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   467篇
  免费   21篇
  国内免费   4篇
耳鼻咽喉   17篇
儿科学   4篇
妇产科学   23篇
基础医学   77篇
口腔科学   3篇
临床医学   47篇
内科学   103篇
皮肤病学   1篇
神经病学   53篇
特种医学   8篇
外科学   55篇
综合类   3篇
预防医学   13篇
眼科学   4篇
药学   41篇
中国医学   1篇
肿瘤学   39篇
  2023年   1篇
  2022年   5篇
  2021年   9篇
  2020年   6篇
  2019年   11篇
  2018年   11篇
  2017年   8篇
  2016年   13篇
  2015年   13篇
  2014年   16篇
  2013年   16篇
  2012年   29篇
  2011年   40篇
  2010年   21篇
  2009年   27篇
  2008年   38篇
  2007年   26篇
  2006年   26篇
  2005年   37篇
  2004年   33篇
  2003年   29篇
  2002年   19篇
  2001年   1篇
  1999年   4篇
  1998年   4篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1994年   4篇
  1993年   7篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1979年   2篇
  1978年   2篇
  1975年   1篇
  1974年   1篇
  1971年   1篇
  1968年   2篇
  1965年   1篇
排序方式: 共有492条查询结果,搜索用时 15 毫秒
1.
Using 32P-postlabeling we studied DNA adduct formation in HL-60 cells treated with the o-phenylphenol metabolites o-phenylhydroquinone (o-PHQ) and o-phenylbenzoquinone (o-PBQ). Treatment with 25-500 microM o-PHQ for 8 h produced one principal and three minor adducts with a relative distribution of 80, 10, 6 and 4%. The relative adduct levels from these treatments were 0.26-2.31 adducts/10(7) nucleotides. Treatment with 25-250 microM o-PBQ for 2 h resulted in a similar level of DNA modification and adduct distribution. Reaction of purified calf thymus DNA with o-PBQ produced one DNA adduct, which did not correspond to the major adduct produced in HL-60 cells. These results show that o-PHQ and o-PBQ can form DNA adducts. Peroxidase activation of o-phenylphenol may therefore play a role in the carcinogenic effect of this compound.  相似文献   
2.
BACKGROUND: Major depressive disorder (MDD) shows increased coronary artery disease (CAD) risk of unknown mechanism(s). MDD is more common in women than men; CAD diagnosis can be difficult in women. Elevations of the inflammatory markers C-reactive protein (CRP) and serum amyloid A (SAA) predict increased CAD risk in populations; few data on these markers exist in MDD, particularly in remitted patients. METHODS: We measured fasting am serum CRP (high sensitivity, CRP(hs)) and SAA in 18 unmedicated, remitted women with MDD (mean age 41 +/- (SD)12, body mass index (BMI) 25.2 +/- 4.1 kg/m(2)) and 18 BMI-matched healthy control subjects (age 36 +/- 10, BMI 25.3 +/- 3.8 kg/m(2)) on 2 separate occasions, > or = 6 days apart. RESULTS: Repeat SAA and CRP(hs) measurements strongly correlated across study days (SAA: r = .83, p < .001; CRP(hs): r = .94, p < .001). Both SAA (5.30 +/- 3.39 vs. 2.84 +/- 1.87 mg/L, p < .005) and CRP(hs) (3.23 +/- 3.17 vs. 1.12 +/- 1.45 mg/L; p < .01) were significantly elevated in MDD women versus controls. CONCLUSIONS: Elevated SAA and CRP(hs) in remitted, unmedicated women with MDD indicate a pro-inflammatory state unrelated to current depressive symptoms or pharmacotherapy. These findings suggest that inflammatory mechanisms may in part underlie findings of increased CAD risk in MDD.  相似文献   
3.
