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   624篇
  免费   33篇
  国内免费   5篇
耳鼻咽喉   3篇
儿科学   33篇
妇产科学   7篇
基础医学   70篇
口腔科学   18篇
临床医学   83篇
内科学   117篇
皮肤病学   69篇
神经病学   13篇
特种医学   126篇
外科学   25篇
综合类   22篇
预防医学   23篇
眼科学   4篇
药学   15篇
  1篇
肿瘤学   33篇
  2023年   2篇
  2022年   3篇
  2021年   2篇
  2020年   5篇
  2019年   6篇
  2018年   13篇
  2017年   4篇
  2016年   9篇
  2015年   14篇
  2014年   16篇
  2013年   21篇
  2012年   11篇
  2011年   17篇
  2010年   29篇
  2009年   29篇
  2008年   15篇
  2007年   23篇
  2006年   17篇
  2005年   15篇
  2004年   10篇
  2003年   5篇
  2002年   8篇
  2001年   6篇
  2000年   4篇
  1999年   6篇
  1998年   37篇
  1997年   46篇
  1996年   40篇
  1995年   21篇
  1994年   30篇
  1993年   22篇
  1992年   10篇
  1991年   10篇
  1990年   13篇
  1989年   25篇
  1988年   21篇
  1987年   10篇
  1986年   8篇
  1985年   8篇
  1984年   14篇
  1983年   14篇
  1982年   12篇
  1981年   11篇
  1980年   7篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1973年   1篇
  1971年   1篇
  1969年   1篇
排序方式: 共有662条查询结果,搜索用时 15 毫秒
571.
572.
573.
Background: Scleroderma/morphea is characterized by expansion of the dermis with thickened collagen bundles and loss of CD34+ dermal dendrocytes. Variable elastic fiber changes have been described, but to our knowledge, no systematic study of the elastic fiber pattern correlated with CD34 expression has been reported.
Methods: To better define the typical elastic fiber morphology, we examined seven cases of normal skin and 28 cases of scleroderma/morphea ranging from inflammatory to sclerosing stages. All but four biopsies were submitted with a clinical impression of either scleroderma or morphea. CD34 immunohistochemistry was performed on 26 biopsies with available tissue.
Results: Elastic van Gieson stain showed preservation of elastic fibers in all cases. In addition, straightening with parallel orientation and compression between thickened collagen bundles was frequently present and was graded as limited in 46% and diffuse in 54% of cases. The extent of elastic fiber alteration correlated with the degree of sclerosis. A variable loss of CD34+ dermal dendritic cells was seen in all cases.
Conclusion: This study confirms the preservation and frequent presence of parallel, straightened and compressed elastic fibers in scleroderma/morphea and suggests that the elastic fiber pattern, in addition to CD34 immunohistochemistry, may serve as a useful diagnostic adjunct.  相似文献   
574.
575.

Background:

Displaced intracapsular femoral neck fractures continue to be a difficult problem to treat. Various treatment modalities and their modifications have been proposed to improve the outcome. Osteosynthesis and primary valgus angulation osteotomy is one of them. Technique and outcome in a consecutive series of recent intracapsular femoral neck fractures in young adults, from a single center, is presented.

Materials and Methods:

Fifty-five patients of recent (<3 weeks old) displaced intracapsular fracture neck femur (Garden III and IV, Pauwels III, with or without comminution) in the age group 20-50 years (mean 35.4±10.4 years) were subjected to osteosynthesis and primary valgus intertrochanteric osteotomy using contoured broad dynamic compression plate (DCP). The patients were followed up from two to six years (mean 4.6 years).

Results:

Fifty-one fractures united by six months of the index procedure (92.7% union range). Avascular necrosis (AVN) developed in six patients (11%). The other complications were shortening (six), coxa vara (two), infection (two) and delayed union at osteotomy site (one). Excellent results were achieved in 48, good/fair in four and poor in three patients.

Conclusion:

Osteosynthesis with cancellous screw and primary valgus intertrochanteric osteotomy stabilized by a contoured broad DCP is a simple, easy to perform, biological treatment. Failure in a particular case can be treated with any appropriate second procedure.

