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   1435篇
  免费   97篇
  国内免费   8篇
耳鼻咽喉   1篇
儿科学   41篇
妇产科学   44篇
基础医学   241篇
口腔科学   6篇
临床医学   102篇
内科学   346篇
皮肤病学   73篇
神经病学   197篇
特种医学   57篇
外科学   151篇
综合类   9篇
预防医学   52篇
眼科学   12篇
药学   141篇
中国医学   6篇
肿瘤学   61篇
  2021年   32篇
  2020年   18篇
  2019年   30篇
  2018年   34篇
  2017年   15篇
  2016年   29篇
  2015年   25篇
  2014年   36篇
  2013年   61篇
  2012年   77篇
  2011年   66篇
  2010年   55篇
  2009年   51篇
  2008年   70篇
  2007年   67篇
  2006年   62篇
  2005年   67篇
  2004年   74篇
  2003年   65篇
  2002年   70篇
  2001年   34篇
  2000年   50篇
  1999年   48篇
  1998年   14篇
  1997年   13篇
  1996年   20篇
  1995年   11篇
  1994年   9篇
  1992年   23篇
  1991年   25篇
  1990年   24篇
  1989年   13篇
  1988年   14篇
  1987年   9篇
  1986年   22篇
  1985年   17篇
  1984年   30篇
  1983年   11篇
  1982年   7篇
  1980年   9篇
  1979年   21篇
  1978年   13篇
  1977年   6篇
  1975年   10篇
  1974年   7篇
  1973年   7篇
  1972年   8篇
  1971年   6篇
  1970年   6篇
  1969年   7篇
排序方式: 共有1540条查询结果,搜索用时 336 毫秒
1.
Although histopathology is the time‐honored gold standard diagnostic measure in dermatology, several factors may detract from an accurate microscopic diagnosis. Limiting factors include: human error, suboptimal biopsy‐site selection or biopsy technique, and inherent restrictions of vertical tissue sectioning that lead to incomplete microscopic evaluation of the lesion. Reflectance confocal microscopy (RCM) is a non‐invasive imaging tool that allows for the cellular‐level examination of the lesion, at a horizontal plane, which may complement the subsequent vertical histopathological tissue examination. Herein, we report a case series whereby prebiopsy RCM examination enhanced the accuracy of histopathological diagnosis or allowed for a critical appraisal of initial histopathological misdiagnosis.  相似文献   
2.
Aiolfi  A.  Cavalli  M.  Sozzi  A.  Lombardo  F.  Mendogni  P.  Nosotti  M.  Bonitta  G.  Bruni  P. G.  Campanelli  G.  Bona  D. 《Hernia》2022,26(6):1679-1685
Hernia - Paraesophageal hiatal hernia (PEH) is characterized by protrusion of intra-abdominal organs into the posterior mediastinum. Respiratory symptoms and reduced pulmonary function have been...  相似文献   
3.
ABSTRACT

Introduction: Steroid hormones are responsible for specific changes in the endometrium during the menstrual cycle, when they are sequentially secreted and, because of this, in the early days sequential combined oral contraceptive regimens were utilized. The same basic concept has been utilized with multi-phasic regimens, in order to produce endometrial pictures mimicking the normal cycle.

Areas covered: The Endometrial effects of progestins and estrogens; combined monophasic high- (50 μg), medium- (30 μg), low- (20 μg), ultralow- (15 μg) estrogen content; sequential regimens; multiphasic combinations; treatment schedules.

Cervical effects of combined high-dose and sequential combinations, including evidence for an increase in malignant lesions.

Expert opinion: Overall, combined oral contraceptives (COCs) inhibit normal proliferative changes and the endometrium becomes thin, narrow, with widely spaced glands and pre-decidual changes in the stroma. During the first few cycles the progestin induces a coexistence of proliferative and secretory features; with time, the picture changes because the progestin induces a down-regulation of estrogen receptors, resulting in tortuous glands similar to those in the secretory phase, but characterized by a quiescent, atrophic glandular epithelium.

