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991.
A set of stable simple common bird names helps non-ornithologist birders, who contribute to conservation by visiting protected areas and participating in citizen science projects. Changes in English bird names have caused discomfort in the local birding community, especially those that followed international standardisation of common bird names between 2000 and 2005. To understand the extent and nature of English bird name changes, an analysis was done of all southern African bird names through the eight editions of Roberts Birds of South/Southern Africa field guides published from 1940 to 2016. Of 813 species listed in both the first and the latest of the field guides, 453 (55.7%) had their names changed, among which 108 (13.3%) had changes in both the group name and the species epithet. The greatest single wave of changes (31.4%) occurred in the first ‘Roberts bird guide’ (the seventh field guide) in 2007, following international standardisation. Mean word and syllable counts of bird names also increased significantly in that edition. Name changes were associated with new authorships, taxonomic changes and use of geographic species epithets. There was a trend towards name stability for southern African endemic species. Further name changes should be kept to a minimum, shortening and simplifying wherever possible. 相似文献
992.
Changes in habitat suitability influence non‐breeding distribution of waterbirds in central Europe
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Waterbird species have different requirements with respect to their non‐breeding areas, aiming to survive and gain condition during the non‐breeding period. Selection of non‐breeding areas could change over time and space driven by climate change and species habitat requirements. To help explain the mechanism shaping non‐breeding area selection, we provide site‐specific analyses of distributional changes in wintering waterbirds in central Europe, located at the centre of their flyways. We use wintering waterbirds as a highly dynamic model group monitored over a long‐time scale of 50 years (1966–2015). We identified species habitat requirements and changes in habitat use at the level of 733 individual non‐breeding (specifically wintering) sites for 12 waterbird species using citizen‐science monitoring data. We calculated site‐specific mean numbers and estimated site‐specific trends in numbers. The site‐specific approach revealed a general effect of mean winter temperature of site (seven of 12 species), wetland type (all species) and land cover (all species) on site‐specific numbers. We found increasing site‐specific trends in numbers in the northern and/or eastern part of the study area (Mute Swan Cygnus olor, Eurasian Teal Anas crecca, Common Pochard Aythya ferina, Great Cormorant Phalacrocorax carbo and Eurasian Coot Fulica atra). Common Merganser Mergus merganser, Great Cormorant, Grey Heron Ardea cinerea, Common Pochard, Eurasian Coot and Common Moorhen Galinulla chloropus increased their site‐specific numbers on standing industrial waters with traditionally low fish stock. The site‐specific dynamics of bird numbers helped us to identify general preference for sites reducing winter harshness (warmer areas, running waters and more wetlands in the site vicinity), as well as indicating climate‐driven changes in spatial use of wintering sites (northern/north‐eastern range changes and changes in preference for industrial waters). This fine‐scale (site‐specific) approach can reveal large‐scale range and distribution shifts driven by climate and environmental changes regardless of the availability of large‐scale datasets. 相似文献
993.
Schrauzer Gerhard N. Shrestha Krishna P. Molenaar Tammy B. Mead Sherri 《Biological trace element research》1986,10(2):79-89
Essentiality of selenium (Se) for Japanese quail,Coturnix coturnix japonica, was confirmed using a formulated semipurified low-Se diet (basal) (0.05 ppm). Selenium-deficiency symptoms appeared in quails
on this diet within 15 d, which corresponded to low levels of hemolysate glutathione peroxidase (GSH-Px) activity. Selenium
administration at 0.05 and 2.0 ppm levels resulted in an increase of hemolysate GSH-Px activity by 64 and 116%, respectively,
in both short- and long-term experiments. Growth over a 2-mo period increased the hemolysate GSH-Px activity by 120% at each
level of dietary Se. A differential response was exhibited by hepatic mitochondrial and soluble GSH-Px activity to Se supplementation,
the former increasing progressively with increments of Se at 0.05, 2.0, and 4.0 ppm by 45, 70 and 150%, respectively. The
soluble GSH-Px activities of tissues, such as liver, kidney, and testis, and RBC membrane-bound activity remained unchanged
in long-term studies at different levels of Se. Replenishment of Se to quails maintained on low-Se diets reflected no change
in RBC membrane-bound and liver-soluble GSH-Px activities, although the activity in hemolysate increased consistently with
Se. The GSH-Px activity in hemolysate was restored to the levels comparable to those of long-term studies only at Se administration
at the 2.0-ppm level. The differential response of mitochondrial and soluble GSH-Px activities to Se and other related observations
on mitochondrial functions suggest an additional role for Se in mitochondrial membrane processes and glutathione-related metabolic
regulations. 相似文献
994.
