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   5806篇
  免费   564篇
  国内免费   134篇
耳鼻咽喉   73篇
儿科学   107篇
妇产科学   150篇
基础医学   578篇
口腔科学   98篇
临床医学   650篇
内科学   974篇
皮肤病学   72篇
神经病学   406篇
特种医学   167篇
外科学   1084篇
综合类   531篇
一般理论   3篇
预防医学   369篇
眼科学   152篇
药学   460篇
  5篇
中国医学   207篇
肿瘤学   418篇
  2024年   10篇
  2023年   74篇
  2022年   82篇
  2021年   192篇
  2020年   187篇
  2019年   182篇
  2018年   170篇
  2017年   171篇
  2016年   186篇
  2015年   224篇
  2014年   283篇
  2013年   352篇
  2012年   458篇
  2011年   466篇
  2010年   368篇
  2009年   345篇
  2008年   381篇
  2007年   397篇
  2006年   402篇
  2005年   297篇
  2004年   287篇
  2003年   244篇
  2002年   231篇
  2001年   93篇
  2000年   76篇
  1999年   42篇
  1998年   44篇
  1997年   34篇
  1996年   27篇
  1995年   22篇
  1994年   16篇
  1993年   16篇
  1992年   21篇
  1991年   24篇
  1990年   15篇
  1989年   11篇
  1988年   3篇
  1987年   6篇
  1985年   5篇
  1984年   5篇
  1983年   4篇
  1982年   4篇
  1980年   5篇
  1979年   9篇
  1974年   7篇
  1973年   2篇
  1972年   2篇
  1970年   6篇
  1968年   2篇
  1966年   2篇
排序方式: 共有6504条查询结果,搜索用时 15 毫秒
101.
勃起功能障碍和前列腺增生症是中老年男性最为常见的2种非肿瘤性疾病,且发病率随着年龄的增长而升高.现代研究表明,勃起功能障碍和前列腺增生之间有着密切相关性,两者可同时发病,但是目前中医对于勃起功能障碍合并前列腺增生的研究较少,且临床上尚无令人满意的治疗方法.中医学认为年老肾虚,瘀血内阻为其主要的病因病机,肾虚为本,瘀血为标,因此,临证以补肾益气,活血化瘀为基本治法,往往能够取得较好的效果.故从"肾虚血瘀"论治前列腺增生合并勃起功能障碍值得从临床方面来作进一步的探讨.  相似文献   
102.

Research question

Previous studies of aromatase inhibitors on male infertility have focused on men with low testosterone–oestradiol ratio of less than 10. Can aromatase inhibitors improve spermatogenesis in men with idiopathic male infertility with normal testosterone–oestradiol ratio?

Design

Prospective study of men with idiopathic severe oligozoospermia (sperm concentration <5 million/ml) carried out between February 2015 and March 2017. The objective was to assess if semen-analysis parameters improved after treatment with letrozole. Secondary objectives were to monitor the safety of letrozole in men, and to measure the alterations in serum FSH, LH, oestradiol and testosterone levels.

Results

Fifteen men with normal testosterone–oestradiol ratio (>10) were treated with letrozole 2.5 mg daily for 4 months. This produced a 5.5-fold increase in sperm concentration (P?=?0.0068). All men had increased total serum testosterone and suppressed oestradiol levels after treatment, thus raising the overall testosterone–oestradiol ratio (P < 0.0001). Adverse effects from letrozole were relatively minor and included loss of libido (54%), headaches (25%), fatigue (21%), weakness (13%), loss of hair (8%) and dry mouth (8%).

Conclusions

Letrozole improves sperm concentration and increases testosterone–oestradiol ratio for men with oligozoospermia who have normal testosterone–oestradiol ratio; its role in the treatment of male infertility may be extended to this group of patients. In addition, it is a relatively well-tolerated drug with no serious adverse effects.  相似文献   
103.
104.
Acute aortic syndrome is a group of life-threatening diseases of the thoracic aorta that usually present to the emergency department. It includes aortic dissection, aortic intramural hematoma, and penetrating aortic ulcer. Rare aortic pathologies of aorto-esophageal fistula and mycotic aneurysm may also be included in this list. All these conditions require urgent treatment with complex clinical care and management. Most patients who present with chest pain are evaluated with a chest radiograph in the emergency department. It is important that maximum diagnostic information is extracted from the chest radiograph as certain signs on the chest radiograph are extremely useful in pointing towards the diagnosis of acute aortic syndrome.  相似文献   
105.
A clinical diagnosis of asthma is often considered when a child presents with recurrent cough, wheeze and breathlessness. However, there are many other causes of wheeze in a young child. These range from recurrent viral infections to chronic suppurative lung disease, gastro-oesophageal reflux disease and rare structural abnormalities. Arriving at a diagnosis includes taking into consideration the symptomatology, triggers, atopic features, family history, absence of red flags and therapeutic trial, where indicated.  相似文献   
106.
107.
108.
Background contextVariability in classifying and selecting levels of fusion in adolescent idiopathic scoliosis (AIS) has been repeatedly documented. Several computer algorithms have been used to classify AIS based on the geometrical features, but none have attempted to analyze its treatment patterns.PurposeTo use self-organizing maps (SOM), a kind of artificial neural networks, to reliably classify AIS cases from a large database. To analyze surgeon's treatment pattern in selecting curve regions to fuse in AIS using Lenke classification and SOM.Study designThis is a technical concept article on the possibility and benefits of using neural networks to classify AIS and a retrospective analysis of AIS curve regions selected for fusion.Patient sampleA total of 1,776 patients surgically treated for AIS were prospectively enrolled in a multicentric database. Cobb angles were measured on AIS patient spine radiographies, and patients were classified according to Lenke classification.Outcome measuresFor each patient in the database, surgical approach and levels of fusion selected by the treating surgeon were recorded.MethodsA Kohonen SOM was generated using 1,776 surgically treated AIS cases. The quality of the SOM was tested using topological error. Percentages of prediction of fusion based on Lenke classification for each patient in the database and for each node in the SOM were calculated. Lenke curve types, treatment pattern, and kappa statistics for agreement between fusion realized and fusion recommended by Lenke classification were plotted on each node of the map.ResultsThe topographic error for the SOM generated was 0.02, which demonstrates high accuracy. The SOM differentiates clear clusters of curve type nodes on the map. The SOM also shows epicenters for main thoracic, double thoracic, and thoracolumbar/lumbar curve types and transition zones between clusters. When cases are taken individually, Lenke classification predicted curve regions fused by the surgeon in 46% of cases. When those cases are reorganized by the SOM into nodes, Lenke classification predicted the curve regions to fuse in 82% of the nodes. Agreement with Lenke classification principles was high in epicenters for curve types 1, 2, and 5, moderate in cluster for curve types 3, 4, and 6, and low in transition zones between curve types.ConclusionsAn AIS SOM with high accuracy was successfully generated. Lenke classification principles are followed in 46% of the cases but in 82% of the nodes on the SOM. The SOM highlights the tendency of surgeons to follow Lenke classification principles for similar curves on the SOM. Self-organizing map classification of AIS could be valuable to surgeons because it bypasses the limitations imposed by rigid classification such as cutoff values on Cobb angle to define curve types. It can extract similar cases from large databases to analyze and guide treatment.  相似文献   
109.
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