首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   316篇
  免费   10篇
  国内免费   3篇
耳鼻咽喉   5篇
儿科学   19篇
基础医学   28篇
口腔科学   8篇
临床医学   12篇
内科学   27篇
皮肤病学   5篇
神经病学   23篇
特种医学   1篇
外科学   14篇
综合类   30篇
预防医学   95篇
眼科学   3篇
药学   47篇
中国医学   7篇
肿瘤学   5篇
  2024年   1篇
  2023年   1篇
  2022年   3篇
  2021年   3篇
  2020年   3篇
  2019年   17篇
  2018年   12篇
  2017年   15篇
  2016年   2篇
  2015年   7篇
  2014年   18篇
  2013年   10篇
  2012年   24篇
  2011年   36篇
  2010年   9篇
  2009年   15篇
  2008年   13篇
  2007年   11篇
  2006年   12篇
  2005年   6篇
  2004年   7篇
  2003年   2篇
  2002年   5篇
  2001年   9篇
  2000年   5篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1996年   4篇
  1995年   2篇
  1994年   6篇
  1993年   4篇
  1992年   4篇
  1991年   1篇
  1990年   1篇
  1989年   3篇
  1988年   5篇
  1987年   2篇
  1986年   3篇
  1985年   8篇
  1984年   7篇
  1983年   6篇
  1982年   4篇
  1981年   3篇
  1980年   4篇
  1979年   4篇
  1978年   3篇
  1977年   2篇
  1971年   1篇
排序方式: 共有329条查询结果,搜索用时 250 毫秒
1.
BackgroundHeavy metal contamination has become a serious issue in this century especially detected in fish organs. Due to the presence of radioactive compounds in agricultural and sewage effluent, which destroys aquatic ecosystems, threatening human livelihoods. Health hazards associated with low and high consumption consumers assessed in five commercial fish species collected from Hurghada City, Egypt, during winter and summer, 2020. Atomic absorption spectrophotometer technique used for determination heavy meals in different organs and expressed as μg/g wet weight.ResultsHeavy metal concentrations in muscle ranged between:(0.054–0.109), (0.260–1.043), (0.264–0.897), (5.895–11.898), (0.381–0.970), (13.582–29.133) and (0.332–0.589) µg/g for Cd, Pb, Mn, Zn, Cu, Fe and Ni respectively, which were lower than those of gills and liver. These concentrations were within WHO, FAO/WHO, and EU standards. Consumption of edible species was lower than the (TDIs) established by the (JECFA) and Egyptian Standards. Even though THQ and TTHQ values were < 1 while, in children with highly consumer were> 1.ConclusionThis study concluded that intake of Red Sea fish is safe for human health. It is critical for consumers to be aware of the consequences of excessive fish consumption, particularly children with highly consumer, which represent possible health risks.  相似文献   
2.
HI6(pyridinium, 1-[[[4-(aminocarbonyl)pyridinio] methoxy]methyl]-2-[(hydroxyimino)methyl]-dichloride belongs to a series of bisquaternary pyridinium oximes that are effective against poisoning with extremely toxic organophosphates. Since HI6 has been shown to be unstable at pH 7.4 and to release significant amounts of cyanide, a study was undertaken to determine the degree of cyanide formation from HI 6 in vivo. When HI 6 (100 mol/kg) was administered i. v. to dogs, the animals showed no signs of cyanide toxicity but exhibited some cholinomimetic symptoms, including retching, hypersalivation and enhanced intestinal motility. Cyanide content in whole blood was monitored after production of methemoglobinemia (30%) by 4-dimethylaminophenol in order to sequester cyanide within red cells. Maximal cyanide contents of 20 mol/l were found in blood after 90 min. Calculation of the area under the concentration versus time curve for blood cyanide indicates that about 4% of HI 6 produced cyanide. Determination of the pharmacokinetic parameters of HI 6 (VD=0.31 l/kg; kel=0.76 h–1) and of cyanide (VD=0.086 l/kg; kel=0.52 h–1) together with the apparent first order rate constant of cyanide formation from HI 6 in vitro (0.174 h–1, pH 7.4, 37°) allowed the simulation of a cyanide concentration curve that fitted with the experimental data points, indicating that cyanide formation in vivo was not bio-catalyzed. It is concluded that cyanide formation from HI 6 may not be regarded as a potential hazard, since cyanide elimination exceeded markedly its formation. Whether this conclusion also holds true for man has to be established.  相似文献   
3.
