全文获取类型
收费全文 | 857篇 |
免费 | 31篇 |
国内免费 | 1篇 |
专业分类
林业 | 19篇 |
农学 | 12篇 |
基础科学 | 2篇 |
84篇 | |
综合类 | 125篇 |
农作物 | 32篇 |
水产渔业 | 30篇 |
畜牧兽医 | 528篇 |
园艺 | 26篇 |
植物保护 | 31篇 |
出版年
2021年 | 5篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 20篇 |
2013年 | 56篇 |
2012年 | 25篇 |
2011年 | 39篇 |
2010年 | 16篇 |
2009年 | 23篇 |
2008年 | 25篇 |
2007年 | 33篇 |
2006年 | 32篇 |
2005年 | 36篇 |
2004年 | 28篇 |
2003年 | 29篇 |
2002年 | 19篇 |
2001年 | 23篇 |
2000年 | 25篇 |
1999年 | 20篇 |
1998年 | 19篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1993年 | 7篇 |
1992年 | 32篇 |
1991年 | 27篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 14篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 12篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 7篇 |
1971年 | 6篇 |
1970年 | 9篇 |
1969年 | 10篇 |
1968年 | 8篇 |
1967年 | 5篇 |
1966年 | 7篇 |
1935年 | 4篇 |
排序方式: 共有889条查询结果,搜索用时 15 毫秒
21.
抗稻瘿蚊品种多抗1的抗性遗传分析及抗性基因定位 总被引:9,自引:1,他引:9
稻瘿蚊是亚洲稻区主要害虫,采用抗虫品种进行防治是最理想的方法。1993~1995年,广东省农科院与国际水稻研究所有关专家紧密合作,对能抗华南4个稻瘿蚊生物型的品种多抗1作进一步抗性遗传分析,确认多抗1对中国稻瘿蚊生物型1和4的抗性受显性单基因控制,这个基因暂定名为GM—6(t)。以多抗1×丰银占1组合的F3代160个家系作基因标记,据DNA库分离个体分析(BSA)原理,用随机扩增多态性DNA(RAPD)标记物OPM6(1.4kb),首次成功地标记了这个抗性基因。随后多态性扩增产物经~(32)p标记,用作探针,检测另一个参考作图群体IR64×Azucena,将这个抗性基因定位在水稻第4条染色体上,位于RG214和RG163两个DNA限制性片段长度多态性(RFLP)标记之间。应用这些分子标记辅助选择有可能不必通过稻瘿蚊的直接筛选,快速准确地选育抗稻瘿蚊品种或进行抗性基因累加。 相似文献
22.
Platt SR Helmick KE Graham J Bennett RA Phillips L Chrisman CL Ginn PE 《Journal of the American Veterinary Medical Association》1999,214(8):1218-20, 1200
Clinical, electromyographic, and pathologic findings characteristic of lead toxicosis were detected in a turkey vulture (Cathartes aura). The bird had generalized lower motor neuron dysfunction that progressed over 5 days. Electromyography revealed diffuse denervation potentials and a presumed decrement in the sciatic-tibial nerve conduction velocity. Histologic examination of peripheral nerves obtained at necropsy revealed changes that could be compatible with lead-induced neuropathy. Lead toxicosis was confirmed by determination of blood lead concentrations. Lead toxicosis causing neurologic disorders in birds has been described. However, this report emphasizes the effects of lead on the peripheral nervous system and demonstrates the use of electromyography for diagnosis of peripheral neuropathy in birds. 相似文献
23.
Transposition of the pectoral muscles for treatment of caudal bifid (cleft) sternum in 2 unrelated African Grey Parrots is described. The birds did not have clinical signs of ventilatory compromise prior to surgery; however, both had cutaneous ulcers over the defects. The pectoral muscles provided a thick pad over the heart, minimizing the risk of trauma to the heart. 相似文献
24.
