全文获取类型
| 收费全文 | 492篇 |
| 免费 | 18篇 |
专业分类
| 林业 | 35篇 |
| 农学 | 6篇 |
| 基础科学 | 3篇 |
| 85篇 | |
| 综合类 | 102篇 |
| 农作物 | 26篇 |
| 水产渔业 | 37篇 |
| 畜牧兽医 | 166篇 |
| 园艺 | 11篇 |
| 植物保护 | 39篇 |
出版年
| 2023年 | 4篇 |
| 2021年 | 9篇 |
| 2020年 | 9篇 |
| 2019年 | 9篇 |
| 2018年 | 10篇 |
| 2017年 | 12篇 |
| 2016年 | 16篇 |
| 2015年 | 8篇 |
| 2014年 | 16篇 |
| 2013年 | 20篇 |
| 2012年 | 25篇 |
| 2011年 | 40篇 |
| 2010年 | 26篇 |
| 2009年 | 12篇 |
| 2008年 | 32篇 |
| 2007年 | 20篇 |
| 2006年 | 23篇 |
| 2005年 | 30篇 |
| 2004年 | 42篇 |
| 2003年 | 25篇 |
| 2002年 | 34篇 |
| 2001年 | 6篇 |
| 2000年 | 4篇 |
| 1999年 | 2篇 |
| 1998年 | 5篇 |
| 1997年 | 3篇 |
| 1996年 | 2篇 |
| 1995年 | 4篇 |
| 1993年 | 3篇 |
| 1992年 | 2篇 |
| 1991年 | 4篇 |
| 1990年 | 4篇 |
| 1989年 | 2篇 |
| 1988年 | 3篇 |
| 1987年 | 4篇 |
| 1986年 | 6篇 |
| 1985年 | 7篇 |
| 1979年 | 3篇 |
| 1978年 | 4篇 |
| 1972年 | 1篇 |
| 1971年 | 3篇 |
| 1970年 | 1篇 |
| 1968年 | 1篇 |
| 1966年 | 1篇 |
| 1965年 | 1篇 |
| 1963年 | 1篇 |
| 1961年 | 1篇 |
| 1959年 | 2篇 |
| 1958年 | 1篇 |
| 1953年 | 1篇 |
排序方式： 共有510条查询结果，搜索用时 15 毫秒
41.
Mycorrhizae are ubiquitous symbiosis which can mediate uptake of some plant nutrients. In polluted soils they could be of great importance in heavy metal availability and toxicity to plants. Mycorrhizae have also been reported to protect plants against toxic metals. We investigated the occurrence and infectivity of arbuscular mycorrhizal (AM) spores as affected by heavy metal levels and other soil properties in Norwegian soils collected from heavy metal polluted, high natural background and non-polluted areas. Spore numbers, mycorrhizal infectivity and spore germination of indigenous mycorrhizal fungi and of a reference strain (Glomus mosseae) in soils showed lower values in two soils with high metal concentrations and in one soil with a low pH. Mycorrhizal infectivity was negatively correlated with extractable metals. Spore number and mycorrhizal infectivity in a soil with naturally high heavy metal content were not different to in non-polluted soils, and indigenous AM fungi appeared more tolerant to metals than those in non-polluted soils. Mycorrhizal infectivity, expressed as MSI50 values, was significantly correlated (r′=0.89, P< 0.05) with the percentage of germinating G. mosseae spores in the soils. However, the number of spores per volume of soil was not significantly correlated with infectivity or spore germination of the reference strain. The spore germination method is discussed as a bioassay of heavy metal toxicity in soil. 相似文献
42.
Feng-He Wang Bin Zhao Fan Zhang Jay Gao Hao-Tian Hao Shengtian Zhang 《Journal of Soils and Sediments》2016,16(2):371-381
Purpose
The main objectives of the study were to (1) develop a one-step facile procedure for synthesizing a new chemical amendment agent with three chelating groups for solidifying multiple heavy metals, called sixthio guanidine acid (SGA), using guanidine hydrochloride and carbon disulfide as raw reactants and (2) assess its biodegradability, solidification effectiveness, and leachability in remedying soils contaminated with multiple heavy metals of various concentrations compared with other traditional amendment agents.Materials and methods
Polluted soil samples were collected near a metalliferous mining site of Qixiashan in the southeast of Nanjing, China. Their concentrations were determined at 22.15–320 mg kg?1 for As, 3.30–29.31 mg kg?1 for Cd, 115.66–158.65 mg kg?1 for Ni, 165.04–1677.06 mg kg?1 for Pb, and 355.6–2426.91 mg kg?1 for Zn. Biodegradability of SGA was assessed in accordance with GB/T 21831-2008 and OECD-301D. Total concentration of heavy metals was determined according to ISO11466:1995. A modified three-step sequential Community Bureau of Reference (BCR) extraction procedure was used to examine speciation of heavy metals in the soil sample, and concentrations of heavy metals were measured by using inductively coupling plasma optical emission spectrometry (ICP-OES). Leachate extraction tests were carried out before and after the soil sample was solidified with different amendments in accordance with HJ/T 557-2009.Results and discussion
It is found that the optimal conditions for SGA synthesis are a molar ratio of 4:1, a reaction temperature of 40 °C, and a reaction time of 2 h. Under such conditions, SGA yield is achieved as high as 91.5 %. The bioavailability and mobility of As, Cd, Ni, Pb, and Zn in highly contaminated soils can be reduced via using SGA. Our results indicate that SGA is nonbiodegradative and much more effective than other traditional chemical amendment agents in that it is highly effective in comprehensively solidifying As, Cd, Ni, and Pb.Conclusions
SGA has the potential for comprehensive in situ remediation of soils contaminated with several heavy metal elements of various concentration levels, and such findings may be used as a guide to design new chemical amendment agents for rehabilitating soils contaminated with heavy metals.43.
