全文获取类型
收费全文 | 73篇 |
免费 | 6篇 |
专业分类
79篇 |
出版年
2020年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有79条查询结果,搜索用时 15 毫秒
1.
Hatchery selection promotes boldness in newly hatched brown trout (Salmo trutta): implications for dominance 总被引:2,自引:0,他引:2
Sundstrom L. Fredrik; Petersson Erik; Hojesjo Johan; Johnsson Jorgen I.; Jarvi Torbjorn 《Behavioral ecology》2004,15(2):192-198
By using newly hatched (approximately 2 weeks old) brown trout(Salmo trutta) from six families of wild and six families ofsea-ranched origin (seventh generation), we tested the hypothesesthat (1) the hatchery environment selects for increased boldness,and (2) boldness predicts dominance status. Sea-ranched troutspend their first 2 years in the hatchery before being releasedinto the wild at the onset of seaward migration. Trout werepresented with a novel object (tack) and with food (brine shrimp),and their responses were measured and scored in terms of boldness.Siblings with increasing difference in boldness were then pairedin dyadic contests. Fish of sea-ranged origin were on averagebolder than were fish of wild origin, and bolder individualswere more likely to become dominant regardless of origin. Boldnesswas not related to RNA levels, indicating that bold behaviorwas not a consequence of higher metabolism or growth rate. Neitherwas size a predictor of bold behavior or the outcome of dyadiccontests. These results are consistent with studies on olderlife stages showing increased boldness toward predators in hatchery-selectedfish, which suggests that behavioral consequences of hatcheryselection are manifested very early in life. The concordancebetween boldness and dominance may suggest that these behaviorsare linked in a risk prone-aggressive phenotype, which may bepromoted by hatchery selection. However, we also found significantvariation in behavioral and growth-related traits among families,suggesting that heritable variation has not been exhausted bysea-ranching procedures. 相似文献
2.
A growth study of Acropora formosa (Dana) was conducted in situ at a fringing reef in front of Phuket Marine Biological Center, the Andaman Sea, southern Thailand. Monthly extensions of branches tagged with wire were measured in addition to sunshine, rainfall, settlement of sediment, turbidity, salinity, and temperature. The average extension of coral branches was 8 cm in 344 days. Growth was found to be approximately two times faster during the dry northeast monsoon compared with the wet southwest monsoon. Factors which can cause the observed pattern of growth are discussed.Miscellaneous Contributions from PMBC, Thailand, No. 17 相似文献
3.
Max Kaufmann Jorgen Marqverson Kenneth E. Stanley Christian Mouritzen Hans Hvid-Hansen 《Cancer immunology, immunotherapy : CII》1986,22(1):56-61
Summary The distribution of Corynebacterium parvum labeled with 131iodine or 99mtechnetium was studied in 17 patients with bronchogenic carcinoma. The labeled bacteria were given intravenously or intrapleurally and monitored by whole-body gamma tracking and samples of blood and urine. Even though the rate of physical decay is quite different for 131iodine and 99mtechnetium, the tracking time of labeled bacteria was limited to 24 h after injection for both radioactive isotopes. Technetium labeling was preferred because of greater imaging resolution and less radiation dose to the patient. Following intravenous administration, labeled C. parvum was found predominantly in the liver and spleen, and in a lesser amount in the lung. Radioactivity was confined to the pleural cavity after intrapleural injection. These results suggest the combined intravenous and intrapleural route of adjuvant immunosupportive agents such as C. parvum for operable lung cancer patients. 相似文献
4.
Christopher MacDonald Jorgen F P Wojtaszewski Bente Klarlund Pedersen Bente Kiens Erik A Richter 《Journal of applied physiology》2003,95(6):2273-2277
We tested the hypothesis that IL-6 release from muscle during exercise may be related to muscle activity of 5'-AMP-activated protein kinase (AMPK). Eight healthy, well-trained young men completed two 60-min trials on a bicycle ergometer at 70% of their peak oxygen uptake in either a glycogen-depleted or a glycogen-loaded state. IL-6 was released from the leg already after 10 min of exercise in the glycogen-depleted state, whereas no significant release was observed at any time in the loaded state. Nevertheless, plasma IL-6 increased similarly in the two trials from approximately 0.8 pg/ml at rest to approximately 4.5 pg/ml after 60 min of exercise. Activity of alpha1-AMPK (160%) and alpha2-AMPK (145%) was increased at rest in the glycogen-depleted compared with the loaded situation. During exercise, alpha1-AMPK activity did not change from resting levels in both trials, whereas alpha2-AMPK activity increased only in the glycogen-depleted state. After 60 min of exercise in the glycogen-depleted state, individual values of alpha2-AMPK activity correlated significantly (r = 0.87, P < 0.006) with individual values of IL-6 release as well as with average IL-6 release over the entire 60 min (r = 0.86, P < 0.006). The present data are compatible with a role for AMPK in IL-6 release during exercise or a role for IL-6 in activating AMPK. Alternatively, both AMPK and IL-6 are independent sensors of a low muscle glycogen concentration during exercise. In addition, leg release of IL-6 cannot alone explain the increase in plasma IL-6 during exercise. 相似文献
5.
