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921.
Endosulfan, an organochlorine pesticide, is highly toxic and effective at controlling pests in agriculture, horticulture, and public health programs. In this study, static bioassays were used to evaluate the toxicity of endosulfan to freshwater prawns( Macrobrachium rosenbergii) of various lengths(1.5±0.03,4±0.08, and 7±0.06 cm). Additionally, the activities of peroxidase(POD), acid phosphatase(ACP),alkaline phosphatase, acetylcholinesterase(AChE), and Na + /K +-ATPase were analyzed to refl ect the effects of endosulfan exposure. The 96 h LC 50 of endosulfan for prawns 1.5, 4, and 7 cm long were 1.86, 4.53,and 6.09μg/L, respectively, improved tolerance to endosulfan with growth. The POD activities of test organisms exposed to low concentrations of endosulfan were inhibited, indicating the presence of oxygen damaged tissue. Moreover, a notable decrease in AChE activity was observed due to overstimulation of neurotransmission, which might result in abnormal behavior. The effect caused by endosulfan on phosphatase production in the hepatopancreas of prawns 1.5, 4, and 7 cm long was different because the ability of nonspecifi c immune regulation increased with growth. The 96 h LC 50 values obtained in this study could be used in the formulation of water-quality criteria in China. Moreover, the changes in enzymes activities of M. rosenbergii under stress of endosulfan could be applied in the establishment of early warning indicators for bio-safety. 相似文献
922.
Small heat shock proteins encompass a widespread but diverse class of proteins,which play key roles in protecting organisms from various stressors.In the present study,the full-length cDNAs of two small heat shock proteins(MgsHSP22 and MgsHSP24.1)were cloned from Mytilus galloprovincialis,which encoded peptides of 181 and 247 amino acids,respectively.Both MgsHSP22 and MgsHSP24.1 were detected in all tissues examined by real-time PCR,with the highest expression being observed in muscle and gonad tissues.The real-time PCR results revealed that Cd signifi cantly inhibited MgsHSP22 expression at 24 h and MgsHSP24.1 at 24 and 48 h under 5 μg/L Cd 2 + exposure.MgsHSP24.1 expression was also signifi cantly inhibited after 50 μg/L Cd 2+ exposure for 48 h.With regard to antioxidant enzymes,increased GPx and CAT activity were detected under Cd 2+ stress(5 and 50 μg/L),while no signifi cant difference in SOD activity was observed throughout the experiment.Overall,both MgsHsps and antioxidant enzymes revealed their potential as Cd stress biomarkers in M.galloprovincialis. 相似文献
923.
Using the wave model WAVEWATCH III(WW3), we simulated the generation and propagation of typhoon waves in the South China Sea and adjacent areas during the passage of typhoon Nesat(2011). In the domain 100°–145°E and 0°–35°N, the model was forced by the cross-calibrated multi-platform(CCMP) wind fi elds of September 15 to October 5, 2011. We then validated the simulation results against wave radar data observed from an oil platform and altimeter data from the Jason-2 satellite. The simulated waves were characterized by fi ve points along track using the Spectrum Integration Method(SIM) and the Spectrum Partitioning Method(SPM), by which wind sea and swell components of the 1D and 2D wave spectra are separated. There was reasonable agreement between the model results and observations, although the WW3 wave model may underestimate swell wave height. Signifi cant wave heights are large along the typhoon track and are noticeably greater on the right of the track than on the left. Swells from the east are largely unable to enter the South China Sea because of the obstruction due to the Philippine Islands. During the initial stage and later period of the typhoon, swells at the fi ve points were generated by the propagation of waves that were created by typhoons Haitang and Nalgae. Of the two methods, the 2D SPM method is more accurate than the 1D SIM which overestimates the separation frequency under low winds, but the SIM method is more convenient because it does not require wind speed and wave direction. When the typhoon left the area, the wind sea fractions decreased rapidly. Under similar wind conditions, the points located in the South China Sea are affected less than those points situated in the open sea because of the infl uence of the complex internal topography of the South China Sea. The results reveal the characteristic wind sea and swell features of the South China Sea and adjacent areas in response to typhoon Nesat, and provide a reference for swell forecasting and offshore structural designs. 相似文献
924.
