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   19561篇
  免费   1746篇
  国内免费   868篇
耳鼻咽喉   67篇
儿科学   215篇
妇产科学   469篇
基础医学   3899篇
口腔科学   691篇
临床医学   1451篇
内科学   2732篇
皮肤病学   254篇
神经病学   1817篇
特种医学   808篇
外国民族医学   2篇
外科学   1456篇
综合类   2408篇
现状与发展   6篇
一般理论   2篇
预防医学   1243篇
眼科学   124篇
药学   2040篇
  24篇
中国医学   831篇
肿瘤学   1636篇
  2024年   42篇
  2023年   972篇
  2022年   1291篇
  2021年   1441篇
  2020年   1538篇
  2019年   1031篇
  2018年   884篇
  2017年   958篇
  2016年   978篇
  2015年   1117篇
  2014年   1606篇
  2013年   1344篇
  2012年   1095篇
  2011年   1061篇
  2010年   1155篇
  2009年   1039篇
  2008年   499篇
  2007年   577篇
  2006年   532篇
  2005年   349篇
  2004年   270篇
  2003年   234篇
  2002年   210篇
  2001年   169篇
  2000年   157篇
  1999年   237篇
  1998年   212篇
  1997年   149篇
  1996年   158篇
  1995年   151篇
  1994年   117篇
  1993年   98篇
  1992年   80篇
  1991年   63篇
  1990年   72篇
  1989年   56篇
  1988年   37篇
  1987年   21篇
  1986年   16篇
  1985年   24篇
  1984年   24篇
  1983年   12篇
  1982年   10篇
  1981年   12篇
  1979年   14篇
  1978年   15篇
  1977年   11篇
  1976年   8篇
  1974年   7篇
  1967年   5篇
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
1.
The purpose of this study was to investigate the association between habitual snoring (HS), middle ear disease (MED), and speech problems in children with cleft palate. This cross-sectional study included children aged 2.0–7.9 years with non-syndromic cleft palate anomalies. Parents completed the Pediatric Sleep Questionnaire and a questionnaire about MED. Audiograms and speech assessment were also conducted. Ninety-five children were enrolled; 15.2% of families reported HS, 97.6% MED, and 17.1% speech problems. HS (37.5% vs 10.3%, P = 0.007) and early episodes of MED (92.3% vs 58.2%, P = 0.021) were more likely to be reported for children with isolated cleft palate when compared to those with cleft lip and palate. Children with cleft lip and palate had a higher frequency of MED with effusion compared to those with Robin sequence (86.4% vs 57.1%, P = 0.049). The odds ratio for HS in children with ≥1 episode of MED in the last year was 7.37 (95% confidence interval 1.55–35.15, P = 0.012). There was a trend for children with speech problems reported by parents to have HS (30.8% vs 11.5%, P= 0.076). Anatomical factors play a role in the frequency of upper airway symptoms in children with cleft palate. A recent history of at least one episode of MED was associated with an increased frequency of HS.  相似文献   
2.
A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system.  相似文献   
3.
In forensic medicine, although various alcohols have been reported as indicators of decomposition in collected blood, no studies have examined short-chain fatty acids as indicators. In this study, the blood n-butyric acid concentration was quantified, and the association between n-butyric acid and decomposition was investigated to determine whether the detection of n-butyric acid could be a new indicator of decomposition. Among the forensic autopsies performed from 2016 to 2018 in our laboratory, the cases were divided into decomposed (n = 20) and non-decomposed (n = 20) groups based on macroscopic findings. Blood samples collected at the time of autopsy were derivatized with 3-nitrophenylhydrazine hydrochloride after solid-phase extraction. The n-butyric acid concentration was measured using liquid chromatography–tandem mass spectrometry. In addition, ethanol and n-propanol were measured using a gas chromatography-flame ionization detector. There was a significant difference (p < 0.01) in the concentrations of n-butyric acid between the decomposed and non-decomposed groups (0.343 ± 0.259 [0.030–0.973] and 0.003 ± 0.002 [0.001–0.007] mg/mL, respectively). In the decomposed group, n-butyric acid was detected at high concentrations, even in cases where n-propanol was low. These results suggest that n-butyric acid is more likely to be an indicator of blood decomposition than n-propanol.  相似文献   
4.
