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   16624篇
  免费   1290篇
  国内免费   365篇
耳鼻咽喉   447篇
儿科学   71篇
妇产科学   183篇
基础医学   886篇
口腔科学   1248篇
临床医学   1094篇
内科学   1060篇
皮肤病学   1398篇
神经病学   365篇
特种医学   550篇
外国民族医学   1篇
外科学   3739篇
综合类   2056篇
预防医学   358篇
眼科学   3444篇
药学   775篇
  7篇
中国医学   275篇
肿瘤学   322篇
  2024年   10篇
  2023年   283篇
  2022年   286篇
  2021年   544篇
  2020年   618篇
  2019年   489篇
  2018年   443篇
  2017年   559篇
  2016年   643篇
  2015年   516篇
  2014年   1015篇
  2013年   1112篇
  2012年   867篇
  2011年   993篇
  2010年   848篇
  2009年   867篇
  2008年   831篇
  2007年   817篇
  2006年   755篇
  2005年   669篇
  2004年   619篇
  2003年   521篇
  2002年   432篇
  2001年   448篇
  2000年   353篇
  1999年   271篇
  1998年   243篇
  1997年   205篇
  1996年   188篇
  1995年   205篇
  1994年   205篇
  1993年   189篇
  1992年   165篇
  1991年   155篇
  1990年   127篇
  1989年   113篇
  1988年   101篇
  1987年   106篇
  1986年   87篇
  1985年   106篇
  1984年   89篇
  1983年   60篇
  1982年   45篇
  1981年   36篇
  1980年   26篇
  1979年   7篇
  1978年   9篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的 研究不同浓度细菌脂多糖(Lipopolysaccharides,LPS)对选择性激光熔化技术(Selective laser melting,SLM)制作的钴铬钼合金腐蚀行为的影响。方法 分别以SLM法及铸造法各制作12个钴铬钼合金试件,根据在腐蚀电解液中LPS浓度(0、0.15、15、150 μg/mL)不同分为4组,每组3个试件。采用电化学阻抗谱、动电位极化测试法分析2组合金试件在不同浓度脂多糖(LPS)中的腐蚀行为。结果 在单纯人工唾液中,SLM合金和铸造合金的腐蚀参数无统计学上的差异(P> 0.05)。当LPS浓度为150 μg/mL时,SLM合金和铸造合金的电阻(Rp)均显著下降且自腐蚀电流密度(Icorr)显著增大,但SLM合金的Rp值大于铸造合金且Icorr值较小(P< 0.05)。结论 LPS对SLM法和铸造法制作的钴铬钼合金的腐蚀行为均有不利影响,但对SLM法制作的合金的腐蚀影响小于铸造法制得的合金。  相似文献   
2.
3.
4.
Tsukamurella species are obligate aerobic, gram-positive, weak acid-fast, nonmotile bacilli. They are found in various environments, such as soil, water, sludge, and petroleum reservoir wastewater, and belong to the order Actinomycetales. In 2016, there was a reclassification of species within the genus Tsukamurella, merging the species Tsukamurella tyrosinosolvens (T. tyrosinosolvens) and Tsukamurella carboxydivorans. Tsukamurella species are clinically considered to be a rare opportunistic pathogen, because most reported cases have been related to bacteremia and intravascular prosthetic devices and immunosuppression. To date, it has been isolated only from human specimens, and has always been associated with clinical disease; human infections are very rare. Reported infections have included pneumonia, brain abscesses, catheter-related bloodstream infections, ocular infections, bacteremia, and sepsis presenting with septic pulmonary emboli in patients who are immunocompromised. To date, there is no commercially available test for identification. On the other hand, sequence-based identification, including matrix-assisted laser desorption ionization time-of-flight mass spectrometry, is an alternative method for identifying clinical isolates that are either slow growers or difficult to identify through biochemical profiling. The golden standards for diagnosis and optimal management still remain to be determined. However, newer molecular biological techniques can provide accurate identification, and contribute to the appropriate selection of definitive therapy for infections caused by this organism. Combinations of several antimicrobial agents have been proposed for treatment, though the length of treatment for infections has yet to be determined, and should be individualized according to clinical response. Immunocompromised patients often experience severe cases due to infection, and life-threatening T. tyrosinosolvens events associated with dissemination and/or failure of source control have occurred. Favorable prognoses can be achieved through earlier identification of the cause of infection, as well as successful management, including appropriate antibiotic therapy together with source control. Further analyses of similar cases are required to establish the most adequate diagnostic methods and treatment regimens for infections.  相似文献   
5.
