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   194篇
  免费   23篇
林业   9篇
农学   29篇
基础科学   4篇
  34篇
综合类   13篇
农作物   15篇
水产渔业   9篇
畜牧兽医   91篇
园艺   4篇
植物保护   9篇
  2023年   1篇
  2022年   7篇
  2021年   2篇
  2020年   9篇
  2019年   7篇
  2018年   14篇
  2017年   13篇
  2016年   7篇
  2015年   5篇
  2014年   12篇
  2013年   19篇
  2012年   13篇
  2011年   8篇
  2010年   8篇
  2009年   4篇
  2008年   6篇
  2007年   11篇
  2006年   5篇
  2005年   4篇
  2004年   8篇
  2003年   5篇
  2002年   5篇
  2001年   2篇
  2000年   5篇
  1999年   2篇
  1998年   3篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   3篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1979年   3篇
  1978年   4篇
  1977年   1篇
  1974年   2篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
  1964年   1篇
排序方式: 共有217条查询结果,搜索用时 31 毫秒
91.
Sera of several canine patients contained an isoenzyme of alkaline phosphatase (ALP) that resembled intestinal ALP with respect to heat inactivation, L-phenylalanine inhibition, and sensitivity to anti-canine intestinal ALP antibody, but differed with regard to the electrophoretic migration. The electrophoretic mobility of the isoenzyme was slightly cathodal than that of hepatic ALP, and its migration was reduced, similar to that of hepatic isoenzyme after neuraminidase treatment. This isoenzyme, which could be corticosteroid induced, was in the sera of numerous dogs with hepatobiliary disorders and was different from the hepatic isoenzyme that appeared in the sera of dogs with acute hepatitis, based on anti-canine intestinal ALP antibody interaction, heat inactivation, and electrophoretic migration.  相似文献   
92.
Experimental tenectomies were performed in the mid metacarpal region of the superficial digital flexor (SDF) tendon while the deep digital flexor (DDF) tendon was traumatized in 10 donkeys. In group I (n=8) the deep frozen tendons were used for grafting where as in group II (n=2) no grafting was done. Amniotic membrane casing was performed around grafted SDF and traumatized DDF tendons in group I only. Gross and histomorphological observations were recorded on the last day of the experiment, i.e., on the 15th (n=1), 30th (n=2), 60th (n=2), 90th (n=2) and 120th (n=1), post-operative days (POD) in group I and on the 60th (n=1) and 120th (n=1) POD in group II. Gross intraoperative observations suggested the presence of only thin filamentous adhesions in all but three animals at 30 (two animals) and 60 (one animal) days which were present only in the limited area of grafted tendon as compared to tenectomized SDF tendon that showed thick fibrous adhesion and thickening at both the cut ends. However, DDF tendon showed no adhesions in all except one animal of group I as compared to group II where adhesions were noticed in both the animals. Histological examination suggested an increase in fibroblastic activity at 2 weeks after grafting. Extrinsic and intrinsic healing response was observed in grafted tendons. Inflammatory reaction was reabsorbed by one month. The bundle formation was observed from two to three months. The histological structure appeared near normal by 4 months. Observation suggested that homologous tendon grafts remain viable by all histological criteria and healing was at a comparatively more advanced stage than tenectomized tendon. However, the traumatized DDF tendon healed completely by two months. It is concluded that the tendon healing was more rapid in animals where deep frozen grafts had been used.  相似文献   
93.
A. K. Singh  S. S. Saini 《Euphytica》1980,29(1):175-176
Summary Angular leaf spot (Isariopsis griseola Sacc.) is a serious disease of French bean in the hills of India and 40 to 70 per cent of the green pods are damaged and rendered unmarketable. Crosses were made between PLB 257, (Phaseolus coccineus L.), a red flowering pole tope, resistant to angular leaf spot, and Contender (Phaseolus vulgaris L.), a highly susceptible commercial cultivar. Studies of the F1, F2, and F3 progenies indicated that PLB 257, carries a recessive gene imparting resistance to angular leaf spot.  相似文献   
94.
