全文获取类型
收费全文 | 429篇 |
免费 | 27篇 |
专业分类
林业 | 24篇 |
农学 | 40篇 |
基础科学 | 5篇 |
102篇 | |
综合类 | 30篇 |
农作物 | 23篇 |
水产渔业 | 14篇 |
畜牧兽医 | 160篇 |
园艺 | 13篇 |
植物保护 | 45篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 10篇 |
2019年 | 3篇 |
2018年 | 16篇 |
2017年 | 17篇 |
2016年 | 25篇 |
2015年 | 7篇 |
2014年 | 13篇 |
2013年 | 46篇 |
2012年 | 15篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 27篇 |
2006年 | 26篇 |
2005年 | 8篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 10篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1979年 | 4篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 3篇 |
排序方式: 共有456条查询结果,搜索用时 31 毫秒
81.
ABSTRACT Zinc (Zn) deficiency is the most prevalent nutritional disorder in citrus orchards world over. The management strategy of Zn deficiency today is still governed by the efficacy of two conventionally used methods of Zn supply to plants via soil or foliar fertilization. A field experiment with 12-yr-old ‘Nagpur’ mandarin (Citrus reticulata Blanco) orchard was, therefore, carried out during 2004–07 comparing soil application versus foliar application of Zn, each at three levels viz., 100, 200, and 300 g tree?1 with constant doses of N (600 g tree?1), P (200 g tree?1), K (300 g tree?1), and Fe(60 g tree?1) on Haplustert soil type with reference to response on flowering intensity, fruit set, tree volume, fruit yield, changes in soil fertility/leaf nutrient status, fruit quality, and transformation of native soil Zn fractions. Soil application of Zn at all the three levels, produced significantly higher increase in tree volume over foliar application on equivalent rates viz., T1 (2.53 m3) vs. T4 (2.06 m3) and T2(4.30 m3) vs. T5 (2.23 m3). The yield-determining parameters like flowering and fruit set intensity (no. m?1 shoot length) were, respectively, much higher with soil applied (135.74 and 21.90) than foliar applied Zn (31.20 and 11.6). These observations set the favorable conditions required for yield response, e.g., all the three treatments involving soil application of Zn, T1 (32.1 kg tree?1), T2 (52.6 kg tree?1), and T3 (51.8 kg tree?1) were correspondingly superior over T4 (22.5 kg tree?1), T5 (34.3 kg tree?1), and T6 (42.1 kg tree?1) as foliar application treatments. All the three major fruit quality parameters (juice, acidity, and TSS) were likewise more influenced by soil application than foliar application of Zn. Improvements in soil Zn fractions (mg kg?1) viz., exchangeable Zn (0.25–0.60), complex-Zn (2.71 to 4.86), organically bound Zn (0.86 to 2.0), and Zn-bound to carbonates and acid soluble minerals (2.56–4.96) were observed in response to Zn fertilization with treatments T1–T3. On the other hand, foliar applied Zn treatments (T4–T6) produced no such changes in any of the soil Zn fractions. 相似文献
82.
Sherry Rachel Jacob MB Arunkumar Madhuban Gopal Chitra Srivastava SN Sinha 《Pest management science》2009,65(7):817-822
BACKGROUND: An efficient delivery system for seed‐protectant chemicals is needed in light of several disadvantages of conventional seed treatment methods. This study evaluates the efficacy of film‐coat application in maintaining the persistence and potency of imidacloprid on Lycopersicon esculentum (L.) Mill. seeds after simultaneous storage under ambient and regulated environment in paper and aluminium packages. RESULTS: High‐performance liquid chromatography (HPLC) revealed 0.135 mg kg?1 of herbage material to be the threshold value beyond which absolute control was obtained, and with film coating the latter was achieved even with half‐dosage seed treatment, irrespective of the storage condition. The technique provided early protection to the crop and also nullified the deleterious effects of ambient storage on the persistence and potency of the pesticide. CONCLUSION: Film coating enabled superior pesticide dosage as well as higher biological efficacy to be achieved. Hence, in addition to being an ecofriendly alternative, the technique would be a more economically viable option for storage of treated seeds. Copyright © 2009 Society of Chemical Industry 相似文献
83.
