全文获取类型
收费全文 | 343篇 |
免费 | 20篇 |
出版年
2021年 | 5篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 17篇 |
2012年 | 28篇 |
2011年 | 24篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 21篇 |
2007年 | 18篇 |
2006年 | 18篇 |
2005年 | 26篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 22篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 7篇 |
1998年 | 10篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有363条查询结果,搜索用时 15 毫秒
1.
Short-timescale variability of picophytoplankton abundance and cellular parameters in surface waters of the Alboran Sea (western Mediterranean) 总被引:1,自引:0,他引:1
Jacquet Stephan; Prieur Louis; Avois-Jacquet Carol; Lennon Jean-Francois; Vaulot Daniel 《Journal of plankton research》2002,24(7):635-651
The Alboran Sea (western Mediterranean) is characterized bya well-defined hydrological structure, the Almeria (Spain)Oran(Algeria) geostrophic front. During the Almofront-2 cruise (November22, 1997 to January 18, 1998), high frequency sampling ( 相似文献
2.
3.
The past, present and future of childhood malaria mortality in Africa 总被引:11,自引:0,他引:11
During the past few years, there has been a historic series of declarations of renewed commitment to malaria control in Africa. Whether the burden of malaria is increasing in Africa is a moot point. This article attempts to re-construct the evidence for the trends in childhood mortality as a result of Plasmodium falciparum infection over the last century in Africa. 相似文献
4.
5.
Yuling Chi Jean-Francois Jasmin Yoshinori Seki Michael P. Lisanti Maureen J. Charron David J. Lefer Victor L. Schuster 《PloS one》2015,10(6)
Inhibiting the synthesis of endogenous prostaglandins with nonsteroidal anti-inflammatory drugs exacerbates arterial hypertension. We hypothesized that the converse, i.e., raising the level of endogenous prostaglandins, might have anti-hypertensive effects. To accomplish this, we focused on inhibiting the prostaglandin transporter PGT (SLCO2A1), which is the obligatory first step in the inactivation of several common PGs. We first examined the role of PGT in controlling arterial blood pressure blood pressure using anesthetized rats. The high-affinity PGT inhibitor T26A sensitized the ability of exogenous PGE2 to lower blood pressure, confirming both inhibition of PGT by T26A and the vasodepressor action of PGE2 T26A administered alone to anesthetized rats dose-dependently lowered blood pressure, and did so to a greater degree in spontaneously hypertensive rats than in Wistar-Kyoto control rats. In mice, T26A added chronically to the drinking water increased the urinary excretion and plasma concentration of PGE2 over several days, confirming that T26A is orally active in antagonizing PGT. T26A given orally to hypertensive mice normalized blood pressure. T26A increased urinary sodium excretion in mice and, when added to the medium bathing isolated mouse aortas, T26A increased the net release of PGE2 induced by arachidonic acid, inhibited serotonin-induced vasoconstriction, and potentiated vasodilation induced by exogenous PGE2. We conclude that pharmacologically inhibiting PGT-mediated prostaglandin metabolism lowers blood pressure, probably by prostaglandin-induced natriuresis and vasodilation. PGT is a novel therapeutic target for treating hypertension. 相似文献
6.
Tereza Krejcova Miroslava Smelcova Jaroslav Petr Jean-Francois Bodart Marketa Sedmikova Jan Nevoral Marketa Dvorakova Alena Vyskocilova Ivona Weingartova Veronika Kucerova-Chrpova Eva Chmelikova Lenka Tumova Frantisek Jilek 《PloS one》2015,10(1)
Porcine oocytes that have matured in in vitro conditions undergo the process of aging during prolonged cultivation, which is manifested by spontaneous parthenogenetic activation, lysis or fragmentation of aged oocytes. This study focused on the role of hydrogen sulfide (H2S) in the process of porcine oocyte aging. H2S is a gaseous signaling molecule and is produced endogenously by the enzymes cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (MPST). We demonstrated that H2S-producing enzymes are active in porcine oocytes and that a statistically significant decline in endogenous H2S production occurs during the first day of aging. Inhibition of these enzymes accelerates signs of aging in oocytes and significantly increases the ratio of fragmented oocytes. The presence of exogenous H2S from a donor (Na2S.9H2O) significantly suppressed the manifestations of aging, reversed the effects of inhibitors and resulted in the complete suppression of oocyte fragmentation. Cultivation of aging oocytes in the presence of H2S donor positively affected their subsequent embryonic development following parthenogenetic activation. Although no unambiguous effects of exogenous H2S on MPF and MAPK activities were detected and the intracellular mechanism underlying H2S activity remains unclear, our study clearly demonstrates the role of H2S in the regulation of porcine oocyte aging. 相似文献
7.
