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   45028篇
  免费   2710篇
  国内免费   258篇
耳鼻咽喉   388篇
儿科学   1296篇
妇产科学   1201篇
基础医学   5913篇
口腔科学   938篇
临床医学   4496篇
内科学   9830篇
皮肤病学   880篇
神经病学   4791篇
特种医学   1523篇
外科学   5908篇
综合类   175篇
一般理论   19篇
预防医学   3350篇
眼科学   767篇
药学   2774篇
  1篇
中国医学   85篇
肿瘤学   3661篇
  2024年   70篇
  2023年   520篇
  2022年   998篇
  2021年   1802篇
  2020年   1056篇
  2019年   1484篇
  2018年   1699篇
  2017年   1190篇
  2016年   1336篇
  2015年   1542篇
  2014年   2120篇
  2013年   2642篇
  2012年   3915篇
  2011年   3901篇
  2010年   1973篇
  2009年   1842篇
  2008年   3110篇
  2007年   3003篇
  2006年   2702篇
  2005年   2674篇
  2004年   2231篇
  2003年   1996篇
  2002年   1768篇
  2001年   226篇
  2000年   158篇
  1999年   231篇
  1998年   301篇
  1997年   222篇
  1996年   198篇
  1995年   181篇
  1994年   154篇
  1993年   122篇
  1992年   88篇
  1991年   79篇
  1990年   63篇
  1989年   42篇
  1988年   40篇
  1987年   35篇
  1986年   32篇
  1985年   31篇
  1984年   38篇
  1983年   19篇
  1982年   39篇
  1981年   24篇
  1980年   21篇
  1979年   9篇
  1978年   12篇
  1977年   12篇
  1976年   8篇
  1972年   8篇
排序方式: 共有10000条查询结果,搜索用时 5 毫秒
31.
Micrografting in the treatment of severely burned patients   总被引:4,自引:0,他引:4  
The micrografting technique, employed to treat patients with extensive TBSA burns and reduced areas of healthy donor skin, was assessed simultaneously with traditional mesh grafts (STSG) or Tiersch grafts in the treatment five severely burned subjects (average TBSA burned 35.6 per cent; average per cent of full thickness wounds 32.6 per cent).

At the first clinical control on day 6 post-surgery 93 per cent of the micrografted area was in situ and healthy: epithelialization of the wound sites was complete at day 21. Meshed STSG yielded 90 per cent attachment at day 6 post-surgery, with epithelialization complete at 12 ± 2 days post-surgery.

Functional results were equivalent no matter what technique was used, while aesthetic results were better in the areas where micrografting was carried out.

Although the micrograft technique is labour-intensive, if the expansion needed is at least 1:6, the aesthetic and functional results obtained are comparable to, or better than, those with meshed grafts. Also, large segments of micrograft are not compromised if a small area of mesh becomes detached, and epithelialization is faster and more uniform, enabling a reduction in both infection and length of hospital stay.  相似文献   

