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   2315篇
  免费   111篇
  国内免费   19篇
耳鼻咽喉   26篇
儿科学   25篇
妇产科学   140篇
基础医学   227篇
口腔科学   35篇
临床医学   185篇
内科学   586篇
皮肤病学   31篇
神经病学   154篇
特种医学   95篇
外科学   417篇
综合类   14篇
一般理论   1篇
预防医学   89篇
眼科学   61篇
药学   166篇
中国医学   3篇
肿瘤学   190篇
  2024年   1篇
  2023年   29篇
  2022年   59篇
  2021年   73篇
  2020年   46篇
  2019年   71篇
  2018年   76篇
  2017年   44篇
  2016年   64篇
  2015年   70篇
  2014年   107篇
  2013年   133篇
  2012年   197篇
  2011年   181篇
  2010年   110篇
  2009年   93篇
  2008年   186篇
  2007年   154篇
  2006年   165篇
  2005年   157篇
  2004年   109篇
  2003年   100篇
  2002年   76篇
  2001年   25篇
  2000年   35篇
  1999年   16篇
  1998年   12篇
  1997年   6篇
  1996年   6篇
  1995年   2篇
  1994年   13篇
  1993年   3篇
  1992年   6篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1972年   1篇
排序方式: 共有2445条查询结果,搜索用时 0 毫秒
11.
BACKGROUND: The use of immunosuppressive medication is a dominant risk factor for infection in patients with rheumatoid arthritis (RA). Methotrexate (MTX) is one of the traditional disease-modifying antirheumatic drugs. Adalimumab [a human anti-tumor necrosis factor-alpha (anti-TNF-alpha) monoclonal antibody] represent an important advance in the treatment of RA and has been recently come in use. TNF-alpha plays a role in the host defense against Mycobacterium tuberculosis and notably in granuloma formation. Infections occur at a high rate among those who use one or the combination of the two medications. METHOD: We examined a female patient that was referred to our department for evaluation and treatment of a granular lesion on the soft palate and uvula, complaining of mild dysphagia. The patient was treated for 4 months with MTX and adalimumab for RA before the oral lesion appeared. RESULTS: The histopathological examination of a specimen of the oral lesion, taken by biopsy, showed a chronic inflammation characterized by tuberculous granulomas. Polymerase chain reaction test and culture of a new specimen was positive for M. tuberculosis. CONCLUSIONS: The therapeutic use of MTX or/and adalimumab for the treatment of RA or few others diseases, can cause oral tuberculosis.  相似文献   
12.
BACKGROUND AND PURPOSE: Helical tomotherapy can eliminate the need for junction lines. The goal of this study is to evaluate tomotherapy in the delivery of CSA radiation and measurement of plan quality using physical parameters in comparing conventional (CSA-RT) and helical tomotherapy (CSA-TOMO) plans. PATIENTS AND METHODS: CSA-TOMO and CSA-RT plans were created for dosimetric comparison. Integral dose values were calculated. The ratios D50% (dose received by 50% of the organ at risk's volume) and D10% (dose received by 10% of the organ at risk's volume) were calculated representing large volumes and small volumes of organs at risk receiving significant dose. RESULTS: When considering D50% and D10%, CSA-TOMO has a dosimetric advantage over CSA-RT for most organs at risk. The body integral dose was higher for the CSA-TOMO plan by approximately 6.5%. CONCLUSIONS: Tomotherapy is a feasible alternative for treatment of CSA. Analysis shows that tomotherapy improves dose ratios over conventional radiation for most organs at risk. The impact of a small increase in whole body integral dose is unknown. Long-term follow-up will be needed to answer this question as others have argued of the possibility of increased risk of secondary malignancies due to delivery of radiotherapy with IMRT.  相似文献   
13.
14.
Reconstruction of large bony defects of long bones was performed using vascularised fibular grafts in four patients at the Department of Orthopaedic Surgery of the University of Ioannina Medical School. Indications for grafting procedures in this small series had been the loss of bone due to the extensive resection of avascular and necrotic bone from septic pseudoarthrosis in three patients and congenital pseudarthrosis secondary to neurofibromatosis in a child. Primary skeletal union with graft hypertrophy occurred in three of the patients. The fourth patient had an asymptomatic nonunion at the proximal end of the graft. The result in each patient was the presence of a well-aligned limb that had normal or nearly normal motion and acceptable length. © 1994 Wiley-Liss, Inc.  相似文献   
15.
