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Cino Pertoldi Lasse Fast Jensen Aage Kristian Olsen Alstrup Ole Lajord Munk Trine Bæk Pedersen Christian Sonne Rune Dietz Tobias Daugaard-Petersen Hanne Ellen Kortegaard Morten Tange Olsen Karin Charlotte Hårding Trine Hammer Jensen 《Acta theriologica》2018,63(1):55-63
Harbor seals (Phoca vitulina) inhabit the seas surrounding Denmark and are an important top predator in the marine food chain. This trophic position exposes them to environmental contaminants with disease epidemics and hunting being additional threats to this population. It is therefore important to study how environmental pollution at the current order of magnitude affects the health of the population. Earlier studies have shown that occurrence of periodontitis could be linked to the amount of pollution the seals were subjected to. In order to investigate this further, 380 skulls and 141 mandibles of harbor seals (Phoca vitulina) from the Wadden Sea, the Limfjord, and Kattegat collected during the period 1970–2014 were examined. The skulls were examined for pathological lesions. The Hounsfield Units (HU) which are correlated to the bone mineral density (BMD) were measured in a subsample (n = 34) using CT scans. The macroscopic examination revealed (with the exception of the Swedish part of Kattegat) a significant increase of pathological lesions over the study period of 1981–2014. The examination of HU showed that median HU measured at multiple sites was highest in the healthy skulls compared to the skulls with one or more of the lesions. A discriminant analysis allowed high discriminatory capacity to separate healthy skulls from the skulls with pathologies, simply by the utilization of the HU data. Former studies of BMD in marine mammals have shown that exposure to environmental chemicals alter BMD and cause periodontitis. The present study, based on temporal and spatial trends in BMD, confirms the results of previous studies. 相似文献
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Root deformation in plantations of container-grown Scots pine trees: effects on root growth,tree stability and stem straightness 总被引:4,自引:0,他引:4
Root system deformation was studied in 23 Scots pine (Pinus sylvestris L.) stands in central Sweden. The study comprised both
plantations created with container-grown plants (Paperpot) and natural stands including young (7–9 year old) and older (19–24
year old) trees. Trees were measured with regards to distribution of roots, root deformation, stability, stem straightness
and wood properties in stumps. Root distribution was most uniform for naturally regenerated trees. Older trees generally showed
a better root distribution than young trees. The young planted trees displayed a high frequency of severely spiralled root
systems, while only a few of the older trees had spiralled root systems. No severe root deformations were observed on naturally
regenerated trees. Naturally regenerated trees were more stable than those which had been planted. Differences in bending
moment, when trees were pulled to an angle of 10°, were considerable between young planted and naturally regenerated trees,
but less pronounced for the older trees. Young planted trees had the highest frequency of severely crooked stem bases, while
naturally regenerated trees had the straightest mode of growth. Tensile strength in peripheral wood samples of the stumps
was substantially lower for planted than for naturally regenerated trees. Strain values to breakage of wood samples, taken
from the root collar and the central- and peripheral part of the stump were lower for planted trees. The conclusions from
this study are that root distribution, tree stability and stem straightness of planted Paperpot-grown trees will improve after
a certain time and approach the state of naturally regenerated trees. As trees grow older, early established crooked stem
bases will be compensated by radial growth and the tree will appear straighter. Inside the stem, however, problems may still
remain with abnormal fibre direction and compression wood together with inferior root strength due to fibre disturbances as
a result of spiralled roots.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
127.
