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991.
A.G. Becker J.F. Gonçalves L.O. Garcia E.R. Behr F.J.K. Mallmann D.L. Graça B. Baldisserotto 《Fish physiology and biochemistry》2006,32(2):105-112
The levels of various ions (Na+, Cl−, Ca2+, Mg2+, K+) in the fluid phase of the gastrointestinal contents and of the plasma were determined in four teleosts with different feeding habits: traira (Hoplias malabaricus), hassar (Hoplosternum littorale), silver catfish (Rhamdia quelen), and grass carp (Ctenopharyngodon idella). The results showed that most ionic levels in the fluid phase of the gastrointestinal tract seem to be affected by feeding habit and that these levels can be different from those found in the plasma. In practical terms, these results suggest that ionic levels of the gastrointestinal contents should be considered when preparing solutions for studies of intestinal absorption in fishes. 相似文献
992.
Campbell C Pert A Jennifer Mordue Bríd O'Shea Ian R Bricknell 《Aquaculture Research》2012,43(6):799-805
The reproductive success of Lepeophtheirus salmonis settled on host and non‐host fish has been compared. Triplicate single species tanks of Atlantic salmon, marine three‐spined sticklebacks, saithe and Atlantic cod were exposed to 10 adult female L. salmonis per tank (n=30 lice per species). Adult female L. salmonis settlement and egg string production occurred only on salmon and cod, with no egg production occurring on saithe and three‐spined sticklebacks. The number of eggs in egg strings, hatching success of eggs and the survival of all larval stages to the copepodid stage were severely affected by the species of fish on which female L. salmonis had settled. L. salmonis settled on cod produced significantly fewer eggs, lower hatching rates and lower survival rates of larvae than females on Atlantic salmon. The production of egg strings by L. salmonis females infecting cod, which successfully hatch and moult through to the infective copepodid stage, albeit in small numbers, is discussed in terms of the implications to aquaculture and salmon and cod farming scenarios. 相似文献
993.
Álvaro González Jesús D. Celada Pedro M. Melendre José M. Carral María Sáez‐Royuela Rocío González Vanesa García 《Aquaculture Research》2013,44(3):354-358
Two experiments were conducted on the effects of bronopol in the artificial incubation of crayfish eggs (Pacifastacus leniusculus) with the aim to search an alternative to formaldehyde. In the first experiment, 50, 250, 500 and 1000 ppm bronopol and 3000 ppm formaldehyde (control) in periodical administrations were tested on a density of 6.6 eggs cm?2. After 44 days of incubation, the highest survival was obtained with 1000 ppm bronopol (81.9% to stage 2 juvenile, with no significant difference from formaldehyde), whereas lower bronopol concentrations resulted in significantly lower survival. In the second experiment, 1000, 3000 and 5000 ppm bronopol and 3000 ppm formaldehyde (control) administered for 15 min every second day were tested on eggs at a density of 20 eggs cm?2. After 78 days of incubation, bronopol at 3000 ppm allowed for a stage 2 juvenile survival rate of 65.0% (with no significant difference from formaldehyde), whereas significantly lower survival was obtained with 1000 ppm or 5000 ppm. This study shows that bronopol may constitute an alternative to formaldehyde in the artificial incubation of crayfish eggs. A concentration of 3000 ppm administered for 15 min every second day may be adequate even on long incubations at high densities (at least 20 eggs cm?2, one complete layer). 相似文献
994.
Colín-González AL Ortiz-Plata A Villeda-Hernández J Barrera D Molina-Jijón E Pedraza-Chaverrí J Maldonado PD 《Plant foods for human nutrition (Dordrecht, Netherlands)》2011,66(4):348-354
Different garlic products reduce the cerebral ischemic damage due to their antioxidant properties. In this work, we investigated
the effect of aged garlic extract (AGE) on cyclooxygenase-2 (COX-2) protein levels and activity, and its role as a possible
mechanism of neuroprotection in a cerebral ischemia model. Animals were subjected to 1 h of ischemia plus 24 h of reperfusion.
AGE (1.2 ml/kg weight, i.p.) was administered at onset of reperfusion. To evaluate the damage induced by cerebral ischemia, the neurological deficit,
the infarct area, and the histological alterations were measured. As an oxidative stress marker to deoxyribonucleic acid,
8-hydroxy-2-deoxyguanosine (8-OHdG) levels were determined. Finally, as inflammatory markers, TNFα levels and COX-2 protein
levels and activity were measured. AGE treatment diminished the neurological alterations (61.6%), the infarct area (54.8%)
and the histological damage (37.7%) induced by cerebral ischemia. AGE administration attenuated the increase in 8-OHdG levels
(77.8%), in TNFα levels (76.6%), and in COX-2 protein levels (73.6%) and activity (30.7%) induced after 1 h of ischemia plus
24 h of reperfusion. These data suggest that the neuroprotective effect of AGE is associated not only to its antioxidant properties,
but also with its capacity to diminish the increase in TNFα levels and COX-2 protein expression and activity. AGE may have
the potential to attenuate the cerebral ischemia-induced inflammation. 相似文献
995.
