全文获取类型
收费全文 | 1308篇 |
免费 | 47篇 |
国内免费 | 131篇 |
专业分类
系统科学 | 78篇 |
丛书文集 | 43篇 |
教育与普及 | 3篇 |
理论与方法论 | 8篇 |
现状及发展 | 40篇 |
综合类 | 1314篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 22篇 |
2021年 | 18篇 |
2020年 | 21篇 |
2019年 | 18篇 |
2018年 | 18篇 |
2017年 | 25篇 |
2016年 | 27篇 |
2015年 | 44篇 |
2014年 | 65篇 |
2013年 | 55篇 |
2012年 | 77篇 |
2011年 | 74篇 |
2010年 | 59篇 |
2009年 | 63篇 |
2008年 | 75篇 |
2007年 | 104篇 |
2006年 | 109篇 |
2005年 | 96篇 |
2004年 | 81篇 |
2003年 | 63篇 |
2002年 | 67篇 |
2001年 | 60篇 |
2000年 | 49篇 |
1999年 | 36篇 |
1998年 | 24篇 |
1997年 | 12篇 |
1996年 | 18篇 |
1995年 | 19篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 9篇 |
排序方式: 共有1486条查询结果,搜索用时 46 毫秒
1.
2.
F是一个3k元域,x3+ax2+bx+c=0是F上的三次方程。该文证明方程x3+ax2+bx+c=0在F中有一根,或一根与二重根,或三个互异的根,或没有根。 相似文献
3.
计算机基础课教学网站开发和建设方案 总被引:1,自引:0,他引:1
张延红 《浙江万里学院学报》2002,15(1):88-90
文章针对计算机基础所面临的不断变化和持续增长 的需求,提出了计算机基础课教学网站的建设方案,介绍了网站的总体结构和创建网站时所使用的主要工具的方法,以及动态WEB的实现技术。 相似文献
4.
唐兴莉 《首都师范大学学报(自然科学版)》2003,24(4):9-12
借助于数学归纳法建立了含第三对称平均值比的一个不等式 ,并将此结果用于正定矩阵 ,获得了一个有趣的结果 . 相似文献
5.
Support vector machine (SVM), as a novel approach in pattern recognition, has demonstrated a success in face detection and face recognition. In this paper, a face recognition approach based on the SVM classifier with the nearest neighbor classifier (NNC) is proposed. The principal component analysis (PCA) is used to reduce the dimension and extract features. Then one-against-all stratedy is used to train the SVM classifiers. At the testing stage, we propose an al- 相似文献
6.
7.
Sensor networks consisted of low-cost, low-power, multifunctional miniature sensor devices have played an important role in our daily life. Light and humidity monitoring, seismic and animal activity detection, environment and habitat monitoring are the most common applications. However, due to the limited power supply, ordinary query methods and algorithms can not be applied on sensor networks. Queries over sensor networks should be power-aware to guarantee the maximum power savings. The minimal power consumption by avoiding the expensive communication of the redundant sensor nodes is concentrated on. A lot of work have been done to reduce the participated nodes, but none of them have considered the overlapping minimum bounded rectangle (MBR) of sensors which make them impossible to reach the optimization solution. The proposed OMSI-tree and OMR algorithm can efficiently solve this problem by executing a given query only on the sensors involved. Experiments show that there is an obvious improvement compared with TinyDB and other spatial index, adopting the proposed schema and algorithm. 相似文献
8.
A. M. Landolt V. Osterwalder T. A. Landolt 《Cellular and molecular life sciences : CMLS》1985,41(5):640-642
Summary Adenomatous prolactin cells lose 39% of their cytoplasm volume within 7 days after the beginning of bromocriptine treatment. A simultaneous reduction of the rough-surfaced endoplasmic reticulum and the Golgi apparatus occurs. Their membranes are removed by rapid transport along the secretory pathway to the cell surface and to lysosomal destruction.We thank Prof. E. del Pozo, Sandoz Ltd, Basle, for the generous gift of injectable bromocriptine, Prof. E.R. Weibel, Dept. of Anatomy, University of Bern, for his technical advice, Dr U. Helfenstein, Institute of Biostatistics, University of Zürich, for his help in the statistical evaluation of the results and the EMDO-Foundation, Zürich, for financial support. 相似文献
9.
10.
Yu. Yu. Chirkov A. R. Kazarov M. A. Malatsidze A. S. Sobolev 《Cellular and molecular life sciences : CMLS》1985,41(11):1430-1432
Summary In mixed culture of Chinese hamster fibroblatst, clone 431, and transformed murine L fibroblasts, clone B-82, isoproterenol was found to protect only 431 cells against ionizing radiation. It was shown that 431 cells, in contrast to B-82 cells, possess-adrenoreceptors, and the radioprotective effect of isoproterenol can be realized only if this agent interacts with-adrenoreceptors coupled with the cAMP system. Since malignization often causes the disappearance of-adrenergic and other hormone receptors, the combined culturing and irradiation of the cells studied can be regarded as a model of the growth of malignant cells (B-82) among normal tissue cells (431 cells) under conditions of radiation therapy. A possibility of selective protection against radiation damage of normal tissue cells, with retention of the former radiosensitivity of tumor cells, is discussed. 相似文献