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   1960篇
  免费   132篇
  国内免费   3篇
耳鼻咽喉   11篇
儿科学   79篇
妇产科学   32篇
基础医学   287篇
口腔科学   40篇
临床医学   241篇
内科学   415篇
皮肤病学   30篇
神经病学   242篇
特种医学   92篇
外科学   255篇
综合类   6篇
一般理论   1篇
预防医学   127篇
眼科学   50篇
药学   99篇
肿瘤学   88篇
  2023年   30篇
  2022年   57篇
  2021年   107篇
  2020年   57篇
  2019年   93篇
  2018年   101篇
  2017年   72篇
  2016年   80篇
  2015年   103篇
  2014年   129篇
  2013年   141篇
  2012年   179篇
  2011年   161篇
  2010年   87篇
  2009年   72篇
  2008年   77篇
  2007年   73篇
  2006年   70篇
  2005年   55篇
  2004年   50篇
  2003年   43篇
  2002年   39篇
  2001年   14篇
  2000年   7篇
  1999年   6篇
  1998年   7篇
  1997年   5篇
  1996年   6篇
  1993年   5篇
  1992年   5篇
  1991年   5篇
  1990年   6篇
  1989年   5篇
  1988年   7篇
  1987年   7篇
  1986年   7篇
  1983年   5篇
  1981年   5篇
  1980年   7篇
  1979年   11篇
  1978年   4篇
  1977年   5篇
  1976年   5篇
  1975年   6篇
  1974年   12篇
  1973年   15篇
  1972年   10篇
  1971年   7篇
  1970年   8篇
  1969年   5篇
排序方式: 共有2095条查询结果,搜索用时 171 毫秒
1.
Recent years have brought an enhanced understanding of keratinocyte contribution to cutaneous nociception. While intra‐epidermal nerve endings were classically considered as the exclusive transducers of cutaneous noxious stimuli, it has now been demonstrated that epidermal keratinocytes can initiate nociceptive responses, like Merkel cells do for the innocuous mechanotransduction. In the light of recent in vivo findings, this article outlines this paradigm shift that points to a not yet considered population of sensory epidermal cells.  相似文献   
2.

Background

Refractory acute myeloid leukemia (AML) includes AML includes failure of disease to respond to standard induction chemotherapy, relapse within 6 months after first CR, and 2 or more relapses. The outcome of these patients is usually very poor; only a small proportion can be rescued by allogenic hematopoietic stem-cell transplantation (allo-HSCT). The aim of this study was to evaluate the efficacy and feasibility of allo-HSCT in patients with refractory AML.

Patients and Methods

We retrospectively analyzed the clinical outcome of 91 patients who were diagnosed with treatment-refractory AML at Hacettepe University Hospital between January 2002 and June 2018. Patients' disease status included refractory AML, defined as failure to respond to standard induction chemotherapy and relapse within 6 months after first complete remission.

Results

The median follow-up was 12 months (range, 0.5-184 months) for the entire group. Kaplan-Meier estimates of the 3-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 67% and 12%, respectively. Additionally, the Kaplan-Meier estimates of 5-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 44% and 4%, respectively (P < .001). Complete remission was obtained in 25 patients (83.3%) who underwent allo-HSCT; however, the disease of only 3 patients (3.8%) exhibited complete response after salvage chemotherapy.

