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   33811篇
  免费   3808篇
  国内免费   957篇
耳鼻咽喉   321篇
儿科学   414篇
妇产科学   387篇
基础医学   2037篇
口腔科学   9673篇
临床医学   2114篇
内科学   2485篇
皮肤病学   608篇
神经病学   624篇
特种医学   531篇
外国民族医学   3篇
外科学   1369篇
综合类   4148篇
现状与发展   3篇
预防医学   1894篇
眼科学   177篇
药学   7572篇
  30篇
中国医学   2438篇
肿瘤学   1748篇
  2024年   31篇
  2023年   630篇
  2022年   696篇
  2021年   1275篇
  2020年   1532篇
  2019年   1493篇
  2018年   1370篇
  2017年   1348篇
  2016年   1347篇
  2015年   1375篇
  2014年   2008篇
  2013年   2539篇
  2012年   2008篇
  2011年   2162篇
  2010年   1710篇
  2009年   1430篇
  2008年   1512篇
  2007年   1536篇
  2006年   1387篇
  2005年   1302篇
  2004年   1094篇
  2003年   1008篇
  2002年   846篇
  2001年   737篇
  2000年   659篇
  1999年   511篇
  1998年   435篇
  1997年   492篇
  1996年   370篇
  1995年   337篇
  1994年   340篇
  1993年   252篇
  1992年   294篇
  1991年   280篇
  1990年   238篇
  1989年   230篇
  1988年   204篇
  1987年   184篇
  1986年   159篇
  1985年   200篇
  1984年   201篇
  1983年   159篇
  1982年   134篇
  1981年   110篇
  1980年   80篇
  1979年   63篇
  1978年   51篇
  1977年   68篇
  1976年   46篇
  1975年   35篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
91.
The aim of this study was to evaluate the effectiveness and tolerance of an oral nutritional supplement that is highly concentrated in protein and energy in elderly subjects who are malnourished or at risk of malnutrition. Twenty-four subjects aged between 70 and 94 years old, who had lost an average of 8.2% of their body weight and whose intake was 70% lower than their requirements, received a nutritional supplement (Fortimel® Protein 200 mL, NUTRICIA) over a period of four weeks at a rate of two bottles per day (one unit providing 480 kcal and 29 g of protein). The analysis carried out at the end of this period showed a significant increase in muscular strength measured by hand grip [on average 19.5 ± 7.05 kg at D0 and 21.0 ± 8.1 kg at D28 (P = 0.002)]. The patients’ weight rose on average by 0.6 ± 1.9 kg (P = 0.08). Patient appetite improved overall as evidenced by the significant increase in spontaneous intake and dietary protein contribution. Overall health status as perceived by patients did not significantly improve. The product was well received by patients (median adherence rate of 93.5%) and generally well tolerated, even if certain patients complained about minor digestive disorders, which led to reduced adherence.  相似文献   
92.
本文主要总结朱启勇教授诊治复发性口疮的思路与经验,认为复发性口疮与脏腑的虚、实、寒、热密切相关,并将复发性口疮分为胃热证、肺阴虚证、脾虚证3种证型,分别给予清降胃热、养阴清热、健脾益气治疗。  相似文献   
93.
目的:观察复方黄柏液涂剂灌肠联合吲哚美辛栓纳肛治疗吻合器痔上黏膜环切术(Procedure for Prolapse and Hemorrhoids,PPH)术后肛门下坠的临床效果。方法:收集40例PPH术后1个月后出现肛门下坠患者并随机分为两组,治疗组20例,给予复方黄柏液涂剂灌肠联合吲哚美辛栓纳肛;对照组20例,单独给予吲哚美辛栓纳肛。7天为1个疗程,连续治疗2个疗程,观察治疗后的症状积分及治疗有效率。结果:两组患者治疗前肛门下坠评分比较,差异无统计学意义(P> 0.05);两组患者经过2个疗程的治疗,治疗前与治疗后的症状积分均有改善(P <0.05),2个疗程后治疗组的肛门下坠评分低于对照组(P <0.05)。治疗组总有效率为94.7%(18/19),低于对照组的78.9%(15/19),差异有统计学意义(P <0.05)。结论:复方黄柏液涂剂灌肠联合吲哚美辛栓治疗PPH术后肛门下坠比单独使用吲哚美辛栓效果明显,尤其是对肛门坠胀不适疼痛不明显者。  相似文献   
94.
