全文获取类型
收费全文 | 541篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
林业 | 32篇 |
农学 | 49篇 |
基础科学 | 7篇 |
111篇 | |
综合类 | 21篇 |
农作物 | 45篇 |
水产渔业 | 30篇 |
畜牧兽医 | 200篇 |
园艺 | 11篇 |
植物保护 | 54篇 |
出版年
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 24篇 |
2020年 | 21篇 |
2019年 | 20篇 |
2018年 | 35篇 |
2017年 | 31篇 |
2016年 | 22篇 |
2015年 | 12篇 |
2014年 | 15篇 |
2013年 | 53篇 |
2012年 | 22篇 |
2011年 | 41篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 20篇 |
2007年 | 21篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 12篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1972年 | 4篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有560条查询结果,搜索用时 15 毫秒
41.
Onur Yilmaz Mehmet Kizilaslan Yunus Arzik Sedat Behrem Nezih Ata Orhan Karaca Cengiz Elmaci Ibrahim Cemal 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2022,139(1):26-39
Sheep are considered as a major contributor of global food security. Moreover, sheep preweaning growth traits as well as in vivo carcass composition traits such as ultrasonic measurements of Longissimus dorsi muscle depth (UMD) and back-fat thickness (UFD) are crucially important indicators of meat yield and hot carcass composition. Despite their relative importance for productivity and profitability of a sheep production system, detected QTL for these traits are quite scarce. Therefore, we implemented GWAS for these traits using animal mixed model-based association approach provided by GenABEL in Esme sheep. Three genome-wide and 14 individual chromosome-wide associated SNPs were discovered. As a result, ESRP1, LOC105613082, ZNF641, DUSP5, TEAD1, SMOX, PTPRT, RALYL, POM121C, PHIP, LOC101106051, ZIM3, PEG3, TRPC7, FBXL4, LOC105610397, LOC105616489 and DNAAF2 were suggested as candidates. Some of the discovered genes and involved pathways were already annotated to contribute growth and development in various species including human, mice and cattle. All in all, the results of this study are expected to strongly contribute to shed a light on the underlying molecular mechanisms behind growth and carcass composition traits, with potential implications on studies aiming faster genetic improvement, targeted low-resolution SNP panel designs and genome-editing studies. 相似文献
42.
The development, fecundity and survival ofStethorus gilvifrons Mulsant (Coleoptera: Coccinellidae) fed onTetranychus cinnabarinus Boisduval (Acari: Tetranychidae) were recorded at three constant temperatures (20, 25 and 30±1°C) and 50±10% relative humidity, under two photoperiods (16:8 L:D and 8:16 L:D) produced using artificial light (4000 lux). The development rate for the egg stage (r[Te]) increased linearly with increasing temperature (r[Te]=0.0132*T ? 0.0955; R2=0.95). The theoretical egg-development threshold was estimated to be 7.24°C; 75.75 degree-days (DD) were required for hatching. The total development time (r[Tt]) also decreased linearly with increasing temperature (r[Tt]=0.0039*T ? 0.0325; R2=0.98). The development threshold was estimated to be 8.33°C and full development from egg to adult required 256.41 DD. Higher temperatures resulted in a shorter generation time (T 0) and decreased net reproductive rate (R 0). The length of the previposition and postoviposition period, as well as longevity, decreased significantly with increasing temperature under both photoperiods. The oviposition and postoviposition periods, longevity, and total fecundity were not significantly affected by photoperiod. The values of both the intrinsic rate of increase (r m ) andR 0 were highest under the long-day photoperiod at 25°C. The mortality rate was lowest at 20°C under the short-day photoperiod. Of the conditions tested, the optimum temperature for rearingS. gilvifrons was 25°C and the optimum photoperiod was 16:8 L:D. 相似文献
43.
