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141.
Piacentini  M. 《Electronics letters》1985,21(24):1128-1129
High and medium PRF radars perform ranging by means of multiple PRFs chosen according to the Chinese remainder theorem. Unfortunately this theory does not cope with errors in range measurements. A new rule for the choice of the PRFs is proposed which is tolerant of a prescribed error amplitude in range measurements.  相似文献   
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Mice in which the gene that encodes the receptor (R) for leukemia inhibitory factor (LIF) has been deleted show abnormal growth and development of the placenta. This indicates that LIF plays an important role in placental development. The expression of LIF-R and LIF was examined in human trophoblast and decidua using in situ hybridization and immunocytochemistry. LIF-R mRNA and immunoreactivity was localized in villous and extravillous trophoblast throughout pregnancy, and in endothelial cells of the fetal villi. Strong expression of mRNA encoding LIF was detected in decidual leukocytes, which are abundant at the implantation site. Extravillous trophoblast, which invades the maternal decidua, therefore expresses LIF-R as it moves past decidual leukocytes, which express LIF mRNA. The effect of LIF on cultured human trophoblast was examined in vitro. Recombinant human LIF had no effect on [3H]thymidine incorporation by purified extravillous trophoblast, nor on expression of integrins alpha1, alpha5, or beta1 by isolated trophoblast. These results identify fetal endothelial cells and all cells of the trophoblast lineage as targets for the action of LIF in human placenta. Although its effects on trophoblast are not yet clear, LIF appears to mediate interactions between maternal decidual leukocytes and invading trophoblast. LIF may also play a critical role in controlling angiogenesis in the placental villi, since human fetal endothelial cells express LIF-R, and mice lacking a functional LIF receptor gene show altered vascular development in the placenta.  相似文献   
144.
Cooking Brassica vegetables as a domestic processing method has a great impact on health-promoting bioactive compounds: glucosinolates (GLS), flavonoids, hydroxycinnamic acids, and vitamin C. In Galicia (NorthWestern Spain), one of the most consumed horticultural crops is Brassica rapa, by using the leaves (turnip greens) and the young sprouting shoots (turnip tops) in different culinary preparations. In order to determine the effect of cooking, on turnip greens and turnip tops, bioactive GLS, flavonoids, hydroxycinnamic acids and vitamin C were analysed and simultaneously determined. The level of retention of each individual compound after cooking procedures was evaluated in the edible organs, and also in the cooking water, in order to compare their composition to a fresh uncooked control. Steaming, conventional boiling, and high-pressure cooking, traditional processing methods of this kind of vegetables, were the three domestic processing methods used in this work. Results showed that total GLS and phenolics were significantly affected by the cooking procedure and the loss rate varied among individual compounds. Steaming was the method that better preserved GLS and phenolic compounds. Conventional boiling and high-pressure cooking methods presented similar rate of losses of total GLS content (64%) and total phenolic content (more than 70%). Degradation among glucosinolate classes, aliphatic or indolic, was similar. The total flavonoids lost in turnip greens were 64% and 67% for conventional boiling and high-pressure, respectively. The main losses were caused by leaching into the cooking water. The concentration of vitamin C suffered a drastic loss in the process of sample handling and after cooking. Despite the fact that any cooking procedure affected negatively the nutritional composition of the turnip greens and tops, our results showed high retentions of individual compounds in steaming, and the lowest retentions were obtained in the traditional high-pressure cooking. High retention of health-promoting compounds in the cooking water should be considered for increasing the intake of properties of B. rapa.  相似文献   
145.
The Teleo-Reactive approach designed by N. J. Nilsson offers a high-level programming model for the development of reactive systems such as robotic vehicles. Teleo-Reactive programs are written in a way that allows engineers to define behaviour taking account of goals and changes in the state of the environment. Since Nilsson’s original definition, published in 1994, various researchers have used the Teleo-Reactive paradigm, either applied to a particular domain or extended by adding more capabilities to the original definition. This article provides a systematic literature review of 53 previous Teleo-Reactive-based studies in journals, conference proceedings and the like. The aim of this paper is to identify, appraise, select and synthesize all this high-quality research evidence relating to the use of the Teleo-Reactive paradigm. The literature has been systematically reviewed to offer an overview of the present state of this field of study and identify the principal results that have been obtained thanks to the Teleo-Reactive approach. Finally, this article details the challenges and difficulties that have to be overcome to ensure further advances in the use of this technique.  相似文献   
146.
