全文获取类型
收费全文 | 185篇 |
免费 | 6篇 |
专业分类
林业 | 15篇 |
农学 | 2篇 |
49篇 | |
综合类 | 13篇 |
农作物 | 5篇 |
水产渔业 | 6篇 |
畜牧兽医 | 86篇 |
园艺 | 4篇 |
植物保护 | 11篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 8篇 |
2012年 | 17篇 |
2011年 | 15篇 |
2010年 | 3篇 |
2009年 | 13篇 |
2008年 | 14篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 19篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2000年 | 2篇 |
1998年 | 1篇 |
排序方式: 共有191条查询结果,搜索用时 31 毫秒
11.
Khaitovich P Hellmann I Enard W Nowick K Leinweber M Franz H Weiss G Lachmann M Pääbo S 《Science (New York, N.Y.)》2005,309(5742):1850-1854
The determination of the chimpanzee genome sequence provides a means to study both structural and functional aspects of the evolution of the human genome. Here we compare humans and chimpanzees with respect to differences in expression levels and protein-coding sequences for genes active in brain, heart, liver, kidney, and testis. We find that the patterns of differences in gene expression and gene sequences are markedly similar. In particular, there is a gradation of selective constraints among the tissues so that the brain shows the least differences between the species whereas liver shows the most. Furthermore, expression levels as well as amino acid sequences of genes active in more tissues have diverged less between the species than have genes active in fewer tissues. In general, these patterns are consistent with a model of neutral evolution with negative selection. However, for X-chromosomal genes expressed in testis, patterns suggestive of positive selection on sequence changes as well as expression changes are seen. Furthermore, although genes expressed in the brain have changed less than have genes expressed in other tissues, in agreement with previous work we find that genes active in brain have accumulated more changes on the human than on the chimpanzee lineage. 相似文献
12.
Alt A Lammens K Chiocchini C Lammens A Pieck JC Kuch D Hopfner KP Carell T 《Science (New York, N.Y.)》2007,318(5852):967-970
DNA polymerase eta (Pol eta) is a eukaryotic lesion bypass polymerase that helps organisms to survive exposure to ultraviolet (UV) radiation, and tumor cells to gain resistance against cisplatin-based chemotherapy. It allows cells to replicate across cross-link lesions such as 1,2-d(GpG) cisplatin adducts (Pt-GG) and UV-induced cis-syn thymine dimers. We present structural and biochemical analysis of how Pol eta copies Pt-GG-containing DNA. The damaged DNA is bound in an open DNA binding rim. Nucleotidyl transfer requires the DNA to rotate into an active conformation, driven by hydrogen bonding of the templating base to the dNTP. For the 3'dG of the Pt-GG, this step is accomplished by a Watson-Crick base pair to dCTP and is biochemically efficient and accurate. In contrast, bypass of the 5'dG of the Pt-GG is less efficient and promiscuous for dCTP and dATP as a result of the presence of the rigid Pt cross-link. Our analysis reveals the set of structural features that enable Pol eta to replicate across strongly distorting DNA lesions. 相似文献
13.
Mustonen K Ala-Kurikka E Orro T Peltoniemi O Raekallio M Vainio O Heinonen M 《Veterinary journal (London, England : 1997)》2011,190(1):55-59
The efficacy of ketoprofen in the treatment of non-infectious lameness in sows was examined in a double-blinded study. Two dose rates of oral ketoprofen were compared to placebo treatment over five consecutive days. Lameness was assessed with a five-grade scoring system prior to and on the last day of the treatment. The rate of treatment success was 54.3% for the ketoprofen 4mg/kg group (n=46), 53.2% for the ketoprofen 2mg/kg group (n=47) and 20.8% for the pigs in the placebo group (n=48). The difference between both ketoprofen groups and the placebo group was significant (P=0.001), but there was no difference between the two ketoprofen groups (P=0.78). Oral ketoprofen was well tolerated and no adverse events were observed. As lameness is a very common problem in sows, oral ketoprofen appeared to be a practical way to alleviate pain and improve the welfare of sows. 相似文献
14.