Khalid M. Fararh Adel K. Ibrahim Yakot A. Elsonosy 《Research in veterinary science》2010,88(3):400-404
The aim of this study was to examine the effect of glycemic control using thymoquinone (TQ) on energy metabolism related enzymes in leukocytes of streptozotocin (STZ)-induced diabetic rats. The treatment of both TQ and insulin commenced 4 weeks after induction of diabetes. Plasma glucose, cholesterol and triglycerides levels were significantly reduced after TQ treatment, whereas immunoreactive insulin (IRI) showed significant increase. The activities of malate dehydrogenase (MDH) in cytosolic and mitochondrial fractions of peripheral blood leukocytes were significantly higher in rats treated with TQ and insulin as compared to that in diabetic controls. On the other hand the activities of lactic dehydrogenase (LDH) showed no significant changes between groups. ML ratio (cytosolic MDH/LDH specific activity ratio) was restored to those in the control rats. The results of this study demonstrate that TQ significantly increased insulin level and the activities of cytosolic and mitochondrial MDH in leukocytes of STZ-diabetic rats. 相似文献
44.
Ibrahim G. Rubeiz 《Journal of plant nutrition》2013,36(2):269-273
The response of greenhouse cucumber (Cucumis sativus L. cv. Lolita) to nitrogen (N), phosphorus (P) and potassium (K) fertilizers on a soil high in available P and K was studied during 1986. The greenhouses were located in the Beqa Valley, central Lebanon, and their soil chemical properties before planting were: NO3‐N = 52 ppm, P(NaHCO3 ext.) = 100 ppm, K (ammonium acetate ext.) = 650 ppm, ECe = 1.6 dS/m, pH = 7.5. Nitrogen at 200 kg/ha, P at 85 kg/ha and K at 150 kg/ha were applied in the following combinations: N, N+K, N+P+K and an unfertilized control. The rates were split into four equal weekly applications starting on the fourth week after transplanting the seedlings to the greenhouse. The treatments were applied through the drip irrigation system of the greenhouses. Fruit yield over the two months of harvest was highest in plants receiving N alone, which yielded 57 ton/ha. Yields of the plots receiving N+K, N+P+K and the control were 55.0, 54.0 and 39.5 ton/ha, respectively. Yield during the first month of harvest was comparable in all fertilized treatments and was substantially higher than the control. 相似文献
45.
Elshymaa A. Abdelnaby Ibrahim A. Emam Aya M. Fadl 《Reproduction in domestic animals》2021,56(5):764-774
This study aimed to determine the usefulness of colour and pulsed Doppler modes for the accurate diagnosis of donkeys suffering from subfertility to determine whether testicular vascularity assessment could be an indicator for sperm functionality. The study sample was composed of 10 male donkeys with normospermia (control group) and 10 donkeys with hypospermia. Animals underwent scrotal circumference measurement, testicular Doppler examination, seminal evaluation, blood sampling and hormonal assay. Semen volume and concentration were significantly (p ≤ .05) lower in the subfertile group (30.25 ± 1.22 ml and 89.44 ± 2.55 × 106/ml) as compared with the control group (82.76 ± 1.65 ml and 452.78 ± 1.25 × 106/ml), and total sperm/ejaculation was significantly (p ≤ .05) higher in the normal donkeys (28.30 ± 2.32 × 109/total ejaculated) as compared with the subfertile group. Intratesticular coloured area showed a marked decline in the hypospermic males. There was no significant difference between the two groups in testosterone level, although the normal group showed an increase in nitric oxide metabolites. Both Doppler indices of the three branches of the testicular artery were elevated significantly (p ≤ .05) in abnormal donkeys, whereas Doppler peak systolic and end-diastolic velocities were increased in the normal group. Male donkeys with subfertility demonstrated lower arterial vascularity parameters in the form of intratesticular coloured area and blood flow rate; therefore, the most optimal parameters for differentiating subfertile hypospermic from normospermic donkeys were found to be the two Doppler indices, velocities parameters, testicular blood flow rate and nitric oxide levels. 相似文献
46.
