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71.
72.
Seed management has until recently been neglected in agrobiodiversity research. Gender dimensions in seed selection, processing, storage and exchange embody critical task areas in the human management of diverse crop species and varieties. This paper focuses on women's roles in seed management in field and homegarden crops in Bangladesh and reports on the findings of a study in two villages in Tangail District. Seventy-five women were surveyed with a questionnaire and subsets interviewed in-depth; focus groups conducted for women and men provided a means of cross-checking responses. Three distinct areas of agrobiodiversity were addressed: the gendered divisions of labour among agricultural tasks; the pervasiveness of seed saving among respondents; and seed management practices and techniques. The results indicate that while men have greater authority over field activities, homegarden production is the exclusive domain of women. Seed management is seen as an extension of women's domestic duties: women are responsible for all seed processing, storage and exchange for field as well as homegarden crops. The vast majority of seeds sown are saved on-farm by women, revealing important cultural, economic and environmental implications for agrobiodiversity conservation and local differences.  相似文献   
73.
ABSTRACT

Modelling changes in biodiversity have become a necessary component of smart urban planning practices. However, concepts such as biodiversity are often evaluated using area-based composite indices, the results of which are heavily reliant on specific parameters chosen. This paper explores the design and implementation of a butterfly biodiversity index by comparing two widely accepted modelling techniques: principal component analysis and spatial multi-criteria decision analysis (MCDA). A high degree of scale dependency has been demonstrated in previous studies exploring the use of area-based composite measures. To evaluate the impact of scale, each model was assessed at two different spatial resolutions. The outcomes were analyzed, mapped and compared using ordinary least squares, geographically weighted regression and global Moran’s I to evaluate relative biodiversity patterns across the City of Toronto, Canada. Findings indicate that the impact of spatial scale was significant, whereby the coarser resolution models were found to be more highly correlated with biodiversity, compared to the finer resolution models. The results of this study contribute to a growing body of literature that explores key conceptual questions regarding the robustness of GIS-based MCDA, the impact of scale in urban ecology studies, and the use of composite indices to manage spatial ecological data.  相似文献   
74.
Lagged ensembles from the operational Climate Forecast System version 2 (CFSv2) seasonal hindcast dataset are used to assess skill in forecasting interannual variability of the December–February Arctic Oscillation (AO). We find that a small but statistically significant portion of the interannual variance (>20 %) of the wintertime AO can be predicted at leads up to 2 months using lagged ensemble averages. As far as we are aware, this is the first study to demonstrate that an operational model has discernible skill in predicting AO variability on seasonal timescales. We find that the CFS forecast skill is slightly higher when a weighted ensemble is used that rewards forecast runs with the most accurate representations of October Eurasian snow cover extent (SCE), hinting that a stratospheric pathway linking October Eurasian SCE with the AO may be responsible for the model skill. However, further analysis reveals that the CFS is unable to capture many important aspects of this stratospheric mechanism. Model deficiencies identified include: (1) the CFS significantly underestimates the observed variance in October Eurasian SCE, (2) the CFS fails to translate surface pressure anomalies associated with SCE anomalies into vertically propagating waves, and (3) stratospheric AO patterns in the CFS fail to propagate downward through the tropopause to the surface. Thus, alternate boundary forcings are likely contributing to model skill. Improving model deficiencies identified in this study may lead to even more skillful predictions of wintertime AO variability in future versions of the CFS.  相似文献   
75.
76.
Williams  James H.  Wilson  Thomas M.  Horspool  Nick  Lane  Emily M.  Hughes  Matthew W.  Davies  Tim  Le  Lina  Scheele  Finn 《Natural Hazards》2019,96(3):1167-1211
Natural Hazards - Tsunamis can have severe impacts on society. In addition to casualties and damage to buildings, they can also damage and disrupt critical infrastructure. To support effective risk...  相似文献   
77.
We evaluate the relationship between the intensity of remanent magnetization and fO2 in natural and synthetic Mars meteorites. The olivine‐phyric shergottite meteorite Yamato 980459 (Y‐980459) and a sulfur‐free synthetic analog (Y‐98*) of identical major element composition were analyzed to explore the rock magnetic and remanence properties of a basalt crystallized from a primitive melt, and to explore the role of magmatic and alteration environment fO2 on Mars crustal anomalies. The reducing conditions under which Y‐980459 is estimated to have formed (QFM‐2.5; Shearer et al. 2006) were replicated during the synthesis of Y‐98*. Y‐980459 contains pyrrhotite and chromite. Chromite is the only magnetic phase in Y‐98*. The remanence‐carrying capacity of Y‐980459 is comparable to other shergottites that formed in the fO2 range of QFM‐3 to QFM‐1. The remanence‐carrying capacity of these low fO2 basalts is 1–2 orders of magnitude too weak to account for the intense crustal anomalies observed in Mars's southern cratered highlands. Moderately oxidizing conditions of >QFM‐1, which are more commonly observed in nakhlites and Noachian breccias, are key to generating either a primary igneous assemblage or secondary alteration assemblage capable of acquiring an intense remanent magnetization, regardless of the basalt character or thermal history. This suggests that if igneous rocks are responsible for the intensely magnetized crust, these oxidizing conditions must have existed in the magmatic plumbing systems of early Mars or must have existed in the crust during secondary processes that led to acquisition of a chemical remanent magnetization.  相似文献   
78.
Petroleum hydrocarbons persist in salt marsh sediments in Winsor Cove (Buzzards Bay, Massachusetts) impacted from the 1974 spill of No. 2 fuel oil by the barge Bouchard 65. Intertidal sediment cores were collected from 2001 to 2005 and analyzed for total petroleum hydrocarbons (TPHs). TPHs content was greatest (as high as 8.7 mg g(-1) dry weight) in the surface sediments and decreased with distance landward. Select samples were analyzed for polycyclic aromatic hydrocarbons (PAHs) with values as high as 16.7 microg g(-1) for total naphthalenes and phenanthrenes/anthracenes. These remaining PAHs are mainly C(4)-naphthalenes and C(1)-, C(2)-, and C(3)-phenanthrenes/anthracenes revealing preferential loss of almost all of the naphthalenes and the parent compound phenanthrene. Inspection of the data indicates that biodegradation, water-washing and evaporation were major removal processes for many of the petroleum hydrocarbons in the marsh sediments. In addition, historical data and photographs combined with their recent counterparts indicate that erosion has physically removed these contaminants from this site.  相似文献   
79.
The distribution, general habits, morphological variation, food, associates and predators ‘Of the common endemic New Zealand echiooid Evechinus chloroticus (Val.) are considered.