In the cervical epithelium, under the influence of high-dose COCs, endocervical glands became hypersecretory and in some instances, distinctive type of atypical polypoid endocervical hyperplasia is found.  相似文献   
4.
5.
6.
7.
The objective of this observational cohort study was to analyse the age‐related changes of periodic leg movements during sleep using the newest international scoring rules, to expand past analyses, including patients in the paediatric age range, and also to analyse the changes of short‐interval and isolated leg movements during sleep throughout the lifespan. One hundred and sixty‐five patients (84 women) with restless legs syndrome were recruited in the following age groups: 16 preschoolers (≤5 years of age), 29 school‐age children (6–12 years), 19 adolescents (13–17 years), 17 young adults (19–40 years), 47 adults (41–60 years) and 37 seniors (>60 years). Total, periodic, short‐interval and isolated leg movements during sleep and periodicity indexes were obtained by polysomnography. The total index showed (quartic polynomial interpolation) a decrease before 10 years, followed by a steady increase up to 30 years, a relatively stable period until 60 years, and a final increase up to 80 years. This course was almost entirely due to changes in periodic movements. Isolated movements did not change significantly and short‐interval movements showed only an increase in seniors. Our study indicates that, in restless legs syndrome, the total index shows a peculiar and unique course throughout the lifespan, mainly due to periodic movements. These age‐related changes may mirror developmental changes in network complexity known to occur in dopaminergic circuits. These data further confirm the need to better assess the periodicity of leg movements in sleep during the human development period, in order to obtain clinically useful information.  相似文献   
8.
9.
Phenotypic changes induced by extracellular vesicles have been implicated in mesenchymal stromal cell–promoted recovery of AKI. MicroRNAs are potential candidates for cell reprogramming toward a proregenerative phenotype. The aim of this study was to evaluate whether microRNA deregulation inhibits the regenerative potential of mesenchymal stromal cells and derived extracellular vesicles in a model of glycerol-induced AKI in severe combined immunodeficient mice. We generated mesenchymal stromal cells depleted of Drosha to alter microRNA expression. Drosha-knockdown cells produced extracellular vesicles that did not differ from those of wild-type cells in quantity, surface molecule expression, and internalization within renal tubular epithelial cells. However, these vesicles showed global downregulation of microRNAs. Whereas wild-type mesenchymal stromal cells and derived vesicles administered intravenously induced morphologic and functional recovery in AKI, the Drosha-knockdown counterparts were ineffective. RNA sequencing analysis showed that kidney genes deregulated after injury were restored by treatment with mesenchymal stromal cells and derived vesicles but not with Drosha-knockdown cells and vesicles. Gene ontology analysis showed in AKI an association of downregulated genes with fatty acid metabolism and upregulated genes with inflammation, matrix-receptor interaction, and cell adhesion molecules. These alterations reverted after treatment with wild-type mesenchymal stromal cells and extracellular vesicles but not after treatment with the Drosha-knockdown counterparts. In conclusion, microRNA depletion in mesenchymal stromal cells and extracellular vesicles significantly reduced their intrinsic regenerative potential in AKI, suggesting a critical role of microRNAs in recovery after AKI.  相似文献   
10.
Cerebrospinal fistula might occur in different ways. CSF closure techniques have undergone significant evolution that has led to the consolidation of the transnasal endoscopic approach. Despite the existence of multiple publications, meaningful information is still lacking in clinical practice and the literature about the ideal method, material, and timing for repair of CSF. The purpose of this review was to summarize the success rate of endoscopic CSF leak repair as well as whether specific techniques or materials influence the primary success rate through a review of the latest advancements in endoscopic CSF management published in the past 10 years. The principles of multilayer reconstructions and the routine use of vascularized flaps in expanded endonasal surgery have reduced postoperative CSF leaks' failure rates between 5% and 10% (4% in this meta‐analysis). Effective endoscopic anterior skull base (ASB) closure may be achieved by multiple reconstructive techniques, which should be tailored case by case according to the patient and defect conditions.  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