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51.
Large urban parks can support a diverse bird community. However, the effects of variability among habitats and of park management on bird assemblages are poorly understood. We studied bird communities within the Yarkon Park, Tel Aviv, the largest urban park in Israel. We examined species richness, abundance and community composition across 20 locations that differ in levels of park management to identify habitat variables responsible for variation in bird richness and composition. Of 91 recorded bird species, 13 were aliens (14%), 4 were urban exploiters (4%), 54 were urban adapters (60%) and 20 were migrants (22%). Management had a significant effect on native bird richness and bird community structure varied among areas with different management regimes. Species richness of all the above species’ groups was lowest in intensively managed areas. Areas with intermediate levels of management had higher or equal richness compared to unmanaged areas. The majority of urban exploiters were found at all locations within the park reaching their highest abundances in intensively managed areas. Species richness of alien birds did not vary across levels of management. Bird species richness was negatively associated with lawn cover and with distance from nearest water source and was positively associated with the number of woody plant species. We suggest that urban parks should be designed such that the heterogeneity of native vegetation is preserved, if we aim to maintain native bird species diversity and minimize urban exploiter and alien species. When lightly managed or unmanaged, urban parks can retain large remnants of sub-natural habitats and can serve as important contributors to the conservation of native biodiversity within a large urban metropolis.  相似文献   
52.
The problem of tunneling effects on pipelines is approached in the paper. Previous solutions treated the pipeline as a simple Euler–Bernoulli beam. Strictly speaking, this treatment cannot be rigorous as the pipe itself is actually a three dimensional structure loaded all around. It is therefore possible that the Euler–Bernoulli beam representation is not suitable for all cases. The current paper examines this issue by comparing analysis results of soil-pipe-tunnel interaction based on two different formulations. In one formulation the pile is represented as a Euler–Bernoulli beam, while in the other it is treated as a three dimensional structure composed of shell elements. The soil behavior and the tunneling induced displacements are identical in the two formulations, thus any variation in behavior is solely a function of the employed pipe representation method.It is found that when the relative material stiffness of the pipe and soil is small, the pipeline does not behave as a beam, and the results of the two theories differ. As the relative pipe-soil material stiffness increases the two solutions approach each other and eventually coincide for large relative pipe-soil material stiffness values. It is shown that typical concrete and steel pipes can be well represented as simple beams, while polyethylene pipes may require the shell element representation for more accurate predictions.  相似文献   
53.
时尚成衣店     
精选理由设计师以做时装设计的理念来做完全相反的建筑设计,使用可以随季节以及潮流趋势改变而变化的自由拼接组合的材料,由此让空间设计也变成为了顾客定期来消费的商品。"时装的消费者是为设计买单而不是为材料。"设计师Guy Zucker说。决定消费者购买欲的是时装是否流行和符合季节变化,而非质量。因此,对于时装设计师来说,对设计的投入和经历远远超过对质量和材料的研究。然而,在建筑领域,情况恰好相反——设计的投资远远小于材料的投资。  相似文献   
54.

The factors used in this model are financial stability, experience, references, past performance, current work load, staff availability, manpower resources, company organization, office location, experience in geographic location of project, quality performance, failure to complete contracts, procurement experience, safety consciousness and claim attitude.  相似文献   
55.
Design organizations play a major role in the construction industry: they are the media that transfer the requirements of the client to the contractor and ensure that they are met. Thus they need to provide a high quality of service to ensure that their client's project achieves the best possible standards of cost, time and quality. Seventy quality practices (QP) were identified as having a bearing on the quality of service provided by the local design organizations. These quality practices were grouped into fifteen sections termed quality sections (QS). The prevalence of these practices among the local design organizations was surveyed and determined. The results indicate a significant need for improvement in the quality sections ‘working relationship’, ‘employee training and education’, and ‘performance quality audit’. The study reveals the need for the establishment of a design code, and evaluation standards for local design organizations.  相似文献   
56.
Here, we have systematically investigated how the nature of the support influenced the oxygen mobility and activities in catalysts comprised of AgPt nanoshells deposited over inorganic oxides. We first synthesized AgPt nanoshells by galvanic replacement reaction between Ag nanospheres and PtCl6 2? (aq) combined with Pt reduction using hydroquinone as an auxiliary reducing agent. The nanoshells were then supported over TiO2, Al2O3 and CeO2. Through this methodology, we prepared materials with similar metallic nanoparticle AgPt compositions (~0.99 wt% Pt), sizes (43 ± 2 nm diameter), spherical shapes, surface morphologies, number of active sites \( (\sim4.5\;\upmu{\text{mol}}\;{\text{g}}_{{{\text{cat}} .}}^{ - 1} ) \) and uniform distribution over the supports, differing only in terms of the nature of the support. The oxide reduction temperature, its capability of re-oxidation and the presence of oxygen mobility were strongly dependent on the metal–support interaction between AgPt nanoshells and oxide supports. These properties have significantly influenced their catalytic performances toward the CO oxidation. At 230 °C, the CO oxidation TOF was 40.4 ± 0.4, 6.9 ± 1, 1.4 ± 0.8 min?1 for AgPt/CeO2, AgPt/TiO2, AgPt/Al2O3, respectively. These differences were attributed to the concentration of oxygen vacancies in each catalyst, which presented exactly the same trend as that of the catalytic activities. Our results may have important contributions to the design of highly active metal oxide-based catalysts toward gas-phase oxidation transformations.  相似文献   
57.
