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排序方式: 共有416条查询结果,搜索用时 15 毫秒
1.
This paper asks whether the technological development of a nation reduces the inter‐regional hierarchy in knowledge flow. We examine two scenarios that are the alternative to each other. The first is what we call the globalization of regional innovation system/weakening of inter‐regional hierarchy scenario: As many regions develop their niches in the global economy, the national “anchor” region loses its relative importance as the importer and distributor of new knowledge, rendering the domestic inter‐regional hierarchy less significant as a result. The second scenario is the globalization of national innovation system/persistence of inter‐regional hierarchy. The nation’s traditional anchor region becomes even more active in importing technology and distributing it to other regions of the country. To test which scenario is closer to reality, we employ social network metrics to analyse inter‐regional technology diffusion networks using Chinese patent licensing data for the 1998–2013 period. Our findings support the second scenario, showing that the influence of the traditional anchor region persists in the hierarchical network structure as new cities enter the network. We found five anchor regions: the three usual suspects—Beijing, Shanghai and Shenzhen—plus two that were slightly less expected—Dongguan and Suzhou. 相似文献
2.
Tae-Hyun Kim Young-Woo Park Jae-Sang Ahn Jeong-Taek Ahn Se-Eun Kim Man-Bok Jeong Min-Su Seo Kyung-Sun Kang Kang-Moon Seo 《Journal of veterinary science (Suw?n-si, Korea)》2013,14(1):61-67
This study was performed to evaluate the effects of conditioned media (CM) from human amniotic epithelial cells (HAECs) on the corneal wound healing process. Eighteen rabbits (36 eyes) were used and randomly assigned to three groups according treatment: CM from HAECs (group 1), vehicle alone (group 2), and saline (group 3). Corneal alkali injuries were induced with 1 N sodium hydroxide. Each reagent used for treatment evaluation was injected into the dorsal bulbar subconjunctiva and the area of the corneal epithelial defect was measured every other day. Two animals from each group were euthanized at a time on days 3, 7, and 15, and the cornea was removed for histological examination. The sum of the epithelial defect areas measured on day 0 to day 6 as well as day 0 to day 14 in group 1 was significantly smaller than those of other groups. Histological examination revealed that the group 1 corneas had less inflammatory cell infiltration and showed more intact epithelial features compared to the other groups. These results suggest that CM from HAECs promote corneal wound healing in rabbits. 相似文献
3.
Yasuhisa Kuginuki Hiroaki Yoshikawa Masashi Hirai 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(4):327-332
The differential hosts of Williams (1966) and the European Clubroot Differential (ECD) (Buczacki et al., 1975) have been used commonly to identify populations of Plasmodiophora brassicae, which causes clubroot disease in Brassica crops. However, some of these hosts showed intermediate and fluctuating scores to most populations from Japan. Therefore, these hosts could not be used to provide a clear classification in Japan. We have tried to clarify the genetic diversity in pathogenicity of P. brassicae in Japan using Japanese clubroot-resistant (CR) F1 hybrid (F1) cultivars and lines of Brassica rapa. The responses of some CR F1 cultivars were very clear. Four groups of field populations in Japan were recognized using the CR F1 cultivars. The clear response obtained here may depend largely on the genetic purity of the F1 cultivars. Moreover, it is possible to classify some of these Japanese populations into the same race using the Williams set and ECD 01 to ECD 05. The present differential hosts may be useful in the study of European populations of P. brassicae. The response of the differential hosts suggests that there are several major CR genes in B. rapa. It is suggested that pyramiding CR genes would be useful in breeding CR cultivars that can overcome the breakdown of the present CR cultivars of Chinese cabbage. 相似文献
4.
In this study, changes in total factor productivity of 12 Korean offshore fisheries between 1997 and 2009 were estimated through
the Malmquist productivity index, which is a nonparametric method. Also, the cause of such changes in productivity of each
fishery was analyzed more specifically by segmenting into factors for technological progress and technical efficiency. As
a result of this analysis, the total factor productivity change of the entire offshore fisheries was −6.0 %. Changes in the
technical efficiency and technological level factors, respectively, contributed 0.2 and −6.2 % to this rate of decrease in
total factor productivity; that is, inactivity of technological progress led to the decrease in productivity of the offshore
fisheries. In addition, technological progress and technical efficiency were found to differently influence the change in
total factor productivity of each fishery. In order for each fishery to improve productivity, better rational fisheries management
policies by the government and efforts by the fishing industry and individual fishing business units must accompany factors
that promote productivity increase. 相似文献
5.
Anushka Upamali Rajapaksha Meththika Vithanage Sang Soo Lee Dong-Cheol Seo Daniel C. W. Tsang Yong Sik Ok 《Journal of Soils and Sediments》2016,16(3):889-895
Purpose
Sulfamethazine (SMT) is increasingly detected in environmental matrices due to its versatile use as antibiotics. We aimed to investigate the benefits and roles of steam activation of biochars with respect to SMT sorption kinetics and equilibrium sorption.Materials and methods
Biochars were produced from burcucumber plant and tea waste using a pyrolyzer at a temperature of 700 °C for 2 h. The biochar samples were treated with 5 mL min?1 of steam for an additional 45 min for post-synthesis steam activation. The SMT sorption on the unmodified and steam activated biochars were compared.Results and discussion
The time taken to reach equilibrium was significantly less for steam activated biochars (~4 h) than non-activated biochars (>24 h). Up to 98 % of SMT could be removed from aqueous solutions by steam activated biochars. The sorption kinetic behaviors were well described by the pseudo-second model and SMT sorption rates of steam activated biochars (k 2?~?1.11–1.57 mg g?1 min?1) were significantly higher than that of the unmodified biochars (k 2?~?0.04–0.11 mg g?1 min?1) because of increased availability of accessible porous structure with averagely larger pore diameters. Moreover, the equilibrium sorption on the unmodified biochars was significantly influenced by increasing solution pH (~30–50 % reduction) because of speciation change of SMT, whereas steam activated biochars manifested much stronger sorption resilience against pH variation (~2–4 % reduction only) because the enhanced porosity offset the effect of unfavorable electrostatic repulsion.Conclusions
The observed features of steam activated biochars would render their applications more versatile and reliable in field throughout changeable environmental conditions.6.
