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   1078篇
  免费   132篇
  国内免费   1篇
耳鼻咽喉   26篇
儿科学   21篇
妇产科学   10篇
基础医学   143篇
口腔科学   67篇
临床医学   92篇
内科学   207篇
皮肤病学   45篇
神经病学   162篇
特种医学   16篇
外科学   138篇
综合类   29篇
一般理论   3篇
预防医学   84篇
眼科学   17篇
药学   53篇
中国医学   1篇
肿瘤学   97篇
  2023年   21篇
  2022年   35篇
  2021年   80篇
  2020年   38篇
  2019年   59篇
  2018年   39篇
  2017年   19篇
  2016年   17篇
  2015年   27篇
  2014年   34篇
  2013年   47篇
  2012年   47篇
  2011年   61篇
  2010年   30篇
  2009年   20篇
  2008年   30篇
  2007年   47篇
  2006年   41篇
  2005年   34篇
  2004年   42篇
  2003年   33篇
  2002年   31篇
  2001年   22篇
  2000年   27篇
  1999年   17篇
  1998年   9篇
  1997年   12篇
  1996年   5篇
  1995年   11篇
  1994年   17篇
  1993年   6篇
  1992年   18篇
  1991年   14篇
  1990年   24篇
  1989年   22篇
  1988年   22篇
  1987年   16篇
  1986年   17篇
  1985年   12篇
  1984年   13篇
  1983年   13篇
  1980年   4篇
  1979年   6篇
  1974年   6篇
  1973年   6篇
  1972年   5篇
  1970年   6篇
  1968年   5篇
  1964年   4篇
  1961年   4篇
排序方式: 共有1211条查询结果,搜索用时 0 毫秒
21.

Background

Leiomyosarcoma is rare in the oral cavity, where it may arise as primary, radiation-associated, or metastatic tumor. This article reports two cases of oral leiomyosarcoma, discussing the range of clinicopathological features and the significance of these presentations.

Case report

One case is a radiation-associated leiomyosarcoma arising in the tongue of a 71-year-old male occurring 22?years after radiation therapy for tonsil squamous cell carcinoma that was surgically treated. The other one is a mandible metastasis from a retroperitoneal widespread leiomyosarcoma in a 69-year-old man, who was treated by surgery and chemotherapy but died from the disease.

