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   559篇
  免费   16篇
林业   17篇
农学   13篇
  87篇
综合类   87篇
农作物   8篇
水产渔业   18篇
畜牧兽医   310篇
园艺   12篇
植物保护   23篇
  2021年   6篇
  2020年   5篇
  2019年   9篇
  2018年   6篇
  2017年   6篇
  2015年   5篇
  2014年   7篇
  2013年   8篇
  2012年   24篇
  2011年   23篇
  2010年   11篇
  2009年   18篇
  2008年   20篇
  2007年   29篇
  2006年   28篇
  2005年   22篇
  2004年   21篇
  2003年   18篇
  2002年   14篇
  2001年   15篇
  2000年   22篇
  1999年   15篇
  1998年   6篇
  1997年   6篇
  1996年   4篇
  1995年   7篇
  1994年   4篇
  1993年   5篇
  1992年   10篇
  1991年   21篇
  1990年   15篇
  1989年   9篇
  1988年   5篇
  1987年   11篇
  1986年   11篇
  1985年   4篇
  1984年   13篇
  1980年   4篇
  1979年   9篇
  1978年   6篇
  1977年   3篇
  1975年   6篇
  1974年   9篇
  1973年   4篇
  1972年   5篇
  1971年   6篇
  1970年   8篇
  1969年   7篇
  1968年   4篇
  1967年   4篇
排序方式: 共有575条查询结果,搜索用时 0 毫秒
71.
72.
One hundred eighty-five dogs with histologically confirmed, measurable malignant tumors were used in a study to determine the toxicity of the anthracycline antitumor antibiotic, doxorubicin, which was administered once or twice (at a 21-day interval) at the rate of 30 mg/m2 of body surface area, iv. During this study, 7 dogs died as a direct result of doxorubicin-induced toxicosis and 16 died as a direct result of the malignant neoplastic disease. Each dog was evaluated for signs of toxicosis for 3 weeks after the last dose was administered (15 dogs received 1 dose, 170 dogs received 2 doses) or until the dog died, whichever came first. The most common signs of toxicosis were vomiting, diarrhea, colitis, anorexia, and pruritus. The probability of doxorubicin-induced toxicosis decreased significantly (P less than 0.0001) in inverse relationship to body weight. Dogs with signs of toxicosis during the 21-day interval from administration of the first dose of doxorubicin were 17.2 times (P less than 0.01; 95% confidence interval; 5.5, 54.2) more likely to develop signs of toxicosis during the 21-day interval from the second dose of doxorubicin. The performance status of each dog was evaluated using a modified Karnofsky performance scheme; the only time the performance status was adversely affected to a significant extent by doxorubicin-induced toxicosis was during the 21-day period, starting with the second dose (P less than 0.0001).  相似文献   
73.
SUMMARY A case of vaginal prolapse in a South Australian Sea Lion is described. Conservative treatment proved unsuccessful, and an ovariohysterectomy was performed. Problems concerning anaesthesia, surgery and post-operative management of this marine species are discussed.  相似文献   
74.
75.
The course of vesicular stomatitis in cattle was investigated in 2 dairy herds (A and B) located in the southern San Joaquin Valley of California. Cattle were examined and specimens were obtained for virus isolation and for serologic survey for one year after an epizootic in December 1982. All 33 lactating cows selected for study had oral lesions, but only 19 (58%) were drooling or frothing around the mouth. Lesions on feet and teats were not observed. The healing time (longer than has been reported previously) for oral lesions ranged from 34 to 59 days. The mean serum neutralizing antibody titer for all cows tested in both herds 21 days after clinical signs were first observed was greater than 1:512. The mean titer decreased in the first 11 months after the epizootic, but remained greater than 1:128, and then increased during December 1983. Vesicular stomatitis virus/New Jersey strain was not isolated from 239 blood samples, 235 swab specimens of oral cavities, 38 swab specimens of oral epithelium, 206 urine specimens, or 232 fecal specimens collected from cows; however, it was isolated from tongue epithelium of 3 cows at 1, 4, and 21 days after signs of frothing were first noticed. For 20 lactating cows brought into dairy A during the epizootic, a mean time of 8.9 days elapsed between time of entry and appearance of clinical signs of vesicular stomatitis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
76.
77.
Fifteen flocks of replacement pullets affected with hysteria were treated with metoserpate hydrochloride via the drinking water after water was withheld for an adequate period. The dose was 4 mg/kg body weight (BW) on day 1, and 2 mg/kg BW on days 5 and 9. Metoserpate hydrochloride proved effective and safe for treating clinical cases of hysteria in replacement pullets.  相似文献   
78.
Twenty-six, ten-week-old mink were infected by force feeding by pipette 2 ml of a tissue suspension containing a Wisconsin strain of mink enteritis virus. Four days later, diarrhea and partial or complete loss of appetite developed simultaneously in all of the animals. Squinting and occasional vomiting were also observed. By the sixth day after inoculation, all of the mink were anorectic and weak. Anorexia persisted for 48 to 96 hours. Diarrhea and vomiting continued until the eighth to ninth day after exposure. For the first two days after the appearance of diarrhea, the feces contained large quantities of mucus and intestinal casts were seen frequently in the droppings. Thereafter, the feces consisted mostly of yellowish green, watery fluid and contained no casts. Some of the animals died on the eighth day after infection. Those which survived were severely dehydrated and debilitated, but resumed eating and achieved complete clinical recovery within the next five to six days.

Leukopenia, i.e., total leukocyte count of less than 5,000 cells per mm3 of blood, was found in seven of nine mink examined during the height of the disease. Leukopenic animals were deficient in both lymphocytes and neutrophils.

  相似文献   
79.
Angiography of the crus penis in the ram and buck during erection   总被引:1,自引:0,他引:1  
Serial angiography was used to determine blood flow patterns to the penis of rams and bucks. Animals were anesthetized and the internal pudendal artery was catheterized so that contrast medium could be injected toward the crus penis area. By comparing vascular patterns of the ram and buck during erection, it was found that flow patterns of the corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP) were similar for both species. Contraction of the ischiocavernosus muscles occluded the arterial inflow and venous outflow to the CCP, making it a closed system during peak erection. However, during erection, the contrast medium continued to flow into the CSP, showing that it is not a closed system. In the vasodilatation phase, the CSP usually filled before and more intensely than did the CCP.  相似文献   
80.
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