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   735篇
  免费   47篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   14篇
妇产科学   64篇
基础医学   115篇
口腔科学   2篇
临床医学   103篇
内科学   120篇
皮肤病学   114篇
神经病学   15篇
特种医学   15篇
外科学   70篇
综合类   4篇
预防医学   33篇
眼科学   6篇
药学   62篇
中国医学   1篇
肿瘤学   43篇
  2021年   11篇
  2020年   8篇
  2019年   9篇
  2018年   14篇
  2017年   6篇
  2016年   13篇
  2015年   10篇
  2014年   13篇
  2013年   29篇
  2012年   58篇
  2011年   63篇
  2010年   39篇
  2009年   37篇
  2008年   32篇
  2007年   30篇
  2006年   37篇
  2005年   29篇
  2004年   28篇
  2003年   42篇
  2002年   40篇
  2001年   33篇
  2000年   22篇
  1999年   20篇
  1998年   8篇
  1997年   9篇
  1996年   9篇
  1995年   7篇
  1994年   4篇
  1992年   4篇
  1991年   7篇
  1990年   6篇
  1989年   5篇
  1988年   6篇
  1987年   4篇
  1985年   2篇
  1984年   4篇
  1983年   4篇
  1982年   6篇
  1981年   6篇
  1980年   11篇
  1979年   14篇
  1978年   5篇
  1977年   10篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1955年   2篇
  1954年   3篇
  1949年   2篇
排序方式: 共有783条查询结果,搜索用时 437 毫秒
1.
BACKGROUND: On December 26, 2004, the biggest earthquake for 40 years, measuring 9.0 on the Richter scale, triggered a tsunami that pounded the coastal areas of South Asia and East Africa. The effects of the tsunami on skin conditions have not been evaluated. OBJECTIVE: To determine the influence of the tsunami on skin conditions by evaluating the skin problems of patients presenting at hospitals after the tsunami. METHODS: Between 5 and 25 January 2005, two dermatologists evaluated patients who complained of skin problems at an outpatient clinic and emergency room of a general hospital in Banda Aceh, Aceh Province, Indonesia. RESULTS: The total number of patients that presented during the study period was 235 (131 males and 104 females), and they had a total of 265 skin problems. In terms of age distribution, most subjects were in their fourth decade (23.0%), followed by the third (22.6%) and fifth decade (16.6%). The most prevalent skin problems were infections-infestations (32.5%), followed by eczemas (29.8%) and traumatic skin disorders (29.4%). In males, traumatic skin disorders were most common. The great majority of infection-infestation cases involved superficial fungal infections. Contact dermatitis accounted for three-quarters of eczema cases, and mainly involved the arms (40.0%) and legs (27.1%). The majority of traumatic skin disorders were lacerations, punctures and penetrations, and the feet (44.7%) and hands (18.8%) were most frequently affected. CONCLUSIONS: Unhygienic conditions, exposure to a hazardous environment and contact with various objects during and after the tsunami probably increased the prevalence of infections-infestations, traumatic skin disorders and contact dermatitis. To prevent these problems and associated secondary bacterial infections, health-related education and early medical management are required.  相似文献   
2.
OBJECTIVE: To compare two published methods for determining plasma viraemia in HIV-seropositive patients, with reference to a cellular viraemia assay. PATIENTS, PARTICIPANTS: Three patient groups were defined according to CD4 cell count: group I, less than 200 x 10(6)/l (23 patients); group II, 200-500 x 10(6)/l (18 patients); and group III, greater than 500 x 10(6)/l (13 patients). METHODS: The two reported methodologies were applied to all fresh samples, simultaneously and on the same day. RESULTS: The two techniques did not differ significantly in the detection of plasma viraemia: 82.3% of group I patients and 55% of group II patients were positive, while all group III patients were negative. Cellular viraemia was positive for 96% of the overall population. CONCLUSIONS: These results, obtained in a network of seven French laboratories involved in clinical trials, confirm that both plasma viraemia and cellular viraemia are useful virological markers.  相似文献   
3.
SUMMARY The study explored the incidence of clinical feminisation and the sex hormone levels of 18 Nigerian patients with liver cirrhosis (LC) alone and 18 patients with LC and hepatocellular carcinoma (HCC). The incidence (11%) of clinical feminisation in Nigerian patients was lower than values reported from other countries and there was no association between feminising signs and the sex hormone levels of the patients. Plasma oestradiol and sex hormone-binding globulin (SHBG) levels were significantly higher and testosterone lower in patients with liver diseases than in 18 age-matched normal controls. Serum concentrations of oestradiol were also found to be significantly higher in patients with LC alone than in those with LC and HCC. A possible promotive role for oestrogens in the development of HCC from the cirrhotic liver is discussed.  相似文献   
4.
