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   383108篇
  免费   15280篇
  国内免费   901篇
耳鼻咽喉   3300篇
儿科学   12030篇
妇产科学   7248篇
基础医学   46450篇
口腔科学   6599篇
临床医学   32179篇
内科学   74708篇
皮肤病学   4431篇
神经病学   36276篇
特种医学   17212篇
外国民族医学   51篇
外科学   58662篇
综合类   4714篇
现状与发展   2篇
一般理论   216篇
预防医学   33222篇
眼科学   6997篇
药学   24124篇
  2篇
中国医学   1029篇
肿瘤学   29837篇
  2023年   996篇
  2022年   1686篇
  2021年   3791篇
  2020年   2562篇
  2019年   3691篇
  2018年   25813篇
  2017年   20274篇
  2016年   22798篇
  2015年   5377篇
  2014年   7020篇
  2013年   9683篇
  2012年   19971篇
  2011年   34244篇
  2010年   26544篇
  2009年   18865篇
  2008年   31494篇
  2007年   34461篇
  2006年   13537篇
  2005年   15237篇
  2004年   15910篇
  2003年   16050篇
  2002年   13738篇
  2001年   3883篇
  2000年   3714篇
  1999年   3696篇
  1998年   3138篇
  1997年   2533篇
  1996年   2116篇
  1995年   2024篇
  1994年   1768篇
  1993年   1747篇
  1992年   2264篇
  1991年   2251篇
  1990年   2065篇
  1989年   1986篇
  1988年   1717篇
  1987年   1708篇
  1986年   1580篇
  1985年   1524篇
  1984年   1347篇
  1983年   1232篇
  1982年   1230篇
  1981年   1145篇
  1980年   1018篇
  1979年   996篇
  1978年   772篇
  1977年   764篇
  1976年   645篇
  1975年   680篇
  1974年   682篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
151.
This report looks at outpatient treatment of nasopharyngeal inlet stenosis, a more commonly seen postoperative complication of uvulopalatopharyngoplasty (UPPP). It does not study the effectiveness of the UPPP for treatment of obstructive sleep apnea syndrome (OSAS). The authors evaluated six patients who had a UPPP for OSAS, all of whom developed stenosis in the nasopharyngeal inlet ranging from 14 mm to complete closure. Two patients had failed rotation flap repairs. The carbon dioxide laser was used to treat these patients in the office under a local anesthesia in a staged manner. We now have patients from 3 months to 12 months follow-up who have had stenosis treated successfully. We believe that the postoperative complication of nasopharyngeal inlet stenosis after UPPP can be treated in a safe and cost-effective manner in the office setting.  相似文献   
152.
The present study investigated the expression of c-erbB-2 in 59 meningiomas, including different histological subtypes and anaplastic variants, by immunocytochemistry and molecular biological techniques. Immunohistochemistry using the monoclonal antibody FWP-51 directed against c-erbB-2-encoded oncoprotein gp185 demonstrated variable degrees of immunoreactivity in all meningiomas. The intensity of immunostaining correlated with the degree of expression as assessed by Western analysis in 28 meningiomas using polyclonal antiserum 21N. There was no correlation between the degree of expression and histological variants. Immunoreactivity of all menigiomas was distinctly less intense, however, than that of the human breast cancer cell line SK-BR-3, and slightly lower than that of brain metastases of breast and ovarian carcinomas that served as positive controls for both methods. By Southern analysis all meningiomas showed a single copy of the c-erbB-2 gene. Non-neoplastic arachnoid cap cells also exhibited c-erbB-2 expression and the degree of immunoreactivity was comparable with the majority of meningiomas. These data argue against an overexpression of c-erbB-2 in meningiomas, but rather indicate a cell-type-specific constitutive expression of the c-erbB-2 gene product in meningiomas and their putative progenitor cells. Since a subgroup of meningiomas is known to express progesterone receptors (PR), gp185 immunoreactivity was compared to the hormone receptor status using monoclonal antibody KD68. Fifty-six percent meningiomas showed PR immunoreactivity, but there was no statistically significant correlation with the degree of gp185 expression.This study was supported by a grant of the Tumorzentrum Heidelberg/Mannheim (M.K., No. 10028060)  相似文献   
153.
Irritability is often a problem for patients with Post-Traumatic Stress Disorder (PTSD). We describe two cases that illustrate the use of lithium in the treatment of veterans with PTSD who complained of serious problems with irritability or angry outbursts. These cases are discussed in the context of evidence that lithium may be useful in other patients with disorders of impulse control. The evidence linking disorders of anger and impulse control to a dysregulation in neurotransmitter regulation, particularly in serotonergic pathways, supports a psychopharmacologic approach to treatment. These findings should lead to further study of the role of lithium in the treatment of this symptom complex in patients with PTSD.  相似文献   
154.
155.
156.
157.
Bilateral ulnar agenesis is a rare abnormality. A total of 36 cases are analyzed: 35 of these are documented in the literature and 1 stillborn male is presented in this study. Most patients had one of the three conditions: Al-Awadi/Raas-Rothschild syndrome, syndrome of ulnar aplasia with split hand/split foot deformity, or the Brachmann—de Lange syndrome. Fifty percent of all cases with bilateral ulnar agenesis were associated with lower limb defects and these cases, for the most part, also belonged to the aforementioned syndromes. Nonskeletal, internal organ malformations were identified in 34% of all patients. Nine patients presented with isolated bilateral ulnar agenesis. The Al-Awadi/Raas-Rothschild syndrome and the split hand/split foot deformity are heritable disorders. There was no evidence for genetic etiology in most of the other cases. Bilateral ulnar agenesis in our fetus was part of the Brachmann—de Lange syndrome with associated cardiac defect, diaphragmatic hernia, and umbilical artery agenesis.  相似文献   
158.
159.
160.
The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.  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