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101.
改善生态环境是山西实现可持续发展的关键   总被引:4,自引:2,他引:2  
石虹 《水土保持研究》2001,8(2):150-152
中国科学院对全国31个行政区的可持续发展能力排队结果表明:山西位第26位,人均国内生产总值4712.3元,为全国平均水平的77.94%,经济明显落后于全国水平.如何改变这种局面,运用生态学原理,在分析山西生态环境的基础上,指出山西实现可持续发展的前提在于改善生态环境,并提出改善山西生态环境的对策.  相似文献   
102.
西部生态项目区可持续发展研究   总被引:1,自引:0,他引:1  
随着西部地区具有样板功能的生态示范县(区)域建设,即将面临着区域生态安全稳定和经济持续发展问题;如何统一经济与生态两个系统的协调运行,在生态环境建设措施的规划配置和组织实施上,一方面要更新观念,提高认识,采纳自然、社会和经济多学科多领域的专家进行综合分析评估,提出区域合理的经济发展模式,并结合非农领域延伸的观念,确定区域生态经济协调发展的可行性规划和实施方案。优先考虑事关区域人民生存与发展的优势产业化开发,以尽快优势产品开发,找准突出的产业经济,来弥补大面积退耕后的农村经济亏损;另一方面,建立健全西部生态  相似文献   
103.
Choices in project approach affect the continuation of soil and water conservation (SWC) after project withdrawal, and thus the sustainability and cost effectiveness of the project. A SWC project was carried out in southern Mali between 1986 and 1998. Its features were the promotion of cheap and simple SWC measures, a participatory village extension approach with limited use of incentives, and the incorporation of the SWC programme in an existing Malian extension service. By 2000, farmers in half the 5000 villages in southern Mali had been trained in SWC. By 2002, erosion‐control measures had been installed in 94 per cent of the villages in southern Mali by 46 per cent of the farmers and in 15 per cent of the fields. Though external donor support has stopped, farmer adoption is steadily continuing and spreading to untargeted villages. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
104.
Fishing sustainably is a fundamental problem in tropical regions where diverse fisheries and scarce fisheries information challenges efforts to make reliable estimates and associated policies. To improve evaluations and decisions, we compared the predictions of six surplus production models calibrated using various permutations of fisheries‐dependent data with a benchmark model. The benchmark model was built from fisheries‐independent estimates of r and K, tested against rates of change in Kenyan reef fisheries and found to be accurate. Comparisons with the benchmark model were made with fisheries‐dependent equilibrium and non‐equilibrium models, fixing or not fixing r and K, pooled versus site averaged solutions, and rising, falling, and pooled fishing effort over time. Evaluations indicate high variability in MMSY predictions and notable overestimates of MMSY (~75%) and effort (~210%) for Fox and Schaefer equilibrium models. Non‐equilibrium models had high failure rates (~25%) but successful fits performed better and indicated smaller overestimates (16%) for site‐level evaluations. The Pella–Tomlinson model was most accurate (MMSY = 5.6 ± 0.60 (SD) tonnes/km2/year) and best‐fit rK relationships also aligned well with ecoregional data on K and short‐term yields. Future efforts are advised to pool site data, use conservative recruitment values (z = 0.8), and collect data across times of both rising and falling effort. Recommended methods and subsequent adjustments of the benchmark model should improve local and ecoregional scale MMSYs. The benchmark model was calibrated to estimate MMSY in fished seascapes, but to conserve species with slower life histories, we suggest modifications to limit MMSYs to between 1.8 and 3.2 tonnes/km2/year.  相似文献   
105.
甘肃省康乐县集全县之力发展肉牛产业,努力打造甘肃肉牛强县。在肉牛产业培育中,不断创新和完善发展机制,通过完善政策配套、政府投入、担保平台、利益联结、打造品牌、市场建设等六大机制,使肉牛产业保持持续快速发展。  相似文献   
106.
Abstract

