全文获取类型
收费全文 | 310篇 |
免费 | 29篇 |
国内免费 | 2篇 |
专业分类
林业 | 4篇 |
农学 | 11篇 |
基础科学 | 1篇 |
18篇 | |
综合类 | 30篇 |
农作物 | 6篇 |
畜牧兽医 | 264篇 |
园艺 | 2篇 |
植物保护 | 5篇 |
出版年
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 5篇 |
2014年 | 20篇 |
2013年 | 21篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 13篇 |
2009年 | 17篇 |
2008年 | 12篇 |
2007年 | 17篇 |
2006年 | 18篇 |
2005年 | 11篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 16篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1897年 | 1篇 |
排序方式: 共有341条查询结果,搜索用时 15 毫秒
101.
CM Balao da Silva C Ortega Ferrusola JM Gallardo Bolaños M Plaza Dávila P Martín‐Muñoz JM Morrell H Rodriguez Martínez FJ Peña 《Reproduction in domestic animals》2014,49(6):1021-1027
Flow cytometry is considered the only reliable method for the separation of X and Y chromosome bearing spermatozoa in equines. The MoFlo SX DP sorter is highly efficient, allowing the production of foals of the desired sex. However, to achieve acceptable pregnancy rates the currently used protocol requires working with fresh semen obtained close to, or at, the sorting facility. An alternative protocol was tested during two consecutive breeding seasons. Fresh stallion semen was cooled for 20 h, during which staining with Hoechst 33342 took place. On the following day, this sample was flow sorted and compared with spermatozoa from the same ejaculate that had been sexed on the previous day. All sperm parameters evaluated remained unchanged when fresh sorted and refrigerated sorted semen were compared. Pre‐sorting storage at 5°C did not alter sperm velocities nor kinetics, viability or membrane permeability, production of reactive oxygen species, mitochondrial membrane potential or DNA fragmentation index of the sorted sample. The findings open for the possibility of using semen from stallions housed far from the sorting facilities. Processed and stained sperm could be shipped refrigerated on the previous day, sorted and inseminated on the next day. 相似文献
102.
LA Gracia‐Calvo LJ Ezquerra M Martín‐Cuervo ME Durán H Tapio JM Gallardo FJ Peña C Ortega‐Ferrusola 《Reproduction in domestic animals》2014,49(6):1043-1048
Laparoscopic hernioplasty techniques have been developed in the recent years to avoid the recurrence of inguinal hernias and to spare the testicles for breeding purposes in stallions. However, there have been no previous comprehensive and systematic studies of the reproductive outcomes and prognoses for stallions after inguinal hernioplasty. Therefore, the objective of this study was to assess the possible effects of one of these techniques (standing laparoscopic peritoneal flap hernioplasty) on the sperm production and motility characteristics of six healthy stallions that received this procedure based on 1‐year follow‐ups. There were no significant differences in the measured sperm variables (assessments based on the DSO, MOT, PMOT, VSL, VCL and VAP) during 1‐year follow‐ups. 相似文献
103.
Y Yulnawati MC Abraham D Laskowski A Johannisson JM Morrell 《Reproduction in domestic animals》2014,49(6):954-956
The objective of this study was to evaluate bull sperm kinematics after centrifugation through a single layer of a colloid [Single Layer Centrifugation (SLC)]. Ejaculates from 20 bulls were extended and stored at 4–6°C for 24 h during transport to the laboratory for SLC through Androcoll‐B, followed by measurement of sperm kinematics in all samples. Total motility (86% and 88% for uncentrifuged and SLC samples, respectively) and progressive motility (84% for both the groups) were similar (p > 0.05). In contrast, straightness (STR) (0.65 vs 0.69), linearity (LIN) (0.32 vs 0.35) and beat cross frequency (BCF) (22.3 vs 23.6 Hz) were significantly higher in the SLC‐selected samples than in the uncentrifuged samples, whereas velocity of the average path (VAP) (95 vs 90 μm/s), curvilinear velocity (VCL) (192 vs 180 μm/s), amplitude of lateral head deviation (ALH) (7 μm vs 6.5 μm) and hypermotility (49% vs 38%) were significantly decreased. The kinematics of the samples with the poorest motility was improved most by SLC. In conclusion, even though SLC had no direct effect on total and progressive motility, it appeared to have a positive influence on several other kinematic parameters that may be important for fertilization after artificial insemination. 相似文献
104.
