首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   72篇
  免费   5篇
林业   13篇
农学   1篇
基础科学   2篇
  11篇
综合类   5篇
农作物   9篇
水产渔业   8篇
畜牧兽医   25篇
植物保护   3篇
  2022年   2篇
  2021年   1篇
  2020年   4篇
  2019年   4篇
  2018年   7篇
  2017年   7篇
  2016年   5篇
  2015年   2篇
  2014年   2篇
  2013年   5篇
  2012年   10篇
  2011年   6篇
  2010年   6篇
  2009年   1篇
  2008年   2篇
  2007年   3篇
  2006年   2篇
  2005年   6篇
  2003年   1篇
  2002年   1篇
排序方式: 共有77条查询结果,搜索用时 15 毫秒
61.

Background

The aim of this study was to fabricate the poly caprolactone (PCL) aligned nanofiber scaffold and to evaluate the survival, adhesion, proliferation, and differentiation of rat hair follicle stem cells (HFSC) in the graft material using electrospun PCL nanofiber scaffold for tissue engineering applications.

Methods

The bulge region of rat whisker was isolated and cultured in DMEM: nutrient mixture F-12 supplemented with epidermal growth factor. The morphological and biological features of cultured bulge cells were observed by light microscopy using immunocytochemistry methods. Electrospinning was used for production of PCL nanofiber scaffolds. Scanning electron microscopy (SEM), 3-(4, 5-di-methylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, and histology analysis were used to investigate the cell morphology, viability, attachment and infiltration of the HFSC on the PCL nanofiber scaffolds.

Results

The results of the MTT assay showed cell viability and cell proliferation of the HFSC on PCL nanofiber scaffolds. SEM microscopy images indicated that HFSC are attached, proliferated and spread on PCL nanofiber scaffolds. Also, immunocytochemical analysis showed cell infiltration and cell differentiation on the scaffolds.

