全文获取类型
收费全文 | 2906篇 |
免费 | 212篇 |
国内免费 | 4篇 |
专业分类
林业 | 136篇 |
农学 | 53篇 |
基础科学 | 10篇 |
340篇 | |
综合类 | 407篇 |
农作物 | 65篇 |
水产渔业 | 148篇 |
畜牧兽医 | 1712篇 |
园艺 | 71篇 |
植物保护 | 180篇 |
出版年
2023年 | 15篇 |
2022年 | 16篇 |
2021年 | 48篇 |
2020年 | 63篇 |
2019年 | 50篇 |
2018年 | 50篇 |
2017年 | 57篇 |
2016年 | 55篇 |
2015年 | 50篇 |
2014年 | 78篇 |
2013年 | 151篇 |
2012年 | 163篇 |
2011年 | 197篇 |
2010年 | 120篇 |
2009年 | 103篇 |
2008年 | 167篇 |
2007年 | 168篇 |
2006年 | 164篇 |
2005年 | 156篇 |
2004年 | 168篇 |
2003年 | 165篇 |
2002年 | 128篇 |
2001年 | 50篇 |
2000年 | 52篇 |
1999年 | 37篇 |
1998年 | 22篇 |
1997年 | 21篇 |
1996年 | 17篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 19篇 |
1992年 | 33篇 |
1991年 | 30篇 |
1990年 | 39篇 |
1989年 | 33篇 |
1988年 | 29篇 |
1987年 | 22篇 |
1985年 | 16篇 |
1984年 | 14篇 |
1983年 | 18篇 |
1979年 | 26篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1974年 | 16篇 |
1973年 | 14篇 |
1972年 | 14篇 |
1971年 | 14篇 |
1970年 | 14篇 |
1969年 | 14篇 |
1967年 | 13篇 |
排序方式: 共有3122条查询结果,搜索用时 15 毫秒
1.
Leslie Boerner Kathleen R Nevis Lynn S Hinckley E Scott Weber Salvatore Frasca 《Journal of veterinary diagnostic investigation》2004,16(2):145-149
On June 25, 2002, aquarium veterinarians treated a 5-year-old, male little blue penguin (Eudyptula minor) that was acutely recumbent and dull, with inappetence of 24-hour duration. The penguin died within 10 minutes of presentation despite emergency resuscitation efforts. Gross pathologic findings consisted of pulmonary congestion and intestinal hemorrhage. Histopathologic findings included necrosis of tips of intestinal villi, increased numbers of mononuclear cells in pulmonary interstitium and hepatic sinusoids, and gram-positive bacteria in systemic microvasculature. Transmission electron microscopic examination revealed short gram-positive bacilli located in lumina of glomerular capillaries and in cytoplasm of mononuclear phagocytic cells in the lung and liver. Erysipelothrix rhusiopathiae was recovered from the lung, liver, and intestine by bacteriologic culture. Amplicons from polymerase chain reaction (PCR) tests using Erysipelothrix genus-specific primers and total genomic DNA extracted from formalin-fixed, paraffin-embedded tissue sections of lung and intestine demonstrated 99% nucleotide sequence identity with 16S small-subunit ribosomal DNA of E. rhusiopathiae and E. tonsillarum. The source of infection was speculated to be fish in the diet; however, repeated attempts to detect Erysipelothrix spp. from the mucous layer of food fish using bacteriologic culture and PCR were unsuccessful. This is the first report of erysipelas in a captive aquatic bird. Details of the isolation of E. rhusiopathiae and the application of molecular testing to identify Erysipelothrix DNA in formalin-fixed, paraffin-embedded tissue sections are given. 相似文献
2.
