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421.
The concentration of the free fatty acid anion linoleate was found to be important for the pro-oxidative activity of metmyoglobin, MbFe(III), and for mixtures of metmyoglobin and hydrogen peroxide, MbFe(III)/H(2)O(2), to yield perferrylmyoglobin, (*)MbFe(IV)=O, whereas for ferrylmyoglobin, MbFe(IV)=O, no concentration effect was noted as studied in linoleate emulsions (pH 7.4 and 25 degrees C). Determination of conjugated dienes using second-derivative absorption spectroscopy, changes in Soret band absorbance, and spin-trapping ESR spectroscopy with alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone (POBN) as the spin trap were used to evaluate the pro-oxidative activity of myoglobins. At a linoleate (LA)/heme protein (HP) ratio of 100, no MbFe(III)-induced linoleate peroxidation was observed, as MbFe(III) was converted to its non-pro-oxidative low-spin derivative, hemichrome, independently of the presence of H(2)O(2). At higher LA/HP ratios, linoleate peroxidation was initiated by the addition of MbFe(III), both in the presence and in the absence of H(2)O(2). This proceeded with denaturation of MbFe(III), as followed by changes in Soret absorption band, which most probably release or expose the heme group to the environment and thereby permit hematin-induced lipid peroxidation. The obtained results show that the mechanism by which MbFe(IV)=O initiates linoleate peroxidation is different from MbFe(III)- and MbFe(III)/H(2)O(2)-initiated linoleate peroxidation. The shift in mechanism between heme protein cleavage of lipid hydroperoxides and hematin-induced lipid peroxidation is discussed in relation to oxidative progress in biological systems and muscle-based foods. 相似文献
422.
Myoglobin-induced lipid oxidation. A review 总被引:1,自引:0,他引:1
An overview of myoglobin-initiated lipid oxidation in simple model systems, muscle, and muscle-based foods is presented. The potential role of myoglobin spin and redox states in initiating lipid oxidation is reviewed. Proposed mechanisms for myoglobin-initiated lipid oxidation in muscle tissue (pH 7.4) and meat (pH 5.5) are evaluated with the purpose of putting forward general mechanisms explaining present observations regarding the catalytic events. 相似文献
423.
Rebecca E. Arnold Caroline J. Langdon Mark E. Hodson Stuart Black 《Pedobiologia》2003,47(5-6):633-639
424.
Maria Gabriela Xavier Oliveira Leandro Nogueira Pressinotti Giovane Spínola Carvalho Mirela Caroline Vilela Oliveira Luisa Zanolli Moreno Carlos Emilio Cabrera Matajira Alessandro Spínola Bergamo Victor Manuel Aleixo Alexandre Caixeta Veiga Elvis de Souza Corsino Ana Paula Guarnieri Christ Maria Inês Zanolli Sato Andrea Micke Moreno Terezinha Knöbl 《Tropical animal health and production》2017,49(4):777-782
The aim of this study was to perform the identification and molecular characterization of Arcobacter cryaerophilus and Arcobacter butzleri isolated from caiman (Caiman yacare), kept at a production farm, in Brazil. Forty fecal samples were analyzed. After isolation and identification, 21/40 strains of A. butzleri and 19/40 strains of A. cryaerophilus were subjected to PCR for potential virulence gene detection. The results of the PCR showed 38/40 strains positive for the cadF, cj1349, ciaB, and tlyA genes, 39/40 strains positive for the pldA gene, and 40/40 strains positive for the mviN gene. None of the strains presented the irgA gene. Hemagglutinin (hecA gene) and hemolysin (hecB) genes were detected in 21/40 and 16/40 strains, respectively. The SE-AFLP showed a great genetic diversity, but some clonally groups were disseminated in various tanks. These data reveal that the strains presented the same virulence traits described from Arcobacter isolated from food-borne disease in humans. 相似文献
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428.