Bioactive substances found in numerous foods can be successfully and safely used to modify various cellular functions and affect the oxidative stress. The aim of this study was to analyze the effect of a citrus-based juice (juice citrus (95%) with 5% of aronia extract (Aronia melanocarpa)) on biomarkers of oxidative stress in patients with metabolic syndrome compared with healthy individuals. The study comprised 20 healthy subjects and 33 patients with metabolic syndrome. Eighteen patients consumed daily 300 mL of a citrus-based juice during 6 months and 15 patients consumed 300 mL of a placebo beverage. The control group consumed a citrus-based juice (CJ). Before, and at sixth months after consuming of a citrus-based juice the following parameters were determined: 15-isoprostane F2, 8-hydroxydeoxyguanosine (8-OHdG), reduced and oxidized glutathione (GSH/GSSH), carbonyl groups and oxidized LDL (ox-LDL). After consuming CJ during 6 months the values of 8-OHdG, carbonyl groups and LDL-ox decreased in both analyzed groups and the values of GSH/GSSH increased. Significant differences were observed in both groups. Thus consumption of citrus-based juice improved the biomarkers of oxidative stress in metabolic syndrome patients.  相似文献   
147.
Automatically generating program translators from source and target language specifications is a non-trivial problem. In this paper we focus on the problem of automating the process of building translators between operations languages, a family of DSLs used to program satellite operations procedures. We exploit their similarities to semi-automatically build transformation tools between these DSLs. The input to our method is a collection of annotated context-free grammars. To simplify the overall translation process even more, we also propose an intermediate representation common to all operations languages. Finally, we discuss how to enrich our annotated grammars model with more advanced semantic annotations to provide a verification system for the translation process. We validate our approach by semi-automatically deriving translators between some real world operations languages, using the prototype tool which we implemented for that purpose.  相似文献   
148.
The NP-hard component set identification problem is a combinatorial problem arising in the context of knowledge discovery, information integration, and knowledge source/service composition. Considering a granular knowledge domain consisting of a large number of individual bits and pieces of domain knowledge (properties) and a large number of knowledge sources and services that provide mappings between sets of properties, the objective of the component set identification problem is to select a minimum cost combination of knowledge sources that can provide a joint mapping from a given set of initially available properties (initial knowledge) to a set of initially unknown properties (target knowledge). We provide a general framework for heuristics and consider construction heuristics that are followed by local improvement heuristics. Computational results are reported on randomly generated problem instances.  相似文献   
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150.
OBJECTIVE: To compare psychological and event-related contingencies that characterize and differentiate adolescent suicidal ideation and attempts. METHOD: Thirty-five ideators and 32 attempters (aged 12 to 17 years) consecutively referred to the suicide disorders clinic were evaluated with a semistructured interview about current and past emotional, cognitive, and behavioral states. RESULTS: Before the precipitant stressor (baseline), attempters reported significantly more hopelessness than ideators (odds ratio [OR] = 4.2, p < .05). During the suicidal episode, attempters, relative to ideators, spent more time ideating (OR = 4.3, p < .05), were more likely to isolate themselves (OR = 5.8, p < .01), and were less likely to tell anyone what they were thinking (OR = 4.5, p < .05). In contrast, ideators reported significantly more residual anger after the episode than did attempters (OR = 4.0, p < .05). All the episodes of ideation and attempts were preceded by a stress event. No differences were found between the groups on Beck Depression inventory scores. CONCLUSIONS: Preexisting hopelessness, a tendency toward isolation, not talking about ideation, and longer length of time ideating during suicidal episodes discriminated suicide attempters from suicide ideators. Knowledge of these factors may be helpful in preventive and treatment efforts with suicidal adolescents.  相似文献   
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