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Repeated sublethal freshwater exposures reduce the amoebic gill disease parasite,Neoparamoeba perurans,on Atlantic salmon 下载免费PDF全文
Daniel William Wright Barbara Nowak Frode Oppedal Phil Crosbie Lars Helge Stien Tim Dempster 《Journal of fish diseases》2018,41(9):1403-1410
Freshwater bathing is one of the main treatment options available against amoebic gill disease (AGD) affecting multiple fish hosts in mariculture systems. Prevailing freshwater treatments are designed to be long enough to kill Neoparamoeba perurans, the ectoparasite causing AGD, which may select for freshwater tolerance. Here, we tested whether using shorter, sublethal freshwater treatment durations are a viable alternative to lethal ones for N. perurans (2–4 hr). Under in vitro conditions, gill‐isolated N. perurans attached to plastic substrate in sea water lifted off after ≥2 min in freshwater, but survival was not impacted until 60 min. In an in vivo experiment, AGD‐affected Atlantic salmon Salmo salar subjected daily to 30 min (sublethal to N. perurans) and 120 min (lethal to N. perurans) freshwater treatments for 6 days consistently reduced N. perurans cell numbers on gills (based on qPCR analysis) compared to daily 3 min freshwater or seawater treatments for 6 days. Our results suggest that targeting cell detachment rather than cell death with repeated freshwater treatments of shorter duration than typical baths could be used in AGD management. However, the consequences of modifying the intensity of freshwater treatment regimes on freshwater tolerance evolution in N. perurans populations require careful consideration. 相似文献
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Pierre Girod Océane Lierhmann Teddy Urvois Ted C. J. Turlings Marc Kenis Tim Haye 《Journal of pest science》2018,91(4):1241-1250
The Asian spotted wing drosophila, Drosophila suzukii, has recently become a serious pest of soft fruits in Europe. Classical biological control through the introduction of larval parasitoids from its native range in Asia is presently being considered. However, host specificity of potential biological control agents has to be determined to avoid releasing species that may have unintended non-target impacts. Larvae of six different European non-target fly species and the target D. suzukii were exposed either on diet or blueberries to three Asian larval parasitoids, Asobara japonica, Leptopilina japonica, and Ganaspis cf. brasiliensis, and one European species, Leptopilina heterotoma. Asobara japonica showed the lowest specificity, attacking and developing in all Drosophilidae. Leptopilina japonica successfully parasitized two non-target Drosophilidae, D. melanogaster and D. subobscura, with one singly progeny emerging from D. immigrans. Ganaspis cf. brasiliensis had the highest level of specificity but variations occurred between two geographical populations tested. A Japanese population was strictly specific to D. suzukii, whereas another population from China parasitized D. suzukii, D. melanogaster and sporadically D. subobscura. The European L. heterotoma successfully developed in D. melanogaster, D. subobscura and occasionally in D. immigrans, but nearly all eggs and larvae in D. suzukii were encapsulated. These results show that Ganaspis cf. brasiliensis is the species with the highest potential for biological control, but more studies are needed on its taxonomic status and the existence of biotypes or cryptic species varying in their specificity before field releases can be conducted in Europe. 相似文献
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Ellis T Berrill I Lines J Turnbull JF Knowles TG 《Fish physiology and biochemistry》2012,38(1):189-199
Mortality has received insufficient attention as a fish welfare topic. Here, we aim to prompt fish farming stakeholders to
discuss fish mortalities in relation to welfare. Mortality in farmed fish populations is due to a variety of biotic and abiotic
causes, although it is often difficult to differentiate between underlying and immediate causes of mortality. Most mortality
appears to occur during episodes associated with disease outbreaks and critical periods (in development or production). Most
causes of mortality can be assumed to be associated with suffering prior to death. As mortality rates in farmed fish populations
are suspected to rank amongst the highest in commonly farmed vertebrate species, mortality should be a principal fish welfare
issue. Long-term mortality rates can be used as a retrospective welfare performance indicator and short-term mortality rates
as an operational welfare indicator. Scrutiny of mortality records and determining causes of death will enable action to be
taken to avoid further preventable mortality. The welfare performance of fish farms should only be judged on levels of predictable
and preventable mortality. Fish farmers will already be monitoring mortality due to commercial and legal requirements. As
profitability in fish farming is directly linked to survival, confronting mortality should ultimately benefit both fish and
farmers. 相似文献
36.
