全文获取类型
收费全文 | 488篇 |
免费 | 31篇 |
国内免费 | 1篇 |
专业分类
林业 | 40篇 |
农学 | 12篇 |
基础科学 | 2篇 |
154篇 | |
综合类 | 31篇 |
农作物 | 9篇 |
水产渔业 | 9篇 |
畜牧兽医 | 210篇 |
园艺 | 13篇 |
植物保护 | 40篇 |
出版年
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 16篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 11篇 |
2016年 | 16篇 |
2015年 | 15篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 37篇 |
2011年 | 40篇 |
2010年 | 24篇 |
2009年 | 12篇 |
2008年 | 31篇 |
2007年 | 31篇 |
2006年 | 33篇 |
2005年 | 38篇 |
2004年 | 25篇 |
2003年 | 16篇 |
2002年 | 24篇 |
2001年 | 15篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1931年 | 1篇 |
1908年 | 1篇 |
排序方式: 共有520条查询结果,搜索用时 62 毫秒
51.
Sabine Meinecke-Tillrnann H. Gips B. Meinecke A. Finkenberg 《Reproduction in domestic animals》1986,21(4):207-213
The changes in the plasma levels of oestrone sulphate and oestradiol-17β during the oestrous cycle, gestation and puerperium in the goat are described. The oestrone sulphate concentrations remained fairly constant (250–350 pg/ml) throughout the oestrous cycle until day 20 when a sharp increase of the oestrone sulphate plasma levels occurred in pregnant goats which became significantly different at day 38 of gestation from nonpregnant values. Oestradiol-17β plasma levels were significantly lower at days 17–20 in pregnant than in nonpregnant does. Oestrone sulphate and oestradiol-17β concentrations rose until the 12th week of gestation and then declined to about 50% of the former ranges of concentrations before rising again to high values at weeks 17–20 of gestation. Increasing plasma levels of oestrone sulphate and oestradiol-17β were determined during the last ten days preceding parturition. The concentrations of oestrone sulphate returned to basal levels by the 2nd—4th day post partum whereas oestradiol-17β values reached base values 24 hours after parturition. Both oestrogen concentrations remained constant during the puerperium until day 51 post partum . 相似文献
52.
It was the aim of this placebo-controlled study to evaluate the analgesic efficacy of the NASAID carprofen and the pure m-agonist levomthadone over a five-day postoperative evaluation period in dogs with fractures of the humerus or the femur (n = 30). Pain and sedation evaluation was carried out with a visual analogues system (VAS) and with the aid of a numerical estimation scale(NRS). The degree of lameness, the pain treshhold, the glucose and cortisol concentration curves as well as the respiration and heart rate and the systolic blood pressure were used as further pain indicators and to identify drug side effects. The levomethadon group displayed the lowest degree of pain on postoperative examination on the first day. On days 2 to 5, the carprofen group showed the lowest degree of pain in comparison to the placebo group. The levomethadon- and the carprofen group showed no statistically proven differences from day 2 on. Due to great variations in the pain scores and comparatively high median pain score especially on the first day of this study, the efficacy of all analgesics evaluated here must be regarded as insufficient in many cases. Only the parameter nociceptive pain treshhold showed a little, the degree of lameness, the glucose and cortisol levels showed no close correlation to the VAS and NRS pain scores and were therefore of little usefulness as postoperative pain indicators. No relevant clinical side effects caused by the used analgesics were detected in the kidney, the liver, the gastrointestinal tract and the circulatory system in this study. Rather, traumatically induced elevation of enzyme levels improves or normalised until the 5th day of the study. In addition, no negative effect on wound healing was noted, especially for carprofen. Therefore, the evaluated analgesics seems to be adequate for postoperative pain therapy also in fracture patients (trauma patients). However, the efficacy of all analgesics evaluated here must be regarded as insufficient in many cases. 相似文献
53.
Müller JM Feige K Kästner SB Naegeli H 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2005,19(3):348-349
A13-day-old Arabian Thoroughbred filly weighing 40 kg (88 1b) was presented to the University of Zurich Equine Clinic with a history of depression after deworming with moxidectin at a dose of 2 mg/kg (recommended dose 0.4 mg/kg body weight)a the day before admission. The foal was found recumbent 12 hours after drug administration and was in an unconscious state 6 hours later 相似文献
54.
Interferon-gamma (IFN-gamma) is a key cytokine in cell-mediated immunity. To measure IFN-gamma production of equine lymphocytes (eqIFN-gamma), we developed a quantitative ELISA. Monoclonal antibodies (mAb) were produced against bacterially derived eqIFN-gamma. The mAbs recognised recombinant and lymphocyte-derived eqIFN-gamma in ELISA, Western blotting, as well as flow cytometric and microscopic analysis. In contrast to bacterially derived material, mammalian and insect cell-derived eqIFN-gamma was biologically active but could be neutralised by one of the monoclonal antibodies. Unexpectedly, glycosylation seemed to be required for antiviral activity of eqIFN-gamma. 相似文献
55.
