcus thermophilus strains (RD102 and RD104) isolated from Indian fermented milk products by both in vitro and in vivo tests. These strains were able to survive at pH 2.5 and 2% bile with a good bile salt hydrolase activity, cell surface hydrophobicity and sensitivity to most of the clinically important antibiotics. On evaluation for gastrointestinal transit tolerance these showed a viable count of 5 log cfu mL?1 and 7 log cfu mL?1, respectively in simulated gastrointestinal juice of pH 2.0 and 2% bile. During the in vivo feeding trial in mice the strains showed a viable count of about 7 log cfu g?1 faeces and 6 log cfu g?1 of large intestine, respectively. These strains were hence observed to possess favorable strain specific probiotic properties and have the potential to be a source of novel probiotics. 相似文献
60.
A simple, rapid and energy efficient approach based on copper mediated chemical reduction — solvothermal method was employed to prepare submicron size hollow carbon spheres (SHCS) using carbon tetrachloride as carbon source. The obtained SHCS were characterized by means of various physico-chemical techniques like nitrogen adsorption-desorption measurements at 77 K, XRD, SEM, TEM, EDX and FT-Raman techniques. Thus characterized samples displayed macroporous nature of carbon with carbon and chloride contents of about 73% and 12% on atomic basis respectively. The presence of chloride content may open new avenues for surface modifications of SHCS in the area of catalysis and separation science. 相似文献