5.
BackgroundRhythmic joint mobilizations (RJM) of the temporomandibular joint (TMJ) are employed to relieve pain and improve function in patients with temporomandibular disorders (TMD). However, the evidence on the immediate effects of RJM in patients with TMD is scarce. The aim of this study was to assess the immediate clinical and functional effects of RJM in patients with TMD.Materials and methodsThis was a one-group quasi-experimental before and after study. Thirty-eight patients with TMD were assessed by means of pain intensity (visual analogue score, VAS), pressure pain threshold (PPT, measured through pressure algometry on the masseter and temporal muscles), mouth opening (MO, measured with a ruler), and surface electromyographic activity of the masseter and temporal muscles (asymmetry index, AI). Measurements were performed before and after a single, 1-min session of RJM of each TMJ. All statistical analyses were performed using the SPSS version 20.0 statistical package.ResultsA statistical significant difference was found in pain intensity, PPT and MO after the intervention (p < 0.05). No difference was found in the AI. A large effect size was observed for pain intensity, PPT of the left and right masseter muscles and MO (d = 0.85–1.13), whereas for the left and right temporal muscles the effect size was moderate (d = 0.62) and small, respectively (d = 0.49).ConclusionIn this sample of patients with TMD, a single session of RJM of the TMJ seemed to be effective in reducing pain intensity, increasing PPT and improving MO immediately after the intervention, without differences in the AI.  相似文献   
6.
7.
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments.  相似文献   
8.
9.
BackgroundSafe pharmaceutical care requires competent nurses with specific knowledge, skills and attitudes. It is unclear whether nursing students are adequately prepared to perform pharmaceutical care in practice. Mapping their pharmaceutical care competences can lead to a better understanding of the extent to which curricula fit expectations of the labour market.ObjectivesTo assess pharmaceutical care competences of final-year nursing students of different educational levels.DesignA cross-sectional survey design.SettingsIn 14 European countries, nursing schools who offer curricula for level 4 to 7 students were approached.ParticipantsThrough convenience sampling 1741 final-year student nurses of level 4 to 7 were included. Sampling strategies were country-specific.MethodsA web-platform was developed with an assessment of the level in which students mastered pharmaceutical care competences. Knowledge questions, case studies (basic/advanced level), self-reported practical skills and attitudes were evaluated.ResultsMean scores for knowledge questions differed significantly (p < 0.001) between level 5 (56/100), level 6 (68/100) and level 7 students (72/100). For basic cases level 5 students reached lower scores (64/100) compared with level 6 (71/100) and level 7 (72/100) students (p = 0.002 and p = 0.005). For more advanced cases no difference between levels was observed (overall mean 61/100). Most students (63–90 %) considered themselves skilled to perform pharmaceutical care and had positive attitudes towards their participation in pharmaceutical care (65–97 %).ConclusionsRelatively low knowledge scores were calculated for final-year student nurses. In some domains, lower levels of students might be insufficiently prepared to take up responsibilities in pharmaceutical care. Our assessment can be used as a tool for educators to evaluate how prepared nursing students are for pharmaceutical care. Its further implementation for students of different educational levels will allow benchmarking between the levels, both within and between countries.  相似文献   
10.
Oxidative stress and inflammation are two possible mechanisms related to nephrotoxicity caused by environmental pollutants. Ellagic acid, a powerful antioxidant phytochemical, may have great relevance in mitigating pollutant-induced nephrotoxicity and preventing the progression of kidney disease. This review discusses the latest findings on the protective effects of ellagic acid, its metabolic derivatives, the urolithins, against kidney toxicity caused by heavy metals, pesticides, mycotoxins, and organic air pollutants. We describe the chelating, antioxidant, anti-inflammatory, antifibrotic, antiautophagic, and antiapoptotic properties of ellagic acid to attenuate nephrotoxicity. Furthermore, we present the molecular targets and signaling pathways that are regulated by these antioxidants, and suggest some others that should be explored. Nevertheless, the number of reports is still limited to establish the efficacy of ellagic acid against kidney damage induced by environmental pollutants. Therefore, additional preclinical studies on this topic are required, as well as the development of well-designed clinical trials.  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