Physiological and Biochemical Responses of Hexaploid and Tetraploid Wheat to Drought Stress 总被引:8,自引:1,他引:7
V. Chandrasekar R. K. Sairam G. C. Srivastava 《Journal of Agronomy and Crop Science》2000,185(4):219-227
An experiment was conducted to investigate the physiological and biochemical responses of two hexaploids viz., C 306 (water stress tolerant) and Hira (water stress susceptible), and two tetraploids, HW 24 (Triticum dicoccum) and A 9‐30‐1 (Triticum durum) wheat genotypes to water stress under pot culture condition. Water stress was imposed for a uniform period of 10 days at 50, 60 and 70 days after sowing (DAS) and observations were recorded at 60, 70 and 80 DAS. Total dry matter and plant height were recorded at harvest. Water stress caused a decline in relative water content (RWC), chlorophyll and carotenoid content, membrane stability and nitrate reductase activity and increased accumulation of proline at all stages and abscisic acid (ABA) at 80 DAS in all the genotypes. Both the tetraploids showed a lower reduction in RWC and highest ABA accumulation under water stress. Among the hexaploids Hira showed the most decline in RWC and the lowest ABA accumulation. The tetraploids also showed comparatively higher carotenoid content and membrane stability, closely followed by C 306, while Hira showed the minimum response under water stress. Nitrate reductase activity and chlorophyll content under irrigated conditions were highest in Hira but under water stress the lowest per cent decline was observed in C 306, followed by HW 24, A 9‐30‐1, and Hira. Proline accumulation under water stress conditions was highest in hexaploids C 306 and Hira and lowest in tetraploids HW 24 and A 9‐30‐1. Tetraploids HW 24, followed by A 9‐30‐1 maintained higher plant height and total dry matter (TDM) under water stress and also showed a lower per cent decline under stress than hexaploids C 306 and Hira. From the results it is clear that proline accumulation did not contribute to better drought tolerance of tetraploids than hexaploids. It is also apparent that water stress tolerance is the result of the cumulative action of various physiological processes, and all the parameters/processes may not be positively associated with the drought tolerance of a particular tolerant genotype. 相似文献
84.
Akhouri Nishant Bhanu Mahendra Narain Singh Kartikeya Srivastava 《Plant Breeding》2019,138(2):202-206
Six intervarietal crosses involving two resistant and three susceptible genotypes of mungbean were attempted with the objectives to determine the mode of inheritance of gene‐specific Mungbean Yellow Mosaic Virus (MYMV) resistance. An infector row technique along with artificial inoculation was used for evaluating parents, F1, F2 and F3 plants for MYMV resistance. Disease scoring for MYMV indicated that F1s were highly susceptible as were the susceptible parents while resistant parent exhibited resistant reaction. The F2 progeny segregated in the ratio of 9 S:3 MS:3 MR:1 R suggesting that the resistance was governed by digenic recessive genes (rm1 and rm2). When one gene (rm1) was present in the homozygous recessive condition in different plants, it conferred moderately susceptible (MS) reaction, whereas when other gene (rm2) was in homozygous condition, moderately resistant (MR) reaction was obvious. When both genes (rm1 and rm2) were present together in the homozygous recessive condition, resistant reaction (R) was observed. The F2 segregation explained on the basis of phenotypic expression was further confirmed by F3 segregation. 相似文献
85.
Cattle control body temperature in a narrow range over varying climatic conditions. Endogenous body heat is generated by metabolism, digestion and activity. Radiation is the primary external source of heat transfer into the body of cattle. Cattle homeothermy uses behavioural and physiological controls to manage radiation, convection, conduction, and evaporative exchange of heat between the body and the environment, noting that evaporative mechanisms almost exclusively transfer body heat to the environment. Cattle control radiation by shade seeking (hot) and shelter (cold) and by huddling or standing further apart, noting there are intrinsic breed and age differences in radiative transfer potential. The temperature gradient between the skin and the external environment and wind speed (convection) determines heat transfer by these means. Cattle control these mechanisms by managing blood flow to the periphery (physiology), by shelter-seeking and standing/lying activity in the short term (behaviourally) and by modifying their coats and adjusting their metabolic rates in the longer term (acclimatisation). Evaporative heat loss in cattle is primarily from sweating, with some respiratory contribution, and is the primary mechanism for dissipating excess heat when environmental temperatures exceed skin temperature (~36°C). Cattle tend to be better adapted to cooler rather than hotter external conditions, with Bos indicus breeds more adapted to hotter conditions than Bos taurus. Management can minimise the risk of thermal stress by ensuring appropriate breeds of suitably acclimatised cattle, at appropriate stocking densities, fed appropriate diets (and water), and with access to suitable shelter and ventilation are better suited to their expected farm environment. 相似文献
86.