Tim G. B. Hart 《Agriculture and Human Values》2011,28(3):321-333
Technologies and services provided to resource-poor farmers need to be relevant and compatible with the context in which they
operate. This paper examines the contribution of extension services to the food security of resource-poor farmers in a rural
village in South Africa. It considers these in terms of the local context and the production of African vegetables in household
food plots. A mixture of participatory, qualitative and quantitative research tools, including a household survey, is used
to argue that local production practices contribute more to food security requirements than the extension services. This is
because of the ability of African vegetables to grow relatively well in semi-arid areas where other exotic plants do not,
their ability to provide at least two foodstuffs during their life cycle, and the ability of either the fruit or the leaves,
or both, to be dried and stored for consumption in the winter months. These crops can make a significant contribution in terms
of household food security, but a number of social and agroecological factors are constraining their production and placing
their availability under threat. Despite this, the extension services remain focused on certain activities within vegetable
garden projects, even when these are not meeting their proposed purpose—food security by means of cash-crop production. The
paper concludes that social and agroecological constraints could be improved if the extension services were changed. This
could include the use of context specific and low-cost technologies to ensure that these crops are able to increase their
contribution to household food security for resource-poor farmers in semi-arid areas. 相似文献
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Véronique Martin‐Bouyer Stijn Schauvliege Luc Duchateau Tim Bosmans Frank Gasthuys Ingeborgh Polis 《Veterinary anaesthesia and analgesia》2010,37(2):87-96
ObjectiveTo investigate the cardiovascular effects of epidural romifidine in isoflurane-anaesthetized dogs.Study designProspective, randomized, blinded experiment.AnimalsA total of six healthy adult female Beagles aged 1.25 ± 0.08 years and weighing 12.46 ± 1.48 (10.25–14.50) kg.MethodsAnaesthesia was induced with propofol (6–9 mg kg?1) and maintained with 1.8–1.9% end-tidal isoflurane in oxygen. End-tidal CO2 was kept between 35 and 45 mmHg (4.7–6.0 kPa) using intermittent positive pressure ventilation. Heart rate (HR), arterial blood pressure and cardiac output (CO) were monitored. Cardiac output was determined using a LiDCO monitor and the derived parameters were calculated. After baseline measurements, either 10 μg kg?1 romifidine or saline (total volume 1 mL 4.5 kg?1) was injected into the lumbosacral epidural space. Data were recorded for 1 hour after epidural injection. A minimum of 1 week elapsed between treatments.ResultsAfter epidural injection, the overall means (± standard deviation, SD) of HR (95 ± 20 bpm), mean arterial blood pressure (MAP) (81 ± 19 mmHg), CO (1.63 ± 0.66 L minute?1), cardiac index (CI) (2.97 ± 1.1 L minute?1 m?2) and stroke volume index (SI) (1.38 ± 0.21 mL beat?1 kg?1) were significantly lower in the romifidine treatment compared with the overall means in the saline treatment [HR (129 ± 24 bpm), MAP (89 ± 17 mmHg), CO (3.35 ± 0.86 L minute?1), CI (6.17 ± 1.4 L minute?1 m?2) and SI (2.21 ± 0.21 mL beat?1 kg?1)]. The overall mean of systemic vascular resistance index (SVRI) (7202 ± 2656 dynes seconds cm?5 m?2) after epidural romifidine injection was significantly higher than the overall mean of SVRI (3315 ± 1167 dynes seconds cm?5 m?2) after epidural saline injection.ConclusionEpidural romifidine in isoflurane-anaesthetized dogs caused significant cardiovascular effects similar to those reportedly produced by systemic romifidine administration.Clinical relevanceSimilar cardiovascular monitoring is required after epidural and systemically administered romifidine. Further studies are required to evaluate the analgesic effects of epidural romifidine. 相似文献
40.
Tim S. Bugni Cynthia D. Andjelic Ann R. Pole Prem Rai Chris M. Ireland Louis R. Barrows 《Fitoterapia》2009
A traditional preparation of Parmotrema saccatilobum (Taylor) Hale (Family: Parmeliaceae) is being considered for inclusion into the PNG national drug formulary by the Ministry of Health Taskforce on Traditional Medicines. The lichen preparation is traditionally used in the Milne Bay province of Papua New Guinea for analgesic and anti-inflammatory activities. A hexane extract of P. saccatilobum yielded the principle components atranorin and chloroatranorin. Atranorin and chloroatranorin were tested in a COX-1 and -2 enzyme inhibition assay, which showed that atranorin inhibited COX-1 in a dose dependent manner and suggests partial inhibition by atranorin and chloroatranorin of COX-2 and COX-1, respectively. 相似文献