HLö 7 dimethanesulfonate (1-[[[4-(aminocarbonyl)pyridinio] methoxy] methyl] -2,4-bis [(hydroxyimino) methyl]pyridinium dimethanesulfonate) is a broad-spectrum reactivator against highly toxic organophosphorus compounds. The compound was synthesized by a new route with the carcinogenic bis(chloromethyl)ether being substituted by the non-mutagenic bis(methylsulfonoxymethyl)ether. The very soluble dimethanesulfonate of obidoxime was also prepared by this way. HLö 7 dimethanesulfonate is the first water-soluble salt of HLö 7 that should be suitable for the wet/dry autoinjector technology, because aqueous solutions of HLö 7 are not very stable (calculated shelf-life 0.2 years when stored at 8°C, 1 M solution, pH 2.5). The crystalline preparation contains 96% of thesyn/syn-isomer, less than 2% of thesyn/anti-isomer and some minor identified by-products. HLö 7 was very efficient in reactivating acetylcholinesterase (AChE) blocked by organophosphates as long as ageing did not prevent dephosphylation. HLö 7 was superior to HI 6 (1-[[[4-(aminocarbonyl)pyridinio]methoxy]methyl]-2-[(hydroxyimino)methyl]pyridinium dichloride) in reactivating soman and sarin-inhibited AChE from erythrocytes, and literature data indicate that HLö 7 exceeds HI 6 by far in reactivating tabun-inhibited AChE. In atropine-protected, soman-poisoned mice HLö 7 was three times more potent than HI 6 (protective ratio 5 versus 2.5), and in sarin-poisoned mice HLö 7 was 10 times more potent than HI 6 (protective ratio 8 for both oximes). In atropine-protected guinea-pigs HLö 7 was less effective than HI 6 (protective ratio: 2.3 versus 5.2 for soman; 5.2 versus 6.8 for sarin; 4.3 versus 3.8 for tabun). The mean survival time of anaesthetized guinea-pigs exposed to 5 LD50 soman (6.3 min) was increased by atropine (27 min) and atropine + HLö 7 (57 min). HLö 7 alone did not prolong the survival. The most impressive effect of HLö 7 was on respiration: 3 min after i.v. injection of HLö 7 and atropine, the depressed respiration increased rapidly to 60% of control and remained at that level during the observation period (60 min). With atropine alone, respiration recovered only slowly. Behavioural and physiologic parameters were determined in atropine-protected mice exposed to a sublethal soman dose. The running performance was significantly improved by HLö 7. Even central symptoms, e.g. hypothermia and convulsions, were decreased markedly by HLö 7 (evaluation 60 min after poisoning). The pharmacokinetic data for HLö 7 in male beagle dogs are similar to those of HI 6. After i.v. injection: t1/2 = 5 min; t1/2ß = 46 min; VD = 0.24 1/kg; Clp1 = 3.7 ml x min–1 x kg–1; Clren= 3.2 ml x min–1 x kg–1; renal excretion of unchanged HLö 7 = 86%. After i. m. injection: t1/2abs = 14 min; t1/2ß = 48 min; Vd = 0.27 1/kg; Clp1= 3.9 ml x min–1 x kg–1; Clren= 2.7 ml x min–1 x kg–1; renal excretion of unchanged HLö 7 = 76%; bioavailability >95%. Plasma protein binding was <5%; HLö 7 did not permeate into red cells. A dose of 20 mol/kg was well tolerated both after i.v. and i.m. administration. In anaesthetized dogs (chloralose) HLö 7 i.v. (20 (imol/kg) showed marginal hypotensive effects, whereas 50 mol/kg resulted in decreased mean blood pressure (–15%) and blood flow (–30%) without reflex tachycardia. One out of four dogs developed a circulatory shock syndrome with anuria. Respiration varied only transiently. Blood gases and pH were not influenced. Similar cardiovascular effects were observed in anaesthetized (urethane) guinea-pigs. In isolated guinea-pig hearts (Langendorff) sinus and ventricular heart rate were not influenced by HLö 7 <500 M. HLö 7 antagonized both carbachol and nicotine effects. Red cell AChE was inhibited by HLö 7 by up to 50%; C50 about 100 M. Previously, HLö 7 was shown to block ganglionic transmission (IC50= 500 M), probably due to ion-channel blockade. These data indicate that HLö 7 combines ganglion blocking, anticholinergic and indirect cholinergic properties like other bispyridinium compounds. The results suggest that HLö 7 may be tolerated by man at a dose of 10 mol/kg. Vital functions are not expected to be impaired. At such a dose (250–500 mg), which can be injected by an autoinjector, HLö 7 is expected to be superior to HI 6.Part of thesis  相似文献   
4.