BACKGROUND: Early color M-mode Doppler flow propagation (Ep) through the left ventricle (LV) has been proposed as a useful noninvasive index for assessing LV relaxation, whereas data concerning late velocity propagation (Ap) is lacking. METHODS: We studied 51 patients with delayed relaxation (group I) and 50 with pseudonormal filling pattern (group II). Another 51 aged-matched healthy persons served as the control group. RESULTS: Patients showed increased left atrial dimensions, atrial wave of the pulmonary vein flow, and Ap, and reduced LV ejection fraction, Ep, and Ep/Ap ratio compared with the control group. Patients in group II revealed increased left atrial dimensions (P =.001), atrial wave of the pulmonary vein flow (P <.001), and Ep/Ap ratio (P <.001), and reduced LV ejection fraction and Ap (P <.001) compared with group I. Regression analysis showed that the strongest independent variable distinguishing normal from pseudonormal filling pattern was the Ep/Ap ratio. CONCLUSION: Ap evaluation offers a new diagnostic diastolic index, especially in the field of the pseudonormal pattern where the separation from normal is difficult.  相似文献   
16.
17.
18.
The use of in vitro immunization technology for the generation of human antigen-specific antibodies has essentially resulted in low affinity IgM antibodies, resembling an in vivo primary immune response. We now describe a detailed reproducible protocol for a two-step in vitro immunization, which yields isotype switched, antigen-specific human antibodies. The immunizing antigen was a 30aa synthetic peptide, containing both a B (15aa V3 peptide of the HIV-1) and a T helper cell epitope (15aa peptide from tetanus toxin). The immunization protocol includes: (i) a selection procedure of donors with a memory T cell response against tetatus toxoid; (ii) immunization of mature naive peripheral B lymphocytes in two distinct phases, involving a primary and a secondary step. None of the donors which were examined after primary 7immunization showed at any time an IgG anti-V3 specific antibody response, while all the donors showed an IgM response. After the secondary immunization step, anti-V3 antibodies of both IgM and IgG isotypes were detected. The switch frequency event was high among the tested donors (5/8).  相似文献   
19.
SUMMARY: We studied the effect of haemodialysis on the serum levels of tumour markers in 78 patients, 49 men and 29 women with a mean age of 61 ± 2 years, who had been undergoing haemodialysis for 39 ± 10 months. No patient had any clinical evidence of malignancy. Serum values of carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), squamous-cell-carcinoma-related antigen (SCC), neuron-specific enolase (NSE), tissue polypeptide antigen (TPA), CA 15-3, CA 19–9, and among males prostate-specific antigen (PSA) were determined before and after dialysis. Postdialysis values, after being corrected for haemoconcentration, were compared with predialysis values. A significant increase of 32% was observed in NSE levels ( P <0.001) and of 21% in CA 15-3 ( P <0.001) after haemodialysis. A lesser, but still statistically significant, increase (8-12%) was observed in SCC, AFP and CEA levels ( P <0.05), while the values of the remaining three markers remained unchanged. In conclusion, an increase in some tumour markers was found in our patients after dialysis, a finding which requires further investigation.  相似文献   
20.

Background

Guidelines published in major medical journals are very influential in determining clinical practice. It would be essential to evaluate whether conflicts of interests are disclosed in these publications. We evaluated the reporting of conflicts of interest and the factors that may affect such disclosure in a sample of 191 guidelines on therapeutic and/or preventive measures published in 6 major clinical journals (Annals of Internal Medicine, BMJ, JAMA, Lancet, New England Journal of Medicine, Pediatrics) in 1979, 1984, 1989, 1994 and 1999.

Results

Only 7 guidelines (3.7%) mentioned conflicts of interest and all were published in 1999 (17.5% (7/40) of guidelines published in 1999 alone). Reporting of conflicts of interest differed significantly by journal (p=0.026), availability of disclosure policy by the journal (p=0.043), source of funding (p < 0.001) and number of authors (p=0.004). In the entire database of 191 guidelines, a mere 18 authors disclosed a total of 24 potential conflicts of interest and most pertained to minor issues.

Conclusions

Despite some recent improvement, reporting of conflicts of interest in clinical guidelines published in influential journals is largely neglected.
  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