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   425篇
  免费   35篇
  国内免费   2篇
林业   19篇
农学   12篇
基础科学   3篇
  107篇
综合类   22篇
农作物   19篇
水产渔业   33篇
畜牧兽医   203篇
园艺   17篇
植物保护   27篇
  2023年   2篇
  2022年   5篇
  2021年   16篇
  2020年   23篇
  2019年   29篇
  2018年   16篇
  2017年   14篇
  2016年   18篇
  2015年   10篇
  2014年   17篇
  2013年   22篇
  2012年   41篇
  2011年   46篇
  2010年   18篇
  2009年   19篇
  2008年   27篇
  2007年   29篇
  2006年   24篇
  2005年   21篇
  2004年   16篇
  2003年   14篇
  2002年   12篇
  2001年   5篇
  2000年   1篇
  1999年   6篇
  1997年   4篇
  1993年   1篇
  1988年   1篇
  1975年   1篇
  1973年   1篇
  1972年   2篇
  1968年   1篇
排序方式: 共有462条查询结果,搜索用时 359 毫秒
1.
A UV exclusion experiment was conducted on durum wheat (Triticum durum Desf. var. Claudio) grown in pots. Plants were grown under three different radiative treatments in greenhouses covered with plastic filters: Teflon, transparent to the entire region of natural UV‐visible sunlight (TEF); polyester, transparent above 312 nm (MYL, excluding UVB) and Lee, transparent above 400 nm (LEE, excluding both UVA and UVB). Analyses have been carried out to determine the concentration of photosynthetic pigments in leaves, UV‐absorbing compounds, nitrogen and carbon in leaves, culms and spikes and proteins and gluten in grains. In particular, plants grown under UV exclusion showed a reduction in protein and dry gluten content (consequently without variation in the ratio dry gluten/protein), but at the same time, a significant increase of gluten index, which is a parameter to define the quality of gluten, was observed. The results highlighted the influence played by UV radiation on some biochemical parameters, mainly UV‐absorbing compounds, leaf nitrogen and grain protein characteristics of durum wheat cultivated under Mediterranean conditions. In particular, natural level of UV in the Mediterranean improves the characteristics of durum wheat flour important for pasta production (high dry gluten level), while the UV exclusion could improve characteristics of flour important for bread production (high gluten index).  相似文献   
2.
The aim of this study was to identify differentially expressed genes (DEG) in the Longissimus thoracis muscle of Nelore cattle related to fatty acid (FA) profile through RNA sequencing and principal component analysis (PCA). Two groups of 10 animals each were selected containing PC1 and PC2 extreme DEG values (HIGH × LOW) for each FA group. The intramuscular fat (IMF) was compared between cluster groups by ANOVA, and only the sum of monounsaturated FA (MUFA) and ω3 showed significant differences (p < .05). Interestingly, the highest percentage (95%) of phenotypic variation explained by the sum of the first two PC was observed for ω3, which also displayed the lowest number of DEG (n = 1). The lowest percentage (59%) was observed for MUFA, which also revealed the largest number of DEG (n = 66). Since only MUFA and ω3 exhibited significant differences between cluster groups, we can conclude that the differences observed for the remaining groups are not due to the percentage of IMF. Several genes that have been previously associated with meat quality and FA traits were identified as DEG in this study. The functional analysis revealed one KEGG pathway and eight GO terms as significant (p < .05), in which we highlighted the purine metabolism, glycolytic process, adenosine triphosphate binding and bone development. These results strongly contribute to the knowledge of the biological mechanisms involved in meat FA profile of Nelore cattle.  相似文献   
3.
Thymoma is a relatively common tumor in rabbits. Treatment with surgery, radiation therapy, and chemotherapy alone or in combination has been reported with varying outcomes. Stereotactic volumetric modulated arc radiotherapy delivered in a hypofractionated manner allows high doses of radiation to be delivered to the target volume while allowing sparing of adjacent critical structures. This therapy is ideally suited for thymomas in rabbits given their size, the difficulty of multiple anesthesia episodes and the complexity of the radiotherapy plans required due to the tumor's proximity to the heart, lungs, and mediastinal structures. Fifteen rabbits with thymoma were prospectively recruited for this observational, single institution, single arm clinical study. All rabbits were imaged with both computed tomography (CT) and magnetic resonance imaging (MRI). A total dose of 40 Gy in six fractions was delivered using a single arc over an 11‐day period with repeat CT simulation done every other fraction for adaptive planning. Follow‐up evaluation was done through repeat CT and MRI imaging and revealed complete responses using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Two rabbits had died at 618 and 718 days, 10 were alive and three were lost to follow‐up. Observed acute and late effects were graded according to the Veterinary Radiation Therapy Oncology Group (VRTOG) criteria and were found to be minimal.  相似文献   
4.