5.
Fiala  ES; Sohn  OS; Li  H; El-Bayoumy  K; Sodum  RS 《Carcinogenesis》1997,18(9):1809-1815
We observed that pretreatment of male F344 rats with benzyl selenocyanate, a versatile organoselenium chemopreventive agent in several animal model systems, decreases the levels of DNA and RNA modifications produced in the liver by the hepatocarcinogen 2- nitropropane. To clarify the mechanisms involved, we pretreated male F344 rats with either benzyl selenocyanate, its sulfur analog benzyl thiocyanate, phenobarbital or cobalt protoporphyrin IX; the latter is a depletor of P450. We then determined (1) the ability of liver microsomes to denitrify 2-nitropropane, (2) effects on 2-nitropropane- induced liver DNA and RNA modifications and (3) amount of nitrate excreted in rat urine following administration of the carcinogen. Pretreatment with benzyl selenocyanate or phenobarbital increased the denitrification activity of liver microsomes by 217 and 765%, respectively, increased liver P4502B1 by 31- and 435-fold, respectively, decreased the levels of 2-nitropropane-induced modifications in liver DNA (29-70% and 17-30%, respectively) and RNA (67-85% and 30-50%, respectively), and increased the 24-h urinary excretion of nitrate by 157 and 209%, respectively. Pretreatment with benzyl thiocyanate had no significant effect on any of these parameters. Pretreatment with cobalt protoporphyrin IX decreased liver P4502B 1 by 87%, decreased the denitrification activity of liver microsomes by 76%, decreased the 24 h urinary excretion of nitrate by 88.5%, but increased the extent of 2-nitropropane-induced liver nucleic acid modifications by 17-67%. These results indicate that the metabolic sequence from 2-nitropropane to the reactive species causing DNA and RNA modifications does not involve the removal of the nitro group. Moreover, they suggest that benzyl selenocyanate inhibits 2-NP-induced liver nucleic acid modifications in part by increasing its detoxication through induction of denitrification, although it is evident that other mechanisms must also be involved.   相似文献   
6.
The epicondylar axis is a reliable reference to check the rotation of the femoral implant in total knee prostheses (TKPs). However, during the operation it seems easier to use the posterior condylar axis as a landmark. The angle between these two axes is called the posterior condylar angle (PCA). The aim of this study was to measure the PCA in arthritic knees to assess the reliability of the posterior condylar axis as a reference for the control of the rotation of the femoral implant and to look for correlation with other radiological measurements. This prospective study consisted of 103 arthritic knees (81 varus, 22 valgus) before a TKP had been done in 103 patients (75 women, 28 men). The assessment of the PCA was made by computed tomographic scanning (CT). The HKA, HKS and HKT angles were measured on the pangonogram. The posterior condylar axis was internally rotated with respect to the epicondylar axis. The average value for all the patients was 2.65° degrees with a range from 0° to 7°. The PCA was significantly increased in the valgus knees. There was no correlation between the angles on the pangonogram and the posterior condylar axis. While the preoperative assessment of the PCA by CT scanning is reliable, the results obtained indicate the marked variability in its value. If one wishes to use the posterior condylar axis as a guide for rotation, it is therefore necessary to assess the PCA for each patient using adjustable jigs according to the value obtained. No measurement on standard radiographs allowed an extrapolation of the value of the PCA, and CT scanning seems to be the preferable radiological examination.

Electronic Supplementary Material The french version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer Link server located at
Etude tomodensitométrique de l'angle condylien postérieur dans les genoux arthrosiques. Intérêt dans le positionnement en rotation de l'implant fémoral dans les prothèses totales de genou
Résumé L'axe épicondylien est une référence fiable pour le contrôle de la rotation de l'implant fémoral dans les prothèses totales de genou (PTG). Mais, lors de l'intervention, il semble plus facile d'utiliser l'axe condylien postérieur comme repère. L'angle entre ses deux axes est appelé angle condylien postérieur (ACP). Le but de cette étude était de mesurer l'ACP dans les genoux arthrosiques, d'évaluer la fiabilité de l'axe condylien postérieur comme référence pour le réglage de la rotation de l'implant fémoral, de rechercher une corrélation avec d'autres mesures radiologiques. Une étude prospective comportant 103 genoux arthrosiques (81 varus et 22 valgus), avant PTG a été effectuée, chez 103 patients (75 femmes et 28 hommes). L'évaluation de l'ACP a été faite par examen tomodensitométrique (TDM). Les angles HKA, HKS et HKT ont été mesurés sur le pangonogramme. L'axe condylien postérieur était en rotation interne par rapport à l'axe épicondylien. La valeur moyenne pour tous les patients était de 2.65°, avec des valeurs de 0 à 7°. La valeur de l'angle CP augmentait avec une différence significative dans le groupe des genu valgum. Il n'y avait pas de corrélation entre les angles du pangonogramme et l'ACP. Si l'évaluation pré-opératoire de l'ACP par TDM est fiable, les résultats obtenus mettent en évidence une variabilité importante de sa valeur. Il faut donc, si l'on veut utiliser l'axe condylien postérieur comme repère de rotation, évaluer pour chaque patient l'ACP, et utiliser un ancillaire réglable reportant la valeur obtenue. Aucune mesure sur des radiographies standard ne permettant d'extrapoler la valeur de l'ACP, la TDM semble l'examen radiologique de choix.