OBJECTIVE: To report the use of a nylon suture system (Canine Cranial Cruciate Ligament Repair System; Securos Inc Veterinary Orthopedics) as a prosthesis for equine laryngoplasty. STUDY DESIGN: Experimental and prospective clinical study. ANIMALS: Cadaver specimens (n = 5) and 7 horses with left laryngeal hemiplegia. METHODS: A commercially available monofilament nylon suture system was implanted as a laryngeal prosthesis. Arytenoid cartilage abduction was achieved with a tensioning device applied to the suture prosthesis during transnasal endoscopic observation. Suture fixation was achieved with crimping clamps and a crimping device. RESULTS: The nylon suture system was suitable as a laryngeal prosthesis for arytenoid cartilage abduction. The ratchet mechanism of the tensioning device facilitated abduction of the arytenoid cartilage and suture fixation was achieved by the crimped clamp without any loss of tension. Postoperatively, there was a slight loss of tension in 4 horses and complete loss of tension in 1 horse because of cartilage failure. After convalescence, none of the horses had abnormal respiratory noise, exercise intolerance or cough. CONCLUSIONS: A nylon suture system designed for canine cranial cruciate ligament repair was used successfully as a laryngeal prosthesis and facilitated control of the degree of arytenoid cartilage abduction during laryngoplasty. CLINICAL RELEVANCE: For improved control of the degree of arytenoid cartilage abduction during laryngoplasty, use of a nylon suture system with metal crimps should be considered. 相似文献
56.
57.
We report three cases of adult cats showing a prolapse of the gland of the third eyelid. Three different breeds were affected: Burmese, Persian and Domestic Short-haired. In all cases, the disorder occurred spontaneously, without any other ocular sign. Surgical replacement of the gland was performed using the Morgan pocket technique. Good esthetic results were obtained, and no recurrence occurred. 相似文献
58.
Adam M Contzen M Horlacher S Rau J 《Berliner und Münchener tier?rztliche Wochenschrift》2006,119(5-6):209-215
The identification of thermotolerant campylobacters in official food control in the state of Baden-Wuerttemberg has been traditionally performed using the cultural procedure as described in the ISO-Norm 10272:1995. Analysis thus took 5-6 days to complete. Additionally diagnostic problems caused by the accompanying flora as well as the resistance to nalidixic acid occured. Within the scope of this study these problems could be solved by introducing a filtration step for the reduction of the accompanying flora and by performing the indoxyl acetate-hydrolysis-test in addition to the antibiotic-resistance-test. Besides various PCR protocols for the identification of thermotolerant campylobacters from food were established as an alternative to the cultural procedure, providing reliable results within two days. Furthermore, infrared spectroscopy was tested for the identification of Campylobacter isolates. Using this technique and with the help of a suitable data base, bacterial pure cultures can be differentiated within 2 hours. Among others 356 samples of raw poultry meat were tested with the newly established procedures as well as with the classical cultural method, showing that 32% of the samples were Campylobacter spp. positive. 37% of these isolates were resistant against nalidixic acid. This indicates that the development of resistances in Campylobacter spp. in Germany follows the same trend described for other European countries. 相似文献
59.
60.
Ewers C Lübke-Becker A Bethe A Kiebling S Filter M Wieler LH 《Veterinary microbiology》2006,114(3-4):304-317
To learn more about the molecular biology of Pasteurella multocida 289 strains isolated from various clinically healthy and diseased hosts were examined for capsule biosynthesis genes (capA, B, D, E, and F) and 14 virulence associated genes by PCR and DNA-DNA-hybridization. As expected, capsule type A strains were highly adapted to bovines (92.3%) and poultry (85.7%) while we mainly found capA (34.9%)- and capD (58.1%)-positive strains in swine. A noticeable amount of capD-positive strains also originated from small ruminants (34.9%) and capF was detected in wild type strains from diseased cattle (2.2%) and cats (7.4%). None of the isolates harboured capE, while capB was exclusively found in all strains from buffaloes. Nearly all isolates showed a combination of genes encoding outer membrane proteins, colonization factors, iron aquisition factors and superoxid-dismutases without any clue for host specificity. In contrast, the transferrin binding protein encoding gene tbpA (31.5%) was limited to ruminant strains and only 37.0% of all P. multocida strains harboured pfhA, coding for a filamentous hemagglutinin, supposed to be a putative adhesion- und serum resistance factor. PfhA revealed a strong positive association to the outcome of disease in bovine hosts and in combination with toxA to that in swine. The dermonecrotoxin encoding toxA, present in 12.5% of all strains, was detected in isolates from swine, small ruminants, cattle, and poultry. A significant association to the disease status, however, was only existent in swine, although with 66.7% we found a notably high prevalence of the toxin gene among strains from small ruminants. The genes toxA, tbpA and pfhA as well as capsule biosynthesis genes are supposed to be important epidemiological marker genes for characterizing P. multocida field strains. 相似文献