全文获取类型
收费全文 | 222篇 |
免费 | 9篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 19篇 |
2011年 | 16篇 |
2010年 | 17篇 |
2009年 | 9篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 7篇 |
2004年 | 10篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1970年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有231条查询结果,搜索用时 218 毫秒
31.
32.
S. Saarnio Jukka Alm Jouko Silvola Annalea Lohila Hannu Nykänen Pertti J. Martikainen 《Oecologia》1997,110(3):414-422
Temporal and spatial variation in CH4 emissions was studied at hummock, Eriophorum lawn, flark and Carex lawn microsites in an oligotrophic pine fen over the growing season using a static chamber method, and CH4 production and oxidation potentials in peat profiles from hummock and flark were determined in laboratory incubation experiments.
Emissions were lowest in the hummocks, and decreased with increasing hummock height, while in the lawns and flarks they increased
with increasing sedge cover. Statistical response functions with water table and peat temperature as independent variables
were calculated in order to reconstruct seasonal CH4 emissions by reference to the time series for peat temperature and water table specific to each microsite type. Mean CH4 emissions in the whole area in the snow-free period of 1993, weighted in terms of the proportions of the microsites, were
1.7 mol CH4 m–2. Potential CH4 production and oxidation rates were very low in the hummocks rising above the groundwater table, but were relatively similar
when expressed per dry weight of peat both in the hummocks and flarks below the water table. The CH4 production potential increased in autumn at both microsites and CH4 oxidation potential seemed to decrease. The decrease in temperature in autumn certainly reduced in situ decomposition processes,
possibly leaving unused substrates in the peat, which would explain the increase in CH4 production potential.
Received: 16 August 1996 / Accepted: 30 November 1996 相似文献
33.
Lahtinen SJ Ouwehand AC Reinikainen JP Korpela JM Sandholm J Salminen SJ 《Applied and environmental microbiology》2006,72(7):5132-5134
Plate counting and four culture-independent flow cytometric assays were used to determine the viability and intrinsic properties of three probiotic strains during storage. The strains showed reduction in plate counts but were able to maintain esterase activity, intact cytoplasmic membrane, and pH gradient. The apparently uncultivable probiotic cells were active and stress resistant. 相似文献
34.
Sanna Saarnio Jukka Alm Pertti J. Martikainen & Jouko Silvola 《Journal of Ecology》1998,86(2):261-268
1 In a glasshouse experiment we studied the effect of raised CO2 concentration (720 p.p.m.) on CH4 emission at natural boreal peat temperatures using intact cores of boreal peat with living vascular plants and Sphagnum mosses. After the end of the growing season half of the cores were kept unnaturally warm (17–20 °C). The potential for CH4 production and oxidation was measured at the end of the emission experiment.
2 The vascular cores ('Sedge') consisted of a moss layer with sedges, and the moss cores (' Sphagnum ') of Sphagnum mosses (some sedge seedlings were removed by cutting). Methane efflux was 6–12 times higher from the Sedge cores than from the Sphagnum cores. The release of CH 4 from Sedge cores increased with increasing temperature of the peat and decreased with decreasing temperature. Methane efflux from Sphagnum cores was quite stable independent of the peat temperatures.
3 In both Sedge and Sphagnum samples, CO2 treatment doubled the potential CH4 production but had no effect on the potential CH4 oxidation. A raised concentration of CO2 increased CH4 efflux weakly and only at the highest peat temperatures (17–20 °C).
4 The results suggest that in cool regions, such as boreal wetlands, temperature would restrict decomposition of the extra substrates probably derived from enhanced primary production of mire vegetation under raised CO2 concentrations, and would thus retard any consequent increase in CH4 emission. 相似文献
2 The vascular cores ('Sedge') consisted of a moss layer with sedges, and the moss cores (' Sphagnum ') of Sphagnum mosses (some sedge seedlings were removed by cutting). Methane efflux was 6–12 times higher from the Sedge cores than from the Sphagnum cores. The release of CH
3 In both Sedge and Sphagnum samples, CO
4 The results suggest that in cool regions, such as boreal wetlands, temperature would restrict decomposition of the extra substrates probably derived from enhanced primary production of mire vegetation under raised CO
35.