Jenifer Chatfield Scott Citino Linda Munson Stanley Konopka 《Journal of zoo and wildlife medicine》2004,35(2):137-141
Historically, therapeutic monitoring for prescribed eradication treatment of Helicobacter in cheetahs (Acinonyx jubatus) with associated gastritis has been accomplished only through endoscopic biopsies. The 13C-urea breath test (UBT) can offer an alternative to repeated biopsies for therapeutic monitoring. Five male and five female cheetahs and one male Sumatran tiger (Panthera tigris) were studied. All were clinically healthy before and after this investigation. Breath samples of end-tidal expiration were taken before and after administration of a 13C-enriched urea solution through a gastroesophageal tube. Twenty-milliliter breath samples were taken at 10, 20, 30, and 40 min after administration of the urea solution. The results of the breath analysis were compared with the results of rapid urease testing, histopathologic examination, and impression smears of gastric biopsies taken at the time of the breath test. The sensitivity and specificity for the 13C-UBT in this investigation were 100%. and the positive predictive value and negative predictive value were both 100%. Although the 13C-UBT is a good noninvasive diagnostic tool for monitoring the presence of Helicobacter sp. in the gastric mucosa, endoscopy should still be used for initial diagnosis and grading of gastritis and for monitoring the progression of disease in cheetahs. The 13C-UBT is a valuable, simple, accurate, and sensitive tool for monitoring eradication of Helicobacter during therapy for clinical gastritis. 相似文献
3.
Kaiping Deng Steffen Uhlig Laura B. Goodman Hon S. Ip Mary Lea Killian Sarah M. Nemser Jodie Ulaszek Shannon Kiener Matthew Kmet Kirstin Frost Karina Hettwer Bertrand Colson Kapil Nichani Anja Schlierf Andriy Tkachenko Mothomang Mlalazi-Oyinloye Andrew Scott Ravinder Reddy Gregory H. Tyson 《Journal of veterinary diagnostic investigation》2022,34(5):825
The COVID-19 pandemic presents a continued public health challenge. Veterinary diagnostic laboratories in the United States use RT-rtPCR for animal testing, and many laboratories are certified for testing human samples; hence, ensuring that laboratories have sensitive and specific SARS-CoV2 testing methods is a critical component of the pandemic response. In 2020, the FDA Veterinary Laboratory Investigation and Response Network (Vet-LIRN) led an interlaboratory comparison (ILC1) to help laboratories evaluate their existing RT-rtPCR methods for detecting SARS-CoV2. All participating laboratories were able to detect the viral RNA spiked in buffer and PrimeStore molecular transport medium (MTM). With ILC2, Vet-LIRN extended ILC1 by evaluating analytical sensitivity and specificity of the methods used by participating laboratories to detect 3 SARS-CoV2 variants (B.1; B.1.1.7 [Alpha]; B.1.351 [Beta]) at various copy levels. We analyzed 57 sets of results from 45 laboratories qualitatively and quantitatively according to the principles of ISO 16140-2:2016. More than 95% of analysts detected the SARS-CoV2 RNA in MTM at ≥500 copies for all 3 variants. In addition, for nucleocapsid markers N1 and N2, 81% and 92% of the analysts detected ≤20 copies in the assays, respectively. The analytical specificity of the evaluated methods was >99%. Participating laboratories were able to assess their current method performance, identify possible limitations, and recognize method strengths as part of a continuous learning environment to support the critical need for the reliable diagnosis of COVID-19 in potentially infected animals and humans. 相似文献
4.
Ana M. Casas Carlota R. Gazulla Arantxa Monteagudo Carlos P. Cantalapiedra Marian Moralejo M. Pilar Gracia Francisco J. Ciudad William T.B. Thomas José L. Molina-Cano Scott Boden Bruno Contreras-Moreira Ernesto Igartua 《作物学报(英文版)》2021,(4):862-872
Response to vernalization and photoperiod are the main determinants controlling the time to flowering in temperate cereals. While the individual genes that dete... 相似文献
5.
氯的使用可有效减少家禽胴体和屠宰加工厂的细菌。但是,我们有必要对氯有一个更好的认识和管理。 相似文献
6.
