全文获取类型
收费全文 | 1873篇 |
免费 | 95篇 |
专业分类
林业 | 158篇 |
农学 | 82篇 |
基础科学 | 9篇 |
590篇 | |
综合类 | 85篇 |
农作物 | 103篇 |
水产渔业 | 152篇 |
畜牧兽医 | 554篇 |
园艺 | 33篇 |
植物保护 | 202篇 |
出版年
2024年 | 1篇 |
2023年 | 24篇 |
2022年 | 38篇 |
2021年 | 59篇 |
2020年 | 75篇 |
2019年 | 77篇 |
2018年 | 68篇 |
2017年 | 78篇 |
2016年 | 72篇 |
2015年 | 60篇 |
2014年 | 83篇 |
2013年 | 147篇 |
2012年 | 130篇 |
2011年 | 173篇 |
2010年 | 88篇 |
2009年 | 87篇 |
2008年 | 127篇 |
2007年 | 112篇 |
2006年 | 98篇 |
2005年 | 80篇 |
2004年 | 68篇 |
2003年 | 57篇 |
2002年 | 60篇 |
2001年 | 12篇 |
2000年 | 17篇 |
1999年 | 15篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1968条查询结果,搜索用时 0 毫秒
11.
12.
Objective To compare intraocular pressure (IOP) measurements made on healthy adult rabbits without the effect of tranquilizers using the new applanation tonometer, Tono‐Pen Avia®, and the rebound tonometer Tonovet®. Methods Intraocular pressure was measured throughout the day (6:00, 9:00, 12:00, 15:00, and 18:00 h) in 38 adult New Zealand White rabbits (76 eyes). The animals were 20 males and 18 females, with a mean weight of 3.5 kg and an average age of 6 months. A complete ocular exam (including Schirmer tear test, fluorescein staining, slit‐lamp biomicroscopy, and direct ophthalmoscopy) was performed on all animals at the beginning of the trial. Rebound tonometry was performed, and after 10 min, anesthetic drops were instilled and applanation tonometry was carried out. IOP values obtained using the two techniques were analyzed statistically. Results The mean IOP was 9.51 ± 2.62 mmHg with Tonovet®, and 15.44 ± 2.16 mmHg with the Tono‐Pen Avia®. Significant differences between measurements with the two tonometers were observed (P < 0.001). The linear regression equation describing the relationship between the two tonometers was y = 0.4923x + 10.754 (y = Tonovet® and x = Tono‐Pen Avia®). High IOPs were recorded in the early measurements (6:00), but the average IOPs from both devices were statistically similar throughout the day (P = 0.086). The correlation coefficient was r2 = 0.357. No significant difference in IOP regarding gender was observed. Conclusion The Tono‐Pen Avia® recorded higher levels of IOP compared with the Tonovet®. Early in the day, the IOP of rabbits was higher than later in the day, regardless of the tonometer used. 相似文献
13.
14.
Capelli G Nardelli S di Regalbono AF Scala A Pietrobelli M 《Veterinary parasitology》2004,123(3-4):143-148
Risk factors associated with Neospora caninum seroprevalence in north-eastern Italy in healthy dogs were assessed. Antibodies to N. caninum were found in 10.9% of 707 kennel and owned dogs by a commercial competitive ELISA (VMRD Inc.). All dogs were negative for Leishmania infantum by indirect fluorescent antibody test indicating no cross reactivity or association between the two protozoa in this area. Seroprevalence association with breed and age of dogs and other factors are discussed. 相似文献
15.
Diego A. Galarza Antonio López-Sebastián Julián Santiago-Moreno 《Reproduction in domestic animals》2020,55(7):805-813
This study examines the effect of L-carnitine (LC) on chilled ram semen stored for up to 96 hr. Semen samples were collected, placed in a skimmed milk + 6% egg yolk extender, pooled, aliquoted and diluted with the same extender supplemented with different LC concentration: 0 (control), 1 mM (LC1), 2.5 mM (LC2.5), 5 mM (LC5), 7.5 mM (LC7.5) or10 mM (LC10). Sperm kinetics and membranes (plasma, acrosome and mitochondrial) were examined using the CASA system and triple fluorescence staining (PI/ PNA-FITC/Mitotracker). The progressive motility was greater (p < .05) with LC7.5 treatment than the control sperm at 96 hr. The curvilinear velocity (p < .01) and the percentage of sperm with intact membranes (plasma/acrosome/mitochondria) (p < .01) were greater with all LC treatments than the control group at all times. Straight line velocity was greater (p < .01) with LC5 and LC7.5 treatments than the control group after 48 hr. The LC5 group also returned lower ALH values (p < .05) than these seen for the control groups after 48 hr. The fertilizing capacity of LC5 samples stored at 15°C for 2 hr (LC5-15°C-2h) and at 5°C for 24 hr (LC5-5°C-24h) was tested in three ewe groups via cervical fixed-time artificial insemination. In two groups, the fertilizing capacity of the LC5-5°C-24h was reduced (p < .001). In the remaining group, however, no significant difference was seen between the LC5-15°C-2h and LC5-5°C-24h sperm in this respect (pregnancy rates 52.4% versus 42.8%; p > .05). Overall, the present results suggest that supplementing skimmed milk–egg yolk-based extenders with LC has a positive effect on chilled sperm variables and fertilizing capacity. 相似文献
16.
