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   1636篇
  免费   83篇
  国内免费   8篇
耳鼻咽喉   24篇
儿科学   103篇
妇产科学   101篇
基础医学   170篇
口腔科学   87篇
临床医学   151篇
内科学   356篇
皮肤病学   47篇
神经病学   121篇
特种医学   62篇
外科学   233篇
综合类   15篇
预防医学   65篇
眼科学   56篇
药学   78篇
中国医学   1篇
肿瘤学   57篇
  2024年   1篇
  2023年   28篇
  2022年   33篇
  2021年   74篇
  2020年   26篇
  2019年   58篇
  2018年   44篇
  2017年   51篇
  2016年   70篇
  2015年   73篇
  2014年   90篇
  2013年   115篇
  2012年   141篇
  2011年   133篇
  2010年   77篇
  2009年   84篇
  2008年   112篇
  2007年   103篇
  2006年   94篇
  2005年   108篇
  2004年   75篇
  2003年   50篇
  2002年   42篇
  2001年   8篇
  2000年   5篇
  1999年   6篇
  1998年   6篇
  1997年   7篇
  1995年   1篇
  1994年   1篇
  1992年   2篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
排序方式: 共有1727条查询结果,搜索用时 62 毫秒
81.
82.

Purpose  

In this study, we aimed to compare the effects of ropivacaine alone and ropivacaine plus tramadol administered epidurally for postoperative analgesia in children.  相似文献   
83.
The objective is to compare the success rates of revision endonasal dacryocystorhinostomy (END-DCR) with revision external dacryocystorhinostomy (EXT-DCR). The present retrospective study was conducted between January 2002 and July 2009. Seventy-four consecutive patients (17 males, 57 females) who had epiphora or recurrent dacryocystitis after a previous failed EXT-DCR procedure were enrolled in the study. The END-DCR group consisted of 43 patients (10 males, 33 females) who underwent 44 END-DCRs, whereas the EXT-DCR group included 31 patients (7 males, 24 females) who underwent 31 dacryocystorhinostomies (DCRs). Successful DCR was defined as relief of symptoms as demonstrated by saline irrigation at the last post-operative visit. Further nasal surgery was performed in 18 (40.9%) eyes in the END-DCR group. The average follow-up time for the END-DCR and EXT-DCR groups was 11 and 9?months, respectively. The success rate was 77.4% (24/31 DCRs) in the END-DCR group, and 84.1% (37/44 DCRs) in the EXT-DCR group. There was no significant difference between the groups regarding overall success (p?=?0.465). END-DCR is as safe and efficient technique as external approach with low complication rates in revision cases. END-DCR yields good esthetic and functional results and has a success rate similar to that of the external approach.  相似文献   
84.
BACKGROUND AND OBJECTIVE: To assess the surgical outcomes of the use of tissue glue to close sclerotomy sites when required and the views of ultrasound biomicroscopy of the sclerotomy sites in 23- and 25-gauge vitrectomy systems. PATIENTS AND METHODS: A 25-gauge transconjunctival sutureless vitrectomy was performed in 38 eyes and a 23-gauge transconjunctival sutureless vitrectomy was performed in 46 eyes for various vitreoretinal diseases. Wound leakage occurred at the sclerotomy sites at the end of the surgery in 6 eyes with 23-gauge transconjunctival sutureless vitrectomy and 7 eyes with 25-gauge transconjunctival sutureless vitrectomy. The sclerotomy sites were closed by using tissue glue to prevent wound leakage and evaluated with ultrasound biomicroscopy postoperatively. RESULTS: No wound leakage was observed at the end of the surgical procedure or during the follow-up period. Abnormal fibrous ingrowth was not detected at the sclerotomy sites by means of ultrasound biomicroscopy. CONCLUSION: The results demonstrated the efficacy of tissue glue for closing site ports when wound leakage is observed in transconjunctival sutureless vitreoretinal surgery.  相似文献   
85.
The pp60c‐Src is one of the ubiquitously expressed Src family kinases and has important functions in malignant cells, including regulation of cell division, growth factor signaling, and movement. Therefore, investigating new small molecule inhibitors of pp60c‐Src is important to discover and develop novel therapeutics for cancer and metastasis. Moreover, some of the small molecule inhibitors that do not qualify for therapeutic use may become very useful tool to explore the role of Src kinase in normal cells as well as in a variety of disease models. Our continuous efforts to find novel inhibitors of pp60c‐Src aimed for therapeutic and research use, we synthesized newly designed aminomethylindole derivatives as novel small molecule inhibitors and investigated their inhibitory effect on pp60c‐Src tyrosine kinase. Here, we report one potential inhibitor of the pp60c‐Src from five active molecules of all nine compounds, which were synthesized and screened for the biological activity of the molecules against pp60c‐Src target.  相似文献   
86.
Reproductive failure and anti-sperm antibody (ASA) production among prostitutes were investigated. A questionnaire including the subject's age, years of prostitution, date of most recent birth, number of children and contraceptive method used at the beginning of prostitution were asked of 109 prostitutes, but only 53 agreed to complete the questionnaire. ASA was detected by ELISA in the prostitutes (n = 109) and in the control group (n = 40) sera. The tests revealed a high ASA rate (43.1%) among the prostitutes. The difference in the incidence of ASA between controls (5%) and the prostitutes (43.1%) was highly significant (p less than 0.01). It was found that ASA positivity incidence in 27 prostitutes who had never use any contraception method and who became infertile within 9.3 years (average) was 61.3%. These results may be explained by repeatedly inoculations with multiple sperm antigens and/or microorganisms.  相似文献   
87.
