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   102篇
  免费   12篇
林业   13篇
农学   6篇
  25篇
综合类   8篇
农作物   7篇
水产渔业   5篇
畜牧兽医   44篇
园艺   1篇
植物保护   5篇
  2021年   1篇
  2020年   4篇
  2019年   2篇
  2018年   6篇
  2017年   9篇
  2016年   4篇
  2015年   1篇
  2014年   1篇
  2013年   8篇
  2012年   2篇
  2011年   5篇
  2010年   5篇
  2009年   5篇
  2008年   11篇
  2007年   1篇
  2006年   7篇
  2005年   3篇
  2004年   3篇
  2003年   4篇
  2002年   2篇
  2000年   1篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1996年   6篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   6篇
  1989年   3篇
  1983年   1篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1966年   1篇
排序方式: 共有114条查询结果,搜索用时 31 毫秒
61.
The low molecular weight glutenin subunits (LMW-GS) are major components of the glutenin polymers which determine the elastomeric properties of wheat (Triticum aestivum L.) gluten and dough. They comprise a complex mixture of components and have proved to be difficult to purify for detailed characterisation. The mature LMW subunit proteins comprise two structural domains, with one domain consisting of repeated sequences based on short peptide motifs. DNA sequences encoding this domain and a whole subunit were expressed in Escherichia coli and the recombinant proteins purified. Detailed comparisons by spectroscopy (CD, FT-IR) and dynamic light scattering indicated that the repetitive and non-repetitive domains of the proteins formed different structures with the former having an extended conformation with an equilibrium between poly-L-proline II-like structure and type II' β-turns, and the latter a more compact globular structure rich in α-helix. Although the structures of these two domains appear to form independently, dynamic light scattering of the whole subunit dissolved in trifluoroethanol (TFE) suggested that they interact, leading to a more compact conformation. These observations may have relevance to the role of the LMW-GS in gluten structure and functionality.  相似文献   
62.
Lysozyme is a low-molecular-weight protein with antimicrobial properties. An experiment was conducted to investigate the response of piglets receiving a water-soluble lysozyme supplement [Entegard (EG), Neova Technologies Inc., Abbotsford, British Columbia, Canada; 4,000 lysozyme units/mg] after oral challenge with enterotoxigenic Escherichia coli (ETEC). A total of 36 individually housed weanling pigs were randomly allotted to 1 of the 4 treatments, with 9 replicates per treatment. Treatments were a control (CONT, no additive), antibiotic (AB; 2.5 g/kg of feed of antibiotic with chlortetracycline, sulfamethazine, and penicillin), and EG delivered in the drinking water at concentrations of 0.1% (EG1) and 0.2% (EG2). All pigs received a basal diet similar in composition and nutrients, except for pigs receiving the AB diet, which had an added antibiotic. Pigs were acclimated to treatments for a 7-d period to monitor growth performance. On d 8, blood samples were collected from each pig to obtain serum, and each pig was gavaged with 6 mL (2 × 10(9) cfu/mL) of ETEC solution. Pigs were monitored for another 7 d to assess incidences of diarrhea and growth performance, and then all pigs were killed to obtain intestinal tissue and digesta samples. Treatments did not influence growth performance throughout the study. Greater ETEC counts were observed in the ileal mucosal scrapings (P = 0.001) and colonic digesta (P = 0.025) of pigs in the CONT group compared with pigs in the AB and EG1 groups. Pigs receiving AB and EG1 had greater (P < 0.05) small intestinal weights and ileal villus heights than pigs receiving CONT; however, the ileal villus height-to-crypt depth ratio was greater in pigs fed the AB diet (1.69) compared with those fed the CONT diet (1.34), whereas pigs receiving EG1 were intermediate. Pigs in the EG1 group showed greater (P < 0.001) serum tumor necrosis factor α and IL-6 concentrations before ETEC challenge; however, at 7 d postchallenge, pigs receiving EG2 showed the least (P < 0.05) circulating tumor necrosis factor α and IL-6 concentrations. Overall, better intestinal growth and development, as well as decreased ETEC counts on the intestinal mucosa and serum proinflammatory cytokines, suggest that EG can maintain gut health and function in piglets commensurate with antibiotics. However, it is noteworthy that at the largest dose tested, EG seemed to have a dramatic effect on proinflammatory cytokines but had a minimal or no effect on the other response criteria.  相似文献   
63.
Antioxidants are known to prevent the reactive oxygen species (ROS)‐mediated peroxidative damage to the membrane lipids during hypothermic storage of mammalian spermatozoa. We hypothesized here that ROS also affect the lipid–protein interactions, thereby diminishing the membrane's integrity and proteins' anchorage to the bilayer. Antioxidants prevent these damages by scavenging the ROS. Ejaculates from Patanwadi rams were pooled after subjective evaluation and centrifuged using Percoll®. Sperm pellet was resuspended in soya lecithin–Tris–fructose diluent (400 × 106 cells/ml) containing either antioxidants (100 IU/ml catalase + 10 mM reduced glutathione) or no antioxidant. Aliquots were chilled to 5°C in a cabinet and stored in a refrigerator at 3–5°C for 72 hr. Sperm motility, viability, lipid peroxidation (LPO) and hypo‐osmotic swelling test (HOST) were performed at 0, 24, 48 and 72 hr. Sperm proteins extracted with 0.5% Triton X‐100 were resolved by SDS‐PAGE and quantified using Quantity One software (Bio‐Rad, USA). The rapid motility, linearity and straight‐line velocity (VSL) were found significantly (p < .05) higher in the antioxidant‐treated group compared to the control at 48 hr of storage. Sperm viability was found comparable between the groups. Higher HOST response and lower LPO were found in the antioxidant‐treated sample compared to the control both at 48 and at 72 hr. Overall, the proteins P1 (106.09 kDa), P2 (87.00 kDa) and P4 (51.14 kDa) were lower (p < .05) in the sperm extract of antioxidant‐treated group compared to the control. The content of P4 (51.14 kDa) in sperm extract was found to increase (p < .05) earlier (48 vs. 72 hr) in the control group compared to the antioxidant‐treated group. Altogether, the results suggested that antioxidants reduced LPO in spermatozoa, resulting in higher sperm motility, plasma membrane integrity and protection of proteins' anchorage to the plasma membrane at 48 and 72 hr of storage.  相似文献   
64.
