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991.
The reservoirs studied are located on a very important migratory flyway in the Mexican Central Plateau. The survey included the waterfowl, macrophytes and physico-chemical parameters of three localities visited on ten occasions during a 1-year period. A total of 23 waterfowl species were observed: 6 transients, 10 winter visitants, and 7 residents. A period of increased richness was detected in winter, when migratory species arrive at the reservoirs. A canonical correspondence analysis showed segregation patterns of the species for the use of the space. Migratory ducks occurred in Umécuaro, where there is a larger variety of macrophytes and eutrophication occurs. Loma Caliente was the area with less eutrophication and was not preferred by ducks. Gallinago gallinago and Ardea herodias were the species with the highest frequency of occurrence, while the Effluent was the preferred site of resident species. Although the reservoirs studied are small, they are suitable for a significative number of species to be considered as a waterfowl protection and conservation zone. 相似文献
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994.
ABSTRACTWe introduce what we have coined the multiplier effect. We explain the steep upward mobility of children of low-educated immigrants by studying how they overcome obstacles on their regular pathway, via alternative routes or through loopholes in the education and labour market system. The idea of the multiplier effect is that they virtually propel themselves forward in their careers. Essential is that each successful step forward offers new possibilities on which they build, thereby accumulating cultural and social capital and multiplying their chances of success. Initial small differences with their less successful co-ethnic peers generate an increasingly wider gap over time. Cultural and social capital theories primarily explain the reproduction of inequalities in society. The multiplier effect explains the breaking of the perpetual cycle of this reproduction, enabling steep upward mobility even when this group does not initially possess the right cultural and social capital to be successful. 相似文献
995.
Ömer Ertürk 《Entomological Research》2017,47(5):286-294
The purpose of this paper is to identify the nest materials, some physical characteristics and the elemental composition of the nest of Dolichovespula saxonica (Fabricius, 1793). The nest surfaces were observed with a stereomicroscope and scanning electron microscope (SEM). In the inner surface of the D. saxonica nest the medium thickness of the fibers in the envelope and comb varied between 7.14 and 26.9 μm, respectively and averaged 16.4 μm. In the outer surface of the nest the medium thickness of the fibers in the envelope and comb were between 3.52 and 5.70 μm, respectively and averaged 4.63 μm. The nitrogen concentration of the nest of D. saxonica was 0.616% and the amount of protein was 3.08%. The percentages of the fibers, saliva, oil and the water absorption capacity were calculated as 67–70%, 23–30%, 12–18% and 110–140%, respectively. However, the amount of the element Cadmium (Cd) in the nest was found to have a value of 0.2 ppm. The major compounds of wasp nests are plant fibers, saliva and oil. However, the concentrations and ratios of the nest material compounds depend on the plant variety, place of origin, and time of harvest as well as on the processing and saliva conditions. The colors of the nest are beige, cream and grey with long dark brown lines. As a result of our study, we have found that the rates and quantities of physical characteristics, elemental composition and the fibers in the envelope and comb of the nest of D. saxonica change with environmental conditions. 相似文献
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997.
Zahide Özdemir 《Archives Of Phytopathology And Plant Protection》2017,50(13-14):674-686
Sesame phyllody causes significant yield losses mainly in Mediterranean region of Turkey. To detect and identify phytoplasmas of sesame and the cicadellid vector Orosius orientalis, samples were collected during 2011–2013 in Antalya. Nested PCR amplification of the 16S rDNA gave an amplification band of approximately 1246 bp corresponding to the 16Sr F2nR2 region. Identification of the phytoplasmas based on sequence homology revealed presence of the 16Sr groups II (Peanut witches’-broom, PnWB), VI (Clover proliferation, CP) and IX (Pigeon pea witches’-broom, PPWB) in sesame plants. PnWB and CP were detected in O. orientalis. Subgroups were determined by sequencing and PCR-RFLP of the F2nR2 region. 16Sr subgroups II-D, VI-A and IX-C were identified from sesame and II-D and VI-A subgroups from the insect vector. This study shows that phytoplasmas in sesame and O. orientalis are genetically diverse and to the knowledge, VI-A group phytoplasmas from sesame and O. orientalis were characterised molecularly for the first time in Turkey. 相似文献
998.
RACHEL PRZESLAWSKI SHANE AHYONG MARIA BYRNE GERT WÖRHEIDE PAT HUTCHINGS 《Global Change Biology》2008,14(12):2773-2795
Climate change is threatening tropical reefs across the world, with most scientists agreeing that the current changes in climate conditions are occurring at a much faster rate than in the past and are potentially beyond the capacity of reefs to adapt and recover. Current research in tropical ecosystems focuses largely on corals and fishes, although other benthic marine invertebrates provide crucial services to reef systems, with roles in nutrient cycling, water quality regulation, and herbivory. We review available information on the effects of environmental conditions associated with climate change on noncoral tropical benthic invertebrates, including inferences from modern and fossil records. Increasing sea surface temperatures may decrease survivorship and increase the developmental rate, as well as alter the timing of gonad development, spawning, and food availability. The broad latitudinal distribution and associated temperature ranges of several pantropical taxa suggest that some reef communities may have an in‐built adaptive capacity. Tropical benthic invertebrates will also show species‐specific sublethal and lethal responses to sea‐level rise, ocean acidification, physical disturbance, runoff, turbidity, sedimentation, and changes in ocean circulation. In order to accurately predict a species' response to these stressors, we must consider the magnitude and duration of exposure to each stressor, as well as the physiology, mobility, and habitat requirements of the species. Stressors will not act independently, and many organisms will be exposed to multiple stressors concurrently, including anthropogenic stressors. Environmental changes associated with climate change are linked to larger ecological processes, including changes in larval dispersal and recruitment success, shifts in community structure and range extensions, and the establishment and spread of invasive species. Loss of some species will trigger economic losses and negative effects on ecosystem function. Our review is intended to create a framework with which to predict the vulnerability of benthic invertebrates to the stressors associated with climate change, as well as their adaptive capacity. We anticipate that this review will assist scientists, managers, and policy‐makers to better develop and implement regional research and management strategies, based on observed and predicted changes in environmental conditions. 相似文献
999.
This paper presents a list of some medicinal plants distributed in the East Anatolia region. The list was prepared during an ethnobotanical survey of the region from 1995 to 2002. East Anatolia has a rich flora due to its variable climate and its many ecological zones. This diversity in flora provides a rich source of medicinal plants that has been long utilized by Anatolian cultures; and hence, accounts for the remarkable accumulation of medicinal folk knowledge for the region. This paper provides information about 71 useful plants grown in the region, 20 of which are reported for the first time. In addition to the scientific names, vernacular names and medicinal uses are given for each plant. 相似文献
1000.
An ethnobotanical survey was made of the villages of the Ilica District, Erzurum Province, Turkey. The authors interviewed
130 people in 60 villages. The information so obtained was classified according to the use of plants for food, fuel, dye,
and construction materials, as well as for miscellaneous uses. All in all, this study revealed 60 plant taxa that were useful
to the villagers of this district. 相似文献