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71.
The development of a direct competitive ELISA for the detection of a broad range of sulfonylurea herbicides (SUs) is described. Polyclonal antibodies were generated in rabbits using three different immunizing haptens. Antiserum with the broadest specificity was obtained with a mesosulfuronbenzylamine derivative which was coupled via a succinic acid spacer to keyhole limpet hemocyanine. A heterologous enzyme tracer which did not contain the succinic acid bridge was prepared using activated horseradish peroxidase. The direct competitive ELISA was optimized and applied for spiked tap and surface water samples. From 30 SUs, 8 compounds showed a molar cross-reactivity (CR) higher than 100% (this value was set for the hapten) and 11 compounds CRs between 10% and 100%. The ELISA can detect 16 SUs at a concentration of 0.1 microg/L or lower. Different surface and tap water samples were spiked with chlorimuron ethyl, metsulfuron methyl, or primisulfuron methyl at concentrations of 100, 200, or 500 ng/L and subsequently analyzed by both ELISA and HPLC-UV. Correlation analysis revealed good agreement between both methods (r2 = 0.983/0.948/0.982; n = 21 for each analyte). Using ELISA, no sample pretreatment other than filtration was necessary. 相似文献
72.
Radivojevic I Haisch C Niessner R Florek S Becker-Ross H Panne U 《Analytical chemistry》2004,76(6):1648-1656
A new setup for microanalysis by laser-induced plasma spectroscopy in the VUV range is presented and described in detail. The system features an integrated ablation and detection module with a newly designed VUV echelle system. The echelle permits a full spectral coverage between 150 and 300 nm with a resolving power lambda/Deltalambda between 11,000 and 15,000. At present, the ablation module permits a microanalysis with a crater size of 25 microm and a nominal depth resolution with an ablation rate of 150 nm/pulse. The VUV performance was demonstrated for bulk analysis of steel; detection limits for sulfur, carbon, and phosphorus were in the lower milligram per kilogram range. The VUV scanning and mapping performance for heterogeneous matrixes was illustrated for mineral bottom ash samples from a waste incineration process. 相似文献
73.
In a simple diode system for asymmetric radio frequency sputtering, steel specimens were covered with iron oxide and the corrosion behaviour was studied by electrochemical methods. The specimens, which were covered with a compact layer of Fe2O3, had film resistances of 108–1015 Ω cm, due to the conditions of production and the purity of the target material. Potentiometric measurements on steel electrodes covered with quasi-crystalline α-Fe2O3 showed a distinct passivation of the basic material in neutral and slightly acid media. An outlook is given concerning future fundamental studies on this problem. 相似文献
74.
Particle size analysis of particles < 10 μm – methods and difficulties . A review of possible methods for the determination of particle size distributions in the range < 10 μm is presented. Important factors regarding the specimen dispersion are dealt with, particularly those which must be taken into consideration in the “fines” region, and the limits and difficulties of individual analytical equipment are illustrated with the aid of examples. Finally, analytical results obtained by various methods of measurement are compared and the criteria of assessment such as operational possibility and costing are discussed. 相似文献
75.
In recent years, a rising number of different table waters supersaturated with oxygen have hit the market with claims of both positive health effects and an increase in athletic performance. In addition to research on the correctness of these claims and their possible physiological reasons, the appearance of oxygen supersaturation as a marketing promise also creates a need for appropriate analytical techniques allowing a rapid and reliable determination of oxygen contents in such waters. Here, we present NMR relaxometry as a possible analytical tool for such studies. NMR relaxation in oxygen supersaturated water is not only of interest in the context of monitoring the oxygen content in such drinking water products, but also might offer some interesting possibilities in medical and environmental science MRI applications. As a contact-less measuring method, NMR relaxometry avoids disturbance of the measurement due to outgassing. The method was applied in the concentration range from 10 mg l(-1) to over 100 mg l(-1) dissolved oxygen. In addition to freshly sampled drinking waters, also oxygen losses during storage of the water in open drinking vials was studied. 相似文献
76.
Fall BI Eberlein-König B Behrendt H Niessner R Ring J Weller MG 《Analytical chemistry》2003,75(3):556-562
The described in vitro test system for allergy diagnosis is based on microscope glass slides activated with (3-glycidyloxypropyl)trimethoxysilane. Allergen solutions are immobilized as small droplets (approximately 10 nL) on the activated glass slides with a piezoelectric arrayer. In contrast to other tests for specific IgE, such as Pharmacia CAP FEIA, AlaSTAT, or FAST, only a 25-microL serum sample is needed for the screening of allergen-specific IgE against a multitude of allergens and the test can be performed in less than 1 h. Compared with multiallergen dipstick screening tests (e.g., IgEquick, CMG Immunodot) based on multiallergen-coated nitrocellulose strips, the measurement of the microarray-based system can be performed automatically. The chemiluminescence intensities are detected with a sensitive CCD camera. Allergen extracts and recombinant/purified allergens (24 preparations) have been used on the same modified surface for the screening of allergen-specific IgE. With these disposable microarray slides, it is possible to distinguish between patients with and without elevated levels of allergen-specific IgE. Repeated measurements of serum samples demonstrated a sufficient reproducibility. Detection limits (microg/L) of 0.35 (r Betvl), 0.16 (PLA2), and 1.9 (Der p1) were achieved. 相似文献
77.