Trace elements participate in the organ specific impact of 1,2-dichloroethane (EDC) and Disulfiram (tetraethylthiuram disulfide;
Antabuse (DSF)) administered singly or together, on male Sprague-Dawley rats exposed by diet (AIN-76) to DSF (0 and 0.15%
for 10 d before and during exposure to EDC) and by inhalation to EDC (0,153, 304, 455 ppm (v/v); 7 h/d for 5 d/wk for 30 exposure
days). Kidney, liver, spleen, and testes at exposure d 30 as well as progressive urine samples were examined for elemental
content by simultaneous inductively coupled plasma atomic emission spectroscopy. Each compound singly or together produced
EDC dose related (r≥0.8) changes in metal content in organs relative to controls. There were increases induced by EDC alone for P and Sr in the
liver and decreases for Fe, Mg, and P in the spleen. EDC in DSF-exposed animals caused increases in Ca, Cu, Fe, Mn, and S
and a decrease in K in the liver; increases in Ca, Cu, Fe, Mn, Mo, P, and S and a decrease of Zn in the testes; an increase
in Fe and a decrease in K in the spleen; and an increase of P in the kidney. DSF alone increased Cu in the liver but decreased
it in the testes and kidney; Pb was increased in the liver and kidney and Zn in the liver, spleen, and kidney; Al and Si were
increased also in the liver, S in the spleen, and K in the kidney; Mn and Na were decreased in the kidney.
The organs showing histopathology (the liver and testes) both showed increases in Ca, Cu, Fe, Mn, and S. Metals in urine characterized
a “shock” impact of the initial exposure by initial excretion of Na and retention of most other elements. After steady state
(>12 d), EDC alone caused increases for Sr and Zn; for EDC-DSF, EDC also decreased Na in addition to the changes elicited
by DSF alone (increases in S and Zn and a decrease for Cu). The results were interpreted from the perspective of the effects
of metals on the glutathione detoxicative pathway, the concentration of free diethyldithiocarbamate in urine, and an interaction
with bone. Mechanisms of action of EDC, DSF, and EDC-DSF must include consideration of trace elements in addition to organic
intermediates, metabolites, and enzymes. 相似文献
995.
Learning from the past: Diatoms as palaeoecological indicators of changes in marine environments 总被引:2,自引:0,他引:2
The North Sea is seriously threatened by a variety of pollution sources. Terrestrially derived effluents are causing extensive
environmental damage and changes to ecosystems of both the offshore and coastal waters. Coastal and estuarine communities
are being lost to reclamation projects, and there is the future threat of rising sea level associaed with global warming.
The spatial and temporal extent of recent anthropogenic changes are largely unknown due to the paucity of background information.
The possible role of palaeoecological methodology in providing ‘reference levels’ against which current status can be compared,
and their importance for restoration and policy decisions, are presented. The usefulness of diatoms as environmental indicators
is illustrated. The extent of natural and anthropogenic changes on coastal habitats are demonstrated by reference to the Holocene
evolution of the coastline of The Netherlands. Possible profitable areas for further research are outlined,e.g. a diatom nutrient calibration data set for shallow marine embayments. 相似文献
996.
Rats were irradiated with one tibia shielded (95% marrow exposure), total body exposed (TBI, 100%), and only one tibia exposed
(5%), or they were sham irradiated (SI, 0%). Plasma Fe-59 clearance time (T
1/2) and Fe-59 content ratio in the right and left tibia (RT/LT) were assayed to determine the erythroid activity of the overall
marrow of the animals and the relative marrow activity in the exposed and shielded tibias, respectively. When a major fraction
of the overall marrow was shielded or irradiated, the overall erythroid activity levels were identical to those of the SI
and TBI animals, respectively. Interestingly, enhanced normoblastosis was observed in the marrow of the exposed tibia of individual
animals exhibiting normal erythroid activity in 95% of the marrow. Conversely, localized marrow with normal erythroid activity
was found in a shielded tibia of individual rats, demonstrating an enhanced erythroid activity in a major fraction of the
total body. It was concluded that 88 mrad can alter marrow functions in a small isolated skeletal region as effectively as
in the whole body, and tandem assays of the Fe-59T
1/2 and Fe-59 RT/LT can facilitate ultra-low-dose X-ray studies involved with partial body exposures. 相似文献
997.
