全文获取类型
收费全文 | 1502篇 |
免费 | 73篇 |
国内免费 | 1篇 |
专业分类
林业 | 140篇 |
农学 | 220篇 |
基础科学 | 23篇 |
302篇 | |
综合类 | 47篇 |
农作物 | 88篇 |
水产渔业 | 46篇 |
畜牧兽医 | 515篇 |
园艺 | 66篇 |
植物保护 | 129篇 |
出版年
2023年 | 10篇 |
2022年 | 22篇 |
2021年 | 33篇 |
2020年 | 31篇 |
2019年 | 24篇 |
2018年 | 67篇 |
2017年 | 56篇 |
2016年 | 68篇 |
2015年 | 37篇 |
2014年 | 40篇 |
2013年 | 119篇 |
2012年 | 56篇 |
2011年 | 77篇 |
2010年 | 56篇 |
2009年 | 47篇 |
2008年 | 67篇 |
2007年 | 55篇 |
2006年 | 45篇 |
2005年 | 40篇 |
2004年 | 34篇 |
2003年 | 39篇 |
2002年 | 41篇 |
2001年 | 28篇 |
2000年 | 26篇 |
1999年 | 29篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 18篇 |
1991年 | 20篇 |
1990年 | 30篇 |
1989年 | 21篇 |
1988年 | 14篇 |
1987年 | 20篇 |
1986年 | 17篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 21篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1970年 | 8篇 |
1969年 | 14篇 |
1968年 | 12篇 |
排序方式: 共有1576条查询结果,搜索用时 46 毫秒
991.
Hazem Ramadan Sushim K. Gupta Poonam Sharma Marwa Ahmed Lari M. Hiott John B. Barrett Tiffanie A. Woodley Jonathan G. Frye Charlene R. Jackson 《Zoonoses and public health》2020,67(3):324-329
The emergence of NDM‐producing Escherichia coli has considerably threatened human and animal health worldwide. This study describes for the first time in Egypt, the draft genome sequences of emerging NDM‐5‐producing E. coli from humans and dogs, and investigates genetic relatedness between isolates from both sources. Two E. coli from human urine and seven from environmental clinical samples of dogs exhibited resistance to carbapenems and harbouring blaNDM were subjected to Illumina Miseq whole‐genome sequencing (WGS). Assembly and analysis of the reads were performed to identify resistance genes, multilocus sequence types (MLST), plasmid replicon types (Inc) and insertion sequences (IS) of the blaNDM region; core genome MLST (cgMLST) analysis was also performed. Two different NDM alleles were identified; blaNDM‐5 in E. coli HR119 from the urine of a healthy person and environmental samples of dogs, and blaNDM‐1 in E. coli HR135 from a human patient's urine. Multiple mobilizable resistance genes to different antimicrobial classes were identified except the colistin resistance gene, mcr. E. coli isolates from humans and dogs were assigned to different sequence types (STs). Using cgMLST, dog isolates clustered together with only 1–2 allellic differences; however, human E. coli showed 1,978 different allelles compared with dog isolates. Plasmidfinder results indicated the presence of an IncX3 replicon in blaNDM‐5‐producing E. coli; however, blaNDM‐1 was linked to IncCoIKP3. Notably, the NDM region (3 Kb) in all isolates from humans and dogs was highly similar with variable flanking sequences that represented different IS elements. This study reports the first emergence of NDM‐5‐producing E. coli from dogs in Egypt that shared some genetic features with human isolates and could be considered potential public health threats. 相似文献
992.
Sharma Amrita Singla Lachhman Das Tuli Ashuma Kaur Paramjit Bal Mandeep Singh 《Tropical animal health and production》2015,47(1):251-257
Tropical Animal Health and Production - Duplex PCR consisting of two primer sets within a single mixture for the simultaneous detection of Anaplasma marginale and Trypanosoma evansi was... 相似文献
993.
Maize and berseem are among the most important crops in India and several other countries in the world. Irrigation is provided to these crops to get higher production; hence, determining the water requirements of these crops is important for irrigation planning. Improved water management of these crops requires accurate scheduling of irrigation, which in turn requires accurate measurement of crop evapotranspiration (ETc). Thus, the first objective of this study was to measure daily, weekly and seasonal ETc of maize and berseem directly from weighing type lysimeters. Experiments were conducted in a set of two electronic weighing-type lysimeters of 7.82 m3 to measure the hourly ETc of maize and berseem from June 1996 to April 1998 at Karnal, India. The average daily ETc of maize varied from <2.8 mm day-1 in the early growing period to >4 mm day-1 at development and reproductive stages. The peak daily ETc of maize was 7.7 mm day-1 and this occurred 9 weeks after sowing (WAS) at the silking stage of maize when leaf area index (LAI) was 5.5. The measured seasonal ETc of maize was 354 mm. In the case of berseem, the average daily ETc was 0.9 mm day-1 at the initial stage, achieved a peak value of 6.9 mm day-1 between 25 and 26 WAS during the fifth cut. The measured seasonal ETc of berseem was 480 mm. Precise information on the crop coefficient, which is required for regional-scale irrigation planning, is lacking for semi-arid climates such as those found in north India. Therefore, the second objective of this study was to develop crop coefficients (Kc) for maize and berseem from ETc measurements and weather data. The estimated values of Kc for maize by the Penman-Monteith method at the four crop growth stages; namely, initial, crop development, mid-season and maturity, were 0.55, 1.00, 1.23 and 0.64, respectively, and the corresponding values for berseem were 0.76, 0.82, 1.11 and 1.24, respectively. In the case of these two crops, actual Kc values determined from this study are different from those suggested by the FAO (Allen et al. 1998), indicating the need for generating these values at the local/ regional level. 相似文献
994.
