全文获取类型
收费全文 | 7090篇 |
免费 | 338篇 |
国内免费 | 6篇 |
专业分类
林业 | 487篇 |
农学 | 150篇 |
基础科学 | 36篇 |
1325篇 | |
综合类 | 1232篇 |
农作物 | 230篇 |
水产渔业 | 569篇 |
畜牧兽医 | 2694篇 |
园艺 | 200篇 |
植物保护 | 511篇 |
出版年
2023年 | 59篇 |
2022年 | 76篇 |
2021年 | 147篇 |
2020年 | 154篇 |
2019年 | 182篇 |
2018年 | 181篇 |
2017年 | 154篇 |
2016年 | 177篇 |
2015年 | 166篇 |
2014年 | 187篇 |
2013年 | 267篇 |
2012年 | 480篇 |
2011年 | 601篇 |
2010年 | 297篇 |
2009年 | 240篇 |
2008年 | 498篇 |
2007年 | 521篇 |
2006年 | 463篇 |
2005年 | 432篇 |
2004年 | 408篇 |
2003年 | 378篇 |
2002年 | 388篇 |
2001年 | 69篇 |
2000年 | 50篇 |
1999年 | 63篇 |
1998年 | 52篇 |
1997年 | 51篇 |
1996年 | 42篇 |
1995年 | 47篇 |
1994年 | 43篇 |
1993年 | 43篇 |
1992年 | 30篇 |
1991年 | 34篇 |
1990年 | 34篇 |
1989年 | 34篇 |
1988年 | 28篇 |
1987年 | 27篇 |
1986年 | 25篇 |
1985年 | 37篇 |
1984年 | 26篇 |
1983年 | 28篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 23篇 |
1979年 | 23篇 |
1978年 | 15篇 |
1977年 | 15篇 |
1975年 | 11篇 |
1974年 | 13篇 |
1973年 | 17篇 |
排序方式: 共有7434条查询结果,搜索用时 0 毫秒
121.
A multiplex PCR assay for differentiating strongyle eggs from cattle has recently been described; however, the egg disruption and DNA extraction procedures, though effective, are inadequate for large studies or clinical application. The purpose of this research was to evaluate methods for disrupting trichostrongyle eggs, then assess commercial kits for extracting egg DNA using Ostertagia ostertagi as a model species. Egg disruption procedures tested included probe sonication, bath sonication, bead beating, boiling, microwaving, proteinase K/SDS digestion, freezing, and various combinations of the above with the incorporation of sodium dodecyl sulfate. These procedures were evaluated in conjunction with four commercial DNA extraction kits: DNA Stool mini kit and DNeasy Plant kit (Qiagen), Fast DNA kit (QBiogene), and the MAP extraction kit (Tetracore). Results showed that egg disruption was best accomplished with the bead beater and ceramic beads, resulting in 100% disruption within 1min. When DNA extraction was preceded by the isolation of eggs from feces, all procedures except the Fast DNA kit produced PCR-ready DNA from at least two eggs. The DNeasy Plant kit allowed consistent detection of DNA released from one egg. Due to the morphological similarities among trichostrongyle eggs in ruminants, strongyle eggs in equids, and hookworm eggs, the methods described herein may have broad application to other nematodes. 相似文献
122.
Survival of Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in blood of cats used for transfusions 总被引:1,自引:0,他引:1
Gary AT Richmond HL Tasker S Hackett TB Lappin MR 《Journal of Feline Medicine and Surgery》2006,8(5):321-326
Blood transfusions are commonly administered to cats; associated risks include the transmission of various infectious diseases including Mycoplasma haemofelis (Mhf) and 'Candidatus Mycoplasma haemominutum' (Mhm). Blood transfusions in citrate-phosphate-dextrose-adenine (CPDA-1) solution are commonly administered immediately or stored for up to 1 month prior to administration. It is unknown whether Mhf or Mhm survive in this solution or temperature. The purpose of this study was to determine if Mhf or Mhm remain viable after storage in CPDA-1 for varying periods of time. The results provide evidence that transmission of hemoplasmas to na?ve cats occurs after administration of infected feline blood that has been stored in CPDA-1 solution for 1h (Mhf) and 1 week (Mhm). These findings support the recommendation that cats used as blood donors be screened for Mhf and Mhm infections by polymerase chain reaction (PCR) assay prior to use. 相似文献
123.
Schmidt TB Brown MS Larson RL Kleiboeker SB Olson KC Keisler D Carroll JA Berg EP 《American journal of veterinary research》2006,67(7):1192-1198
OBJECTIVE: To determine the effect of dietary supplemental lipoic acid (LA) on serum concentrations of metabolic hormones and acute-phase proteins of steers challenged with infectious bovine rhinotracheitis virus (IBRV). ANIMALS: 32 steers. PROCEDURES: Steers were randomly assigned to 4 treatments: negative control (NC; no LA, no IBRV challenge), control (CON; no LA, IBRV challenge), 16 mg of LA/kg of body weight (BW)/d plus IBRV challenge (LA16), and 32 mg of LA/kg of BW/d plus IBRV challenge (LA32). Following a 21-day adaptation period, CON, LA16, and LA32 steers received IBRV (2 mL/nostril [day 0]); NC steers received saline (0.9% NaCl) solution. Blood samples, nasal swab specimens, BW, and rectal temperatures were obtained 0, 1, 3, 5, 7, 14, and 21 days after challenge. Serum was analyzed for concentrations of haptoglobin, amyloid-A, leptin, and anti-IBRV antibodies. RESULTS: Steers fed LA32 began gaining BW by day 7, whereas BW of CON and LA16 steers declined. Serum haptoglobin concentration of LA32 steers was lower than that of CON and LA16 steers on day 7. Serum neutralization titers for 30 of 32 steers were negative for anti-IBRV antibodies before challenge; however, all steers (including NCs) had antibodies on day 21. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that LA supplementation augmented certain aspects of the immune response; LA32 steers had a more rapid recovery from IBRV viral challenge than did others. 相似文献
124.