A. Rascio M. C. Cedola G. Sorrentino D. Pastore G. Wittmer 《Physiologia plantarum》1988,73(1):122-127
The water relations of two durum wheat cultivars ( Triticum durum Desf.) were studied throughout the growing season. Irrigated and unirrigated plants were compared from booting to milk stage; a period where water stress occurred naturally in the field. Modulus of elasticity (ε), turgid weight/dry weight ratio (TW/DW), relative water content at zero turgor (RWCo ) and osmotic potential at full turgor (ε) declined throughout the season while average turgor (ψp ) increased. Water stress induced a further decrease in ψπ 100 and the TW/DW ratio. The elastic modulus varied greatly. During the first stages of growth, cv. Appulo (the more resistant cultivar) showed lower ε values than cv. Valforte. At the milk stage, ε was lower for the unirrigated than the irrigated plants. Correlation coefficients between the TW/DW ratio and the osmotic potential were significant for both cultivars. In cv. Valforte, TW/DW was also correlated with the average turgor and the bulk modulus of elasticity. Structural changes that affect the TW/DW ratio seem to be important factors influencing water relations and drought tolerance in durum wheat. 相似文献
998.
Chromosomal changes in cell lines from mouse tumors induced by nickel sulfide and methylcholanthrene
Nupelwyn T. Christie Donna M. Tummolo Neal W. Biggart E. C. Murphy Jr. 《Cell biology and toxicology》1988,4(4):427-445
Rhabdomyosarcomas were induced in mice by intramuscular injections of crystalline nickel sulfide and 3-methylcholanthrene. At early passage, karyotypes were performed by G-banding for four nickel sulfide cell lines and for three 3-methylcholanthrene cell lines. Six cell lines were near-diploid and one nickel sulfide line was near-tetraploid. Three of the nickel sulfide cell lines were characterized by a rearranged marker chromosome which was present in a majority of the cells of each line. The rearrangements leading to the formation of marker chromosomes were different in each nickel sulfide cell line but involved chromosome 4 in two of the nickel sulfide cell lines. Extra copies of chromosome 15 were present in two nickel sulfide cell lines. Possible rearrangement and/or gene activation was examined for the c-mos oncogene on chromosome 4 and the c-myc oncogene on chromosome 15, but no alteration or activation was observed. None of the 3-methylcholanthrene cell lines contained rearranged marker chromosomes; however, one MCA cell line did contain large numbers of double minutes. In all cell lines, minichromosomes (small atypical acrocentric chromosomes) were observed that contained distinct centromeric regions but no other G-positive bands.Abbreviations DHFR
dihydrofolate reductase
- MCA
3-methylcholanthrene
- NS
nickel sulfide 相似文献
999.
Cellular and molecular aspects of myelin protein gene expression 总被引:27,自引:0,他引:27
1000.
Postmortem and Regional Changes of Serotonin, 5-Hydroxyindoleacetic Acid, and Tryptophan in Brain 总被引:1,自引:1,他引:0
Using a specific and sensitive high pressure liquid chromatographic technique for the measurement of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and tryptophan (TRP), we found that there were no changes in 5-HT or 5-HIAA in the rat cortex when left in situ for 6 h at room temperature or 24 h at 4 degrees C. Only a minimal 14% increase in 5-HT was observed after 24 h at 4 degrees C in the striatum of the same animals. Concentrations of TRP, however, were increased significantly in both brain regions by these postmortem delay procedures. A second study revealed that there were significant regional 5-HT and 5-HIAA concentration differences within the cerebral cortex. The frontal cortex was shown to have the highest concentrations of 5-HT and 5-HIAA. Further, within the frontal cortex, 5-HIAA levels varied, showing apparent progressive rostral to caudal increases. 5-HT concentrations, however, remained constant within the frontal cortex. These results are discussed in reference to the conflicting reports of the previous human suicide and postmortem studies. 相似文献