目的分析乳酸清除率(LCR)、脉搏变异指数(PVI)与下腔静脉内径呼吸变异指数(IVCrvi)液体治疗对单肺通气老年全腔镜食管癌根治术患者血流动力学的影响。方法将拟行单肺通气全腔镜食管癌根治术的106例老年食管癌患者随机均分为对照组和观察组。对照组术中给予常规液体治疗,观察组术中给予以LCR、PVI与IVCrvi为目标导向的液体治疗。比较两组术前(T0)、单肺通气前(T1)、单肺通气15 min(T2)、单肺通气1 h(T3)及单肺通气结束时(T4)的心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)、每搏输出量变异度(SVV)和心脏指数(CI)。比较两组液体出入量及药物应用情况。同时记录术前和术后肺功能参数。结果两组各时间点HR比较差异均无统计学意义(P>0.05),观察组T2~T4时间点MAP、CI和SVV、LCR高于对照组,CVP、PVI、IVCrvi低于对照组(P<0.05)。观察组单肺通气时间、晶体液用量、总输液量、尿量、出血量及使用去氧肾上腺素占比低于对照组,胶体液用量高于对照组(P<0.05)。观察组术后第1秒用力呼气量(FEV1)、用力肺活量(FVC)、FEV1/FVC均高于对照组(P<0.05)。结论以LCR、PVI与IVCrvi为目标导向的液体治疗可稳定单肺通气老年患者全腔镜食管癌根治术患者的血流动力学。  相似文献   
95.
Objective: This study analyzed the health-seeking behavior of Filipinos using Google Trends tool to quantify relative search volume by term . Oral cancer, mouth cancer, tongue cancer, gum cancer, and lip cancer were used as predetermined search terms. Material and method: Comma-separated values file containing relative search volumes of search trends pertaining to oral cancer from 2009 to 2019 were assessed. Brown-Forsythe one-way ANOVA was used to measure differences with respect to oral cancer across different years and months. Two-way repeated measures ANOVA was applied to detect differences regarding mouth cancer, tongue cancer, gum cancer, and lip cancer across the years. Time series models were fitted and used to forecast search interests. Results: The results revealed that interest in oral cancer was significantly higher in 2019 (43.75±5.5, p <0.05) compared to 2009 (29.0 ± 6.7). In terms of months, searches were higher in February (45.0 ± 6.6) compared to May (24.8 ± 3.4, p=0.015), June (25.3 ± 4.4, p=0.020), and December (26.5 ± 4.0, p=0.038). Search interests for gum cancer and lip cancer remained significantly lower from 2011 to 2019, and tongue cancer from 2016 to 2018 but approximated mouth cancer in 2019. The forecast showed that mouth cancer (31.67%), tongue cancer (23.75%), and lip cancer (3.83%) would fluctuate through time pass, while gum cancer (8%) would remain steady in 2020. Conclusion: Health-seeking behavior through search trends showed an increased interest in oral cancer in 2019 and during February. It was anticipated that search interests would fluctuate in 2020, but at the end of the year would decrease for mouth cancer and tongue cancer, increase for lip cancer, and remain steady for gum cancer.  相似文献   
96.
97.
98.
