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   15354篇
  免费   1534篇
  国内免费   664篇
耳鼻咽喉   54篇
儿科学   122篇
妇产科学   327篇
基础医学   2852篇
口腔科学   442篇
临床医学   1111篇
内科学   1948篇
皮肤病学   166篇
神经病学   1176篇
特种医学   675篇
外国民族医学   2篇
外科学   997篇
综合类   3034篇
现状与发展   4篇
一般理论   1篇
预防医学   970篇
眼科学   106篇
药学   1548篇
  44篇
中国医学   859篇
肿瘤学   1114篇
  2024年   16篇
  2023年   894篇
  2022年   1202篇
  2021年   1200篇
  2020年   1349篇
  2019年   922篇
  2018年   724篇
  2017年   733篇
  2016年   813篇
  2015年   896篇
  2014年   1173篇
  2013年   964篇
  2012年   833篇
  2011年   692篇
  2010年   788篇
  2009年   763篇
  2008年   434篇
  2007年   481篇
  2006年   419篇
  2005年   364篇
  2004年   289篇
  2003年   252篇
  2002年   157篇
  2001年   184篇
  2000年   120篇
  1999年   212篇
  1998年   186篇
  1997年   132篇
  1996年   107篇
  1995年   20篇
  1994年   50篇
  1993年   18篇
  1992年   20篇
  1991年   18篇
  1990年   21篇
  1989年   3篇
  1988年   9篇
  1987年   3篇
  1986年   4篇
  1985年   10篇
  1984年   14篇
  1983年   5篇
  1982年   4篇
  1981年   8篇
  1979年   7篇
  1978年   10篇
  1977年   6篇
  1976年   5篇
  1975年   2篇
  1974年   9篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
目的 了解我国老年人中医证候分布特征,为中医药辨治老年人提供参考依据。方法 系统检索中国知识基础设施(CNKI)、中文科技期刊数据库(CCD)、万方数据资源系统数据库(CSPD),纳入研究对象为老年人的临床流行病学调查研究文献,对其调查目的、调查疾病及调查结果等进行描述统计。结果 ①最终纳入168篇文献,其中2010至2020年之间发表138篇(82.14%);调查地区涵盖全国28个省市自治区,共纳入43948例老年人,累计覆盖340个研究中心;②主要研究结果显示,老年人中医证候阴虚阳亢证(10.05%)>血瘀证(9.5%)>痰浊(湿)证(8.91%)>阴阳两虚证(4.98%)>痰瘀互结证(4.96%);单元证分布阴虚证(14.70%)>痰证(11.22%)>气虚证(7.15%)>肾虚证(4.72%)>血瘀证(4.18%);涉及病变脏腑肾>肝>脾>肺>心。结论 根据统计结果,可以看出老年人证候分布虚证多于实证,虚证中又以阴虚证、气虚证最为多见,实证常见血瘀证、痰浊(湿)证等,且多见痰瘀互结证;老年人五脏皆损,其中又以肾、肝、脾功能失调最为突出。  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.
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   
5.
6.
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   
7.
8.
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   
9.
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   
10.
This study aimed to characterize a stable nano-niosome formulation, which could reduce the adverse effects of carboplatin (CB) and improve its therapeutic efficacy in the treatment of breast cancer. For this purpose, CB-loaded polyethylene glycol (PEG)ylated niosome nanoparticles (PEG-NS-CB) were synthesized using the reverse-phase evaporation method. PEG-NS-CB (226.0 ± 10.6 nm) could release CB in a controlled manner and, compared to CB and CB-loaded non-PEGylated niosome (NS-CB), caused higher cytotoxicity effects against mouse breast cancer 4T1 cells (IC50: 83.4, 26.6, and 22.5 µM for CB, NS-CB, and PEG-NS-CB, respectively). Also, PEG-NS-CB demonstrated higher stability, in which its profile of drug release, cytotoxicity, and LE% did not change significantly three months after preparation compared to those at the production time. In addition, the in vivo results demonstrated that PEG-NS-CB caused higher therapeutic (the number of alive mice: 12, 15, and 17 out of 20 in CB, NS-CB, and PEG-NS-CB receiver groups, respectively) and less toxicity effects (weight loss of 17, 12.5, and 10% in CB, NS-CB, and PEG-NS-CB receiver groups, respectively), compared to NS-CB and CB in breast cancer-bearing mice. Overall, the results of this study suggest that PEG-NS-CB could be a promising formulation for the treatment of breast cancer.  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