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排序方式: 共有1103条查询结果,搜索用时 15 毫秒
61.
为最大程度地降低药品无菌工艺生产中微生物污染的风险,以重组溶葡萄球菌酶粉的生产过程为例,利用休哈特控制图、饼图统计工具、失效模式及影响分析(FMEA)风险工具对生产中操作人员可能引入微生物污染的五个因素(手套、前臂、胸口、前额、口罩)进行了监控和风险分析.试验结果表明,口罩的微生物检测结果最差,手套为污染的高风险因素.经过最差条件干预的培养基模拟灌装试验,验证了以预防为主的微生物质量控制措施可以有效控制无菌灌装生产工艺中人员对药品污染的风险.  相似文献   
62.
Multiple organ dysfunction syndrome (MODS), defined as the presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention, is a cause of high morbidity and mortality in humans and animals. Many advances have been made in understanding the pathophysiology and treatment of this syndrome in human medicine, but much still is unknown. This comparative review will provide information regarding the history and pathophysiology of MODS in humans and discuss how MODS affects each major organ system in animals.  相似文献   
63.
AIM:To investigate whether a consensus oligonucleotide, which contains nuclear factor-kappa B(NF-κB) binding site, decreases TNF production stimulated by lipopolysaccharide(LPS).METHODS:The thiophosphoric acid modified oligonucleotides were transferred into rat peritoneal macrophages directly, TNF content in LPS-stimulated cell culture supernatant was determined by ELISA.RESULTS:Adding the consensus oligonucleotides with NF-κB binding site into macrophages markedly decreased TNF production following LPS stimulation.CONCLUSION:These results show that use of the consensus oligonucleotides with NF-κB binding site, which can combine with NF-κB, can block or decrease TNF production induced by LPS in macrophages.  相似文献   
64.
剪力连接件是保证GFRP混凝土组合梁/板中两种不同材料共同工作的重要构造,设计了矩形肋和T形肋两类GFRP肋式剪力连接件,进行了3组共8个GFRP肋式剪力连接件的推出试验,包括:矩形肋开孔、T形肋开孔、T形肋不开孔3组GFRP肋式剪力连接件,得到了其破坏形态、极限承载力、荷载滑移曲线及荷载应变变化规律,重点研究肋内开孔及肋的截面形式对GFRP肋式剪力连接件受力性能的影响。试验结果表明:GFRP肋式剪力连接件的破坏形态均为混凝土劈裂破坏;对比矩形肋开孔试件,T形肋开孔试件强度高、延性好;对比T形肋不开孔试件,T形肋开孔试件强度与延性均能提高。基于试验结果,建立了考虑肋内开孔及肋截面形式影响的GFRP肋式剪力连接件极限承载力计算公式,拟合得到了GFRP肋式剪力连接件的荷载滑移曲线上升段的理论模型,建立了其抗剪刚度计算公式。  相似文献   
65.
传统边坡可靠度分析往往在岩土参数服从线性Mohr-Coulomb(简称线性M-C)破坏准则的假设条件下进行,并且常常采用极限平衡法或有限元法计算安全系数。然而,岩土介质破坏准则具有一定的非线性。为能更加实际地描述岩土破坏机理和得到严格精确的解,基于非线性Mohr-Coulomb(简称非线性M-C)破坏准则,结合极限分析上限法和蒙特卡洛法,进行边坡可靠度上限分析。当非线性参数m=1时,与等效的线性M-C破坏准则进行对比计算,验证了方法的可行性。同时,将初始粘聚力、内摩擦角arctan(c0/σt)和非线性参数作为随机变量且服从截断正态分布,进行了参数变异性和敏感性影响分析。研究表明:非线性M-C破坏准则下,边坡可靠度随初始粘聚力、内摩擦角arctan(c0/σt)和非线性参数变异性的增大而减小;边坡可靠度随初始粘聚力和内摩擦角arctan(c0/σt)的增大而增大,随非线性参数的增大而减小。  相似文献   
66.
