全文获取类型
收费全文 | 1145篇 |
免费 | 50篇 |
专业分类
林业 | 18篇 |
农学 | 11篇 |
基础科学 | 5篇 |
69篇 | |
综合类 | 513篇 |
农作物 | 12篇 |
水产渔业 | 49篇 |
畜牧兽医 | 476篇 |
园艺 | 8篇 |
植物保护 | 34篇 |
出版年
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 23篇 |
2012年 | 19篇 |
2011年 | 43篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 28篇 |
2007年 | 22篇 |
2006年 | 12篇 |
2005年 | 26篇 |
2004年 | 24篇 |
2003年 | 26篇 |
2002年 | 17篇 |
2001年 | 17篇 |
2000年 | 16篇 |
1999年 | 22篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1994年 | 7篇 |
1992年 | 15篇 |
1991年 | 20篇 |
1990年 | 23篇 |
1989年 | 14篇 |
1988年 | 7篇 |
1987年 | 12篇 |
1986年 | 21篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 39篇 |
1979年 | 48篇 |
1978年 | 52篇 |
1977年 | 46篇 |
1976年 | 39篇 |
1975年 | 30篇 |
1974年 | 38篇 |
1973年 | 36篇 |
1972年 | 20篇 |
1971年 | 19篇 |
1970年 | 46篇 |
1969年 | 27篇 |
1968年 | 36篇 |
1967年 | 35篇 |
1966年 | 46篇 |
排序方式: 共有1195条查询结果,搜索用时 15 毫秒
31.
Dabareiner RM Cohen ND Carter GK Nunn S Moyer W 《Journal of the American Veterinary Medical Association》2005,227(10):1646-1650
OBJECTIVE: To identify types of musculoskeletal problems associated with lameness or poor performance in horses used for barrel racing. DESIGN: Retrospective case series. ANIMALS: 118 horses. PROCEDURE: Medical records were reviewed for information on signalment, history, physical and lameness examination findings, diagnostic tests performed, diagnosis, and treatment. RESULTS: Most horses were examined because of lameness (n = 72 [61%]) rather than poor performance (46 [39%]), but owner complaint was not significantly associated with age or body weight of the horse. The most common performance change was refusal or failure to turn properly around the first barrel (19/46 [41%]). The right forelimb (n = 57 [48%]) was most commonly affected, followed by the left forelimb (51 [43%]), the left hind limb (31 [26%]), and the right hind limb (25 [21%]). In 31 horses (26%), both forelimbs were affected, and in 6 (5%), both hind limbs were affected. The most common musculoskeletal problems were forelimb foot pain only (n = 39 [33%]), osteoarthritis of the distal tarsal joints (17 [14%]), suspensory ligament desmitis (15 [13%]), forelimb foot pain with distal tarsal joint osteoarthritis (11 [9%]), and bruised feet (10 [8.5%]). In 81 (69%) horses, the affected joint was treated with intra-articular medications. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in horses used for barrel racing that are examined because of lameness or poor performance, the forelimbs are more likely to be affected than the hind limbs, with forelimb foot pain and osteoarthritis of the distal tarsal joints being the most common underlying abnormalities. 相似文献
32.
Carter LJ 《Science (New York, N.Y.)》1967,155(3760):306-307
33.
34.
Soil redistribution by erosive processes is a serious problem for the potato growing areas of Prince Edward Island. Studies were conducted to evaluate soil loss for three major soil types under two different cropping systems, at catenary sequences with five slope positions, using the 137Cs tracer method. Adjacent forest catenas were sampled to provide baseline 137Cs levels. Soil loss over time (1960–1990) on a specific mass (kg m−2 yr−1) basis was calculated by comparing the 137Cs at the same slope positions for the cropping system and adjacent forest site. The effects of land clearing and long-term cultivation were to increase both the depth and density of the Ap horizon, and decrease the total 137Cs on an area basis, in comparison to the forested sites. The average 137Cs in the forested sites for all three soil types was 3133 Bq m−2. Catena average soil loss across all soil types and slopes, for the 1960–1990 time period, was 21 and 38 Mg ha−1 yr−1 for the pasture and crop rotation (potato) rotations, respectively. Shoulder slope positions tended to have the highest 137Cs loss, which was suggestive of tillage erosion. 相似文献
35.
36.
Brian J. Trumpatori Jennifer E. Carter Jon Hash Gigi S. Davidson Kyle G. Mathews Simon C. Roe B. Duncan X. Lascelles 《Veterinary surgery : VS》2010,39(7):785-796
Objective: To evaluate a technique for midhumeral peripheral nerve blockade in the dog. Study Design: Cadaveric technique development; in vivo placebo‐controlled, prospective crossover study. Animals: Canine cadavers (n=38) and 8 clinically healthy, adult hound dogs. Methods: A technique for peripheral block of the radial, ulnar, musculocutaneous, and median nerves (RUMM block) was evaluated using cadaver limbs. Eight purpose‐bred, research dogs were anesthetized; a RUMM block was performed on each thoracic limb. One limb from each dog randomly received 0.5% bupivacaine and the opposite limb was assigned to receive sterile saline solution as a control. After recovery from anesthesia, skin sensation at selected dermatomes was evaluated for 24 hours using a mechanical stimulus. Weight‐bearing, conscious proprioception, and withdrawal reflex were also evaluated. One month after initial testing, each dog was reanesthetized and each limb received the opposite treatment. Results: Sensory thresholds were significantly increased over baseline measurements when compared with control limbs for all nerves. Complete sensory block was achieved in radial (15/16), ulnar (3/16), musculocutaneous (8/16), and median (11/16) nerves, using a mechanical stimulus of analgesia. Complete simultaneous block of all nerves was only obtained in 1 of 16 limbs. Conclusion: RUMM block resulted in desensitization of the skin in the associated dermatomes for 4–10 hours. Complete sensory block of the dermatomes supplied by the radial nerve was most consistent. Clinical Relevance: RUMM block may be an effective technique to provide adjunctive analgesia for dogs undergoing surgery of the distal aspect of the thoracic limb. 相似文献
37.
Moore GE Burkman KD Carter MN Peterson MR 《Journal of the American Veterinary Medical Association》2001,219(2):209-214
OBJECTIVE: To determine causes of death or reasons for euthanasia in a population of military working dogs. DESIGN: Retrospective study. ANIMALS: 927 military working dogs. PROCEDURE: Records of all military working dogs that died during the period from 1993 to 1996 were evaluated for cause of death or reason for euthanasia by review of necropsy and histopathology reports, death certificates, and daily clinical treatment sheets. A single primary cause of death or euthanasia was determined. RESULTS: Although sexually intact male dogs were more numerous in the study population, castrated male dogs typically lived longer than spayed females or sexually intact males. Leading causes of death or euthanasia (76.3% of all dogs) were appendicular degenerative joint disease, neoplasia, spinal cord disease, nonspecific geriatric decline, and gastric dilatation-volvulus. Compared with German Shepherd Dogs, Belgian Shepherd Dogs were at increased risk for death attributable to neoplasia, behavior, and respiratory tract disease. German Shepherd Dogs had nearly twice the risk for death associated with spinal cord diseases, compared with Belgian Shepherd Dogs. CONCLUSIONS AND CLINICAL RELEVANCE: For most military working dogs, death or euthanasia results from a few diseases commonly associated with advanced age. Some breed differences in risk for these diseases may exist, which clinicians should consider in the procurement and long-term management of these dogs. 相似文献
38.
39.
40.