Scott A Kramer Brooklyn K Wagner Ivelisse Robles Steve J Moeller Andrew S Bowman Justin D Kieffer Andria Gonalves Arruda Michael D Cressman Monique D Pairis-Garcia 《Journal of animal science》2021,99(3)
Euthanasia of mature swine is challenging. Temporal and behind-the-ear locations are two sites that have been identified as alternatives to the more commonly used frontal placement. In stage one, the effectiveness of two penetrating captive bolt gun styles (cylinder or pistol) was evaluated using frontal, temporal, and behind-the-ear placement in anesthetized mature swine (n = 36; weight: 267 ± 41 kg). For stage one, when evaluating treatment efficacy by sex, the cylinder-style equipment was 100% effective in achieving death when applied to all cranial locations (frontal, temporal, and behind-the-ear) for sows; however, the pistol-style equipment was only 100% effective when applied at the behind-the-ear location for sows. For boars, the cylinder-style equipment was 100% effective when applied to the frontal and behind-the-ear location, but the pistol-style equipment was not effective for any cranial location in boars. Therefore, the pistol–frontal, pistol–temporal, pistol–behind-the-ear, and cylinder–temporal were not included for boars, and pistol–frontal and pistol–temporal were not included for sows in stage two. In stage two, commercial, mixed-breed, mature swine (n = 42; weight: 292 +/− 56 kg) were randomly assigned to one of four treatments based on the inclusion criteria described in stage one. A three-point traumatic brain injury (TBI) score (0 = normal; 1 = some abnormalities; 2 = grossly abnormal, unrecognizable) was used to evaluate six neuroanatomical structures (cerebral cortex, cerebellum, hypothalamus, thalamus, pons, and brain stem), and the presence of hemorrhage was also noted. All treatments were 100% effective in stage two. A significant interaction between gun style and placement was determined on predicting total TBI as the cylinder style produced a higher total TBI score compared with the pistol type of the magnitude of +2.8 (P < 0.01). The cylinder style tended to produce a greater TBI score than the pistol in the temporal location (+1.2; P = 0.08). No difference was noted for TBI score behind-the-ear between the cylinder- and pistol-style gun (P > 0.05). TBI tended to be less in boars compared with sows (−0.6; P = 0.08). Hemorrhage was observed in frontal, parietal, occipital, and temporal lobes. This study demonstrated that the cylinder-style captive bolt gun more effectively resulted in brain trauma and death compared with a pistol-style gun and the behind-the-ear and temporal placement showed promise as an alternative placement site for euthanizing mature pigs on-farm. 相似文献
7.
Daniel J. Joffe Roxana Lelewski J. Scott Weese Jamie Mcgill-Worsley Catharine Shankel Sonia Mendonca Tara Sager Michael Smith Zvonimir Poljak 《The Canadian veterinary journal. La revue veterinaire canadienne》2016,57(1):46-51
This study investigated the association between presence of respiratory pathogens and development of Canine Infectious Respiratory Disease Complex (CIRDC) in dogs in 5 Canadian small animal clinics. In total, 86 dogs were tested using a commercial PCR respiratory panel; 64 dogs were considered as cases and 22 were control dogs matched by veterinary clinic. No control animals (0/22) were positive for canine parainfluenza virus (CPIV), whereas 27/64 (42%) CIRDC cases were positive. Furthermore, 81% of case dogs tested positive for Mycoplasma cynos, compared with 73% of control dogs. Canine respiratory corona virus (CRCoV) was detected in no control dogs compared with 9.4% of clinical dogs. No animals were positive for any influenza virus type A present in the diagnostic panel. Presence of CPIV was associated (P < 0.01) with the occurrence of CIRDC after adjustment for demographic factors and presence of CRCoV (P = 0.09). 相似文献
8.
9.
10.
Adin DB Maisenbacher HW Ojeda N Fiorello CV Estrada AH Prosek R Citino SB 《American journal of veterinary research》2007,68(2):148-152
OBJECTIVE: To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi). ANIMALS: 20 healthy zebras. PROCEDURES: Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras. RESULTS: Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean +/- SD heart rate of 67 +/- 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras. 相似文献