Conclusion

The results of this study reveal that PCL nanofiber scaffolds are suitable for cell culture, proliferation, differentiation and attachment. Furthermore, HFSC are attached and proliferated on PCL nanofiber scaffolds.Key Words: Nanofiber, Electrospinning, Stem cells, Tissue engineering  相似文献   
62.
Background: The time from sampling to analysis can be delayed when blood samples are shipped to distant reference laboratories or when analysis cannot be readily performed. Objective: The objective of this study was to evaluate the stability of hematologic analytes in blood samples from monkeys, rabbits, rats, and mice when samples were stored for up to 72 hours at 4°C. Methods: Blood samples from 30 monkeys, 15 rabbits, 20 rats, and 30 mice were collected into EDTA‐containing tubes and were initially analyzed within 1 hour of collection using the ADVIA 120 analyzer. The samples were then stored at 4°C and reanalyzed at 24, 48, and 72 hours after collection. Results: Significant (P<.0003) changes in hematologic analytes and calculations included increased HCT and MCV and decreased MCHC and cell hemoglobin concentration mean (CHCM) at 72 hours and increased MPV at 24 hours in monkeys; increased MCV at 72 hours and MPV at 48 hours and decreased monocyte count at 24 hours in rabbits; increased MCV and decreased MCHC, CHCM, and monocyte count at 24 hours in rats; increased MCV, red cell distribution width, and MPV and decreased MCHC, CHCM, and monocyte count at 24 hours in mice. Conclusions: Although most of the changes in the hematologic analytes in blood from monkeys, rabbits, rats, and mice when samples were stored at 4°C were analytically acceptable and clinically negligible, the best practice in measuring hematologic analytes in these animals is timely processing of blood samples, preferably within 1 hour after collection.  相似文献   
63.
64.
Anesthesia in Caspian ponies   总被引:1,自引:0,他引:1  
ObjectiveTo evaluate some of the clinical and laboratory parameters following diazepam–acepromazine, thiopental, and halothane anesthesia in Caspian ponies.Study designProspective experimental trial.AnimalsSix healthy Caspian ponies of both sexes, aged 11 ± 3 years and weighing 318 ± 71 kg.MethodsThe ponies were pre-medicated with diazepam (0.2 mg kg−1) and acepromazine (0.05 mg kg−1) IV. Sodium thiopental 5% was administered IV, 10 minutes later and anesthesia was maintained with halothane in oxygen for 1 hour. Heart and respiratory rates, mean arterial blood pressure, cardiac rhythm, and signs of anesthetic depth were monitored during anesthesia. Hematological and serum biochemical parameters were evaluated before anesthesia and at 1, 2, 3, 24, 48, 72, and 96 hours. Urine specific gravity and cytology were evaluated at the same intervals following anesthesia. Parametric data were analyzed using repeated measures anova.ResultsConsiderable sedation/tranquilization without excitement was achieved following pre-medication. Heart rate significantly increased and mild hypotension occurred during anesthesia. Sinus arrhythmia and second degree AV block occurred in five horses. Respiratory rate decreased during anesthesia, with an accompanying respiratory acidosis. Body temperature also decreased. Recovery was scored ‘good’ in four horses and ‘satisfactory’ in the other two. Blood urea nitrogen concentration was significantly increased at 1–3 hours post-anesthesia. Blood glucose was significantly increased at 48, 72, and 96 hours, and creatine kinase and aspartate aminotransferase were significantly increased at 24 and 48 hours post-anesthesia.Conclusion and clinical relevance This simple anesthetic protocol can be used in Caspian ponies and an acceptable anesthetic with a reasonable recovery can be expected.  相似文献   
65.
Tropical Animal Health and Production - The aim of this study was to investigate the efficacy of dietary endotoxin binders [bentonite (BEN) and Saccharomyces cerevisiae cell wall (SCW)] on...  相似文献   
66.
Time equations are derived for felling with chainsaw, skidding with cable wheeled skidder, loading with grapple hydraulic loader and trucking of logs within a cut-to-length harvesting method. The continuous time study method was applied to collect data for felling, skidding, loading and a transportation model. Multiple regression analysis via SPSS software was applied to develop the time models. Felling time was found to be highly dependent on diameter at breast height. Skidding distance, winching distance, slope of the trail and piece volume were significant variables for the skidding time prediction model. The loading time model was developed considering piece volume. Transportation distance and load volume were used as independent variables in modeling the transportation time. The net production of felling was estimated at 12 trees/h (56.65 m3/h). The net production rates for skidding, loading and traveling averaged 18.51, 41.90 and 3.32 m3/h respectively. The total cost of harvesting from stand to mill was estimated 19.70 €/m3. The skidding phase was the most expensive component of the cut-to-length method. The bucking and delimbing components were less costly than the other logging phases. The results of this study can be used for harvesting planning and productivity optimization.  相似文献   
67.
