全文获取类型
收费全文 | 128篇 |
免费 | 6篇 |
专业分类
林业 | 5篇 |
农学 | 5篇 |
基础科学 | 1篇 |
30篇 | |
综合类 | 19篇 |
农作物 | 45篇 |
水产渔业 | 8篇 |
畜牧兽医 | 13篇 |
园艺 | 2篇 |
植物保护 | 6篇 |
出版年
2023年 | 4篇 |
2022年 | 14篇 |
2021年 | 19篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 7篇 |
2015年 | 2篇 |
2014年 | 10篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
排序方式: 共有134条查询结果,搜索用时 15 毫秒
91.
Yakov Kuzyakov Evgenia Blagodatskaya Sergey Blagodatsky 《Soil biology & biochemistry》2009,41(2):435-439
Kemmitt et al. (Kemmitt, S.J., Lanyon, C.V., Waite, I.S., Wen, Q., Addiscott, T.M., Bird, N.R.A., O'Donnell, A.G., Brookes, P.C., 2008. Mineralization of native soil organic matter is not regulated by the size, activity or composition of the soil microbial biomass - a new perspective. Soil Biology & Biochemistry 40, 61-73) recently proposed the “Regulatory Gate” hypothesis, which states that decomposition of soil organic matter (SOM) is regulated solely by abiotic factors. Without studying the mechanisms of such regulation, Kemmitt with coauthors challenged the classical Winogradsky theory of soil microbiology and questioned the concept of autochtonous and zymogenous microbial populations. In this letter, we revive the significance of microbial activity for SOM decomposition especially for the short-term (hours to weeks) processes and show that the “Regulatory Gate” is (micro)biologically driven.We explain the results of the three experiments in Kemmitt et al. (2008) from a microbiological point of view and suggest that SOM decomposition is mainly regulated by exoenzymes. We criticize the abiotic Regulatory Gate hypothesis based on bottleneck processes and pools limiting the SOM decomposition rate, comparison of constant and changing environmental conditions, as well as the connection between community structure and functions. We explain the results of Kemmitt et al. (2008) according to the properties of soil microbial community: functional redundancy and inconsistency between the excessive (but largely inactive) pool of total microbial biomass and the real mineralization activity. Finally, we suggest that to gain new perspectives on SOM decomposition and many other biochemical processes, future studies should focus on hot spots of (micro)biological activity (i.e., the rhizosphere, drillosphere, detritosphere, biopores, etc.) rather than on the bulk soil. 相似文献
92.
Belov Grigoriy L. Belosokhov Arseniy F. Kutuzova Irina A. Statsyuk Natalia V. Chudinova Elena M. Alexandrova Alina V. Kokaeva Lyudmila Y. Elansky Sergey N. 《植物病害和植物保护杂志》2018,125(3):311-317
Journal of Plant Diseases and Protection - Colletotrichum coccodes is a plant pathogenic fungus affecting different organs of potato, tomato, and some other plants. The leaf infection with C.... 相似文献
93.
Kibler Natalya A. Nuzhny Vladimir P. Kharin Sergey N. Shmakov Dmitry N. 《Fish physiology and biochemistry》2021,47(4):1329-1339
Fish Physiology and Biochemistry - The spatial–temporal organization of the activation, repolarization and hemodynamics of the heart ventricle in rainbow trout, Oncorhynchus mykiss, adapted... 相似文献
94.
Journal of Soils and Sediments - Nowadays, crude oil contamination of soil is one of the widespread environmental problems. In this paper, we examine the impact of oil contamination on individual... 相似文献
95.
Medvedev S Onishi A Fuchimoto D Iwamoto M Nagai T 《The Journal of reproduction and development》2004,50(1):71-76
The objective was to determine the effect of glucose supplementation on development (to the blastocyst stage) of in vitro matured (IVM) porcine oocytes that were either in vitro fertilized (IVF) or electrically activated (EA). Embryos were incubated for 46 or 58 h post insemination (hpi) in an NCSU37-based medium containing 0.17 mM sodium pyruvate and 2.73 mM sodium lactate (IVC-PyrLac), and then transferred to an NCSU37-based medium containing 5.55 mM glucose (IVC-Glu) and cultured until Days 6 (Day 0 = day of EA or IVF). The proportions of oocytes that had formed full blastocysts by Day 6 following transfer to IVC-glu at 46 hpi was 23.5 and 41.2% in the IVF and EA groups respectively; these were lower (P<0.001) than the proportions of oocytes that formed full blastocysts after transfer at 58 hpi (60.3 and 78.7%). However, there was no significant difference in total cell number (at Day 6) between embryos transferred at 46 vs 58 hpi. We inferred that in vitro-derived pig embryos can efficiently use glucose as an energy source starting at approximately 58 hpi; exposure to glucose at that time enhanced development to the blastocyst stage as well as blastocyst quality. 相似文献
96.
97.