Catherine E. Christie John P. Smol Pertti Huttunen Jouko Meriläinen 《Hydrobiologia》1988,161(1):237-243
Chrysophyte (mallomonadacean) scales were examined from the surface sediments of 18 lakes from eastern Finland, representing a wide range of limnological characteristics. Scales were always well preserved and 23 taxa were observed. The relative frequencies of the dominant taxa were plotted relative to the average autumn lakewater pH. The distribution of chrysophyte species in the calibration set was ordinated by means of DECORANA analysis. The occurrence of these species appeared to be closely related to pH, colour and nutrients in the ordinated lake groups. Chrysophyte scales are potentially useful environmental and paleolimnological indicators in eastern Finland. 相似文献
36.
Left ventricular mass, geometry, and filling in endurance athletes: association with exercise blood pressure 总被引:2,自引:0,他引:2
Karjalainen Jouko; Mantysaari Matti; Viitasalo Matti; Kujala Urho 《Journal of applied physiology》1997,82(2):531-537
Karjalainen, Jouko, Matti Mäntysaari, MattiViitasalo, and Urho Kujala. Left ventricular mass, geometry,and filling in endurance athletes: association with exercise bloodpressure. J. Appl. Physiol. 82(2):531-537, 1997.We studied whether left ventricular (LV) mass andconcentricity [relative myocardial volume (RMV)] areassociated with exercise blood pressure (BP) in athletes. LV structureand filling were evaluated by Doppler echocardiography and BP inmaximal bicycle ergometry and isometric handgrip tests on 32 maleendurance athletes and 15 age-matched controls. Indexed LV mass was 145 ± 14 (SD) g/m in athletes and 93 ± 20 g/m incontrols. Mass was not associated with BP at rest or inlow-grade exercise, but with heavier exercise loads this associationstrengthened in athletes, being maximal at peak exercise(r = 0.65 for mass and 0.58 forindexed mass; P < 0.001). Multivariate analysis indicated that BP at peakexercise accounted for 34% and the amount of training for anadditional 11% of the variance in indexed LV mass. RMV was 21% largerin athletes. Only the increase in systolic BP during handgrip explainedsignificantly (19%) the variance in RMV. LV filling velocities werenot associated with mass, RMV, or BP. We conclude that in enduranceathletes LV mass is associated with BP in heavy dynamic exercise and LVconcentricity with BP response in static exercise. 相似文献
37.
Saku V??t?inen Henna Cederberg Risto Roine Sirkka Kein?nen-Kiukaanniemi Jouko Saramies Hannu Uusitalo Jaakko Tuomilehto Janne Martikainen 《PloS one》2016,11(2)
Objectives
Present study examines the relationship between the estimated risk of developing type 2 diabetes (T2D) and health-related quality of life (HRQoL). We quantify the association between Finnish Diabetes Risk Score (FINDRISC) and HRQoL, and examine the potential use of FINDRISC as tool to evaluate HRQoL indirectly.Methods
We conducted a cross-sectional study comprising 707 Finnish people without a diagnosis of T2D between the ages of 51 and 75 years. The risk of developing T2D was assessed using the validated and widely used FINDRISC (range 0–26 points), and quality of life was measured using two preference-based HRQoL instruments (15D and SF-6D) and one health profile instrument (SF-36). Effects of the individual FINDRISC items and demographic and clinical characteristics, such as co-morbidities, on HRQoL were studied using multivariable Tobit regression models.Results
Low HRQoL was significantly and directly associated with the estimated risk of developing T2D. An approximate 4–5 point change in FINDRISC score was observed to be associated with clinically noticeable changes in the preference-based instrument HRQoL index scores. The association between HRQoL and the risk of developing T2D was also observed for most dimensions of HRQoL in all applied HRQoL instruments. Overall, old age, lack of physical activity, obesity, and history of high blood glucose were the FINDRISC factors most prominently associated with lower HRQoL.Conclusions
The findings may help the health care professionals to substantiate the possible improvement in glucose metabolism and HRQoL potentially achieved by lifestyle changes, and better convince people at high risk of T2D to take action towards healthier lifestyle habits. FINDRISC may also provide an accurate proxy for HRQoL, and thus by estimating the risk of T2D with the FINDRISC, information about patients’ HRQoL may also be obtained indirectly, when it is not feasible to use HRQoL instruments. 相似文献38.