8.
Stephane Renaud Philippe Jean-Francois Jean-Claude Anne-Marie Olivier 《Journal of electromyography and kinesiology》2009,19(5):922-930
ObjectiveThe objective of this work was to study modifications in motor control through surface electromyographic (sEMG) activity during a very short all-out cycling exercise.MethodsTwelve male cyclists (age 23 ± 4 years) participated in this study. After a warm-up period, each subject performed three all-out cycling exercises of 6 s separated by 2 min of complete rest. This protocol was repeated three times with a minimum of 2 days between each session. The braking torque imposed on cycling motion was 19 N m. The sEMG of the vastus lateralis was recorded during the first seven contractions of the sprint. Time–frequency analysis of sEMG was performed using continuous wavelet transform. The mean power frequency (MPF, qualitative modifications in the recruitment of motor units) and signal energy (a quantitative indicator of modifications in the motor units recruitment) were computed for the frequency range 10–500 Hz.ResultssEMG energy increased (P ? 0.05) between contraction number 1 and 2, decreased (P ? 0.05) between contraction number 2 and 3 then stabilized between contraction number 3 and 7 during the all-out test. MPF increased (P ? 0.05) during the all-out test. This increase was more marked during the first two contractions.ConclusionsThe decrease in energy and the increase in the sEMG MPF suggest a large spatial recruitment of motor units (MUs) at the beginning of the sprint followed by a preferential recruitment of faster MUs at the end of the sprint, respectively. 相似文献
9.
Translocation of DNA and protein fibers through narrow constrictions is a ubiquitous and crucial activity of bacterial cells. Bacteria use specialized machines to support macromolecular movement. A very important step toward a mechanistic understanding of these translocation machines is the characterization of their physical properties at the single molecule level. Recently, four bacterial transport processes have been characterized by nanomanipulation at the single molecule level, DNA translocation by FtsK and SpoIIIE, DNA import during transformation, and the related process of a type IV pilus retraction. With all four processes, the translocation rates, processivity, and stalling forces were remarkably high as compared with single molecule experiments with other molecular motors. Although substrates of all four processes proceed along a preferential direction of translocation, directionality has been shown to be controlled by distinct mechanisms. 相似文献
10.
Daniel Delille Emilien Pelletier Arturo Rodriguez-Blanco Jean-Francois Ghiglione 《Polar Biology》2009,32(10):1521-1528
In an attempt to evaluate the potential of petroleum bioremediation at high latitudes environments, microcosm studies using
Antarctic coastal seawater contaminated with diesel or crude oil were conducted in Kerguelen Archipelago (49°22′S, 70°12′E).
Microcosms were incubated at three different temperatures (4, 10 and 20°C). During experiments, changes observed in microbial
assemblages (total direct count, heterotrophic cultivable microorganisms and hydrocarbon-degrading microorganisms) were generally
similar for all incubation temperatures, but chemical data showed only some slight changes in biodegradation indices [Σ(C12–C20)/Σ(C21–C32)
and C17/pristane]. The complete data set provided strong evidence of the presence of indigenous hydrocarbon-degrading bacteria
in Antarctic seawater and their high potential for hydrocarbon bioremediation. The rate of oil degradation could be increased
by the addition of a commercial fertilizer, but water temperature had little effects on biodegradation efficiency which is
in conflict with the typical temperature-related assumption predicting 50% rate reduction when temperature is reduced by 10°C.
Global warming of Antarctic seawater should not increase significantly the rate of oil biodegradation in these remote regions. 相似文献