Evechinus chloroticus is chiefly a rocky bottom dweller but adults, juveniles and very small individuals often occupy different microhabitats. The urchin is typically found in shallow subtidal situations (<12m) although considerable intertidal populations occur in some areas, particularly towards the north. A superimposed dispersion pattern of population and intra‐population clumping is typical and densities often exceed 50 adults/m2.

Spine length, thickness and sharpness and test thickness vary between populations but no significant variation in test shape (height/diameter) was observed. Variations in spination are probably related to wave exposure while test thickness is at least in part related to nutrition.

In the localities where macroscopic algae are diverse and abundant, Evechinus is almost exclusively algivorous, but it predominantly browses material from the substrate where algae are sparse.

The rhabdocoele, Syndesmis sp. (in the gut) and various tiliates (in the gut and gonad) were commonly found in Evechinus. The urchin provides shelter and food for the clingfish Dellichthys morelandi, and the isopod Exosphaeroma sp. is probably also a close associate.

Known predators include the cymaitiid gastropods Charonia capax and C. rubicunda, the seastar Coscinasterias calamaria, and the blue cod Parapercichthys colias and snapper Chrysophrys auratus.  相似文献   
80.
Wildfires are increasing in severity and frequency in the American West, but there is limited understanding of their economic effects at the community level. We conducted a case study of the impacts of large wildfires in 2008 in Trinity County, California, by examining labor market, suppression spending, and qualitative interview data. We found that the 2008 fires had interrelated effects on several economic sectors in the county. Labor market data indicated a decrease in total private-sector employment and wages and an increase in public-sector employment and wages during the summer of 2008 compared to the previous year, while interviews captured more nuanced impacts for individual businesses.  相似文献   
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