目的探讨超脉冲CO2点阵激光联合胶原贴敷料治疗面部痤疮瘢痕的临床效果。方法选取2020年1月至2021年1月宜阳县人民医院收治的60例面部痤疮瘢痕患者作为研究对象,并按照随机数表法将其随机分为观察组和对照组,每组30例,观察组患者采用超脉冲CO2点阵激光联合胶原贴敷料治疗,对照组患者单纯采用超脉冲CO2点阵激光治疗,对比两组患者面部美观度与皮肤屏障功能变化情况、临床疗效以及不良反应发生情况。结果治疗结束后,观察组患者面部皮肤毛孔值、纹理值以及经皮水分丢失(TEWL)、pH值、皮肤红斑指数均明显低于对照组(t=13.490、8.883、2.204、2.692、5.931,P<0.001、P<0.001、P=0.032、P=0.009、P<0.001),角质层含水量明显高于对照组(t=2.752,P=0.008);观察组患者中痊愈10例、显效12例、有效6例、无效2例,明显优于对照组患者的痊愈6例、显效7例、有效9例、无效8例(Z=-2.285,P=0.022);治疗期间,观察组患者不良反应发生率为6.67%,明显低于对照组患者的不良反应发生率30.00%(χ2=5.455,P=0.020)。结论超脉冲CO2点阵激光联合胶原贴敷料治疗面部痤疮瘢痕,可明显改善面部美观度和皮肤屏障功能,疗效显著,且胶原贴敷料可明显降低CO2点阵激光治疗造成的不良反应发生率。  相似文献   
6.
AIM: To identify the predictive factors and laser photocoagulation associated with the use of silicone oil as endotamponade during primary diabetic vitrectomy. METHODS: The medical and surgical records of 690 patients (798 eyes) who underwent primary diabetic vitrectomy at a tertiary eye hospital in China from January 2018 to December 2018 were reviewed in this retrospective cohort study. The patients’ baseline characteristics and preoperative treatments were recorded. The binary Logistic regression model was used to evaluate the risk factors for the use of silicone oil as endotamponade agent during primary vitrectomy for proliferative diabetic retinopathy (PDR)-related complications. RESULTS: Among 690 patients with mean age of 52.1±10.5y (range: 18-85y), 299/690 (43.3%) were female. The 31.6% of the eyes received preoperative laser treatment, and 72.4% of the eyes received preoperative anti-VEGF adjuvant therapy. Non-clearing vitreous haemorrhage (VH) alone or combined with retinal detachment was the main surgical indication (89.5%) for primary vitrectomy. Silicone oil was used as endotamponade in 313 (39.2%) eyes. Lack of preoperative laser treatment [odds ratio (OR) 0.66, 95% confidence interval (CI): 0.48-0.92; P=0.015] and older age (OR 0.96, 95%CI: 0.95-0.98; P<0.001) were predictors of silicone oil tamponade during primary vitrectomy for PDR. CONCLUSION: The lack of preoperative laser treatment is a significant predictor of silicone oil tamponade during primary vitrectomy for PDR. However, the severity of PDR relevant to silicone oil use should be further evaluated.  相似文献   
7.
8.
