全文获取类型
收费全文 | 1055篇 |
免费 | 104篇 |
国内免费 | 145篇 |
出版年
2024年 | 4篇 |
2023年 | 20篇 |
2022年 | 22篇 |
2021年 | 34篇 |
2020年 | 49篇 |
2019年 | 53篇 |
2018年 | 58篇 |
2017年 | 59篇 |
2016年 | 38篇 |
2015年 | 46篇 |
2014年 | 59篇 |
2013年 | 104篇 |
2012年 | 42篇 |
2011年 | 56篇 |
2010年 | 52篇 |
2009年 | 75篇 |
2008年 | 56篇 |
2007年 | 71篇 |
2006年 | 44篇 |
2005年 | 32篇 |
2004年 | 39篇 |
2003年 | 28篇 |
2002年 | 28篇 |
2001年 | 20篇 |
2000年 | 17篇 |
1999年 | 11篇 |
1998年 | 14篇 |
1997年 | 16篇 |
1996年 | 13篇 |
1995年 | 19篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 12篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有1304条查询结果,搜索用时 140 毫秒
1.
Isam A. Eltoum Saud M. Suliaman Babiker M. Ismail Magdi M. Ali Mamoun M. A. Homeida 《Biotechnic & histochemistry》1993,68(3):146-149
Three stains, Hansel's stain, alkaline erythrocin B (AEB) and naphthalene black (NB), were used to demonstrate eosinophils in the urine of patients infected with Schistosoma haematobium. Hansel's stain was superior to the other two stains; it stained eosinophils bright red and their nuclei faint blue, and they were easily differentiated from neutrophils, lymphocytes, macrophages and epithelial cells. The method using AEB took longer than Hansel's stain and 10% of the specimens were lost during staining with this method. Like eosinophils, the neutrophils took up NB stain and their nuclei stained poorly with the counterstain. 相似文献
2.
3.
4.
Eastern black nightshade (Solanum ptycanthum; EBN) is a problematic weed partly due to its tolerance or resistance to certain herbicides. We examined the effects of an invert emulsion (IE) on the host range and weed control efficacy of the fungus Colletotrichum coccodes (NRRL strain 15547) for biocontrol of EBN. Greenhouse tests demonstrated that several other solanaceous weeds were also infected and killed, and field tests revealed >90% EBN control and dry weight reduction in plants treated with the fungus-IE formulation. These results demonstrate that this IE formulation can promote the efficacy of this bioherbicidal pathogen. 相似文献
5.
Samane Mohammadi Hossein Aroiee Ali Tehranifar Vahid Jahanbakhsh 《Archives Of Phytopathology And Plant Protection》2013,46(13):1603-1610
The development of natural crop protection products as alternatives to the use of synthetic fungicides is currently popular. The aim of this study is to evaluate the antifungal effects of several essential oils against the fungal pathogens, Botrytis cinerea and Rhizopus stolonifer, under in vitro condition. Four essential oils (fennel, black caraway, peppermint and thyme) were each tested at five concentrations (0, 200, 400, 600 or 800 μl l?1). In vitro results showed that the essential oil of black caraway and fennel had the highest fungicidal effect against B. cinerea and R. stolonifer, respectively. The growth of B. cinerea was completely inhibited by the essential oil of black caraway at 400 μl l?1. Fennel oil perfectly inhibited growth of R. stolonifer fungus colonies at concentration higher than 600 μl L?1 in potato dextrose agar medium. Percentage of spores germination was the lowest in medium of Fennel and black caraway essential oils, and was the highest in Thyme ones. These results show that plant essential oils can have a strong effect on reducing post-harvest decay. These plant essential oils could provide an alternative to synthetic chemicals to control post-harvest phytopathogenic fungi on fruit. 相似文献
6.
Reactive oxygen species (ROS) have been widely known to inflict biological damage upon a variety of biological sites. The ability to counteract any such activity has been the subject of this work, in an attempt to comprehend prooxidant metal ion induced oxidation and its possible physiological consequences. Five Mediterranean aqueous herb infusions have been employed in the investigation of possible pro/antioxidant activity promoted by prooxidant iron ions. In the presence of phospholipid liposomes or linoleic acid micelles or 2-deoxy-d-ribose, it was shown that all of the aqueous infusions used exhibited antioxidant activity in comparison to the iron control. The antioxidant activity, studied on 2-deoxy-d-ribose, at three concentration levels in each herb, appears to be dose dependent, albeit non-linear. The total polyphenol content of the investigated herb infusions, however, does not directly correlate with the observed antioxidant activity. The variable, yet effective, antioxidant capacity of the aqueous infusions indicates that their antioxidant components can quench ROS generating activity, brought on different substrates and likely arisen by variable mechanisms involving different ROS. 相似文献
7.