Croucher NJ Harris SR Fraser C Quail MA Burton J van der Linden M McGee L von Gottberg A Song JH Ko KS Pichon B Baker S Parry CM Lambertsen LM Shahinas D Pillai DR Mitchell TJ Dougan G Tomasz A Klugman KP Parkhill J Hanage WP Bentley SD 《Science (New York, N.Y.)》2011,331(6016):430-434
Epidemiological studies of the naturally transformable bacterial pathogen Streptococcus pneumoniae have previously been confounded by high rates of recombination. Sequencing 240 isolates of the PMEN1 (Spain(23F)-1) multidrug-resistant lineage enabled base substitutions to be distinguished from polymorphisms arising through horizontal sequence transfer. More than 700 recombinations were detected, with genes encoding major antigens frequently affected. Among these were 10 capsule-switching events, one of which accompanied a population shift as vaccine-escape serotype 19A isolates emerged in the USA after the introduction of the conjugate polysaccharide vaccine. The evolution of resistance to fluoroquinolones, rifampicin, and macrolides was observed to occur on multiple occasions. This study details how genomic plasticity within lineages of recombinogenic bacteria can permit adaptation to clinical interventions over remarkably short time scales. 相似文献
105.
S. D. Shaw L. G. Arroyo A. zur Linden C. Allen A. Giraldo N. D. Cohen 《Equine Veterinary Education》2021,33(12):e477-e481
A 4-month-old Thoroughbred filly presented with pyrexia, inappetence and diarrhoea. Abdominal ultrasonography revealed a multilobulated abdominal mass that was determined to be associated with the caecum using computed tomography. Computed tomography also identified mesenteric lymphadenopathy and a pulmonary mass in the left caudal lung lobe. Percutaneous aspiration of the abdominal mass yielded pure growth of Rhodococcus equi. The filly responded in a positive fashion to the administration of clarithromycin, rifampin and gallium maltolate. Follow-up computed tomography revealed complete resolution of the abdominal mass and lymphadenopathy. Extrapulmonary disorders associated with R. equi should be considered even when thoracic ultrasonography reveals no evidence of pulmonary pathology. Although intra-abdominal abscesses have a grave prognosis, successful treatment is possible. Gallium maltolate can be safely administered to foals and may improve patient outcomes. 相似文献
106.
Jan?SerroyenEmail author Geert?Molenberghs Marleen?Verhoye Vincent?Van?Meir Annemie?Van der?Linden 《Journal of Agricultural, Biological & Environmental Statistics》2005,10(2):170-183
We analyze data on the impact of testosterone on the dynamics of Mn2+ accumulation measured by magnetic resonance imaging in three songbird brain areas: the nucleus robustus arcopallii (RA),
area X, and the high vocal center (HVC). Birds with and without testosterone were included in the experiment, and repeated
measurements were available in both a preand post-drug administration period. We formulate a nonlinear modeling strategy,
allowing for the incorporation of (1) within-bird correlation, (2) the nonlinearity of the profiles, and (3) the effect of
treatment. For two of the outcomes (RA and area X), biological theory suggests a parametric form, but for HVC this is not
the case. Because the HVC outcome bears some resemblance with the two-compartment model known from pharmacokinetics, this
model was considered a sensible choice. We use a different model, based on fractional polynomials, as a sensitivity analysis
for the latter. All methods used provide good fits to the data, confirm results from previous, simple analyses undertaken
in the literature, but were able to detect additional effects of treatment that had so far gone undetected. The fractional
polynomial and two-compartment models provide similar substantive conclusions; the two together can be seen as a form of sensitivity
analysis. 相似文献
107.
