全文获取类型
收费全文 | 1209篇 |
免费 | 60篇 |
国内免费 | 1篇 |
专业分类
林业 | 67篇 |
农学 | 35篇 |
基础科学 | 7篇 |
118篇 | |
综合类 | 326篇 |
农作物 | 83篇 |
水产渔业 | 31篇 |
畜牧兽医 | 516篇 |
园艺 | 16篇 |
植物保护 | 71篇 |
出版年
2022年 | 10篇 |
2020年 | 16篇 |
2019年 | 24篇 |
2018年 | 17篇 |
2017年 | 18篇 |
2016年 | 29篇 |
2015年 | 25篇 |
2014年 | 23篇 |
2013年 | 42篇 |
2012年 | 38篇 |
2011年 | 40篇 |
2010年 | 33篇 |
2009年 | 20篇 |
2008年 | 47篇 |
2007年 | 40篇 |
2006年 | 30篇 |
2005年 | 36篇 |
2004年 | 34篇 |
2003年 | 35篇 |
2002年 | 31篇 |
2001年 | 21篇 |
2000年 | 33篇 |
1999年 | 19篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 11篇 |
1992年 | 30篇 |
1991年 | 23篇 |
1990年 | 36篇 |
1989年 | 26篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 21篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 16篇 |
1982年 | 14篇 |
1981年 | 9篇 |
1979年 | 12篇 |
1976年 | 11篇 |
1975年 | 10篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1972年 | 9篇 |
1971年 | 15篇 |
1970年 | 19篇 |
1969年 | 29篇 |
1968年 | 38篇 |
1967年 | 35篇 |
1966年 | 21篇 |
排序方式: 共有1270条查询结果,搜索用时 15 毫秒
31.
Mariëlle M.C. Goossens Richard W. Nelson Edward C. Feldman Stephen M. Griffey 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1998,12(1):1-6
Medical records of 104 cats with diabetes mellitus were reviewed. Information from 54 cats that had multiple blood glucose concentrations evaluated at least 5 times over a minimum of 3 months, beginning at the time insulin treatment was initiated, was used to evaluate the efficacy of insulin in treating diabetes mellitus. Fourteen of 54 cats were treated with protamine zinc insulin (PZI), 26 with ultralente insulin, and 14 with lente insulin. Six, 29, and 19 cats had good, mediocre, and poor glycemic control, respectively, based on mean blood glucose concentrations, whereas 31, 21, and 2 owners thought clinical response was good, mediocre, and poor, respectively. No significant difference was found in glycemic control among cats treated with PZI, ultralente, or lente insulin. Glycemic control was significantly (P < .05) better in 33 cats without than in 21 cats with concurrent disease. All 104 cats were used to calculate survival data. Fifty-one of 104 cats were alive at the time of the study. Mean (± standard deviation [SD]) and median survival times were 24 (± 16) and 20 months, respectively, in the 51 cats still alive at the end of the evaluation, and 25 (± 4) and 17 months, respectively, in the 53 cats that had died during the period of evaluation. Pancreatic abnormalities identified in 37 cats that underwent necropsy included chronic pancreatitis (n = 17), acute to subacute pancreatitis (n = 2), exocrine pancreatic adenocarcinoma (n = 7) and adenoma (n = 1), islet cell atrophy and vacuolar degeneration (n = 27), and islet amyloidosis (n = 8). No association was found between glycemic control and islet amyloidosis or exocrine pancreatic neoplasia, or between survival time and chronic pancreatitis, islet amyloidosis, or exocrine pancreatic neoplasia. In conclusion, diabetic cats evaluated in this study showed a variable response to exogenously administered insulin, ranging from excellent to poor. By maintaining mean blood glucose concentrations under 300 mg/dL, clinical signs were improved, and owners were satisfied with insulin treatment. Concurrent potentially insulin-antagonistic diseases were common and deleteriously affected glycemic control and survival time. 相似文献
32.
