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   17109篇
  免费   1289篇
  国内免费   658篇
耳鼻咽喉   69篇
儿科学   232篇
妇产科学   46篇
基础医学   1628篇
口腔科学   531篇
临床医学   1230篇
内科学   1817篇
皮肤病学   417篇
神经病学   946篇
特种医学   408篇
外国民族医学   2篇
外科学   969篇
综合类   2597篇
现状与发展   2篇
预防医学   789篇
眼科学   359篇
药学   5793篇
  24篇
中国医学   879篇
肿瘤学   318篇
  2024年   107篇
  2023年   187篇
  2022年   393篇
  2021年   617篇
  2020年   544篇
  2019年   455篇
  2018年   431篇
  2017年   455篇
  2016年   501篇
  2015年   488篇
  2014年   1003篇
  2013年   1220篇
  2012年   1060篇
  2011年   1041篇
  2010年   899篇
  2009年   772篇
  2008年   771篇
  2007年   807篇
  2006年   736篇
  2005年   652篇
  2004年   610篇
  2003年   536篇
  2002年   433篇
  2001年   376篇
  2000年   300篇
  1999年   260篇
  1998年   242篇
  1997年   238篇
  1996年   238篇
  1995年   211篇
  1994年   194篇
  1993年   160篇
  1992年   144篇
  1991年   134篇
  1990年   127篇
  1989年   130篇
  1988年   121篇
  1987年   86篇
  1986年   92篇
  1985年   253篇
  1984年   180篇
  1983年   172篇
  1982年   152篇
  1981年   147篇
  1980年   104篇
  1979年   70篇
  1978年   56篇
  1977年   38篇
  1976年   34篇
  1975年   32篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
目的探讨双醋瑞因与玻璃酸钠关节腔内注射治疗膝关节骨关节炎(OA)的疗效。方法选取门诊及住院膝关节OA患者120例,随机分为双醋瑞因组和玻璃酸钠组,应用平均WOMAC关节炎指数评分和平均OA严重程度指数来评定2组用药前后临床症状改善情况以及关节磁共振成像(MRI)检测关节软骨结构与功能的改变情况,并作统计学分析。结果平均WOMAC关节炎指数和平均OA严重程度指数评分变化,玻璃酸钠组治疗后3,6个月较双醋瑞因组改善明显(P均〈0.01);治疗后12个月持续下降,但以玻璃酸钠组为甚,2组间比较有显著性差异(P〈0.05),且2组与治疗前比较均有显著性差异(P均〈0.01);治疗6个月后,玻璃酸钠组与双醋瑞因组较治疗前软骨磨损出现明显好转与减少(P均〈0.01),2组间无显著性差异(P〉0.05)。结论双醋瑞因与玻璃酸钠关节腔内注射均为治疗膝关节OA有效手段,玻璃酸钠较双醋瑞因改善症状明显,远期疗效改善软骨磨损无差异。  相似文献   
62.
The impact of selenium on the course of Hashimoto’s thyroiditis (HT) was mainly assessed by monitoring the titer of antithyroid autoantibodies in most of the studies conducted hitherto. On the other hand, the imbalance in activity of T cells such as Th1, Th2, Th17, and Treg may be relevant in the pathogenesis of this disease. Hence, the assessment of changes in the secretion of cytokines by these cells during selenium supplementation in patients with HT seems to be an important issue and was the main goal of this study. A further aim was to search for correlations among these cytokines, as well as markers of thyroid function, selenium/iodine status in the body, and other biochemical parameters. The group of 29 women with newly diagnosed Hashimoto’s thyroiditis was supplemented with selenium in a dose of 100 µg/day for 6 months. Immunological parameters: interferon γ, tumor necrosis factor α, chemokine CXCL10, interleukin 4, interleukin 1β, interleukin 17, transforming growth factor β, and C-reactive protein, as well as selenium status parameters were determined in serum twice, i.e., before and after supplementation. Selenium supplementation was associated with a change in the production of two cytokines: interferon γ and interleukin 1β, for which a decrease and an increase in concentration were observed, respectively. The partial least squares (PLS) model revealed the presence of many relevant correlations among analyzed parameters. The stage of HT development, degree of thyroid dysfunction, and selenium supplementation of diet are interdependent factors which shape the profile of some cytokines secreted by cells participating in the autoimmunity process.  相似文献   
63.
The excess sodium (Na) intake and insufficient potassium (K) intake are frequently observed all over the world, including Indonesia. This study explored the dietary patterns of Indonesian people and evaluated their associations with Na and K intakes. Na and K intakes were assessed by repeated 24-h urine collection. The dietary patterns of the previous month were extracted by factor analysis using the Indonesian Food Frequency Questionnaire. The participants were community-dwelling Indonesian men and women (n = 479) aged 20 years and over. We identified four dietary patterns in each sex. After controlling for confounding factors, the high quantile of ‘Noodle, oil, and salty sea products’ pattern was associated with the high Na intake in both men and women (p = 0.02 and <0.001, respectively). The ‘Meat, vegetable, oil, and fruit’ pattern statistically significantly contributed to the high K intake in men (p = 0.04), but not in women (p = 0.26). The ‘Vegetable, non-oil, and milk’ pattern in men and ‘Meat, vegetable, and fruit’ pattern in women were associated with low Na:K ratios (p = 0.03 and 0.01, respectively). Neither ‘bread’ nor ‘fish’ appeared as a major determinant of any dietary patterns in this population. The ‘Noodle, oil, and salty sea products’ pattern should be avoided to reduce sodium intake.  相似文献   
64.
