全文获取类型
收费全文 | 604篇 |
免费 | 14篇 |
专业分类
林业 | 26篇 |
农学 | 47篇 |
基础科学 | 4篇 |
67篇 | |
综合类 | 14篇 |
农作物 | 25篇 |
水产渔业 | 9篇 |
畜牧兽医 | 399篇 |
园艺 | 8篇 |
植物保护 | 19篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 14篇 |
2013年 | 79篇 |
2012年 | 18篇 |
2011年 | 21篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1976年 | 7篇 |
1968年 | 14篇 |
1966年 | 6篇 |
1964年 | 7篇 |
1963年 | 7篇 |
1960年 | 26篇 |
1959年 | 10篇 |
1957年 | 21篇 |
1956年 | 12篇 |
1955年 | 26篇 |
1954年 | 23篇 |
1944年 | 10篇 |
1943年 | 5篇 |
1942年 | 6篇 |
1941年 | 19篇 |
1940年 | 6篇 |
1927年 | 5篇 |
排序方式: 共有618条查询结果,搜索用时 15 毫秒
141.
142.
Biochemical analysis of uterine fluid for identification of indicators for subclinical endometritis in the water buffalo (Bubalus bubalis) 下载免费PDF全文
SC Gahlot S Kumar A Kumaresan S Vairamuthu KK Saraf L Sreela RK Baithalu SS Lathwal TK Mohanty 《Reproduction in domestic animals》2018,53(1):48-53
Alterations in biochemical constituents of uterine fluid have been suggested for diagnosis of subclinical uterine infection in the bovine. This study was undertaken to investigate whether uterine fluid biomolecules could act as tool for diagnosis of subclinical endometritis in the buffalo. Uterine fluid samples from normal (n = 22) and subclinical endometritis (n = 18; diagnosed based on uterine cytology)‐affected buffaloes were subjected to biochemical analysis. Among the different biochemical constituents estimated, urea, urea N, cholesterol, total bilirubin and alkaline phosphatase (ALP) concentrations were significantly (p < 0.05) higher in uterine fluid obtained from subclinical endometritis‐affected buffaloes. The extent of difference between normal and subclinical endometritis‐affected buffaloes was highest in ALP (69%) followed by cholesterol (55%), bilirubin (48%), urea (30%) and urea N (30%) concentrations. Receiver operating characteristic (ROC) analysis indicated that the likelihood ratio (LR) was 3.63 for urea, indicating that buffaloes having less than the threshold concentration (47.5 mg/dl) of urea in their uterine fluid were at 3.6 times more risk to be affected with SE. The LRs for urea N, cholesterol, ALP and bilirubin were 2.33, 2.54, 2.12 and 1.65, respectively. It was concluded that ALP, urea, urea N and cholesterol concentrations in uterine fluid may serve as an aid for diagnosing subclinical endometritis in the buffalo. 相似文献
143.
144.
145.
Water stress after flowering, one of the major factors limiting yields of pearl millet, affects both seed setting and grain filling and is a consequence of more/less water used prior to anthesis. However, whether genotypes have different sensitivities for seed setting and filling under drought, if exposed to similar stress intensity, is unclear. Experiments were conducted in two pairs of pearl millet genotypes, that is, PRLT2/89‐33 and H77/833‐2, 863B and 841B, contrasting for terminal drought tolerance, and two genotypes, ICMR 01046 and ICMR 01029 (IL‐QTLs), introgressed with a terminal drought tolerance QTL from PRLT2/89‐33 into H77/833‐2. Total seed weight, panicle number, 100‐seed weight, seed number and stover biomass were measured at different soil moistures and throughout grain filling. Sensitive H77/833‐2 had higher seed number and yield under well‐watered (WW) conditions than in PRLT2/89‐33 and IL‐QTLs. Upon increases in water stress intensity, H77/833‐2 suffered losses mostly in stover biomass (45 %) and seed number (60 %) at 0.3 FTSW whereas the biomass and seed number of PRLT2/89‐33 decreased little (20 % and 25 %). The 100‐seed weight of H77/833‐2 decreased only 20 % under stress. Tolerant 863B also maintained a higher seed number and biomass under water stress than 841B. Grain filling duration in PRLT2/89‐33 and IL‐QTLs was similar to that of H77/833‐2 under WW conditions but lasted longer than in H77833‐2 under water stress (WS). Similarly, seed growth of 863B was longer than 841B under WS. It is concluded that the higher seed yield of tolerant parents PRLT2/89‐33 and 863B, and of IL‐QTLs under WS was explained by the retention of a higher number of seeds than in sensitive lines, while the decrease in the 100‐seed weight was proportionally less than the decrease in seed number. Phenotype with lesser number and larger size of panicles and larger grain size, like genotypes PRLT2/89‐33 and 863B, withstood post‐anthesis water stress better. IL‐QTL inherited part of these characteristics, indicating a role for the terminal drought QTL in maintaining larger seed number and higher 100‐seed weight. The continuous stover biomass increase under WW in H77/833‐2, due to tillering, might indicate that tiller growth and grains are in competition for resources after anthesis, and this may relate to the relatively shorter grain‐filling period. 相似文献
146.