Mangroves and Salt Marshes - 相似文献
33.
R W Nelson C A Himsel E C Feldman G D Bottoms 《American journal of veterinary research》1990,51(9):1357-1362
Glucose tolerance and insulin response were evaluated in 9 normal-weight and 6 obese cats after IV administration of 0.5 g of glucose/kg of body weight. Blood samples for glucose and insulin determinations were collected immediately prior to and 2.5, 5, 7.5, 10, 15, 30, 45, 60, 90, and 120 minutes after glucose infusion. Baseline glucose concentrations were not significantly different between normal-weight and obese cats; however, mean +/- SEM glucose tolerance was significantly impaired in obese vs normal-weight cats after glucose infusion (half time for glucose disappearance in serum--77 +/- 7 vs 51 +/- 4 minutes, P less than 0.01; glucose disappearance coefficient--0.95 +/- 0.10 vs 1.44 +/- 0.10%/min, P less than 0.01; insulinogenic index--0.20 +/- 0.02 vs 0.12 +/- 0.01, P less than 0.005, respectively). Baseline serum insulin concentrations were not significantly different between obese and normal-weight cats. Insulin peak response after glucose infusion was significantly (P less than 0.005) greater in obese than in normal-weight cats. Insulin secretion during the first 60 minutes (P less than 0.02), second 60 minutes (P less than 0.001), and total 120 minutes (P less than 0.0003) after glucose infusion was also significantly greater in obese than in normal-weight cats. Most insulin was secreted during the first hour after glucose infusion in normal-weight cats and during the second hour in obese cats. The impaired glucose tolerance and altered insulin response to glucose infusion in the obese cats was believed to be attributable to deleterious effects of obesity on insulin action and beta-cell responsiveness to stimuli (ie, glucose). 相似文献
34.
Anti-erythrocytic immunoglobulins in serum and colostrum of 124 anaplasmosis-vaccinated cows were detected with a saline agglutination test. Positive results were correlated with the occurrence of neonatal isohemolytic anemia (NIA) in calves and were used to predict the occurrence of NIA. The disease was prevented by withholding colostrum from calves with a high potential for NIA. 相似文献
35.
A microenzyme-linked immunosorbent assay (dot-ELISA) was modified for making an immunodiagnosis of Fasciola hepatica infections in sheep. Sheep were alloted as follows: group I-3 controls and 4 principals, each inoculated with 500 metacercariae; group II-3 controls and 7 principals, each inoculated with 250 metacercariae; and group III-3 controls and 7 principals, each inoculated with 500 metacercariae. Blood and fecal samples were collected from each animal every 2 weeks for 16 weeks. Presence (or absence) of flukes was confirmed by fecal examinations and examination of dissected livers at necropsy of the sheep. The dot-ELISA incubations were done at ambient room temperature. Nitrocellulose disks dotted with 1 microliter (50 ng of protein) of F hepatica excretory/secretory products were placed in 96-well tissue culture plates. After nonspecific binding sites on the disks were bound with bovine serum albumin-triethanolamine-buffered saline solution, dilutions (1:2) of positive- and negative-control serum samples or experimental serum samples were placed in appropriate wells for a 30-minute incubation. Wells were washed (3 times), and 50 microliters of horseradish peroxidase conjugated rabbit anti-sheep immunoglobulin G was added to each well for a 30-minute incubation and then aspirated. Substrate solution (4-chloro-1-naphthol, methanol, triethanolamine-buffered saline solution, and H2O2; 50 microliters) was added for a 30-minute incubation and then aspirated. Disks were air dried for visualization: solid purple dot = positive sample, or no dot = negative sample.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
36.