Rüfenacht S Bögli-Stuber K Bodmer T Jaunin VF Jmaa DC Gunn-Moore DA 《Journal of Feline Medicine and Surgery》2011,13(3):195-204
OVERVIEW: Mycobacterium microti infection is infrequently described in cats in the veterinary literature. It can be one of a large number of possible differential diagnoses in a feline patient with dermal nodules and non-healing draining ulcers, and can occasionally spread to involve the lungs and/or other areas of the body. CASE SUMMARY: This report describes the clinical signs, eventual diagnosis and variable response to treatment in a cat in Switzerland with recurrent cutaneous M microti infection. Only after several diagnostic and therapeutic attempts, over more than 2 years, was the species of Mycobacterium finally identified and targeted therapy given. PRACTICAL RELEVANCE: For any cat in which there is even a low suspicion of mycobacterial infection, the authors recommend that an aggressive diagnostic approach is taken. Tissue specimens should be collected and frozen early on, and, as soon as acid-fast bacilli are detected, samples should be sent to a mycobacterial reference laboratory for definitive identification. LITERATURE REVIEW: A review of the literature relating to the aetiopathogenesis, diagnosis and management of M microti infection in cats and dogs is included. This is supplemented with clinical and therapeutic experience gained from this case and other, unpublished cases managed over the past 15 years by one of the authors (DGM). 相似文献
15.
Katja Broeker Sabine Fehser Klaus B. Tenberge Bruno M. Moerschbacher 《Physiological and Molecular Plant Pathology》2011,76(1):27-33
Rust fungi like Puccinia graminis f. sp. tritici are known to change their cell wall properties upon entering the plant tissue. Immunohistochemistry revealed the cellular localization of two class III chitin synthase isoforms in rust mycelia developing on and in the host plant. Isoform IIIa is restricted to fungal infection structures growing on the surface of the plant, such as germ tubes and, predominantly, appressoria. Isoform IIIb is found exclusively in haustoria developed inside the plant. Thus, the rust fungus uses at least two chitin synthase isoforms with specialized functions in the differentiation of infection structures during the biotrophic plant-pathogen-interaction. 相似文献
16.
It was the aim of this placebo-controlled study to evaluate the analgesic efficacy of the NASAID carprofen and the pure m-agonist levomthadone over a five-day postoperative evaluation period in dogs with fractures of the humerus or the femur (n = 30). Pain and sedation evaluation was carried out with a visual analogues system (VAS) and with the aid of a numerical estimation scale(NRS). The degree of lameness, the pain treshhold, the glucose and cortisol concentration curves as well as the respiration and heart rate and the systolic blood pressure were used as further pain indicators and to identify drug side effects. The levomethadon group displayed the lowest degree of pain on postoperative examination on the first day. On days 2 to 5, the carprofen group showed the lowest degree of pain in comparison to the placebo group. The levomethadon- and the carprofen group showed no statistically proven differences from day 2 on. Due to great variations in the pain scores and comparatively high median pain score especially on the first day of this study, the efficacy of all analgesics evaluated here must be regarded as insufficient in many cases. Only the parameter nociceptive pain treshhold showed a little, the degree of lameness, the glucose and cortisol levels showed no close correlation to the VAS and NRS pain scores and were therefore of little usefulness as postoperative pain indicators. No relevant clinical side effects caused by the used analgesics were detected in the kidney, the liver, the gastrointestinal tract and the circulatory system in this study. Rather, traumatically induced elevation of enzyme levels improves or normalised until the 5th day of the study. In addition, no negative effect on wound healing was noted, especially for carprofen. Therefore, the evaluated analgesics seems to be adequate for postoperative pain therapy also in fracture patients (trauma patients). However, the efficacy of all analgesics evaluated here must be regarded as insufficient in many cases. 相似文献
17.
