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   3955篇
  免费   239篇
  国内免费   21篇
耳鼻咽喉   17篇
儿科学   135篇
妇产科学   53篇
基础医学   454篇
口腔科学   221篇
临床医学   267篇
内科学   806篇
皮肤病学   49篇
神经病学   201篇
特种医学   121篇
外科学   629篇
综合类   101篇
一般理论   1篇
预防医学   275篇
眼科学   309篇
药学   374篇
中国医学   32篇
肿瘤学   170篇
  2024年   6篇
  2023年   37篇
  2022年   145篇
  2021年   201篇
  2020年   77篇
  2019年   117篇
  2018年   182篇
  2017年   133篇
  2016年   169篇
  2015年   143篇
  2014年   212篇
  2013年   239篇
  2012年   379篇
  2011年   270篇
  2010年   212篇
  2009年   156篇
  2008年   231篇
  2007年   241篇
  2006年   213篇
  2005年   159篇
  2004年   120篇
  2003年   110篇
  2002年   103篇
  2001年   30篇
  2000年   26篇
  1999年   28篇
  1998年   32篇
  1997年   15篇
  1996年   19篇
  1995年   14篇
  1994年   8篇
  1993年   11篇
  1992年   19篇
  1991年   21篇
  1990年   18篇
  1989年   21篇
  1988年   17篇
  1987年   21篇
  1986年   10篇
  1985年   9篇
  1984年   9篇
  1983年   4篇
  1982年   3篇
  1981年   2篇
  1979年   3篇
  1978年   6篇
  1977年   4篇
  1975年   2篇
  1972年   2篇
  1966年   2篇
排序方式: 共有4215条查询结果,搜索用时 11 毫秒
991.
Primary lumbar hernia is a rarely encountered hernia. Surgical correction is the standard treatment for lumbar hernia, and either an open or laparoscopic procedure can be performed with equivalent success. However, open repairs are most commonly performed. Here, we present a case of a primary lumbar hernia that was successfully treated laparoscopically and discuss surgical modalities of treatment reported in the literature. There are two laparoscopic approaches: transabdominal and extraperitoneal. The main advantage of the laparoscopic approach is that it helps the surgeon to precisely locate and evaluate the characteristics of the defect. It also has a lower morbidity rate, shorter length of hospital stay, less postoperative pain, and an earlier return to daily routine activities than the open approach. In the present study, a patient with a superior lumbar hernia was treated laparoscopically by the transabdominal approach. Laparoscopic repair in such cases is feasible and achieves a good result when done by an experienced laparoscopic hernia surgeon.  相似文献   
992.

Introduction

The persistence of dentin-bound lipopolysaccharides (LPS) in disinfected root canals impedes treatment outcomes of endodontic procedures. This study assessed the effects of photoactivated rose bengal–functionalized chitosan nanoparticles (CSRBnps) on LPS-contaminated root dentin in vivo using an intraosseous implantation model and neotissue formation as a marker.

Methods

Fifty human, 3-mm-long root segments with a 1.2-mm canal lumen were divided into 5 groups (n?=?10): group 1, canals not contaminated; group 2, canals contaminated with Pseudomonas aeruginosa LPS; group 3, canals contaminated and disinfected with sodium hypochlorite (NaOCl); group 4, canals contaminated and disinfected with NaOCl and calcium hydroxide; and group 5, canals contaminated and disinfected with NaOCl and CSRBnps (300?μg/mL) with photoactivation (λ?=?540?nm, 40?J/cm2). Specimens were implanted into mandibles of guinea pigs, block dissected after 4?weeks, and the canal content evaluated histologically and immunohistochemically. The ingrown neotissue interface (50?μm) with dentin was characterized for fibroblasts, osteoclasts, inflammatory markers, dentin resorption, mineralization, and angiogenesis and dichotomized as type 1 (no inflammation and resorption, indicative of LPS inactivation) or type 2 (inflammation and resorption). The frequency of the observed parameters was analyzed using the Fisher exact test.

Results

The outcome was categorized as type 1 in groups 1 and 5, type 2 in group 2, and mixed type 1 and 2 in groups 3 and 4. The outcomes in groups 1 and 5 (P?>?.05) differed significantly (P?<?.05) from those in groups 2, 3, and 4.

Conclusions

Disinfection of LPS-contaminated root canals with photoactivated CSRBnps in vivo supported ingrowth of neotissue without signs of inflammation or resorption, suggestive of effective inactivation of dentin-bound LPS.  相似文献   
993.

Introduction

The objective of this study was to determine the effect of delayed placement of the core/post and crown on the outcomes of nonsurgical root canal therapy (NSRCT).

Methods

According to the Delta Dental of Wisconsin claims database, 160,040 NSRCTs were completed with a core/post and a crown placed before the end of the continuous coverage period or occurrence of an untoward event. Untoward events were defined as a retreatment, apicoectomy, or extraction as defined by the Code on Dental Procedures and Nomenclature. Statistical analysis was performed by using a multivariable Cox proportional hazards model.

Results

The survival rate from the time of crown placement to an untoward event was 99.1% at 1 year, 96.0% at 3 years, 92.3% at 5 years, and 83.8% at 10 years. Failure rates were greater when a core/post was placed more than 60 days after the NSRCT (adjusted hazard ratio, 1.08) and when the crown was placed more than 60 days after the core/post placement (adjusted hazard ratio, 1.14). Overall, the survival rates of NSRCT were greater when performed by an endodontist versus other providers.

