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231.
Fossil leaf impressions and pollen grains comparable to modern Sloanea sp. of Elaeocarpaceae collected from the middle part of the Siwalik sediments (Geabdat Sandstone Formation; Pliocene) in Darjeeling foothills of eastern Himalaya are reported in the present communication. On the basis of macro morphological features, leaf remains are described as a new species Sloanea siwalika sp. nov. This is the first authentic record of the occurrence of leaf and pollen grains comparable to the genus Sloanea L. from the Cenozoic sediments of India and Asia as well. The recovery of this species and other earlier-described evergreen taxa from the same formation, suggests the existence of a tropical, warm and humid climatic conditions during the depositional period. The present study further suggests that after Pliocene the taxon might have shifted from Darjeeling Himalayan region to the adjoining southeast Asian land masses, due to possible climate change caused by post-Pliocene orogenic movement of the Himalaya.  相似文献   
232.
Groundwater is an important source of drinking and irrigation purpose and the greater part of the total populace relies on groundwater for survival. Present study investigates the hydrogeochemistry and groundwater quality of the study area for drinking and irrigation purpose. In this study, total 100 numbers groundwater samples were collected and analyzed using standard methods (APHA, 1995) during pre-monsoon period (May, 2016). In the study area, there is occurrence of mainly Ca+2–Mg+2–HCO3 and Ca+2–Mg+2–SO 4 –2 water type and the dominant cations and anions are Ca>Mg>Na>K>Fe=HCO3>Cl>CO3> SO4>Fe>F>NH3. The Gibbs plot shows that, hydrogeochemistry of ground-water is depending upon rock-water interaction. Present study, indicate that groundwater quality in the study area is suitable for irrigation and drinking purpose except some groundwater sample, which are showing high Nitrate, Iron, Sulphate, Ammonia and Calcium concentration.  相似文献   
233.
Intermontane basin sedimentation occurred during Pliocene-Pleistocene in the Karewa Basin which formed after the continent-continent collision resulting in the formation of Himalayan orogenic belt around Eocene. These are elongated, narrow, thrust bounded basins which have formed during the late stages of orogeny. Situated at a height of 1700–1800 m above sea level, the Karewa basin received sediments because of ponding of a pre-existing river system and the tectonic movements along the Great Himalayan Ranges in the north and the Pir-Panjal ranges in the south along active faults. About 1300 m thick sediments of largely fluvio-lacustrine, glacio-fluvio-lacustrine and eolian origin are exposed having evidences of neotectonically formed structural features such as folds and faults. Folds are more prominent in the Lower Karewa formation (Hirpur Formation) while faults (mostly normal faults) are abundant in the Upper Karewas (Nagum Formation). Drainage in the area varies from dendritic to anastomosing to parallel. Anastomosing drainage suggests sudden decrease in gradient while presence of linear features such as faults and ridges is evident by parallel drainage. Study of morphometric parameters such as stream length (Lsm) and stream length ratios (RL), bifurcation ratio (Rb), drainage density (D), form factor (Rf), circularity ratio (Rc), and elongation ratio (Re) also indicate intense tectonic activity in the recent past.  相似文献   
234.
Climate change adds another dimension of challenges to the growth and sustainability of Indian agriculture. The growing exposure to livelihood shocks from climate variability/change and limited resource base of the rural community to adapt has reinforced the need to mainstream climate adaptation planning into developmental landscape. However, a better understanding of micro-level perceptions is imperative for effective and informed planning at the macro-level. In this paper, the grass-root level perspectives on climate change impacts and adaptation decisions were elicited at farm level in the Moga district of Punjab and Mahbubnagar district of Telangana, India. The farmers opined that the climatic variability impacts more than the long-term climate change. They observed change in the quantum, onset and distribution of rainfall, rise in minimum as well as maximum temperature levels, decline in crop yield and ground water depletion. The key socio-economic effects of climate change included decline in farm income, farm unemployment, rural migration and increased indebtedness among farmers. In order to cope with climate variability and change thereon, farmers resorted to adaptation strategies such as use of crop varieties of suitable duration, water conservation techniques, crop insurance and participation in non-farm activities and employment guarantee schemes. Farmers’ adaptation to changing climate was constrained by several technological, socio-economic and institutional barriers. These include limited knowledge on the costs–benefits of adaptation, lack of access to and knowledge of adaptation technologies, lack of financial resources and limited information on weather. Besides, lack of access to input markets, inadequate farm labour and smaller farm size were the other constraints. Further, on the basis of the grass-root elicitation a ‘Need-Based Adaptation’ planning incorporating farmers’ perceptions on climate change impacts, constraints in the adoption of adaptation strategies and plausible adaptation options were linked with the most suitable ongoing programmatic interventions of the Government of India. The study concluded that micro-level needs and constraints for various adaptation strategies and interventions should be an integral part of the programme development, implementation and evaluation in the entire developmental paradigm.  相似文献   
235.
