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   1736篇
  免费   55篇
  国内免费   8篇
耳鼻咽喉   72篇
儿科学   83篇
妇产科学   135篇
基础医学   124篇
口腔科学   73篇
临床医学   136篇
内科学   326篇
皮肤病学   14篇
神经病学   86篇
特种医学   71篇
外科学   448篇
综合类   30篇
预防医学   37篇
眼科学   50篇
药学   56篇
中国医学   3篇
肿瘤学   55篇
  2024年   2篇
  2023年   6篇
  2022年   20篇
  2021年   31篇
  2020年   25篇
  2019年   41篇
  2018年   40篇
  2017年   30篇
  2016年   48篇
  2015年   69篇
  2014年   83篇
  2013年   107篇
  2012年   149篇
  2011年   151篇
  2010年   68篇
  2009年   88篇
  2008年   148篇
  2007年   173篇
  2006年   160篇
  2005年   115篇
  2004年   95篇
  2003年   59篇
  2002年   35篇
  2001年   15篇
  2000年   7篇
  1999年   11篇
  1998年   3篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1991年   2篇
  1990年   5篇
  1989年   1篇
  1988年   1篇
  1983年   1篇
  1975年   1篇
  1974年   1篇
排序方式: 共有1799条查询结果,搜索用时 15 毫秒
81.
82.
Breast cancer is the most frequent cancer among females and also a leading cause of cancer related mortality worldwide. A multimodality treatment approach may be utilized for optimal management of patients with combinations of surgery, radiation therapy (RT) and systemic treatment. RT composes an integral part of breast conserving treatment, and is typically used after breast conserving surgery to improve local control. Recent years have witnessed significant improvements in the discipline of radiation oncology which allow for more focused and precise treatment delivery. Adaptive radiation therapy (ART) is among the most important RT techniques which may be utilized for redesigning of treatment plans to account for dynamic changes in tumor size and anatomy during the course of irradiation. In the context of breast cancer, ART may serve as an excellent tool for patients receiving breast irradiation followed by a sequential boost to the tumor bed. Primary benefits of ART include more precise boost localization and potential for improved normal tissue sparing with adapted boost target volumes particularly in the setting of seroma reduction during the course of irradiation. Herein, we provide a concise review of ART for breast cancer in light of the literature.  相似文献   
83.
Background Macular edema is one of the most common causes of visual loss in patients with retinal vein oclusions. Intravitreal corticosteroids and intravitreal anti-vascular endothelial growth factors are modalities of treatment for macular edema secondary to branch retinal vein occlusion (BRVO). Objective To present the results of intravitreal triamcinolone acetonide therapy in patients with macular edema secondary to BRVO. Setting A retrospective clinical interventional study included 32 patients with macular edema secondary to BRVO. Method The records of 32 eyes of 32 patients who received 4 mg/0.1 mL injection of intravitreal triamcinlone for macular edema secondary to BRVO were evaluated. Patients with visual acuity <0.40 logMAR (logarithm of the minimum angle of resolution), central macular thickness (CMT) >260 μm and no neovascularization at baseline were included. Patients with diabetes mellitus, a history of intravitreal anti vascular endothelial growth factor injection, grid laser photocoagulation and ischemic BRVO were excluded. The re-injections were performed in cases with increased CMT >100 μm or vision loss of five or more letters. Results The mean follow-up was 12 ± 1.9 months. The visual acuity increased from 0.58 ± 0.16 at baseline to 0.25 ± 0.11 logMAR (P < 0.001). The CMT decreased from 490 ± 107 μm at baseline to 266 ± 90 μm at 12 months (P < 0.001). Both cataract and glaucoma developed in 18.75 % patients. Conclusion Intravitreal triamcinolone, due to absence of systemic side effects, can be used with confidence for treatment macular edema secondary to BRVO. However the main disadvantages of intravitreal triamcinolone injection are elevation of intraocular pressure and formation of cataract.  相似文献   
84.
85.
Determination of risk of severe bacterial infection complication in children with cancer is important to diminish the cost of hospitalization and therapy. In this study, children with cancer (leukemia excluded) were evaluated for risk of severe infection complication, success of therapy and the relation between clinical and inflammatory parameters during neutropenic fever attacks. Children who fulfilled the criteria of neutropenic fever with cancer were enrolled in the study. During admission, together with clinical and laboratory parameters; interleukin-6, interleukin-8, soluble tumor necrosis factor receptor II, and soluble interleukin 2 reseptor ve procalcitonin levels were detected. Empirical therapy was started with piperacillin/tazobactam and relation between the inflammatory cytokine levels and therapy response parameters were evaluated. The study population included 31 children and 50 neutropenic attacks were studied. In 48% of the attacks, absolute neutrophile count was >100/mm3 and infectious agents were shown microbiologically in 12% of the attacks. In the study group with piperacillin/tazobactam monotherapy, the success rate without modification was 58%. In the therapy modified group mean duration of fever, antibiotherapy and hospitalization were significantly longer than the group without modification. Inflammatory cytokines’ levels during admission (interleukin-6, interleukin-8, soluble tumor necrosis factor reseptor II) were higher in patients with fever >3 days and in multiple regression analysis, it has been shown that they have a determinative role on fever control time. Other cytokines did not show any significant relationship with risk of severe bacterial infection complication and success of therapy.  相似文献   
86.