IT infrastructure, such as servers and networking equipment, accounts for a large proportion of the IT costs in modern organizations.
Typically, this IT infrastructure is shared among multiple applications and customers. Cost allocation of shared IT infrastructure
is difficult and regularly based on biased cost allocation keys, which often causes free-rider problems. Measuring usage is
technically difficult and incurs high costs. In this paper we propose a method to derive adequate estimators for the resource
consumption of a customer-oriented service. These so-called resource profiles can then provide a basis for cost allocation
keys. The estimators are derived from a series of load tests, as they are typically done before an application is launched
in larger organizations. Such profiles need to be unbiased and precise even in cases of varying workloads and in rather heterogeneous
environments. We describe the results of a set of experiments in an infrastructure provided by the BMW Group, and illustrate
how the estimation can be integrated into existing IT service management processes. In our experiments we use Queuing Networks
to validate the estimated resource profiles under different workloads. 相似文献
78.
Reinhard König Cezary Sielużycki Piotr J. Durka 《Journal of Low Temperature Physics》2007,146(5-6):697-718
Low-temperature superconductivity plays an important role in some specific biomedical applications, and, in particular, in
non-invasive imaging methods of human brain activity. Superconducting magnets are indispensable for functional magnetic resonance
imaging (fMRI) which allows functional imaging of the brain with high spatial but poor temporal resolution. Superconducting
quantum interference devices (SQUIDs) are the most sensitive magnetic field detectors. Up to a few hundreds of SQUIDs are
nowdays used in modern whole-head magnetoencephalography (MEG) systems. They allow tracking brain activation with a superior
temporal resolution of milliseconds, which is a quintessential condition for the monitoring of brain dynamics and the understanding
of information processing in the human brain. We introduce the prerequisites of MEG data acquisition and briefly review two
established methods of biomagnetic signal processing: The concept of signal averaging, and the subsequent source identification
as a solution of the biomagnetic inverse problem. Beside these standard techniques, we discuss advanced methods for signal
processing in MEG, which take into account the frequency content of the recorded signal. We briefly refer to the prospects
of Fourier analysis and wavelet transform in MEG data analysis, and suggest matching pursuit as a promising tool for signal
decomposition and reconstruction with high resolution in time-frequency plane. 相似文献
79.
Bidirectional Texture Functions (BTFs) are among the highest quality material representations available today and thus well suited whenever an exact reproduction of the appearance of a material or complete object is required. In recent years, BTFs have started to find application in various industrial settings and there is also a growing interest in the cultural heritage domain. BTFs are usually measured from real‐world samples and easily consist of tens or hundreds of gigabytes. By using data‐driven compression schemes, such as matrix or tensor factorization, a more compact but still faithful representation can be derived. This way, BTFs can be employed for real‐time rendering of photo‐realistic materials on the GPU. However, scenes containing multiple BTFs or even single objects with high‐resolution BTFs easily exceed available GPU memory on today's consumer graphics cards unless quality is drastically reduced by the compression. In this paper, we propose the Bidirectional Sparse Virtual Texture Function, a hierarchical level‐of‐detail approach for the real‐time rendering of large BTFs that requires only a small amount of GPU memory. More importantly, for larger numbers or higher resolutions, the GPU and CPU memory demand grows only marginally and the GPU workload remains constant. For this, we extend the concept of sparse virtual textures by choosing an appropriate prioritization, finding a trade off between factorization components and spatial resolution. Besides GPU memory, the high demand on bandwidth poses a serious limitation for the deployment of conventional BTFs. We show that our proposed representation can be combined with an additional transmission compression and then be employed for streaming the BTF data to the GPU from from local storage media or over the Internet. In combination with the introduced prioritization this allows for the fast visualization of relevant content in the users field of view and a consecutive progressive refinement. 相似文献
80.
In applicative theories the recursion theorem provides a term
which solves recursive equations. However, it is not provable that a solution obtained by
is minimal. In the present paper we introduce an applicative theory in which it is possible to define a least fixed point operator. Still, our theory has a standard recursion theoretic interpretation. 相似文献