John H. Rossmeisl Jr. DVM MS DACVIM Michael A. Higgins DVM Dennis J. Blodgett DVM PhD DABVT Matthew Ellis DVM Delbert E. Jones MS 《Journal of Veterinary Emergency and Critical Care》2006,16(3):208-214
Objective: To report the manifestations, history, and pathophysiologic basis of disease in 2 dogs with Amanita muscaria toxicosis. Case summaries: Two dogs were evaluated for an acute onset of gastroenteritis and seizures. A. muscaria toxicosis was suspected in each dog after confirmation of environmental exposure and visualization of ingested mushrooms in vomitus. The diagnosis was confirmed following identification of toxic Amanita metabolites in the urine and serum of each dog. Administration of supportive and symptomatic therapies resulted in the complete recovery of each animal. Unique information provided: Ingestion of the mushroom, A. muscaria, by dogs can result in acute gastrointestinal distress that precedes a potentially life‐threatening central neurologic syndrome characterized by seizures, tremors, and somnolence. Central nervous system dysfunction results primarily from the actions of ibotenic acid and its decarboxylation product, muscimol, which are analogues of the neurotransmitters glutamate and γ‐aminobutyric acid (GABA), respectively. Identification of these toxins in the urine and serum of affected dogs using high‐performance liquid chromatography (HPLC) provides a definitive diagnosis. 相似文献
125.
Blackwell MJ 《Journal of veterinary medical education》2006,33(3):408-410
The context of the conference presentation that gave rise to this article was the importance of veterinarians becoming more engaged in the public-health challenges of today. During the presentation, I sought to point out some of the pressing reasons why. Of particular concern to me are the missed opportunities to help influence human health and well-being as private veterinary practitioners in addition to public-practice veterinarians. Key elements: Public health, the protection and improvement of community health by organized community effort; the global community, the entire world; social responsibility, being, as members of society, morally and legally responsible for the welfare of human beings; terrorism, the systematic use of terror (fear), especially as a means of coercion (it is always local!); system integration, the interaction of interdependent groups to form a unified whole. 相似文献
126.
Retinoblastoma in the eye of a llama (Llama glama) 总被引:1,自引:0,他引:1
Fugaro MN Kiupel M Montiani-Ferreira F Hawkins JF Janovitz EB 《Veterinary ophthalmology》2005,8(4):287-290
ANIMAL STUDIED: A 6-year-old, pregnant female llama experienced a 6-month history of epiphora, buphthalmos, and acute loss of vision in the left eye. The condition was unresponsive to topical antimicrobial and anti-inflammatory therapy and progressed to corneal rupture. PROCEDURES: Transpalpebral enucleation was performed and an intraorbital silicone prosthesis was implanted. The eye was fixed in formalin and processed according to routine paraffin technique. Sections of a mass were immunohistochemically prepared routinely and stained for glial fibrillary acidic protein (GFAP), S-antigen, and rhodopsin. RESULTS: Gross, histopathologic, and immunohistochemical analysis revealed a retinal tumor consistent with a retinoblastoma. The neoplastic tissue formed Flexner-Wintersteiner and Homer-Wright rosettes, originated from the retina, and demonstrated photoreceptor differentiation with S-antigen and rhodopsin expression. Neoplastic cells were negative for GFAP. Four years after enucleation, the llama showed no signs of recurrent neoplasia. CONCLUSIONS: This report describes the diagnosis and successful treatment of the first known retinoblastoma in a llama. 相似文献
127.
It is unlikely that human beings acquire a zoonotic infection from healthy cats without ectoparasites. The benefits of cat ownership to human mental health are well established. Veterinarians and physicians should work together closely to provide accurate information to cat owners so that logical decisions concerning cat ownership can be made by the owner. 相似文献
128.
129.
The medical records of 31 dogs treated for envenomation by the Eastern Diamondback Rattlesnake (Crotalus adamanteus) were reviewed. Twenty-four of 25 dogs that survived were hospitalized for an average of 4.3 days. The most common presenting signs were tachycardia, swelling/edema, depressed mentation, tachypnea, and bleeding puncture wounds. Thirteen (42%) of the 31 dogs were presented with or developed cardiac arrhythmias, predominantly ventricular premature contractions. Hematological disorders, including defibrination, elevated fibrin split products, hemolytic anemia, thrombocytopenia, and prolonged clotting times, were recorded in 81% of the dogs. Polyvalent crotalid antivenin was administered (mean of 4.0 vials per dog) to 88% of the surviving dogs and 50% of the nonsurviving dogs. 相似文献
130.
Jonas Malmsten Lennart S?derquist Carl-Gustaf Thulin Dolores Gavier Widén Lisa Yon Michael R Hutchings Anne-Marie Dalin 《Acta veterinaria Scandinavica》2014,56(1):23