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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
AN Reshetilov DA Efremov PV Iliasov AM Boronin NI Kukushskin RV Greene TD Leathers 《Canadian Metallurgical Quarterly》1998,13(7-8):795-799
Amperometric biosensors register oxygen depletion in response to analyte catabolism, and thus are limited by the availability of dissolved oxygen. Microbial sensors containing immobilized cells of Gluconobacter oxydans were hyperoxygenated to 400% of control levels and the effects on sensor responses to glucose were determined. Oxygenated perfluorodecalin (a completely fluorinated organic substance) was as effective in hyperoxygenation as direct sparging with O2, increasing sensor base medium oxygen concentrations from 9.3 to 37 mg/l. Hyperoxygenation enhanced maximal biosensor response amplitudes, particularly at high cell loading densities. Maximal response rates were also improved, although less dramatically. Results suggest that hyperoxygenation may be a new general approach for modulating biosensor responses. 相似文献
32.
Of 1,666 patients who underwent fine needle aspiration for breast lumps, 4 developed pneumothorax as a complication. The incidence of this complication in our patients is 1:417. The clinical manifestations were immediate chest pain, shoulder pain and, occasionally, dyspnea that developed later. Observation is sufficient treatment in most patients, and rarely is drainage of the pneumothorax required. 相似文献
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气化炉自动建模系统研究 总被引:1,自引:0,他引:1
为了减轻建模人员在建模公式推导、逻辑关系推导和编制仿真程序的工作量,设计了气化炉自动建模系统。该系统在反应物为多种气体、多种固体(均考虑为单筛分)的条件下,按照小室模型的框架自动列写相应各个物质的质量、能量平衡方程,并自动生成相应的计算机程序,方便仿真计算。由于该系统避开了工程中常用的纯数值建模的思路,采用了新的数学工具-以符号运算特长的计算机代数系统为计算平台,才使得该系统具有强大的逻辑关系推导能力。该系统在某气化炉的建模过程中得到了验证和示范,事实表明:该系统大大减少了气化炉的建模工作量,特别是减少由于化学反应假定的不同带来的建模复杂性,对于建模与仿真研究新方法的突破有所贡献。 相似文献
36.
脉冲激光沉积SrBi2Ta2O9铁电薄膜电容特性研究 总被引:2,自引:0,他引:2
用PLD方法成功地制备了SBT铁电薄膜,并制作成Pt/SBT/Pt薄膜电容器。SBT薄膜的晶面取向以(008)和(115)为主。在5V电压下,极化反转,并且得到较饱和的电滞回线,剩余极化强度和矫顽电场分别为84μC/cm2和57kv/cm。IV特性测试显示两个对称的双稳峰,并得到零电压下,面积为314×104μm2,厚度为035μm的电容器,电容约为560pF,介电常数约为600。疲劳测试表明Pt/SBT/Pt具有优良的抗疲劳特性。 相似文献
37.
ID Zakharov AM Magasumov NI Simonova IaL E?del''man IuV Simenido 《Canadian Metallurgical Quarterly》1997,90(12):8-12
The authors present results of social and ecologic study carried out in Ufa. The results describe the course of ecologically important processes and phenomena in correlation with the public subjective understanding. Public health is influenced by hygienic parameters of food and water quality as well as a complex of social, economic and psychologic factors. Weak correlation between those parameters and ambient air pollution necessitates more accurate approach to ecologic mapping of cities and to manipulation with data on lower atmosphere pollution with chemical hazards. 相似文献
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为了研究互联电力系统在级联事件下的频率和电压长期动态特性及其控制,提出了一种网络结构保留的多区域互联系统长期动态仿真模型和算法。与动态潮流计算相似,模型假定系统已渡过初始的暂态稳定阶段且有足够阻尼,从而忽略同一控制区域的机组间相对摇摆,即假定每个控制区域具有统一的频率动态,即区域内惯量中心动态,以便仿真几分钟及更长时间的长期动态。IEEE 30节点3区域系统的仿真结果表明了文中建议的仿真模型的可行性和计算方法的有效性;与详细机电暂态仿真软件仿真结果的比较表明,“区域统一频率动态”假定引起的系统长期动态仿真误差在工程上可以接受。从而为进一步开展级联事件下的频率和电压长期动态的稳定控制和协调提供了仿真工具。 相似文献
40.
Mathai P. Shapiro B. 《Components and Packaging Technologies, IEEE Transactions on》2007,30(2):317-329
Heat conduction in an electronic device is commonly modeled as a discretized thermal system (e.g., finite element or finite difference models) that typically uses large matrices for solving complex problems. The large size of electronic-system heat transfer models can be reduced using model reduction methods and the resulting reduced-order models can yield accurate results with far less computational costs. Electronic devices are typically composed of components, like chips, printed circuit boards, and heat sinks that are coupled together. There are two ways of creating reduced-order models for devices that have many coupled components. The first way is to create a single reduced-order model of the entire device. The second way is to interconnect reduced-order models of the components that constitute the device. The second choice (which we call the "reduce then interconnect" approach) allows the heat transfer specialist to perform quick simulations of different architectures of the device by using a library of reduced-order models of the different components that make up the device. However, interconnecting reduced-order models in a straightforward manner can result in unstable behavior. The purpose of this paper is two-fold: creating reduced-order models of the components using a Krylov subspace algorithm and interconnecting the reduced-order models in a stable manner using concepts from control theory. In this paper, we explain the logic behind the "reduce then interconnect" approach, formulate a control-theoretic method for it, and finally exhibit the whole process numerically, by applying it to an example heat conduction problem 相似文献