XU Weihua Andrés VIA QI Zengxiang OUYANG Zhiyun LIU Jianguo LIU Wei WAN Hui 《中国地理科学(英文版)》2014,24(1):60-70
Many nature reserves are established to protect the habitat needs of particular endangered species of interest but their effec-tiveness for protecting other species is questionable.In this study,this effectiveness was evaluated in a nature reserve network located in the Qinling Mountains,Shaanxi Province,China.The network of reserves was established mainly for the conservation of the giant panda,a species considered as a surrogate for the conservation of many other endangered species in the region.The habitat suitability of nine protected species,including the giant panda,was modeled by using Maximum Entropy(MAXENT) and their spatial congruence was analyzed.Habitat suitability of these species was also overlapped with nature reserve boundaries and their management zones(i.e.,core,buffer and experimental zones).Results show that in general the habitat of the giant panda constitutes a reasonable surrogate of the habitat of other protected species,and giant panda reserves protect a relatively high proportion of the habitat of other protected species.Therefore,giant panda habitat conservation also allows the conservation of the habitat of other protected species in the region.However,a large area of suitable habitat was excluded from the nature reserve network.In addition,four species exhibited a low proportion of highly suitable habitat inside the core zones of nature reserves.It suggests that a high proportion of suitable habitat of protected species not targeted for conservation is located in the experimental and buffer zones,thus,is being affected by human activities.To increase their conservation effectiveness,nature reserves and their management zones need to be re-examined in order to include suitable habitat of more endangered species.The procedures described in this study can be easily implemented for the conservation of many endangered species not only in China but in many other parts of the world. 相似文献
925.
龙虎斑鱼肌肉营养成分分析 总被引:2,自引:0,他引:2
对龙虎斑鱼的肌肉进行营养成分分析和肉质评价,结果表明,龙虎斑鱼新鲜肌肉中粗脂肪质量分数4.18%,粗蛋白质量分数17.05%,粗灰分质量分数1.24%,水分质量分数80.19%.肌肉蛋白质中共检测出氨基酸种类有17 种,占新鲜肌肉样品的质量分数为17.88%;7 种必需氨基酸(EAA)占新鲜肌肉样品的质量分数为7.79%,占氨基酸总量的43.57%;4 种鲜味氨基酸(DAA)占新鲜肌肉样品的质量分数为6.17%,占氨基酸总量的34.51%;必需氨基酸指数(EAAI)为101.35,其氨基酸组成比例符合FAO/WHO 标准.新鲜肌肉中共检测出脂肪酸种类有14 种.其中7 种饱和脂肪酸(SFA)占总脂肪酸的质量分数为47.29%;4 种单不饱和脂肪酸(MUFA)占总脂肪酸的质量分数为18.86%;3 种多不饱和脂肪酸(PUFA)占总脂肪酸的质量分数为33.86%,DHA 质量分数占脂肪酸总量的30.24%.龙虎斑鱼营养价值较高,海鲜味浓郁. 相似文献
926.
利用WRF(weather research and forecasting)模式模拟资料对2008年06号台风“风神”进行诊断分析,采用准地转PV-ω方程对台风外围中尺度对流系统较强的6月20日10时(世界时)的资料进行分析.通过PV-ω方程诊断了潜热、摩擦及干动力过程对台风次级环流的作用,结果显示潜热强迫产生的次级环流最强,摩擦强迫主要集中在边界层,而干动力过程则在台风中心附近产生影响.加入摩擦、潜热得到的准平衡流场能够描述70%左右的台风环流.环境垂直切变在台风中心附近强迫产生横向次级环流的垂直切变与环境垂直切变相反,次级环流会使得台风一侧的上升气流减弱而另一侧上升气流增强,从而使得台风不对称增强.同时,发现垂直切变可能在其最大垂直切变方向右侧激发台风外围中尺度系统.通过构造理想的准平衡的台风及叠加在其上的中尺度系统环流,选择不同的切变和环境平均气流,发现增大切变会使得强迫次级环流增强,而增大环境平均气流不一定能够使得强迫次级环流增大,反而可能使得强迫次级环流减弱.通过诊断发现由切变强迫次级环流造成的中尺度对流系统上方扰动可能是中尺度对流系统持续存在的原因. 相似文献
927.
928.
2001-2011年西宁市空气质量特征及其与气象条件的关系 总被引:2,自引:0,他引:2
利用2001-2011年西宁市城市空气质量日报资料,研究西宁市区域性污染特征,并结合气象资料对空气质量变化特征和影响因素进行了分析。结果表明:西宁市空气污染以可吸入颗粒物为主要污染物,空气质量状况以优和良居多;空气质量季节变化特征明显,春季空气质量最差,其次是冬季和秋季,夏季空气质量最好,冬春季空气质量不稳定,夏秋季空气质量较稳定; 空气质量年变化幅度大,供暖期API指数明显高于非供暖期;沙尘影响指数呈现下降趋势;从年际变化来看,空气质量已经有了明显改善;气象要素对大气污染物有制约关系,其中起主要作用气象因子为沙尘日数、降水量、相对湿度和气温; 可吸入颗粒物长距离输送是西宁市冬春季重污染现象的主要原因,来源于新疆、甘肃西北部、内蒙古中西部及本省西北部的柴达木盆地。 相似文献
929.
?????????EEMD??GPS???????????????????????????????????????徭??????????????????????????????????????????????????????????????????????й?????CORS??????????????????????????飬?????????????????????????????????????????????????????????????????????????? 相似文献
930.
???????GPS???????????????о???????????GPS???????????????????????о??????????????????????????????????????????????????????У???????????????????????е????????????????????????????????????????? 相似文献