Nutritional status affects the processes of flowering and fruiting of plants. This study was conducted to determine the effects of fertilizer application on flowering, fruiting, and leaf nutrient content of Vanilla planifolia (Jacks. ex Andr). Treatments consisted of the application of grade 10-20-20 nitrogen, phosphorus, and potassium (NPK) fertilizer to the substratum in annual doses of 20, 50, and 100 g/plant plus a monthly application of foliar fertilizer. Two more treatments were foliar fertilization and no fertilization (control). Treatments increased the number of inflorescences and flower buds per plant, as well as the number and weight of fruits per plant, and decreased the abortion of flowers and immature fruits. These effects depended on the type of fertilizer, the amount applied, and the time of evaluation. The best results were obtained with the 100 g/plant/year treatment with an annual production of 1.5 kg of fruits per plant in the second year. Unfertilized plants produced 0.55 kg/plant/year. Differences were also found in foliar content of N, P, K, and copper (Cu) between vegetative and reproductive branches. Application of fertilizer to the substratum appears to improve reproductive parameters of vanilla plants and the production of beans, while foliar fertilization alone was ineffective in increasing crop productivity. Nutrients also seem to translocate from mature leaves to fruit racemes. 相似文献
996.
Samuli Junttila Mikko Vastaranta Jarno Hämäläinen Petri Latva-käyrä Markus Holopainen Rocío Hernández Clemente 《Scandinavian Journal of Forest Research》2017,32(2):154-165
The effect of forest structure and health on the relative surface temperature captured by airborne thermal imagery was investigated in Norway Spruce-dominated stands in Southern Finland. Airborne thermal imagery, airborne scanning light detection and ranging (LiDAR) data and 92 field-measured sample plots were acquired at the area of interest. The surface temperature correlated most negatively with the logarithm of stem volume, Lorey’s height and the logarithm of basal area at a resolution of 254?m2 (9?m radius). LiDAR-derived metrics: the standard deviations of the canopy heights, canopy height (upper percentiles and maximum height) and canopy cover percentage were most strongly negatively correlated with the surface temperature. Although forest structure has an effect on the detected surface temperature, higher temperatures were detected in severely defoliated canopies and the difference was statistically significant. We also found that the surface temperature differences between the segmented canopy and the entire plot were greater in the defoliated plots, indicating that thermal images may also provide some additional information for classifying forests health status. Based on our results, the effects of forest structure on the surface temperature captured by airborne thermal imagery should be taken into account when developing forest health mapping applications using thermal imagery. 相似文献
997.
998.
In the southwest part of the Iberian Peninsula the dominant land-use are the Portuguese montados and Spanish dehesas, parkland
forested areas of anthropogenic origin dominated by cork oak. They form a wooded matrix with open areas, scattered woodlands
and undisturbed patches of Mediterranean forest and scrublands. The montados are characterized by a rich bird community. We
have focus our study in a multidisciplinary approach, evaluating how management and landscape patterns influence the bird
community in order to identify potential threats to its conservation. The study was conducted in the Site of Community Importance
of Serra de Monfurado were 70% of the area is cork and holm oaks. We used data from 120 10-min point counts. Using variation
partitioning, we determined the independent and joint effects of Forest, Management and Habitat variables. The variation captured
in bird assemblage was 65.06%. Most of the explained variation was related to the Habitat and Management variables. The explanatory
variables that were high-lighted as important predictors were variables that reflected tree and shrub density and cork removal.
Modelling for forest species through generalized linear models (GLM) emphasize that the management plays an important role
in the species distribution. The most important variables selected in models reflected cattle grazing and cork removal. Our
results point out that the type of management is crucial to maintain the equilibrium in bird community associated to montados.
Farmland and forest species will benefit from areas with different tree densities, small patches of Mediterranean scrubs in
the understory and correct livestock numbers. 相似文献
999.
Javier Fernández Laura Marín Raquel álvarez-Alonso Saúl Redondo Juan Carvajal Germán Villamizar Claudio J. Villar Felipe Lombó 《Marine drugs》2014,12(5):2668-2699
Diverse actinomycetes produce a family of structurally and biosynthetically related non-ribosomal peptide compounds which belong to the chromodepsipeptide family. These compounds act as bisintercalators into the DNA helix. They give rise to antitumor, antiparasitic, antibacterial and antiviral bioactivities. These compounds show a high degree of conserved modularity (chromophores, number and type of amino acids). This modularity and their high sequence similarities at the genetic level imply a common biosynthetic origin for these pathways. Here, we describe insights about rules governing this modular biosynthesis, taking advantage of the fact that nowadays five of these gene clusters have been made public (thiocoraline, triostin, SW-163 and echinomycin/quinomycin). This modularity has potential application for designing and producing novel genetic engineered derivatives, as well as for developing new chemical synthesis strategies. These would facilitate their clinical development. 相似文献
1000.
McEwen AS Hansen CJ Delamere WA Eliason EM Herkenhoff KE Keszthelyi L Gulick VC Kirk RL Mellon MT Grant JA Thomas N Weitz CM Squyres SW Bridges NT Murchie SL Seelos F Seelos K Okubo CH Milazzo MP Tornabene LL Jaeger WL Byrne S Russell PS Griffes JL Martínez-Alonso S Davatzes A Chuang FC Thomson BJ Fishbaugh KE Dundas CM Kolb KJ Banks ME Wray JJ 《Science (New York, N.Y.)》2007,317(5845):1706-1709
Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per pixel. Boulders ranging up to approximately 2 meters in diameter are ubiquitous in the middle to high latitudes, which include deposits previously interpreted as finegrained ocean sediments or dusty snow. Bright gully deposits identify six locations with very recent activity, but these lie on steep (20 degrees to 35 degrees) slopes where dry mass wasting could occur. Thus, we cannot confirm the reality of ancient oceans or water in active gullies but do see evidence of fluvial modification of geologically recent mid-latitude gullies and equatorial impact craters. 相似文献