首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   263篇
  免费   20篇
林业   19篇
农学   10篇
基础科学   1篇
  31篇
综合类   13篇
农作物   7篇
水产渔业   44篇
畜牧兽医   146篇
园艺   1篇
植物保护   11篇
  2022年   9篇
  2021年   12篇
  2020年   8篇
  2019年   5篇
  2018年   1篇
  2017年   11篇
  2016年   13篇
  2015年   18篇
  2014年   10篇
  2013年   20篇
  2012年   9篇
  2011年   17篇
  2010年   11篇
  2009年   15篇
  2008年   12篇
  2007年   12篇
  2006年   15篇
  2005年   21篇
  2004年   17篇
  2003年   19篇
  2002年   13篇
  2001年   3篇
  2000年   4篇
  1999年   2篇
  1998年   1篇
  1993年   1篇
  1986年   2篇
  1963年   1篇
  1953年   1篇
排序方式: 共有283条查询结果,搜索用时 15 毫秒
231.
The accurate identification of mastitis‐causing bacteria assists in effective management by both dairy farmers and veterinarians and can be used to implement the selective use of antimicrobials for treatment. The purpose of this study was to evaluate the ability of our developed anti–ribosomal protein-L7/L12 antibody–coated immunochromatographic strip (ICS) test to detect coliforms in milk by comparing the results with the bacteriological culture method. We investigated the performance of the ICS test as compared with the bacteriological culture method using 308 milk samples from clinical bovine mastitis. First, to determine the optimal ICS test cutoff point for detecting coliform mastitis, we developed a receiver-operating characteristic curve. The result showed that the cutoff point was at 0.5 of our index. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of the ICS test were 81.3%, 84.8%, 69.2%, and 91.54%, respectively. As the clinical signs increased in severity, the F-measure, a weighted harmonic mean of the sensitivity and overall PPV performance, increased. Because it is especially important to treat clinical mastitis appropriately in the early stages of detection, the ICS test, which can be used by both dairy farmers and veterinarians on dairy farms, is considered to be a useful tool for detecting coliform mastitis, which often presents with severe signs.  相似文献   
232.
Shortage of organic matter hinders agricultural production in the Sahel, and this lack of enough organic matter is more severe for peri-urban horticulture, which depends heavily on it. Alternative sources of organic matter that offer new options for peri-urban horticulture can help reduce the potential for conflict over finite resources between traditional crop production and peri-urban horticulture. Both agronomic and economic evaluations of an organic amendment called heated sewage sludge (HSS) were conducted in the research station of International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)-Niamey, Niger, West Africa. For this study, HSS, a material imported from Japan, applied at a dosage application equivalent to 20.0 kg 100 m−2 on lettuce fields led to production levels as high as those of conventional methods, and the yield became even higher than those of conventional methods when the dosage was increased to 50.0 kg 100 m−2 and 100.0 kg 100 m−2. Even though HSS was imported, its benefits outweighed its cost, as evidenced by the positive net returns. Since profitability in peri-urban horticulture is much higher than that of traditional crop production, the results of this study imply that if adopted, the use of HSS can lead to increased availability of organic matter for traditional cropping systems.  相似文献   
233.
ABSTRACT:   In this study, we developed a new automatic system, comprised of a radio frequency identification (RFID) system and global positioning system (GPS), for monitoring fishing effort, and effectiveness of effort, in fisheries using many pieces of fishing gear, such as hooks of longlines. The outline of this system is as follows. A single RFID tag with an identification (ID) number is attached to each piece of fishing gear. The RFID tag on the fishing gear passes the antenna of the RFID reader before being shot into the sea and after being hauled up from the sea. Data on the time and geographic location are measured by the GPS and recorded along with the ID number in a personal computer (PC). When a fish is caught, it is brought close to the fish-sorting table. Then, the second antenna of the RFID reader set at the side checks for a catch in the gear. The advantage of this system is that the fishing operation data can be collected without interfering with the fishermen's usual work. The prototype of the system was tested at a conger-eel tube fishery in Tokyo Bay and was able to record data on the time, the location and the catch of individual conger-eel tubes successfully.  相似文献   
234.
To improve the nutritional quality of live foods and dry feeds ordinarily used for the seed production of amberjack Seriola dumerili, the nutrient contents of rotifers, Artemia nauplii and commercial feeds used in two larval production stations were evaluated. For comparison of the nutrient contents, artificially produced larvae, wild-caught juveniles and wild zooplankton samples were also analyzed. The proportions of 22∶6n-3 in the polar lipid of the cultured larvae increased by feeding the dry feeds. The taurine contents of the cultured larvae reflected the contents of their foods (rotifers<dry feed<Artemia nauplii). The taurine content and the proportion of 22∶6n-3 in Acartia spp. were higher than in foods fed to the larvae. These parameters in the wild juveniles were higher than the cultured ones. The A/E ratios [(each essential amino acid/total essential amino acids)×1000] of the total amino acids of the live foods and dry feeds were similar to those of the cultured larvae, except for the lower ratios of histidine, arginine, threonine and lysine in the live foods. The mucosal folds of the intestine of the cultured larvae did not show typical signs of dietary phospholipid deficiency. These results suggest that requirements of nutrients such as 22∶6n-3 and taurine should be determined for mass production of amberjack seeds.  相似文献   
235.
