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361.
南极放线菌NJ-F2萃取物的抗菌活性初步研究 总被引:2,自引:0,他引:2
从南极第24次科学考察采集的海泥样品中分离获得放线菌NJ-F2,对NJ-F2发酵液的乙酸乙酯萃取物进行体外抗菌实验,并采用16S rDNA方法对NJ-F2进行系统发育分析.结果表明萃取物对金黄色葡萄球菌和枯草芽孢杆菌的最低抑菌浓度(MIC)、最低杀菌浓度(MBC)分别为0.25 mg/mL,5.0 mg/mL;而对大肠杆菌和产气杆菌的MIC、MBC分别为0.5 mg/mL,5.0 mg/mL,但对真菌没有抗菌作用;16SrDNA分析结果表明NJ-F2为链霉菌属(Streptomyces sp.). 相似文献
362.
363.
不同光生物反应器培养坛紫菜
丝状体的比较研究 总被引:1,自引:0,他引:1
Vegetative cells of Porphyra haitanensis sporophytes were grown in a bubble-column and a draft-tube internal-loop airlift bioreactor at 20℃ with an illuminance of 40μmol photons m-2 s-1 for 20days. The draft-tube internal-loop airlift bioreactor yielded maximum cell density of 4850mg DCW (Dried Cell Weight)/L and higher growth rate of 0.094/d, compared to the bubble-column, 3950mg DCW/L and 0.086/d, respectively. The advantages were related to the more homogeneous fluid dynamic characteristics in the draft-tube internal-loop airlift bioreactor than the bubble-column bioreactor. 相似文献
364.
区域重力大地水准面确定的相对精度估计 总被引:2,自引:1,他引:1
以频域解析方法,研究由地面重力数据、全球住模型确定区域重力大地水准面的相对精度估计.首先由Stokes公式的数值积分推导地面重力数据与球谐系敬的精度关系;再由"移去-恢复"方法的空域截断逼近模式和协方差函数的球谐表达,分别推导内区地面重力数据之误差、外区全球位模型之误差与区域重力大地水准面之相对精度的解析关系;为便于计算,提出将内区地面重力数据和外区全球位模型的频域截断误差合并,再按频段重新划分为两部分:①全球范围--地面重力数据对应频率以上的截断;②外区范围--介于全球位模型最高频率与地面重力数据对应频率之间的截断,以经验阶方差模型分别估计之.模拟计算显示了地面重力数据之精度、分辨率、积分半径和全球位模型之精度、分辨率与区域重力大地水准面之相时精度的具体对应关系.本文研究同样适用于区域重力似大地水准面的确定. 相似文献
365.
Banana is one of the main economic agrotypes in Zhangzhou, Fujian Province. The multi-temporal ENVISAT ASAR data with different
polarization are used to classify the banana fields in this paper. Principal component analysis (PCA) was applied for six
pairs of ASAR dual-polarization data. For its large leaves, banana has high backscatter. So the value of banana fields is
high and shows very bright in the 1st component, which makes it much easier for banana fields extraction. Dual-polarization
data provide more information, and the VV and VH backscatter of banana show different characters with other land covers. Based
on the analysis of the radar signature of banana fields and other land covers and the 1st component, banana fields are classified
using object-oriented classifier. Compared to the field survey data and ASTER data, the accuracy of banana fields in the study
area is 83.5%. It shows that the principal component analysis provides the useful information in SAR images analysis and makes
the extraction of banana fields easier.
Supported by the Program for New Century Excellent Talents in University (NCET-05-0573), Fujian Science and Technology Project
(No.2006I0018), the Science Project of the Education Department of Fujian Province(No. 2006F5022). 相似文献
366.
This paper systematically studies the statistical diagnosis and hypothesis testing for the semiparametric linear regression model according to the theories and methods of the statistical diagnosis and hypothesis testing for parametric regression model.Several diagnostic measures and the methods for gross error testing are derived.Especially,the global and local influence analysis of the gross error on the parameter X and the nonparameter s are discussed in detail;at the same time,the paper proves that the d... 相似文献
367.
368.
Geochemistry of pore waters from the Xisha Trough, northern South China Sea and their implications for gas hydrates 总被引:2,自引:0,他引:2
Shao-Yong Jiang Tao Yang Lu Ge Jing-Hong Yang Hong-Fei Ling Neng-You Wu Jian Liu Dao-Hua Chen 《Journal of Oceanography》2008,64(3):459-470
This paper reports all available geochemical data on sediments and pore waters from the Xisha Trough on the northern continental
margin of the South China Sea. The methane concentrations in marine sediments display a downhole increasing trend and their
carbon isotopic compositions (δ
13C = −25 to −51‰) indicate a thermogenic origin. Pore water Cl− concentrations show a range from 537 to 730 mM, and the high Cl− samples also have higher concentrations of Br−, Na+, K+, and Mg2+, implying mixing between normal seawater and brine in the basin. The SO4
2− concentrations of pore waters vary from 19.9 to 36.8 mM, and show a downhole decreasing trend. Calculated SMI (sulfate-methane
interfaces) depths and sulfate gradients are between 21 and 47 mbsf, and between −0.7 and −1.7 mM/m, respectively, which are
similar to values in gas hydrate locations worldwide and suggest a high methane flux in the basin. Overall, the geochemical
data, together with geological and geophysical evidence, such as the high sedimentation rates, high organic carbon contents,
thick sediment piles, salt and mud diapirs, active faulting, abundant thermogenic gases, and occurrence of huge bottom simulating
reflector (BSR), are suggestive of a favorable condition for occurrence of gas hydrates in this region. 相似文献
369.
Dissolved inorganic carbon (DIC) and its carbon isotopic composition in sediment pore waters from the Shenhu area,northern South China Sea 总被引:2,自引:0,他引:2
Tao Yang Shao-Yong Jiang Jing-Hong Yang Ge Lu Neng-You Wu Jian Liu Dao-Hua Chen 《Journal of Oceanography》2008,64(2):303-310
The Shenhu area is one of the most favorable places for the occurrence of gas hydrates in the northern continental slope of
the South China Sea. Pore water samples were collected in two piston cores (SH-A and SH-B) from this area, and the concentrations
of sulfate and dissolved inorganic carbon (DIC) and its carbon isotopic composition were measured. The data revealed large
DIC variations and very negative δ
13C-DIC values. Two reaction zones, 0–3 mbsf and below 3 mbsf, are identified in the sediment system. At site SH-A, the upper
zone (0–3 mbsf) shows relatively constant sulfate and DIC concentrations and δ
13C-DIC values, possibly due to bioturbation and fluid advection. The lower zone (below 3 mbsf) displays good linear gradients
for sulfate and DIC concentrations, and δ
13C-DIC values. At site SH-B, both zones show linear gradients, but the decreasing gradients for δ
13C-DIC and SO4
2− in the lower zone below 3 mbsf are greater than those from the upper zone, 0–3 mbsf. The calculated sulfate-methane interface
(SMI) depths of the two cores are 10.0 m and 11.1 m, respectively. The depth profiles of both DIC and δ
13C-DIC showed similar characteristics as those in other gas hydrate locations in the world oceans, such as the Blake Ridge.
Overall, our results indicate an anaerobic methane oxidation (AMO) process in the sediments with large methane flux from depth
in the studied area, which might be linked to the formation of gas hydrates in this area. 相似文献
370.