Aubel NA Jaeger JR Drouillard JS Schlegel MD Pacheco LA Linden DR Bolte JW Higgins JJ Olson KC 《Journal of animal science》2011,89(11):3699-3706
The effects of mineral-supplement delivery system on patterns of supplement use by grazing beef cows were measured in 2 studies. Study 1 was conducted on 4 pastures grazed by pregnant, mature beef cows (BW = 562 ± 38 kg) from February to May. Study 2 was conducted on 4 pastures grazed by lactating beef cows (BW = 579 ± 54 kg) and their calves from May to September. Treatments were mineral delivered in salt-based, granular form (salty) or mineral provided in a low-protein, cooked, molasses-based block (sweet); both were fed ad libitum. The salty supplement was supplied to cattle via a covered mineral feeder; the sweet supplement was supplied via an open-topped barrel. Both salty and sweet supplements were deployed in each pasture. No additional salt was supplied to cattle. Forage use in the vicinity of each supplement-deployment site and the frequency and duration of herd visits to each supplement-deployment site were measured during four 14-d periods during study 1 and seven 14-d periods during study 2. Supplements were moved to new locations within pastures at the beginning of each period. Consumption of the sweet supplement was greater than salty during each data-collection period in study 1; however, relative differences in consumption diminished over time (treatment × time, P = 0.03). In study 2, sweet consumption was greater than salty in periods 1, 6, and 7 but was not different from salty during periods 2, 3, 4, and 5 (treatment × time, P < 0.01). Increased consumption of the sweet supplement in study 1 translated to greater frequency of herd visits to supplement-deployment sites compared with the salty sites (2.82 vs. 2.47 herd visits/d; P = 0.02) and longer herd visits to supplement-deployment sites compared with the salty sites (125.7 vs. 54.9 min/herd visit; P < 0.01). The frequency of herd visits to mineral feeding sites in study 2 was similar (P > 0.10) between treatments for periods 1 through 6; however, herds visited the sweet sites more often than salty during period 7 (P < 0.01). Herd visits to the sweet sites were longer than those to the salty sites in study 2 (83.8 vs. 51.4 min/herd visit; P < 0.01). Forage disappearance within 100 m of supplement-deployment sites was not influenced (P ≥ 0.54) by treatment in either study. Results were interpreted to suggest that the sweet supplement influenced the location of grazing cattle more strongly than the salty supplement and may be more effective for luring cattle into specific areas of pasture during the winter, spring, and early fall but not during summer. 相似文献
108.
Antibody responses following administration of a Cryptosporidium parvum rCP15/60 vaccine to pregnant cattle 总被引:1,自引:0,他引:1
Burton AJ Nydam DV Jones G Zambriski JA Linden TC Cox G Davis R Brown A Bowman DD 《Veterinary parasitology》2011,175(1-2):178-181
Cryptosporidium parvum is a zoonotic Apicomplexa-protozoan pathogen that causes gastroenteritis and diarrhea in mammals worldwide. Globally, C. parvum is ubiquitous on dairy operations and is the pathogen most commonly diagnosed in association with calf diarrhea. Here, we describe the antibody response in 20 pregnant cows to a recombinant C. parvum oocyst surface protein (rCP15/60) vaccine compared with 20 controls, and the antibody response in 19 calves fed the rCP15/60-immune colostrum from these vaccinated cows compared with 20 control calves. Cows vaccinated with rCP15/60 produced a significantly greater antibody response compared to controls (p<0.0001) and this response was strongly associated with the subsequent level of colostral antibody (r=0.82, p<0.0001). Calves fed rCP15/60-immune colostrum showed a dose-dependent absorption of antibody, also associated with colostral antibody levels (r=0.83, p<0.0001). Currently, drug therapy against cryptosporidiosis is limited making development of an effective vaccine attractive. This report describes the first stages in development of a C. parvum rCP15/60 vaccine designed to confer passive protection to calves against cryptosporidiosis. 相似文献
109.
W A Buurman P A Vegt G Groenewegen C J van der Linden G M Jeunhomme 《Veterinary immunology and immunopathology》1982,3(6):547-556
Isolation of canine peripheral blood mononuclear cells with a one step centrifugal separation procedure has not been very successful sofar. Significant contamination with polymorphonuclear cells has been reported. An analysis of the buoyant density of canine peripheral blood leukocytes on a self-generating Percoll gradient showed that the buoyant densities of polymorphonuclear cells and lymphocytes are so near that separation with high purity and yield is not possible with the use of a density gradient. Transient changes in buoyant density of polymorphonuclear cells have been observed. In such situations differences in buoyant density between cell types have been observed which permit separation of mononuclear cells from polymorphonuclear cells at a reasonable yield. 相似文献
110.
SUMMARY Subclinical nutritional myopathy was induced in 5-month-old sheep by feeding them a diet low in vitamin E and selenium. Subsequently clinical myopathy was induced by dosing with protected polyunsaturated fatty acids. Plasma activities of creatine kinase (CK), pyruvate kinase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase and aldolase, enzymes of muscle origin, all remained above their reference ranges in clinically affected sheep, but fluctuated widely. Similar fluctuations occurred in subclinically affected animals, resulting in some activities being within the reference ranges and some above, at different times. Plasma malondialdehyde, an indicator of lipid peroxidation, proved of no diagnostic value. Terminal plasma CK activities were significantly correlated with microscopic damage in the vastus lateralis (VL), but not the vastus intermedius (VI) or the tensor fascia lata (TFL) muscles. AST was the most highly correlated with damage in VI and VL. In two clinically affected sheep successfully treated with an oral dose of α-tocopherol actetate all enzymes decreased steadily to within their reference ranges, at rates probably related to their plasma half-lives. These results suggest that measurement of plasma CK activity would be useful in monitoring recovery of treated sheep. 相似文献