Correa Mdo A Aguiar AJ Neto FJ Mendes Gda M Steagall PV Lima AF 《American journal of veterinary research》2007,68(9):932-940
OBJECTIVE: To evaluate the effects of 2 remifentanil infusion regimens on cardiovascular function and responses to nociceptive stimulation in propofol-anesthetized cats. ANIMALS: 8 adult cats. PROCEDURES: On 2 occasions, cats received acepromazine followed by propofol (6 mg/kg then 0.3 mg/kg/min, i.v.) and a constant rate infusion (CRI) of remifentanil (0.2 or 0.3 microg/kg/ min, i.v.) for 90 minutes and underwent mechanical ventilation (phase I). After recording physiologic variables, an electrical stimulus (50 V; 50 Hz; 10 milliseconds) was applied to a forelimb to assess motor responses to nociceptive stimulation. After an interval (> or = 10 days), the same cats were anesthetized via administration of acepromazine and a similar infusion regimen of propofol; the remifentanil infusion rate adjustments that were required to inhibit cardiovascular responses to ovariohysterectomy were recorded (phase II). RESULTS: In phase I, heart rate and arterial pressure did not differ between remifentanil-treated groups. From 30 to 90 minutes, cats receiving 0.3 microg of remifentanil/kg/min had no response to noxious stimulation. Purposeful movement was detected more frequently in cats receiving 0.2 microg of remifentanil/kg/min. In phase II, the highest dosage (mean +/- SEM) of remifentanil that prevented cardiovascular responses was 0.23 +/- 0.01 microg/kg/min. For all experiments, mean time from infusion cessation until standing ranged from 115 to 140 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Although the lower infusion rate of remifentanil allowed ovariohysterectomy to be performed, a CRI of 0.3 microg/kg/min was necessary to prevent motor response to electrical stimulation in propofol-anesthetized cats. Recovery from anesthesia was prolonged with this technique. 相似文献
17.
Andrade MA Siles-Lucas M López-Abán J Nogal-Ruiz JJ Pérez-Arellano JL Martínez-Fernández AR Muro A 《Veterinary parasitology》2007,143(1):86-90
Trichinellosis is a cosmopolitan zoonotic disease affecting a wide variety of animals, including man. Non-encapsulated and encapsulated species diverge with respect to their developmental strategies. Little is known at the molecular level about parasite-derived mediators responsible for host muscle cell transformation occurring during trichinellosis. In this context, host-parasite relationships in Trichinella-infected animals could be related to different host-immune and cell mediators, e.g. nitric oxide (NO). Here, we investigate the stimulatory/inhibitory role of L1 antigens from four encapsulated (T. spiralis, T. britovi, T. nelsoni and T. nativa) and one non-encapsulated (T. pseudospiralis) Trichinella species on NO production from rat macrophages in vitro. Our results demonstrate that encapsulated and non-encapsulated Trichinella species differ in their capacity to stimulate the secretion of NO from host macrophages. Biological significance of these differences should be further assessed in the available experimental models. 相似文献
18.
Khobondo Joel Onyango Kingori Anthony Macharia Manhique Antonio 《Tropical animal health and production》2019,51(8):2213-2218
Tropical Animal Health and Production - The potential of using Prosopis juliflora pods was evaluated as a partial replacement of energy source layer’s diets. The main objective of the... 相似文献
19.
Claudio Bussadori DVM DECVIM Oriol Domenech DVM Antonio Longo DVM Danitza Pradelli DVM Roberto Bussadori DVM 《Journal of Veterinary Cardiology》2002,4(2)
A 6-months old female German shepherd dog was referred for management of congenital heart disease. A diagnosis of pulmonic stenosis (PS) and patent ductus arteriosus (PDA) was confirmed by Doppler echocardiography and cardiac catheterisation. The conditions were treated during a single cardiac catheterisation procedure using percutaneous techniques. Gianturco coil embolisation was used to close the PDA, and the PS was relieved using a balloon valvuloplasty technique. 相似文献
20.
Riondato F D'Angelo A Miniscalco B Bellino C Guglielmino R 《Veterinary journal (London, England : 1997)》2008,175(3):364-368
The effect of transportation on peripheral blood lymphocyte subsets in 24 calves was investigated by flow cytometry. Blood was collected before departure, on arrival, at 24h and 1 week after arrival. Highest leucocyte and neutrophil counts, associated with increased concentrations of cortisol and catecholamines, indicated that stress was maximal upon arrival. At this time, a decrease in the percentages of all T lymphocyte subsets was evident, while they did not decrease as absolute counts. The proportion of CD21(+) cells did not change, indicating that the relative reduction of T lymphocyte subsets was not related to an increase in B lymphocytes. These variations may be due to the increase of a natural killer (NK) cell subset. NK cell expansion, together with increasing lymphocyte count and increasing major histocompatibility complex class II expression, may indicate stress-induced stimulation of the immune system. 相似文献