32.
The purpose of this study was threefold: to evaluate the role of gallium-67 scintigraphy in the staging of low-grade non-Hodgkin’s lymphomas (LGNHL), to assess the relationship between the expression of CD71 on the surface of the neoplastic cells and the 67Ga uptake by the tumour, and to establish the contribution of 67Ga scan in defining the prognosis of LGNHL. Forty-eight patients with untreated LGNHL diagnosed in a single institution over a decade were reviewed. The end point of the study was survival of the patients according to the scintigraphic 67Ga score at diagnosis. In addition to 67Ga scan, other prognostic variables were studied, relating to the neoplastic burden, the biology of the tumour and the host. Univariate and multivariate analyses were used. 67Ga scan identified only 116/286 (41%) nodes involved by lymphoma that were detected by clinical examination or computed tomography scan. A scintigraphic scoring system with an arbitrary cut-off value of 3 (high scan score) was able to predict patients with a dismal prognosis: with a mean follow-up of 47 months (range: 1–146 months) the median survival time was 28 months in patients with a high scan score and 74 months in patients with a low scan score (P=0.002). CD71 values were 27.4%±14.9% (mean ±SD) in the former and 8.9%±7.2% in the latter (P=0.0001). Only performance status and extranodal sites were significant variables for prognosis in multivariate analysis. It is concluded that 67Ga scan is inaccurate in staging but might be very important in defining the prognosis in LGNHL, in association with other prognostic variables. Received 1 May and in revised form 6 August 1997  相似文献   
33.
Lymph node (LN) metastases represent the most important negative prognostic factor in squamous cell carcinoma (SCC) of the oral cavity, even though controversies still exist regarding their management. The aim of this study was to retrospectively analyze our experience in surgical management of SCC of the oral cavity with particular focus on the prevalence and localization of lymph nodal metastases and recurrences. The clinical records of 89 consecutive patients treated from 1983 to 2002 by concomitant surgery on both the T and N sites, excluding those undergoing salvage surgery, were reviewed. A total of 119 neck dissections (ND) were performed. Survival outcomes were calculated by the Kaplan–Meier method, while univariate comparisons by the log-rank and non-parametric tests were performed between different groups of patients. Five-year overall and determinate survivals were 50 and 57%, respectively. LN metastases were observed in 52% (56% of these showing extracapsular spread) and their presence strongly correlated with determinate survival (p < 0.0001). The prevalence of clinical and occult nodal disease was not related to the pT status. Neck levels II (59%) and I (56%) were most frequently involved. Metastases to level IV accounted for 15% of positive LN, even though 28% of them turned out to be skip metastases. Five neck recurrences were observed, only one of which was salvaged by surgery. The high prevalence of clinical and occult LN metastases in this setting suggests that ND should be performed on a nearly routine basis, even for lesions with a low-T category and a cN0 neck. Moreover, ND should always encompass level IV due to the possibility of skip metastases, particularly in tumors involving the oral tongue. In patients with a cN+ neck, levels from I to V should be addressed, particularly in the presence of metastases at levels III and IV.  相似文献   
34.
Recurrent pleural effusions are common complications of hospitalized patients with human immunodeficiency virus (HIV) infection and may pose difficult diagnostic dilemmas. A common cause of recurrent pleural effusions in up to 30% of HIV-seropositive patients is pulmonary involvement by Kaposi's sarcoma, a human herpesvirus 8 (HHV 8)-related neoplasm. The pathogenesis of these effusions is unclear. These recurrent effusions, although benign, have shown significant mesothelial atypia/reactive changes of uncertain etiology. We attempted to evaluate these effusions morphologically and molecularly for the presence of HHV 8, with particular attention to mesothelial cells. All recurrent pleural effusions, as defined by any effusion tapped for cytological examination on more than two occasions, in HIV-positive patients at the National Institutes of Health were examined from 1998 to the present. Cases were stratified according to patients with and without histologically confirmed HHV 8 disease manifestations. Five patients with HHV 8 diseases (four with disseminated Kaposi's sarcoma and one with Castleman's disease) were identified. As a control group, five effusions from HIV-seropositive patients without known HHV 8-related diseases were identified. Cytological examination of effusions in patients with HHV 8-related diseases demonstrated atypical/markedly reactive mesothelial cells accompanied by a polymorphous background of lymphocytes. Molecular studies for B- and T-cell clonality in microdissected whole samples showed no definitive clones in these cases. Conversely, polymerase chain reaction (PCR) studies for the HHV 8 virus was positive in these samples. PCR studies on pure populations of microdissected mesothelial cells from the HHV 8-related effusions were positive for HHV 8 sequences, whereas those from HIV patients with non-HHV 8 related diseases were negative. Immunohistochemistry for HHV 8 (monoclonal antibody to latent nuclear antigen (LNA-1; ORF-73) on cellblock material demonstrated scattered positive mesothelial cells in three of the five cases of HHV 8-associated effusions. HHV 8 has been recently implicated in the pathogenesis of Kaposi's sarcoma and primary effusion lymphoma. Mesothelial cells in recurrent pleural effusions from patients with Kaposi's sarcoma and Castleman's disease appear to be infected with HHV 8. Additional studies need to be done to define the role of mesothelial cell infection in the pathogenesis of these HHV 8-associated effusions and define the prognostic significance.  相似文献   
35.
36.
The hypothesis was tested that an initial lithium-tricyclic antidepressant (TCA) combination has a better antidepressant effect than standard TCA treatment in non-refractory depression at the beginning of an episode. Twenty bipolar melancholic type depressed inpatients under lithium-TCA treatment were compared with 20 patients with the same diagnosis and TCA-placebo treatment for 5 weeks under double-blind conditions. All patients were male. Initial lithium-TCA treatment reduced depressive symptoms significantly more than antidepressant treatment with TCA and placebo after 5 weeks, but not in weeks 1 or 2. It can be concluded that lithium augmentation of TCA treatment should be started even at the beginning of antidepressant TCA treatment to provide a better treatment response in those patients who will profit from long-term lithium prophylaxis, e.g. bipolar patients with melancholic type depression.  相似文献   
37.
Alterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. (123)I-FP-CIT/(123)I-beta-CIT SPECT and (123)I-IBZM SPECT as well as (18)F-FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. (18)F-FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD.  相似文献   
38.
39.
Many medical conditions are caused or exacerbated by heavy drinking, necessitating alcohol screening and discussion in primary care practices. This is particularly true of hypertension, the most common primary diagnosis in the United States, which has been linked to the regular consumption of 3 or more standard alcoholic beverages a day. The Accelerating Alcohol Screening-Translating Research into Practice (AA-TRIP) project was designed to improve detection and management of alcohol problems in primary care patients with hypertension. Medical providers are being trained using the Practice Partner Research Network's- Translating Research into Practice (PPRNet-TRIP) quality improvement model. This includes a multi-method intervention (electronic medical records, on-site academic detailing, practice feedback reports and annual network meetings) to help practices increase adherence to clinical guidelines. Qualitative analyses of initial steps taken by nine primary care practices toward the routine implementation of alcohol screening guidelines are presented. Organizational factors and provider and patient characteristics all influenced the method and consistency of alcohol screening and intervention. Perceived time constraints, patient sensitivity to questions about alcohol, and possible stigma associated with a diagnosis of alcoholism were also relevant barriers requiring problem solving.  相似文献   
40.
In the mental health service system, disputes take on various forms and exist in both clinical practice and management. Existing policy and administrative practice has favored a combination of medical and judicial/legal models to handle conflicts among consumers, mental health professionals, and others. The authors propose the addition of mediation as a third form of resolving issues, explicate some of the differences between mediation and current methods of resolving conflicts, and suggest benefits of using mediation.Noel Mazade is Executive Director, National Association of State Mental Health Program Directors Research Institute and a practicing mediator. Andrea Blanch is Director of Community Support Programs for the New York Office of Mental Health in Albany, NY.The views presented in this article are those of the authors only. Endorsement by the authors' organizational affiliations is not implied nor should it be inferred.  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