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91.
Emiliane Andrade Araújo Nélio José de Andrade Luis Henrique Mendes da Silva Antônio Fernandes de Carvalho Cleuber Antônio de Sá Silva Afonso Mota Ramos 《Food and Bioprocess Technology》2010,3(3):321-332
Bacteria and other microorganisms have a natural tendency to adhere to surfaces as a survival mechanism. This can occur in
many environments, including the living host, industrial systems, and natural waters. The general outcome of bacterial colonization
of a surface is biofilm formation, which consists of microorganisms immobilized in a variety of polymeric compounds generally
referred to as extracellular polymeric substances. Bacterial adhesion to a solid surface is a crucial step in the biofilm
process. This step is dependent upon van der Waals, electrostatic, and acid–base interactions. These interactions are influenced
by physicochemical properties of the substratum and the bacterial surface, such as hydrophobicity, surface charge, and electron
donor–electron acceptor properties. In addition, the roughness of the substratum and the microbiological characteristics of
the cell surface, such as cellular appendages and production of exopolysaccharides, can affect the adherence process. To date,
many strategies have been developed to decrease the adherence of bacteria to surfaces. Surface modification with the addition
of the suitable compounds makes surfaces less attractive for microorganisms and therefore prevents bacterial adherence and
biofilm formation. 相似文献
92.
Jacques P. Sauvé Antão Moura Filipe T. Marques 《Journal of Network and Systems Management》2009,17(4):422-456
A methodology for designing data center infrastructure for Information Technology (IT) services is developed. The main departure
from existing methodologies is that it evaluates and compares alternative designs using business metrics rather than purely
technical metrics. Specifically, the methodology evaluates the business impact (financial loss) imposed by imperfect infrastructure.
The methodology provides the optimal infrastructure that minimizes the sum of provisioning costs and business losses incurred
during failures and performance degradations. Several full numerical example scenarios are provided and results are analyzed.
The use of the method for dynamically provisioning an adaptive infrastructure is briefly discussed. 相似文献
93.
本文报道了北京地区56例居民骨灰样品中铷(Rb)浓度的热中子活化分析结果。结果表明,骨灰中Rb浓度呈对数正态分布,范围为1—15.4μg/g(骨灰),几何均值为5.0μg/g(骨灰),几何标准差为1.7;算术均值和标准差分别为5.5和3.3μg/g(骨灰)。在假定体内Rb浓度等于无机骨中Rb浓度条件下,估算出北京居民体内Rb平均浓度为3.0mg/kg(体内~(87)Rb平均比活度为2.8Bq/kg),体负荷量为0.21g,骨沉积量为15mg。并讨论了骨中Rb浓度与年龄和性别的关系。由体内~(87)Rb平均比活度,根据UNSCEAR1986年报告模式估算体内~(87)Rb所致居民年有效剂量当量约为1.9μSv。 相似文献
94.
Heiderose Herpich Piccoli Antônio Augusto Ulson de Souza Selene Maria Arruda Guelli Ulson de Souza 《臭氧:科学与工程》2015,37(2):170-177
Several samples of knitted cotton fabric in raw state were impregnated with a solution of industrial wetting detergent and treated directly with ozone gas in a closed chamber. Working conditions for the variables: time, pH of the impregnation solution, residual pickup and feed flow rate of oxygen (for ozone generation) were investigated to identify the effects on whiteness degree and fabric strength. The application of ozone proved to be an efficient and promising technology with low water usage. 相似文献
95.
Nadya Dencheva M. Jovita Oliveira Olga S. Carneiro António S. Pouzada Zlatan Denchev 《应用聚合物科学杂志》2010,115(5):2918-2932
The preparation of microfibrillar composites (MFCs) based on oriented blends of polyamide 6 (PA6) and high‐density polyethylene (HDPE) is described. By means of conventional processing techniques, the PA6 phase was transformed in situ into fibrils with diameters in the upper nanometer range embedded in an isotropic HDPE matrix. Three different composite materials were prepared through the variation of the HDPE/PA6 ratio with and without a compatibilizer: MFCs reinforced by long PA6 fibrils arranged as a unidirectional ply; MFCs containing middle‐length, randomly distributed reinforcing PA6 bristles; and a nonoriented PA6‐reinforced material in which the PA6 phase was globular. The evolution of the morphology in the reinforcing phase (e.g., its visible diameter, length, and aspect ratio) was followed during the various processing stages as a function of the blend composition by means of scanning electron microscopy. Synchrotron X‐ray scattering was used to characterize selected unidirectional ply composites. The presence of transcrystalline HDPE was demonstrated in the shell of the reinforcing PA6 fibrils of the final MFCs. The impact of the compatibilizer content on the average diameter and length of the fibrils was assessed. The influence of the reinforcing phase on the tensile strength and Young's modulus of the various composites was also evaluated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
96.
