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1.
海南小型露天采石场矿山数量多且呈遍地开花式分布,且不规范的开采对环境造成较大的破坏,与绿色矿山之路背道而行,相对大型矿山规范化的治理,小型矿山治理比较滞后,本文以日富采石场地质环境治理为例,通过摸清当地的地质环境条件,结合矿山现状,因地制宜地制定出日富采石场地质环境治理的具体措施,通过治理可获得林地2.6hm2,矿山安全隐患及地貌景观等矿山地质环境问题得到有效地防治,有效解决农业灌溉及周边虾塘养殖用水缺乏问题,实现较好的社会经济效益,为今后治理类似矿山提供参考。 相似文献
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《International Journal of Hydrogen Energy》2022,47(51):21613-21633
When planning large-scale 100% renewable energy systems (RES) for the year 2050, the system capacity is usually oversized for better supply-demand matching of electrical energy since solar and wind resources are highly intermittent. This causes excessive excess energy that is typically dissipated, curtailed, or sold directly. The public literature shows a lack of studies on the feasibility of using this excess for country-scale co-generation. This study presents the first investigation of utilizing this excess to generate green hydrogen gas. The concept is demonstrated for Jordan using three solar photovoltaic (PV), wind, and hybrid PV-wind RESs, all equipped with Lithium-Ion battery energy storage systems (ESSs), for hydrogen production using a polymer electrolyte membrane (PEM) system. The results show that the PV-based system has the highest demand-supply fraction (>99%). However, the wind-based system is more favorable economically, with installed RES, ESS, and PEM capacities of only 23.88 GW, 2542 GWh, and 20.66 GW. It also shows the highest hydrogen annual production rate (172.1 × 103 tons) and the lowest hydrogen cost (1.082 USD/kg). The three systems were a better option than selling excess energy directly, where they ensure annual incomes up to 2.68 billion USD while having payback periods of as low as 1.78 years. Furthermore, the hydrogen cost does not exceed 2.03 USD/kg, which is significantly lower than the expected cost of hydrogen (3 USD/kg) produced using energy from fossil fuel-based systems in 2050. 相似文献
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针对城际列车开行方案没有有效匹配城市轨道交通运能的问题,提出一种考虑区域协调性的城际列车开行方案优化方法。首先,以旅客出行费用最小和铁路运输效益最大为优化目标,考虑城际列车载客能力、出发地目的地(Original Destination,OD)客流需求和通过能力等约束;然后,在此基础上增加运能匹配度的限制,构建了考虑区域协调性的城际列车开行方案多目标非线性规划模型,并设计改进的模拟退火算法求解模型;最后,以广深城际铁路为例并进行两组对比分析。实验结果表明:考虑区域协调性的列车开行方案可以使旅客出行总广义费用降低约4.06%,铁路部门的效益提高约9.58%,旅客和铁路的系统总成本降低约23.27%;与遗传算法相比,改进的模拟退火算法在求解质量与收敛速度上均有较大提高。所提模型和算法可充分兼顾旅客和铁路双方利益,能够为城际列车开行方案优化问题提供有效解决方法。 相似文献
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复杂网络最短路径经典算法的处理效率较低,不适用于大规模复杂网络,而现有近似算法通用性有限,且计算准确率不理想,不能满足规模日益扩大的复杂网络中的最短路径计算需求。针对于此,提出基于[k]-shell的复杂网络最短路径近似算法。算法利用节点的[k]-shell值进行网络划分并引导搜索路径,利用超点聚合处理[k]-shell子网来降低路径搜索中节点和连边的规模,通过在路径搜索过程使用双向搜索树方法提高算法的计算效率和准确率。实验结果表明,算法通用性较好,在现实与仿真大规模复杂网络中均具有较高的计算效率和准确率。 相似文献
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Insider trading is a kind of criminal behavior in stock market by using nonpublic information. In recent years, it has become the major illegal activity in China’s stock market. In this study, a combination approach of GBDT (Gradient Boosting Decision Tree) and DE (Differential Evolution) is proposed to identify insider trading activities by using data of relevant indicators. First, insider trading samples occurred from year 2007 to 2017 and corresponding non-insider trading samples are collected. Next, the proposed method is trained by the GBDT, and initial parameters of the GBDT are optimized by the DE. Finally, out-of-samples are classified by the trained GBDT–DE model and its performances are evaluated. The experiment results show that our proposed method performed the best for insider trading identification under time window length of ninety days, indicating the relevant indicators under 90-days time window length are relatively more useful. Additionally, under all three time window lengths, relative importance result shows that several indicators are consistently crucial for insider trading identification. Furthermore, the proposed approach significantly outperforms other benchmark methods, demonstrating that it could be applied as an intelligent system to improve identification accuracy and efficiency for insider trading regulation in China stock market. 相似文献
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The perpetual energy production of a wind farm could be accomplished (under proper weather conditions) if no failures occurred. But even the best possible design, manufacturing, and maintenance of a system cannot eliminate the failure possibility. In order to understand and minimize the system failures, the most crucial components of the wind turbines, which are prone to failures, should be identified. Moreover, it is essential to determine and classify the criticality of the system failures according to the impact of these failure events on wind turbine safety. The present study is processing the failure data from a wind farm and uses the Fault Tree Analysis as a baseline for applying the Design Structure Matrix technique to reveal the failure and risk interactions between wind turbine subsystems. Based on the analysis performed and by introducing new importance measures, the “readiness to fail” of a subsystem in conjunction with the “failure riskiness” can determine the “failure criticality.” The value of the failure criticality can define the frame within which interventions could be done. The arising interventions could be applied either to the whole system or could be focused in specified pairs of wind turbine subsystems. In conclusion, the method analyzed in the present research can be effectively applied by the wind turbine manufacturers and the wind farm operators as an operation framework, which can lead to a limited (as possible) design‐out maintenance cost, failures' minimization, and safety maximization for the whole wind turbine system. 相似文献