  相似文献   
7.
8.
The authors studied the effect of zidovudine (ZDV) resistance mutation on virologic response to treatment with ZDV or stavudine (d4T) each in combination with lamivudine and indinavir. Viral genotyping was performed on plasma HIV-1 RNA at study entry and concerned 155 patients previously treated with ZDV, didanosine, or zalcitabine and enrolled in the NOVAVIR (Agence National de Recherche sur le SIDA [ANRS] 073) trial. Three virologic responses were investigated: early response (<50 copies/mL at week 24), late response (<500 copies/mL at week 80), and virologic failure (two HIV-1 RNA >5000 copies/mL). Patients were classified as resistant or susceptible to ZDV according to the ANRS algorithm. Plasma viral RNA from 123 of 155 patients had two or more ZDV resistance mutations. The number of ZDV resistance mutations was positively correlated with the duration of prior antiviral therapy (p <.001). At week 24, 74% and 77% of patients with virus classified as resistant were responders in the d4T and ZDV arm, respectively. Similar results were found at week 80. Virologic failure was reached in 7 of 24 patients with virus classified as susceptible and in 26 of 131 patients with resistant virus (p =.29). In the ZDV arm, patients classified as resistant had longer times to virologic failure than those classified as susceptible (p =.003). In conclusion, sustained virologic response despite presence of ZDV resistance mutations implies that these mutations do not preclude an early and durable response to treatment with a potent three-drug regimen in these patients. Patients susceptible to ZDV had lower median mean corpuscular volumes and lower random indinavir levels, suggesting that adherence was the main reason for failure.  相似文献   
9.
Human immunodeficiency virus type 2 (HIV-2) is much less pathogenic than HIV-1, and HIV-2 infection is associated with plasma viral loads significantly lower than those found in HIV-1 infection. We have developed a real-time quantitative PCR method for measuring the HIV-2 RNA load that covers the range of genetic diversity of HIV-2 isolates and that detects extremely low viral loads. Samples from 49 patients were studied. Proviral DNA was first detected and quantified. The strains that were detected were then genotyped: 21 patients were infected with HIV-2 subtype A and 15 patients were infected with HIV-2 subtype B; 1 patient was infected with a highly divergent strain. Env PCR failed for the remaining 12 patients, so subtypes could not be determined. For viral RNA quantification, a stock of HIV-2 strain NIHZ, which was counted by electron microscopy, was used as the standard. Several primer sets targeting the highly conserved gag region were evaluated. Various primer combinations failed to amplify subtype B strains. With the final primer pair selected, which detected both subtype A and subtype B strains, the sensitivity of the assay was 100% at a viral load of 250 copies/ml and 66% at a viral load of 125 copies/ml. We found a correlation between the CD4(+)-cell count, the clinical stage, and the plasma HIV-2 RNA level. The median plasma HIV-2 RNA value for the 33 asymptomatic patients was 2.14 log(10), whereas it was 3.1 log(10) for the 16 patients with AIDS (P < 0.01). Proviral DNA was detectable in 18 symptom-free patients with high CD4(+)-cell counts, in whom viral RNA was undetectable.  相似文献   
10.
Cell infiltration is commonly observed in human renal allograft biopsies. This infiltration was investigated using electron microscopy for a more precise assessment of the nature of these cells. More than 3000 cells infiltrating twenty-five renal allograft biopsies were studied. Six cellular types were distinguished and a mean percentage of each type was calculated. Only one-half of these cells were normal or transformed lymphocytes (including small lymphocytes: 22-3 +/- 3-8%, 'intermediary' cells: 22 +/- 3-6%, blast-like cells similar to MLC transformed lymphocytes: 8-1 +/- 2-4%. A relatively high number of plasmocytes (12-4 +/- 2-5%) and a still higher percentage of macrophages (28-5 +/- 4-6%) were found. Granulocytes represented only 2 +/- 0-8%of the cell population. Variations of the mean percentage of these cellular types were studied in various clinical situations.  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