全文获取类型
收费全文 | 1073篇 |
免费 | 61篇 |
国内免费 | 3篇 |
专业分类
林业 | 29篇 |
农学 | 43篇 |
基础科学 | 5篇 |
127篇 | |
综合类 | 250篇 |
农作物 | 42篇 |
水产渔业 | 46篇 |
畜牧兽医 | 533篇 |
园艺 | 9篇 |
植物保护 | 53篇 |
出版年
2021年 | 9篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 9篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 29篇 |
2012年 | 45篇 |
2011年 | 51篇 |
2010年 | 30篇 |
2009年 | 26篇 |
2008年 | 50篇 |
2007年 | 47篇 |
2006年 | 48篇 |
2005年 | 46篇 |
2004年 | 43篇 |
2003年 | 40篇 |
2002年 | 36篇 |
2001年 | 21篇 |
2000年 | 32篇 |
1999年 | 8篇 |
1998年 | 13篇 |
1996年 | 8篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 32篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 18篇 |
1989年 | 21篇 |
1988年 | 14篇 |
1987年 | 13篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1984年 | 46篇 |
1983年 | 20篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1979年 | 16篇 |
1978年 | 7篇 |
1976年 | 7篇 |
1973年 | 8篇 |
1972年 | 7篇 |
1971年 | 14篇 |
1970年 | 15篇 |
1968年 | 7篇 |
1967年 | 8篇 |
1966年 | 6篇 |
排序方式: 共有1137条查询结果,搜索用时 15 毫秒
41.
42.
43.
Tieghi C Miller WH Scott DW Pasquinelli G 《The Canadian veterinary journal. La revue veterinaire canadienne》2003,44(2):132-136
Medullary trichomalacia is the name proposed for a hair shaft abnormality that was recognized in 6 German shepherd dogs. Affected dogs had multifocal areas of broken hairs, especially on the dorsolateral trunk. Microscopic examination of hair shafts revealed focal areas of loss of architecture, swelling, and apparent softening of the medulla, followed by longitudinal (length-wise) splitting and breakage of the hair shaft. No cause could be found. Affected dogs were otherwise healthy, and apparent spontaneous recovery was the usual outcome. Relapses may occur. 相似文献
44.
Fox AD 《Journal of the American Veterinary Medical Association》2003,223(7):948; author reply 948
45.
46.
Gene Wunderlich 《Agriculture and Human Values》2002,19(1):81-85
The American Country LifeAssociation was heir to Theodore Roosevelt'sCountry Life Commission, which examined thegeneral conditions of farming life in the opencountry, and...its larger problems. In1919, Kenyon Butterfield, a member ofRoosevelt's Commission, met withrepresentatives from 30 states and 25 nationalorganizations to form the American Country LifeAssociation. In that year, Butterfield, ACLA'sfirst president, published a book, TheFarmer and the New Day, whose defining chapterwas The Making of Communities: The CommunityIdea. The ACLA was educator created and led.Solutions to rural problems were seen aseducational matters. But educational philosophywas undergoing scrutiny and new educationalconcepts were arising from the bustling,industrializing, urbanizing times of late19th century. The experimental,unconstrained spirit of the nation at the turnof the century was formalized as pragmatism. Aleading pragmatist and educator of the time wasJohn Dewey, a contemporary of Butterfield.The communitarianism of Butterfield and Deweycarried throughout the life of ACLA in avariety of forms. Even after ACLA ended as anorganization in 1976, the concerns and idealscontinued in successor organizations, and canbe found in environmental, sustainableagriculture, and rural life organizationstoday. This paper traces one of continuingthemes of the ACLA, the community idea as a wayof adding a social dimension to agriculture'seconomic policies and development. The ACLAstory is a metaphor for country life throughmuch of 20th century America. ACLA is alsoa lesson in how organizations come into being,flourish, falter, die, and leave their legaciesto future generations. 相似文献
47.
OBJECTIVE: To evaluate the short-term effects of 4 therapeutic shoeing systems on lameness and voluntary limb-load distribution in horses with chronic laminitis. ANIMALS: 10 horses with chronic laminitis. PROCEDURES: A clinical trial was conducted that used a concurrent control, crossover design to evaluate the relative effectiveness of a standard flat shoe, fullered egg-bar shoe, heart-bar shoe, and modified equine digital support system to alleviate chronic lameness in horses. Therapeutic success was assessed during a 7-day period by use of subjective (Obel grade and clinical score) and objective (force-plate data) evaluations. RESULTS: Comparison of pretreatment and intertreatment control data indicated that disease status of the horses did not change during the course of the study. None of the therapeutic shoeing treatments used resulted in a significant change in severity of lameness. CONCLUSIONS AND CLINICAL RELEVANCE: Results were interpreted to imply that substantial clinical improvement should not be expected during the first 7 days after therapeutic shoeing for the specific shoes tested in this study. On the basis of our results, we hypothesize that when used as the lone indicator of therapeutic success, severity of lameness may not be a valid indicator. 相似文献
48.
Treatment of canine atopic dermatitis with zafirlukast, a leukotriene-receptor antagonist: a single-blinded, placebo-controlled study 总被引:1,自引:0,他引:1 下载免费PDF全文
Senter DA Scott DW Miller WH 《The Canadian veterinary journal. La revue veterinaire canadienne》2002,43(3):203-206
Zafirlukast and placebo were administered orally as individual agents to 20 dogs with atopic dermatitis. The pruritus was effectively reduced by at least 50% in 2/18 (11%) dogs that completed the trial with zafirlukast. Two dogs vomited after administration of the active drug. 相似文献
49.
Eighty-three canine cutaneous mast cell tumors were graded histologically and evaluated immunohistochemically for p53 tumor-suppressor protein expression. An avidin-biotin immunohistochemical protocol incorporated a rabbit polyclonal antibody (CM-1) directed against normal and mutant p53 protein. Positive staining was observed in 44.6% (37/83) of tumors and included 50% (12/24) of grade I (well differentiated) tumors, 46.9% (23/49) of grade II (intermediate differentiation) tumors, and 20% (2/10) of grade III (poorly differentiated) tumors. A statistically significantly higher proportion (P < 0.019) of tumors from the head and neck (83.3%, 10/12), stained positive for p53 than tumors from the thorax, back, abdomen, and axilla (39.4%, 13/33), legs (35.7%, 10/28), or prepuce, scrotal, or inguinal areas (44.4%, 4/9). No statistically significant difference between p53 labeling and histologic grade, breed, or tumor size was present. Survival data were available for 53/83 (63.9%) of dogs. Positive reactivity for p53 was observed in 47% (25/53) of tumors within this group, with 57.9% (11/19) of grade I, 43.3% (13/30) of grade II, and 25% (1/4) of grade III tumors labeled. Mean survival time for the 53 dogs was 12.1 months. The median survival time for dogs with grade III tumors or tumors >5 cm was statistically significantly shorter (P < 0.0001) than for dogs with grades I and II or smaller tumors. Although p53 protein abnormalities may play a role in tumor development or behavior in some canine cutaneous mast cell tumors, immunoreactivity was not associated with lack of tumor differentiation, tumor locations previously shown to demonstrate aggressive biological behavior, breed predisposition, or survival times. 相似文献
50.