Level of Evidence:

IV  相似文献   
576.
Follicular mucinosis is currently recognized as a histopathological finding characterized by the accumulation of mucin within follicular epithelium and is commonly associated with follicular mycosis fungoides (MF). We report the finding of follicular mucinosis in a cutaneous nodule of human T-lymphotropic virus type 1 (HTLV-1) associated adult T-cell leukemia/lymphoma (ATLL). The patient was a 69-year-old female of Caribbean descent with a history of ATLL who presented with erythematous nodules on the chest and abdomen. Histopathologic examination showed a pan-dermal infiltrate of medium-to-large sized atypical lymphocytes extending into follicular epithelium where they associated with large mucin deposits. Immunohistochemical stains showed that the atypical lymphocytes were positive for CD3, CD4 and CD25 and negative for CD30. Cutaneous lesions of ATLL, which often present histopathologically as an epidermotropic lymphoma with Pautrier-type collections, are often difficult to distinguish from MF. Until recently, lymphoma-associated follicular mucinosis seemed specific to MF and Sézary syndrome (SS), being reported only once in a lesion of ATLL. We report a second case of ATLL-associated follicular mucinosis to increase awareness of this possible association, and briefly review the literature of follicular mucinosis-associated hematologic malignancies, ultimately cautioning against the interpretation of all cutaneous lymphoma-related follicular mucinosis as MF/SS.  相似文献   
577.
Primary cutaneous neuroendocrine carcinoma, also known as Merkel cell carcinoma (MCC), usually presents as a dermal and/or subcutaneous tumor. Rarely, it is confined to the epidermis or adnexal epithelium [MCC in situ (MCCIS)]. Little is known about the spectrum of features and biology of MCCIS. Herein, we report a case of MCCIS arising on the cheek of a 77-year-old Caucasian male, which was associated with squamous cell carcinoma in situ. The tumor cells of both the neuroendocrine and squamous components prominently involved adnexal structures but did not invade the dermis. The tumor cells with neuroendocrine features were immunoreactive for cytokeratin-20, chromogranin and synaptophysin. They also expressed p53 but were non-reactive with the monoclonal antibody CM2B4. Lack of labeling for CM2B4 is in keeping with prior observations of combined squamous and MCC. Our findings support the concept of a distinct subtype of virus-independent cutaneous neuroendocrine carcinoma that differs from conventional MCC. The observed overexpression of p53 suggests that the development of this tumor type may be related to chronic ultraviolet damage.  相似文献   
578.

BACKGROUND:

The current study was conducted to determine whether the use of cochlear‐sparing intensity‐modulated radiotherapy (IMRT) boost results in excess local failures in children with medulloblastoma.

METHODS:

Fifty children with a median age of 7.8 years underwent resection, craniospinal irradiation (CSI), IMRT posterior fossa (PF) and/or tumor bed (TB) boost, and cisplatin‐based chemotherapy for medulloblastoma. For standard‐risk patients, the CSI dose was 18 to 23.4 grays (Gy) and was followed either by an IMRT PF boost to 36 Gy and a TB boost of 54 to 55.8 Gy (n = 29) or by an IMRT TB boost to 55.8 Gy (n = 4). For high‐risk patients, the CSI dose was 36 to 39.6 Gy followed by an IMRT PF boost to 54 to 55.8 Gy (n = 8), an IMRT PF boost to 45 Gy and a TB boost to 55.8 Gy (n = 2), or an IMRT TB boost to 55.8 Gy (n = 7). For the TB boost, a 2‐cm margin around the surgical bed was treated in most patients.

RESULTS:

The 5‐year overall and progression‐free survival rates (±standard deviation) were 72% ± 6.6% and 68.3% ± 6.8%, respectively, for all patients; 77.8% ± 7.4% and 75.1% ± 7.6%, respectively, for standard‐risk patients; and 60.8% ± 12.8% and 55.4% ± 12.8%, respectively, for high‐risk patients. The 5‐year PF control rate was 90.5% ± 4.6%. TB failures occurred in 3 patients (including 2 patients who had distant failure), whereas an isolated non‐TB PF failure occurred in 1 patient.

CONCLUSIONS:

The use of IMRT was associated with excellent local control and did not result in excess PF failures outside of the TB. Cancer 2011. © 2010 American Cancer Society.  相似文献   
579.
580.
Fifteen plant species were collected from the Nelspruit Botanical Garden based on a list of plants provided by Phytomedicine Programme at the University of Pretoria and their ethnopharmacological information. Hexane, dichloromethane (DCM), acetone and methanolic extracts were screened for antimycobacterial activity against Mycobacterium smegmatis. The acetone extract of Milletia stulhimannii was the most active, showing activity against Mycobacterium smegmatis with minimum inhibitory concentration (MIC) value of 0.13 mg/ml. Acetone extracts for all plants had lower MIC values ranging between 0.11–1.25 mg/ml against M. smegmatis. Milletia stulhimannii, Albizia gummifera, Xanthocercis zambesiaca and Barringtonia racemosa have shown great potential as anti-tuberculosis agents. They were active against M. smegmatis with average MIC values of acetone extracts of 0.13 mg/ml.  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