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   6939篇
  免费   606篇
  国内免费   192篇
耳鼻咽喉   104篇
儿科学   224篇
妇产科学   70篇
基础医学   363篇
口腔科学   40篇
临床医学   417篇
内科学   935篇
皮肤病学   37篇
神经病学   491篇
特种医学   181篇
外科学   604篇
综合类   852篇
预防医学   93篇
眼科学   2712篇
药学   280篇
  2篇
中国医学   204篇
肿瘤学   128篇
  2024年   24篇
  2023年   123篇
  2022年   271篇
  2021年   323篇
  2020年   310篇
  2019年   246篇
  2018年   261篇
  2017年   244篇
  2016年   271篇
  2015年   242篇
  2014年   425篇
  2013年   519篇
  2012年   390篇
  2011年   432篇
  2010年   345篇
  2009年   379篇
  2008年   399篇
  2007年   397篇
  2006年   339篇
  2005年   330篇
  2004年   220篇
  2003年   167篇
  2002年   136篇
  2001年   116篇
  2000年   86篇
  1999年   77篇
  1998年   70篇
  1997年   64篇
  1996年   53篇
  1995年   56篇
  1994年   46篇
  1993年   31篇
  1992年   27篇
  1991年   22篇
  1990年   21篇
  1989年   23篇
  1988年   24篇
  1987年   22篇
  1986年   17篇
  1985年   30篇
  1984年   32篇
  1983年   14篇
  1982年   28篇
  1981年   17篇
  1980年   22篇
  1979年   12篇
  1978年   19篇
  1976年   4篇
  1975年   2篇
  1974年   2篇
排序方式: 共有7737条查询结果,搜索用时 31 毫秒
1.
目的 通过分析特发性肺纤维化急性加重期(AE-IPF)患者证候与血清生物标志物的关系,为中医辨证治疗提供参考。方法 采用观察性研究设计,收集2019年3月至2019年11月三个中心的AE-IPF患者76例,其中痰热壅肺证26例、痰浊阻肺证50例,并纳入健康志愿者10例作为对照。采用ELISA测定患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平,分析与中医证候的相关性。结果 AE-IPF患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平均显著高于健康对照组。血清CCL18、HMGB1、KL-6、MMP-7和SP-D水平在痰热壅肺证和痰浊阻肺证患者间无显著性差异(P>0.05),而血清SP-A水平存在显著性差异(P<0.05)。结论 血清SP-A与AE-IPF证候存在一定的相关性,血清SP-A的浓度升高,与痰热壅肺证关系越密切,反之,血清SP-A浓度降低,则与痰浊阻肺证关系越密切。AE-IPF痰热壅肺证患者的预后可能较痰浊阻肺证患者更差。  相似文献   
2.
3.
4.
目的 利用频域光学相干断层扫描深度增强(enhanced depth imaging spectral domain optical coherence tomography,EDI SD-OCT)观察糖尿病黄斑水肿(diabetic macular edema,DME)患者脉络膜厚度(choroidal thickness,CT)的变化及结构特点,探讨DME病变程度与CT的关系。方法 纳入2型糖尿病患者共123例204眼,其中69眼诊断为DME(DME组),135眼无黄斑水肿为对照组。DME眼依据OCT形态学特点进一步分为视网膜弥漫性增厚(diffuse retinal thickness,DRT)型(34眼)、黄斑囊样水肿(cystoid macular edema,CME)型(19眼)和浆液性视网膜脱离(serous retinal detachment,SRD)型(16眼),利用EDI-OCT分别测量黄斑中心凹下CT和以黄斑为中心上、下、鼻、颞500 μm、1000 μm、1500 μm、2000 μm处CT。结果 DME组黄斑中心凹下CT为(326.72±90.15)μm,对照组为(320.17±106.46)μm,两组之间无统计学差异,但黄斑中心凹下CT与视网膜厚度间具有明显正相关关系(r=0.270,P=0.025)。DME亚型CT分别为:DRT型(303.94±81.47)μm、CME型(304.42±73.98)μm和SRD型(401.63±88.80)μm,SRD型CT明显高于其他亚型(P<0.05),此外,SRD型的周边CT同样呈现均匀一致的增厚;鼻侧CT从500 μm至2000 μm呈距离敏感性降低(P<0.05),但SRD型鼻侧CT降低幅度明显变缓(P=0.195)。结论 SRD型黄斑水肿患者CT在中心凹下及周边部均显著增厚,CT与DME病变程度之间有一定相关性。  相似文献   
5.

Background

Since recent reports have shown that (-)-Epigallocatechin-3-gallate (EGCG) could be used for treating proliferative and inflammatory disorders, we explored its use for the management of corneal chemical burns.

Materials and methods

Initially, EGCG was assayed on the rabbit corneal epithelial cell line RCE1(5T5) to establish the best testing conditions, and to avoid unwanted outcomes in the experimental animals. Then, we studied its effects on cell proliferation, cell cycle progression and cell differentiation. Afterwards, we instilled EGCG in experimental grade II corneal alkali burns in mice, three times a day up to 21 days, and evaluated by slit lamp examination and histological sections of corneal epithelial, corneal endothelial and stromal edema, as well as the presence of inflammatory cells and neovascularization.