OBJECTIVE: Standard lung donor criteria have been established on opinions and individual experiences rather than on existing evidence. Since the scarcity of donor organs is one of the major limitations to lung transplantation, extension of donor lung criteria might considerably increase the donor pool. This study therefore evaluates the outcome, achieved with the use of extended donors versus standard donors and aims to redefine lung donor criteria. METHODS: We performed a retrospective analysis of 98 consecutive primary lung transplantations from 94 donors from 1/2001 to 12/2002. Donors were classified as extended if they fulfilled at least one criteria: age >55 years, PaO(2) at FiO(2)/PEEP 5 <300mmHg, tobacco history >20 pack years, inhalative drug abuse, presence of infiltration on chest X-ray or purulent secretions at bronchoscopy. Recipients were stratified in two groups according to whether they received a 'standard' or 'extended' organ. Postoperative complications, extubation time, ICU and hospital stay and survival were compared. RESULTS: Twenty-three (24.5%) donors were extended. Twenty-six recipients (26.55%) received organs from extended donors. Differences in intubation times (12+/-2 days standard vs. 14+/-5 days extended, P=0.70), ICU stay (16+/-2 days standard vs. 18+/-5 days extended, P=0.74) and hospital stay (38+/-4 days standard vs. 40+/-6 days extended, P=0.71) were not statistically significant. Postoperative bleeding rates were comparable (n=14 standard vs. n=3 extended) as well as bronchial anastomotic complications (n=7 standard vs. n=3 extended). Three months survival was 88.89% in the standard group vs. 92.31% in the extended group. One year survival is comparable as well with 81.94 vs. 84.62%, respectively. CONCLUSIONS: The use of lung donors who fail to meet standard criteria does not impair short and medium term results compared to standard lung donors. The impact on long term development of BOS has yet to be evaluated. The strict application of standard lung donor criteria excludes a considerable number of lungs potentially suitable for transplantation, thus liberalisation of donor criteria might help to overcome donor shortage.  相似文献   
4.
5.
6.
7.
It is well known that migraine has a strong genetic component, although the type and number of genes involved is not yet clear. There is evidence to suggest that serotonin-related genes participate in the pathogenesis of migraine. Previous studies have shown that gender differences influence the serotonergic neurotransmission and, in addition, the migraine prevalence is higher in females than males. Therefore, we investigated the functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) and the 102T/C polymorphism of the 5-HT2A receptor gene in the Hungarian female population. These genes were analysed in 126 migraine sufferers (with or without aura)and 101 unrelated healthy controls using case control design. A borderline association (chi2 = 3.84, df = 1, p = 0.049; OR = 1.45, 95% CI = 1.00-2.12) between 5-HTTLPR short (S) allele and migraine was found. No significant difference between migraine sufferers and controls was observed for the 102T/C polymorphism of 5-HT2A receptor gene. Furthermore, there was no significant interaction between5-HTTLPR and 102T/C polymorphisms in our study population. In conclusion, our results support that the genetic susceptibility of migraine may be associated with a locus at or near the 5-HT transporter gene.  相似文献   
8.
9.
Phenylketonuria (PKU) is a genetic disorder secondary to a deficiency of hepatic phenyalanine hydroxylase (PAH). Several mutations in thePAH gene have recently been reported, and linkage disequilibrium was observed between RFLP haplotypes and specific mutations. A new molecular lesion has been identified in exon 7 of thePAH gene in a Hungarian PKU patient by direct sequencing of PCR-amplified DNA. The C-to-T transition causes the substitution of Arg243 to a termination codon, and the mutant allele is associated with haplotype 4 of thePAH gene. The mutation is present in two of nine mutant haplotype 4 alleles among Eastern Europeans and is not present among Western Europeans and Asians. The rarity of this mutant allele and its restricted geographic distribution suggest that the mutational event occurred recently on a normal haplotype 4 background in Eastern Europe.  相似文献   
10.
Purpose To investigate possible relationships of interleukin-1 (IL-1, interleukin-6 (IL-6), and growth hormone (GH) with biochemical variables in human follicular fluid (FF) and selected in vitro fertilization (IVF) parameters.Methods A total of 67 FF samples (n=67 patients undergoing oocyte retrieval for IVF) was evaluated. IL-1, IL-6, GH, hLH, FSH, PRL, hCG, testosterone, total protein, fibrinogen, sialic acid, 1-antitrypsin, plasminogen levels, and spectrophotometric absorbance at 458 nm were analyzed for selected FF. IL-6 and GH levels of serum and FF samples were also compared (n=23).Results Immunoreactive levels of IL-1, IL-6, and GH were detected in all FF samples. A positive correlation existed for IL-6 (r=0.5069, P=0.0161 when serum-to-FF levels were compared (concentration ratio, 11.857). Smaller-volume follicles (<4 ml) were associated with high IL-1 levels (P=0.0229, and an additional tendency of IL-1 to decrease with increasing embryo cleavage and scoring was observed. With the exception of a weak positive correlation between follicular IL-1 and testosterone levels (r=0.3128, P=0.025, no other relationship with biochemical variables or IVF parameters (etiology, e.g., endometriosis) could be implicated.Conclusions Substantially higher IL-6 levels occurred in FF compared to serum, thus supporting intrafollicular production. Interleukin- 1,IL-6, and GH levels in FF are, however, unsuitable markers for in vitro fertilization outcome.  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