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991.
Eutrophication, which is the enrichment of a water mass with inorganic and organic nutrients that support plant growth, is a key factor in stimulating phytoplankton growth. In this study, we determined the effects of various nitrogen sources, different nitrogen concentrations in the culture medium, and two culture methods on the growth of the green alga, Enteromorpha prolifera. The relationship between the specific growth rate of E. prolifera and NO3--N concentration was consistent with that estimated using the Monod equation (R2 = 0.9713, P < 0.01). In the NO3--N medium, the maximum specific growth rate was calculated to be 0.1634/d and the semi-saturation constant was calculated to be 16.86 μmol/L. Our results show that E. prolifera can effectively utilize NH4+-N, NO3--N, and NO2--N and urea-N in the range of 5 to 50 μmol/L. NH4+-N was preferentially assimilated by E. prolifera, and urea-N was favorable for long-term growth.  相似文献   
992.
The availability of three dissolved organic phosphorus (DOP) compounds as nutrient sources for experimentalcultare of three algae was studied. Results indicated that these compounds could be utilized byalgae, and that dissolved inorganic phosphorus (DIP) was first to be uptaken when various forms ofphosphorus (DIP and DOP) co-existed. Dicrateria zhanjiangensis' uptake of sodium glycerophosphatewas faster than that of D-ribose-5-phosphate. The increase of sodium glycerphosphate had little effecton the maximum uptake rate(V_(max)) of Chlorella sp., but increased the semisaturation constant(K_s) remarkably;the photosynthesis rates(PR) of Dicrateria zhanjiangensis and Chlorella sp. were rarely affected byusing various forms of phosphorus in the culture experiments. The possible DOP pathways utilizedby algae are discussed.  相似文献   
993.
Feminist post-structuralist theory, feminist empiricism, and field practice can all contribute to insights on the value of quantitative and qualitative methods in feminist geographical research. A political ecology study of gendered interests in a social forestry program in the Dominican Republic illustrates the methodological dilemmas and potentials of feminist research on environmental change. The study combined qualitative and quantitative data collection and analytical techniques. Examples from the case study address three methodological questions in feminist geography: (1) Should identity or affinity be the basis for situating ourselves and the subjects of our research? (2) How can we reconcile multiple subjectivities and quantitative methods in the quest for objectivity? and (3) Can we combine traditional positivist methods with participatory mapping and oral histories? The paper draws on theoretical literature as well as field experience to answer these questions.  相似文献   
994.
While women own 25% of the acres rented out for farming, little has been done in terms of federal policy that focuses on these women. In this policy analysis, we detail how (1) lack of data on these women landowners and (2) the invisibility of these women to federal natural resource and agricultural agency staff contribute to women nonoperating landowners (WNOLs) not being on the federal policy radar. We discuss how the persistence of these factors continues to marginalize WNOLs in federal agricultural policy, despite the mandate of U.S. Department of Agriculture (USDA) agencies to be serving underserved populations such as WNOLs. Our study findings clearly illustrate a critical point: federal agricultural/conservation agencies are not fulfilling their mandate to reach WNOLs. Using data from USDA Production Regions in the United States, we detail how WNOLs are marginalized and provide specific policy recommendations to allow for intentional inclusion of these women.  相似文献   
995.
日常活动视角下居民健康影响的性别差异——以广州为例   总被引:2,自引:1,他引:1  
中国城市化转型背景下,居民的公共健康成为城市地理研究的一个热点。越来越多研究关注健康的性别差异,但基于日常活动视角分析居民健康的影响因素和路径的性别差异研究较为缺乏。因此,作者尝试通过构建结构方程模型探讨不同性别群体居民属性、建成环境、日常活动对健康影响的差异。研究发现:全职男性、全职女性与非全职女性的自评健康存在显著差异,得分依次降低;健康影响因素和影响路径存在性别差异,女性日常活动受到更多约束,其健康更大程度受所住社区周边建成环境和日常活动的影响;女性亚群体之间的健康及影响路径也存在差异;在考虑居民健康性别差异的同时,需要重视就业状况对健康的影响。日常活动视角能揭示居民属性和建成环境对健康影响的路径,有助于理解居民健康影响的性别差异。本文拓宽了健康影响因素的研究框架,对转型背景下改善建成环境,减少日常活动约束,关注健康的性别差异具有重要的现实意义。  相似文献   
996.
