全文获取类型
收费全文 | 232篇 |
免费 | 5篇 |
专业分类
林业 | 13篇 |
农学 | 17篇 |
基础科学 | 9篇 |
64篇 | |
综合类 | 9篇 |
农作物 | 21篇 |
水产渔业 | 25篇 |
畜牧兽医 | 57篇 |
园艺 | 4篇 |
植物保护 | 18篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 12篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有237条查询结果,搜索用时 421 毫秒
31.
Cultivars with submergence tolerant quantitative trait locus (SUB1) greatly enhance submergence tolerance at vegetative stage. Whether such cultivar is better off or not at reproductive stage submergence is not known. Due to uncertainties in rainfall pattern and delayed monsoon, flooding at later stages corresponding to reproductive stage is very much common now. Therefore, the main goal of the present investigation is to work out the effect of submergence at reproductive stage on yield and yield attributes in three rice cultivars namely Swarna, Swarna-Sub1, and Baliadhan (a traditional rice cultivar showed similar reaction to SUB1). The present study envisages that submergence at reproductive stage greatly decreased the grain yield even though there was no mortality of plants. Yield reduction was greater at flowering stage followed by booting and panicle initiation stage. Swarna-Sub1 performed significantly better compared to Swarna when submergence was given at panicle initiation stage. Swarna-Sub1 and Baliadhan both maintained greater quantities of carbohydrate and total dehydrogenase activity yet the yield reduction was greater in Swarna-Sub1 compared to Baliadhan due to greater chalf formation in the former. The cultivar with SUB1 is quite better off at reproductive stage submergence. Baliadhan is superior to Swarna-Sub1. 相似文献
32.
Mukesh Bhakat Tushar K. Mohanty Ashok K. Gupta Virendra S. Raina Biswajit Brahma R. K. Mahapatra M. Sarkar 《Tropical animal health and production》2010,42(7):1363-1366
Effect of Foot and Mouth disease (FMD) vaccination was studied on semen quality parameters of 19 Karan Fries (KF) and eight
Murrah (MU) breeding bulls during the period 2002 to 2004 at Artificial Breeding Complex, NDRI, Karnal. A total of non-vaccinated
155 KF and 72 MU bulls' ejaculates were taken as control, while 169 KF and 51 MU bulls' ejaculates, collected after vaccination,
were used to study the effect of vaccination stress. The results showed that FMD vaccination had no significant (P > 0.05) effect on ejaculate volume and total volume per day of semen in both KF and MU bulls. Volume of semen increased slightly
during post-vaccination period in both the breeds. After FMD vaccination, there was significant (P < 0.01) decrease in mass activity (2.27 ± 0.06 vs. 1.67 ± 0.07 and 2.49 ± 0.09. vs. 1.75 ± 0.10, for KF and MU, respectively),
initial motility (56.89 ± 0.03% vs. 44.62 ± 0.02% and 62.26 ± 0.04% vs. 47.08 ± 0.05%, for KF and MU, respectively), sperm
concentration (754.19 ± 23.96 vs. 554.14 ± 22.95 × 106/ml and 848.61 ± 33.65 vs. 571.57 ± 39.99 × 106/ml, for KF and MU, respectively), and total sperm output per ejaculate (3,685.94 ± 158.40 vs. 2,781.54 ± 151.70 × 106 and 2,218.75 ± 133.14 vs. 1,582.84 ± 158.20 × 106, for KF and MU, respectively). Application of FMD vaccine had significantly (P < 0.05) adverse effect on most of the seminal attributes during post-vaccination in KF and MU buffalo bulls. So, the spermiograms
affected following vaccination suggest that in bovines, the semen collection and preservation should be suspended till normal
fertility of sperm is restored to avoid the failure of conception from artificial insemination using such semen. 相似文献
33.
Krishna Mohan Vijay Kumar Mihir Sarkar B. S. Prakash 《Tropical animal health and production》2010,42(1):21-26
The objective of this study were (1) to establish the duration of behavioral estrus signs and timing of ovulation in Murrah
buffaloes (n = 10) and (2) to determine relationship between behavioral estrus signs with change in plasma estrogen concentrations.
Estrus and its behavioral signs were detected at hourly intervals by visual observations, per recta examination of genitalia
and bull parading four times in a day for 30 minutes each. Among the behavioral signs of estrus, swollen vulva (80%) was the
best indicator of estrus followed by excitement (70%). Among the duration of behavioral estrus signs the first and longest
duration of estrus signs was swollen vulva which was seen upto 19.8 ± 0.8 h after onset of estrus. The mean total duration
of estrus symptoms from appearance to disappearance of all the behavioral estrus symptoms was 23.5 ± 1.7 h. All the behavioral
estrus symptoms were observed during the period of estrogen surge. Endocrine profile during the periestrus period showed that
the mean peak concentrations of total estrogen 23.9 ± 3.9 pg/ml occurred at 8.8 ± 1.7 h after onset of estrus. The average
number of estrus symptoms observed per animal during onset of spontaneous estrus was 5.7. Ovulation occurred after 37.4 ± 1.7 h
after onset of estrus and 13.4 ± 1.0 h after end of total estrogen surge respectively. In conclusion, our results suggest
that all signs of behavioral estrus occurred during the preovulatory rise in estrogens. The first sign of estrus to be observed
was a swollen vulva and this symptom persisted the longest. 相似文献
34.