Introduction

The aim of this study was to test the dentinal tubule penetration of AH26 (Dentsply DeTrey, Konstanz, Germany) and MTA Fillapex (Angelus, Londrina, PR, Brazil) in instrumented root canals obturated by using cold lateral compaction or warm vertical compaction techniques in either the presence or absence of the smear layer.

Methods

Forty-five extracted single-rooted human mandibular premolar teeth were used. The crowns were removed, and the root canals were instrumented by using the Self-Adjusting File (ReDent-Nova, Ra'anana, Israel) with continuous sodium hypochlorite (2.6%) irrigation. Final irrigation was either with 5% EDTA or with sodium hypochlorite. The canals were dried and obturated by using rhodamine B–labeled AH26 or MTA Fillapex in combination with the cold lateral compaction or the warm vertical compaction technique. After setting, the roots were sectioned horizontally at 4-, 8-, and 12-mm distances from the apical tip. On each section, sealer penetration in the dentinal tubules was measured by using confocal laser scanning microscopy.

Results

Regardless of the usage of EDTA, MTA Fillapex, compared with AH26, was associated with greater sealer penetration when used with the cold lateral compaction technique, and, conversely, AH26, compared with MTA Fillapex, was associated with greater sealer penetration when used with the warm vertical compaction technique (P < .05). Removal of the smear layer increased the penetration depth of MTA Fillapex used with the cold lateral compaction technique (P < .05); however, it had no significant effect on the penetration depth of AH26.

Conclusions

Greater sealer penetration could be achieved with either the MTA Fillapex–cold lateral compaction combination or with the AH26–warm vertical compaction combination. Smear layer removal was critical for the penetration of MTA Fillapex; however, the same did not hold for AH26.  相似文献   
87.
88.
INTRODUCTION: The aim of this study was to compare serum levels of leptin in women with unexplained infertility with fertile subjects. MATERIAL AND METHOD: Serum leptin levels of 27 infertile and 30 fertile women on day 3 of the menstrual cycle were assessed and compared in this prospective age and body mass index (BMI) comparable controlled study. RESULTS: The mean age in the infertile group was 29.3 (range, 23-38), while this figure was 28.9 (range, 19-39) in the fertile group; the mean BMIs were 24.5 (range, 20.6-27.8) and 25.0 (range, 21.8-28.7), respectively. The mean serum leptin level was significantly higher in women with unexplained infertility compared with fertile subjects. Considering normal weight subjects, mean serum leptin levels were increased significantly in the unexplained infertile group compared with the fertile group (7.2 (range, 4.3-10.4) versus 3.5 (range, 1.9-6.2)ng/ml, respectively; p<0.0001, Mann-Whitney U-test). The significant increase in serum leptin levels was observed also in overweight patients (6.8 (range, 1.3-5.2) versus 3.3 (range, 4.2-8.9)ng/ml, respectively; p<0.0001, Mann-Whitney U-test). CONCLUSION: A significant difference in serum leptin levels between unexplained infertile and fertile women suggests that this cytokine may be involved in pathophysiology of unexplained infertility.  相似文献   
89.
Thromboembolic disease associated with assisted reproductive techniques is extremely rare. A 21-year-old woman with primary infertility underwent an ovulation induction cycle with luteal long protocol. Twenty-four hours following oocyte retrieval, the patient complained of difficulty in speaking. On neurological examination, mild disorientation, motor aphasia, and right-sided hypoesthesia were noted. Brain computed tomography scanning without contrast revealed left parietal lob infarct. Brain magnetic resonance imaging (MRI), MRI angiography (MRA) and perfusion MRI demonstrated an occlusion of the posterior division of the left middle cerebral artery (MCA). Physical, ultrasound examinations and laboratory test evaluation failed to reveal ovarian hyperstimulation syndrome. Except for ovarian stimulation, no additional risk factors for stroke were shown. Following anticoagulation and speech therapy, the patient recovered completely within eight months. One year after the left MCA thrombosis, she conceived spontaneously and had an uncomplicated vaginal delivery of a live male infant weighing 2900 g at 38 weeks gestation. This case supports that ovulation induction and assisted reproductive techniques may be a newly recognized cause of cerebral infarction in otherwise healthy women.  相似文献   
90.
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