Feeding activity in the Red squirrel (Sciurus vulgaris) 总被引:1,自引:0,他引:1
6.
How to measure,report and verify soil carbon change to realize the potential of soil carbon sequestration for atmospheric greenhouse gas removal 总被引:1,自引:0,他引:1
Pete Smith Jean‐Francois Soussana Denis Angers Louis Schipper Claire Chenu Daniel P. Rasse Niels H. Batjes Fenny van Egmond Stephen McNeill Matthias Kuhnert Cristina Arias‐Navarro Jorgen E. Olesen Ngonidzashe Chirinda Dario Fornara Eva Wollenberg Jorge lvaro‐Fuentes Alberto Sanz‐Cobena Katja Klumpp 《Global Change Biology》2020,26(1):219-241
There is growing international interest in better managing soils to increase soil organic carbon (SOC) content to contribute to climate change mitigation, to enhance resilience to climate change and to underpin food security, through initiatives such as international ‘4p1000’ initiative and the FAO's Global assessment of SOC sequestration potential (GSOCseq) programme. Since SOC content of soils cannot be easily measured, a key barrier to implementing programmes to increase SOC at large scale, is the need for credible and reliable measurement/monitoring, reporting and verification (MRV) platforms, both for national reporting and for emissions trading. Without such platforms, investments could be considered risky. In this paper, we review methods and challenges of measuring SOC change directly in soils, before examining some recent novel developments that show promise for quantifying SOC. We describe how repeat soil surveys are used to estimate changes in SOC over time, and how long‐term experiments and space‐for‐time substitution sites can serve as sources of knowledge and can be used to test models, and as potential benchmark sites in global frameworks to estimate SOC change. We briefly consider models that can be used to simulate and project change in SOC and examine the MRV platforms for SOC change already in use in various countries/regions. In the final section, we bring together the various components described in this review, to describe a new vision for a global framework for MRV of SOC change, to support national and international initiatives seeking to effect change in the way we manage our soils. 相似文献
7.
Electrofusion of syngeneic dendritic cells and tumor generates potent therapeutic vaccine 总被引:4,自引:0,他引:4
Antigen presentation by dendritic cells (DCs) has the potential to elicit therapeutic immune responses against malignant tumors. One strategy utilizing DC-tumor fusion hybrids as cancer vaccine is particularly attractive because of polyclonal presentation of a diverse array of unaltered tumor antigens. We have recently developed a large-scale electrofusion technique for generating DC-tumor heterokaryons and demonstrated their superb immunogenicity. Here, employing the weakly immunogenic MCA205 sarcoma, a single vaccination with electrofusion hybrids eradicated tumors established in the lung, skin, and brain. Immunotherapy required intra-lymphoid vaccine delivery and co-administration of adjuvants such as OX-40R antibody. Tumor eradication was immunologically specific and involved the participation of both CD4 and CD8 T cells. Consistent with DC's functionality of MHC-restriction, the use of syngeneic DCs for fusion was an obligatory requirement. Fusion with allogeneic DCs completely lacked therapeutic effects. These findings provide a strong impetus for treating cancer patients with similarly generated DC-tumor hybrids. 相似文献
8.
Damgaard M Gabrielsen A Heer M Warberg J Bie P Christensen NJ Norsk P 《American journal of physiology. Regulatory, integrative and comparative physiology》2002,283(6):R1404-R1411
The hypothesis was tested that cardiac output (CO) and stroke volume (SV) are increased by a moderate physiological elevation in sodium intake with a more pronounced effect in the ambulatory upright seated than supine position. Fourteen healthy males were investigated during ambulatory and controlled laboratory conditions at the end of two consecutive 5-day periods with sodium intakes of 70 (low) and 250 (high) mmol/24 h or vice versa, respectively. Comparing high and low sodium intake, plasma volume and plasma protein concentrations were 9 and 8% higher in the seated and the supine position, respectively. When seated during laboratory conditions, CO was 5.3 +/- 0.2 l/min on the high sodium intake vs. 4.8 +/- 0.2 l/min on the low (P < 0.05), and SV was 81 +/- 3 vs. 68 +/- 3 ml (P < 0.05). In the supine position, SV was 107 +/- 3 ml on the high vs. 99 +/- 3 ml (P < 0.05) on the low sodium intake, while CO remained unchanged. The difference in CO and SV induced by the change in sodium intake was significantly higher in the seated than in the supine position (P < 0.05). During upright ambulatory conditions, CO was 5.9 +/- 0.2 l/min during the high and 5.2 +/- 0.2 l/min during the low sodium intake (P < 0.05), and SV was 84 +/- 3 and 69 +/- 3 ml (P < 0.05), respectively. Mean arterial pressure was unchanged by the variations in sodium intake. In conclusion, increments in sodium intake within the normal physiological range increase CO and SV and more so in the seated vs. the supine position. These changes are readily detectable during upright, ambulatory conditions. The results indicate that the higher SV and CO could constitute an arterial baroreflex stimulus for the augmented renal sodium excretion. 相似文献
9.