A. K. Sarkar Ekta Rai Syed Naseer Shah Sulochna Bouddha Y. K. Bansal S. A. Ansari 《New Forests》2010,40(3):323-334
Changes in nitrate reductase, i.e. NR (E.C. 1.7.1.1) activity, peroxidase (E.C. 1.11.1.14) activity, soluble sugars and phenols were monitored at various time intervals from day 0 to 60 during in vitro adventitious shoot regeneration from leaflet explants of Albizia procera (Roxb.) Benth. The explants were incubated on semi-solid Murashige and Skoog medium supplemented with 2.6 g l?1 Phytagel®, 2.5% sucrose, 10 μM BAP, 1 μM NAA and 15 μM AgNO3. NR activity, soluble sugars and phenols exhibited initial sharp rise on around day 20 followed by steep decline on day 25, whereas peroxidase activity peaked on day 50, highlighting significance of early input of nitrogen and energy and late emergence of lignification process for cellular differentiation and organization into adventitious shoot primordia. Morpho-anatomical changes in leaflets at various stages of in vitro adventitious shoot formation also followed the endogenous biochemical pattern. 相似文献
35.
Binoy Sarkar Ravi Naidu Mohammad Mahmudur Rahman Mallavarapu Megharaj Yunfei Xi 《Journal of Soils and Sediments》2012,12(5):704-712
Purpose
Naturally occurring layer silicate clay minerals can be value added by modifying their surface properties to enhance their efficacy in the remediation of environmental contaminants. Silicate clay minerals modified by the introduction of organic molecules into the mineral structure are known as organoclays and show much promise for environmental remediation applications. The present study assesses the extent of decrease in bioavailable and bioaccessible arsenic (As) via enhanced adsorption by soil treated with organoclays. 相似文献36.
Kumar V Kumar P Mohan K Sarkar M Suresh KP Chauhan MS Prakash BS 《Tropical animal health and production》2011,43(3):669-674
The objective of this study was to elucidate the changes in circulating levels of plasma interleukin-8 (IL-8) during peripartum
period in Murrah buffaloes (Bubalus bubalis). IL-8 was estimated in blood plasma of healthy peripartum Murrah buffaloes (n = 6) on days ±30, ±15, ±5, ±3, ±1 and 0 pre- and postpartum with respect to the day of parturition (day 0) in each of the
two different seasons (hot–humid and spring). The mean microclimate Temperature–Humidity Index (THI) during spring season
was significantly lower (p < 0.01) than the corresponding THI in hot–humid season. In both the seasons, plasma IL-8 remained lower in prepartum period
(≤46.56 ± 14.08 pg/ml during spring and ≤ 73.18 ± 18.56 pg/ml during hot–humid season) than in the postpartum period (≥51.41 ± 13.82 pg/ml
during spring and ≥ 84.13 ± 16.97 pg/ml in hot humid season). During spring, the IL-8 levels were significantly higher (P < 0.05) on days +5 and +15 postpartum in comparison to the IL-8 levels on days −30, −5, and −3 prepartum. During hot–humid
season, IL-8 level was significantly higher (P < 0.05) on day +30 as compared to the IL-8 levels on days −30 and −5 prepartum. The correlation between IL-8 and mean microclimate
THI was significant (r = 0.25, P < 0.01). From the results, it is concluded that peripartum period in buffaloes is associated with an inflammatory response
leading to significantly higher plasma IL-8 during parturition and postpartum period than in the pre-partum period. 相似文献
37.
This paper elaborates, analyzes, and partly defends the normative and empirical foundations of a “social ecology” model for natural habitat and resource management. This model treats human societies as being irreducibly integrated with the natural systems in which they are embedded. It argues that any concept of biodiversity necessarily embodies cultural values for it to be operationalized for conservation decisions. It accepts the legitimacy of tradeoffs between biodiversity conservation and other values including human resource development. It prioritizes local control of decisions in regions which are often targeted by Northern conservationists: areas of the South, where cultural choices have led to the persistence of high biodiversity. This model is used to analyze an ongoing dispute over biodiversity conservation and natural resource control in Perú: the conflict over Kandozi territory in the Abanico del Pastaza. What the Kandozi want is more than just a rejection of what has been criticized as the national park/fortress model of conservation. It consists of an assertion of local institutionalized control over traditional lands which goes well beyond the purview of the usual alternative of the fortress model: the biosphere reserve model of external and internal joint control of natural resources. To the remarkable extent that Kandozi resource management practices have succeeded in maintaining biotic richness and variety in spite of multiple encroachments, the empirical evidence demands that today’s conservationists pay adequate attention to these practices and the social institutions in which they are embedded. But, beyond such prudential concerns, the social ecology model of habitat conservation accepts the normative claims that resident communities should have control over their lands and livelihoods and that they should be allowed to maintain their habitats as cultural landscapes of their choice. 相似文献
38.
Suprakash Saha Monidipta Saha Amit Ranjan Saha Sabyasachi Mitra Surja Kumar Sarkar Ashesh Kumar Ghorai 《Journal of plant nutrition》2013,36(8):1191-1200
The interactive effect of potassium (K) and sulfur (S) fertilization on productivity and mineral nutrition of sunnhemp (Crotalaria juncea L.) was evaluated in a field experiment during 2008 and 2009 cropping seasons at Uttar Pradesh, India. Potassium and sulfur fertilizers increased fiber yield and nutrient uptake of sunnhemp. It was observed that an application of K and S at 40 kg ha?1 each significantly increased the total dry matter, fiber yield, and nutrient uptake of sunnhemp. The crop yield response to the added S was greater than for K and the nutrient use efficiency was also higher at lower levels of fertilizer addition. The increased levels of K and S improved the number of nodules and crude protein content of sunnhemp leaves. 相似文献
39.
40.