Effect of High‐Molecular‐Weight Glutenin Subunit Allelic Composition on Wheat Flour Tortilla Quality
Tom O. Jondiko Novie J. Alviola Dirk B. Hays Amir Ibrahim Michael Tilley Joseph M. Awika 《Cereal Chemistry》2012,89(3):155-161
Wheat cultivars possessing quality attributes needed to produce optimum quality tortillas have not been identified. This study investigated the effect of variations in high‐molecular‐weight glutenin subunits encoded at the Glu‐1 loci (Glu‐A1, Glu‐B1, and Glu‐D1) on dough properties and tortilla quality. Flour protein profiles, dough texture, and tortilla physical quality attributes were evaluated. Deletion at Glu‐D1 resulted in reduced insoluble polymeric protein content of flour, reduced dough compression force, and large dough extensibility. These properties produced very large tortillas (181 mm diameter) compared with a control made with commercial tortilla wheat flour (161 mm). Presence of a 7 + 9 allelic pair at Glu‐B1 increased dough strength (largest compression force, reduced extensibility, and small‐diameter tortillas). Deletion at Glu‐A1 produced large tortillas (173 mm) but with unacceptable flexibility during storage (score <3.0 at day 16). In general, presence of 2* at Glu‐A1, in combination with 5 + 10 at Glu‐D1, produced small‐diameter tortillas that required large force to rupture (tough texture). Presence of 2 + 12 alleles instead of 5 + 10 at Glu‐D1 produced tortillas with a good compromise between diameter (>165 mm) and flexibility during storage (>3.0 at day 16). These allele combinations, along with deletion at Glu‐D1, show promise for tortilla wheat development. 相似文献
47.
Pistacia is a common wild plant in the Southeast Anatolia part of Turkey. The experiment was planned to screen and select the most suitable arbuscular mycorrhizae (AM) for enhancing Pistacia species seedling growth by improving phosphorus (P) and zinc (Zn) uptake. This study was carried out under greenhouse condition at the Department of Soil Science, Çukurova University, Adana, Turkey. Two genotypes from each of P. vera (cvs ‘Siirt’ and ‘Kirmizi’), P. eurycarpa, P. atlantica, and P. terebinthus species were tested with ten different mycorrhizal species. Plants were grown in a growth medium with a mixture of sand, soil and compost with 6:3:1 ratio, respectively. Seedling plants were harvested after eight months and transplanted to pots. There were significant differences between Pistacia species in growth, nutrient uptake and the percentage of mycorrhizal infection. Also mycorrhizal species were different in terms of enhancing plant growth and nutrient uptake. The results were that Siirt, Genotype 08, 11, 13, and 14 gave a high response to the mycorrhizal inoculation and Glomus clarium gave the best improvements in growth and nutrition, resulting in greater plant biomass and Zn and P uptake. Following this, G. etunicatum, G. intraradices, G. caledonium, and G. mosseae species were effective species. In general, G. mosseae and G. fasciculatum mycorrhizae enhanced plant growth; G. clarium was the most efficient species in terms of P and Zn uptake. It has been concluded that these mycorrhizae species significantly enhance the Pistacia plant growth and nutrient uptake. Also using AM fungi in the pistachio nursery should be taken into consideration for better seedling production. Further work needs to be done to determine how much inoculum is needed for sufficient inoculation and how the mycorrhizal seedlings can be adapted under field conditions especially under drought and high calcareous marginal soil conditions. 相似文献
48.
