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   726篇
  免费   43篇
  国内免费   2篇
耳鼻咽喉   11篇
儿科学   26篇
妇产科学   8篇
基础医学   108篇
口腔科学   25篇
临床医学   53篇
内科学   208篇
皮肤病学   27篇
神经病学   64篇
特种医学   16篇
外科学   82篇
预防医学   52篇
眼科学   8篇
药学   29篇
肿瘤学   54篇
  2023年   1篇
  2022年   11篇
  2021年   30篇
  2020年   13篇
  2019年   26篇
  2018年   19篇
  2017年   11篇
  2016年   16篇
  2015年   25篇
  2014年   27篇
  2013年   45篇
  2012年   51篇
  2011年   57篇
  2010年   35篇
  2009年   29篇
  2008年   41篇
  2007年   38篇
  2006年   56篇
  2005年   53篇
  2004年   54篇
  2003年   39篇
  2002年   26篇
  2001年   2篇
  2000年   6篇
  1999年   7篇
  1998年   4篇
  1997年   8篇
  1996年   10篇
  1995年   5篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1977年   1篇
  1947年   1篇
排序方式: 共有771条查询结果,搜索用时 31 毫秒
31.
32.
Reproducible fractures of the midshaft of the clavicle were created in 14 fresh frozen human cadaveric clavicles. Under the three-point bending loading by a materials testing machine, the load to failure of fixation of the clavicular fractures treated with steel reconstruction plates (five specimens) and Herbert cannulated bone screw (nine specimens), was compared with a group control formed by five specimens of clavicles without osteosynthesis material. No statistically significant differences were observed between the three groups. In consequence and in terms of biomechanics, in clavicular acute fractures, both plating and intramedullary Herbert cannulated bone screw may be utilized in the treatment of these lesions.  相似文献   
33.
PURPOSE: To determine the prevalence of psychiatric disorders during hospitalization for hematopoietic stem-cell transplantation (SCT) and to estimate their impact on hospital length of stay (LOS). PATIENTS AND METHODS: In a prospective inpatient study conducted from July 1994 to August 1997, 220 patients aged 16 to 65 years received SCT for hematologic cancer at a single institution. Patients received a psychiatric assessment at hospital admission and weekly during hospitalization until discharge or death, yielding a total of 1,062 psychiatric interviews performed. Psychiatric disorders were determined on the basis of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Univariate and multivariate linear regression analyses were used to identify variables associated with LOS. RESULTS: Overall psychiatric disorder prevalence was 44.1%; an adjustment disorder was diagnosed in 22.7% of patients, a mood disorder in 14.1%, an anxiety disorder in 8.2%, and delirium in 7.3%. After adjusting for admission and in-hospital risk factors, diagnosis of any mood, anxiety, or adjustment disorder (P =.022), chronic myelogenous leukemia (P =.003), Karnofsky performance score less than 90 at hospital admission (P =.025), and higher regimen-related toxicity (P <.001) were associated with a longer LOS. Acute lymphoblastic leukemia (P =.009), non-Hodgkin's lymphoma (P =.04), use of peripheral-blood stem cells (P <.001), second year of study (P <.001), and third year of study (P <.001) were associated with a shorter LOS. CONCLUSION: Our data indicate high psychiatric morbidity and an association with longer LOS, underscoring the need for early recognition and effective treatment.  相似文献   
34.
In the present study, the acute toxicity of 10 polycyclic aromatic hydrocarbons (PAHs) associated with the Prestige fuel oil spill (Spain, 2002) were evaluated, either as single substances or in mixtures, in adults of the copepod Oithona davisae. All but dimethylphenanthrene had negative effects on O. davisae survival at concentrations below their water solubility, with 48-h median lethal concentrations for naphthalene and pyrene of 56.1 and 0.8 micromol/L, respectively, making these the least and most toxic compounds. Polycyclic aromatic hydrocarbons had narcotic effects on copepods, as evidenced by the lack of motility at lower concentrations than those causing death. Naphthalene showed the greatest narcotic effects, and phenanthrene showed minor effects. Acute toxicity of the tested PAHs was inversely related (r2 = 0.9) with their octanol-water partition coefficient, thereby confirming the validity of the baseline quantitative structure-activity regression models for predicting the toxicity of PAH compounds in copepod species. When supplied in mixtures, the toxic effect of PAHs was additive. These results indicate that the many PAHs in an oil spill can be considered unambiguous baseline toxicants (class 1) acting additively as nonpolar narcotics in copepods; hence, their individual and combined toxicity can be predicted using their octanol-water partition coefficient.  相似文献   
35.
Several techniques have been advocated for knee arthrodesis, and there has been an increasing interest in modular intramedullary nails in the recent last years. We report a case of femoral and tibial fractures at each end of a modular nail in a solidly fused knee 8 months after an arthrodesis.  相似文献   
36.
INTRODUCTION: Histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto's disease is a rare anatomoclinical entity whose etiology remains unknown. It is mainly reported in young adult female, presenting with cervical lymphadenopathies, fever and asthenia. The diagnosis is based on the histological examination of a lymph node biopsy. The disease course is usually uneventful, but sometimes Kikuchi-Fujimoto's disease can reveal or evolve into a cutaneous or a systemic lupus. EXEGESIS: We report three new cases of Kikuchi's disease: the first one mimicked a systemic lupus, the second one was associated with a lupus-like rash, and a the last one was a severe case with hemophagocytic syndrome and a primo-infection with Epstein-Barr virus revealing a systemic lupus erythematosus. CONCLUSION: Clinical and biological follow-up of patients presenting with Kikuchi's disease is necessary to look for an association with a lupus. We discuss the pathogenic links between Kikuchi's disease and lupus.  相似文献   
37.
