全文获取类型
收费全文 | 3293篇 |
免费 | 308篇 |
国内免费 | 1篇 |
专业分类
林业 | 263篇 |
农学 | 135篇 |
基础科学 | 27篇 |
698篇 | |
综合类 | 131篇 |
农作物 | 209篇 |
水产渔业 | 479篇 |
畜牧兽医 | 1321篇 |
园艺 | 71篇 |
植物保护 | 268篇 |
出版年
2024年 | 7篇 |
2023年 | 45篇 |
2022年 | 60篇 |
2021年 | 141篇 |
2020年 | 144篇 |
2019年 | 174篇 |
2018年 | 172篇 |
2017年 | 184篇 |
2016年 | 184篇 |
2015年 | 136篇 |
2014年 | 177篇 |
2013年 | 186篇 |
2012年 | 251篇 |
2011年 | 264篇 |
2010年 | 135篇 |
2009年 | 126篇 |
2008年 | 202篇 |
2007年 | 165篇 |
2006年 | 156篇 |
2005年 | 114篇 |
2004年 | 113篇 |
2003年 | 95篇 |
2002年 | 84篇 |
2001年 | 56篇 |
2000年 | 46篇 |
1999年 | 26篇 |
1998年 | 6篇 |
1997年 | 19篇 |
1996年 | 5篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1985年 | 11篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1934年 | 2篇 |
1926年 | 1篇 |
1925年 | 1篇 |
1908年 | 1篇 |
排序方式: 共有3602条查询结果,搜索用时 703 毫秒
91.
1. Inclusion of raw faba bean (Vicia faba L., minor) in the diet of growing chickens was shown to affect the performance of the birds and to produce a significant increase in the relative weight of the pancreas. This was attributable to dietary trypsin inhibitors. 2. Trypsin inhibitors also produced degenerative changes in pancreatic acinar cells. These were observed by light and electron microscopy. 3. Progressive cytopathological changes were observed in the intestinal tract. The duodenum, jejunum and ileum were altered, with extensive erosion, shortening and atrophy of microvilli. 4. The results endorsed previous findings obtained using different legume seed lines (Phaseolus spp). Faba bean produced similar local reactions in the pancreas and the intestine. This may be caused by the presence of lectins in the seeds. 相似文献
92.
Mary Jo Burkhard Dennis J. Meyer Rod A. Rosychuk Shawn P. O'Neil Patricia C. Schultheiss 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(5):357-360
A monoclonal gammopathy composed of immunoglobulin G, with concurrent light-chain proteinuria and generalized lymph node plasmacytosis, was associated with chronic pyoderma in a dog. A uniform population of plasma cells was observed cytologically and histologically in multiple lymph node specimens. A diagnosis of monoclonal gammopathy of unknown significance was eventually made by exclusion of other known causes of monoclonal gammopathy, resolution after antibiotic therapy, and no evidence of lymphoproliferative disease after 11 months of follow-up and subsequent necropsy. This report expands the diagnostic considerations for monoclonal gammopathies in the dog. 相似文献
93.
The veterinary herd health and production control program for year-round calving herds, presented in this paper, comprises a basic system and a flexible system. The basic system is a uniform system of data recording, standard veterinary activities and problem detection for all farms. Record keeping by the farmer includes the updating of a farm diary and a fertility—health chart and the preparation of an examination list before each veterinary farm visit. Record keeping by the veterinarian comprises the updating of a general inventory and four index lists at each monthly visit. The index lists contain all relevant parameters or index figures needed to monitor the various aspects of the farm. These lists serve to detect unwanted situations or problems and to initiate problem analysis. The farm checklist, with time-related veterinary and agricultural attention points, is consulted at each farm visit. In this way, no aspect is omitted in the control program. Problem analysis is performed in the flexible system. This comprises subsystems adaptable to the specific demands on the farm at a given moment and with a given problem. It indicates to what extent action is needed to solve the problem. Agricultural activities must be coupled to veterinary activities in order to provide the farmer with optimal advice. The farm checklist can be considered as a link between the two disciplines: the veterinarian can enlist the agricultural officer at the right moment.The frame-work of the basic system is introduced with emphasis on record keeping by the farmer, veterinary farm visits and the farm checklist. 相似文献
94.
Summary Salmonellae were isolated from 17 out of 550 pigs and 3 out of 299 calves killed in the Uplands (Kenya) slaughterhouse but
none from 455 steers slaughtered at Nakuru.
Follow up visits to the farms of origin revealed no salmonella problems.