Groundwater Assessment at Santiago Island (Cabo Verde): A Multidisciplinary Approach to a Recurring Source of Water Supply 总被引:1,自引:0,他引:1
Paula Maria Carreira José M. Marques António Pina António Mota Gomes Paula A. Galego Fernandes Fernando Monteiro Santos 《Water Resources Management》2010,24(6):1139-1159
Groundwater resources are in many parts of the world the only source for private domestic, agricultural and public water supply.
Subsurface has also become major recipient of wastewater and solid waters especially in the developing countries. Overexploitation
of coastal aquifers and pollution are among the main problems related to groundwater resources assessment and management in
Santiago Island (Cabo Verde). Brackish groundwater is the only available water type in the region that is being provided to
numerous parts of the Island such as Praia Baixo, Montenegro, and Charco for agriculture and human supply. Solute and isotope
data obtained in different groundwater systems were used in the identification of groundwater resources degradation. In order
to understand the influence of the anthropogenic activities on the water quality and the main origin of the salts in groundwater,
a statistical approach (Principal Components Analyses—PCA) was performed on the physico-chemical data. The results obtained
indicate water–rock interaction mechanisms as the major process responsible for the groundwater quality (mainly calcium-bicarbonate
type), reflecting the lithological composition of the subsurface soil. Also, anthropogenic contamination was identified, in
several points of the island. Isotopic techniques (δ2H, δ18O and 3H content) combined with geochemistry provided comprehensive information on groundwater recharge, as well as on the identification
of salinization mechanisms (e.g. seawater intrusion, salt dissolution, and marine aerosols) of the groundwater systems, at
Santiago Island. 相似文献
97.
Organochlorine pesticide contamination in three bird species of the Embalse La Florida water reservoir in the semiarid midwest of Argentina 总被引:3,自引:0,他引:3
Organochlorine pesticides (OCs) have a variety of acute and chronic pathological effects on animals, are persistent in the environment and are accumulated in adipose tissue of animals. In Argentina there are few studies reporting the OC contamination in the fauna. Moreover, no data are available for an ecologically relevant region, the arid-semiarid midwest region of Argentina. Recently, it was reported OC contamination in the water of an important artificial water reservoir of this area, the Embalse La Florida in the San Luis province. The present study aims to provide OC baseline data for birds of Embalse La Florida and to evaluate the potential risk of OC contamination for the local avifauna. We selected two fish-eating species, Podiceps major (great grebe) and Phalacrocorax brasilianus (neotropic cormorant) and one omnivore species, Pitangus sulphuratus (great kiskadee) to evaluate OC contamination. Alpha-, beta-, delta- and gamma-hexachlorocyclohexane (SigmaHCH), p,p'-DDT, p,p'-DDD, p,p'-DDE and methoxychlor (SigmaDDT), aldrin, dieldrin, endrin and endosulfan (SigmaALD) and, cis-chlordane, trans-chlordane, heptachlor, heptachlor epoxide(SigmaCHL) were measured in adipose tissue of two male great grebes, six neotropic cormorant (3 of each sex) and four great kiskadees (2 of each sex). We detected all OC pesticides assayed [SigmaHCH range: ND to 3168.41 ng/g fat, SigmaCHL range: ND to 4961.66 ng/g fat, SigmaALD range: 287.07 to 9161.70 ng/g fat, SigmaDDT range: 1068.98 to 6479.84 ng/g fat], with the exception of p,p'-DDT. Summed OC concentration in all bird species ranged from 2684.91 to 19231.91 ng/g fat. The omnivore had significantly greater concentrations of SigmaCHLs than fish-eating species. Females of the neotropic cormorant had significantly higher amounts of SigmaHCH and SigmaCHL than males. The OC concentrations detected in birds were lower than those reported in the literature that are associated with deleterious effects on survival or reproduction in others species of birds. This study is the first report of OC contamination in birds of the midwest region of Argentina and constitutes a starting point for future studies that evaluate temporal changes of OCs in birds in this region. 相似文献
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