Emerging environmental issues related to heavy metal contamination in rice draw great concern about the soil quality of paddy farming lands irrigated with groundwater. Investigating the functioning of soil microorganisms exposed to heavy metal contamination is imperative for agricultural soil manipulations. The current study accentuates the influence of heavy metals on microbial activity and community composition in arable soil of West Bengal State of India. The result revealed that the fertility indicators (activity of all soil enzymes) and growth-limiting factors (soil N and P) were negatively correlated with the heavy metal stress except the soil total organic content which demonstrated significant positive correlation with the heavy metals. In case of functional diversity of soil, all the considered diversity indices exhibited no specific pattern along with the availability of heavy metals. Further, despite the heavy metal contamination, we observed a very complex and indifferent pattern of bacterial community composition along the heavy metal contamination sites. Overall, we found that γ-Proteobacteria had been the most abundant bacterial community followed by Actinobacteria, Firmicutes, β-Proteobacteria and α-Proteobacteria. Commemorating all the results, we can infer that arsenic and other heavy metal contamination is deteriorating the soil quality and hence warrants immediate attention of concerned soil scientist and agronomists.  相似文献   
236.
Biochar has been considered a safe soil additive to enhance soil fertility and agronomic traits of different crops. This study was conducted to explore the impacts of sugarcane waste straw biochar on soil characteristics and some agronomic traits of okra. The experiment was carried out with four treatments, i.e., control, sugarcane waste straw biochar (10 ton ha?1), farmyard manure (FYM, 10 ton ha?1), and chemical fertilizers (NPK; 120:100:80 kg ha?1) having three replications of each treatment. Soil samples were tested for texture, bulk density, particle density, pH, electrical conductivity (EC), organic matter content, nitrate nitrogen (NO3-N), and extractable-P. The sugarcane waste straw biochar was characterized for plant major nutrient elements. The impact of various treatments was observed on soils and agronomic traits of okra like plant height, fruit size, fruit length, and yield of okra. Results revealed that sugarcane waste straw biochar expressed higher EC value and noticeable amounts of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and magnesium (Mg). The sugarcane waste straw biochar, in comparison with FYM and NPK, significantly improved the NO3-N, extractable-P, OM and EC of the calcareous soil, and reduced the soil bulk density. Furthermore, plant growth and yield parameters were significantly improved under biochar application over the control, FYM and NPK. Overall, sugarcane waste straw biochar proved to be a good alternative to conventional organic and inorganic fertilizers under calcareous soil conditions.  相似文献   
237.
Conglomerate bodies are wide spread in the Lower Coniacian carbonate of the southern of Tunisia. This paper presents an examination of the stratigraphic architecture of these Coniacian conglomerates. It aims to the understanding of the processes leading to their genesis and the relationship and context with the late Cretaceous sedimentation. These conglomerates are related to the incision of Aptian palaeovalleys in a carbonate platform in an extensional setting. The sedimentary analysis and the geometry of these bodies show that the Cretaceous succession in this area are formed by eight facies within four facies associations, representing a series of distinct depositional environments ranging from alluvial plain to the open marine environment. The sedimentary analysis allowed the recognization of elementary sequence which start with the conglomerate bodies corresponding to the incised valley fills.  相似文献   
238.