Bosmans T Schauvliege S Gasthuys F Duchateau L Marcilla MG Gadeyne C Polis I 《Veterinary anaesthesia and analgesia》2011,38(2):146-157
ObjectiveTo compare the cardiovascular effects of four epidural treatments in isoflurane anaesthetised dogs.Study designProspective, randomized. experimental study.AnimalsSix female, neutered Beagle dogs (13.3 ± 1.0 kg), aged 3.6 ± 0.1 years.MethodsAnaesthesia was induced with propofol (8.3 ± 1.1 mg kg?1) and maintained with isoflurane in a mixture of oxygen and air [inspiratory fraction of oxygen (FiO2) = 40%], using intermittent positive pressure ventilation. Using a cross-over model, NaCl 0.9% (P); methadone 1% 0.1 mg kg?1 (M); ropivacaine 0.75% 1.65 mg kg?1 (R) or methadone 1% 0.1 mg kg?1 + ropivacaine 0.75% 1.65 mg kg?1 (RM) in equal volumes (0.23 mL kg?1) using NaCl 0.9%, was administered epidurally at the level of the lumbosacral space. Treatment P was administered to five dogs only. Cardiovascular and respiratory variables, blood gases, and oesophageal temperature were recorded at T-15 and for 60 minutes after epidural injection (T0).ResultsMean overall heart rate (HR in beats minute?1) was significantly lower after treatment M (119 ± 16) (p = 0.0019), R (110 ± 18) (p < 0.0001) and RM (109 ± 13) (p < 0.0001), compared to treatment P (135 ± 21). Additionally, a significant difference in HR between treatments RM and M was found (p = 0.04). After both ropivacaine treatments, systemic arterial pressures (sAP) were significantly lower compared to other treatments. No significant overall differences between treatments were present for central venous pressure, cardiac output, stroke volume, systemic vascular resistance, oxygen delivery and arterial oxygen content (CaO2). Heart rate and sAP significantly increased after treatment P and M compared to baseline (T-15). With all treatments significant reductions from baseline were observed in oesophageal temperature, packed cell volume and CaO2. A transient unilateral Horner’s syndrome occurred in one dog after treatment R.Conclusions and clinical relevanceClinically important low sAPs were observed after the ropivacaine epidural treatments in isoflurane anaesthetised dogs. Systemic arterial pressures were clinically acceptable when using epidural methadone. 相似文献
429.
Matteo Campioli Caroline Vincke Mathieu Jonard Vincent Kint Gaston Demarée Quentin Ponette 《Journal of Forest Research》2012,17(1):1-18
Reviews of the current statuses of forests and the impacts of climate change on forests exist at the (sub)continental scale,
but rarely at country and regional levels, meaning that information on causal factors, their impacts, and specific regional
properties is often inconsistent and lacking in depth. Here, we present the current status of forest production and biogeochemistry
and the expected impacts of climate change on them for Belgium. This work represents a case study for the temperate oceanic
zone, the most important bioclimatic zone in northwestern Europe. Results show that Belgian forests are mainly young, very
productive, and have a high C-sequestration capacity. Major negative anomalies in tree vitality were observed in the 1990s
and—as result of disturbances—in the last decade for sensitive species as poplars and European beech. The most severe disturbances
were caused by extreme climatic events, directly (e.g. storms) or indirectly (e.g. insect outbreaks after a mild autumn with
an early/severe frost). Because of atmospheric deposition and soil fertilization (due to the previous use of the land), nutrient
stocks of Belgian forests are likely to sustain the future enhancement in productivity which is expected to follow the increase
in atmospheric CO2 concentration that will occur in years to come. However, in the long term, such (enhanced) forest production is likely to
be limited by nutrient deficiencies at poor sites and by drought for sensitive species such as beech and (particularly) Norway
spruce. Drought conditions will likely increase in the future, but adverse effects are expected on a relatively limited number
of tree species. The potential impacts of windstorms, insects and fungi should be carefully investigated, whereas fires are
less of a concern. 相似文献
430.
Eunyoung Choe Freek van der Meer David Rossiter Caroline van der Salm Kyoung-Woong Kim 《Water, air, and soil pollution》2010,206(1-4):129-137
This study aimed at examining effective sample treatments and spectral processing for an alternate method of soil nitrate determination using the attenuated total reflectance (ATR) of Fourier transform infrared (FTIR) spectroscopy. Prior to FTIR measurements, soil samples were prepared as paste to enhance adhesion between the ATR crystal and sample. The similar nitrate peak heights of soil pastes and their supernatants indicated that the nitrate in the liquid portion of the soil paste mainly responded to the FTIR signal. Using a 0.01-M CaSO4 solution for the soil paste, which has no interference bands in the characteristic spectra of the analyte, increased the concentration of the nitrates to be measured. Second-order derivatives were used in the prediction model to minimize the interference effects and enhance the performance. The second-order derivative spectra contained a unique nitrate peak in a range of 1,400–1,200 cm?1 without interference of carbonate. A partial least square regression model using second-order derivative spectra performed well (R 2?=?0.995, root mean square error (RMSE)?=?23.5, ratio of prediction to deviation (RPD)?=?13.8) on laboratory samples. Prediction results were also good for a test set of agricultural field soils with a CaCO3 concentration of 6% to 8% (R 2?=?0.97, RMSE?=?18.6, RPD?=?3.5). Application of the prediction model based on soil paste samples to nitrate stock solution resulted in an increased RMSE (62.3); however, validation measures were still satisfactory (R 2?=?0.99, RPD?=?3.0). 相似文献