Wojtaszewski JF MacDonald C Nielsen JN Hellsten Y Hardie DG Kemp BE Kiens B Richter EA 《American journal of physiology. Endocrinology and metabolism》2003,284(4):E813-E822
The metabolic role of 5'AMP-activated protein kinase (AMPK) in regulation of skeletal muscle metabolism in humans is unresolved. We measured isoform-specific AMPK activity and beta-acetyl-CoA carboxylase (ACCbeta) Ser(221) phosphorylation and substrate balance in skeletal muscle of eight athletes at rest, during cycling exercise for 1 h at 70% peak oxygen consumption, and 1 h into recovery. The experiment was performed twice, once in a glycogen-loaded (glycogen concentration approximately 900 mmol/kg dry wt) and once in a glycogen-depleted (glycogen concentration approximately 160 mmol/kg dry wt) state. At rest, plasma long-chain fatty acids (FA) were twofold higher in the glycogen-depleted than in the loaded state, and muscle alpha1 AMPK (160%) and alpha2 AMPK (145%) activities and ACCbeta Ser(221) phosphorylation (137%) were also significantly higher in the glycogen-depleted state. During exercise, alpha2 AMPK activity, ACCbeta Ser(221) phosphorylation, plasma catecholamines, and leg glucose and net FA uptake were significantly higher in the glycogen-depleted than in the glycogen-loaded state without apparent differences in muscle high-energy phosphates. Thus exercise in the glycogen-depleted state elicits an enhanced uptake of circulating fuels that might be associated with elevated muscle AMPK activation. It is concluded that muscle AMPK activity and ACCbeta Ser(221) phosphorylation at rest and during exercise are sensitive to the fuel status of the muscle. During exercise, this dependence may in part be mediated by humoral factors. 相似文献
10.
Hawkey CJ Talley NJ Scheiman JM Jones RH Långström G Naesdal J Yeomans ND;NASA/SPACE author group 《Arthritis research & therapy》2007,9(1):R17
Non-steroidal anti-inflammatory drugs (NSAIDs), including selective cyclo-oxygenase-2 (COX-2) inhibitors, cause upper gastrointestinal
(GI) symptoms that are relieved by treatment with esomeprazole. We assessed esomeprazole for maintaining long-term relief
of such symptoms. Six hundred and ten patients with a chronic condition requiring anti-inflammatory therapy who achieved relief
of NSAID-associated symptoms of pain, discomfort, or burning in the upper abdomen during two previous studies were enrolled
and randomly assigned into two identical, multicentre, parallel-group, placebo-controlled studies of esomeprazole 20 mg or
40 mg treatment (NASA2 [Nexium Anti-inflammatory Symptom Amelioration] and SPACE2 [Symptom Prevention by Acid Control with
Esomeprazole] studies; ClinicalTrials.gov identifiers NCT00241514 and NCT00241553, respectively) performed at various rheumatology,
gastroenterology, and primary care clinics. Four hundred and twenty-six patients completed the 6-month treatment period. The
primary measure was the proportion of patients with relapse of upper GI symptoms, recorded in daily diary cards, after 6 months.
Relapse was defined as moderate-to-severe upper GI symptoms (a score of more than or equal to 3 on a 7-grade scale) for 3
days or more in any 7-day period. Esomeprazole was significantly more effective than placebo in maintaining relief of upper
GI symptoms throughout 6 months of treatment. Life-table estimates (95% confidence intervals) of the proportion of patients
with relapse at 6 months (pooled population) were placebo, 39.1% (32.2% to 46.0%); esomeprazole 20 mg, 29.3% (22.3% to 36.2%)
(p = 0.006 versus placebo); and esomeprazole 40 mg, 26.1% (19.4% to 32.9%) (p = 0.001 versus placebo). Patients on either non-selective NSAIDs or selective COX-2 inhibitors appeared to benefit. The frequency
of adverse events was similar in the three groups. Esomeprazole maintains relief of NSAID-associated upper GI symptoms in
patients taking continuous NSAIDs, including selective COX-2 inhibitors. 相似文献