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511.
用不同粒度交联聚苯乙烯(含DVB7%)在CS_2中与AlCl_3或TiCl_4作用制得一种稳定的复合物.研究了不同粒度复合物存在下二茂铁甲醛与乙二醇的缩醛化反应,对反应条件进行了较为详细的研究,结果表明这两种载体催化剂对二茂铁甲醛与乙二醇的缩合反应均有良好的催化效果,而且使用方便,反应产物易于分离.  相似文献   
512.
SXSES-DSS数据库系统通过投影技术将多维层次的数据结构转化为二维表结构,实现了数据的关系存储。系统建立了无数据管理字典,采用压缩索引,以管理数据的描述信息,节约存储空间,提高查询速度。为了能够自动产生导出数据和进行图表输出,系统提供了自定义算术表达式和图表输出功能。此外并利用ORACLE提供的机制,实现了系统的完整性、一致性和安全性控制。  相似文献   
513.
针对现有手背静脉识别利用手背静脉特征较少, 识别率较低的问题, 提出了一种基于特征点距离的手背静脉特征融合方法。该方法首先对手背静脉进行细化, 对不变矩特征的量化值求和再进行匹配; 然后提取手背静脉的端点及交叉点, 利用改进的Hausdorff 距离进行匹配, 从而去除零距离点的影响, 提高两幅图之间的非相似性; 最后将这两种匹配方法进行加权融合。实验证明, 该融合算法识别率可达96. 75%, 且运行时间仅为0. 97 s。  相似文献   
514.
A main aspect of underwater passive navigation is how to identify the vehicle location on an existing gravity map, and several matching algorithms as ICCP and SITAN are the most prevalent methods that many scholars are using. In this paper, a novel algorithm that is different from matching algorithms for passive navigation is developed. The algorithm implements underwater passive navigation by directly estimating the inertial errors through Kalman filter algorithm, and the key part of this implementation is a Fourier series based local geopotential model. Firstly, the principle of local geopotential model based on Fourier series is introduced in this paper, thus the discrete gravity anomalies data can be expressed analytically with respect to geographic coordinates to establish the observation equation required in the application of Kalman filter. Whereafter, the indicated gravity anomalies can be gotten by substituting the inertial positions to existing gravity anomalies map. Finally, the classical extended Kalman filter is introduced with the differences between measured gravity and indicated gravity used as observations to optimally estimate the errors of Inertial Navigation System (INS). This navigation algorithm is tested on simulated data with encouraging results. Although this algorithm is developed for underwater navigation using gravity data, it is equally applicable to other domains, for example vehicle navigation on magnetic or terrain data.  相似文献   
515.
In this paper, we investigate a novel technique that reconstructs the observed time series and incorporates driving forces. Furthermore, to illustrate and test the technique, we consider a couple of predictive experiments using ideal time series provided by the logistic and Lorenz systems with specific driving forces. The preliminary results show this approach can improve prediction proficiency to some extent, and the external forces play a similar role to that of state variables.  相似文献   
516.
Reef and oolitic gas reservoirs in the Permian Changxing and Triassic Feixianguan formations have been discovered in both the Luojiazhai-Puguang and Longgang areas of the Sichuan Basin, but the accumulation scale, abundance and distribution patterns differ greatly. In fact, the two areas have more differences than they have similarities. Similarities include: (1) the lithology, properties and types of porosity of the reef and oolitic reservoirs are primarily consistent in the two areas; (2) well-developed regional caprocks that seal the fluid system; and (3) accumulation process histories, with liquid hydrocarbon charging at an early stage, cracking into gas at a high to over-mature stage, adjustment of gas reservoirs at an uplifting stage, and final reservoir generation at a late stage. Differences include: (1) gas accumulations in the Luojiazhai-Puguang area that are dominated by oil-type cracked gas, with multiple and sufficient gas sources, contrasting with gas accumulations in the Longgang area that are dominated by coal-sourced gas with insufficient gas sources; (2) heterogeneity and horizontal diversity of reservoirs in the Longgang area that are stronger than in the Luojiazhai-Puguang area; and (3) the development of deep and large faults in the Luojiazhai-Puguang area that link source, reservoir and migration pathways, contrasting with poorly developed faults in Longgang area, where laterally variable fractures are the major migration pathway. Because of these differences, abundant large-scale structurally-controlled gas accumulations are developed in the Luojiazhai-Puguang area, whereas lithology plays a more important role in gas accumulation in the Longgang area where accumulations are smaller-scale and have lower gas-bearing abundance. We suggest that future exploration for reef and oolitic gas accumulations should be strengthened in NE Sichuan and NW Sichuan Jiulongshan. In particular, the transitional zone between Longgang and Kaijiang-Liangping Bay has the best potential for new discoveries.  相似文献   
517.
在广义Lebesgue空间Lp(x)(Ω)和广义Sobolev空间W1,p(x)(Ω)的基本理论体系的基础上得到p(x)-Laplace方程有非平凡解的一个充分条件.  相似文献   
518.
The diversity of GISs and the wide-spread availability of WWW have led to an increasing amount of research on integrating a variety of heterogeneous and autonomous GISs in a cooperative environment to construct a new generation of GIS characterizing in open architecture, distributed computation, interoperability, and extensibility. Our on-going research project MADGIS (Mobile Agent based Distributed Geographic Information System) is reported, in which we propose the architecture of MADGIS to meet the requirements of integrating distributed GIS applications under Internet environment. We first describe the architecture of MADGIS, and detailed discussions focusing on the structure of client site, server site and mobile agent in MADGIS. Then we explore key techniques for MADGIS implementation.  相似文献   
519.
耐水复合石膏的研制   总被引:2,自引:1,他引:1  
文中介绍了以β半水石膏为主要成分,通过添加部分工业固体废弃物和几种化学材料研制耐水复合石膏的过程,并对产品性能进行了数据测试和分析。  相似文献   
520.
《永乐大典》残卷中所载的诗歌选本《诗海绘章》是一部由南宋人编选的唐宋诗合选本,其中某些诗人未见于《全宋诗》,某些作品《全宋诗》亦失收,因而具有一定的辑佚价值。从文学史来看,其保存的资料丰富了文学史的叙述,也印证了前人的记载,在一定程度上有利于恢复文学史的原生态。  相似文献   
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