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211.
To control the reverse-transformation austenite structure through manipulation of the micro/nanometer grain structure, the influences of cold deformation and annealing parameters on the microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. The samples were first cold-rolled, and then samples deformed to different extents were annealed at different temperatures. The microstructure evolutions were analyzed by optical microscopy, scanning electron microscopy (SEM), magnetic measurements, and X-ray diffraction (XRD); the mechanical properties are also determined by tensile tests. The results showed that the fraction of stain-induced martensite was approximately 72% in the 90% cold-rolled steel. The micro/nanometric microstructure was obtained after reversion annealing at 820-870℃ for 60 s. Nearly 100% reversed austenite was obtained in samples annealed at 850℃, where grains with a diameter ≤ 500 nm accounted for 30% and those with a diameter >0.5 μm accounted for 70%. The micro/nanometer-grain steel exhibited not only a high strength level (approximately 959 MPa) but also a desirable elongation of approximately 45%. 相似文献
212.
Slip rate along the Lijiang-Ninglang fault zone estimated from repeating microearthquakes 总被引:2,自引:0,他引:2
Seismicity and slip rates along the Lijiang-Ninglang fault zone between 1999 and 2006 were investigated with the waveform
data recorded by the Yunnan digital Seismic Network. The relocated seismicity by the double difference method clearly exhibits
different features between the northern and southern segments. More than 76% earthquakes occurred in the southern segment
of the fault near the Lijiang area. The relocated seismicity appears to reflect the crustal velocity structure of the study
area. Using cross-correlation analysis, we identified a total of 92 doublets and 70 multiplets that show high waveform similarity.
Most of these sequences are aperiodic with recurrence intervals varying from a few minutes to hundreds of days. Using two
sequences that occurred regularly over the study period, we obtained a fault slip rate of approximately 5 mm/a at ∼23 km,
in good agreement with geologic and surface GPS measurement.
Supported by National Basic Research Program of China (Grant No. 2004CB418405) and National Natural Science Foundation of
China (Grant No. 40174014) 相似文献
213.
Ying Niu BaiYang Sheng Bo Song LingLing Liu XiuFang Zhang NanMing Zhao YanDao Gong 《科学通报(英文版)》2009,54(3):394-398
The effect of endogenously generated amyloid β on membrane fluidity was investigated in Neural 2a cells stably expressing Swedish mutant amyloid precursor protein (APPswe). Membrane fluidity was studied by fluorescence polarizability using 1,6-Diphenyl-1,3,5-Hexatriene (DPH) as the fluorescence probe. It was found that the membrane fluidity in APPswe cells was significantly higher than that in its wild type counterparts. Alleviating the effect of amyloid β either by γ secretase activity inhibition or by amy... 相似文献
214.
In this study, we simulated and analyzed the monthly variations of stable water isotopes in different reservoirs at Manaus, Brazil, using the Community Land Model (CLM) that incorporates stable isotopic effects as a diagnostic tool for understanding stable water isotopic processes, filling the observational data gaps and predicting hydrometeorological processes. The simulation results show that the δ^18O values in precipitation, vapor and surface runoff have distinct seasonality with the marked negative correlations with corresponding water amount. Compared with the survey results by the International Atomic Energy Agency (IAEA) in co-operation with the World Meteorological Organization (WMO), the simulations by CLM reveal the similar temporal distributions of the δ^18O in precipitation. Moreover, the simulated amount effect between monthly δ^18O and monthly precipitation amount, and MWL (meteoric water line) are all close to the measured values. However, the simulated seasonal difference in the δ^18O in precipitation is distinctly smaller than observed one, and the simulated temporal distribution of the δ^18O in precipitation displays the ideal bimodal seasonality rather than the observed single one. These mismatches are possibly related to the simulation capacity and the veracity in forcing data. 相似文献
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217.
煤利用过程中释放多环芳烃类污染物带来重大环境问题,研究不同变质程度煤中PAHs的含量与分布可为煤利用过程中的PAHs的形成与释放控制提供资料。本文在对淮北煤中PAHs的提取分析的基础上,结合本实验室研究数据,着重分析了不同煤种对可提取多环芳烃含量、分布影响。研究认为煤中碳、氢、氧及其它煤质组分与可提取多环芳烃有着密切的关系。 相似文献
218.
219.
亭南煤矿综放开采矿山压力数值模拟 总被引:2,自引:2,他引:0
为了分析综放工作面顶板断裂、垮落形式,以及工作面支承压力分布及影响区域范围,对亭南煤矿101综放面,分别应用UDEC与FLAC3D软件进行了数值模拟对比分析.结果表明随工作面的推进,直接项出现离层、破断,并在采空区前后煤壁上方基岩出现拉裂缝.当工作面推进到60m左右,老顶出现初次破断,形成初次来压,之后工作面每推进30 m,老项出现周期来压.模拟结果再现了顶板冒落、离层、破断,综放面初次、周期来压及围岩应力集中、重新分布等现象,这些结果与现场矿山压力观测结果基本吻合,为矿压观测提供了直观、准确的数值分析方法. 相似文献
220.
Chong Xu Jun Liao Wen Xie Yang Cheng Guoping Zhu Yonghui Yang Chenglu Chen Limei Tao Liwen Niu Yuzhen Wang 《科学通报(英文版)》2000,45(1):64-70
After the establishment of the transformation conditions ofStreptomyces diastaticus No.7 Strain M1033, the integration plasmid pXW for homologous recombination, which contains a 600 bp fragment of incompleteGI (G138P. G247D) gene, has been constructed in order to realize the stable overexpression of theGI (G138P. G247D) which is valuable for large-scale industrial production. The Gigene’s disruption has been realized by pXW’s
integration into M1033 chromosomes via homologous recombination andGI deficient strain ofStreptomyces M1033 has been obtained. The reliability of introduction of mutation has been proved by analysis of recombinant fragment
and affirmance of existence of the mutation, as well as detection of the stability of the deficient strain. 相似文献