Resumen Se aisló salmonela de 17 de 550 cerdos y de 3 de 299 becerros sacrificados en el matadero de Uplands (Kenia). Pero no se encontró salmonela en 455 terneros sacrificados en otro matadero de Nakuru. Las visitas de inspección a los ranchos de donde provenian los animales no mostraron problema de salmonela.
Résumé Des Salmonelles ont été isolées chez 17 porcs sur un nombre total de 550 et chez 3 veaux sur un nombre total de 299, abattus à l'abattoir des Uplands (Kenya); aucune souche n'a été isolée à partir de 455 bouvillons abattus à Nakuru. A la suite de ces isolements, des visites effectuées dans les fermes d'origine ont montré qu'il n'existait aucun problème de Salmonellose.相似文献
95.
96.
Ortuño A Castellà J Marco I Ruiz M Lavín S 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2003,50(5):253-254
Ungulates are involved in the epidemiology of Borreliosis as maintenance hosts for vector tick species. We evaluated the prevalence of antibodies to Borrelia burgdorferi sensu lato in two different populations of southern chamois in Spain. Forty-six sera (40.4%) were positive at titres >/=1 : 64 using an indirect immunofluorescence assay (IFAT). 相似文献
97.
Chemical restraint of peccaries with tiletamine/zolazepam and xylazine or tiletamine/zolazepam and butorphanol 总被引:3,自引:0,他引:3
Selmi AL Mendes GM Figueiredo JP Guimarães FB Selmi GR Bernal FE McMannus C Paludo GR 《Veterinary anaesthesia and analgesia》2003,30(1):24-29
Objective To evaluate the use of a combination of tiletamine/zolazepam and xylazine (TZX) in collared and white‐lipped peccaries and to compare its efficacy as an anesthetic technique with that of tiletamine/zolazepam and butorphanol (TZB). Study design Prospective experimental trial. Animals Seven white‐lipped peccaries (Tayassu pecari) (four females and three males) and four collared peccaries (Tayasu tajacu) (two males and two females). Methods Animal immobilization was attempted with TZX and TZB (IM) on two different occasions. Heart and respiratory rates (HR, RR), rectal temperature (RT), sedation, muscle relaxation, posture, auditory response and analgesia were evaluated every 15 minutes during immobilization. Induction, anesthesia, standing and walking time were determined after drug administration. Results Doses for white‐lipped peccaries were 1.23 ± 0.26 mg kg?1 (mean ± SD) of TZ and 1.23 ± 0.26 mg kg?1 of X, and 1.46 ± 0.09 mg kg?1 of TZ and 0.14 ± 0.008 mg kg?1 of B; doses for collared peccaries were 1.51 ± 0.29 mg kg?1 of TZ and 1.51 ± 0.29 mg kg?1 of X and 1.68 ± 0.02 mg kg?1 of TZ and 0.17 ± 0.002 mg kg?1 of B. In white‐lipped peccaries, both drug combinations provided a smooth induction and good immobilization for more than an hour. Anesthesia and standing times were significantly longer in animals given TZB, whereas walking time was significantly longer in animals given TZX. A significant decrease in HR was observed with both treatments. Respiratory rate decreased significantly with TZX, but the rate remained higher than with TZB. Induction and recovery quality in white‐lipped peccaries was better with TZB than with TZX. Neither protocol provided adequate immobilization in collared peccaries. Conclusion and clinical relevance At the doses described, TZB is effective in providing a long period of immobilization, whereas TZX is adequate for short to medium immobilization in white‐lipped peccaries. Neither drug combination was effective in collared peccaries at the doses given. 相似文献
98.
del Río ML Gutiérrez B Gutiérrez CB Monter JL Rodríguez Ferri EF 《American journal of veterinary research》2003,64(9):1176-1180
OBJECTIVE: To determine duration and rates of recovery of Actinobacillus pleuropneumoniae and Haemophilus parasuis from 4 liquid media and 2 swab specimen transport systems and compare findings with those of Escherichia coli. SAMPLE POPULATION: One strain each of A pleuropneumoniae (biovar 1, serotype 1), H parasuis (serovar 5), and E coli (serotype O149:K91:H19). PROCEDURE: Strains were incubated in brain heart infusion broth supplemented with horse serum and other nutrients or in horse serum alone, with and without nicotinamide-adenine dinucleotide in both instances, for 150 days at 4 degrees C or room temperature (21 degrees C). Similarly, strains were tested in Stuart and Amies transport systems after storage at room temperature for 8 days. RESULTS: Colony counts greater than those of the initial inoculum were observed after incubation in horse serum for A pleuropneumoniae but not for H parasuis. Overall, incubation at 4 degrees C in the 4 liquid media resulted in longer recovery duration and higher rates than at room temperature. Culture of H parasuis resulted in lower recovery rates and shorter durations of recovery than culture of A pleuropneumoniae, except for culture in horse serum. Haemophilus parasuis survived longer than A pleuropneumoniae in the transport systems, and all organisms survived longer in the Amies system. CONCLUSIONS AND CLINICAL RELEVANCE: Survival of A pleuropneumoniae and H parasuis indicated that horse serum prolongs survivability, which may result in exposure of more animals during a prolonged period. The Amies system might be a good choice for collection of clinical samples from animals, especially for recovery of H parasuis. 相似文献
99.