Discussion

Post-radiotherapy sarcomas of the oral cavity and oral metastasis from soft tissue sarcomas are very uncommon, but based on patient??s clinical history, they should be considered by oral health care providers in order to allow an early diagnosis and proper and timely management. Finally, to the best of our knowledge, this seems to be the first reported case of tongue leiomyosarcoma arising in a previously irradiated field.  相似文献   
22.
23.
The effects of early androgen treatment on neurodevelopmental performance in pre‐pubertal boys with 47,XXY have not been well investigated. The influence of hormones on brain development in humans suggests that a positive effect on neurodevelopmental outcome in young boys with XXY may be plausible with hormone replacement therapy. The aim of the study was to investigate retrospectively if an early course of androgen treatment (three injections of testosterone enanthate, 25 mg, each) had an impact on specific domains of neurodevelopmental function in boys with 47,XXY at 36 and 72 months of age. One hundred one boys with a karyotype of 47,XXY had neurodevelopmental assessments. The retrospective chart review resulted in one group (n = 34) who had received androgen treatment during infancy and the second group was untreated (N = 67). Statistical analysis was completed to determine if there was a positive effect from treatment observed at 36 and at 72 months on multiple domains of development. There were significant differences in multiple cognitive domains in the group who received androgen treatment, including multiple measures of language, intellectual, and neuromotor skills. Improved function was observed in neurodevelopmental outcome in boys with 47,XXY at 36 and 72 months who had been treated with a short course of androgen treatment in infancy. Continued research is underway to expand our understanding of the relationship of androgen, brain function, and neurobehavioral and neurodevelopmental outcome in boys with 47,XXY. © 2013 Wiley Periodicals, Inc.  相似文献   
24.
25.
Hereditary hemorrhagic telangiectasia (HHT) is an inherited mucocutaneous disease characterized by recurrent epistaxis, lesions on skin and oral mucosa, and arteriovenous malformations of the soft tissues. This article describes the treatment of a 64-year-old woman with a bleeding nodule, which was diagnosed as an arteriovenous malformation of the gingival mucosa. She was treated using sclerotherapy. Patients with HHT can be treated in the dental office and vascular malformations of these patients can be successfully managed with sclerotherapy, which eliminates the need for invasive surgical procedures and the possibility of postsurgical complications.  相似文献   
26.
27.
Human defensins play a fundamental role in the initiation of innate immune responses to some microbial pathogens. Here we show that human defensin alpha-1 displays a trypanocidal role against Trypanosoma cruzi, the causative agent of Chagas' disease. The toxicity of human defensin alpha-1 against T. cruzi is mediated by membrane pore formation and the induction of nuclear and mitochondrial DNA fragmentation, leading to trypanosome destruction. Exposure of trypomastigote and amastigote forms of T. cruzi to defensin alpha-1 significantly reduced parasite viability in a peptide concentration-dependent and saturable manner. The toxicity of defensin alpha-1 against T. cruzi is blocked by anti-defensin alpha-1 immunoglobulin G. Electron microscopic analysis of trypomastigotes exposed to defensin alpha-1 revealed pore formation in the cellular and flagellar membranes, membrane disorganization, and blebbing as well as cytoplasmic vacuolization. Furthermore, human defensin alpha-1 enters the trypanosome when membrane pores are present and is associated with later intracellular damage. Trypanosome membrane depolarization abolished the toxicity of defensin alpha-1 against the parasite. Preincubation of trypomastigotes with defensin alpha-1 followed by exposure to human epithelial cells significantly reduced T. cruzi infection in these cells. Thus, human defensin alpha-1 is an innate immune molecule that causes severe toxicity to T. cruzi and plays an important role in reducing cellular infection. This is the first report showing that human defensin alpha-1 causes membrane pore formation in a human parasite, leading to trypanosome destruction.  相似文献   
28.
Plasma cell neoplasia is a lymphoid neoplastic proliferation of B cells. This denomination encloses multiple myeloma (MM), solitary bone plasmacytoma and extramedullary plasmacytoma. MM consists of a clonal proliferation of plasma cells based in the bone marrow, with various degrees of differentiation. Neoplastic cells usually produce great amounts of monoclonal light or heavy chains of immunoglobulin that can be detected in serum or urine. The disease is more frequently in men and the average age at diagnosis is about 60 years. The diagnosis is established by blood and urine exams and medullary biopsy. Patients may present renal failure, bone pain, fatigue, recurrent infections and nervous system dysfunction. Oral manifestations may be the first sign of MM, highlighting the importance of the dentist in the early diagnosis of the disease. Treatment involves mainly irradiation and chemotherapy and the prognosis is generally poor. This paper reports a case of a 65 years old black female who had a complaint of a painful mass in the maxilla that prompted a MM diagnosis.  相似文献   
29.

Background

The chromophobe subtype represents the third most common histological subtype of renal cell carcinoma (chRCC). Due to the rarity of this subtype only one publication regarding the specific analysis of clinical and histopathological criteria as well as survival analysis of more than 200 patients with chRCC is known to date.

Materials and methods

A total of 6,234 RCC patients from 11 centres who were treated by (partial) nephrectomy are contained in the database of this multinational study. Of the patients 259 were diagnosed with chRCC (4.2?%) and thus formed the study group for this retrospective investigation. These subjects were compared to 4,994 patients with a clear cell subtype (80.1?%) with respect to clinical and histopathological criteria. The independent influence of the chromophobe subtype regarding tumor-specific survival and overall survival was determined using analysis by Cox proportional hazards regression models. The median follow-up was 59 months (interquartile range 29-106 months).

Results

The chRCC patients were significantly younger (60 vs. 63.2 years, p?<?0.001), more often female (50 vs. 41?%, p?=?0.005) and showed simultaneous distant metastases to a lesser extent (3.5 vs. 7.1?%, p?=?0.023) compared to patients with a clear cell subtype. Despite a comparable median tumor size a ≥?pT3 tumor stage was diagnosed in only 24.7?% of the patients compared to of 30.5?% in patients with a clear cell subtype (p?=?0.047). In addition to the clinical criteria of age, sex and distant metastases, the histological variables pTN stage, grade and tumor size showed a significant influence on tumor-specific and overall survival. However, in the multivariable Cox regression analysis no independent effect on tumor-specific mortality (HR 0.88, p?=?0.515) and overall mortality (HR 1.00, p?=?0.998) due to the histological subtype was found (c-index 0.86 and 0.77, respectively).

Conclusions

Patients with chRCC and clear cell RCC differ significantly concerning the distribution of clinical and histopathological criteria. Patients with chRCC present with less advanced tumors which leads to better tumor-specific survival rates in general; however, this advantage could not be verified after adjustment for the established risk factors.  相似文献   
30.
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