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581.
582.
Poynter S Phipps JD Naranjo-Pino A Sanchez-Morgado JM 《Veterinary microbiology》2009,134(3-4):272-278
Molecular diagnostic methods using the polymerase chain reaction (PCR) are the gold standard in Helicobacter diagnostics. Most rely on the amplification of parts of the 16S rRNA gene sequence. Therefore, the validity and accuracy of results depends heavily on the PCR design and the time of its publication because new sequences are continually being submitted to databases. Here we report the presence of helicobacter in commercially bred mice supposedly free of this infection. Furthermore, three out of six different commercial laboratories performing helicobacter testing on the same spiked faecal samples failed to detect and identify H. hepaticus. We designed a simple generic PCR assay that amplifies a 261bp amplicon spanning two of the seven variable regions in the 16S rRNA of helicobacter. Using this assay together with an established generic assay designed by Bohr [Bohr, U.R., Primus, A., Zagoura, A., Glasbrenner, B., Wex, T., Malfertheiner, P., 2002. A group-specific PCR assay for the detection of Helicobacteraceae in human gut. Helicobacter 7, 378-383] and then cloning and sequencing their products, we detected the H. hepaticus used in the study that three commercial laboratories failed to detect. We think these assays together could detect all the currently known species of helicobacter and hopefully the new ones as well. In addition, we have been able to identify different species of helicobacter and their relative proportions infecting a single animal. This information has also shown that some helicobacters may have a much broader host range than originally reported. 相似文献
583.
Anne A. Wooldridge DVM Thomas L. Seahorn DVM MS Jamie Williams MS DVM H. Wayne Taylor DVM Ph.D. Julian L. Oliver DVM Ph.D. Dae Young Kim DVM Thomas J. Vicek DVM 《Veterinary radiology & ultrasound》1999,40(4):361-364
A 2-year-old quarter horse gelding presented for evaluation of polyuria and polydipsia. Azotemia was detected on serum chemistry profile. Small, misshapen, hyperechoic kidneys with decreased corticomedullary demarcation, hydronephrosis, and a right nephrolith were noted ultrasonographically. The diagnosis of end-stage kidney disease and dysplasia was made histopathologically using ultrasound-guided biopsy. Two ureteroliths were found in the right ureter via cystoscopy, and a nephrolith was seen in the right kidney at necropsy. Clinical, ultrasonographic, and pathologic features of equine urolithiasis and renal dysplasia are discussed. 相似文献
584.
Hayden T. Schilling Jason D. Everett James A. Smith John Stewart Julian M. Hughes Moninya Roughan Colette Kerry Iain M. Suthers 《Fisheries Oceanography》2020,29(4):309-323
Transport of larvae by ocean currents is an important dispersal mechanism for many species. The timing and location of spawning can have a large influence on settlement location. Shifts in the known spawning habitat of fish, whether due to climate or the discovery of new spawning stock, can influence the distribution of juveniles and our understanding of connectivity. The globally distributed species; Pomatomus saltatrix, is one such example where a previously unrecognised summer spawning event and a more southern latitudinal extent was recently reported for the southwest Pacific population. Although restrictions are in place to protect the traditional spawning event, the importance of the newly recognised summer spawning event is uncertain. Here, we investigate larval dispersal of P. saltatrix using particle tracking simulations to identify the contributions of the different spawning events to settlement. By modelling dispersal of larvae released in northern and mid‐latitude regions over the Austral spring and summer, we show that the newly recognised mid‐latitude summer spawning event contributes over 50% of the larvae reaching southern latitudes. This is due to a reduced (1–2 days) pelagic larval duration (associated with temperature), resulting in reduced larval mortality, and the seasonal (summer) strengthening of the East Australian Current (EAC) transporting particles ~50 km further south. These findings demonstrate that in dynamic boundary current systems such as the EAC, the final settlement location of larvae that are transported by ocean currents can vary considerably depending on the timing and location of spawning and that multiple spawning events are important for maximum dispersal. 相似文献
585.