In Australia, during the 2010 Southern Hemisphere (SH) influenza season, there was an unexpected increase in post-marketing adverse event reports of febrile seizures (FS) in children under 5 years of age shortly after vaccination with the CSL 2010 SH trivalent influenza vaccine (CSL 2010 SH TIV) compared to previous CSL TIVs and other licensed 2010 SH TIVs. In an accompanying study, we described the contribution to these adverse events of the 2010 SH influenza strains as expressed in the CSL 2010 SH TIV using in vitro cytokine/chemokine secretion from whole blood cells and induction of NF-κB activation in HEK293 reporter cells. The aim of the present study was to identify the root cause components that elicited the elevated cytokine/chemokine and NF-κB signature. Our studies demonstrated that the pyrogenic signal was associated with a heat-labile, viral-derived component(s) in the CSL 2010 SH TIV. Further, it was found that viral lipid-mediated delivery of short, fragmented viral RNA was the key trigger for the increased cytokine/chemokine secretion and NF-κB activation. It is likely that the FS reported in children <5 years were due to a combination of the new influenza strains included in the 2010 SH TIV and the CSL standard method of manufacture preserving strain-specific viral components of the new influenza strains (particularly B/Brisbane/60/2008 and to a lesser extent H1N1 A/California/07/2009). These combined to heighten immune activation of innate immune cells, which in a small proportion of children <5 years of age is associated with the occurrence of FS. The data also demonstrates that CSL TIVs formulated with increased levels of splitting agent (TDOC) for the B/Brisbane/60/2008 strain can attenuate the pro-inflammatory signals in vitro, identifying a potential path forward for generating a CSL TIV indicated for use in children <5 years.  相似文献   
5.
《Vaccine》2015,33(24):2813-2822
BackgroundIn the first five I-MOVE (Influenza Monitoring Vaccine Effectiveness in Europe) influenza seasons vaccine effectiveness (VE) results were relatively homogenous among participating study sites. In 2013–2014, we undertook a multicentre case-control study based on sentinel practitioner surveillance networks in six European Union (EU) countries to measure 2013–2014 influenza VE against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. Influenza A(H3N2) and A(H1N1)pdm09 viruses co-circulated during the season.MethodsPractitioners systematically selected ILI patients to swab within eight days of symptom onset.We compared cases (ILI positive to influenza A(H3N2) or A(H1N1)pdm09) to influenza negative patients. We calculated VE for the two influenza A subtypes and adjusted for potential confounders. We calculated heterogeneity between sites using the I2 index and Cochrane's Q test. If the I2 was <50%, we estimated pooled VE as (1 minus the OR) × 100 using a one-stage model with study site as a fixed effect. If the I2 was >49% we used a two-stage random effects model.ResultsWe included in the A(H1N1)pdm09 analysis 531 cases and 1712 controls and in the A(H3N2) analysis 623 cases and 1920 controls. For A(H1N1)pdm09, the Q test (p = 0.695) and the I2 index (0%) suggested no heterogeneity of adjusted VE between study sites. Using a one-stage model, the overall pooled adjusted VE against influenza A(H1N1)pdm2009 was 47.5% (95% CI: 16.4–67.0).For A(H3N2), the I2 was 51.5% (p = 0.067). Using a two-stage model for the pooled analysis, the adjusted VE against A(H3N2) was 29.7 (95% CI: −34.4–63.2).ConclusionsThe results suggest a moderate 2013–2014 influenza VE against A(H1N1)pdm09 and a low VE against A(H3N2). The A(H3N2) estimates were heterogeneous among study sites. Larger sample sizes by study site are needed to prevent statistical heterogeneity, decrease variability and allow for two-stage pooled VE for all subgroup analyses.  相似文献   
6.
