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81.
C57BL/10 inbred mice produce a "natural" antibody which in the presence of complement selectively lyses human blood group A erythrocytes, and the sera of females display significantly higher levels than the sera of males. This pronounced anti-A hemolysin production in females follows the appearance of specific endogenous A-determinants which are associated with water-soluble ovarian glycolipids specifically blocking the syngeneic anti-A hemolysin activity. Moreover, this hemolysin activity develops poorly in mice ovariectomized at the age of 20 days. The coincidental production of (auto)antigenic structures in morphologically and functionally normal ovarian tissue and of antibodies against them is thought to be tolerated through the modulation of a thymusdirected control mechanism.  相似文献   
82.
36 college-student snake phobics (selected on the basis of Fear Survey Schedule scores) received 1 of 4 treatments to reduce their snake avoidance behavior: self-directed friend, self-directed stranger, therapist-directed contact desensitization, or attention control. Ss in the self-directed friend condition used a manual describing contact desensitization to direct nonfearful friends to act as their therapists. Ss in the self-directed stranger condition used the same manual to direct nonfearful strangers to act as their therapists. Ss in the self-directed contact desensitization condition received standard contact desensitization, and Ss in the attention control condition received the manual and attention but no actual treatment. Behavioral and self-report assessment showed all 3 treatments relative to the control to be highly and equally effective in reducing snake avoidance behavior. It is concluded that contact desensitization can be successfully used as a "packaged" treatment in a self-control context. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
83.
Detection of N-nitrosamines in water supplies is an environmental and public health issue because many N-nitrosamines are classified as probable human carcinogens. Some analytical methods are inadequate for detecting N-nitrosodimethylamine (NDMA) at low ng/L concentrations in water due to poor extraction efficiencies and nonselective and nondistinctive GC/MS electron ionization techniques. Development of a selective, sensitive, and affordable benchtop analytical method for eight N-nitrosamines, at relevant drinking water concentrations was the primary objective of this project. A solid-phase extraction method using Ambersorb 572 and LiChrolut EN was developed in conjunction with GC/MS ammonia positive chemical ionization (PCI). Ammonia PCI shows excellent sensitivity and selectivity for N-nitrosamines, which were quantified using both isotope dilution/surrogate standard and internal standard procedures. Method detection limits for all investigated N-nitrosamines ranged from 0.4 to 1.6 ng/L. Applying our extraction method to authentic drinking water samples with dissolved organic carbon concentrations of 9 mg/L, we were able to detect N-nitrosodimethylamine (2-180 ng/L) as well as N-nitrosopyrrolidine (2-4 ng/L) and N-nitrosomorpholine (1 ng/L), two N-nitrosamines that have not been reported in drinking water to date. With high recoveries of standards and analytes, the described internal standard method offers a valuable new approach for investigating several N-nitroso compounds at ultratrace levels in drinking water.  相似文献   
84.
The synthesis of amphiphilic diblock copolypeptides consisting of poly(α-l-glutamic acid) (PLGA) and poly(γ-methyl-l-glutamate-ran-γ-stearyl-l-glutamate) with 30 mol % of stearyl substituents (PMLGSLG) and their monolayer behavior at the air-water interface have been studied. PLGA-b-PMLGSLG was synthesized via a diblock copolymer precursor consisting of poly(γ-tert-butyl-l-glutamate) (PtBuLG) and PMLGSLG blocks, with the tert-butyl group as a mild acid-labile protecting group for the carboxylic acid. The polymerization conditions were found to influence the α-helix to β-sheet content ratio and can be tuned to significantly enhance the diblock copolypeptide helicity. Purely α-helical PtBuLG-b-PMLGSLG diblock copolymers were successfully prepared. After removal of the tert-butyl group, the study of the PLGA-b-PMLGSLG amphiphilic diblock copolymers in Langmuir monolayers and Langmuir-Blodgett films demonstrated the formation of a stable α-helical double-brush structure, with the helices tilted away from the substrate surface. These double-brush monolayers combine the unique properties arising from the unidirectionally aligned helix macrodipole and the liquid-like features of the side chain mantle of the PMLGSLG block. Such systems are promising for thin film applications requiring incorporation and orientation of bio- and optical molecules.  相似文献   
85.
Planning Support Systems (PSS) for collaborative sketch planning have not become widely used in planning practice. Important reasons are inadequate functionality and usability. In this article we question if following a socio-technical method in PSS development could lead to PSS with better functionality and usability than following a traditional systems engineering method, as is sometimes suggested in literature. The former method involves close cooperation with users, whereas the latter does not. This article describes an empirical study of this question. The article describes the development, application and evaluation of two PSS for sketch planning, one developed by following the traditional systems engineering method and the other by following the socio-technical method. The PSS integrate drawing and sketching with basic geographic information system functionality and use an innovative hardware interface called Maptable. The evaluation results show that the traditionally developed PSS was immediately rejected by planning practitioners due to poor functionality and usability, whereas the PSS developed with a socio-technical approach was much more acceptable. Intense cooperation with users in agreement with the socio-technical method appeared to improve the analysis of planning tasks and user needs, leading to a PSS with a sophisticated and dedicated architecture. This PSS was considered more functional and usable than the traditionally developed PSS. In addition, the socio-technically developed PSS offers some benefits over conventional planning methods. In current state the PSS is suitable for use by professionals, and it is being further developed aiming to make it suitable for supporting collaborative planning with citizens.  相似文献   
86.