In this investigation, we determined the prevalence of the Ornithobacerium rhinotracheale (ORT) infection in broilers and broiler breeders in southern Brazil. We also correlated the presence of antibodies in broilers with performance. Sera from 1550 broilers from 50 flocks were collected during the slaughter time in nine companies with federal veterinary inspection of the state of Rio Grande do Sul. Sera from 480 meat-type breeders of 40 flocks from 14 companies in southern Brazil were also analyzed by enzyme-linked immunosorbent assay, and the prevalence of antibodies was determined. The prevalence of ORT antibodies in broiler flocks was 63.83%, but in each individual flock only 6.52% of the birds were positive. The prevalence in broiler breeder flocks was 100.00%, and in each individual flock 94.62% of the birds were positive. There was a positive correlation between the presence of antibodies to ORT and decreased body weight in broilers. There was no significant correlation between presence of antibodies to ORT and age, lineage, efficiency index, feed conversion, and mortality. There was a positive correlation between the presence of respiratory signs and antibodies to ORT, although the reverse correlation was not significant. These results confirm that ORT is present and widespread in broilers and broiler breeders in southern Brazil. 相似文献
100.
Todhunter RJ Bertram JE Smith S Farese JP Williams AJ Manocchia A Erb HN Dykes NL Burton-Wurster NI Lust G 《Veterinary surgery : VS》2003,32(3):196-205
OBJECTIVE: To determine whether dorsal loading of the pelvis and type of chemical restraint affected the dorsolateral subluxation (DLS) score of dog hips. STYDY DESIGN: In vivo testing of diagnostic method. ANIMALS: Labrador retrievers, Greyhounds, and crosses between both breeds (n = 119 dogs). METHODS: Dorsal load was applied to the hips through a strap that was placed over the hips, and the peak vertical and steady-state vertical, ground-reaction forces exerted on the stifles were measured in the DLS position. The DLS score was measured with their hips under dorsal load and compared with the DLS score without load. For 24 dogs, the DLS score was measured both under chemical restraint (medetomidine) and under general anesthesia. Wilcoxon-signed rank test and paired t test was used to compare effects of dorsal load and restraint method on the left and right DLS hip score, and P <.05 was considered significant. RESULTS: Both stifles together accepted median 15% body weight in the vertical plane in the unloaded steady state. Loading the hips increased the steady-state, vertical ground-reaction force to 34% body weight. At 8 months of age, loading significantly decreased the DLS score from 65% +/- 11% (mean +/- SD) to 60% +/- 12% for left hips and 66% +/- 11% to 63% +/- 13% for right hips. The left hip DLS score was affected by load more consistently than the right hip. In general, loading the hips decreased the DLS score in all breeds by 4% to 6% except for the greyhounds, in which the DLS score was unchanged by dorsal loading. When grouped by their DLS scores, load significantly decreased DLS scores in dogs with unloaded scores greater than 55% (nondysplastic), whereas DLS scores of dogs with unloaded scores between 55% and 45% (dysplastic) and less than 45% did not change significantly with load. Unloaded scores did not change significantly when compared under sedation versus general anesthesia. However, load significantly decreased the DLS score under general anesthesia for the left hip but not for the right hip. CONCLUSIONS: Less than half of the vertical ground-reaction force normally exerted by the hindlegs of a standing dog was sufficient to induce hip subluxation in the DLS position. Although dorsal loading approximately doubled the steady-state, vertical ground-reaction force, the decrease in the DLS score under load was never greater than 6%. Furthermore, the DLS scores of dogs most likely to be dysplastic (based on DLS scores <45%) were not affected by load, whereas load slightly decreased DLS cores of dogs with DLS scores greater than 55%. CLINICAL RELEVANCE: External influences can change the DLS score significantly, but the magnitude of change is unlikely to be of clinical importance, making the method useful as a field screening test for both dysplastic and nondysplastic hips in young dogs. 相似文献