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91.
The emergence of B2B electronic markets has greatly changed the relative bargaining power of buyers and sellers.We study the equilibrium market structure in a buyer's market.We find that buyer-controlled B2B markets and neutral B2B markets have different equilibrium structures,and the emergence of B2B markets will increase social welfare,but its effect on buyers and sellers will be different:B2B markets increase the consumer surplus of the end market,but their effects on buyer and seller profits are moderated by the relative bargaining power of buyers and sellers.The profits of the side with much weaker bargaining power will decrease due to the introduction of B2B markets.  相似文献   
92.
狼群算法(wolf pack algorithm, WPA)源于狼群在捕食及其猎物分配中所体现的群体智能,已被成功应用于复杂函数求解。在此基础上,通过定义运动算子,对人工狼位置、步长和智能行为重新进行二进制编码设计,提出了一种解决离散空间组合优化问题的二进制狼群算法(binary wolf pack algorithm, BWPA)。该算法保留了狼群算法基于职责分工的协作式搜索特性,选取离散空间的经典问题--0-1背包问题进行仿真实验,具体通过10组经典的背包问题算例和BWPA算法与经典的二进制粒子群算法、贪婪遗传算法、量子遗传算法在求解3组高维背包问题时的对比计算,例证了算法具有相对更好的稳定性和全局寻优能力。  相似文献   
93.
支持风险投资的政策体系和制度设计研究   总被引:1,自引:0,他引:1  
风险投资产业的蓬勃发展,需要政府部门的大力支持和推进。首先对现有国内外支持风险投资的政策进行了分析和评价,进而探讨了促进风险投资的制度设计。通过整合一系列的资源要素,形成系统化的制度环境,我国未来的风险投资产业将能够获得长足的发展。  相似文献   
94.
高速旋转丝表面纳米化是一种新型的表面纳米化方法,本文对316L不锈钢表面进行纳米化处理,测定残余应力在材料内部的分布.通过分析、对比实验数据,表面纳米化处理方法,能够在材料内部引入大量残余压应力,提升材料的力学性能.  相似文献   
95.
量子密钥分发和量子隐形传态不断取得的新突破,使量子通信实用化问题日益成为关注的焦点。本文简析了量子通信研究的发展历程,并对量子通信的实用化现状进行了概括:实用化量子密钥分发技术已近在眼前,但量子隐形传态的实用化仍尚需时日。针对认识和理解量子通信时的典型误区,本文做了简要澄清。根据量子通信实用化发展态势,为我国量子通信的发展提出了4点对策和建议  相似文献   
96.
Chen  Haitao  Song  Shenmin 《系统科学与复杂性》2019,32(6):1597-1629
This paper addresses the attitude tracking control problem of a rigid spacecraft in the presence of the modeling uncertainty, external disturbance, and saturated control input by designing two robust attitude tracking controllers. The basic controller is formulated using an integral sliding mode surface which is continuous and provides an asymptotic convergence rate for the closed-loop system. In this case, only the external disturbance with the prior information is considered. Then, to provide a finite time convergence rate and further improve the robustness of the control system under the unknown system uncertainty containing both the modeling uncertainty and external disturbance,a novel integral terminal sliding mode surface(ITSMS) is designed and associated with the continuous adaptive control method. Besides, a command filter is utilized to deal with the immeasurability problem within the proposed ITSMS and an auxiliary system to counteract the input saturation problem. Digital simulations are presented to verify the effectiveness of the proposed controllers.  相似文献   
97.
Aqueous zinc-based batteries (ZBBs) have great potential as commercial energy storage devices.However,the poor cycling stability of zinc anode under high areal ...  相似文献   
98.
Zika virus (ZIKV) belongs to the positive-sense single-stranded RNA-containing Flaviviridae family. Its recent outbreak and association with human diseases (e.g. neurological disorders) have raised global health concerns, and an urgency to develop a therapeutic strategy against ZIKV infection. However, there is no currently approved antiviral against ZIKV. Here we present a comprehensive overview on recent progress in structure–function investigation of ZIKV NS5 protein, the largest non-structural protein of ZIKV, which is responsible for replication of the viral genome, RNA capping and suppression of host interferon responses. Structural comparison of the N-terminal methyltransferase domain and C-terminal RNA-dependent RNA polymerase domain of ZIKV NS5 with their counterparts from related viruses provides mechanistic insights into ZIKV NS5-mediated RNA replication, and identifies residues critical for its enzymatic activities. Finally, a collection of recently identified small molecule inhibitors against ZIKV NS5 or its closely related flavivirus homologues are also discussed.  相似文献   
99.
We present the first analysis of the human proteome with regard to interactions between proteins. We also compare the human interactome with the available interaction datasets from yeast (Saccharomyces cerevisiae), worm (Caenorhabditis elegans) and fly (Drosophila melanogaster). Of >70,000 binary interactions, only 42 were common to human, worm and fly, and only 16 were common to all four datasets. An additional 36 interactions were common to fly and worm but were not observed in humans, although a coimmunoprecipitation assay showed that 9 of the interactions do occur in humans. A re-examination of the connectivity of essential genes in yeast and humans indicated that the available data do not support the presumption that the number of interaction partners can accurately predict whether a gene is essential. Finally, we found that proteins encoded by genes mutated in inherited genetic disorders are likely to interact with proteins known to cause similar disorders, suggesting the existence of disease subnetworks. The human interaction map constructed from our analysis should facilitate an integrative systems biology approach to elucidating the cellular networks that contribute to health and disease states.  相似文献   
100.
Sung LY  Gao S  Shen H  Yu H  Song Y  Smith SL  Chang CC  Inoue K  Kuo L  Lian J  Li A  Tian XC  Tuck DP  Weissman SM  Yang X  Cheng T 《Nature genetics》2006,38(11):1323-1328
Since the creation of Dolly via somatic cell nuclear transfer (SCNT), more than a dozen species of mammals have been cloned using this technology. One hypothesis for the limited success of cloning via SCNT (1%-5%) is that the clones are likely to be derived from adult stem cells. Support for this hypothesis comes from the findings that the reproductive cloning efficiency for embryonic stem cells is five to ten times higher than that for somatic cells as donors and that cloned pups cannot be produced directly from cloned embryos derived from differentiated B and T cells or neuronal cells. The question remains as to whether SCNT-derived animal clones can be derived from truly differentiated somatic cells. We tested this hypothesis with mouse hematopoietic cells at different differentiation stages: hematopoietic stem cells, progenitor cells and granulocytes. We found that cloning efficiency increases over the differentiation hierarchy, and terminally differentiated postmitotic granulocytes yield cloned pups with the greatest cloning efficiency.  相似文献   
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