Abstract Close monitoring of the lepidopteran leafroller Cnephasia jactatana under laboratory colonisation revealed few distinct effects of successive rearing on artificial diet on the life cycle. The second laboratory generation had a prolonged development time and altered sex synchronism in pupation and eclosion patterns. Some deleterious changes were observed in later generations, including decreases in fertility, egg hatch and sperm motility, failure of mating adults to separate, and pupal and adult malformations. These changes were not adaptive, but were due to incompatibility with the general purpose diet (GPD) used; they were absent under sub-colonisation on a sheepnut-bean based diet (SBD). Success in the laboratory colonisation of C. jactatana is attributed to a random mating protocol, choice of environmental conditions representing the wild habitat, and a rapid rate of population growth. 相似文献
8.
The parasitic ciliate causing shrimp black gill (sBG) infections in penaeid shrimp has been identified. The sBG ciliate has a unique life cycle that includes an encysted divisional stage on the host’s gills. The ciliature of the encysted trophont stage has been determined and is quite similar to that of the closely related apostomes Hyalophysa bradburyae and H. chattoni. Hyalophysa bradburyae is a commensal ciliate associated with freshwater caridean shrimp and crayfish, while H. chattoni is a common commensal found on North American marine decapods. Based on 18S rRNA gene sequence comparisons, the sBG ciliate is more closely related to the marine species H. chattoni than to the freshwater species H. bradburyae. The unique life cycle, morphology, 18S rRNA gene sequence, hosts, location, and pathology of the sBG ciliate distinguish this organism as a new species, Hyalophysa lynni n. sp. 相似文献
9.
Feng H. Huang Jameel M. Al-Khayri Edward E. Gbur 《In vitro cellular & developmental biology. Plant》1994,30(1):70-74
Summary A micropropagation system was developed forAcacia mearnsii De Wild., which is the principal source of the world’s tanbark and an excellent firewood. Shoot tips 5-mm long from 3-wk-old
seedlings germinated in vitro served as explants. The seeds were germinated on hormone-free MS medium and the shoot tips were
cultured on three-fourth-strength MS medium supplemented with combinations of auxins [indole-3-butyric acid (IBA) andα-naphthaleneacetic acid (NAA)] and cytokinins [kinetin and benzylaminopurine (BAP)]. Cultures were maintained at 25° ± 5°
C and exposed to 12-h photoperiods of cool-white fluorescent light (70 μEm−2·s−1). Multiple shoot formation was promoted by BAP at 2 mg · liter−1 (8.87μM) and higher combined with or without 0.01 mg · liter−1 (0.049μM) IBA. Cytokinins at concentrations of less than 1 mg · liter−1 combined with 0.01 to 0.1 mg · liter−1 auxin inhibited multiple shoot formation and promoted rooting of the shoot tip explants. Shoot multiplication cultures were
maintained by transferring segments of multiple-shoot clusters onto a medium containing 2 mg · liter−1 BAP and 0.01 mg · liter−1 IBA. Although higher levels of BAP promoted more multiple shoot formation, this BAP level allowed shoot elongation as well
as multiplication. In-vitro-produced shoots were induced to root on a range of NAA concentrations (0.0 to 0.8 mg · liter−1[4.3μM]) supplemented to half- or full-strength MS medium. The highest frequency of root proliferation was on half-strength MS medium
supplemented with 0.6 mg · liter−1 (3.22μM) NAA. Plantlets survived in potting soil and exhibited normal growth under greenhouse conditions. 相似文献
10.
《Bioscience, biotechnology, and biochemistry》2013,77(8):1606-1612
We manufactured a new fermented tea by tea-rolling processing of third-crop green tea (Camellia sinensis) leaves and loquat (Eriobotrya japonica) leaves. The mixed fermented tea extract inhibited pancreatic lipase activity in vitro, and effectively suppressed postprandial hypertriacylglycerolemia in rats. Rats fed a diet containing 1% freeze-dried fermented tea extract for 4 weeks had a significantly lower liver triacylglycerol concentration and white adipose tissue weight than those fed the control diet lacking fermented tea extract. The activity of fatty acid synthase in hepatic cytosol markedly decreased in the fermented tea extract group as compared to the control group. The serum and liver triacylglycerol- and body fat-lowering effects of the mixed fermented tea extract were strong relative to the level of dietary supplementation. These results suggest that the new fermented tea product exhibited hypotriacylglycerolemic and antiobesity properties through suppression of both liver fatty acid synthesis and postprandial hypertriacylglycerolemia by inhibition of pancreatic lipase. 相似文献