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   6670篇
  免费   642篇
  国内免费   67篇
耳鼻咽喉   62篇
儿科学   168篇
妇产科学   116篇
基础医学   829篇
口腔科学   544篇
临床医学   713篇
内科学   1301篇
皮肤病学   57篇
神经病学   571篇
特种医学   234篇
外科学   1038篇
综合类   147篇
一般理论   15篇
预防医学   637篇
眼科学   66篇
药学   502篇
中国医学   34篇
肿瘤学   345篇
  2021年   97篇
  2020年   68篇
  2019年   106篇
  2018年   118篇
  2017年   94篇
  2016年   98篇
  2015年   114篇
  2014年   186篇
  2013年   256篇
  2012年   306篇
  2011年   408篇
  2010年   216篇
  2009年   169篇
  2008年   335篇
  2007年   412篇
  2006年   387篇
  2005年   344篇
  2004年   305篇
  2003年   318篇
  2002年   305篇
  2001年   131篇
  2000年   153篇
  1999年   114篇
  1998年   93篇
  1997年   74篇
  1996年   74篇
  1995年   71篇
  1994年   49篇
  1992年   97篇
  1991年   75篇
  1990年   91篇
  1989年   64篇
  1988年   81篇
  1987年   75篇
  1986年   84篇
  1985年   69篇
  1984年   70篇
  1983年   72篇
  1982年   52篇
  1981年   48篇
  1980年   41篇
  1979年   45篇
  1978年   61篇
  1977年   59篇
  1976年   39篇
  1975年   46篇
  1974年   48篇
  1973年   41篇
  1972年   52篇
  1971年   41篇
排序方式: 共有7379条查询结果,搜索用时 78 毫秒
21.
A plasmid-borne gene mediating trimethoprim resistance, dhfrIX, newly found among porcine strains of Escherichia coli, was observed at a frequency of 11% among trimethoprim-resistant veterinary isolates. This rather high frequency of dhfrIX could be due to the extensive use of trimethoprim in veterinary practice in Sweden. After searching several hundred clinical isolates, one human E. coli strain was also found to harbor the dhfrIX gene. Thus, the dhfrIX gene seems to have spread from porcine bacteria to human pathogens. Furthermore, the occurrence of other genes coding for resistant dihydrofolate reductase enzymes (dhfrI, dhfrII, dhfrV, dhfrVII, and dhfrVIII) among the porcine isolates was investigated. In addition, association of dhfr genes with the integraselike open reading frames of transposons Tn7 and Tn21 was studied. In colony hybridization experiments, both dhfrI and dhfrII were found associated with these integrase genes. The most common combination was dhfrI and int-Tn7, indicating a high prevalence of Tn7.  相似文献   
22.
23.
BACKGROUND: The presence of a comorbid tic disorder may predict a poorer outcome in the acute treatment of pediatric obsessive-compulsive disorder (OCD). METHODS: Using data from the National Institute of Mental Health (NIMH)-funded Pediatric OCD Treatment Study (POTS) that compared cognitive-behavior therapy (CBT), medical management with sertraline (SER), and the combination of CBT and SER (COMB), to pill placebo (PBO) in children and adolescents with OCD, we asked whether the presence of a comorbid tic disorder influenced symptom reduction on the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) after 12 weeks of treatment. RESULTS: Fifteen percent (17 of 112) of patients exhibited a comorbid tic disorder. In patients without tics, results replicated previously published intent-to-treat outcomes: COMB > CBT > SER > PBO. In patients with a comorbid tic disorder, SER did not differ from PBO, while COMB remained superior to CBT and CBT remained superior to PBO. CONCLUSIONS: In contrast to CBT outcomes, which are not differentially impacted, tic disorders appear to adversely impact the outcome of medication management of pediatric OCD. Children and adolescents with obsessive-compulsive disorder and a comorbid tic disorder should begin treatment with cognitive-behavior therapy alone or the combination of cognitive-behavior therapy plus a serotonin reuptake inhibitor.  相似文献   
24.
25.
26.
肌病肾病代谢综合征治疗进展   总被引:1,自引:0,他引:1  
肌病肾病代谢综合征是急性动脉阻塞致骨骼肌溶解的严重并发症。积极治疗原发病,及早补液扩容、碱化尿液、早期血液净化治疗是降低截肢率、病死率的关键。本文就肌病肾病代谢综合征治疗进展作一综述。  相似文献   
27.
Obsessive-compulsive disorder (OCD) is a distressing and functionally impairing disorder that can emerge as early as age 4. Cognitive behavior therapy (CBT) for OCD in youth shows great promise for amelioration of symptoms and associated functional impairment. However, the empirical evidence base for the efficacy of CBT in youth has some significant limitations, particularly as related to treating the very young child with OCD. This report includes a quantitative review of existing child CBT studies to evaluate evidence for the efficacy of CBT for OCD. It identifies gaps in the literature that, when addressed, would enhance the understanding of effective treatment in pediatric OCD. Finally, it presents a proposed research agenda for addressing the unique concerns of the young child with OCD.  相似文献   
28.
肝尾状叶由于解剖位置特殊,位置深,难以显露,手术难度大,是肝脏外科领域手术操作的难点与研究热点.随着肝血流控制技术的发展、肝实质离断技术的提高,肝尾状叶肿瘤切除率明显提高[1].2006年4月至2008年10月,我科完成单独肝尾状叶血管瘤切除术9例,现将手术技巧与疗效报道如下.  相似文献   
29.
30.
BACKGROUND AND OBJECTIVES: Laparoscopy in patients with poor cardiac function has been the subject of controversy and is considered by many surgeons a relative contraindication. METHODS: We report the case of a patient who presented with acute cholecystitis and choledocholithiasis concurrent with unstable angina. Our experience in laparoscopic management of patients with calculous biliary disease and severe coronary artery disease is examined. RESULTS: The patient was managed by coronary angioplasty and stenting immediately followed by laparoscopic cholecystectomy and common bile duct exploration under close invasive hemodynamic monitoring and low-pressure pneumoperitoneum. Between 1996 and 2001, 39 patients with coronary artery disease and an ASA class of III or IV underwent laparoscopic cholecystectomy. Eight of these patients (20.5%) had common bile duct stones necessitating laparoscopic common bile duct exploration. No conversions were necessary, and no major morbidity or mortalities occurred. CONCLUSIONS: Laparoscopic cholecystectomy and common bile duct exploration can be safely performed in patients with severe ischemic cardiac disease under close hemodynamic monitoring and a low-pressure pneumoperitoneum (10 to 12 mm Hg).  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