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111.
The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite. 相似文献
112.
113.
以聚丙烯酸铵为粉体分散剂,聚乙烯醇和丙烯酸乳液为复合粘结剂,聚乙二醇(PEG600)为增塑剂,制备了Ni-Zn水基流延成型铁氧体浆料。研究了Ni-Zn铁氧体粉体在水中的稳定性,以及粘结剂含量、固相含量对浆料性能、流延薄带性能及薄带压合性能的影响。结果表明:在pH=9.5、分散剂含量(质量分数)为6‰时,Ni-Zn铁氧体粉体在水中具有较好的稳定性;在聚乙烯醇、丙烯酸树脂和固相含量(质量分数)分别达到6.5%、15%和54.5%时,所制Ni-Zn浆料具有较好的流动性,以其制成的20μm薄带则结构致密、附着力及压合较好、无分层;以水性浆料和有机浆料分别制成的1005型号电感(介质膜厚和线圈匝数相同)在100 MHz下测得的阻抗几乎相同,而前者成本却降低了80%左右。 相似文献
114.
文章根据互联网视听节目监测从业人员的工作内容,提出上网行为审计系统的设计并加以实现,系统满足加强互联网信息安全的需求,同时规范上网行为、提高工作效率。系统通过用户准入、上网行为记录、流量控制、终端管理等技术手段,部署了一套完整的上网行为审计系统。本系统旨在解决互联网视听节目监测从业人员访问互联网所衍生的信息安全隐患、工作效率低等问题。 相似文献
115.
《中国邮电高校学报(英文版)》2014
This paper designs and implements the advertising recommending system based on user behavior under mobile Internet. By analyzing the user's online behavior, user profile that includes long-term interests and short-term interests can be obtained. In the end of this paper, the similarity between the behavior clusters and the advertisements is calculated, which is used to rank and select the most appropriate advertisements. The experiments show that the system can push the appropriate advertisements according to the user's different interest 相似文献
116.
The effect of cooling rate on microstructure and creep behavior of bulk, eutectic Sn-3.5Ag solders was studied. The cooling
rate is an important processing variable that significantly affects the microstructure of the solder and therefore determines
its mechanical behavior. Controlled cooling rates were obtained by cooling specimens in different media: water, air, and furnace,
which resulted in cooling rates of 24°C/s, 0.5°C/s, and 0.08°C/s, respectively. The cooling rate decreased the secondary dendrite
arm size and the spacing of the Sn-rich phase, as well as the morphology of Ag3Sn. The Sn-dendrite arm size and spacing were smaller at fast cooling rates, while slower cooling rates yielded a nearly eutectic
microstructure. The morphology of Ag3Sn also changed from relatively spherical, at faster cooling rates, to needlelike for slower cooling. The effect of cooling
rate on creep behavior was studied at 25°C, 60°C, 95°C, and 120°C. Faster cooling rates were found to increase the creep strength
of the solder due to the refinement of the solder microstructure. Stress exponents, n, indicated that dislocation climb was
the controlling mechanism. Activation energies, for all cooling rates, indicated that the dominant diffusional mechanism corresponded
to dislocation pipe diffusion of Sn. Grain boundary sliding (GBS) measurements were conducted, using both scanning electron
microscopy (SEM) and atomic force microscopy (AFM). It was observed that GBS had a very small contribution to the total creep
strain. 相似文献
117.
Beulah Christalin Latha Christudas E. Kirubakaran P. Ranjit Jeba Thangaiah 《Telematics and Informatics》2018,35(3):520-533
This paper presents an evolutionary approach for personalizing learning content for individual learners from a very large database in an e-learning system. The proposed work improves the quality of the self-learning process in an adaptive e-learning system by providing the most suitable content for individual learners. The paper depicts the results of personalizing the learning process by tuning the compatibility level of the learning objects with respect to the learning style of the learner, the complexity level of the learning objects with respect to the knowledge level of the learner and the interactivity level of the learner based on the satisfaction level of the learner during the learning process using a modified form of genetic algorithm named as Compatible Genetic Algorithm (CGA). The proposed work improves the efficiency of the genetic algorithms by forcing compatibility in the learning objects which has not been implemented so far in existing systems. Forcing compatibility into the search space not only helps to reduce the search space but also fills the search space with better chromosomes. The results show improvement in scores of the learners and also in their satisfaction levels. A comparison with the standard algorithms shows improvement in execution time, number of executing generations and fitness values. The results indicate that personalization of content delivery based on behavioral traits of learners leads to better learning. 相似文献
118.
119.
Dynamos是含有复数向量的混沌系统,为了考察Dynamos混沌系统的动力学行为,结合该系统的复数动力学方程,首先将该系统转化为实数动力学方程,并利用Simulink具有的图形可视化和参数易调节的特点,对该系统进行了电路模拟仿真。仿真结果显示,该系统在特定参数下能够表现出混沌行为,并且同一向量下面的两个实变量具有同步的特点,这表明该系统还具有十分丰富的动力学行为。 相似文献
120.
研究了铁基表面镀硅(~50nm 厚)经氮离子束处理(能量为 40ke V,剂量分别为5×1016,1×1017,5×1017cm - 2)后的表面结构和在 1 N H2 S O4 水溶液中的腐蚀行为。 T E M 证明,各试样表面均存在一完整的非晶层;电化学测量和失重实验表明,试样的失重量与浸泡时间满足幂函数规律;经表面处理过的试样,腐蚀电位提高了 30~40m V,腐蚀电流密度下降了 4~6 倍;耐腐蚀性随氮离子剂量的增大而不断提高。文章还结合腐蚀表面的粗糙度(分形维数)讨论了离子注入对表面结构和耐蚀性的影响。 相似文献