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121.
开沟播种施肥综合作业机设计 总被引:1,自引:0,他引:1
农业联合作业技术是在农业生产中将多种机具、多道工序在1台机具上得以实现的农业作业技术,是现代化农业的发展之路,是减少资源浪费和降低成本的重要方式。联合作业机具有效率高、作业成本低、农机利用率高和节约能源等多种优点,目前国内使用的联合作业机主要适用于我国北方旱作耕地,适用南方的机型较少。为此,本文给出了旋耕灭茬施肥播种联合作业机的设计方案,可适合于小麦和油菜的施肥播种。 相似文献
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针对特殊干旱年山湖水库水资源优化调度问题,提出了单座年调节水库与补库泵站、调水泵站联合运行的“一库两站”系统水资源优化调度模型.模型以年内各阶段受水区缺水量平方和最小为目标函数,各阶段水库的供水量与外调水量为决策变量,水库年可供水量、调水泵站年提水量、库站联合运行调度准则为约束条件,采用动态规划逐次逼近法求解,获得了水库最优的供水量过程和弃水量过程、补库泵站最优的补水量过程以及调水泵站最优的提水量过程.结果表明:山湖水库“一库两站”系统水资源优化调度可将系统缺水量从16万m3减小至8.6万m3,而水库弃水量从84.1万m3减小至0,泵站补水量从2 190万m3减小至2 140万m3,外调水量从380万m3增加至390万m3.该成果可为采用类似“一库两站”系统供水灌区的运行管理提供借鉴和参考. 相似文献
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针对中俄东线天然气管道工程北段的冬季防腐补口施工要求,通过材料低温力学性能分析、结构优化设计、低温试验、低温电子元器件优选、机械式温控、加热元件高低温交变及国内外低温补口材料对比分析等综合研究,研制了适用于-40℃低温环境的机械化防腐补口装备,制定了配套的机械化防腐补口工艺和施工方案。工程应用表明:低温机械化防腐补口装备与工艺有效保证了中俄东线试验段及北段管道工程的防腐补口质量和施工效率,日平均补口30道,一次合格率100%。积累了大口径管道低温环境下的防腐补口施工经验,可为中俄东线天然气管道工程中段及同类管道工程的防腐补口施工提供技术支撑。 相似文献
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木构建筑的榫卯结构作为我国传统文化的瑰宝,在现代建筑中应用广泛。笔者通过对现存木构建筑中榫卯的作用以及种类的分析,归纳了木构建筑中的几种常用的榫卯及其应用方式。通过查阅资料以及实地考察,分析了国内外建筑中榫卯的应用方法,归纳出榫卯结构在现代建筑的应用现状与发展前景。从榫卯的材料和结构方面出发,介绍了现阶段榫卯的创新发展现状,结合其在建筑中应用的方法与未来发展方向,提出了榫卯的创新方向及趋势。对榫卯进行应用分析并为未来的发展提供大致的方向,为今后榫卯的再设计奠定坚实的基础,有利于对其进行更好的传承和发展。 相似文献
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M. J. RODRÍGUEZ R. LATORRE O. LÓPEZ‐ALBORS M. SOLER C. AGUIRRE J. M. VÁZQUEZ M. QUEROL A. AGUT 《Equine veterinary journal》2008,40(6):566-571
Reasons for performing study: The equine temporomandibular joint (TMJ) and its surrounding structures can be difficult to investigate in cases with a clinical problem related to the region. Little previous attention has been given either to a computed tomographic (CT) imaging protocol for the joint or an interpretation of the structures displayed in CT images of the normal joint. Objectives: To provide a CT atlas of the normal cross‐sectional anatomy of the equine TMJ using frozen and plastinated sections as anatomical reference. Methods: Eight TMJs from 4 immature pure‐bred Spanish horses were examined by helical CT. Scans were processed with a detailed algorithm to enhance bony and soft tissue. Transverse CT images were reformatted into sagittal and dorsal planes. Transverse, sagittal and dorsal cryosections were then obtained, photographed and plastinated. Relevant anatomic structures were identified in the CT images and corresponding anatomical sections. Results: In the CT images, a bone window provided excellent bone detail, however, the soft tissue components of the TMJ were not as well visualised using a soft tissue window. The articular cartilage was observed as a hyperattenuating stripe over the low attenuated subchondral bone and good delineation was obtained between cortex and medulla. The tympanic and petrous part of the temporal bone (middle and inner ear) and the temporohyoid joint were seen in close proximity to the TMJ. Conclusions: Helical CT provided excellent images of the TMJ bone components to characterise the CT anatomy of the normal joint. Potential relevance: Detailed information is provided that may be used as a reference by equine veterinarians for the CT investigation of the equine TMJ and serve to assist them in the diagnosis of disorders of the TMJ and related structures (middle and inner ear). The study was performed at an immature stage and further studies of mature individuals are required in order to confirm that the clinical interpretation is not affected by changes occurring with age. 相似文献
127.
Cheetham J Witte TH Rawlinson JJ Soderholm LV Mohammed HO Ducharme NG 《Equine veterinary journal》2008,40(6):584-588
Reasons for performing study: The success of laryngoplasty is limited by abduction loss in the early post operative period. Objective: To determine the efficacy of polymethylmethacrylate (PMMA) in stabilising the cricoarytenoid joint (CAJ) and reducing the force on the laryngoplasty suture. Hypothesis: Injection into the cricoarytenoid joint resists the forces produced by physiological laryngeal air flows and pressures thereby reducing the force experienced by the laryngoplasty suture. Methods: Ten cadaver larynges were collected at necropsy and PMMA was injected into one CAJ at selected random. Each larynx was subjected to physiological conditions with with constant (static) or cycling (dynamic) flow. The specimens were tested sequentially in each of 4 conditions: 1) bilateral full abduction (Control 1); 2) transection of the suture on the side without PMMA; 3) bilateral abduction achieved by replacing the suture (Control 2); and 4) cutting the suture on the PMMA side. Tracheal pressure and flow and pressure in the flow chamber were recorded using pressure and flow transducers. The strain experienced by each suture during bilateral abduction (Controls 1 and 2) was measured. Statistical comparison of the 4 conditions was performed using a mixed effect model with Tukey's post hoc test for multiple comparisons. The strain gauge data were analysed by paired comparison of the regression slopes. Results: In the static and dynamic states, tracheal pressure increased and tracheal flow decreased when the suture on the non‐cement side was cut (P<0.05). There was no significant difference in any outcome measure between PMMA injected into the CAJ and bilaterally abducted specimens (Controls 1 and 2) for either condition. The rate of increase in strain with increasing translaryngeal pressure was significantly less on the suture with PMMA placed in the CAJ (P = 0.03). Conclusions: These data provide strong evidence that injecting PMMA into the CAJ resists the collapsing effect of physiological airflows and pressures in vitro and reduces the force experienced by the laryngoplasty suture during maximal abduction. Potential relevance: Augmentation of prosthetic laryngoplasty with this technique may reduce arytenoid abduction loss in the early post operative period. 相似文献
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