In this study 23 patients with various gynaecological pathologies were evaluated. Ultrasonography and magnetic resonance imaging were performed in all cases, but only 14 were evaluated with computed tomography. On the basis of ultrasonography, 4 patients were labelled as having malignant ovarian tumours, however, this diagnosis was confirmed by magnetic resonance imaging in only 1 of the 4. Magnetic resonance imaging also determined the correct diagnosis in a patient with endometrioma whereas computed tomography showed only a simple cyst, and ultrasonography diagnosed a subserous myoma. Tumour was demonstrated by magnetic resonance imaging in 2 patients with cervical carcinoma although computed tomography and ultrasonography had previously shown no tumour mass in these patients. It was concluded that magnetic resonance imaging is much superior to computed tomography and ultrasonography in gynaecological diagnosis. This advantage results from the correct detection of the contents of ovarian cysts, the number and localization of uterine leiomyomas in T2 scans, invasion of uterine malignancies and differential diagnosis of subserous uterine leiomyomas from ovarian tumours.  相似文献   
88.
OBJECTIVE: The object of this study was to investigate the genotoxic effect of acute overexposure to combustion products originating from coal or wood stoves in patients presenting with acute carbon monoxide intoxication. STUDY DESIGN: In a prospective study, we analyzed the frequency of sister chromatid exchange and the carboxyhemoglobin concentration in 20 consecutive patients without a history of smoking or drug use who had been treated in the Emergency Care Unit of Istanbul Medical Faculty due to acute carbon monoxide intoxication. All of these cases were domestic accidents due to dysfunctioning coal or wood stoves. The results were compared with a control group of 20 nonsmoking, nondrug-using healthy individuals matched for age, sex, and absence of other chemical exposure. RESULTS: The mean sister chromatid exchange frequency per metaphase was significantly higher in the study group compared to the control group: 8.11 +/- 2.39 vs. 6.33 +/- 1.60 (p = 0.008). We found that there was no positive correlation between the blood carboxyhemoglobin concentration and sister chromatid exchange frequency. CONCLUSIONS: These results suggest that acute exposure to combustion products of wood or coal is genotoxic to DNA. Potential causes of genotoxicity include known mutagenic compounds present in coal or wood smoke and ash, oxygen radicals formed during combustion, as well as hypoxic and reperfusion injury mechanisms initiated by carbon monoxide intoxication. Additional studies on separate carbon monoxide exposure from smoke and ash are needed to understand individual genotoxic contributions and mechanisms.  相似文献   
89.
Is the Cell Death in Mesial Temporal Sclerosis Apoptotic?   总被引:6,自引:0,他引:6  
PURPOSE: Mesial temporal sclerosis (MTS) is characterized by neuronal loss in the hippocampus. Studies on experimental models and patients with intractable epilepsy suggest that apoptosis may be involved in neuronal death induced by recurrent seizures. METHODS: We searched evidence for apoptotic cell death in temporal lobes resected from drug-resistant epilepsy patients with MTS by using the terminal deoxynucleotidyl transferase (TdT) and digoxigenin-11-dUTP (TUNEL) method and immunohistochemistry for Bcl-2, Bax, and caspase-cleaved actin fragment, fractin. The temporal lobe specimens were obtained from 15 patients (six women and nine men; mean age, 29 +/- 8 years). RESULTS: Unlike that in normal adult brain, we observed Bcl-2 immunoreactivity in some of the remaining neurons dispersed throughout the hippocampus proper as well as in most of the reactive astroglia. Bax immunopositivity was increased in almost all neurons. Fractin immunostaining, an indicator of caspase activity, was detected in approximately 10% of these neurons. Despite increased Bax expression and activation of caspases, we could not find evidence for DNA fragmentation by TUNEL staining. We also could not detect typical apoptotic changes in nuclear morphology by Hoechst-33258 or hematoxylin counterstaining. CONCLUSIONS: These data suggest that either apoptosis is not involved in cell loss in MTS, or a very slow rate of cell demise may have precluded detecting TUNEL-positive neurons dying through apoptosis. Increased Bax expression and activation of caspases support the latter possibility.  相似文献   
90.
Bone healing regulated by nitric oxide: an experimental study in rats   总被引:12,自引:0,他引:12  
Nitric oxide has many functions in wound healing and metabolism of bone. In the current study the role of nitric oxide on bone healing was investigated. Thirty-six young adult male Sprague-Dawley rats were divided into three groups: control, nitroso-bovine serum albumin, and aminoguanidine. Five millimeter segmental defects were created in the middle of the right femora. A polyethylene plate and screw posts were used for rigid fixation. Demineralized bone matrix served as the graft material in all groups. Nitroso-bovine serum albumin (an active nitric oxide congener) carried by demineralized bone matrix was applied locally at the defect in the nitroso-bovine serum albumin group. Aminoguanidine (an inducible nitric oxide synthase inhibitor) group received oral aminoguanidine treatment. Formation and healing of bone were determined by radiographic and histologic analyses. In comparison to the control group the healing rate was faster in both experimental groups as indicated by radiographic and histologic data. If accompanied by bone graft with a suitable delivery system, nitric oxide may be useful as a therapeutic adjuvant in clinical situations when local formation of bone is needed. Moreover, when combined appropriately, treatment with orthotopic nitric oxide supplementation and systemic inducible nitric oxide synthase inhibition may enhance bone healing.  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