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   12673篇
  免费   628篇
  国内免费   112篇
耳鼻咽喉   314篇
儿科学   637篇
妇产科学   529篇
基础医学   925篇
口腔科学   418篇
临床医学   1015篇
内科学   3240篇
皮肤病学   193篇
神经病学   748篇
特种医学   542篇
外科学   3011篇
综合类   171篇
一般理论   1篇
预防医学   292篇
眼科学   449篇
药学   453篇
中国医学   23篇
肿瘤学   452篇
  2024年   11篇
  2023年   110篇
  2022年   208篇
  2021年   389篇
  2020年   247篇
  2019年   306篇
  2018年   381篇
  2017年   307篇
  2016年   524篇
  2015年   600篇
  2014年   655篇
  2013年   787篇
  2012年   1028篇
  2011年   929篇
  2010年   570篇
  2009年   487篇
  2008年   841篇
  2007年   990篇
  2006年   903篇
  2005年   886篇
  2004年   785篇
  2003年   586篇
  2002年   527篇
  2001年   64篇
  2000年   32篇
  1999年   46篇
  1998年   56篇
  1997年   40篇
  1996年   27篇
  1995年   24篇
  1994年   15篇
  1993年   7篇
  1992年   8篇
  1991年   10篇
  1990年   9篇
  1989年   4篇
  1988年   2篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
  1973年   2篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
PURPOSE: To evaluate the necessity of draining more than one hepatic duct in malignant hilar obstructions. MATERIALS AND METHODS: Two hundred seventeen self-expandable uncovered metallic stents (144 biliary Wallstents and 73 Memotherm nitinol stents) were placed percutaneously in 138 patients with unresectable malignant hilar obstructions. The patients included 76 men and 62 women, with a median age of 76 years (range, 43-82 years). Single-duct drainage was achieved in 74 patients (54%) by placing one stent (n = 59) or by placing an additional stent inserted telescopically through the first one (n = 15) to achieve an adequate stent length for long strictures (group 1). In 64 patients (46%), to maintain two-duct drainage, two stents were inserted through dual transhepatic tracts in a "Y" configuration (n = 41; group 2Y) or a single transhepatic tract in a "T" configuration (n = 23; group 2T). RESULTS: The overall technical success rate was 100%, and early clinical response was obtained in 89% of patients. The overall rate of major complications was 5.7% and did not show a statistically significant difference among groups 1, 2Y, and 2T in Bismuth type II, III, and IV obstructions. The patency rate was not statistically significant among groups 1, 2Y, and 2T in Bismuth type II and III obstructions (P >.05). However, in Bismuth type IV obstructions, the patency rate was significantly higher in group 2Y (P =.03; Kruskal-Wallis test). CONCLUSION: There is no need to place more than one stent in Bismuth type I, II, and III hilar obstructions. In Bismuth type IV obstructions, deployment of two parallel stents through dual transhepatic tracts should be performed.  相似文献   
72.
73.
IntroductionEosinophilic airway inflammation is a recognized inflammatory pattern in subgroups of patients with chronic obstructive pulmonary disease (COPD). However, there are still conflicting results between various studies concerning the effect of eosinophils in COPD patients. Our aim with this study was to evaluate eosinophilic inflammation and its relation to the clinical characteristics in a group of COPD patients.MethodsStable COPD patients with FEV1% predicted < 50 or with ≥ 1 exacerbation leading to hospital admission or ≥2 moderate or severe exacerbation history were consecutively enrolled from outpatient clinics.ResultsWe included 90 male COPD patients, with a mean age of 63.3 ± 9.2. Mean FEV1% predicted was 35.9 ± 11.3. Eosinophilic inflammation (eosinophil percentage ≥2%) was evident in 54 (60%) of the patients. Participants with eosinophilic inflammation were significantly older and had better FEV1 predicted % values. Eosinophilic COPD patients were characterized with better quality of life and fewer symptoms. COPD patients with noneosinophilic inflammation used supplemental long‐term oxygen therapy (LTOT) more frequently compared to patients with eosinophilic inflammation (36.1% vs. 14.8%, p = 0.01). Eosinophilic inflammation is associated with less dyspnea severity measured by mMRC (OR: 0.542 95% CI: 0.342–0.859, p = 0.009) and less LTOT use (OR: 0.334 95% CI: 0.115–0.968, p = 0.04) regardless of age, severity of airflow limitation, and having frequent exacerbation phenotype.ConclusionOur study supports the growing evidence for a potential role of eosinophilic inflammation phenotype in COPD with distinctive clinical characteristics. Eosinophilic inflammation is inversely associated with dyspnea severity measured by mMRC and LTOT use independently from age, total number of exacerbations, St. George Respiratory Questionnaire (SGRQ) total score and FEV1% predicted.  相似文献   
74.