Grossmann K Weniger B Baljer G Brenig B Wieler LH 《Berliner und Münchener tier?rztliche Wochenschrift》2005,118(11-12):456-463
18.
OBJECTIVE: To determine the outcome of dogs and cats in which a tension band technique was used to stabilize traumatic fractures and luxations of the thoracolumbar vertebrae. DESIGN: Retrospective study. ANIMALS: 38 client-owned animals (22 dogs and 16 cats) weighing between 1.4 and 45 kg (3 and 99 lb). PROCEDURE: Medical records of cats and dogs that underwent tension band stabilization of thoracolumbar fractures and luxations at the University of Zurich between 1993 and 2002 were reviewed. The stabilization technique was a modification of a spinal stapling technique with a figure 8 hemicerclage wire placed in a tension band fashion across the lesion. Neurologic status, lesion location and type, and concomitant traumatic injuries were assessed from the medical records and preoperative radiographs. Clinical outcome and complications were determined through follow-up examinations or telephone conversations with the owners. RESULTS: Complete or satisfactory neurologic recovery was achieved in 30 (79%) patients. Seven patients were euthanatized (6 owing to poor neurologic recovery and 1 owing to implant failure), and 1 dog was managed at home despite paraplegia. Clinically, only 4 patients (11%) had evidence of implant or fixation failure; all were dogs weighing > 16 kg (35 lb). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the tension band technique may be appropriate for stabilization of fractures and luxations of the thoracolumbar vertebrae in cats and small- or medium-sized dogs. In larger dogs, fixation strength may be insufficient to stabilize certain fracture types and ancillary external or internal fixation methods may be needed. 相似文献
19.
Warnock JJ Baltzer WI Duesterdieck-Zellmer K Ott J 《Research in veterinary science》2012,93(3):1472-1480
Tissue engineering is being investigated as a means for treating avascular meniscal injury or total meniscal loss in human and veterinary patients. The purpose of this study was to determine if an arthroscopic tissue shaver can be used to collect viable synoviocytes for in vitro culture during therapeutic stifle arthroscopy, with the long term goal of producing autologous meniscal fibrocartilage for meniscal tissue engineering. Synovium was harvested arthroscopically from 13 dogs with naturally occurring cranial cruciate ligament deficiency and obtained from 5 dogs with patellar luxation via arthrotomy. Cells harvested via arthroscopy and arthrotomy were treated with a chondrogenic growth factor protocol and analyzed for meniscal-like matrix constituents including collagens type I, II, and glycosaminoglycans. Arthrotomy and Arthroscopic origin cells formed contracted tissues containing collagen I, II and small amounts of GAG. These surgical methods provide clinically relevant access to synoviocytes for potential use in meniscal tissue engineering. 相似文献
20.
Nostell K Bröjer J Höglund K Edner A Häggström J 《Veterinary journal (London, England : 1997)》2012,191(2):171-175
Branding is the traditional and well-established method used to mark horses, but recently microchip transponders for implantation have become available. In this study, behaviour, physiological stress variables and skin temperature in foals were determined in response to hot-iron branding (n=7) and microchip implantation (n=7). Salivary cortisol concentrations increased in response to branding (1.8 ± 0.2 ng/mL) and microchip implantation (1.4 ± 0.1ng/mL), but cortisol release over time did not differ. In response to both manipulations there was a transient increase in heart rate (P<0.001) and heart rate variability (P<0.01). Branding and microchip implantation induced a comparable aversive behaviour (branding, score 3.86 ± 0.85; microchip, score 4.00 ± 0.82). Both techniques thus caused similar physiological and behavioural changes indicative of stress. Acutely, implantation of a microchip was as stressful as branding in foals. Branding caused a necrotising skin burn lasting at least 7 days. Moreover branding, but not microchip implantation (P<0.001), was accompanied by a generalized increase in skin temperature which was comparable to low degree post-burn hypermetabolism in humans. 相似文献