The leaves of Rubus suavissimus (also called “Chinese sweet tea”) is used not only as a beverage tea and food additive but also as a folk herbal medicine for the treatment of diabetes mellitus. To systematically investigate its material foundation of efficacy for treating diabetes, herein, a hyphenated strategy by off-line coupling high-speed countercurrent chromatography, ultrafiltration HPLC-UV-MS and prep-HPLC was developed. And thus, α-glucosidase inhibitors from Rubus suavissimus leaves was comprehensively profiled, purified and characterized. As a result, twenty-six compounds were identified as potential α-glucosidase inhibitors and favorably isolated by prep-HPLC. Their structures were identified via UV, MS, and 1H-NMR. Notably, fourteen compounds, including protocatechuic acid (1), myketin (3), epicatechin (4), vanillic acid (6), apigenin (11), catechin (12), ferulic acid (15), luteolin (16), 3, 3′-di-O-methylellagic acid (17), chlorogenic acid (19), 3, 3′-di-O-methylellagic acid-4′-O-β-D-glucoside (20), cinnamic acid (21), syringate (24) and ethylbrevifolin-carboxylate (25), were reported in leaves of Rubus suavissimus for the first time. In addition, α-glucosidase inhibitory activities of compounds 1–26 were evaluated, and eighteen compounds exhibited stronger α-glucosidase inhibitory activities than acarbose (IC50 value at 214.24 ± 3.48 μg/mL, positive control). The results indicated that the proposed method is a highly efficient strategy for comprehensive profiling and purification of bioactive target compounds, including both major and minor components, from natural products.  相似文献   
99.
Iris Cervenka  Marie Al Rahmoun  Yahya Mahamat-Saleh  Agnès Fournier  Marie-Christine Boutron-Ruault  Gianluca Severi  Saverio Caini  Domenico Palli  Reza Ghiasvand  Marit B. Veierod  Edoardo Botteri  Anne Tjønneland  Anja Olsen  Renée T. Fortner  Rudolf Kaaks  Matthias B. Schulze  Salvatore Panico  Antonia Trichopoulou  Clio Dessinioti  Katerina Niforou  Sabina Sieri  Rosario Tumino  Carlotta Sacerdote  Bas Bueno-de-Mesquita  Torkjel M. Sandanger  Sandra Colorado-Yohar  Maria J. Sánchez  Leire Gil Majuelo  Leila Lujan-Barroso  Eva Ardanaz  Susana Merino  Karolin Isaksson  Salma Butt  Ingrid Ljuslinder  Malin Jansson  Ruth C. Travis  Kay-Tee Khaw  Elisabete Weiderpass  Laure Dossus  Sabina Rinaldi  Marina Kvaskoff 《International journal of cancer. Journal international du cancer》2020,146(12):3267-3280
Evidence suggests an influence of sex hormones on cutaneous melanoma risk, but epidemiologic findings are conflicting. We examined the associations between use of oral contraceptives (OCs) and menopausal hormone therapy (MHT) and melanoma risk in women participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). EPIC is a prospective cohort study initiated in 1992 in 10 European countries. Information on exogenous hormone use at baseline was derived from country-specific self-administered questionnaires. We used Cox proportional hazards regression models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). Over 1992–2015, 1,696 melanoma cases were identified among 334,483 women, whereof 770 cases among 134,758 postmenopausal women. There was a positive, borderline-significant association between OC use and melanoma risk (HR = 1.12, 95% CI = 1.00–1.26), with no detected heterogeneity across countries (phomogeneity = 0.42). This risk increased linearly with duration of use (ptrend = 0.01). Among postmenopausal women, ever use of MHT was associated with a nonsignificant increase in melanoma risk overall (HR = 1.14, 95% CI = 0.97–1.43), which was heterogeneous across countries (phomogeneity = 0.05). Our findings do not support a strong and direct association between exogenous hormone use and melanoma risk. In order to better understand these relations, further research should be performed using prospectively collected data including detailed information on types of hormone, and on sun exposure, which may act as an important confounder or effect modifier on these relations.  相似文献   
100.
目的:建立高效液相色谱-荧光检测法测定性早熟女童血浆中双酚A和4-壬基酚含量的方法。方法:采用Shim-pack VP-ODS C18色谱柱(150 mm×4.6 mm,5 μm),流动相为乙腈∶水=70∶30,流速1 mL/min,柱温30 ℃,检测激发波长275 nm,发射波长315 nm,外标法定量检测血浆中双酚A和4-壬基酚含量。结果:双酚A和4-壬基酚分别在1.45~5 937.50 ng/mL (r2=0.999 9,n=7),1.53~6 250.00 ng/mL(r2=0.998 8,n=7)范围内线性关系良好;日内、日间RSD均<7.83%,方法回收率均>94.6%。结论:本法简便、快速、灵敏、准确,适用于同时测定性早熟女童血浆中双酚A和4-壬基酚的含量和临床血样常规检测。  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