Jouko Silvola 《Ecography》1984,7(2):177-181
Carbon dioxide production by the Bombus terrestris queen was measured at different temperatures (10–30°C) and during different activities of the bumblebee. During flight the CO2 production averaged 50 ml g−1 (fresh weight) h−1 and was only slightly affected by temperature. During rest (with a readiness to fly) and incubation the respiration rate clearly increased with decreasing temperature (5–40 and 13–56 ml g−1 h−1 , respectively), whilst during torpor it increased with temperature (0.1–1.7 ml g−1 h−1 at temperatures from 10 to 30°C).
The expenditure of energy as calculated from the continuous respiration measurements agreed well with the amount of energy obtained from food (discrepancy 6–19%). The energy budget of an incubating queen was correctly predicted using the measured respiratory functions, prevailing temperatures, and the behaviour of the queen. The number of flower visits needed to fulfil the daily energy requirements of an incubating queen is discussed. 相似文献
The expenditure of energy as calculated from the continuous respiration measurements agreed well with the amount of energy obtained from food (discrepancy 6–19%). The energy budget of an incubating queen was correctly predicted using the measured respiratory functions, prevailing temperatures, and the behaviour of the queen. The number of flower visits needed to fulfil the daily energy requirements of an incubating queen is discussed. 相似文献
39.
Sanna S. Virtanen Jouko Sandholm Gennady Yegutkin Kalervo H. Väänänen Pirkko L. Härkönen 《Cell biology international》2010,34(8):815-826
The mevalonate synthesis pathway produces intermediates for isoprenylation of small GTPases, which are involved in the regulation of actin cytoskeleton and cell motility. Here, we investigated the role of the prenylation transferases in the regulation of the cytoskeletal organization and motility of PC‐3 prostate cancer cells. This was done by using FTI‐277, GGTI‐298 or NE‐10790, the specific inhibitors of FTase (farnesyltransferase), GGTase (geranylgeranyltransferase)‐I and ‐II, respectively. Treatment of PC‐3 cells with GGTI‐298 and FTI‐277 inhibited migration and invasion in a time‐ and dose‐dependent manner. This was associated with disruption of F‐actin organization and decreased recovery of GFP–actin. Immunoblot analysis of various cytoskeleton‐associated proteins showed that the most striking change in GGTI‐298‐ and FTI‐277‐treated cells was a markedly decreased level of total and phosphorylated cofilin, whereas the level of cofilin mRNA was not decreased. The treatment of PC‐3 cells with GGTI‐298 also affected the dynamics of GFP–paxillin and decreased the levels of total and phosphorylated paxillin. The levels of phosphorylated FAK (focal adhesion kinase) and PAK (p‐21‐associated kinase)‐2 were also lowered by GGTI‐298, but levels of paxillin or FAK mRNAs were not affected. In addition, GGTI‐298 had a minor effect on the activity of MMP‐9. RNAi knockdown of GGTase‐Iβ inhibited invasion, disrupted F‐actin organization and decreased the level of cofilin in PC‐3 cells. NE‐10790 did not have any effect on PC‐3 prostate cancer cell motility or on the organization of the cytoskeleton. In conclusion, our results demonstrate the involvement of GGTase‐I‐ and FTase‐catalysed prenylation reactions in the regulation of cytoskeletal integrity and motility of prostate cancer cells and suggest them as interesting drug targets for development of inhibitors of prostate cancer metastasis. 相似文献
40.
Henriette Santa-Nokki Jani Kallioinen Jouko Korppi-Tommola 《Photochemical & photobiological sciences》2007,6(1):63-66
A new dye-sensitized solar cell driven electrochromic device has been fabricated. The device consists of an electrochromic display and a solar cell in a single nanocrystalline film. The optimization of the electrochromic and the solar cell functions was carried out. An applied potential of 1.0 V was required for coloring and the best solar energy conversion efficiency 1.1% was achieved. The efficiency may be compared to an efficiency of 4.6% obtained in a similar dye-sensitized solar cell without the display property. Coloring and bleaching times of the device were less than one second and a transmittance change from 38.7% (bleached) to 15.9% (colored) at best was achieved. The optimization of the electrochromic property of the device lead to decreasing efficiency of the solar cell and vice versa. 相似文献