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   238822篇
  免费   15125篇
  国内免费   994篇
耳鼻咽喉   2567篇
儿科学   6114篇
妇产科学   4543篇
基础医学   29833篇
口腔科学   4431篇
临床医学   24383篇
内科学   50138篇
皮肤病学   3457篇
神经病学   24085篇
特种医学   10275篇
外国民族医学   16篇
外科学   37530篇
综合类   2560篇
现状与发展   1篇
一般理论   179篇
预防医学   16777篇
眼科学   5627篇
药学   15710篇
  1篇
中国医学   320篇
肿瘤学   16394篇
  2023年   1347篇
  2022年   2217篇
  2021年   5381篇
  2020年   3075篇
  2019年   5082篇
  2018年   6097篇
  2017年   4501篇
  2016年   4907篇
  2015年   5815篇
  2014年   8420篇
  2013年   11337篇
  2012年   17418篇
  2011年   18169篇
  2010年   10143篇
  2009年   9397篇
  2008年   15974篇
  2007年   16790篇
  2006年   16316篇
  2005年   16193篇
  2004年   15212篇
  2003年   13903篇
  2002年   13316篇
  2001年   2067篇
  2000年   1549篇
  1999年   2107篇
  1998年   2827篇
  1997年   2257篇
  1996年   1957篇
  1995年   1803篇
  1994年   1561篇
  1993年   1514篇
  1992年   1035篇
  1991年   992篇
  1990年   857篇
  1989年   811篇
  1988年   746篇
  1987年   689篇
  1986年   711篇
  1985年   742篇
  1984年   961篇
  1983年   826篇
  1982年   1056篇
  1981年   984篇
  1980年   857篇
  1979年   505篇
  1978年   533篇
  1977年   475篇
  1976年   437篇
  1975年   345篇
  1974年   337篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Fractures of the calcaneus generally occur in the event of high-energy trauma, resulting in complex, three-dimensionally oriented fracture patterns. Surgical management is generally indicated for displaced intra-articular fractures, which allows restoration of calcaneal height, width and overall morphology, in addition to the posterior facet articular surface where possible, and allows for a late in situ arthrodesis as a means of salvage in the event of posttraumatic arthritis. What follows is a brief discussion of our preferred methods in the diagnosis and management of calcaneal fractures.  相似文献   
102.
103.
104.
The objective of this study was to investigate the effect of fluoridated elastomeric ligatures on the microbiology of local dental plaque in vivo. This randomized, prospective, longitudinal, clinical trial had a split-mouth crossover design. The subjects were 30 patients at the beginning of their treatment with fixed orthodontic appliances in the orthodontic departments of the Liverpool and the Sheffield dental hospitals in the United Kingdom. The study consisted of 2 experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly allocated at the first visit to be placed around brackets on tooth numbers 12, 11, 33 or 22, 21, 43. Nonfluoridated elastomers were placed on the contralateral teeth. Standard nonantibacterial fluoridated toothpaste and mouthwash were supplied. After 6 weeks (visit 2), the elastomers were removed, placed in transport media, and plated on agar within 2 hours. Nonfluoridated elastomers were placed on all brackets for 1 visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the teeth contralateral to those that received them at visit 1. At visit 4, the procedures at visit 2 were repeated. Samples were collected on visits 2 and 4. A logistic regression was performed, with the presence or absence of streptococcal or anaerobic growth as the dependent variable. A mixed-effects analysis of variance was carried out with the percentage of streptococcal or anaerobic bacterial count as the dependent variable. The only significant independent variables were the subject variable (P =<.001) for the percentage of streptococcal and anaerobic bacterial count and the visit variable for the percentage of streptococcal count (P =<.001). The use of fluoridated or nonfluoridated elastomers was not significant for percentage of either streptococcal (P =.288) or anaerobic count (P =.230). Fluoridated elastomers are not effective at reducing local streptococcal or anaerobic bacterial growth after a clinically relevant time in the mouth.  相似文献   
105.
Thrombotic microangiopathy is a rare but important finding in the context of organ transplantation. Acute renal insufficiency in the setting of hemolysis and thrombocytopenia, a triad that constitutes 'hemolytic uremic syndrome', can be associated with, or triggered by, conditions such as verocytotoxin-producing Escherichia coli, viral infections, malignant hypertension, scleroderma, allograft rejection, lupus erythematosus, pregnancy, and medications including mitomycin C, calcineurin inhibitors, and oral contraceptives. After renal transplantation, it can occur, as either a de novo episode, or recurrent disease. Calcineurin inhibitors have long been associated with post-transplantation thrombotic microangiopathy. Sirolimus has been used as a primary immunosuppressant in patients transplanted with a history of earlier hemolytic-uremic syndrome, and also as rescue therapy in patients with calcineurin-inhibitor-associated thrombotic microangiopathy. We describe four cases where there was significant thrombotic microangiopathy in the context of contemporaneous or contiguous calcineurin inhibitor and sirolimus usage. As the intrarenal cyclosporin concentration is thought to be significantly elevated when cyclosporin and sirolimus are used together, this may explain these findings, and mandates caution in their co-administration.  相似文献   
106.
This research was conducted at a summer camp for siblings of children with cancer. The camp is designed to address emotional problems, provide peer interaction and validation, and bolster siblings' self-esteem. Standardized measures assessing posttraumatic stress, anxiety, quality of life, and self-esteem were administered to 77 siblings (ages 6-17) prior to attending camp and again 3 months after camp. From pre- to post-camp, the siblings reported statistically significant decreases in symptoms of posttraumatic stress and anxiety, and statistically significant improvements in quality of life and self-esteem. These preliminary findings are encouraging and suggest the value of camp as a psychological intervention and provide a model for other pediatric cancer facilities designing intervention programs for siblings.  相似文献   
107.
RATIONALE AND OBJECTIVES: To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. MATERIALS AND METHODS: We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. RESULTS: Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. CONCLUSION: There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation.  相似文献   
108.
109.
The value of a long-term treatment with clonazepam in the prophylaxis of affective disorder is discussed controversially in the scientific literature. Altogether there are only a few reports on the use of this compound as a mood stabilizer, most of them describing patients suffering from bipolar affective disorder. The aim of this investigation was to evaluate clonazepam as a phase prophylactic medication in affective disorder. We conducted a retrospective chart review in 34 out-patients of our lithium clinic (15 suffering from unipolar depression, 15 from bipolar disorder, four from schizoaffective disorder), who had been treated with clonazepam as a long-term medication. Clonazepam was either given as monotherapy, or as in the case of lithium non-responders, as adjunctive therapy. Patients with unipolar depression had significantly (P=0.026) less depressive episodes after initiation of treatment with clonazepam. Patients with bipolar disorder did not benefit from this therapy. Neither manic/hypomanic phases nor depressive episodes were reduced in this group of patients. Interestingly, clonazepam also reduced affective phases in our four schizoaffective patients on a trend level. Our results indicate that patients with unipolar depression may benefit from a maintenance treatment with clonazepam. Due to methodological limitations our results need to be replicated in controlled double-blind randomized clinical trials.  相似文献   
110.
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