Replacement of the damaged scar tissue created by a myocardial infarction is the goal of cardiac tissue engineering. However, once the implanted tissue is in place, monitoring its function is difficult and involves indirect methods, while intervention necessarily requires an invasive procedure and available medical attention. To overcome this, methods of integrating electronic components into engineered tissues have been recently presented. These allow for remote monitoring of tissue function as well as intervention through stimulation and controlled drug release. Here, an improved hybrid microelectronic tissue construct capable of withstanding the dynamic environment of the beating heart without compromising electronic or mechanical functionality is reported. While the reported system is enabled to sense the function of the engineered tissue and provide stimulation for pacing, an electroactive polymer on the electronics enables it to release multiple drugs in parallel. It is envisioned that the integration of microelectronic devices into engineered tissues will provide a better way to monitor patient health from afar, as well as provide facile, more exact methods to control the healing process.  相似文献   
58.
The design of efficient time compression support hardware for built-in self-testing (BIST) is of great importance in the design and manufacture of VLSI circuits. The test data outputs in BIST are ultimately compressed by time compaction hardware, commonly called a response analyzer, into signatures. Several output response compaction techniques to aid in the synthesis of such support circuits already exist in literature, and parity bit signature coupled with exhaustive testing is already well known to have certain very desirable properties in this context. This paper reports new time compaction techniques utilizing the concept of parity bit signature that facilitates implementing such support circuits using nonexhaustive or compact test sets, with the primary objective of minimizing the storage requirements for the circuit under test (CUT) while maintaining the fault coverage information as best as possible.  相似文献   
59.
A series of Zn1-xCo(x)O epitaxial films around 100 nm with nominal Co concentration from 5% to 15% was prepared by ultra high vacuum (UHV) magnetron reactive sputtering. The optical, magnetic and magneto-transport properties of this series of Zn1-xCo(x)O epitaxial films were investigated, respectively. Resonant Raman spectra indicate the high structural and crystalline quality of these Zn1-xCo(x)O (5 < or = x < or = 15%) films, and confirm a consistent correlation between the substituting Co ions content with the Co doping concentration as well. Paramagnetism, superparamagnetism and ferromagnetism with altered Curie temperature from low temperatures to above room temperatures have been observed in these films by SQUID magnetometry. The broad blocking temperature range indicates the presence of inhomogenous distribution of the magnetic nano-clusters in the superparamagnetic films. However, the magneto-transport behaviors do not strongly respond to the change of the magnetic properties from paramagnetism to ferromagnetism of these Zn1-xCo(x)O films. The lack of efficient coupling between the inhomogenous magnetic nanoclusters and the carrier system in ferromagnetic Zn1-xCo(x)O films highlights the absence of the intrinsic magnetic origins in high structural quality Zn1-xCo(x)O (5 < or = x < or = 15%) epitaxial films. On the other hand, the competition between the spin alignments and the inhomogenous local disorder effect by magnetic ions is suggested to be responsible for the carrier properties and the oberseved magnetoresistance in these Co doping Zn1-xCo(x)O (5 < or = x < or = 15%) epitaxial films.  相似文献   
60.
Cystoliths are amorphous calcium carbonate bodies that form in the leaves of some plant families. Cystoliths are regularly distributed in the epidermis and protrude into the photosynthetic tissue, the mesophyll. The photosynthetic pigments generate a steep light gradient in the leaf. Under most illumination regimes the outer mesophyll is light saturated, thus the photosynthetic apparatus is kinetically unable to use the excess light for photochemistry. Here we use micro‐scale modulated fluorometry to demonstrate that light scattered by the cystoliths is distributed from the photosynthetically inefficient upper tissue to the efficient, but light deprived, lower tissue. The results prove that the presence of light scatterers reduces the steep light gradient, thus enabling the leaf to use the incoming light flux more efficiently. MicroCT and electron microscopy confirm that the spatial distribution of the minerals is compatible with their optical function. During the study we encountered large calcium oxalate druses in the same anatomical location as the cystoliths. These druses proved to have similar light scattering functions as the cystoliths. This study shows that certain minerals in the leaves of different plants distribute the light flux more evenly inside the leaf.  相似文献   
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