目的:探索凝胶材料配比对丁香罗勒油透皮凝胶体外透皮性能的影响。方法:以CMC-Na和PVA为辅料,制备丁香罗勒油透皮剂。采用改良Franz扩散池,以鼠背皮肤为屏障进行经皮渗透试验,以丁香酚含量为指标,通过气相色谱法检测丁香罗勒油的经皮渗透量。结果:CMC-Na和PVA总量对丁香罗勒油透皮能力有较大影响,以25%为最佳;CMC-Na和PVA的比例对丁香罗勒油透皮能力无影响,最佳比例4∶2。结论:丁香罗勒油透皮凝胶可极大地提高丁香罗勒油的药效。  相似文献   
65.
本文对34例囊肿采用囊腔内注射鱼肝油酸钠治疗,4例于2mo内复发而再次注射,0.5yr后随访无一复发。讨论囊肿的各种治疗方法,提出应用鱼肝油酸钠注射法治疗囊肿操作简便,效果满意,患者也乐于接受。  相似文献   
66.
目的 探讨高氧对新生大鼠肺泡Ⅱ型上皮(alveolar epithelial typeⅡ,ATⅡ)细胞钠转运功能的影响.方法 分离提取新生大鼠ATⅡ细胞,随机分成高氧组和对照组,分别在氧浓度为85%和21%的细胞培养箱中原代培养.应用Western blot方法和全细胞膜片钳技术检测高氧暴露后上皮钠通道(epithelial sodium channel,ENaC)蛋白表达变化及高氧对阿米洛利敏感性钠电流的影响.结果 高氧使新生大鼠ATⅡ细胞中β-ENaC和γ-ENaC表达增加[β-ENaC:(1 d:0.43±0.06 vs0.32 ±0.04,P=0.047;2 d:0.73 ±0.06 vs 0.50±0.08,P=0.019;3 d:0.72±0.08 vs 0.52±0.06,P=0.027);γ-ENaC:(1 d:0.64 ±0.05 vs 0.53 ±0.05,P =0.044;2 d:0.76 ±0.03 vs 0.52 ±0.04,P =0.001;3 d:0.77±0.06 vs 0.61 ±0.05,P=0.025)],同时使阿米洛利敏感性钠电流增强(1 d:13.71±2.77 vs 8.92±1.38,P<0.001;2 d:29.12±11.03 vs 10.41±1.80,P<0.001),面对α-ENaC表达表现出一定的抑制作用(1 d:0.31 ±0.05 vs 0.46 ±0.05,P =0.025;2 d:0.30 ±0.01 vs 0.38 ±0.02,P =0.002;3 d:0.37 ±0.06vs 0.37 ±0.08,P=0.983).结论 高氧促进了 ATⅡ细胞ENaC钠转运功能,ENaC功能障碍并非高氧暴露后肺水肿发生的主要原因.  相似文献   
67.
目的综述聚乙二醇1000维生素E琥珀酸酯(D-α-tocopherol polyethylene glycol 1000 succi-nate,TPGS)在各种纳米制剂中的最新进展。方法查阅国内外相关文献共48篇,对这些文献进行分析、概括和总结。结果 TPGS能够提高药物包封率和细胞吸收,改善药物释放,提高药物生物利用度,并能协同起抗癌疗效。广泛应用于聚合物纳米粒、聚合物胶束、纳米脂质体、纳米药物等纳米给药系统中。结论 TPGS在纳米制剂中有着良好应用前景。  相似文献   
68.
Delta-atracotoxins (delta-ACTX), isolated from the venom of Australian funnel-web spiders, are responsible for the potentially lethal envenomation syndrome seen following funnel-web spider envenomation. They are 42-residue polypeptides with four disulfides and an "inhibitor cystine-knot" motif with structural but not sequence homology to a variety of other spider and marine snail toxins. Delta-atracotoxins induce spontaneous repetitive firing and prolongation of action potentials resulting in neurotransmitter release from somatic and autonomic nerve endings. This results from a slowing of voltage-gated sodium channel inactivation and a hyperpolarizing shift of the voltage-dependence of activation. This action is due to voltage-dependent binding to neurotoxin receptor site-3 in a similar, but not identical, fashion to scorpion alpha-toxins and sea anemone toxins. Unlike other site-3 neurotoxins, however, delta-ACTX bind with high affinity to both cockroach and mammalian sodium channels but low affinity to locust sodium channels. At present the pharmacophore of delta-ACTX is unknown but is believed to involve a number of basic residues distributed in a topologically similar manner to scorpion alpha-toxins and sea anemone toxins despite distinctly different protein scaffolds. As such, delta-ACTX provide us with specific tools with which to study sodium channel structure and function and determinants for phyla- and tissue-specific actions of neurotoxins interacting with site-3.  相似文献   
69.
70.
An efficient method for the quantitative determination of acetaminophen (AAP) and diclofenac sodium (DS) in commercial suppositories based on partial least squares (PLS) treatment of FT‐Raman spectra is described. The relative standard errors of prediction (RSEP) were calculated for calibration and validation data sets to evaluate the quality of the constructed models. In the case of DS determination, RSEP error values of 1.9 % and 2.3 % for the calibration and validation data sets, respectively, were found. For AAP these errors amounted to 1.6–2.3 % and 1.8–2.8 %, respectively, for the different calibration models. Four commercial preparations containing 5, 12.5, 16.7 and 33.3 % (w/w) AAP and one containing 5 % (w/w) DS were successfully quantified using the developed models. Concentrations derived from the developed models correlated strongly with the declared values and yielded recoveries of 99.4–100.2 % and 99.6 % for AAP and DS, respectively. The proposed procedure can be used as a fast, economic and reliable method for quantification of the active pharmaceutical ingredients in suppositories. Copyright © 2012 John Wiley & Sons, Ltd.  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