This study compared artificial insemination pregnancy rate (AI‐PR) between 14‐day CIDR‐GnRH‐PGF2α‐GnRH and CIDR‐PGF2α‐GnRH synchronization protocol with two fixed AI times (56 or 72 hr after PGF2α). On day 0, heifers (= 1311) from nine locations assigned body condition score (BCS: 1, emaciated; 9, obese), reproductive tract score (RTS: 1, immature, acyclic; 5, mature, cyclic) and temperament score (0, calm; and 1, excited) and fitted with a controlled internal drug release (CIDR, 1.38 g of progesterone) insert for 14 days. Within herd, heifers were randomly assigned either to no‐GnRH group (= 635) or to GnRH group (= 676), and heifers in GnRH group received 100 μg of GnRH (gonadorelin hydrochloride, IM) on day 23. All heifers received 25 mg of PGF2α (dinoprost, IM) on day 30 and oestrous detection aids at the same time. Heifers were observed for oestrus thrice daily until AI. Within GnRH groups, heifers were randomly assigned to either AI‐56 or AI‐72 groups. Heifers in AI‐56 group (= 667) were inseminated at 56 hr (day 32 PM), and heifers in AI‐72 group (= 644) were inseminated at 72 hr (day 33 AM) after PGF2α administration. All heifers were given 100 μg of GnRH concurrently at the time AI. Controlling for BCS (< .05), RTS (< .05), oestrous expression (< .001), temperament (< .001) and GnRH treatment by time of insemination (< .001), the AI‐PR differed between GnRH treatment [GnRH (Yes – 60.9% (412/676) vs. No – 55.1% (350/635); < .05)] and insemination time [AI‐56 – 54.6% (364/667) vs. AI‐72 – 61.8% (398/644); (< .01)] groups. The GnRH treatment by AI time interaction influenced AI‐PR (GnRH56 – 61.0% (208/341); GnRH72 – 60.9% (204/335); No‐GnRH56 – 47.9% (156/326); No‐GnRH72 – 62.8% (194/309); < .001). In conclusion, 14‐day CIDR synchronization protocol for FTAI required inclusion of GnRH on day 23 if inseminations were to be performed at 56 hr after PGF2α in order to achieve greater AI‐PR.  相似文献   
65.
The genetic diversity in genus Prunus is mainly confined to temperate regions of Himalaya and to a lesser extent in the sub-montane and hilly regions of peninsular India. The cultivated and wild species of Prunus have tremendous potential for improvement and utilization. This paper includes the genetic resources of cultivated and wild useful species of Prunus in India with emphasis on their distribution, potential traits/ useful characteristics and utilization. The information on potential genetic resources of Prunus would be helpful in collection, evaluation, conservation and utilization of species.  相似文献   
66.
Aquilaria malaccensis, categorized by IUCN as globally vulnerable, is in high demand in the Middle East and Asian markets for its unique resinous agarwood. In August 2015, symptoms of dieback were observed on A. malaccensis trees planted in the Medicinal and Aromatic Plant Garden, Panbari, Golaghat of the Assam Forest Department. The entire crowns of 70 trees showed complete leaf loss and severe dieback. Rotting at the collar region and of roots was also observed. Isolation from the infected roots consistently yielded Fusarium equiseti identified following standard laboratory procedures and analysis of the internal transcribed spacer (ITS) sequence of the ribosomal DNA. Symptoms of wilt, dieback and root rot were observed on 5‐month‐old Aquilaria seedlings 25 days after inoculation with the isolated fungus. This paper is the first report of F. equiseti causing wilt and dieback of A. malaccensis.  相似文献   
67.
68.
In arid conditions in India,Ganoderma lucidum (Leyss: Fr.) P. Karsten was found to cause root rot diseases in jojoba (Simmondsia chinensis (Link) Schneider) plants. In the rainy season, 10–15-year-old jojoba plants growing in the proximity of aGanoderma-infectedAcacia tortilis tree, developed disease symptoms. Twigs of affected plants started drying from the top of the branch; leaves turned yellowish brown and finally abscissed; plants dried up within 1 to 3 months. Basidiocarps developed from decaying roots near the collar region and produced colored stalks and fruiting caps. Pathogenicity of the fungus was established by keeping the infected root segments in direct contact with roots of healthy jojoba plants. Root rot symptoms were expressed within 5 months in inoculated plants subjected to moisture stress.  相似文献   
69.
70.
A protocol has been developed for inoculation of rust disease in Dalbergia sissoo using urediniospores of Maravilia achroa. This is the first time that disease symptoms caused by M. achroa were artificially produced. The method has been successfully employed for screening 15 clones of D. sissoo against rust disease. Clone S‐167 was the most resistant remaining free from infection. Clones S‐57, S‐106 and S‐124 were also resistant. Clones S‐19, S‐24 and S‐89 were susceptible.  相似文献   
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