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   7705篇
  免费   613篇
  国内免费   15篇
耳鼻咽喉   100篇
儿科学   165篇
妇产科学   262篇
基础医学   1169篇
口腔科学   171篇
临床医学   799篇
内科学   1518篇
皮肤病学   183篇
神经病学   770篇
特种医学   247篇
外科学   1087篇
综合类   63篇
一般理论   5篇
预防医学   545篇
眼科学   218篇
药学   627篇
中国医学   17篇
肿瘤学   387篇
  2023年   56篇
  2022年   75篇
  2021年   166篇
  2020年   102篇
  2019年   156篇
  2018年   181篇
  2017年   128篇
  2016年   138篇
  2015年   144篇
  2014年   196篇
  2013年   337篇
  2012年   397篇
  2011年   355篇
  2010年   226篇
  2009年   198篇
  2008年   323篇
  2007年   355篇
  2006年   308篇
  2005年   286篇
  2004年   297篇
  2003年   268篇
  2002年   262篇
  2001年   239篇
  2000年   246篇
  1999年   195篇
  1998年   80篇
  1997年   67篇
  1995年   72篇
  1994年   69篇
  1993年   55篇
  1992年   170篇
  1991年   195篇
  1990年   154篇
  1989年   148篇
  1988年   142篇
  1987年   154篇
  1986年   138篇
  1985年   141篇
  1984年   112篇
  1983年   94篇
  1982年   66篇
  1981年   49篇
  1980年   52篇
  1979年   111篇
  1978年   74篇
  1977年   60篇
  1976年   55篇
  1975年   47篇
  1974年   46篇
  1973年   46篇
排序方式: 共有8333条查询结果,搜索用时 15 毫秒
961.
To assess whether gallstone patients with duodenal diverticula have bacterial overgrowth in the proximal small bowel, the results of the 1-g 14C-D-xylose breath test were compared in 24 patients with duodenal diverticula and in 24 without diverticula. All patients had been treated with endoscopic papillotomy (EPT) for stones in the common bile duct before the study, and cholecystectomy had previously been performed in 20 patients. No significant differences between the groups were found concerning age, sex, and body weight. Cumulative 14CO2 expired in 3 h in percentage of administered dose of 14C-D-xylose was 8.55% (7.58-9.57%) and 7.38% (6.32-8.96%) in patients with and without diverticula, respectively (p = 0.06), indicating a higher bacterial activity in the small bowel in patients with duodenal diverticula than in those without diverticula. The results appeared to be influenced by cholecystectomy.  相似文献   
962.