Denise A. Elliott Richard W. Nelson Edward C. Feldman Larry A. Nea 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1997,11(3):161-165
Blood glycosylated hemoglobin (GHb) concentration was quantified in 84 healthy cats, 9 cats with stress-induced hyperglycemia, 37 cats with newly diagnosed diabetes mellitus, and 122 diabetic cats treated with insulin or glipizide. Diabetic control was classified as good or poor in insulin-treated or glipizide-treated cats based on review of history, physical examination findings, changes in body weight, and measurement of blood glucose concentrations. Blood GHb concentration was determined using an affinity chromatography assay. Mean blood GHb concentration was similar for healthy normoglycemic cats and cats with transient, stress-induced hyperglycemia, but was significantly (P < .001) higher in untreated diabetic cats when compared with healthy normoglycemic cats. Mean blood GHb concentration was significantly (P < .001) higher in 84 cats with poorly controlled diabetes mellitus when compared with 38 cats in which the disease was well controlled. Mean blood GHb concentration decreased significantly (P < .01) in 6 cats with untreated diabetes mellitus after insulin and dietary treatment. A similar significant (P < .01) decrease in mean blood GHb concentration occurred in 7 cats with poorly controlled diabetes mellitus after diabetic control was improved by an increase in insulin dosage from 1.1 ± 0.9 to 1.4 ± 0.6 U/kg/ 24 h and by feeding a diet containing increased fiber content and in 6 cats with transient diabetes mellitus 8.2 ± 0.6 weeks after discontinuing insulin treatment. There was a significant (P< .01) stress-induced increase in mean fasting blood glucose concentration and mean blood glucose concentration for 12 hours after administration of insulin or glipizide but no change in mean blood GHb concentration in 5 docile diabetic cats 12.2 ± 0.4 weeks after the cats became fractious as a result of frequent hospitalizations and blood samplings. Results of this study suggest that evaluation of blood GHb concentration may be a clinically useful tool for monitoring glycemic control of diabetes in cats. 相似文献
37.
Nelson A 《Science (New York, N.Y.)》1914,39(1017):921-927
38.
J J Nelson 《Journal of the Association of Official Analytical Chemists》1976,59(2):243-250
Quantitation of o- and p-sulfamoylbenzoic acid residues in saccharin and its sodium salt is achieved by a method comprising methanolic extraction and high-performance ion exchange chromatography. A commercially available anion exchange column was employed with an aqueous buffered (pH 9.2) mobile phase. As little as 80 ppm of the ortho-isomer and 25 ppm of the para-isomer can be accurately determined. The levels of detectability (2 times noise) are estimated as 8 ppm (0.16 mug on column) and 2.5 ppm (0.05 mug on column), respectively. Recoveries from saccharin ranged from 92.7 to 96.5% (ortho) and from 92.2 to 103.3% (para). Recoveries from the sodium salt ranged from 93.1 to 104.4% (ortho) and from 93.5 to 97.8% (para). Of 9 other potential saccharin impurities tested separately, only one was found to interfere slightly in the chromatographic part of the procedure. 相似文献
39.
Flavobacterium columnare is the causative agent of columnaris disease. The presence of lesions on the gills, skin and fins of diseased fish suggests that F. columnare is able to utilize fish skin mucus as a substrate for growth and that exposure to this material would alter the expression of genes involved in the colonization of the outer surfaces of the fish. Growth, biofilm formation, extracellular protease production and changes in protein expression of F. columnare strain C#2 cultured in media supplemented with juvenile Atlantic salmon skin mucus were compared with the same media without mucus. C#2 was able to grow by using mucus as the sole nutrient source. Growth in mucus-containing media induced cells to grow as a biofilm and extracellular protease activity increased in mucus-containing cultures. SDS-PAGE protein profiles showed that expression of six extracellular proteins increased in mucus-containing media. These results demonstrate that salmon surface mucus promotes the growth of F. columnare and that exposure to mucus alters the growth characteristics of this bacterium with regard to protease production and biofilm formation. Further characterization of mucus-induced physiological changes will increase our understanding of the basis of virulence of this economically important fish pathogen. 相似文献
40.