5.
Several sentinel lymph node (SLN) mapping techniques, to detect nodal metastasis in canine tumours have been investigated in the last 10 years in veterinary oncology. The purpose of this prospective study was to describe a reliable, quick, and inexpensive technique for SLN mapping in canine patients affected by cutaneous and subcutaneous mast cell tumours (MCT). Eighty dogs were enrolled in this study for a total of 138 cytologically diagnosed MCTs. Sentinel lymph node mapping was performed by injecting iomeprole peritumorally followed by serial radiographs at 1, 3, 6 and 9-min post injection. A total of 168 SLNs were detected, 90% at first radiograph, 1 min after the peritumoral iomeprole injection, while in the rest of the cases SLN was identified at 3 min. Sentinel lymph nodes detected by the preoperative radiographic indirect lymphography with iomeprole (PRILI) differed from regional lymph nodes in 57% of cases. The PRILI technique detected simultaneously multiple SLNs in the 26% of cases and multiple lymph centers in the 31% of MCTs. To allow the surgical identification of the SLNs, a peritumoral injection of methylene blue was performed at the time of surgery. This study reports a widely available technique for SLN mapping using digital radiographs in combination with a water-soluble medium, representing a cost-effective alternative to other SLN mapping procedures. Based on our results, this technique can be effective for SLNs mapping in dogs with MCTs but further comparative studies are needed to assess its reliability and efficacy in different tumours.  相似文献   
6.
ABSTRACT Fusarium oxysporum f. sp. canariensis causes Fusarium wilt disease on the Canary Island date palm (Phoenix canariensis). To facilitate disease management, a polymerase chain reaction diagnostic method has been developed to rapidly detect the pathogen. A partial genomic library of F. oxysporum f. sp. canariensis isolate 95-913 was used to identify a DNA sequence diagnostic for a lineage containing all tested isolates of F. oxysporum f. sp. canariensis. Two oligonucleotide primers were designed and used to amplify a 567-bp fragment with F. oxysporum f. sp. canariensis DNAs. DNA from 61 outgroup isolates did not amplify using these primers. Once the primers were shown to amplify a 0.567-kb fragment from DNA of all the F. oxysporum f. sp. canariensis isolates tested, a rapid DNA extraction procedure was developed that led to the correct identification of 98% of the tested F. oxysporum f. sp. canariensis isolates.  相似文献   
7.
A 5-year-old Holsteiner gelding from Germany was presented 2 months after a whitish discoloration of the left cornea was observed. Cytologic examination revealed intra- and extracellular globular structures, up to 4 micro m in size, consisting of a central spherical deeply basophilic body surrounded by an unstained halo. The structures were morphologically consistent with Histoplasma spp. Infection with Histoplasma organisms is not endemic in Europe. Topical use of fluconazole was successful in eliminating Histoplasma organisms within 10 days of initiation of treatment.  相似文献   
8.
9.

Background  

The β-glucuronidase (GUS) gene reporter system is one of the most effective and employed techniques in the study of gene regulation in plant molecular biology. Improving protocols for GUS assays have rendered the original method described by Jefferson amenable to various requirements and conditions, but the serious limitation caused by inhibitors of the enzyme activity in plant tissues has thus far been underestimated.  相似文献   
10.
Intravenous paclitaxel has been underused in dogs due to severe and acute hypersensitivity reactions. Subcutaneous (SC) administration of paclitaxel and its safety are unknown. In this preliminary study, SC administration of paclitaxel was evaluated for hypersensitivity reactions and toxicity in 21 dogs with advanced cancer. Dogs received 1 to 5 paclitaxel doses, ranging from 85 to 170 mg/m2, SC every 14 or 21 days. A total of 40 paclitaxel doses were administered and none of the 21 dogs developed systemic or acute local hypersensitivity reactions. Severe skin lesions at the injection site developed in 2 dogs after the 4th injection at the same location. Grade 4 neutropenia was observed in 50% of the dogs 5 days after the first treatment at 115 mg/m2 (n = 14). Two animals developed Grade 5 diarrhea and died likely due to hemodynamic failure or sepsis. Paclitaxel can be administered SC in dogs with no hypersensitivity reaction.  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