Characterization of Streptomyces spp. Isolated from the Sea Surface Microlayer in the Trondheim Fjord, Norway 下载免费PDF全文
Sigrid Hakvg Espen Fjrvik Kjell D. Josefsen Elena Ian Trond E. Ellingsen Sergey B. Zotchev 《Marine drugs》2008,6(4):620-635
The water surface microlayer is still poorly explored, although it has been shown to contain a high density of metabolically active bacteria, often called bacterioneuston. Actinomycetes from the surface microlayer in the Trondheim fjord, Norway, have been isolated and characterized. A total of 217 isolates from two separate samples morphologically resembling the genus Streptomyces have been further investigated in this study. Antimicrobial assays showed that about 80% of the isolates exhibited antagonistic activity against non-filamentous fungus, Gram-negative, and Gram-positive bacteria. Based on the macroscopic analyses and inhibition patterns from the antimicrobial assays, the sub-grouping of isolates was performed. Partial 16S rDNAs from the candidates from each subgroup were sequenced and phylogenetic analysis performed. 7 isolates with identical 16S rDNA sequences were further studied for the presence of PKS type I genes. Sequencing and phylogenetic analysis of the PKS gene fragments revealed that horizontal gene transfer between closely related species might have taken place. Identification of unique PKS genes in these isolates implies that de-replication can not be performed based solely on the 16S rDNA sequences. The results obtained in this study suggest that streptomycetes from the neuston population may be an interesting source for discovery of new antimicrobial agents. 相似文献
98.
Alexandra S. Silchenko Sergey A. Avilov Pelageya V. Andrijaschenko Roman S. Popov Ekaterina A. Chingizova Pavel S. Dmitrenok Anatoly I. Kalinovsky Anton B. Rasin Vladimir I. Kalinin 《Marine drugs》2022,20(6)
Five new triterpene di-, tri- and tetrasulfated hexaosides (chitonoidosides I (1), J (2), K (3), K1 (4) and L (5)) were isolated from the Far-Eastern sea cucumber Psolus chitonoides, collected near Bering Island (Commander Islands) from a depth of 100–150 m. The structural variability of the glycosides concerned both the aglycones (with 7(8)- or 9(11)-double bonds) and carbohydrate chains differing from each other by the third sugar residue (Xyl or sulfated by C-6 Glc) and/or by the fourth—terminal in the bottom semi-chain—residue (Glc or sulfated by C-6 MeGlc) as well as by the positions of a sulfate group at C-4 or C-6 in the sixth—terminal in the upper semi-chain—residue (MeGlc). Hemolytic activities of these compounds 1–5 against human erythrocytes as well as cytotoxicity against human cancer cell lines, HeLa, DLD-1 and HL-60, were studied. The hexaosides, chitonoidosides K (3) and L (5) with four sulfate groups, were the most active against tumor cells in all the tests. Noticeably, the sulfate group at C-4 of MeGlc6 did not decrease the membranolytic effect of 5 as compared with 3, having the sulfate group at C-6 of MeGlc6. Erythrocytes were, as usual, more sensitive to the action of the studied glycosides than cancer cells, although the sensitivity of leukemia promyeloblast HL-60 cells was higher than that of other tumor cells. The glycosides 1 and 2 demonstrated some weaker action in relation to DLD-1 cells than against other tumor cell lines. Chitonoidoside K1 (4) with a hydroxyl at C 25 of the aglycone was not active in all the tests. The metabolic network formed by the carbohydrate chains of all the glycosides isolated from P. chitonoides as well as the aglycones biosynthetic transformations during their biosynthesis are discussed and illustrated with schemes. 相似文献
99.
Sergey Popov Nikita Paderin Daria Khramova Elizaveta Kvashninova Anatoliy Melekhin Fedor Vityazev 《Marine drugs》2022,20(2)
This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30–42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility. 相似文献
100.
Concentration, ability to motility, motility during the second activation (reactivation), and endogenous respiration were
studied in sperm from two experimental groups of carp males. Group 1 was maintained for 7 days at 15°C (cold water (CW) group),
whereas the second group was subjected to a temperature of 20°C (warm water (WW) group) before sperm sampling. Reactivation
were achieved after incubation of firstly activated sperm in media with osmotic pressure adjusted up to 300 mOsm*kg−1 by increasing K+ concentration. Statistically significant reduction of spermatozoa concentration in CW samples versus WW (from 46.0 ± 12.5
(15°C) to 59.3 ± 7 109 (20°C) spermatozoa /ml) have been observed. The sperm of the CW group required a significantly longer incubation time (37 min)
under isotonic conditions to achieve a maximum percentage of potent motility at repeated activation than the WW group (23 min).
After activation of sperm motility, an increase of respiration rate up to maximum level has been found, this level remained
the same under condition of recovering the potential to repeated activation. During the sperm movement respiration rate, in
CW group (6.1 nmolO2/min/109spermatozoa) and WW (3.9 nmolO2/min/109spermatozoa), was significant higher compared to nonactivated sperm (2.4 nmolO2/min/109spermatozoa for CW and 1.1 nmolO2 /min/109spermatozoa for WW). And keeping males for 7 days at 15°C increase the respiration rate of sperm. 相似文献