During the Mesozoic and Cenozoic rifting, the Pelagian Sea recorded the consequences of the African and European plate’s rapprochement. The interpretation of surface and subsurface data that is the 2D seismic reflection and petroleum well data show new ideas on the geodynamic evolution and halokinesis of the Jeffara basin during the Mesozoic and Cenozoic period. Seismic lines interpretations of the subsurface mainly reveal normal syn-sedimentary NW-SE faulting and where the Jeffara fault seems to be the major play. This syn-sedimentary faulting induced horst and graben structures materialized by major sedimentary sequences thicknesses as well as depths variations on the seismic profiles from the Jeffara fault zone overall towards the East of Jeffara basin. After the Hercynian event of the Permian - Carboniferous age, a general extension took place, which gave rise to the Tethyan opening. This extension has favored the individualization of the Jeffara basin in the South East of Tunisia, characterized by a structuring in Horst and Graben with a Permian carbonate subsidence. During the Triassic - Middle Jurassic period, the Jeffara basin is marked by a pronounced subsidence of essentially evaporate sedimentation accompanied by the birth of normal syn-sedimentary NW-SE faults following an NE-SW extension. This subsidence continuing during the Upper Jurassic period, the accentuation of which is towards the NE of the study zone at the Jerba and El Bibane sub-basin with a dominance of bioclastic limestone and dolomites sedimentation in the same extensive NE-SW direction, during this period, the Jeffara basin was characterized by a beginning of salt activity indicated by the appearance of salt nuclei at the base of the preexisting NW-SE normal faults. During the Lower Cretaceous, we are witnessing an individualization of salt complexes in the SE of the study area at Rass Ajil sub-basin, where this reactive diapirism has produced high zones and erosions in the crest above the salt bodies. During the mid Cretaceous period, the Zebbag formation, hatched by the Gattar carbonate bar, recorded a subsidence inversion phenomenon between the three sub-basins Jerba, El Bibane and Rass Ajil sub-basin, and showed the change of movement of the African plate relative to the European plate related to the opening of the North Atlantic and the beginning of the drift towards the North of Africa. This phenomenon is concretized towards the Upper Cretaceous, where we witness a strong subsidence towards the southeastern part of the study area at Rass Ajil sub-basin with sandstone, marl and clay sedimentation under a regional extensive regime and the individualization of high zones at Jerba sub-basin. The salt movements present an active aspect by piercing their cover and inducing rim synclines in the surroundings. The Cenozoic period is characterized by a strong subsidence of sandstone, clays and carbonates along the Jeffara basin, the salt activity shows a passive aspect at the beginning of this period which slows down and eventually stopped at the late Miocene period, thus indicating the probable exhaustion of the source of the salt material.  相似文献   
239.
Pakistan is a developing country existing geographically at a pivoted location between two of the world’s largest pollution emitting countries (China and India) which adds to the severity of environmental issues faced by the country. These concerns include air pollution, climate change, and extreme weather situations prevailing in Pakistan. This increasing air pollution is deteriorating the health, threatening the food security and adding up its share to the already existing global warming. The initial step in devising a wide ranging, multifaceted, economically feasible, and sustainable solution to deal with the severity of this issue is the quantification of the air pollution and greenhouse gas emission in Pakistan. The GAINS model is one of the most comprehensive tools, dealing with the air pollutants and greenhouse gases covered by the Kyoto Protocol. This study has utilized this model to analyze the source-based anthropogenic emissions of air pollutants (NH3 and SO2), volatile organic compounds (VOCs), and greenhouse gases (CH4 and CO2), their impacts and abatement cost, for the duration of 1990–2030, in the Khyber Pakhtunkhwa and Balochistan regions of Pakistan. An overall increasing trend was observed during 1990–2030 for (a) air pollutants: NH3 (223.52–568.87kT/Y); SO2 (50.52–332.95kT/Y), (b) VOCs (121.76–246.81kT/Y), and (c) greenhouse gases: CO2 (7.83–62.45MT/Y) and CH4 (1120-2314kT/Y). The emission inventories created for all greenhouse gases together estimated the increase of 42.37 to 138.57 MTCO2eq. for greenhouse gases over the time duration of 1990–2030.  相似文献   
240.
Geomagnetism and Aeronomy - In this work, the secular variation of noon/midnight geomagnetic observed field has been investigated at Karachi observatory using the data of total geomagnetic field...  相似文献   
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