The production of M-protein antigen of Streptococcus equi was studied during in vitro growth in equine blood and in various media. Of 11 S equi strains studied, seven which had initially possessed 0.04 mg or less M-protein per 10 mg of streptococcal cell extract showed an increase in M-protein content after successive culture in heparinised horse blood. Maximum proliferation occurred in Todd-Hewitt (TH) medium with added 0.2 per cent w/v glucose when compared with TH medium alone or TH medium with 2 per cent w/v sucrose, starch, neopeptone or normal horse serum. The M-protein of these strains did not change after the addition of either neopeptone or normal horse serum to TH medium but declined with the addition of sugars. In experiments involving phagocytosis of S equi by equine polymorphs, the percentage of polymorphs which engulfed cocci was higher with a capsule-deficient strain (69.0 +/- 11.6 per cent) than with five typical encapsulated strains (21.1 +/- 7.0 per cent to 30.9 +/- 13.3 per cent). Phagocytosis of five typical strains was greater after growth in a trypsin-containing medium than in medium devoid of trypsin. Trypsin-grown cells took longer to kill mice than did normal cells. It was concluded that M-protein was one of the factors involved in the virulence of S equi. 相似文献
87.
Dichlorvos was applied as spray at 1 and 2% concentrations daily for a period of 28 and 21 consecutive days, respectively to buffalo calves. Animals sprayed with 1% dichlorvos displayed mild to moderate clinical signs of toxicosis during the 4th week of exposure. The higher concentration (2%) produced clinical signs of poisoning after 12-16 applications, and was lethal to one of three animals. Daily spraying of dichlorvos at both concentrations inactivated erythrocyte cholinesterase (ChE) (15-21%), plasma ChE (17-20%) and serum carboxylesterase (5-10%) within 3 days. The extent of inhibition of esterases was increased with repeated treatment and maximal inhibition of erythrocyte ChE (80-89%), plasma ChE (81-91%) and serum carboxylesterase (33-54%) with 1 and 2% concentrations was observed on the 28th and 21st day after start of application, respectively. In surviving animals, blood esterases remained inactivated to the extent of 14-65% on the 14th day after the termination of treatment. Dichlorvos at both concentrations significantly (P less than 0.01) elevated the serum levels of aspartate aminotransferase, alanine aminotransferase, acid phosphatase and alkaline phosphatase. The activities of these enzymes in surviving animals recovered to control values within 14 days after the final application of dichlorvos. 相似文献
88.
89.
The activity of the enzyme adenosine triphosphatase was measured in liver, testis and foetal fluids. The activity was maximum in the foetal liver and minimum in adult liver. On the other hand the activity in adult goat testis was higher than foetal goat testis. 相似文献
90.
Prothrombin time and activated partial thromboplastin time using a point‐of‐care analyser (Abaxis VSpro®) in Bennett's wallabies (Macropus rufogriseus) 下载免费PDF全文
BN Nevitt SK Chinnadurai MK Watson JN Langan MJ Adkesson 《Australian veterinary journal》2016,94(10):384-386
There are few reports of coagulation times in marsupial species. Blood samples collected from 14 Bennett's wallabies (Macropus rufogriseus) under anaesthesia during routine health assessments were analysed for prothrombin time (PT) and activated partial thromboplastin time (aPTT) using a point‐of‐care analyser (POC) (Abaxis VSPro®). The wallabies had an aPTT mean of 78.09 s and median of 78.1 s. The PT for all wallabies was greater than 35 s, exceeding the longest time measured on the POC. Although PT was significantly longer, aPTT was similar to the manufacturer's domestic canine reference range. 相似文献