Results

EGCG reduced cell growth and led to a decline in the proportion of proliferative cells in a concentration dependent manner. At 10 μM, EGCG promoted cell differentiation, an effect not related with apoptosis or cytotoxicity. When 10 μM EGCG was instilled in corneal alkali burns in mice three times a day up to 21 days, EGCG significantly reduced corneal opacity and neovascularization. The improved clinical appearance of the cornea was associated to a controlled epithelial growth; epithelial morphology was similar to that observed in normal epithelium and contrasted with the hyperproliferative, desquamating epithelium observed in control burn wounds. EGCG reduced corneal, stromal and endothelial edema, and wound inflammation.

Conclusion

This work constitutes the first evidence for the use of EGCG in the acute phase of a corneal alkali burn, representing a possible novel alternative to improve patient outcomes as an add-on therapy.  相似文献   
6.
7.
BackgroundDifferent studies have reported the efficacy of percutaneous tibial nerve stimulation (PTNS) and transcutaneous tibial nerve stimulation (TTNS) in treating idiopathic overactive bladder (OAB). However, no study has compared the effectiveness of PTNS and TTNS added to bladder training (BT) in idiopathic OAB.ObjectiveTo compare the efficacy of PTNS and TTNS added to BT in women with idiopathic OAB.MethodsWe randomised 60 women with idiopathic OAB into 3 groups. Group 1 (n = 19) received BT, Group 2 (n = 19) received PTNS in addition to BT, and Group 3 (n = 20) received TTNS in addition to BT. PTNS and TTNS were performed 2 days a week, for 30 min a day, for a total of 12 sessions for 6 weeks. Patients were evaluated by incontinence severity (pad test), a 3-day voiding diary (frequency of voiding, incontinence episodes, nocturia and number of pads used), symptom severity, quality of life, treatment success (positive response rate), treatment satisfaction (Likert scale), discomfort level and preparation time for stimulation (sec).ResultsAt the end of treatment; severity of incontinence, frequency of voiding, incontinence episodes, nocturia, number of pads used, symptom severity and quality of life were significantly improved in Groups 2 and 3 versus Group 1 (P < 0.0167). Treatment success and treatment satisfaction were higher in Groups 2 and 3 than Group 1 (P < 0.001 and P < 0.0167, respectively). Level of discomfort was lower, treatment satisfaction was higher and preparation time for stimulation was shorter in Group 3 than Group 2 (P < 0.05).ConclusionBoth the PTNS plus BT and TTNS plus BT were more effective than BT alone in women with idiopathic OAB. These 2 tibial nerve stimulation methods had similar clinical efficacy but with slight differences: TTNS had shorter preparation time, less discomfort level and higher patient satisfaction than PTNS.  相似文献   
8.
Male infertility accounts for 50% of the causes of infertile couples, being more than 30% of unknown etiology. In these cases, empiric treatment can be an option prior to the application of assisted reproduction techniques. Empiric treatment can be categorized as hormonal, such as gonadotropins, antiestrogens and aromatase inhibitors, and antioxidant, with vitamins, trace elements and carnitine, among others. Although scientifically acceptable evidence is limited due to the absence of large randomized and controlled clinical trials, recent systematic reviews and meta-analyses show that treatment with gonadotropins, antiestrogens and antioxidants increases pregnancy and live birth rates and improves seminal parameters. Empiric medical treatment for idiopathic infertility can be considered in specific cases in order to improve semen quality and spontaneous fertility.  相似文献   
9.
10.
MMP-2、TIMP-2与碱烧伤后角膜新生血管形成的实验研究   总被引:1,自引:1,他引:0  
吴娟  张煦 《陕西医学杂志》2005,34(6):650-651,666
目的:探讨基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-2组织型抑制剂(TIMP-2)在碱烧伤大鼠角膜新生血管(CNV)形成中的表达和意义。方法:采用碱烧伤大鼠角膜建立CNV模型,摘除角膜作病理切片,多形核白细胞(PMN)记数;免疫组化法检测MMP-2、TIMP-2的表达。结果:烧伤后1d角膜缘PMN开始增多,到CNV7d组PMN增加最明显,此后逐渐减少;免疫组化显示:MMP-2在CNV中阳性表达逐渐增加,于7d表达最明显,此后随炎性细胞的减少而减弱,21d后几乎无表达;TIMP-2则于早期变化不明显,7d表达开始升高,14d达高峰。结论:烧伤后CNV形成早期,MMP-2活性增高,继而TIMP-2表达增加,使MMP-2活性受抑,基底膜降解受阻,新生血管延伸停滞;CNV形成中,MMP-2的表达增加,并与角膜的炎性反应程度一致,PMN浸润可能是CNV形成的关键因素。  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