Park BK Lyoo KS Park YH Koh JH Seo K 《Journal of veterinary science (Suw?n-si, Korea)》2002,3(4):315-319
To determine the immune responses in pigs to hog cholera virus after treatment with an ionized alkali mineral complex (IAMC), 40 healthy pigs (28-32 days old) from a commercial swine farm were purchased and housed into 4 groups (n=10 each). All pigs were vaccinated intramuscularly (1 ml) with an attenuated live hog cholera virus (HCV, LOM strain) at 28-32 days old and challenged with a virulent hog cholera virus at 8 weeks after vaccination. Each group was treated with PowerFeel sprayed diet as 0.05% (w/w) in a final concentration (T-1, n=10), a diet mixed with SuperFeed as 3% (w/w) in a final concentration (T-2, n=10), or a diluted PowerFeel solution (1:500, v/v) as drinking water (T-3, n=10), respectively. A group (n=10) served as a non-treated control. Proportions of expressing CD2+ and CD8+ cells increased significantly (p<, 0.05) at 8-week post-application. Mean antibody titers of each group against HCV gradually increased to higher levels after vaccination and with challenge of the virulent virus. In conclusion, the IAMC-treated diets can be helpful for the improvement of growth in pigs with proper vaccination program, while the IAMC-treated diets have no effects on the clinical protection against hog cholera. 相似文献
7.
8.
9.
An 8-week feeding experiment was conducted to investigate the effects of different dietary macronutrient level and feeding
frequency on the growth, feed utilization, and body composition of juvenile rockfish. Triplicate groups of fish (body weight
of 4.1 g) were fed the experimental diets containing either high levels of carbohydrate (HC, 35%), lipid (HL, 13%), or protein
(HP, 55%) at different feeding frequencies (twice daily, once daily, and once every 2 days). Weight gain was affected by feeding
frequency but not by dietary composition. Weight gain of fish fed the diets once every 2 days was significantly (P < 0.05) lower than that of other groups. Daily feed intake and energy intake were affected by both dietary composition and
feeding frequency. Daily feed intake of fish fed the HC diet was significantly (P < 0.05) higher than that of fish fed the HL and HP diets at the same feeding frequency. Feed efficiency and protein efficiency
ratio were affected by both dietary composition and feeding frequency and decreased with increasing feeding frequency in the
same dietary composition. Feed efficiency and protein efficiency ratio of fish fed the HC diet were significantly (P < 0.05) lower than those of fish fed the HL diet at the same feeding frequency. Whole-body lipid content of fish fed the
HL diet was significantly (P < 0.05) higher than that of fish fed the HC and HP diets at the same feeding frequency. These results indicate that an increase
of dietary lipid level compared with dietary carbohydrate level may have the advantage of a protein-sparing effect at same
feeding frequency, and a once-daily feeding regime is more effective than twice daily or one feeding every 2 days to improve
growth performance of juvenile rockfish grown from 4 to 21 g. 相似文献
10.
Jeong MB Kim YJ Yi NY Park SA Kim WT Kim SE Chae JM Kim JT Lee H Seo KM 《Veterinary ophthalmology》2007,10(6):376-379
OBJECTIVE: To examine the feasibility and accuracy of a handheld rebound tonometer, TonoVet, and to compare the intraocular pressure (IOP) readings of the TonoVet with those of an applanation tonometer, TonoPen XL, in normal Eurasian Eagle owls. ANIMALS STUDIED: Ten clinically normal Eurasian Eagle owls (20 eyes). PROCEDURES: Complete ocular examinations, using slit-lamp biomicroscopy and indirect ophthalmoscopy, were conducted on each raptor. The IOP was measured bilaterally using a rebound tonometer followed by a topical anesthetic agent after 1 min. The TonoPen XL tonometer was applied in both eyes 30 s following topical anesthesia. RESULTS: The mean +/- SD IOP obtained by rebound tonometer was 10.45 +/- 1.64 mmHg (range 7-14 mmHg), and by applanation tonometer was 9.35 +/- 1.81 mmHg (range 6-12 mmHg). There was a significant difference (P = 0.001) in the IOP obtained from both tonometers. The linear regression equation describing the relationship between both devices was y = 0.669x + 4.194 (x = TonoPen XL and y = TonoVet). The determination coefficient (r(2)) was r(2) = 0.550. CONCLUSIONS: The results suggest that readings from the rebound tonometer significantly overestimated those from the applanation tonometer and that the rebound tonometer was tolerated well because of the rapid and minimal stress-inducing method of tonometry in the Eurasian Eagle owls, even without topical anesthesia. Further studies comparing TonoVet with manometric measurements may be necessary to employ rebound tonometer for routine clinical use in Eurasian Eagle owls. 相似文献