Conclusion

Allo-HSCT is still the best-known treatment option with curative potential in patients with treatment-refractory AML. Therefore, all efforts should be made in an attempt to find a suitable matched donor in order to perform allo-HSCT.  相似文献   
3.
4.
Three cases of acrocephalosyndactyly with duplication of the first toe and presence of six well-individualized metatarsals are reported. This type of polysyndactyly should suggest the diagnosis of Carpenter syndrome, which is inherited on a recessive autosomal basis. However, in the three patients reported here, the facial dysmorphism was distinct from that seen in Carpenter syndrome and the syndactyly was more marked. The correct diagnosis therefore seems to be Apert acrocephalosyndactyly, a disease with dominant transmission. A mutation seems very likely and consequently the risk of recurrence in siblings is probably minimal.  相似文献   
5.
Effectiveness of gentamicin-impregnated cement in preventing deep wound infection after total knee arthroplasty (TKA) was estimated using data from prospective surveillance. In multivariate analysis, the protective effect of gentamicin-impregnated cement on the development of infection was close to the limit of significance. Gentamicin-impregnated cement may prevent TKA infections.  相似文献   
6.
INTRODUCTION: Spinal cord compression due to meningeal thickening is a rare occurrence in shunted patients. Because of the long delay to clinical onset, this complication has not been identified as yet. AIMS: We report on nine cases of shunt-related progressive myelopathy due to meningeal thickening (SPMMT). MATERIALS AND METHODS: We reviewed our database of shunted children, for cases having developed progressive tetraparesis due to cervical meningeal thickening. RESULTS: We identified nine observations of SPMMT, eight of these with hydrocephalus due to neonatal meningitis; the last case had Dandy-Walker malformation shunted at birth and suffered postoperative meningitis. The age of clinical onset of myelopathy was between 6 and 20 years (median 12.8). All patients presented with slowly progressive walking difficulties with falls and no spinal pain. Magnetic resonance imaging (MRI) showed typically a thickened dura mater with collapse of the arachnoid space, compensatory expansion of the epidural fat, and T2 hyperintensity in the spinal cord. We operated on seven patients for surgical decompression and arachnoidolysis: One died postoperatively because of shunt malfunction, and two others died later of complications of tetraplegia. Three patients were aggravated after surgery, three experienced partial improvement, but one of these subsequently deteriorated again. CONCLUSION: SPMMT appears to be a novel and well-defined clinical and pathological entity; its pathological and radiological features are stereotyped; however, the diagnosis is delayed because of the slow pace of the disease. Although surgical decompression may be the only option, its results were poor in our experience; earlier surgery might improve this grim prognosis.  相似文献   
7.
Aluminium has recently been considered as a causative agent in dialysis encephalopathy, osteodystrophy, and anemia occuring in hemodialysis patients. The aim of this study is to prepare magnetic poly(2-hydroxyethylmethacrylate) (mPHEMA) adsorbent and to investigate it's useability for the removal of Al(III) ions from drinking and dialysis water. Magnetic PHEMA beads in a size range 80-120 microm were produced by a dispersion polymerization technique. Then Alizarin Red was covalenlty attached onto the mPHEMA beads. Al(III) adsorption from aqueous solutions was examined by batch system. mPHEMA beads were characterized by swelling tests, electron spin resonance (ESR), scanning electron microscopy (SEM), and elemental analysis. Important results obtained in this study are as follows: the swelling ratio of mPHEMA beads was 34%. The presence of magnetite in the polymeric structure was confirmed by ESR. The mPHEMA beads have a spherical shape and porous structure. Alizarin Red loading was 135.8 micromol g(-1) polymer. The maximum Al(III) adsorption was 722 micromol g(-1) polymer at pH 5.0. Non-specific Al(III) adsorption was about 23 micromol g(-1) polymer under the same conditions. High desorption ratios (98%) were achieved by using 0.1 M HNO3. It was possible to reuse the beads without significant loss of Al(III) adsorption capacity.  相似文献   
8.
BACKGROUND: Chest radiography (CXR) is frequently performed in Western societies. There is insufficient knowledge of its diagnostic value in terms of changes in patient management decisions in primary care. AIM: To assess the influence of CXR on patient management in general practice. DESIGN OF STUDY: Prospective cohort study. SETTING: Seventy-eight GPs and three general hospitals in the Netherlands. METHOD: Patients (n = 792) aged > or =18 years referred by their GPs for CXR were included. The main outcome was change in patient management assessed by means of questionnaires filled in by GPs before and after CXR. RESULTS: Mean age of the patients was 57.3+/-16.2 years and 53% were male. Clinically relevant abnormalities were found in 24% of the CXRs. Patient management changed in 60% of the patients following CXR. Main changes included: fewer referrals to a medical specialist (from 26 to 12%); reduction in initiation or change in therapy (from 24 to 15%); and more frequent reassurance (from 25 to 46%). However, this reassurance was not perceived as such in a quarter of these patients. A change in patient management occurred significantly more frequently in patients with complaints of cough (67%), those who exhibited abnormalities during physical examination (69%), or those with a suspected diagnosis of pneumonia (68%). CONCLUSION: Patient management by the GP changed in 60% of patients following CXR. CXR substantially reduced the number of referrals and initiation or change in therapy, and more patients were reassured by their GP. Thus, CXR is an important diagnostic tool for GPs and seems a cost-effective diagnostic test.  相似文献   
9.
BACKGROUND: Quantification of HIV-1 RNA remains difficult to implement in Africa. Simple and inexpensive tests for antiretroviral treatment (ART) monitoring are needed. OBJECTIVE: To evaluate an HIV-1 p24 ELISA, which combines efficient virus disruption, heat-denaturation and signal amplification, in a West African setting. STUDY DESIGN: Eighty-six HIV-1 infected patients from Abidjan, C?te d'Ivoire, were tested for p24, HIV-1 RNA, and CD4+ count at baseline, and twice within 8 months after ART initiation. RESULTS: All patients responded to ART with a minimal HIV-1 RNA drop of 0.5 log(10) at first follow-up. Forty-one (47.7%) then rebounded >0.5 log(10) or persisted above 1000 copies/mL by week 24. The predicted baseline concentration of p24 corresponding to 100,000 copies/mL of HIV-1 RNA, above which ART is recommended, was 4546 fg/mL (95% confidence interval 3148-6566). A prediction model of virologic failure, occurring after an initial response to ART, correctly classified 84% of patients using baseline p24, p24 change on therapy, and achievement of undetectable p24 as explanatory variables. The model and further bootstrap evaluation suggested a good ability to discriminate between sustained or failing virologic response to ART. CONCLUSION: HIV-1 p24 and RNA based-ART monitoring in a low-resource country dominated by HIV-1 CRF02 AG appeared comparable.  相似文献   
10.
The changes in the autofluorescence characteristics of the bronchial tissue is of crucial interest as a cancer diagnostic tool. Evidence exists that this native fluorescence or autofluorescence of bronchial tissues changes when they turn dysplastic and to carcinoma in situ. There is good agreement that the lesions display a decrease of autofluorescence in the green region of the spectrum under illumination with violet-light, and a relative increase in the red region of the spectrum is often reported. Imaging devices rely on this principle to detect early cancerous lesions in the bronchi. Based on a spectroscopic study, an industrial imaging prototype is developed to detect early cancerous lesions in collaboration with the firm Richard Wolf Endoskope GmbH, Germany. A preliminary clinical trial involving 20 patients with this spectrally optimized system shows that the autofluorescence can help to detect most lesions that would otherwise have remained invisible to an experienced endoscopist under white light illumination. A systematic off line analysis of the autofluorescence images pointed out that real-time decisional functions can be defined to reduce the number of false positive results. Using this method, a positive predictive value (PPV) of 75% is reached using autofluorescence only. Moreover, a PPV of 100% is obtained, when combining the white light (WL) mode and the autofluorescence (AF) mode, at the applied conditions. Furthermore, the sensitivity is estimated to be twice higher in the AF mode than in WL mode.  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