Background  

Sodium retention and ascites are serious clinical problems in cirrhosis. Urodilatin (URO) is a peptide with paracrine effects in decreasing sodium reabsorption in the distal nephron. Our aim was to investigate the renal potency of synthetic URO on urine sodium excretion in cirrhosis patients with sodium retention and ascites.  相似文献   
963.
Relationship of overweight to hiatus hernia and reflux oesophagitis   总被引:14,自引:0,他引:14  
In a prospective study in 1224 patients referred for upper alimentary endoscopy, reflux oesophagitis was found in 195 (16%) of the patients and hiatus hernia in 249 (20%). In patients with reflux oesophagitis a coexisting hiatus hernia was found in 68%. The weight-for-height index (W/H1.8), which expresses the degree of overweight, was significantly higher both in patients with hiatus hernia and in the patients with reflux oesophagitis, indicating an overweight of approximately 5% in both groups. The overweight was most pronounced in oesophagitis grades 1 and 2, whereas in patients with severe oesophagitis (grade 3) body weight was normal, possibly owing to weight loss caused by dysphagia and excessive regurgitation. The results support the view that adiposity is associated with both sliding hiatus hernia and reflux oesophagitis and that hiatus hernia plays a role in the development of reflux oesophagitis.  相似文献   
964.
Meconium aspiration syndrome (MAS) is a cause of significant morbidity and mortality in the perinatal period. Despite the clinical relevance of MAS, its pathogenesis is poorly understood. Epithelial cell-derived prostanoids are involved in the regulation of several cellular functions within the lung, including the control of tone and reactivity of airway and vascular smooth muscle. In this study, we evaluated whether exposure to meconium affects the metabolic function of human airway epithelial cells. Monolayers of A549 cells, a transformed human epithelial cell line, were incubated with various concentrations of meconium. Control cells were incubated with serum-free medium in a similar manner. The supernatant fluid was removed at various time points and assayed for thromboxane A(2) (TXA(2)) production. The latter was accomplished by measuring its immediate and stable metabolite thromboxane B(2), using an enzyme-linked immunosorbent assay (ELISA). In selected experiments, the modulatory effects of indomethacin (10(-6) M), dexamethasone (10(-6) M), and L-nitroarginine methyl ester (L-NAME, 10(-6) M) on TXA(2) production were evaluated. Results were expressed in terms of pg/mg protein (mean +/- SE). We found that exposure to meconium produced a significant release of TXA(2) from A549 cells. Indomethacin, dexamethasone, and in part, L-NAME inhibited meconium-induced release of TXA(2). Our findings demonstrate that meconium enhances the production of thromboxanes from A549 cells, suggesting that airway epithelial cells and their metabolic products may play an important role in the pathogenesis of MAS.  相似文献   
965.
Static web pages may be easy to setup using text processors or user-friendly web editing software. However, some basic knowledge of the implementation (HTML) is usually needed for final editing and maintenance. As a result many static web pages are left without appropriate updating. With a database driven, dynamic approach web contents may change through user interaction, the pages are usually easier to maintain, and design elements are separated from contents. Database driven solutions (or content management systems) for larger organizations may be purchased at many different levels of complexity. For smaller systems, such as separate courses or projects, they may, however, be developed locally. The present study compares four alternative technologies for database driven web pages. Each technology offers advantages and disadvantages and many issues need to be considered when selecting platform. The present study demonstrates that database driven web pages may be effectively deployed using free Open Source software. Details may be found at www.intermed.dk/datadriven.  相似文献   
966.
967.
It is well established that cultured endothelial cells are induced to generate tissue factor activity when incubated with either endotoxin or thrombin. In this study a perfusion system was used on 3-4 cm long human saphenous veins. The veins were perfused with thrombin (2.5 U/ml), endotoxin (30 ng/ml) or just medium for 3 h at 37 degrees C. After the perfusion, the veins were treated with collagenase, and EC were collected and subjected to tissue factor activity measurements. Some perfused veins were examined for tissue factor activity on the vessel wall by allowing factor VII and factor X to interact with the lumen of the intact vessels, followed by quantitation of generated factor Xa in a chromogenic assay. No formation of tissue factor activity could be found after perfusion in either collagenase-dissolved endothelial cells or in the coupled chromogenic assay for tissue factor activity performed in the lumen of the vessel. Our data strongly suggest that endothelial cells in intact endothelium may behave quite differently from isolated endothelial cells stimulated in cell cultures.  相似文献   
968.

Aims

This study examined delayed type one diabetes (T1D) diagnosis, along with the associated severity markers, in the United States. Qualitative reflection was explored to add depth of understanding.

Methods

975 parents of a minor child with T1D were recruited through snowball, social media requests to complete a 55-question online survey on the experience of diagnosis.

Results

34% of children with T1D had a delayed diagnosis. When compared to those without a delayed diagnosis, these children were more likely to have an Emergency Room diagnosis (39.8% vs. 24.6%), be transported by ambulance or life flight (30.7% vs. 15.3%), be hospitalized (93.7% vs. 83.9%), spend time in an Intensive Care Unit (42.2% vs. 21.3%), and be in diabetic ketoacidosis (DKA) (42.2% vs. 21.3%). Younger children were at increased risk, with higher rates of DKA and fewer days of symptoms. Many parents experienced frustration receiving a prompt diagnosis for their child, including an inability to schedule a physician appointment, proper glucose testing, and concerns being dismissed by professionals.

Conclusion

More physician and parent education is needed. Doctors should conduct glucose screenings when diabetes symptoms are present. Parents need education to recognize excessive thirst and frequent urination as reasons to seek medical treatment.  相似文献   
969.
970.
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