Aroma and cooked kernel elongation (CKE) are the two most important quality traits, which differentiate the highly valued Basmati rice from other rice types. Previous studies on genetic analysis have shown that genes/QTLs for these two traits are linked and present on chromosome number 8. We have evaluated the genetic diversity in 33 rice genotypes representative of the traditional Basmati (TB), cross-bred Basmati derived from indica × Basmati rice crosses and non-Basmati (indica and japonica) rice varieties for chromosome number 8 using 26 SSR markers including a specific marker (SCU-SSR1) for RG28 locus; the results have been compared with whole genome based SSR allelic data. The 26 SSR markers (24 polymorphic and 2 monomorphic) amplified a total of 106 alleles; 21 of these alleles were detected to be unique, present in only one genotype. The number and size of the alleles, and polymorphism information content (PIC) values ranged between 1–8, 87–312 and 0–0.736 bp, respectively. SCU-SSR1 marker amplified a total of three alleles (128, 129 and 130 bp). All the TB varieties except Basmati 217 (129 bp) and 7/13 cross-bred Basmati varieties had the 130 bp allele. Alleles of 129 and 128 bp were present in majority of the indica and japonica varieties, respectively. The average pair-wise Jaccard similarity coefficients for TB, indica and japonica varieties were 0.512, 0.483 and 0.251, respectively. Average similarity coefficient between TB and japonica was higher (0.236) compared to that between TB and indicas (0.150). Genetic relationships as determined by Principal Component Analysis (PCA, NTSYS-pc), PowerMarker tree, and Structure analyses, clearly showed high-level differentiation between TB and indica rice varieties, which formed two distinct clusters. The cross-bred Basmati and japonica rice genotypes were placed between these two clusters. Basmati 217 and Ranbir Basmati were quite divergent from rest of the TB varieties. Some of cross-bred Basmati varieties including Super, CSR30 and kernel were closer to TB. Indica rice varieties, CSR10 (salt tolerant variety) and Pokkali (salt tolerant landrace) formed a separate distinct cluster. The Pritchard structure analysis divided the rice genotypes in four major sub-populations of TB, cross-bred Basmati, indica and japonica (including Ranbir Basmati and Basmati 217) rice varieties. Chromosome 8 data-set showed a positive correlation (Mantel test, r = 0.739) with the allelic data-set for 30 SSR markers well-distributed on 12 rice chromosomes indicating a higher level of similarity between the two. The study demonstrates the distinctness of TB from other rice types (indica and japonica) and also provides several novel markers for differentiation between TB rice supplies from cheaper cross-bred Basmati and long-grain non-Basmati varieties at commercial level.  相似文献   
95.
The 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay of the ether, methanol, and aqueous extracts of the spice Myristica malabarica (rampatri) revealed the methanol extract to possess the best antioxidant activity. Column chromatography of the methanol extract led to the isolation of a new 2-acylresorcinol and four known diarylnonanoids of which the diarylnonanoid, malabaricone C, showed the maximum DPPH scavenging activity. Malabaricone C could prevent both Fe(II)- and 2,2'-azobis(2-amidinopropane)dihydrochloride-induced lipid peroxidation (LPO) of rat liver mitochondria more efficiently than curcumin. The anti-LPO activity of malabaricone C was attributed to its better radical scavenging and Fe(II) chelation capacities. The superior activity of malabaricone C was rationalized by a systematic structure-activity correlation of the results obtained with the structurally related diarylnonanoids and curcumin. Malabaricone C also prevented the gamma-ray-induced damage of pBR322 plasmid DNA in a concentration-dependent manner. The radioprotective activity was found to correlate with its (*)OH radical scavenging property, which matched well with that of d-mannitol.  相似文献   
96.
97.
Genetic Resources and Crop Evolution - Indian mustard [Brassica juncea (L.) Czern.] is a major edible oil crop of India. The Indian Council of Agricultural Research—National Bureau of Plant...  相似文献   
98.
99.
100.
ABSTRACT

Cellulose nanocrystals have emerged as replacements for man-made fibers to fabricate environmentally friendly green products. In this work, cellulose nanocrystals (CNCs) of mixed morphology were synthesized by acid hydrolysis of compost using sulfuric acid. Compost, an agro-based biomass feedstock, procured from water hyacinth (Eichhornia crassipes), cow dung, and saw dust (8:1:1) was utilized for the extraction of cellulose, followed by synthesis of CNCs. Compost was prepared using a rotary drum composter and was utilized for the production of CNCs. A two-step procedure for the extraction of CNCs was studied. Initial chemical treatments, including alkali treatment and bleaching, led to the gradual removal of lignin and hemicellulose, while the subsequent sulphuric acid (40%) hydrolysis step yields CNCs in an aqueous suspension. The synthesized CNCs have been studied by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and particle size analyzer. The morphology and dimension of nanofibrils were studied by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques, which showed mixed morphology of rectangular cone type and spherical dimensions. Fabrication of such mixed morphology was found to be dependent on the selected biomass. The trace of metal elements present in the biomass was investigated by scanning electron microscopy-energy dispersive X-ray (SEM-EDX). We report a cost effective and feasible approach of utilizing inexpensive bioresources for production of value added products like CNCs, which could find potential application in the fields of healthcare, biomedical engineering, packaging, etc.  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