目的 探讨血清胱抑素(Cyst-C)、尿微量白蛋白/肌酐(UmAlb/UCr)对高血压患者早期肾损害的诊断价值.方法 根据肾动态显像结果将85例原发性高血压患者分为早期肾功能损害组(A组)32例和单纯高血压组(B组)53例,并选取健康体检者50例为对照组,采用酶联免疫法测定各组Cyst-C、UmAlb/UCr、血清尿素氮(BUN)、血清肌酐(Scr)含量.结果 与对照组相比,A组及B组Cyst-C、UmAlb/UCr水平显著升高,B组则高于A组,差异有统计学意义(P<0.05),而三组BUN、Scr水平比较差异无统计学意义(P>0.05).随着高血压分级的增加,Cyst-C、UmAlb/UCr水平显著上升,其中Ⅲ级组患者显著高于Ⅰ级组及Ⅱ级组,差异有统计学意义(P.<0.05).Cyst-C灵敏性、特异性、准确性分别为81.6%、82.3%、69.2%,UmAlb/UCr灵敏性、特异性、准确性分别为84.5%、83.4%、76.9%,而UmAlb/UCr+Cyst-C灵敏性、特异性、准确性分别为93.2%、91.3%、92.3%.B组Cyst-C与UmAlb/UC联合检测阳性率显著高于单纯UmAlb/UCr或Cyst-C检测,差异有统计学意义(P<0.05).结论 Cyst-C与UmAlb/UC联合检测有助于高血压患者早期肾损害的诊断.  相似文献   
75.
76.
Aims: The aim of this study is to investigate the effect of mitral stenosis (MS) on left atrial (LA) function using two‐dimensional speckle tracking echocardiography (2DSTE). Methods and Results: The study subjects consisted of 52 patients with asymptomatic MS and 52 control subjects. LA function was assessed using prototype speckle tracking software and manual tracking method. Maximal LA volume (LAVmax) and minimal LA volume (LAVmin) and LA volume before atrial contraction (LAVpre‐a) were measured. Using these volumes, LA reservoir, conduit and booster pump fuction parameters were calculated. Indexed LAVmax, LAVmin, and LAVpre‐a measurements via speckle tracking were highly correlated with manual tracing methods in both groups. Expansion index (67.8 ± 36.4 vs. 148.3 ± 44.2), diastolic emptying index (37.7 ± 12.9 vs. 58.0 ± 8.5), passive emptying (37.3 ± 14.1 vs. 70.4 ± 10.4) and passive emptying index (13.3 ± 6.3 vs. 41.3 ± 10.6) were decreased significantly in MS patients (P < 0.001). In contrast active emptying index (62.6 ± 4.1 vs. 29.5 ± 10.1) increased in MS group (P < 0.001) while active emptying (28.1 ± 13.0 vs. 28.3 ± 6.9) remained same among both groups. Conclusions: This is the first study relating LA volumes and function assessed by 2DSTE to MS. 2D speckle tracking analysis of LA volume is relatively easy and provides more detailed information regarding the changes in LA volumes during the cardiac cycle.  相似文献   
77.
78.
In the present study, the contents of Zn, Fe, Cu, Mn, Co, Ni, Pb, Cd, Cr, Al, Ca, Mg, and K in Agaricus campestris, Agrocybe cylindracea, Collybia dryophila, Helvella leucopus, Russula delica, Tricholoma auratum, Amanita ovoidea, Melanoleuca excissa, Rhizopogon roseolus, Russula chloroides, Volvoriella gloiocephala, Lyophyllum decastes, Morcella angusticeps, Morchella esculenta and Morcella eximia collected from Isparta, Mugla, and Osmaniye provinces (Turkey) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave digestion. The intake of heavy metals (Pb, Cd) and other metals (Fe, Cu, Zn) by consumption of 30 g dry weight of mushrooms daily poses no risk at all except in A. cylindracea and H. leucopus (for Cd) for the consumer.  相似文献   
79.
80.
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