44.
Resolution of a Left Ureteral Stone Using Electrohydraulic Lithotripsy in a Thoroughbred Colt 总被引：1，自引：0，他引：1
Lynn D. Rodger Gary P. Carlson Michael E. Moran Tom B. Yarbrough John R. Pascoe Jay A. Reynolds 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(4):280-282
A 3-year-old Thoroughbred colt was presented for evaluation of azotemia and anorexia. Physical examination revealed a ureterolith in the left ureter, approximately 10 cm from the bladder, which was thought to obstruct urine flow by approximately 90% when viewed cystoscopically. Ultrasonographic examination of both kidneys revealed indistinct corticomedullary junctions, and the right kidney was more hyperechoic. A percutaneous biopsy of the right kidney revealed chronic interstitial nephritis with marked interstitial medullary fibrosis. Medical therapy consisting of IV fluids, sodium chloride PO, and ammonium chloride PO was initiated. Ureteroscopic electrohydraulic lithotripsy via a perineal urethrostomy was used to successfully remove the stone. Klebsiella oxytoca , which responded to oral enrofloxacin therapy, was cultured from the urine after surgery. Azotemia resolved and the horse resumed training. 相似文献
45.
Efficacy and Toxicity of Doxorubicin/Cyclophosphamide Maintenance Therapy in Dogs with Multicentric Lymphosarcoma 总被引：1，自引：1，他引：0
G. Sylvester Price DVM Rodney L. Page MS DVM Bernard M. Fischer DVM Jay F. Levine DVM MPH Thomas M. Gerig PhD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1991,5(5):259-262
Doxorubicin/cyclophosphamide were evaluated as maintenance drugs for dogs with multicentric lymphosarcoma (n = 28). Median remission time of all dogs was 173 days. Remission duration was shorter, however, in dogs with stage IV/V disease, in dogs with pretreatment hypoalbuminemia, and in dogs that had received glucocorticoids before initiation of chemotherapy (P less than 0.04). Nineteen dogs were evaluable for toxicity. Dose-limiting gastrointestinal toxicosis was observed in three dogs, neutropenia was observed in three dogs, and cardiomyopathy was observed in three dogs. The doxorubicin/cyclophosphamide protocol described in this report is safe and effective in treating canine multicentric lymphosarcoma. Clinical stage, pretreatment steroid therapy, and hypoalbuminemia are prognostic factors for response to this protocol. 相似文献
46.
Debra C. Sellon Jay Levine Everett Millikin Kate Palmer Carol Grindem Patrice Covington 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1996,10(3):127-132
The records of 3,952 equine patients presenting to the Veterinary Teaching Hospital at North Carolina State University College of Veterinary Medicine were evaluated to determine risk factors associated with thrombocytopenia. Of 2,346 horses from which a CBC was obtained, 35 (1.49%) were thrombocytopenic (platelet count < 75,000/μL). A reference population of 189 horses with normal platelet counts (75,000 to 300,000/μL) was also studied. Standardbred horses were at increased risk for thrombocytopenia. but age and gender were not identified as significant risk factors. Horses with infectious or inflammatory diseases were at increased risk for thrombocytopenia. The potential association of clinical and clinicopathologic factors with thrombocytopenia were assessed by reviewing a series of multiple logistic regression models. Clinical and clinicopathologic variables significantly associated with thrombocytopenia in the final model included increased PCV, increased band neutrophil count, increased total WBC, and decreased plasma protein concentration. Increased mature neutrophil count was associated with normal platelet counts. Thrombocytopenic horses were significantly more likely to die or be euthanized than were horses with normal platelet counts. J Vet Intern Med 1996;10:127–132. Copyright © 1996 by the American College of Veterinary Internal Medicine . 相似文献
47.
Recent studies have suggested that various aspects of reproductive biology are strikingly different among the many herds of feral horses and ponies (E. caballus) in North America. The greatest differences include (1) sharply seasonal versus year-round mating and foaling patterns, (2) mare behavior at the time of parturition, (3) forced copulation and incest, (4) exclusive breeding by a single harem stallion vs breeding by two or more stallions, and (5) fecundity. The causes for these differences are discussed in terms of genetic origins of the various herds, the length of time each herd has been in a free-roaming state and subject to the forces of natural selection, the ecology of the ranges inhabited by these horses, population density, and sex ratios. 相似文献
48.
49.
50.