Jenny Foss Abrahamsen Robert B. Sothern Sverre Sandberg Asbj rn Aakvaag Ole Didrik Laerum Rune Smaaland 《Biological Rhythm Research》1999,30(1):29-53
Fifteen bone marrow (BM) and venous blood circadian profiles were obtained from 13 diurnally-active, healthy men sampled every 4-5 h for 24 h. Peripheral blood (PB) was also sampled in subsets of 5 men either for 24 h immediately preceding the BM procedure or 5-6 months afterwards. Cortisol and white and red cell parameters were determined in PB. BM cell cycle distribution was investigated in parallel by flow cytometry for S-phase DNA of total mononuclear cells and subpopulations of erythroid and myeloid precursor cells. On a group basis, significant circadian rhythms were found in PB variables commonly referred to as "marker" rhythms (cortisol, total white cells [WBC], neutrophils [N], lymphocytes [L]), with acrophases less than 2 h apart between the contro l day prior to and during BM sampling. Thus, major, but relatively short-lasting physiological stress, like BM aspirations or blood sampling itself, although repeated several times over 24 h, seemed to have minor influence on these rhythms on days of the BM procedure. When comparing the times of highest or lowest values in PB with times of highest or lowest values in BM, several temporal relationships were found. Among other associations, timing of lowest values in WBC, N and L or highest values in cortisol was significantly predictive of highest values in myeloid cells occurring in the following 12 h, whereas highest values in erythroid cells occurred significantly more often in the 12 h interval beginning 4 h after the time of lowest values in WBC, L and N. The stability in the circadian rhythms of the PB variables suggests that information obtained on one day can be used to guide procedures on the next, such as BM myelotoxic chronotherapy or BM harvesting. 相似文献
128.
Questions: Does natural revegetation from indigenous soil improve the restoration success of roadside areas? What are the effects of topsoil, subsoil and fertilization on natural revegetation? Location: Akershus county, SE Norway (10°25′ E, 59° 44′ N). Methods: We used a recently constructed road through a boreal coniferous forest for a three year (2000–2002), fully replicated revegetation experiment (six replications). Treatments were soil type (two levels; one topsoil and one subsoil type) and fertilization (two levels; NPK and unfertilized control). Ordination methods, constrained ordination methods as well as univariate statistical methods, such as Wilcoxon's signed‐rank test and correlation analysis, were used to assess the relative importance and significance of treatments on the plant species composition. Results: There was no fertilization effect on species composition. The species composition on both soil types was stabilised by the second year. The species dominating the topsoil were more in accordance with the indigenous vegetation than was the case on the subsoil. The significant difference in species composition among blocks, persisting for the entire study period, indicated that local factors are important determinants of the outcome of revegetation. Conclusions: Unfertilized topsoil provides a revegetation result in better accordance with the indigenous vegetation than does subsoil. 相似文献
129.
Thea Ø. Bechshøft Christian Sonne Frank F. Rigét Øystein Wiig Rune Dietz 《Polar Biology》2008,31(8):945-958
Size, growth and sexual dimorphism of nine skull traits was studied in 300 East Greenland and 391 Svalbard polar bears (Ursus maritimus). Two traits were significantly larger in bears from East Greenland compared to Svalbard bears, and trait size was smaller
after 1960 in five traits. For both localities and both age groups (subadult, adult), mean trait size values were higher in
males than females (all: P < 0.05). Gompertz growth models showed trait size increasing with age in seven traits. Depending on the trait, males reached
95% asymptotic trait size at age 3–10, females at age 2–6. The females of both localities matured at approximately the same
age, whereas the Svalbard males generally matured years later than their East Greenland peers. The differences found in the
present study between the two polar bear subpopulations support the notion that East Greenland and Svalbard polar bears probably
should be managed as separate units. 相似文献
130.
Rune Dietz Mads Peter Heide-Jørgensen Pierre Richard Jack Orr Kristin Laidre Hans Christian Schmidt 《Polar Biology》2008,31(11):1295-1306
Twenty-one narwhals tagged in 2003 and 2004 in Admiralty Inlet showed a different summer distributional pattern than previous
narwhal-tracking studies from Somerset Island, Eclipse Sound and Melville Bay. The migration of the narwhals tracked from
Admiralty Inlet moved out through Lancaster Sound 15 days earlier (P < 0.0001) than the narwhals summering around Eclipse Sound, whereas the Admiralty Inlet narwhals reached the mouths of Eclipse
Sound 18 days later (P < 0.0001) than the Eclipse Sound summering population. The winter range of the Admiralty Inlet narwhals overlapped with the
winter range of narwhals from Melville Bay and Eclipse Sound in central southern Baffin Bay and Northern Davis Strait, but
not with the winter range of narwhals from Somerset Island that wintered further north. Distribution size of range, and population
size did not appear to be related. An example of considerable year to year variation between area of summer and winter distribution
in the 2 years was believed to be related to the sample size and number of pods of whales tagged, rather than to differences
in sex or age classes. 相似文献