Field experiments were conducted to investigate nitrogen use efficiency and performance of maize (Zea mays L.) cultivars as influenced by calcium carbide (CaC2) and nitrogen (N) rates in a derived Savanna (2016 and 2017). Maize cultivars {SUWAN-I [open pollinated variety (OPV)] and OBA SUPER II (hybrid)}, rates of N (0, 60 and 90?kg ha?1) and CaC2 (0, 30 and 60?kg ha?1), were arranged in split-split plot respectively, fitted into a randomized complete block design in three replicates. N Partial factor productivity (PFPN), Agronomic Use Efficiency (both years) and Apparent recovery of N (2017) increased in the order 60?>?90?>?0?kg N ha?1, except N Internal use efficiency which was in the order 0?>?60?>?90?kg N ha?1 (2017). Grain yield increased with increasing rates of N in both years. OBA SUPER-II had significantly higher grain yield than SUWAN-I (2017). Similar pattern was observed on number of grains per cob, dry cob weight, PFPN and plant height (2017). Conversely in 2016, grain, total and shoot N uptakes were significantly higher in SUWAN-I than OBA SUPER-II. Increasing application of CaC2 increased grain N uptake and number of grains per cob. Number of leaves and stem girth increased in the order of 60?>?0?>?30?kg?CaC2 ha?1. Increased grain yield with N rates could be associated with NHI and N use efficiency. These evidences suggested that hybrid maize performed better than OPV in a derived Savanna.  相似文献   
107.
Cefquinome (CEF) is widely used for veterinary clinical applications because of its broad spectrum and high efficiency. However, frequent administrations are required due to its short elimination half‐life. In this study, cefquinome sulfate gelatin microspheres (CEF‐GMS) were prepared as a sustained‐release formulation using emulsion chemical cross‐linking technique. Physical properties, stability, sustained‐release property in vitro, and pharmacokinetics in pigs were assessed. The morphology of CEF‐GMS showed a good sphericity with porous structure on the surface, and the mean diameter was 8.80 ± 0.78 μm, with 90.60 ± 3.98% of the total in the range of 5–20 μm. There were no significant changes of all estimated indexes in the stability tests. In vitro drug release study showed that the release of CEF from CEF‐GMS was much slower than that from crude CEF in a release medium. Pharmacokinetic characteristics were evaluated following intramuscular administration of CEF‐GMS or Cefquinome sulfate injection (CEF‐Inj) in pigs at a dosage of 4 mg CEF/kg body weight. The plasma drug concentration–time data of CEF‐GMS and CEF‐Inj were both best fitted by two‐compartment models with first‐order absorption, and the elimination half‐life of CEF‐GMS was almost 10 times that of CEF‐Inj. Overall, CEF‐GMS might be used as a sustained‐release formulation of CEF for veterinary clinical applications.  相似文献   
108.
Circadian variation of serum concentrations of tylosin in broiler chickens after in-feed medication prompted a comparison study of the serum profiles of this drug after in-feed medication with standard tylosin phosphate (Tprf reference formulation group), and after in-feed medication with a sustained-release pellet formulation (Tpsr group), based on Patent No.MX/a/2012/013222 and PCT/MX2013/000137, in broiler chickens. Six hundred 4-week-old Ross broiler chickens were in-feed medicated with tylosin phosphate at an approximate dose of 25.2 mg/kg/d, based on daily feed consumption values and a final concentration of tylosin in feed of 200 mg/kg of feed. Approximately 2 to 3 mL of blood were obtained per 5 chickens every 2 h, avoiding the sampling of a bird more than once and during 72 h after making medicated feed available for the first time. Serum concentrations of tylosin were determined by HPLC. Gaussian multi-peak regressions were then fitted to serum concentration vs. time profiles. Day by d areas under the serum concentration vs. time profiles (AUC0–24), as well as overall AUC0–72, were statistically higher for the Tpsr group (P < 0.001). Also, maximum serum concentrations obtained and relative bioavailability for the Tpsr formulation were statistically higher (382.8%) as compared to the Tprf group (P < 0.01). Considering the referred improved values of AUC observed in the Tpsr formulation, as well as the fact that tylosin is a time-dependent antibacterial drug, better clinical responses are postulated with this pharmaceutical preparation intended for chickens. Tissue deposition studies for this new formulation of tylosin are required.  相似文献   
109.

Objective

To determine the effect of a bimatoprost sustained‐release intracameral implant (Bimatoprost SR) on episcleral venous pressure (EVP) in normal dogs.

Methods

Normotensive beagle dogs were randomized to receive Bimatoprost SR 30 μg (n = 7) or sham injection (needle insertion only, n = 7) in one eye on day 1. EVP was measured with an episcleral venomanometer through day 65. Episcleral aqueous outflow vessels were identified using fluorescence imaging following intracameral injection of indocyanine green in one additional animal. A separate cohort of dogs that had been trained for conscious intraocular pressure (IOP) measurements received Bimatoprost SR 30 μg (n = 8) in one eye; IOP was evaluated through day 66.

Results

Baseline mean EVP was 10.0 mmHg in the Bimatoprost SR group and 10.4 mmHg in the sham group. Eyes treated with Bimatoprost SR exhibited a transient increase in mean EVP that peaked at day 8, followed by a decrease to levels below baseline. From day 29 to day 65, the change in mean EVP from baseline ranged from ?2.4 to ?3.9 mmHg (P < 0.05 vs. sham). Baseline mean IOP in eyes treated with Bimatoprost SR was 14.9 mmHg, and a steady IOP reduction was maintained through day 66. Bimatoprost SR‐treated eyes exhibited a selective, sustained dilation of aqueous outflow vessels that was not observed in sham‐treated eyes.

Conclusions

In normal dogs, Bimatoprost SR was associated with a transient increase in EVP followed by a sustained decrease. Changes in EVP were accompanied by a sustained dilation of aqueous outflow vessels.
  相似文献   
110.
为了提高干旱半干旱地区马铃薯的出苗率和产量,采用田间试验方法进行了“莯润”抗旱营养缓释剂穴施、浸种对马铃薯生长和产量的影响试验,研究了缓释剂固态水施入土壤对马铃薯块茎大小的影响.结果表明,“莯润”抗旱营养缓释剂穴施、浸种极显著地提高了马铃薯的出苗率(p<0.01),都比对照提高了76.2%;马铃薯的植株高度比对照增加21.8%~44.5%,均达到极显著水平(p<0.01),生育前期根冠比偏低比较有利,可以为后期马铃薯块茎的生长和物质的积累提供有利条件;施用缓释剂使马铃薯产量增加12.4%~16.7%,但没达到显著水平(p>0.05).“莯润”抗旱营养缓释剂固态水施入土壤,减少了直径小的马铃薯的数量,增加了直径大者的数量,使得马铃薯块茎的平均直径增大,商品性增加.“莯润”缓释剂提高了马铃薯的出苗率和产量,固态水的使用提高了水分利用率和马铃薯的商品性.  相似文献   
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