《Vaccine》2015,33(32):3947-3952
Commercial vaccines against avian influenza viruses (AIV) in chickens consist mainly of inactivated AIV, requiring parenteral administration and co-delivery of an adjuvant. Limitations in T helper 1 or T helper 2 biased responses generated by these vaccines emphasize the need for alternative, more efficacious adjuvants. The Toll-like receptor (TLR) 21 ligand, CpG oligodeoxynucleotides (ODN), has been established as immunomodulatory in chickens. Therefore, the objective of this study was to investigate the adjuvant potential of high (20 μg) and low (2 μg) doses of CpG ODN 2007 (CpG 2007) and CpG ODN 1826 (CpG 1826) when administered to chickens with a formalin-inactivated H9N2 AIV. Antibody responses in sera were evaluated in 90 specific pathogen free (SPF) chickens after intramuscular administration of vaccine formulations at 7 and 21 days post-hatch. Antibody responses were assessed based on haemagglutination inhibition (HI) and virus neutralization (VN) assays; virus-specific IgM and IgY antibody responses were evaluated by ELISA. The results suggest that the vaccine formulation containing low dose CpG 2007 was significantly more effective at generating neutralizing (both HI and VN) responses than formulations with high or low doses of CpG 1826 or high dose CpG 2007. Neutralizing responses elicited by low dose CpG 2007 significantly exceeded those generated by a squalene-based adjuvanted vaccine formulation during peak responses. A significantly higher IgM response was elicited by the formulation containing low dose CpG 2007 compared to high and low doses of 1826. Although the low dose of CpG 2007 elicited a higher IgY response than CpG 1826, the difference was not statistically significant. In conclusion, 2 μg of CpG 2007 is potentially promising as a vaccine adjuvant when delivered intramuscularly with inactivated H9N2 virus to chickens. Future studies may be directed at determining the mucosal antibody responses to the same vaccine formulations.  相似文献   
7.
Vibrio vulnificus, an opportunistic marine bacterium that causes a serious, often fatal, infection in humans, requires iron for its pathogenesis. This bacterium exports vulnibactin for iron acquisition from the environment. The mechanisms of vulnibactin biosynthesis and ferric-vulnibactin uptake systems have recently been reported, while the vulnibactin export system has not been reported. Mutant growth under low-iron concentration conditions and a bioassay of the culture supernatant indicate that the VV1_0612 protein plays a crucial role in the vulnibactin secretion as a component of the resistance-nodulation-division (RND)-type efflux system in V. vulnificus M2799. To identify which RND protein(s) together with VV1_0612 TolC constituted the RND efflux system for vulnibactin secretion, deletion mutants of 11 RND protein-encoding genes were constructed. The growth inhibition of a multiple mutant (Δ11) of the RND protein-encoding genes was observed 6 h after the beginning of the culture. Furthermore, ΔVV1_1681 exhibited a growth curve that was similar to that of Δ11, while the multiple mutant except ΔVV1_1681 showed the same growth as the wild-type strain. These results indicate that the VV1_1681 protein is involved in the vulnibactin export system of V. vulnificus M2799. This is the first genetic evidence that vulnibactin is secreted through the RND-type efflux systems in V. vulnificus.  相似文献   
8.
目的探讨心宝丸联合米力农治疗终末期心力衰竭的临床效果。方法选取2016年3月—2019年3月延安大学附属医院收治的96例终末期心力衰竭患者,随机分为对照组和治疗组,每组各48例。对照组静脉滴注米力农注射液,负荷量50μg/kg,缓慢静脉注射(10 min);继以0.50μg/(kg?min)静脉点滴维持,每日最大剂量不超过1.13 mg/kg。治疗组在对照组治疗基础上口服心宝丸,6丸/次,3次/d。两组均连续治疗5d。观察两组的临床疗效,比较两组治疗前后心功能指标、血流动力学指标、血清学指标和中性粒细胞(NEUT)与淋巴细胞(LYM)比值(NLR)的变化情况。结果治疗后,对照组和治疗组的总有效率分别是77.1%、91.7%,两组比较差异具有统计学意义(P0.05)。治疗后,两组左心室收缩、舒张末期内径(LVESD和LVEDD)值均显著小于治疗前,而左室射血分数(LVEF)值均显著增高,同组治疗前后比较差异有统计学意义(P0.05);治疗后,治疗组LVESD、LVEDD值低于对照组,而LVEF高于对照组,两组比较差异具有统计学意义(P0.05)。治疗后,两组每搏输出量(SV)、心脏收缩力指数(HI)均较治疗前显著增加,而舒张功能指数(O/C)、肺动脉楔压(PAWP)、总外周阻力(TPR)均显著减小,同组治疗前后比较差异有统计学意义(P0.05);治疗后,治疗组SV、HI值高于对照组,而O/C、PAWP、TPR值低于对照组,两组比较差异具有统计学意义(P0.05)。治疗后,两组血清B型利钠肽(BNP)、可溶性生长刺激表达基因2蛋白(s ST2)、C反应蛋白(CRP)、外周血NLR均较治疗前显著下降,同组治疗前后比较差异有统计学意义(P0.05);治疗后,治疗组血清学指标和NLR均显著低于对照组,两组比较差异具有统计学意义(P0.05)。结论心宝丸联合米力农治疗终末期心力衰竭具有较好的临床疗效,有助于逆转患者心室重塑,增强心脏功能,改善血流动力学状态,减轻机体炎症反应,具有一定的临床推广应用价值。  相似文献   
9.

