首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3346篇
  免费   265篇
  国内免费   4篇
林业   117篇
农学   62篇
基础科学   6篇
  438篇
综合类   639篇
农作物   95篇
水产渔业   181篇
畜牧兽医   1835篇
园艺   87篇
植物保护   155篇
  2024年   6篇
  2023年   43篇
  2022年   41篇
  2021年   126篇
  2020年   121篇
  2019年   122篇
  2018年   108篇
  2017年   118篇
  2016年   92篇
  2015年   98篇
  2014年   122篇
  2013年   151篇
  2012年   260篇
  2011年   306篇
  2010年   145篇
  2009年   120篇
  2008年   235篇
  2007年   235篇
  2006年   200篇
  2005年   216篇
  2004年   161篇
  2003年   179篇
  2002年   152篇
  2001年   22篇
  2000年   11篇
  1999年   12篇
  1998年   26篇
  1997年   15篇
  1996年   11篇
  1995年   11篇
  1994年   7篇
  1993年   11篇
  1992年   5篇
  1991年   8篇
  1990年   10篇
  1989年   7篇
  1987年   4篇
  1986年   6篇
  1985年   9篇
  1984年   5篇
  1981年   5篇
  1980年   5篇
  1977年   8篇
  1976年   5篇
  1975年   3篇
  1974年   3篇
  1972年   3篇
  1965年   3篇
  1963年   3篇
  1956年   3篇
排序方式: 共有3615条查询结果,搜索用时 31 毫秒
81.
82.
83.
84.
Sepsis is a frequent source of morbidity and mortality in critically ill patients. The goal of this case control study was to measure hemostatic changes in dogs with naturally occurring sepsis. Blood was collected within 24 hours of admission from 20 dogs that fulfilled the criteria for sepsis. Sepsis was defined as histologic or microbiological confirmation of infection and 2 or more of the following criteria: hypo- or hyperthermia, tachycardia, tachypnea, or leukopenia, leukocytosis, or > 3% bands. Culture and sensitivities were performed on appropriate samples from all septic dogs. Twenty-eight control dogs were enrolled on the basis of normal results of physical examination, CBC, serum biochemistry, and coagulation profile. Plasma samples were analyzed for prothrombin time (PT), partial thromboplastin time (PTT), fibrin(ogen) degradation products (FDP), D-dimer (DD) concentrations, antithrombin (AT) activity, and protein C (PC) activity. Data were compared between groups by chi-square or independent t-tests. PC (P < .001) and AT (P < .001) activities were significantly lower in dogs with sepsis compared to controls. Dogs with sepsis had significantly higher PT (P = .007), PTT (P = .005), D-dimer (P = .005), and FDP (P = .001) compared to controls. Platelet counts were not significantly different between groups. Ten of the 20 septic dogs (50%) died, but no association was identified between any of the measured variables and outcome. These findings are consistent with previous studies in animals with experimentally induced disease and in clinical studies of humans. On the basis of these results, further investigation of the role of AT and PC in canine sepsis is warranted.  相似文献   
85.
Thirty-eight dogs with orthopedic disorders received etodolac, an NSAID, at 10.0 to 13.3 mg/kg PO once daily for 14 to 19 days. Mean total thyroxine (T4), free thyroxine (fT4), and canine thyrotropin (cTSH) values before and after etodolac administration were compared using paired t-tests. A significant (P <.05) decrease in T4 values occurred after etodolac administration with 21% of these values falling below the reference range. A significant (P <.05) increase in cTSH following etodolac administration, but none of the values was above the reference range. No significant changes occurred in mean fT4 values; however, 10% of the values fell below the reference range. In conclusion, T4 and fT4 test results should be interpreted with caution in dogs receiving etodolac.  相似文献   
86.
87.
The diagnostic test for Tritrichomonas foetus in bulls is microscopic examination of cultured preputial samples. Trichomonads other than T. foetus can be present in a preputial sample. Both a staining technique and a polymerase chain reaction assay were useful in differentiating between T. foetus and another trichomonad observed in samples from virgin bulls.  相似文献   
88.
89.
Clostridium difficile and Clostridium perfringens are anaerobic, Gram-positive bacilli that are common causes of enteritis and enterotoxemias in both domestic animals and humans. Both organisms have been associated with acute and chronic large and small bowel diarrhea, and acute hemorrhagic diarrheal syndrome in the dog. The objective of this study was to determine the in vitro antimicrobial susceptibilities of canine C. difficile and C. perfringens isolates in an effort to optimize antimicrobial therapy for dogs with clostridial-associated diarrhea. The minimum inhibitory concentrations (MIC) of antibiotics recommended for treating C. difficile (metronidazole, vancomycin) and C. perfringens-associated diarrhea in the dog (ampicillin, erythromycin, metronidazole, tetracycline, tylosin) were determined for 70 canine fecal C. difficile isolates and 131 C. perfringens isolates. All C. difficile isolates tested had an MIC of or=256 microg/ml for both erythromycin and tylosin. A third C. perfringens isolate had an MIC of 32 microg/ml for metronidazole. Based on the results of this study, ampicillin, erythromycin, metronidazole, and tylosin appear to be effective antibiotics for the treatment of C. perfringens-associated diarrhea, although resistant strains do exist. However, because there is limited information regarding breakpoints for veterinary anaerobes, and because intestinal concentrations are not known, in vitro results should be interpreted with caution.  相似文献   
90.
Two dogs were emaciated and hypoalbuminemic due to protein-losing enteropathy associated with a severe, focal, mucoid, cryptal ectasia of the duodenum and marked villus atrophy. In one case, diseased portions of the duodenum were obvious endoscopically and were limited to discrete, focal areas in the small intestine, with apparently more undiseased tissue than diseased tissue being present. The signs and lesions in one dog resolved after initiating combination dietary and pharmacological therapy.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号