995.
Rongala Laxmivandana Chhaya Patole Tilak Raj Sharma Kewal Krishan Sharma Soumen Naskar 《Reproduction in domestic animals》2021,56(6):928-935
The differential proteins associated with plasma membrane of spermatozoa are less known, identification of which shall help overcome limitations of currently used methods of sperm sexing, considered as a high priority for livestock sector of many countries. This study has reported plasma membrane proteomics of unsorted spermatozoa and differential expression of plasma membrane-associated proteins between X- and Y-chromosome bearing spermatozoa of indicus cattle (Bos indicus). Isolation of plasma membrane fraction using percoll gradient, relatively a rapid method, from bovine spermatozoa has been reported to enrich isolation of plasma membrane proteins. Significant enrichment for plasma membrane-associated proteins was observed in plasma membrane fraction (p < .05) as compared to the total cell lysate using LC-MS/MS. Furthermore, these experiments were conducted in flow cytometry sorted, sexed-semen samples. Thirteen proteins were identified as differentially abundant between X- and Y-sorted spermatozoa. Among these, two proteins were downregulated in Y-sorted spermatozoa compared to the X-sorted spermatozoa (p < .05), while four and seven proteins could be noted in X- and Y-sorted spermatozoa, respectively. Proteins that are presumed to support sperm capacitation and sperm migration velocity were found to be abundant in Y-sorted spermatozoa while those associated with structural molecule activity were identified as abundant in X-sorted spermatozoa in the present study. Our study provides better insight into the plasma membrane proteomics of spermatozoa of indicus cattle and furnishes data that might aid in design and development of alternate and open technology for sex-sorting of semen. 相似文献
996.
997.
Variyar PS Ahmad R Bhat R Niyas Z Sharma A 《Journal of agricultural and food chemistry》2003,51(27):7945-7950
Volatile aroma principles, nonvolatile taste constituents (caffeine and chlorogenic and caffeic acids), and glycosidically bound aroma compounds of monsooned and nonmonsooned raw arabica coffee were analyzed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Among the most potent odor active constituents known to contribute to the aroma of the green beans, 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 4-vinylguaiacol, beta-damascenone, (E)-2-nonenal, trans,trans-2,4-decadienal, phenylacetaldehyde, and 3-methylbutyric acid were detected by GC-MS in both samples. A decrease in content of methoxypyrazines and an increase in 4-vinylguaiacol and isoeugenol resulted in a dominant spicy note of monsooned coffee. These phenolic compounds exist partly as their glycosides, and their release from the bound precursors during monsooning accounted for their higher content in monsooned coffee. A considerable decrease in astringent chlorogenic acid as a consequence of hydrolysis to bitter caffeic acid was noted in monsooned coffee. Radiation processing of nonmonsooned beans at a dose of 5 kGy resulted in an increased rate of monsooning. At this dose a quantitative increase in most of the aroma active components could be observed in all samples studied. Hydrolysis of chlorogenic acid to caffeic acid was noted in radiation-processed monsooned coffee beans irrespective of whether the treatment was carried out before or after monsooning. These changes were, however, not observed in irradiated, nonmonsooned coffee beans, suggesting an enzymatic rather than a radiolytic cleavage of chlorogenic acid. A rationale behind the mechanism of monsooning and radiation-induced enhancement of the monsooning process is discussed. 相似文献
998.
An endogenous polysomal cyclic AMP-dependent protein kinase specifically phosphorylates a 150,000-dalton peptide bound to an adrenocortical polyadenylated messenger ribonucleoprotein complex. There is a possibility that this protein is a physiological substrate of cyclic AMP-dependent protein kinase and that the phosphorylation and dephosphorylation of this substrate may be important in the translation control of adrenal polyadenylated messenger RNA. 相似文献
999.
Sharma Samriti Chauhan Arjun Kumar Raj Dobhal Sneha Kaur Rajinder Kumar Krishan Verma Kamlesh 《Genetic Resources and Crop Evolution》2022,69(1):11-38
Genetic Resources and Crop Evolution - Food is indispensable for fulfilling the nutritional requirements of living beings. The principal source of food, nutrition and feed are horticultural... 相似文献
1000.
R. Sur H. P. S. Nagi S. Sharma K. S. Sekhon 《Plant foods for human nutrition (Dordrecht, Netherlands)》1993,44(1):35-44
Sound and sprouted flours (24 and 48 hr) from bread wheat (WL-1562), durum wheat (PBW-34) and triticale (TL-1210) were stored at room temperature (34.8°C) and relative humidity (66.7%) for 0, 45, 90 and 135 days to assess the changes in physico-chemical and baking properties. Protein, gluten, sedimentation value, starch and crude fat decreased during storage in all the samples; however, the decrease was more in sprouted flours. Free amino acids, proteolytic activity, diastatic activity and damaged starch decreased with increase in storage period. Total sugars and free fatty acids increased more rapidly in the flours of sprouted wheats during 135 days of storage. Loaf volume of breads decreased during storage in both sound and sprouted flour but the mean percent decrease in loaf volume was more in stored sound flours. Aging of sprouted flour for 45 days improved the cookie and cake making properties but further storage was of no value for these baked products.Chapati making properties of stored sound and sprouted flour were inferior to that of fresh counterparts. 相似文献