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   486篇
  免费   16篇
  国内免费   2篇
林业   75篇
农学   19篇
  50篇
综合类   24篇
农作物   17篇
水产渔业   65篇
畜牧兽医   213篇
园艺   8篇
植物保护   33篇
  2023年   3篇
  2022年   14篇
  2021年   21篇
  2020年   9篇
  2019年   12篇
  2018年   10篇
  2017年   11篇
  2016年   17篇
  2015年   11篇
  2014年   18篇
  2013年   22篇
  2012年   22篇
  2011年   33篇
  2010年   13篇
  2009年   15篇
  2008年   10篇
  2007年   24篇
  2006年   30篇
  2005年   37篇
  2004年   29篇
  2003年   25篇
  2002年   17篇
  2001年   11篇
  2000年   7篇
  1999年   5篇
  1998年   6篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1994年   2篇
  1993年   3篇
  1992年   7篇
  1991年   7篇
  1990年   7篇
  1989年   6篇
  1988年   4篇
  1987年   4篇
  1986年   6篇
  1985年   4篇
  1984年   6篇
  1982年   1篇
  1981年   1篇
  1980年   3篇
  1979年   4篇
  1978年   1篇
  1976年   1篇
  1969年   1篇
  1967年   1篇
排序方式: 共有504条查询结果,搜索用时 15 毫秒
1.
2.
A 2-year-old domestic shorthair cat was presented to us with decreased activity and anorexia. Hematologic findings revealed a mild non-regenerative anemia, thrombocytopenia, and leukocytosis with an increase in blast cells. Bone marrow aspirates also revealed a marked increase of blasts. The blastic cells were shown to be positive for peroxidase. Acute myeloblastic leukemia without maturation (M1) was diagnosed according to the FAB classification. Chemotherapy was initiated with cyclophosphamide, vincristine, prednisolone, and cytosine arabinoside. The cat responded partially. In total, the cats were given 7 blood transfusions. The cat died 14 weeks after first being presented to us.  相似文献   
3.
To facilitate the control of progressive atrophic rhinitis (PAR) of swine caused by toxigenic Pasteurella multocida, an enzyme-linked immunosorbent assay (ELISA) and a serum neutralization test (NT) have recently been developed to detect antibodies against the P. multocida dermonecrotic toxin (PmDNT). However, the NT is a cumbersome and time-consuming technique. To overcome these drawbacks, we developed an indirect ELISA, using recombinant PmDNT expressed in Escherichia coli, for the detection of antibodies to PmDNT in serum samples from pigs. The practical usefulness of this ELISA was compared with the NT using serum samples obtained from experimentally infected and naturally infected pigs. In the pigs experimentally inoculated with vaccine including PmDNT toxoid, the ELISA and neutralization antibodies were detected at almost the same time, and a good correlation was demonstrated between both tests (P<0.01, R(2)=0.807). Therefore, the ELISA can be used to evaluate the immune reaction of pigs after vaccination with P. multocida toxoid. In a survey conducted on a field herd with a history of clinical AR, the seropositivity by ELISA in pigs of age 4.5-6 months was increased even though the NT was negative, and the correlation was low between the results obtained with the two tests (P<0.01, R(2)=0.38). Therefore, the results indicated that this ELISA might be a useful alternative to the NT currently used to detect the antibody to PmDNT after vaccination or infection with P. multocida.  相似文献   
4.
5.
In many disaster settings, top‐down responses emphasise ‘expert‐led’ solutions that often involve relocating disaster‐affected communities. While the intention might be to move people from harm's way and facilitate recovery, failure to attend to local pre‐disaster circumstances as well as the interplay between power, resilience and vulnerability within and around affected communities often sees resettlement reconfigure as displacement or disconnection. This oversight may even usher in a new phase of dispossession and disadvantage for marginalised groups (particularly in colonial settings). This paper explores experiences in Australia, Japan and Taiwan to reflect on what issues of local sociality, local culture and local resilience need to be attended to in framing ‘better’ disaster responses.  相似文献   
6.
γ-Oryzanol is a main oleophilic component in rice bran oil and has been well recognized as a good dietary supplement for human health, as well as having uses in industrial materials. japonica-type rice cultivars generally showed significantly higher contents of total γ-oryzanol in brown rice compared with indica-type cultivars, although within-group variation was significant. The objective of this study was to explore quantitative trait loci (QTLs) responsible for the difference in the γ-oryzanol content between japonica-type and indica-type rice cultivars, using recombinant inbred lines (RILs), backcross inbred lines (BILs), and corresponding chromosome segment substitution lines (CSSLs) derived from crosses between japonica-type and indica-type. Results from RILs and BILs showed that eight QTLs were detected with R2 from .09 to .16. Nine candidate regions for QTL were also suggested from corresponding CSSLs. These QTLs from RILs and BILs and the candidate regions from CSSLs were not overlapped, although one QTLs was mapped near the boundaries of the respective candidate region. At four QTLs and three candidate regions, alleles or segments from japonica-type caused higher contents than those from indica-type. On the other hand, at the other four QTLs and six candidate regions, alleles or segments from indica-type caused higher contents than those from japonica-type, which is a reverse result to the parental differences. This result strongly suggested that alleles with increasing effects on γ-oryzanol content could be accumulated not only from japonica-type but also from indica-type, leading to a potential for increase in γ-oryzanol content in future breeding programs.  相似文献   
7.
A novel range of trimethylstanniomethyl ethers of well known pyrethroid alcohols were synthesised, and their insecticidal activities and modes of action as insecticides were investigated. Among them, ethers from three types of alcohol (3-phenoxybenzyl, 4-fluoro-3-phenoxybenzyl and 6-phenoxy-2-pyridylmethyl) showed remarkable insecticidal activities against rice stem borers, houseflies and German cockroaches. According to electrophysiological studies on the abdominal nerve cords of German cockroaches, trimethylstanniomethyl 6-phenoxy-2-pyridylmethyl ether induced a rapid decline in spontaneous firing similar to that from tetramethrin. However, insecticidal trimethyltin chloride caused an entirely different response. These observations suggest that the present tin ether derivatives resemble pyrethroids, rather than the insecticidal tin compounds known so far.  相似文献   
8.
Carnosine, and its derivative anserine, are known to function as anti‐oxidants and putative neurotransmitters. They are especially rich in the breast muscle (Musculus pectoralis superficialis, MPS) of chickens. To clarify whether the concentrations of carnosine and anserine are altered by dietary management, the effect of oral administration of their constituent, β‐alanine (β‐Ala), was determined in the MPS and brains of chickens. Birds were orally administered β‐Ala (22 mmol/kg) twice a day for five consecutive days (from 2 to 6 days old). In the MPS, carnosine was increased by β‐Ala, whereas anserine and taurine were decreased. The concentrations of other free amino acids in the MPS were also modified by β‐Ala. In the brain, the oral administration of β‐Ala increased anserine and carnosine and decreased taurine, but caused no changes to other free amino acid concentrations. These results suggest that orally administered β‐Ala increases carnosine concentrations in both the MPS and brains of chickens. However, the effects of β‐Ala on other concentrations differ depending on the tissues.  相似文献   
9.
10.
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