Fahim Fawzia A. Fleita Daisy H. Ibrahim Abdallah M. El-Dars Farida M. S. 《Water, air, and soil pollution》2001,127(1-4):205-226
A fish canning facility processes 1900–2000 tons of mackerel and sardine annually at arate of 10–15 tons per day for a total of 200 days yr-1. This factory generates an average of 20 m3 of industrial wastewaters per day. The objective of our study, which was carried out on a bimonthly basisfrom December 1995 to November 1996, was to determine the overall pollutant load associated with this effluent in relation to the applicable Egyptian Standards and to propose methods for pollutant load reduction before discharging it to the local sewer. The methods were to benefit through the recovery of wasted organic load and transform it into an environmentally safe residue amenable for either immediate reuse or final disposal thereafter. Five chemical coagulation/flocculation treatments were tried using ferric chloride, alum, lime, ferric chloride and lime, and alum and lime. The best method involved the use of FeCl3 and Ca(OH)2 (0.4 g Fe L-1 and 0.2 g Ca L-1, respectively) which reduced the average influent BOD5 from 989 to 204 mg L-1, the COD from 1324 to 320 mg L-1, TSS from 4485 to 206 mg L-1, total protein content from 812 to 66 mg L-1 and oil and grease from 320 to 66 mg L-1. The separated dried precipitate averaged 50 g L-1 which was found to contain 40% by weight recovered protein and 20% recovered fat. The solid was ideal for on-site reprocessing as animal feed. As well, the final effluent, if not discharged to the area sewer, was safe for controlled use in some irrigation applications or forestry projects at the desert area surrounding the factory. 相似文献
49.
Soil structure is determined by the arrangement of particles in soil and the particles of sand, silt, and clay bind together into aggregates of various sizes by organic and inorganic materials. Structural stability which is the ability of the aggregates and pores to remain intact when subjected to stress, markedly affects crop production and soil erosion (Tisdall 1996). Since water, either directly as rainfall or as surface runoff is the main agent of aggregate breakdown, in the analyzes of stable soil aggregation, the term water-stable aggregation is generally used (Lynch and Bragg 1985). Water-stable aggregates have been divided into micro aggregates < 0.25 mm dia.) and macro aggregates (> 0.25 mm dia.) (Edwards and Bremner 1967; Tisdall and Oades 1982). Microaggregates show a relatively high stability against physical disruption (Edwards and Bremner 1967). On the other hand, macro aggregates are sensitive to soil management (Tisdall and Oades 1982). There are many reports on the relationships between the aggregate stability and the soil physicochemical properties. For example, significant correlations were found between the aggregate stability and the amounts of organic C (Tisdall and Oades 1982), total N, and carbohydrates or the CEC (Chaney and Swift 1984). However, most of these studies were conducted in non-volcanic ash soils. Volcanic ash soils are widely distributed in Japan and are very important soils for crop production. The objective of this study was, therefore, to obtain more information on the relationship between the degree of macro aggregation and the soil physicochemical properties in non-volcanic and volcanic ash soils. 相似文献
50.
Ashton Lim Suelee Sharifah Nur Munirah Syed Hasan Faradiella Mohd Kusin Ferdaus Mohamat Yusuff Zelina Zaiton Ibrahim 《Water, air, and soil pollution》2017,228(4):158
Phytoremediation using vetiver grass (Vetiveria zizanioides) has been regarded as an effective technique for removing contaminants in polluted water. This study was conducted to assess the removal efficiency of heavy metals (Cu, Fe, Mn, Pb, Zn) using vetiver grass (VG) at different root lengths and densities and to determine metals uptake rate by plant parts (root and shoot) between treatments (low and high concentration). Removal efficiency for heavy metals in water by VG is ranked in the order of Fe>Pb>Cu>Mn>Zn. Results showed that VG was effective in removing all the heavy metals, but removals greatly depend on root length, plant density and metal concentration. Longer root length and higher density showed greater removals of heavy metals due to increased surface area for metal absorption by plant roots. Results also demonstrated significant difference of heavy metals uptake in plant parts at different concentrations indicating that root has high tolerance towards elevated concentration of heavy metals. However, the effects were less significant in plant shoot suggesting that metals uptake were generally higher in root than in shoot. The findings have shown potential of VG in phytoremediation for heavy metals removal in water thus providing significant implication for treatment of metal-contaminated water. 相似文献