Hewicker-Trautwein M Carter SD Bennett D Kelly DF 《Veterinary immunology and immunopathology》1999,67(4):341-357
The study describes the distribution of canine leucocyte antigens in synovial membrane biopsies from six dogs with canine rheumatoid arthritis (CRA) and from eight dogs with osteoarthritis (OA) secondary to spontaneous rupture of the cranial cruciate ligament (CCL) (n = 5) or patellar luxation (n = 3). Synovial membranes from five dogs without evidence of joint lesions were used as control tissues. In the subsynovium of dogs with normal joints CD5+, CD4+, CD8+ and alpha beta TCR+ lymphocytes were present only in low numbers. With monoclonal antibody (mAb) to MHC class II antigen, either none or up to 20-30% of synovial lining cells were immunoreactive. Furthermore, scattered MHCII+ stromal cells were seen in the deeper subsynovial layer. In synovial membrane biopsies from dogs with CRA numerous diffusely and perivascularly distributed CD5+ lymphocytes were found in the subsynovium. CD4+ cells outnumbered CD8+ cells and were more numerous in the perivascular areas. In all the CRA cases examined, there were markedly higher numbers of alpha beta TCR+ cells compared with gamma delta TCR+ cells. With mAb to CD21, low numbers of immunoreactive lymphocytes were demonstrated. In all the CRA cases, a marked increase of MHC class II antigen expression was noted. In the majority of samples, 50% or more than 90% of the synovial lining cells were strongly MHC class II+. Throughout the subsynovial layer there were numerous MHC class II+ cells and included those with dendritic morphology and inflammatory mononuclear cells. Furthermore, marked perivascular immunoreactivity for MHC class II antigen was found. In biopsies from dogs with OA, there were markedly lower numbers of subsynovial CD5+, CD4+ and CD8+ lymphocytes. T-cells were mainly diffusely distributed. In three of the eight OA dogs examined, there was an increased percentage of synovial lining cells expressing MHC class II. The majority of OA cases had subsynovial major histocompatibility complex (MHC) class II+ cells with a dendritic morphology. 相似文献
25.
26.
27.
Clements DN Gemmill T Corr SA Bennett D Carmichael S 《The Journal of small animal practice》2003,44(8):355-358
Ten dogs were presented with fractures of the proximal tibial epiphysis and tuberosity. All dogs had a cranioproximal-caudodistal angulation of the tibial plateau. Six dogs had marked caudal displacement of the proximal tibial epiphysis, five of which had also sustained fractures of the proximal fibula. The estimated mean angle of inclination of the tibial plateau of affected limbs was 45.8 +/- 9.6 degrees, which was significantly greater (P<0.0005) than the estimated mean angle of the normal contralateral limb 26.2 +/- 6.6 degrees. The mean angle of inclination of the tibial plateau of dogs with fibular fractures (n=5) was not significantly different from dogs without fibular fractures (n=5) (P>0.25). Five dogs were treated conservatively and five were treated by three different methods of surgical repair. Surgically treated dogs had significantly greater preoperative tibial plateau angles (P<0.05). All dogs regained full limb usage, regardless of the method of treatment chosen. 相似文献
28.
29.
Bennett PF DeNicola DB Bonney P Glickman NW Knapp DW 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(1):100-104
A retrospective study of 43 dogs with anal sac adenocarcinoma (ASAC) was performed to characterize the clinical presentation and response to treatment. Clinical signs at presentation varied considerably, with signs related either to sublumbar nodal metastasis (tenesmus or constipation) or hypercalcemia (polyuria-polydipsia and anorexia) being the most frequent findings. At the time of presentation, 23 (53%) dogs had hypercalcemia and 34 (79%) had metastases, with the regional lymph nodes (31 dogs, 72%) being the most common site of metastasis. A variety of chemotherapeutic agents were administered, with partial remission (PR) recorded in 4 of 13 (31%) dogs treated with cisplatin and in 1 of 3 (33%) dogs treated with carboplatin. The median survival for all dogs was 6 months (range, 2 days-41 months). There was no statistical association between the presence of hypercalcemia and survival, although the power of the study to detect an increase in survival of 3 months was low (.33). We conclude that platinum chemotherapy has antitumor activity in canine apocrine gland carcinoma and that further study of these agents is warranted. 相似文献
30.
Initial results of genomic scans for ovulation rate in a cattle population selected for increased twinning rate 总被引:2,自引:0,他引:2
Kappes SM Bennett GL Keele JW Echternkamp SE Gregory KE Thallman RM 《Journal of animal science》2000,78(12):3053-3059
Genomic scans were conducted with 273 markers on 181 sires from a cattle population selected for increased twinning rate to identify chromosomal regions containing genes that influence ovulation rate. Criteria used for selecting markers were number of alleles, ease of scoring, and relative position within linkage group. Markers were multiplexed or multiple-loaded on the gels to reduce the costs and labor required to obtain genotypic data. This approach reduced the number of gels by 45% when compared with running each marker independently. Male animals selected for the genomic scan sired the majority of the population. A modified interval analysis was used in a granddaughter design to compare effects of each allele within sire for 10 different sire families. The midparent deviation of the son's estimated breeding value for ovulation rate was used as the phenotype. Forty-one potential peaks were identified with a nominal significance level < or = 0.05. The 10 peaks with the highest significance levels (P < 0.02) were selected for further analysis. Markers were genotyped across daughters of the sire where nominal significance was found for each of the 10 peaks. One peak (BTA5, relative position 40 cM) was found to be nominally significant in the daughters. The nominal significance levels were P = 0.01 for the sons (n = 32) and P = 0.02 for the daughters (n = 94) of sire 784403. A combined genomewide significance value (P = 0.07) was calculated that accounted for the 10 analyses with sons and the 10 analyses with daughters. These results strongly suggest that this region contains a gene(s) that is involved in the follicular recruitment and development process. 相似文献