The aim of the present study was to evaluate the effects of continuous administration of linoleic acid or linolenic acid into the intra-uterine horn, ipsilateral to the corpus luteum, on the duration of the estrous cycle and plasma progesterone (P4) concentration. The effects of linoleic and linolenic acids on bovine uterine and luteal functions were also studied using a tissue culture system. Intra-uterine administration of linoleic or linolenic acid (5 mg/10 ml of each per day) in cows, between days 12 and 21, resulted in a prolonged estrous cycle compared to the average duration of the last one to three estrous cycles before administration in each group (P < 0.05). Moreover, plasma P4 concentration in cows treated with linoleic or linolenic acid was high between days 19 and 21 (linoleic acid), or on day 20 (linolenic acid), compared to that of the control cows (saline administration; P < 0.05 or lower). Both linoleic (500 µg/ml) and linolenic (5 and 500 µg/ml) acids stimulated prostaglandin (PG) E2 but inhibited PGF2α production by cultured endometrial tissue (P < 0.01), while P4 production by cultured luteal tissue was not affected. These findings suggest that both linoleic and linolenic acids support luteal P4 production by regulating endometrial PG production and, subsequently, prolonging the duration of the estrous cycle in cows.  相似文献   
236.
We previously reported that rhamnan sulfate (RS) purified from Monostroma nitidum significantly suppressed lipopolysaccharide (LPS)-induced inflammation in cultured human vascular endothelial cells. Here, we analyzed the effect of orally administered RS on LPS-induced damage to mouse organs and vascular endothelium. RS (1 mg) was orally administered daily to BALB/c mice, 50 μg of LPS was intraperitoneally administered on day 8, and Evans blue was injected into the tail vein 6 h later. After 30 min, LPS-treated mice showed pulmonary Evans blue leakage and elevated plasma levels of liver damage markers, whereas this reaction was suppressed in LPS + RS-treated mice. Immunohistochemical and Western blot analysis of mouse organs 24 h after LPS treatment showed significant neutrophil infiltration into the lung, liver, and jejunum tissues of LPS-treated mice and high expression levels of inflammation-related factors in these tissues. Expression levels of these factors were significantly suppressed in LPS + RS-treated mice. Analysis of lung glycocalyx showed a significant reduction in glycocalyx in LPS-treated mice but not in LPS + RS-treated mice. Levels of syndecan-4, one of the glycocalyx components, decreased in LPS-treated mice and increased in LPS + RS-treated mice. The current results suggest that orally administered RS protects organs and vascular endothelium from LPS-induced inflammation and maintains blood circulation.  相似文献   
237.
Fisheries Science - The marbled flounder Pseudopleuronectes yokohamae, a flatfish found in temperate coastal waters, is an important commercial species in the northwestern Pacific Ocean, but little...  相似文献   
238.
A 7-year-old female spayed Labrador Retriever was admitted to our hospital, because of cough with sputum. She was diagnosed as having canine eosinophilic pneumonia (CEP) based on blood eosinophilia, bronchial pattern and infiltrative shadow observed on thoracic radiography, bronchiolar obstruction and air-space consolidation predominantly affecting the right caudal lung lobe, as revealed by computed tomography (CT), predominant eosinophils in CT-guided fine needle aspiration and the clinical course. She exhibited a good response to steroid therapy, and the cough disappeared. The serum surfactant protein (SP)-A level increased with the aggravated symptom and decreased markedly with improvement compared with the C-reactive protein level and the number of eosinophils. We propose that serum SP-A level is a good biomarker in CEP.  相似文献   
239.
A rapid and efficient DNA extraction method was developed for detecting mastitis pathogens in milk. The first critical step involved cell wall disruption by bead-beating, as physical disruption using beads was more effective for DNA extraction from Gram-positive bacteria, such as Staphylococcus aureus, than enzymatic disruption using proteinase K. The second critical step involves the use of acetic acid and ammonium sulfate in the purification process, as these reagents effectively and efficiently remove the lipids and proteins in milk. Using these methods, DNA suitable for loop-mediated isothermal amplification was obtained within 30 min. Also, the rapid and sensitive detection of S. aureus in milk was possible at levels as low as 200 cfu/ml.  相似文献   
240.
The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to −2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号