全文获取类型
收费全文 | 4921篇 |
免费 | 185篇 |
国内免费 | 3篇 |
专业分类
林业 | 249篇 |
农学 | 202篇 |
基础科学 | 36篇 |
750篇 | |
综合类 | 1268篇 |
农作物 | 223篇 |
水产渔业 | 310篇 |
畜牧兽医 | 1571篇 |
园艺 | 110篇 |
植物保护 | 390篇 |
出版年
2023年 | 22篇 |
2022年 | 26篇 |
2021年 | 62篇 |
2020年 | 74篇 |
2019年 | 97篇 |
2018年 | 93篇 |
2017年 | 85篇 |
2016年 | 93篇 |
2015年 | 65篇 |
2014年 | 88篇 |
2013年 | 188篇 |
2012年 | 262篇 |
2011年 | 343篇 |
2010年 | 191篇 |
2009年 | 146篇 |
2008年 | 331篇 |
2007年 | 338篇 |
2006年 | 376篇 |
2005年 | 323篇 |
2004年 | 332篇 |
2003年 | 305篇 |
2002年 | 302篇 |
2001年 | 59篇 |
2000年 | 37篇 |
1999年 | 49篇 |
1998年 | 50篇 |
1997年 | 28篇 |
1996年 | 36篇 |
1995年 | 36篇 |
1994年 | 30篇 |
1993年 | 36篇 |
1992年 | 31篇 |
1991年 | 31篇 |
1990年 | 30篇 |
1989年 | 37篇 |
1988年 | 27篇 |
1987年 | 32篇 |
1986年 | 21篇 |
1985年 | 27篇 |
1984年 | 32篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 26篇 |
1980年 | 23篇 |
1979年 | 15篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1976年 | 19篇 |
1975年 | 16篇 |
1974年 | 24篇 |
排序方式: 共有5109条查询结果,搜索用时 15 毫秒
101.
102.
Mitchell A. Crystal DVM Dominique G. Penninck DVM Michael E. Matz DVM Susan H. Pearson BA Greg O. Freden DVM Richard M. Jakowski DVM 《Veterinary radiology & ultrasound》1993,34(6):438-444
The purpose of this study was to evaluate the usefulness of ultrasound-guided fine-needle aspiration biopsy and core biopsy in the diagnosis of infiltrative gastrointestinal diseases. Six dogs and seven cats with clinical signs of gastrointestinal disease underwent ultrasonography and intestinal lesions were identified. One or more ultrasound-guided fine-needle aspiration biopsy and/or core biopsy procedures were performed in each patient. Each patient also underwent one of the following additional procedures for comparison of results: 1) surgery (n=4), 2) endoscopy (n=2), 3) post mortem exam (n=3), and, 4) for lymphoma diagnosed with ultrasound-guided procedures, response to chemotherapy (n=4). Correct diagnoses were obtained in nine of the 13 patients, incorrect diagnoses in two of the 13 patients, and inconclusive diagnoses in two of the thirteen patients. Of the 16 total ultrasound-guided procedures performed, ten were confirmed as correct, three as incorrect, and three were non-diagnostic. Intestinal lesions with bowel wall thickness greater than 2.0 cm had a higher percentage of correct diagnoses than lesions of lesser wall thickness. Gastric lesions had a higher percentage of correct diagnoses than small and large intestinal lesions. Malignant lesions had a higher percentage of correct diagnoses than benign lesions. There were no complications. Ultrasound-guided gastrointestinal fine-needle aspiration biopsy and core biopsy appears to be a safe, accurate, and rapid procedure for use in the diagnosis of infiltrative gastrointestinal disease. 相似文献
103.
104.
Richard Marchal L Marchal-Delahaut A Lallement P Jeandet 《Journal of agricultural and food chemistry》2002,50(1):177-184
Bovine spongiform encephalopathy caused a situation of crisis leading the public and winemakers to lose their confidence in the use of gelatin as a fining agent and to reject animal proteins in general. Therefore, we started the search for a substitute for gelatin and egg protein by comparing gluten with these fining treatments currently used. This study concerned the fining of a Burgundy red wine (Rully, Controlled Appellation). For 6 g/hL, enzymatically hydrolyzed glutens (EHG) gave better efficiencies than deamidated glutens. The efficiency of the egg proteins treatment was situated between those of the hydrolyzed glutens and deamidated glutens. For 12 and 18 g/hL, turbidities of the wine treated by five glutens were 67 to 86% less than that of the control wine. Better results were obtained with egg proteins for short kinetics particularly. Wine fining with gluten was always better than gelatin treatments. The differences between the five glutens became very small when the dose incorporated in the wine increased. The volumes of lees generated by fining with gluten are situated between the values obtained with egg proteins and gelatin. After fining, immunodetection with gluten polyclonal antibodies failed to detect residual deamidated gluten. 相似文献
105.
106.
Moytri RoyChowdhury Yulin Jia Aaron Jackson Melissa H. Jia Robert Fjellstrom Richard D. Cartwright 《Euphytica》2012,184(1):35-46
The Pi-z gene in rice confers resistance to a wide range of races of the rice blast fungus, Magnaporthe oryzae. The objective of this study was to characterize Pi-z in 111 rice germplasm accessions using DNA markers and pathogenicity assays. The existence of Pi-z in rice germplasm was detected by using four simple sequence repeat (SSR) markers (RM527, AP4791, AP5659-1, AP5659-5) closely
linked to Pi-z, and was verified using pathogenicity assays with an avirulent strain (IE1k) and two virulent races (IB33 and IB49). Among
111 germplasm accessions evaluated, 73 were found to contain the Pi-z gene using both SSR markers and pathogenicity assays. The remaining 38 germplasm accessions were found to be inconsistent
in their responses to the blast races IB33, IEIk and IB49 with expected SSR marker alleles, suggesting the presence of unexpected
SSR alleles and additional R gene(s). These characterized germplasm can be used for genetic studies and marker-assisted breeding for improving blast resistance
in rice. 相似文献
107.
Summary In the early generations of a breeding programme to incorporate the successful Norin 10 semidwarfing genes into adapted tall or standard lines, the bread and durum wheat breeder must be able to recognise and discard those lines that are not homozygous for the dwarfing gene. A method which exploits the gibberellin insensitive reaction of lines carrying the genes combined with a single seed descent technique is described in which most unwanted genotypes may be removed as F2 seedlings. 相似文献
108.
109.
A 12-year-old female spayed domestic short-haired cat presented for lethargy, poor hair coat, alopecia, difficulty walking, and mild polyuria/polydipsia. The cat's skin tore easily in the neck area during routine restraint for blood draw. Physical examination, blood analysis, and ultrasound imaging were all consistent with pituitary-dependent hyperadrenocorticism (PDH) with secondary insulin-resistant diabetes mellitus, which was nonketotic. Insulin therapy, fluids, and diet change were initiated for the diabetes mellitus and the owner reported improvement in clinical signs although the blood glucose measurements remained elevated. Surgical repair of the torn skin was successful. Although a guarded prognosis was given to the owner because of an advanced stage of hyperadrenocorticism, and the limited treatment options currently available for feline PDH, trilostane was agreed on as an initial therapeutic option. The day trilostane was to be initiated, the cat presented with dyspnea and the owner chose to euthanize. Because of the rarity of hyperadrenocorticism disease in the cat, permission was obtained by the owner for a necropsy to confirm suspected PDH as the underlying cause for insulin resistance and skin fragility syndrome. 相似文献
110.