Purpose

To determine developmental outcomes and associated factors in patients with congenital diaphragmatic hernia (CDH) at 2 years of age.

Methods

This is a multicenter prospective study of a CDH birth cohort. Clinical and socioeconomic data were collected. Bayley Scales of Infant Development (BSID-III) and Vineland Adaptive Behavior Scales (VABS-II) were performed at 2 years of age.

Results

BSID-III and VABS-II assessments were completed on 48 and 49 children, respectively. The BSID-III mean cognitive, language, and motor scores were significantly below the norm mean with average scores of 93 ± 15, 95 ± 16, and 95 ± 11. Ten percent (5/47) scored more than 2 standard deviations below the norm on one or more domains. VABS-II scores were similar to BSID-III scores with mean communication, daily living skills, social, motor, adaptive behavior scores of 97 ± 14, 94 ± 16, 93 ± 13, 97 ± 10, and 94 ± 14. For the BSID-III, supplemental oxygen at 28 days, a prenatal diagnosis, need for extracorporeal membrane oxygenation (ECMO) and exclusive tube feeds at time of discharge were associated with lower scores. At 2 years of age, history of hospital readmission and need for tube feeds were associated with lower scores. Lower socioeconomic status correlated with lower developmental scores when adjusted for significant health factors.

Conclusion

CDH patients on average have lower developmental scores at 2 years of age compared to the norm. A need for ECMO, oxygen at 28 days of life, ongoing health issues and lower socioeconomic status are factors associated with developmental delays.  相似文献   
10.
We conducted a randomized, controlled, multicenter, phase II study to evaluate the immunogenicity and safety of an investigational intradermal (ID) trivalent influenza vaccine (TIV) and a high-dose (HD) intramuscular (IM) TIV in older adults (≥65 years of age). Older adult subjects were immunized with ID vaccine containing either 15 μg hemagglutinin (HA)/strain (n = 636) or 21 μg HA/strain (n = 634), with HD IM vaccine containing 60 μg HA/strain (n = 320), or with standard-dose (SD) IM vaccine (Fluzone®; 15 μg HA/strain; n = 319). For comparison, younger adults (18–49 years of age) were immunized with SD IM vaccine. In older adults, post-vaccination geometric mean titers induced by the ID vaccines were superior to those induced by the SD IM vaccine for the A/H1N1 and A/H3N2 strains and non-inferior for the B strain. Seroconversion rates induced by the ID vaccines were superior to those induced by the SD IM vaccine in older adults for the A/H1N1 and B strains and non-inferior for the A/H3N2 strain. Results did not differ significantly for the two ID vaccine dosages. Post-vaccination geometric mean titers, seroconversion rates, and most seroprotection rates were significantly higher in HD vaccine recipients than in older adult recipients of the SD IM or ID vaccines and, for most measures, were comparable to those of younger adult SD IM vaccine recipients. Injection-site reactions, but not systemic reactions or unsolicited adverse events, were more common with the ID vaccines than with the IM vaccines. No treatment-related serious adverse events were reported. This study demonstrated that: (1) the ID and HD vaccines were well-tolerated and more immunogenic than the SD IM vaccine in older adults; (2) the HD vaccine was more immunogenic than the ID vaccines in older adults; and (3) the HD vaccine in older adults and the SD IM vaccine in younger adults elicited comparable antibody responses (ClinicalTrials.gov identifier no.: NCT00551031).  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号