Jiangang Luo Jerald S. Ault Bruce T. Ungar Steven G. Smith Michael F. Larkin Thomas N. Davidson David R. Bryan Nicholas A. Farmer Scott A. Holt A. Scott Alford Aaron J. Adams Robert Humston Adam S. Marton David Mangum Russell Kleppinger Angel Requejo Julian Robertson 《Fish and Fisheries》2020,21(2):290-318
Understanding large‐scale migratory behaviours, local movement patterns and population connectivity are critical to determining the natural processes and anthropogenic stressors that influence population dynamics and for developing effective conservation plans. Atlantic tarpon occur over a broad geographic range in the Atlantic Ocean where they support valuable subsistence, commercial and recreational fisheries. From 2001 through 2018, we deployed 292 satellite telemetry tags on Atlantic tarpon in coastal waters off three continents to document: (a) seasonal migrations and regional population connectivity; (b) freshwater and estuarine habitat utilization; (c) spawning locations; and (d) shark predation across the south‐eastern United States, Gulf of Mexico and northern Caribbean Sea. These results showed that some mature tarpon make long seasonal migrations over thousands of kilometres crossing state and national jurisdictional borders. Others showed more local movements and habitat use. The tag data also revealed potential spawning locations consistent with those inferred in other studies from observations of early life stage tarpon leptocephalus larvae. Our analyses indicated that shark predation mortality on released tarpon is higher than previously estimated, especially at ocean passes, river mouths and inlets to bays. To date, there has been no formal stock assessment of Atlantic tarpon, and regional fishery management plans do not exist. Our findings will provide critical input to these important efforts and assist the multinational community in the development of a stock‐wide management information system to support informed decision‐making for sustaining Atlantic tarpon fisheries. 相似文献
586.
587.
The green mussel, Perna viridis is known to have the ability to selectively ingest certain suspended particles from water. However, the preferential ingestion of specific phytoplankton taxa by P. viridis under different environmental conditions is not well understood. A study was undertaken to identify the phytoplankton taxa that are preferentially ingested and rejected by P. viridis in different environmental conditions at Marudu Bay, Malaysia. Phytoplankton abundance and composition in stomach and surrounding waters were determined microscopically. The gonad development stages of P. viridis and various environmental parameters of the bay including temperature, salinity, dissolved oxygen, current speed, pH, visibility, chlorophyll a, nutrients concentration and suspended particles were also determined. Results of current study demonstrated that selective ingestion in P. viridis was mainly influenced by seston concentration, phytoplankton abundance and composition. At high seston concentration with low phytoplankton abundance, P. viridis selectively ingested Coscinodiscus spp. In contrast, P. viridis was found to ingest wider range of phytoplankton at low seston concentration and high phytoplankton abundance. Interestingly, Chaetoceros spp. and Bacteriastrum spp. were selectively rejected by P. viridis in both high and low seston conditions. Nevertheless, no selective ingestion behaviour was evidenced in low seston with low phytoplankton conditions. Besides phytoplankton, zooplankton has also contributed significantly in the diet of P. viridis, where high numbers of copepod and bivalve larvae were found in the stomach. The findings of current study can be useful in determining potential farming sites for green mussel in future. 相似文献
588.
589.
【目的】为了探讨生物有机肥长期施用对宁夏引黄灌区盐碱土壤化学和微生物特性的影响,明确生物有机肥的最佳施用量及施肥模式。【方法】以田间连续4年定位试验为依托,研究生物有机肥施用量0 t/hm2(CK)、4.5 t/hm2(T1)、9 t/hm2(T2)、13.5 t/hm2(T3)及生物有机肥9 t/hm2配施无机化肥360 kg/hm2(N)(T4)对玉米根系土壤养分含量、酶活性、微生物生物量和微生物群落多样性及玉米产量的影响。【结果】:(1)连续四年施用生物有机肥可明显降低土壤pH和全盐含量。土壤养分含量及土壤酶活性随着生物有机肥施用量增加呈递增趋势,且生物有机肥施用9 t/hm2时,增施无机化肥可显著增加土壤速效钾含量14.73%;(2)土壤微生物群落代谢AWCD值和土壤微生物种群代谢多样性指均随着生物有机肥施用量的增加而增加,单施生物有机肥13.5 t/hm2处理下土壤培养192 h时AWCD值为0.84,经Tukey检验分析,Shannon(H)和Mcintosh(U)指数较CK分别增加10.11%和62.67%。(3)随着生物有机肥施用量增加,土壤微生物生物量碳氮磷含量呈递增趋势,各处理分别比CK增加66.78%、59.19%和51.84%;(4)施用生物有机肥可明显增加玉米产量,提高玉米产值,其中以生物有机肥施用9 t/hm2配施无机化肥360 kg/hm2(N)时,玉米产量和净收入最佳,分别为11499 kg/hm2和8709元/hm2。【结论】长期施用生物有机肥可改善宁夏盐碱土壤质地,提高土壤质量,增加土壤生物活性及玉米产量,其中以生物有机肥施用9 t/hm2配施无机化肥360 kg/hm2(N)时综合效果最佳。 相似文献
590.