We investigated the altitudinal variation of Carpinus betulus L. in the Hyrcanian forest using leaf macro-morphological and micro-morphological traits. We collected a total of 1600 leaves from two locations. In each location, we sampled six populations along an altitudinal gradient ranging from 100 m to 1,150 m. We found that trees in the higher elevations have smaller leaf lamina than those in the lower elevations. In contrast, leaf mass per area was high at low altitudes and increased newly at the higher ones. Stomatal dimension was negatively correlated with elevation, while stomatal density was positively correlated with elevation. We also found that two transects showed the same plasticity trend. Leaf area showed the highest plasticity, while the number of veins showed the lowest plasticity. This study shows that altitude, and related temperature and rainfall, represents an important driving force in Carpinus betulus leaf morphological variation. Moreover, our results suggest that leaf area, leaf mass per area and stomatal density could influence the species responses to different ecological conditions.  相似文献   
68.
The objectives of the present study was to investigate the effects of the copper injection and injection timing to pregnant dairy cows at dry period on the hematology, some serum metabolites, health and growth of their calves. Thirty Holstein cows at the dry period were assigned to the three following experimental groups: 1) control (injections of 2.5 ml normal saline), 2) test 1 (125 mg Cu as copper edetate injection at the first week of the dry period) and 3) test 2 (125 mg Cu as copper edetate injection at the third week of the dry period). Ten milliliters of jugular blood was taken from all calves 24–48 h after birth and at 7, 14, 21 and 28 days of age for measuring hematological and biochemical parameters. For evaluation of growth and health, body weight of all of the calves was measured at birth and at the end of the trial, and the health of calves was checked by a technician twice a day and any sign of illness, treatment (if needed) and duration of illness was recorded. Copper treatment was proved to have a significant effect on the counts of WBC (lower in test 2, higher in test 1), lymphocyte (lower in test 2, higher in test 1) and the concentrations of fibrinogen (lower in test 1, higher in test 2), cholesterol (lower in control, higher in test 1) and copper (lower in test 1, higher in test 2) (p < 0.05). Age (sampling time) also influenced most measured parameters (p < 0.05) except values of WBC, neutrophil, monocyte, globulin and concentrations of iron, zinc and copper.  相似文献   
69.
The objectives of this study were to determine the effects of a pre-partum diet with lower than recommended (DCAD = −82 mEq/kg of dietary DM) amounts of anionic salts on metabolism, health, reproductive performance and milk production in dairy cows. Sixty Holstein multiparous cows were enrolled 21 days prior to expected calving date. The animals were randomly assigned to receive one of two rations: 30 cows received anionic ration [−82 mEq (NA + K − Cl − S)/kg of DM] for 21 d to parturition and the other group (n = 30) were fed a usual dry period ration (+192 mEq/kg of DM). Serum samples obtained at days −21, +3 and +21 relative to calving were analyzed for β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFA), glucose, calcium (Ca), inorganic phosphorus, magnesium, chloride, sodium, potassium, cholesterol, urea, creatinine, total protein, albumin, and aspartate aminotransferase (AST). Urine pH declined from 8.4 at 21 d before calving (pre-treatment) to 6.2 at day 7 pre-partum in the treatment group. Repeated-measure mixed model analysis indicated that the concentrations of Ca were significantly increased and creatinine, and AST were significantly decreased by lowering DCAD. The concentrations of BHBA, NEFA and glucose were not affected by treatment. The incidence of milk fever and culling were 5 and 11 times higher in the control group in comparison with the treatment group, respectively. The intervals from calving to first breeding and to pregnancy were not influenced by treatment. There was no group effect on average daily milk yield or fat percentage.  相似文献   
70.
Bovine failure of passive transfer (FPT), defined as inadequate transfer of colostral immunoglobulins from the dam to the calf, has been associated with increased risk in neonatal mortality. Currently, radial immunodiffusion (RID) assay is considered to be the gold standard in determining FPT in serum samples from calves. There are 2 commercial RID assays routinely used for serodiagnosis of FPT in calves: VET-RID and SRID. Discrepancies between results of these RID assays were observed in the authors' laboratory. The objective of this study was to compare 2 commercial RID assays by testing a paired panel of 30 blood samples collected from newborn Holsteins at birth before, and 24 hr after, ingestion of colostrum, a commercial bovine reference serum, and a panel of different concentrations of 2 purified bovine immunoglobulin G (IgG) products. Overall, the results of this study showed a high level of discrepancy and poor agreement between the 2 RID kits. The interassay precision study revealed lower between-run coefficients of variation for the VET-RID kit compared with the SRID kit. The spiking and recovery study using purified bovine IgG products demonstrated that the VET-RID kit more closely approximates the expected concentrations of the purified bovine IgG products, whereas the SRID kit consistently overestimates the concentration of purified bovine IgG products. It was concluded that this may be due to inaccuracies in the internal standards of the SRID kit.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号