全文获取类型
收费全文 | 6123篇 |
免费 | 278篇 |
国内免费 | 1篇 |
专业分类
林业 | 450篇 |
农学 | 139篇 |
基础科学 | 49篇 |
1038篇 | |
综合类 | 1146篇 |
农作物 | 346篇 |
水产渔业 | 383篇 |
畜牧兽医 | 2150篇 |
园艺 | 231篇 |
植物保护 | 470篇 |
出版年
2023年 | 34篇 |
2022年 | 37篇 |
2021年 | 118篇 |
2020年 | 118篇 |
2019年 | 127篇 |
2018年 | 112篇 |
2017年 | 94篇 |
2016年 | 121篇 |
2015年 | 109篇 |
2014年 | 143篇 |
2013年 | 266篇 |
2012年 | 327篇 |
2011年 | 391篇 |
2010年 | 210篇 |
2009年 | 176篇 |
2008年 | 403篇 |
2007年 | 395篇 |
2006年 | 398篇 |
2005年 | 403篇 |
2004年 | 414篇 |
2003年 | 401篇 |
2002年 | 362篇 |
2001年 | 78篇 |
2000年 | 60篇 |
1999年 | 67篇 |
1998年 | 49篇 |
1997年 | 39篇 |
1996年 | 68篇 |
1995年 | 53篇 |
1994年 | 48篇 |
1993年 | 50篇 |
1992年 | 52篇 |
1991年 | 32篇 |
1990年 | 49篇 |
1989年 | 42篇 |
1988年 | 33篇 |
1987年 | 34篇 |
1986年 | 29篇 |
1985年 | 42篇 |
1984年 | 43篇 |
1983年 | 39篇 |
1982年 | 24篇 |
1981年 | 21篇 |
1980年 | 20篇 |
1979年 | 17篇 |
1978年 | 22篇 |
1977年 | 29篇 |
1976年 | 20篇 |
1975年 | 22篇 |
1974年 | 25篇 |
排序方式: 共有6402条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
46.
47.
Adin DB Maisenbacher HW Ojeda N Fiorello CV Estrada AH Prosek R Citino SB 《American journal of veterinary research》2007,68(2):148-152
OBJECTIVE: To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi). ANIMALS: 20 healthy zebras. PROCEDURES: Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras. RESULTS: Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean +/- SD heart rate of 67 +/- 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras. 相似文献
48.
Response of healthy dogs to infusions of human serum albumin 总被引:1,自引:0,他引:1
Cohn LA Kerl ME Lenox CE Livingston RS Dodam JR 《American journal of veterinary research》2007,68(6):657-663
OBJECTIVE: To evaluate the clinical and immunologic response in healthy dogs to infusions of human serum albumin (HSA). ANIMALS: 9 healthy purpose-bred mixed-breed dogs. PROCEDURES: Each dog was administered a 25% HSA solution once or twice. Various physical examination and laboratory variables were serially evaluated. Antibody against HSA was assayed before and after infusion by use of an ELISA. Intradermal testing was also conducted. A repeated-measures ANOVA or Friedman repeated-measures ANOVA on ranks was used to compare results for the variables. RESULTS: Adverse clinical reactions were observed after the first or second infusion in 3 dogs. Anaphylactoid reactions were observed in 1 of 9 dogs during the first infusion and in 2 of 2 dogs administered a second infusion. Two dogs developed severe edema and urticaria 6 or 7 days after an initial infusion. All dogs developed anti-HSA antibodies. Positive responses for ID tests were observed in 8 of 9 dogs. Short-term increases were detected in blood protein, total bilirubin, and calcium concentrations after HSA infusion. Serum cholesterol concentrations and platelet counts decreased after HSA infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of HSA resulted in profound reactions in 2 of 9 dogs administered a single infusion and in 2 of 2 dogs administered a second infusion. This indicates that there is risk of life-threatening adverse reactions to HSA infusion in healthy dogs. 相似文献
49.
Inoue OJ Freeman DE Wallig MA Clarkson RB 《American journal of veterinary research》2007,68(3):305-312
OBJECTIVE: To determine effects of reactive oxygen metabolites (ROMs), with and without flunixin meglumine, on equine right ventral colon (RVC) in vitro. ANIMALS: 18 healthy horses and ponies. PROCEDURES: In 3 groups of 6 animals each, short-circuit current and conductance were measured in RVC mucosa in Ussing chambers. The 3 groups received physiologic saline (0.9% NaCl) solution, IV, 10 minutes before euthanasia and tissue incubation in Krebs-Ringer-bicarbonate (KRB) solution; flunixin meglumine (1.1 mg/kg, IV) 10 minutes before euthanasia and tissue incubation in KRB solution; or physiologic saline solution, IV, 10 minutes before euthanasia and incubation in KRB solution with 2.7 x 10(5)M flunixin meglumine. Incubation conditions included control (no addition) and ROM systems, including addition of 1 mM xanthine and 80 mU of xanthine oxidase (to produce the superoxide radical), 1 mM H(2)O(2), and 1 mM H(2)O(2) and 0.5 mM ferrous sulfate (to produce the hydroxyl radical). RESULTS: All ROMs that were added or generated significantly increased the short-circuit current except in tissues coincubated with flunixin meglumine, and they induced mild epithelial vacuolation and apoptosis, but did not disrupt the epithelium nor change conductance, lactate dehydrogenase release, or [(3)H]mannitol flux. CONCLUSIONS AND CLINICAL RELEVANCE: Responses to ROMs could be attributed to increased chloride secretion and inhibited neutral NaCl absorption in equine RVC, possibly by stimulating prostaglandin production. The ROMs examined under conditions of this study could play a role in prostaglandin-mediated colonic secretion in horses with enterocolitis without causing direct mucosal injury. 相似文献
50.