Subrata Kumar Shil Md. Mahiuddin Zahangir Bhajan Chandra Das Mohammad Mahbubur Rahman Saroj Kumar Yadav Md. Manzoorul Kibria AMAM Zonaed Siddiki 《Anatomia, histologia, embryologia》2023,52(2):180-189
Ganges River dolphins (Platanista gangetica spp. gangetica) are air-breathing, warm-blooded mammals endemic to the Ganges and Karnaphuli rivers of the Indian subcontinent. Nevertheless, very little basic histomorphological research has been conducted on this endangered species. Therefore, this study aimed to describe the morphological features of different organs of P. gangetica. Despite becoming aquatic animals, they showed similarities with terrestrial mammals, such as the pair of lungs and an apical bronchus in the respiratory system, which are pretty standard in ruminants and pigs. However, unlike the terrestrial animal, the tracheobronchial tree was stiffer due to circularly arranged anastomosing plates of the hyaline cartilaginous ring in the trachea, cartilaginous plates in the bronchiole, and thick alveolar septa. The digestive system showed a three-chambered mechanical and glandular stomach similar to the artiodactyles. However, the intestine showed smaller caecum like the monogastric mammal. The urogenital system showed lobulated kidneys, a urinary bladder, a fibroelastic penis with sigmoid flexure, and a long urethral process similar to some terrestrial ruminants. Considering the aquatic environment, all those modifications, unlike terrestrial mammals, are necessary for their adaptation. Thus, this research will broadly help our clinicians and conservationist to take further steps toward disease diagnosis and monitoring of marine health of this endangered species. 相似文献
147.
Oral feeding of male rats with the ethanolic leaf extract of Colebrookia oppositifolia at dose levels of 100 and 200 mg/kg for 8-10 weeks did not cause body weight loss, while the weights of testes and epididymides were significantly decreased. Seminal vesicles and ventral prostate showed a significant reduction at the higher dose only. Treated animals showed a notable depression of spermatogenesis. Following 100 and 200 mg/kg extract feeding, the preleptotene spermatocytes were decreased by 46.5 and 39.8%, the secondary spermatocytes by 13.4 and 12.7%, the step-19 spermatids by 36.6 and 35.2%, and the mature Leydig cells by 31.2 and 39.5%, respectively. At both dose levels, the seminiferous tubule diameter, Leydig cells nuclear area and cytoplasmic area, as well as the cross-sectional surface area of Sertoli cells, were significantly reduced (P<0.001) when compared to controls. Reduced sperm count and motility resulted in 100% negative fertility at 200 mg/kg dose level. A significant fall in the total protein and sialic acid content and acid phosphatase enzyme activity of the testes, epididymides, seminal vesicle and ventral prostate, as well as in the glycogen content of testes, was also observed at both dose levels in comparison with controls. 相似文献
148.
The stabilities of orange oil emulsions stabilized with various concentrations of two different types of corn fiber gum (CFG-1 and 2) isolated from coarse (pericarp) and fine (endosperm) fiber from corn wet milling have been studied. The emulsion stabilities in all these studies increased with increasing gum concentration up to a gum-to-oil ratio of 0.05, and after that it either levels off or changes very slightly. These results indicate that only 0.25% of CFG is required to make stable emulsion containing 5% orange oil under the experimental conditions used in this study. At this CFG concentration, CFG-2 from each fiber source was found to be a superior emulsifier relative to the corresponding CFG-1 from each source in a 10-day emulsion stability study at room temperature. The emulsion stability was also investigated by confocal laser scanning microscopy measurement, and it was found that CFG-1 and 2 from both coarse and fine fiber made stable emulsions with an average particle size of less than 1 mum for 10 days at room temperature. Sugar composition analysis of CFGs from both sources indicated that they were typical galactoglucuronoarabinoxylans containing mainly 55-59% xylose, 29-36% arabinose, and 4-6% galactose as neutral sugars and 3-5% glucuronic acid. Methylation analysis revealed a highly branched structure of all CFGs, in which only 16-25% of the 1--> 4-linked xylose residues were not substituted at O-2 and/or O-3. Arabinose is present both as a terminal residue and at branch points. 相似文献
149.
Z. Abraham Sangita Yadav M. Latha S. Mani S. K. Mishra 《Genetic Resources and Crop Evolution》2010,57(4):619-623
Madhuca longifolia (Koenig) J. F. Macbride is native to India. Seeds contain 20–50% oil (Mahua oil) and the seed cake is used as manure. Mahua
oil is used by rural communities for protection against storage pests. Almost all parts of this tree have medicinal properties.
Four explorations and collection missions was conducted during July–October 2007 in Tamil Nadu and the Union Territory of
Puducherry. This resulted in the collection of 55 accessions. Characterisation and analysis of 7 seed characters were done.
The existence of enormous variability in seed length, thickness and 100 seed weight indicates scope for utilization of these
accessions for selection of promising material for extraction of oil. Oil content of kernels has been evaluated. Kernel oil
ranged from 44.43 to 61.50%. Three accessions IC556617 with 61.50, IC556632 with 60.80 and IC556632 with 60.55% of kernel
oil are superior to the rest. Further collections in the site of these oil rich accessions are promising for more productive
Madhuca longifolia genetic resources. 相似文献
150.
The effects of Fasciola gigantica infection on bodyweight gain, dry matter intake, digestibility of nutrients and feed conversion efficiency in buffalo calves were investigated. Nine male buffalo calves of the Murrah breed, aged 12 to 15 months with a mean (se) bodyweight of 166 (12.5) kg, were randomly assigned to groups of five (group 1) and four (group 2). The animals in group 1 were given 1000 viable, mature metacercariae of F gigantica orally, while the animals in group 2 served as uninfected controls. They were stall fed on diets containing a concentrate mixture and ad libitum wheat straw and were maintained by standard management practices for a period of 165 days after infection. The average daily liveweight gain of the infected animals was 110.6 g, compared with 439.4 g in the uninfected controls, and was associated with the appearance and establishment of immature flukes in hepatic bile ducts. The feed conversion efficiency declined significantly (P<0.01) from 41 days after infection and was lowest at the end of the experiment. F gigantica infection did not influence the digestibility of the nutrients. The impaired feed conversion efficiency was mainly due to a reduction in dry matter intake due to inappetence. 相似文献