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   5224篇
  免费   306篇
  国内免费   27篇
耳鼻咽喉   71篇
儿科学   155篇
妇产科学   89篇
基础医学   823篇
口腔科学   516篇
临床医学   351篇
内科学   1218篇
皮肤病学   127篇
神经病学   420篇
特种医学   64篇
外科学   508篇
综合类   17篇
一般理论   1篇
预防医学   521篇
眼科学   66篇
药学   367篇
中国医学   25篇
肿瘤学   218篇
  2024年   5篇
  2023年   56篇
  2022年   80篇
  2021年   181篇
  2020年   132篇
  2019年   177篇
  2018年   174篇
  2017年   146篇
  2016年   132篇
  2015年   182篇
  2014年   240篇
  2013年   283篇
  2012年   441篇
  2011年   542篇
  2010年   296篇
  2009年   231篇
  2008年   377篇
  2007年   343篇
  2006年   268篇
  2005年   274篇
  2004年   249篇
  2003年   202篇
  2002年   158篇
  2001年   43篇
  2000年   32篇
  1999年   37篇
  1998年   27篇
  1997年   21篇
  1996年   15篇
  1995年   15篇
  1994年   14篇
  1993年   13篇
  1992年   20篇
  1991年   14篇
  1990年   22篇
  1989年   17篇
  1988年   15篇
  1987年   11篇
  1986年   7篇
  1985年   11篇
  1984年   5篇
  1982年   4篇
  1981年   3篇
  1979年   7篇
  1977年   3篇
  1975年   3篇
  1972年   5篇
  1969年   7篇
  1966年   2篇
  1939年   2篇
排序方式: 共有5557条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Background: Lichen sclerosus (LS) has been identified with increased frequency in families,often associated with HLA markers, mainly DQ7. A genetic co‐etiology seems likely in this setting. Moreover, there is an association of LS with autoimmune disorders, such as the presence of anti‐thyroid peroxidase autoantibodies (anti‐TPO), a hallmark of autoimmune thyroid diseases. Patients and Methods: In 3 families affected by LS, we verified their HLA markers, and identified previously undiagnosed cases of LS and autoimmune disorders. 30 individuals were examined with history, skin biopsy, HLA class I and II typing by PCR‐SSP, and measurement of anti‐TPO, free thyroxine and thyroidstimulating hormones (TSH) levels. Results: There were 8 cases of LS, 50 % of them anti‐TPO+. Autoimmune disorders were found in 40 % (total) and in 87.5 % of those affected. Most common HLA markers were B*15, B*57, CW*03, CW*07, CW*18, DRB1*04, DRB1*07, DRB4*. The three latter have been previously associated with LS. Conclusion: New cases of LS and autoimmune disorders can be detected in first degree relatives of patients with LS. The presence of anti‐TPO antibodies strongly suggests autoimmune thyroiditis. There is intra‐familial association between the haplotype HLA‐B*15 ‐DRB1*04 ‐DRB4* and anti‐TPO,emphasizing their link with thyroiditis. New familial approaches might help to make clear the pathogenesis of LS and its association with autoimmune diseases.  相似文献   
6.
Background Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information regarding cell membrane proliferation, neuronal damage, and energy metabolism. Methods We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions located at the brainstem using Point-resolved spectroscopy sequences. Results Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis was confirmed by biopsy or by clinical follow-up. Conclusions This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role.  相似文献   
7.

Background  

Due to marginalization, trafficking violence, conflicts with the police and organic and social psychological problems associated with the drug, crack is one of the most devastating drugs currently in use. However, there is evidence that some users manage to stay alive and active while using crack cocaine for many years, despite the numerous adversities and risks involved with this behavior. In this context, the aim of the present study was to identify the strategies and tactics developed by crack users to deal with the risks associated with the culture of use by examining the survival strategies employed by long-term users.  相似文献   
8.
PURPOSE: Current treatment for febrile neutropenia (FN) includes hospitalization for evaluation, empiric broad-spectrum antibiotics, and other supportive care. Clinical trials have reported conflicting results when studying whether the colony-stimulating factors (CSFs) improve outcomes in patients with FN. This Cochrane Collaboration review was undertaken to further evaluate the safety and efficacy of the CSFs in patients with FN. METHODS: An exhaustive literature search was undertaken including major electronic databases (CANCERLIT, EMBASE, LILACS, MEDLINE, SCI, and the Cochrane Controlled Trials Register). All randomized controlled trials that compare CSFs plus antibiotics versus antibiotics alone for the treatment of established FN in adults and children were sought. A meta-analysis of the selected studies was performed. RESULTS: More than 8,000 references were screened, with 13 studies meeting eligibility criteria for inclusion. The overall mortality was not influenced significantly by the use of CSF (odds ratio [OR] = 0.68; 95% CI, 0.43 to 1.08; P = .1). A marginally significant result was obtained for the use of CSF in reducing infection-related mortality (OR = 0.51; 95% CI, 0.26 to 1.00; P = .05). Patients treated with CSFs had a shorter length of hospitalization (hazard ratio [HR] = 0.63; 95% CI, 0.49 to 0.82; P = .0006) and a shorter time to neutrophil recovery (HR = 0.32; 95% CI, 0.23 to 0.46; P < .00001). CONCLUSION: The use of the CSFs in patients with established FN caused by cancer chemotherapy reduces the amount of time spent in hospital and the neutrophil recovery period. The possible influence of the CSFs on infection-related mortality requires further investigation.  相似文献   
9.
10.
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