全文获取类型
收费全文 | 193篇 |
免费 | 20篇 |
国内免费 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 14篇 |
2012年 | 13篇 |
2011年 | 10篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 13篇 |
2006年 | 9篇 |
2005年 | 15篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有230条查询结果,搜索用时 187 毫秒
221.
Several fundamental questions remain enigmatic concerning human olfactory
sensitivity, including (i) whether detection threshold differences exist
between the two sides of the nose (and, if so, whether such differences are
influenced by handedness) and (ii) whether bilateral (i.e. binasal)
stimulation leads to lower thresholds than unilateral stimulation (and, if
so, whether the degree of facilitation is inversely related to general
olfactory ability). In this study, and well-validated single staircase
procedure was used to establish bilateral and unilateral detection
thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130
right- and 33 left-handed subjects. No differences in sensitivity between
the left and right sides of the nose were observed in either group.
Bilateral thresholds were lower, on average, than unilateral thresholds
when the latter were categorized in terms of left and right nares. However,
the bilateral thresholds did not differ significantly from those of the
side of the nose with the lower threshold. Overall smell ability, as
measured by the University of Pennsylvania Smell Identification Test, did
not interact with any of the test measures. These data imply that (i) the
left and right sides of the nose do not systematically differ in detection
threshold sensitivity for either dextrals or sinistrals and (ii) if central
integration of left:right olfactory threshold sensitivity occurs, its
effects do not exceed the function of the better side of the nose.
相似文献
222.
Ophioglossum yongrenense Ching ex Z. R. He et W. M. Chu, sp. nov.Species nova aspectu inter O. kawamuram Tagawa et O. parvum Nishida et Kurita Japonicae, differt a priore frondibus pro parte laminis sterilibus praeditis (in illa frondibus omnino laminis sterilibus non praeditis), a posteriore frondibus pro parte laminis sterilibus non praeditis (in O. parvo Nishida et Kurita frondibus omino laminis sterilibus praeditis).…… 相似文献
223.
M. A. K. Lodhi 《American journal of botany》1977,64(3):260-264
Soil properties were found to vary with increasing distance from tree trunks of individuals of the same species, and different species were found to vary in their effects on soil properties. The differences in pH and mineral concentration at different distances from the trunk were often statistically significant even under the same tree. When all species are considered, iron had the least variability at different distances from the trunks of all minerals investigated, followed by potassium. Nitrate nitrogen had the greatest overall variability at different distances from the trunks. Ammonium nitrogen in the soil was always considerably higher than nitrate nitrogen when compared at each distance from the trunk under each species. Low amounts of nitrate nitrogen could not have been due to its uptake by the intact vegetation, because the soil samples were taken before the active growth period. It seems possible that the variable tree litter under different species plays an important role in controlling the soil pH, nitrification, and mineralization. Thus, it appears that in a climax community different dominating species, by developing variable physio-ecological niches, can determine the variable undergrowth vegetation under them. 相似文献
224.
The present study was conducted primarily to determine the occurrence of polypharmacy in patients with schizophrenia on risperidone. The secondary aim was to ascertain the incidence of inappropriate prescribing with anticholinergics. A retrospective review of the medical records of all patients who were being followed up at the out-patient clinic of a tertiary-care hospital in Malaysia was conducted. Only patients who were being prescribed risperidone between 1 June 2008 and 31 December 2008 were included in the study. Demographic data such as patient’s age, gender and race were obtained from the patient’s medical records. In total, 113 patients met the selection criteria. Polypharmacy was found to occur in 34 patients (30.09%), with the majority (76.47%) being on two antipsychotics. In total, 27 patients (34.18%) on monotherapy with risperidone were prescribed an anticholinergic on scheduled dosing, while 19 patients (24.05%) were prescribed it on an as-needed basis. Of the patients on polypharmacy, 26 (76.47%) were on scheduled dosing of anticholinergics, while three (8.82%) were taking the medication on an as-needed basis. Polypharmacy should be avoided, and the use of anticholinergics should be closely reviewed. By adopting more efficient prescribing practices, costs can be reduced and financial resources can instead be channelled towards more beneficial areas for the patients. 相似文献
225.
226.
A. H. Lodhi R. J. M. Bongaerts R. Verpoorte S. A. Coomber B. V. Charlwood 《Plant cell reports》1996,16(1-2):54-57
Summary The gene coding for isochorismate synthase (EC 5.4.99.6) was amplified by the polymerase chain reaction fromEscherichia coli, cloned into a binary vector. and mobilised intoAgrobacterium rhizogenes LBA9402 which was used to transformRubia peregrina. Transgenic roots containing bacterial isochorismate synthase cDNA expressed twice as much isochorismate synthase activity (4.88 pkat/mg protein) as the control roots (2.45 pkat/mg protein) after 10 days in culture, and accumulatedca. 20% higher levels of total anthraquinones after 30 days in culture. Whilst the amount of total alizarin (free and bound) in the transgenic roots was 30% higher than in control roots, the level of free alizarin wasca. 85% higher. 相似文献
227.
M. A. K. Lodhi 《American journal of botany》1975,62(6):618-622
Plant growth inhibitors, which are known to exert synergistic effects on herbaceous vegetation, were isolated and quantified from the soils under hackberry trees. Ferulic, caffeic, and p-coumaric acids were isolated from the soils under hackberry trees collected in January, April, and September from 0–15 and 15–30 cm soil depths. Seed germination bioassay indicated considerably higher phytotoxicity levels of individual plant growth inhibitors in January and April soils, and this toxicity level was more drastic when inhibitors were applied accumulatively. Individual phytotoxins extracted from soil in September were not very inhibitory to seed germination of selected test species; however, accumulative effects were still allelopathic to seed germination. Toxicity levels of individual compounds may reduce or disappear in a given time, but the combined action of these chemicals would still be toxic in croplands or in natural communities. Ecological implications of allelopathy in terms of soil-plant interaction are discussed. 相似文献
228.
229.
230.
Seed germination and salinity tolerance in plant species growing on saline wastelands 总被引:1,自引:0,他引:1
Seven plant species including three chenopods:Suaeda fruticosa, Kochia indica, Atriplex crassifolia and four grasses:Sporobolus arabicus, Cynodon dactylon, Polypogon monspeliensis, Desmostachya bipinnata, varied greatly in their seed germination and growth responses to soil moisture or salinity. The germination percentage of
each species was significantly lower at soil moisture level of 25 % of water holding capacity than at the levels ranging from
50 to 125 %. Increase in salinity resulted in gradual decrease in seed germination of each species. Growth responses of species
to salinity varied widely from significant decrease with slight salinity to stimulation up to salinity levels of 20 dS m-2. Higher K+Na+ratios in plant shoots of all species compared to that in the root medium indicated selective K+uptake. Higher tolerance in chenopod species seems to be attendant on their ability for internal ion regulation.
We are thankful to Mr. Noor Ahmad for his assistance in experimental work. 相似文献