Gestational age and neonatal anthropometric parameters are currently used to evaluate fetal growth and are predictive factors of perinatal and postnatal morbidity and mortality. We performed a retrospective analysis of neonatal anthropometric parameters (weight, vertex-heel length and head circumference) in 1,470 live preterm neonates born between 1997 and 2002 and a prospective analysis of the same parameters in 1,786 live newborns of both sexes born in 2001 and 2002, products of single 37-42 week uncomplicated pregnancies in healthy Spanish Caucasian mothers. A progressive increase in these parameters with gestational age and sexual dimorphism were observed from the 30th week of gestational age onwards, with statistically-significant differences (p<0.05) at 38-42 weeks of gestational age. An increase in weight and length values in relation to previous Spanish studies was also documented in preterm newborns. It is estimated that 10-15% of children born small for gestational age (SGA) do not experience catch-up growth by the age of 3 years and may have short stature in adulthood. Preliminary data of a cross-sectional study on spontaneous growth in boys and girls born SGA without postnatal catch-up growth show that their +2 SD values of height are similar to -2 SD values of our normal control population of children born with adequate weight and length for gestational age (AGE). However, weight +2 SD values are similar to mean values of control children born AGE. In summary, our data show sexual dimorphism in neonatal anthropometric growth parameters and that these parameters change with time and may be updated. In addition children born SGA without postnatal catch-up are shorter and have higher weight than age-, height- and sex-matched controls born AGE.  相似文献   
38.
OBJECTIVE: To characterize a complex chromosome rearrangement (CCR) previously detected by G-banding in peripheral blood lymphocytes, as 46,X,-2,-11,-22,-X,+mar 1+mar2+mar3+mar4 in a patient with primary amenorrhea. DESIGN: Case report. SETTING: University faculty of Medicine and hospital. PATIENT(S): A 36-year-old woman with primary amenorrhea. INTERVENTION(S): Fluorescence in situ hybridization (FISH). MAIN OUTCOME MEASURE(S): Use of commercially available M-FISH probe (24 colors simultaneously) and whole chromosome painting probes for chromosomes 2, 11, 22, and X to characterize the CCR. RESULT(S): The use of conventional and multiple FISH allowed the redefinition of the CCR, showing a cryptic insertion of chromosome 11 in marker 3 previously suspected by M-FISH. The combination of G-banding and FISH data revealed that four chromosomes and seven breakpoints, including 2q21, 2q31, 11q22.1, 11q22.3, 22q13.3, Xp11.21, and Xq24, were implicated in this CCR. CONCLUSION(S): This report confirms the importance of a combination of G-banding and FISH (M-FISH and conventional FISH) techniques to characterize the de novo CCR. These techniques also were useful in defining two possible critical chromosome regions, Xp11.21 and Xq24, in which genes of potential interest for a primary amenorrhea could be located.  相似文献   
39.
BACKGROUND: Preservation injury is a major cause of primary graft dysfunction in liver transplantation (LT). Oxidative damage is considered to be the first event leading to graft damage. Xanthine oxidoreductase (XOR) and neutrophil activation, two sources of reactive oxygen species, could play a role in the development of graft dysfunction. METHODS: We determined activities of XOR forms, polymorphonuclear elastase (PMN-E), aminotransferases, and hyaluronic acid in plasma of 20 patients undergoing LT. Samples were taken from the radial artery (RA) before the anhepatic phase; from the portal vein (PV) before reperfusion; from graft caval effluent (CE) at reperfusion; and from RA, PV, and the hepatic vein (HV) 10 and 90 min postreperfusion. RESULTS: The graft, but not recipient bowel, released XOR into blood (XOR in CE, median, 61.2 mU/g protein [range, 1.9-160.4 vs. undetectable in PV before reperfusion). Circulating XOR was transformed from dehydrogenase to reversible oxidase (XOrev) (XOrev-to-XOR ratio, 48.1% in CE and 65.1% in HV 90 min postreperfusion). Neutrophil activation was detected in the recipients before reperfusion, and in liver at early post-reperfusion (median PMN-E was 0.85 microg/g protein [range, 0.01-1.58] in RA before the anhepatic phase; 2.22 microg/g protein [range, 0.20-5.88] in PV prereperfu-sion; and 3.60 microg/g protein [range, 0.48-6.78] in HV 10 min postreperfusion). XOR, but none of the other markers, was higher in the CE of patients with moderate primary graft dysfunction than in those with slight primary graft dysfunction. CONCLUSIONS: XOR release and neutrophil activation are produced during LT, and they are potentially injurious mechanisms associated with this therapy.  相似文献   
40.
Elevated levels of matrix metalloproteinase-9 (MMP-9) associates with predictors of multiple sclerosis (MS) activity. We analysed serum levels and mRNA expression of MMP-9 and its inhibitor TIMP-1 in peripheral mononuclear cells of 14 MS patients after autologous hematopoietic stem cell transplantation (AHSCT). All but 2 patients stabilized after AHSCT. A significant decrease of MMP-9 levels was seen up to 36 months after AHSCT. TIMP-1 levels did not change. MMP-9 mRNA levels correlated with the CD4+ T cell count (p<0.0001). The significant and persistent change in MMP-9 activity after AHSCT may be caused in part by the effect of AHSCT in the CD4+ T cell count.  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