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71.
广义极限平衡理论在地基与边坡稳定分析中的应用 总被引:4,自引:0,他引:4
本文提出了复杂介质广义极限平衡理论,并应用于分析各种复杂地基的极限承载力,各种复杂边坡的稳定安全条件,同时定量地研究了各向异性等因素对地基、边坡稳定性的影响。 相似文献
72.
正A wideband low-noise amplifier(LNA) with ESD protection for a multi-mode receiver is presented.The LNA is fabricated in a 0.18-μm SiGe BiCMOS process,covering the 2.1 to 6 GHz frequency band.After optimized noise modeling and circuit design,the measured results show that the LNA has a 12 dB gain over the entire bandwidth, the input third intercept point(IIP3) is -8 dBm at 6 GHz,and the noise figure is from 2.3 to 3.8 dB in the operating band.The overall power consumption is 8 mW at 2.5 V voltage supply. 相似文献
73.
In this letter, we propose a successive multiuser detector (SMUD) for contention based OFDMA ranging channel compliant to the IEEE 802.16 (WiMAX) standard. A ranging channel consists of a set of subcarriers in specific time slots shared by multiple users, so the multiple access interference (MAI) limits the performance of ranging detectors. Different from existing methods that treat the MAI as noise, the proposed SMUD successively detects the channel paths of active ranging signals and cancels their interference for further detection. This approach significantly suppresses the MAI and improves both user detection and parameter estimation performance. 相似文献
74.
当前,局域网中频繁发生的ARP攻击活动令网络管理者防不胜防。文中探讨了ARP协议和ARP攻击原理,针对ARP攻击数据包的特征,提出了一种基于交换机镜像端口的检测和定位方法。该方法包括抓包、包结构分析和确定映射对比、伪造包判断和定位等几个步骤。利用WinPcap开发包实现了该方法,并在2种不同的局域网环境中对进行了测试,结果表明该方法能够检测到大多数ARP攻击并对攻击主机进行定位,具有一定的实用价值。 相似文献
75.
正如局域网 (LAN)是为了满足企业内多用户互连和资源共享 ,为满足家庭中多种数字设备互连和资源共享 ,家庭电话线网设备 (HomePNA)应运而生。文章叙述了HomePNA通信中所需的技术与应用。 相似文献
76.
Huixia Wu Shengjian Zhang Jiamin Zhang Gang Liu Jianlin Shi Lingxia Zhang Xiangzhi Cui Meiling Ruan Qianjun He Wenbo Bu 《Advanced functional materials》2011,21(10):1850-1862
A novel in situ decomposition/reduction approach is developed to manufacture hollow core, magnetic, and mesoporous double‐shell nanostructures (HMMNSs) via in situ decomposition and reduction of a β‐FeOOH nanorod core and organosilicate‐incorporated silica‐shell precursor. The formed HMMNSs are then aminated by silanization for further covalent conjugation to rhodamine B isothiocyanate (RBITC) and poly(ethylene glycol) (PEG) chains. The resultant RBITC‐grafted and PEGylated nanocomposites (HMMNS–R/Ps) have excellent blood compatibility and very low cytotoxicity towards HeLa and MCF‐7 cells, and can be taken up by cancer cells effectively in a dose‐dependent manner, as confirmed by in vitro flow cytometry, confocal luminescence imaging, and magnetic resonance imaging (MRI) studies. In vivo MRI studies coupled with Prussian blue staining of slides from different organs show that the nanocomposites preferentially accumulate in liver and spleen after intravenous injection, which suggests a potential application of the nanocomposites as MRI contrast agents. Importantly, the HMMNS–R/P nanocomposites show high loading capacity for water‐insoluble anticancer drugs (docetaxel or camptothecin) owing to the presence of a large inner cavity and enhanced surface area and pore volume. Furthermore, the drug‐loaded nanocomposites exhibit greater cytotoxicity than the corresponding free drugs. These results confirm that the HMMNS–R/P nanocomposites are promising candidates for simultaneous bioimaging and drug delivery. 相似文献
77.
78.
传统的数据采集器多采用Inte151系列或Inte196系列的CPU,运算能力差,速度慢,精度低,尤其是浮点运算能力限制了技术指标的进一步提高。有鉴于此,各科研单位及数据采集器产家正积极开发新一代的数据采集器。如采用高性能的嵌入式芯片,或带有数字信号处理功能的芯片等。TI公司的TMS320VC33数字信号处理芯片已能支持高达150MFLOPS的运行速度,是需浮点运算的电子产品应用场合中一种较理想的微处理器件。 相似文献
79.
本文根据复射线分析和场的高斯波束展开,提出了一种计算复杂目标电磁散射特性的简便方法。由于复射线法不受目标形状的限制,因此该方法可用于任意形状的目标。本文以矩形进气道为例,进行了雷达截面分析计算,并将计算值与测试值比较,结果表明这种方法是可行的。 相似文献
80.
Enhanced Physiochemical and Mechanical Performance of Chitosan‐Grafted Graphene Oxide for Superior Osteoinductivity 下载免费PDF全文
Jing Ruan Xiansong Wang Zhang Yu Zi Wang Qing Xie Dandan Zhang Yazhuo Huang Huifang Zhou Xiaoping Bi Caiwen Xiao Ping Gu Xianqun Fan 《Advanced functional materials》2016,26(7):1085-1097
The regeneration of artificial bone substitutes is a potential strategy for repairing bone defects. However, the development of substitutes with appropriate osteoinductivity and physiochemical properties, such as water uptake and retention, mechanical properties, and biodegradation, remains challenging. Therefore, there is a motivation to develop new synthetic grafts that possess good biocompatibility, physiochemical properties, and osteoinductivity. Here, we fabricate a biocompatible scaffold through the covalent crosslinking of graphene oxide (GO) and carboxymethyl chitosan (CMC). The resulting GO‐CMC scaffold shows significant high water retention (44% water loss) compared with unmodified CMC scaffolds (120% water loss) due to a steric hindrance effect. The modulus and hardness of the GO‐CMC scaffold are 2.75‐ and 3.51‐fold higher, respectively, than those of the CMC scaffold. Furthermore, the osteoinductivity of the GO‐CMC scaffold is enhanced due to the π–π stacking interactions of the GO sheets, which result in striking upregulation of osteogenesis‐related genes, including osteopontin, bone sialoprotein, osterix, osteocalcin, and alkaline phosphatase. Finally, the GO‐CMC scaffold exhibits excellent reparative effects in repairing rat calvarial defects via the synergistic effects of GO and bone morphogenetic protein‐2. This study provides new insights for developing bone substitutes for tissue engineering and regenerative medicine. 相似文献