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991.
Cross-spectral analysis was used to characterize the relationship between climate variability, represented by atmospheric patterns, and annual fluctuations of Fusarium head blight (FHB) disease intensity in wheat. Time series investigated were the Oceanic Ni?o Index (ONI), which is a measure of the El Ni?o-Southern Oscillation (ENSO), the Pacific-North American (PNA) pattern and the North Atlantic Oscillation (NAO), which are known to have strong influences on the Northern Hemisphere climate, and FHB disease intensity observations in Ohio from 1965 to 2010 and in Indiana from 1973 to 2008. For each climate variable, mean climate index values for the boreal winter (December to February) and spring (March to May) were utilized. The spectral density of each time series and the (squared) coherency of each pair of FHB-climate-index series were estimated. Significance for coherency was determined by a nonparametric permutation procedure. Results showed that winter and spring ONI were significantly coherent with FHB in Ohio, with a period of about 5.1 years (as well as for some adjacent periods). The estimated phase-shift distribution indicated that there was a generally negative relation between the two series, with high values of FHB (an indication of a major epidemic) estimated to occur about 1 year following low values of ONI (indication of a La Ni?a); equivalently, low values of FHB were estimated to occur about 1 year after high values of ONI (El Ni?o). There was also limited evidence that winter ONI had significant coherency with FHB in Indiana. At periods between 2 and 7 years, the PNA and NAO indices were coherent with FHB in both Ohio and Indiana, although results for phase shift and period depended on the specific location, climate index, and time span used in calculating the climate index. Differences in results for Ohio and Indiana were expected because the FHB disease series for the two states were not similar. Results suggest that global climate indices and models could be used to identify potential years with high (or low) risk for FHB development, although the most accurate risk predictions will need to be customized for a region and will also require use of local weather data during key time periods for sporulation and infection by the fungal pathogen. 相似文献
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995.
Lee SH Lillehoj HS Jang SI Lee KW Kim DK Lillehoj EP Yancey RJ Dominowski PJ 《Avian diseases》2012,56(2):402-405
The effects against avian coccidiosis of two novel adjuvants, Quil A/cholesterol/dimethyl dioctadecyl ammonium bromide/Carbopol (QCDC) and QCDC/Bay R1005 (R)/cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (CpG ODN [T]) (QCDCRT) emulsified with profilin, a conserved Eimeria recombinant protein, were determined in broiler chickens. Chickens were subcutaneously immunized with isotonic saline (control group), profilin (P), profilin emulsified with QCDC (P-Q), or profilin with QCDCRT (P-QR) at 2 and 9 days post-hatch and orally challenged with 1.0 x 10(4) sporulated oocysts of Eimeria acervulina (EA) at 7 days postimmunization. All profilin-immunized groups showed increased body weight gain when compared to the control group, and the P-QR group had significantly higher body weight gain than did those of the P and P-Q groups following EA challenge infection. All groups immunized with profilin showed significantly decreased intestinal lesions compared with the control group, with the P-QR group showing the lowest intestinal lesions among the profilin-treated groups. Finally, the P-QR group showed greater CD4+/CD8+ and TCR1+/TCR2+ splenocytes and higher antiprofilin serum antibody titers compared with the P and P-Q (or both) groups following EA challenge infection. These results further suggest that vaccination of chickens with profilin, in combination with the QCDCRT adjuvant, may provide a novel control strategy against EA infection in commercial flocks. 相似文献
996.
Illex argentinus, the Argentine short-finned squid, is an important species within the Patagonian shelf ecosystem, where it supports a major multi-national fishery. The fishing fleet operating in this region is comprised of jigging vessels which attract squid using powerful incandescent lights. These fishing lights are detectable in remotely sensed satellite imagery which makes the fishery unusually amenable to a large-scale analysis of its spatial dynamics. In this paper, long-term inter-annual variability in fleet distribution and extent is examined using imagery from the Defence Meteorological Satellite Program-Operational Linescan System (DMSP-OLS) for the period 1993–2005. The fishery was found to occupy a wide area across the shelf and slope, with regions of consistent fishing activity observed on the high seas (45–47°S) and to the north of the Falkland Islands (Malvinas). Distribution of the fishery over the 13-year study period was variable, with 28% of the fished area occupied in 1–2 years, and 7% of the area occupied in 12–13 years. Annual catch levels were positively associated with the extent of the area occupied by the fleet. Higher catches corresponded to the fishery occupying a wide latitudinal range, whereas lower catches were observed during 2004 and 2005 corresponding to a contraction of the fishery away from the south of its range. In years of very high catches, fishing took place along almost the entire latitudinal range of the species. Due to the intensity of fishing, changes in the distribution of the fleet can reflect shifts in the distribution of I. argentinus; this has potential for the long-term monitoring of this highly variable squid fishery. 相似文献
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998.
Gordon Duff David Garnett Peter Jacklyn Jill Landsberg John Ludwig Joe Morrison Paul Novelly Dan Walker Peter Whitehead 《Landscape Ecology》2009,24(8):1135-1143
Approaches to manage for the sustainable use of natural and cultural resources in a landscape can have many different designs.
One design is adaptive collaborative landscape management (ACLM) where research providers and users work closely together
on projects to develop resources while adaptively managing to sustain or maintain landscapes in the long term. We propose
that collaborative projects are more useful for achieving outcomes than integrative projects where participants merely join
their separate contributions. To foster collaborative research projects to adaptively manage landscapes in northern Australia,
a Tropical Savannas Cooperative Research Centre (TSCRC) was established in 1995. The TSCRC is a joint venture of major organizations
involved in research and land management. This paper is our perspective on the four most important ‘lessons learned’ after
using a ACLM-type approach for over 10 y. We learnt that collaboration (working in combination) not necessarily integration
(combining parts into a whole) achieved sustainable outcomes. We found that integration across culturally diverse perspectives
seldom achieved sustainable solutions because it devalued the position of the less empowered participants. In addition, positive
outcomes were achieved when participants developed trust and respect for each other by embracing and respecting their differences
and by sharing unifying concepts such as savanna health. Another lesson learned was that a collaborative organization must
act as an honest broker by resisting advocacy of one view point over another. Finally, we recognized the importance of strongly
investing in communication and networking so that people could adaptively learn from one another’s experiences, understand
each other’s challenges and respect each other’s choices. Our experience confirms the usefulness of the ACLM approach and
highlights its role in the process of sustaining healthy landscapes. 相似文献
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1000.
Tree care in Wallonia (Belgium) depends on the institution in charge (regional or local). Most municipalities have no statutory guidelines for the maintenance of their tree stock. In this situation, it is not surprising that trees are still topped. Moreover, tree owners think that topping is a fast and cheap way to prune trees. We studied crown restoration of 281 roadside Tilia x europaea L. individuals that were topped during the winter of 1992–1993. Our goal was the economic evaluation of three pruning scenarios. Time needed to prune and related tree parameters (such as tree growth) were measured to calculate pruning costs and trees value evolution between 1992 and 2022. Scenario 1 included topping and the necessary crown restoration. Because of differences in topping intensity between the individuals, we were able to categorise the trees into four groups with particular restoration planning. Scenario 2 considered regular topping and scenario 3 regular thinning. We confirmed that topping is not cheaper than regular crown thinning. In the medium term (30 years), topping is 1.4 fold more costly than selective thinning. Also, mean tree value was reduced by about 10 after regular topping. 相似文献