Conclusions

On the basis of the information available from insurance claims data, this study shows that the long-term survival rates of initial endodontic therapy are adversely affected by the delayed placement of the final restoration and full coverage crown.  相似文献   
994.
995.
Molecular Imaging and Biology - 4-[18F]Fluorobenzylguanidine ([18F]PFBG) is a positron emission tomography (PET) probe for non-invasive targeting of the norepinephrine transporter. The aim of this...  相似文献   
996.
In this study, we investigated the in vitro antifungal activities, cytotoxicities, and membrane-disruptive actions of amphiphilic tobramycin (TOB) analogues. The antifungal activities were established by determination of MIC values and in time-kill studies. Cytotoxicity was evaluated in mammalian cell lines. The fungal membrane-disruptive action of these analogues was studied by using the membrane-impermeable dye propidium iodide. TOB analogues bearing a linear alkyl chain at their 6″-position in a thioether linkage exhibited chain length-dependent antifungal activities. Analogues with C12 and C14 chains showed promising antifungal activities against tested fungal strains, with MIC values ranging from 1.95 to 62.5 mg/liter and 1.95 to 7.8 mg/liter, respectively. However, C4, C6, and C8 TOB analogues and TOB itself exhibited little to no antifungal activity. Fifty percent inhibitory concentrations (IC50s) for the most potent TOB analogues (C12 and C14) against A549 and Beas 2B cells were 4- to 64-fold and 32- to 64-fold higher, respectively, than their antifungal MIC values against various fungi. Unlike conventional aminoglycoside antibiotics, TOB analogues with alkyl chain lengths of C12 and C14 appear to inhibit fungi by inducing apoptosis and disrupting the fungal membrane as a novel mechanism of action. Amphiphilic TOB analogues showed broad-spectrum antifungal activities with minimal mammalian cell cytotoxicity. This study provides novel lead compounds for the development of antifungal drugs.  相似文献   
997.
The protozoan Trypanosoma cruzi triggers an inflammatory process in mammalian heart causing events such as fibrosis, changes in the architecture and functionality in this organ. Enalapril, an angiotensin II-converting enzyme inhibitor, is a drug prescribed to ameliorate this heart dysfunction, and appears to exert a potential role in immune system regulation. Our aim was to evaluate the chronic cardiac inflammatory parameters after therapeutic treatment with enalapril and benznidazole in C57BL/6 mice infected with the VL-10 strain of T. cruzi. After infection, animals were treated with oral doses of enalapril (25 mg/kg), benznidazole (100 mg/kg), or both during 30 days. Morphometric parameters and levels of chemokines (CCL2, CCL5), IL-10, creatine kinases (CKs), and C-reactive protein were evaluated in the heart and serum at the 120th day of infection. Enalapril alone or in combination with benznidazole did not change the number of circulating parasites, but reduced cardiac leukocyte recruitment and total collagen in the cardiac tissue. Interestingly, the combination therapy (enalapril/benznidazole) also reduced the levels of chemokines, CK and CK-MB, and C-reactive proteins in chronic phase. In conclusion, during the chronic experimental T. cruzi infection, the combination therapy using enalapril plus benznidazole potentiated their immunomodulatory effects, resulting in a low production of biomarkers of cardiac lesions.  相似文献   
998.

Background and Objectives:

Prehospital transport practices prevalent among children presenting to the emergency are under-reported. Our objectives were to evaluate the prehospital transport practices prevalent among children presenting to the pediatric emergency and their subsequent clinical course and outcome.

Methods:

In this prospective observational study we enrolled all children ≤17 years of age presenting to the pediatric emergency (from January to June 2013) and recorded their demographic data and variables pertaining to prehospital transport practices. Data was entered into Microsoft Excel and analyzed using Stata 11 (StataCorp, College Station, TX, USA).

Results:

A total of 319 patients presented to the emergency during the study period. Acute gastroenteritis, respiratory tract infection and fever were the most common reasons for presentation to the emergency. Seventy-three (23%) children required admission. Most commonly used public transport was auto-rickshaw (138, 43.5%) and median time taken to reach hospital was 22 min (interquartile range: 5, 720). Twenty-six patients were referred from another health facility. Of these, 25 were transported in ambulance unaccompanied. About 8% (25) of parents reported having difficulties in transporting their child to the hospital and 57% (181) of parents felt fellow passengers and drivers were unhelpful. On post-hoc analysis, only time taken to reach the hospital (30 vs. 20 min; relative risk [95% confidence interval]: 1.02 [1.007, 1.03], P = 0.003) and the illness nature were significant (45% vs. 2.6%; 0.58 [0.50, 0.67], P ≤ 0.0001) on multivariate analysis.

Conclusions:

In relation to prehospital transport among pediatric patients we observed that one-quarter of children presenting to the emergency required admission, the auto-rickshaw was the commonest mode of transport and that there is a lack of prior communication before referring patients for further management.  相似文献   
999.
Rapidly, establishing a difficult intravenous access in a dangerously agitated patient is a real challenge. Intranasal midazolam has been shown to be effective and safe for rapidly sedating patients before anesthesia, for procedural sedation and for control of seizure. Here, we report a patient in intensive care unit who was on mechanical ventilation and on inotropic support for management of septic shock and who turned out extremely agitated after accidental catheter removal. Intravenous access was successfully established following sedation with intranasal midazolam, using ultrasound guidance.  相似文献   
1000.
APOLT is a suitable technique of liver transplantation in patients with ALF and some types of MLD. Portal venous steal is a problem with this procedure that leads to graft dysfunction and failure. Modulation of the portal flow to the graft and native liver can help in preventing this problem. We discuss the pathophysiology of this complication, review available literature regarding its management, and describe our results using the technique of graded hemiportal banding to achieve adequate perfusion for the graft and native liver.  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