红酵母是海洋酵母中的常见种类,在水产养殖中常作为微生态制剂。本实验以第22次南极考察从海冰中分离的红酵母AN5为研究对象,对酵母菌的发酵生长条件进行了优化,结果表明,红酵母培养的最佳碳源和氮源分别为2%的糖蜜和0.5%的酵母粉,最适装液量为50 m L/250 mL,摇瓶转速为140 r·min~(–1),培养基初始pH=3.0,20℃下可获得最佳培养,此时酵母发酵密度可达5.81×10~7 cells·mL~(–1)。发酵后测得酵母中水分含量为69.15%,干酵母蛋白质含量为42.00%,多糖含量为32.08%,脂肪含量为0.39%。在幼参养殖过程中以0.3 g(湿重)·m~(–3)水体的用量投喂极地红酵母,养殖2个月后,与对照相比,幼参体内水分和脂肪含量基本没有变化,而蛋白质和多糖含量明显升高。因此,极地红酵母可大量发酵生产,作为微生态制剂应用于海参的养殖中。  相似文献   
997.
罗秋菊  丁绍莲  潘珂 《地理研究》2018,37(9):1762-1774
伴随着地理学的文化转向以及“身体”“情感”视角的引入,饮食文化的空间问题开始引发人文地理学界的关注。借助身份建构过程模型理论(identity process theory, IPT),依托对38位广州本地人的深度访谈,阐释外来饮食文化对其身份建构过程的影响及代际差异。研究发现,外来饮食文化的涌入引发了老一辈广州人多重的身份危机感,激发他们投身于地方传统饮食文化复兴实践,以对传统的忠诚和坚守来建构其地方身份。而自幼就被外来及本土饮食文化共同包围的年轻人则善于在不同情境下采纳不同文化态度和策略来建构其地方身份,缓解身份危机。该代际差异折射出饮食文化空间政治结构的轮回,而恰恰是这一空间政治的轮回孕育了地方饮食文化的继替。  相似文献   
998.
Drawing on ethnographic case studies from Madagascar, this research shows that multiple marine conservation projects have institutionalized inequitable access to marine recourses along gendered lines. Despite discursive and institutional shifts toward more “collaborative” and “community-based” conservation programing, there is a deficiency of women’s nominal as well as effective participation in community management organizations. This research shows that conservation organizations’ focus on proximate drivers of marine resource use, or a politics of picking the “low-hanging fruit,” over ultimate drivers such as global commodity chains, places disproportionate emphasis on marine spatial enclosures and restricting specific, and gendered, harvest methods. To address gender bias concerning access to and control over natural resources, we must go beyond the rhetoric of “community involvement” to address gendered inequalities in conservation decision making, and whose interests are served by conservation projects.  相似文献   
999.
Greenspace can have a significant positive effect on improved concentration duration, behaviour in the classroom, and educational and social development for school‐aged children. This paper uses Geographical Information Systems to explore academic achievement and greenspace in New Zealand. Using multivariate linear regression, the association between greenspace exposure and the percentage of children achieving above academic attainment expectations was examined, controlling for gender, ethnicity, and socioeconomic status. Socioeconomic status was the most significant predictor of academic achievement. Weak associations between greenspace, academic achievement, gender, and ethnicity were observed. Unexpectedly, academic achievement negatively correlated with greenspace.  相似文献   
1000.
Thunderstorms are one of the most dangerous convective weather events. Despite the recent advances in prediction of convective storms worldwide, thousands of casualties occur annually. In the present study, the authors highlight specifically, thunderstorm‐related casualties reported in India from 1978–2012. Analysis of long‐term data have revealed about 16 308 casualties resulting from 1381 thunderstorm events with an average of 465 casualties occurring annually. The maximum number of casualties were concentrated in north‐eastern and central north‐eastern states. About 80 per cent of total casualties were recorded in West Bengal (23 per cent), Assam (20 per cent), Orissa (14 per cent), Bihar (13 per cent) and Jharkhand (8 per cent) states. The national casualties rate per million population per year and casualties density standardized by area has been found to be 0.50 and 5.07, respectively. Male casualties were found to be more prominent than female and children casualties, probably due to the larger proportion of males performing their work outdoors. The number of thunderstorm events and casualties was observed to be highest during pre‐monsoon season and lowest during winter. It is believed that the findings from this study will help policy makers to draw strategies to cope with the perils of thunderstorms.  相似文献   
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