The ITER correction coils (CC) include three sets of six coils each, distributed symmetrically around the tokamak and inserted between the toroidal field (TF) and the poloidal field (PF) coils. Each pair of coils located on opposite sides with respect to the plasma is series connected with polarity such to produce asymmetric fields. These superconducting coils use a cable-in-conduit conductor, insulated, wound into multiple pancakes and inserted inside an austenitic stainless steel case. The requirements and the main features of the design are presented and the selected options reviewed in terms of their criticality in achieving the specified tolerances. The requested qualification trials are identified and reports the results obtained so far.  相似文献   
87.
Molecular markers and genetic maps are useful tools in genetic studies. Novel molecular markers and their applications have been developed in recent years. With the recent advancements in sequencing technology, the genomic sequences of an increasingly great number of fungi have become available. A novel type of molecular marker was developed to construct the first reported linkage map of the edible and economically important basidiomycete Volvariella volvacea by using 104 structural variation (SV) markers that are based on the genomic sequences. Because of the special and simple life cycle in basidiomycete, SV markers can be effectively developed by genomic comparison and tested in single spore isolates (SSIs). This stable, convenient and rapidly developed marker may assist in the construction of genetic maps and facilitate genomic research for other species of fungi.  相似文献   
88.
To study the speed choice and mental workload of elderly cyclists on electrical assisted bicycles (e-bikes) in simple and complex traffic situations compared to these on conventional bicycles, a field experiment was conducted using two instrumented bicycles. These bicycles were identical except for the electric pedal support system. Two groups were compared: elderly cyclists (65 years of age and older) and a reference group of cyclists in middle adulthood (between 30 and 45 years of age). Participants rode a fixed route with a length of approximately 3.5 km on both bicycles in counterbalanced order. The route consisted of secluded bicycle paths and roads in a residential area where cyclist have to share the road with motorized traffic. The straight sections on secluded bicycle paths were classified as simple traffic situations and the intersections in the residential area where participants had to turn left, as complex traffic situations. Speed and mental workload were measured. For the assessment of mental workload the peripheral detection task (PDT) was applied. In simple traffic situations the elderly cyclists rode an average 3.6 km/h faster on the e-bike than on the conventional bicycle. However, in complex traffic situations they rode an average only 1.7 km/h faster on the e-bike than on the conventional bicycle. Except for the fact that the cyclists in middle adulthood rode an average approximately 2.6 km/h faster on both bicycle types and in both traffic conditions, their speed patterns were very similar. The speed of the elderly cyclists on an e-bike was approximately the speed of the cyclists in middle adulthood on a conventional bicycle. For the elderly cyclist and the cyclists in middle adulthood, mental workload did not differ between bicycle type. For both groups, the mental workload was higher in complex traffic situations than in simple traffic situations. Mental workload of the elderly cyclists was somewhat higher than the mental workload of the cyclists in middle adulthood. The relatively high speed of the elderly cyclists on e-bikes in complex traffic situations and their relatively high mental workload in these situations may increase the accident risk of elderly cyclist when they ride on an e-bike.  相似文献   
89.
Ultrasound is the most commonly used clinical imaging modality. However, in applications requiring cell‐labeling, the large size and short active lifetime of ultrasound contrast agents limit their longitudinal use. Here, 100 nm radius, clinically applicable, polymeric nanoparticles containing a liquid perfluorocarbon, which enhance ultrasound contrast during repeated ultrasound imaging over the course of at least 48 h, are described. The perfluorocarbon enables monitoring the nanoparticles with quantitative 19F magnetic resonance imaging, making these particles effective multimodal imaging agents. Unlike typical core–shell perfluorocarbon‐based ultrasound contrast agents, these nanoparticles have an atypical fractal internal structure. The nonvaporizing highly hydrophobic perfluorocarbon forms multiple cores within the polymeric matrix and is, surprisingly, hydrated with water, as determined from small‐angle neutron scattering and nuclear magnetic resonance spectroscopy. Finally, the nanoparticles are used to image therapeutic dendritic cells with ultrasound in vivo, as well as with 19F MRI and fluorescence imaging, demonstrating their potential for long‐term in vivo multimodal imaging.  相似文献   
90.
To develop methods to generate, manipulate, and detect plasmonic signals by electrical means with complementary metal–oxide–semiconductor (CMOS)-compatible materials is essential to realize on-chip electronic–plasmonic transduction. Here, electrically driven, CMOS-compatible electronic–plasmonic transducers with Al–AlOX–Cu tunnel junctions as the excitation source of surface plasmon polaritons (SPPs) and Si–Cu Schottky diodes as the detector of SPPs, connected via plasmonic strip waveguides of Cu, are demonstrated. Remarkably, the electronic–plasmonic transducers exhibit overall transduction efficiency of 1.85 ± 0.03%, five times higher than previously reported transducers with two tunnel junctions (metal–insulator–metal (MIM)–MIM transducers) where SPPs are detected based on optical rectification. The result establishes a new platform to convert electronic signals to plasmonic signals via electrical means, paving the way toward CMOS-compatible plasmonic components.  相似文献   
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