Based on the field data of berthing velocity for the ship (10000t-50000t), the berthing velocities have been numerically simulated by using Monte Carlo method in this paper. After statistical tests, it shows that the maximum values of the berthing velocity follow a Gumber distribution and the probability curves of failure for the means of maximum values are also obtained. The present results have been compared with the ones determined by specification of harbor engineering both at home and abroad.  相似文献   
67.
The aim is to evaluate the seismic properties of ancient timber structure after strengthening and analyze the failure process and corresponding failure state. Based on the hysteretic behavior and energy dissipation principle of the dovetail column-frame strengthened with CFRP and Arches Brackets under the low reversed cyclic loading, the “potential of destruction-resisting” of the two energy-consuming components is obtained. The dissipated energy of each energy-consuming component under the various earthquake conditions is calculated combining with the shaking table test of ancient timber structure. The model of seismic damage evaluation of the two energy-consuming components is established on the basis of the “potential of destruction-resisting” and the dissipated energy. By means of the energy distribution coefficient, the relationship of the failure state between energy-consuming components and overall strengthened structure is discovered, and the model of seismic damage evaluation of the overall structure under the various earthquake conditions is presented. With the derived model of seismic damage evaluation, the failure coefficient of the energy-consuming components and the overall strengthened structure is quantitatively calculated. According to the failure state, the corresponding damage grade of overall strengthened structure is obtained. The results can provide a reliable theoretical basis for predicting the destruction before earthquake and re-reinforcement to the strengthened ancient timber structures after earthquake.  相似文献   
68.
Sandstone is sediment rock composed of many cemented sand particles, and corresponding particle constraint and force bearing capacity are greatly controlled by the cemented property. In order to better reflect the cemented property influencing on the mechanical characteristics of the sandstone, take the oil sandstone reservoir for instance, a numerical model based on 3Dimensional Particle Flow Code (PFC3D) considering the parallel bond model was brought forward to simulate the failure mechanism during shearing process. The sandstone cemented property is modeled based on random mathematics and advanced development of Particle Flow Code (PFC), and the relation of the stress ratio, volume strain, coordination number and bond-broken number and the axial strain is analyzed in detail, especially the contact network evolution indicated the force chain is important to transfer the external force, which verifies the feasibility of the numerical model. Based on the above PFC3D model, a series of researches on changing the cemented radius ratio, parallel bond stiffness and cemented volume of the particles have been done to clearly illuminate the importance of cemented property for the bearing capacity of the sandstone structure, which provides a scientific base for research on the failure mechanism of the sandstone under special conditions. Therefore, the above numerical method is more efficient and applicable for comparatively large scale and complex experiments, and the obtained research results can bring a new thought for the real cemented sandstone to research on its macro-micromechanical response and the structure failure mechanism, and also is significant for the sand production mechanism, sand volume prediction and sand control measures for the sandstone reservoir.  相似文献   
69.
基于对50根弯曲破坏钢筋混凝土圆柱低周反复试验结果的分析,建立了完整滞回环的数学表达式并推导得出等效阻尼比计算模型;以双柱墩桥梁为例,说明了建立桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比关系的方法。研究表明,完整滞回环数学表达式较好地反映了弯曲破坏钢筋混凝土圆柱的滞回特性,得到的等效阻尼比模型计算结果与试验结果符合较好;采用建立的桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比的关系进行pushover分析更能反映实际情况。采用等效阻尼比模型算得的目标位移与基于Rosenblueth模型和Kowalsky模型算得的位移之间存在较大差距。  相似文献   
70.
为了从材料细观非均质角度揭示混凝土强度尺寸效应机理,建立了混凝土细观单元等效非均质力学模型,开展了立方体抗拉、抗压强度尺寸效应细观数值模拟研究。研究结果表明:混凝土强度尺寸效应根源于材料细观非均质性,随着模型尺寸的增加,混凝土材料细观单元弹性模量变异系数增大,材料细观非均质性增强,大尺寸模型内部存在更多的低强度单元或缺陷,导致混凝土立方体抗拉、抗压强度降低,极限应变减小,脆性增大;混凝土损伤破坏由少量集中区域,发散扩展形成多条非贯通的裂纹带;数值模拟结果与尺寸效应实验数据相吻合。  相似文献   
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