PurposeTo evaluate the effectiveness and safety of fluoroscopy-guided percutaneous high ligation (FPHL) combined with fluoroscopy-guided foam sclerotherapy (FGFS) to treat varicose veins of the great saphenous veins (GSVs).Materials and MethodsThis was a retrospective study of 113 patients (mean age, 62.1 ± 10.8 years; 60 men) with varicose veins of the GSVs (133 limbs) that were treated with FPHL combined with FGFS between April 1 and October 31, 2019. Demographic and clinical data were collected from these patients before the FPHL procedure, after which FGFS was performed. The preterminal GSV was ligated percutaneously by a percutaneously-positioned polypropylene ligature under fluoroscopic guidance. The outcome of ligation was confirmed by venography. Then, foam sclerotherapy was performed under fluoroscopy. At 1-year follow-up, GSV occlusion was evaluated by ultrasound. The venous clinical severity scores (VCSSs) were compared between the preoperative and 1-year follow-up periods.ResultsThe technical success rate was 100% (133 limbs). Complete 12-month follow-up was available for 112 limbs (84.2%) and 103 of these limbs (92.0%) remained occluded during this period. The VCSS improved from 4.71 ± 2.15 to 0.74 ± 0.60 (V = 6328, P < .001). During follow-up, there were 16 limbs with thrombophlebitis and 38 limbs with saphenous junction pain; these events were alleviated within 2 weeks of the procedure. There was no deep venous thrombosis or other severe adverse events.ConclusionsFPHL combined with FGFS to treat varicose veins in the GSVs achieved an occlusion rate of 92% and improved the clinical symptoms within 1 year; this minimally-invasive procedure was safe and effective.  相似文献   
9.
10.
目的观察重组人表皮生长因子凝胶联合CO2点阵激光治疗烧伤及创伤后增生性瘢痕的临床效果。 方法选择2020年12月至2021年10月安徽医科大学第一附属医院烧伤与创面修复外科收治的20例增生性瘢痕患者,按照随机数字表法将患者分为联合治疗组及单纯激光治疗组,每组10例。术前均对2组患者术区进行拍照存像、消毒、擦干,局部均匀涂抹5%复方利多卡因乳膏后以无菌薄膜封闭保护60 min,擦去乳膏后再次消毒术区。术中使用CO2点阵激光治疗仪对患者瘢痕部位进行扫描,根据患者增生性瘢痕厚度选定合适的机器参数,维持机器频率300 Hz及密度5%,在20~30 J调整能量参数的大小,时间间隔1 s,保证点阵矩形完全覆盖增生瘢痕,允许2次激光形成的热损伤矩阵之间存在25%面积的重叠。术后即刻冷敷创面60 min,冷敷结束至术后1周,单纯激光治疗组不外用任何药物,联合治疗组术区加用重组人表皮生长因子凝胶外用,3次/d。术后3 d治疗部位不碰水,若出现感染情况,可以加用抗生素软膏,点状损伤创面外痂皮未掉落完全时禁止擦洗创面,禁止直接剥除痂皮,禁止术区涂抹化妆品等,避免接受阳光直射。于第1次激光治疗后2个月进行第2次激光治疗,以2次CO2点阵激光治疗为1个疗程,1个疗程治疗后间隔2个月待术区稳定后行疗效判断,计算2组患者治疗的总有效率;根据温哥华瘢痕量表(VSS)与患者与观察者瘢痕评估量表(POSAS)对患者治疗前、第1次激光治疗后2个月、第2次激光治疗后2个月瘢痕的各项指标进行评分。数据比较采用重复测量方差分析和χ2检验。 结果(1)治疗1个疗程后2个月,单纯激光治疗组与联合治疗组患者治疗的总有效率分别为80%(8/10)、90%(9/10),2组间比较差异无统计学意义(χ2=2.40,P=0.49)。(2)对2组VSS评分的各项指标进行比较,其中疼痛、瘙痒、柔软度及厚度评分的组内及组间各时相点比较,差异均无统计学意义(P>0.05)。治疗前、第1次激光治疗后2个月及第2次激光治疗后2个月,单纯激光治疗组VSS评分中色泽评分分别为(1.9±0.7)、(1.9±0.1)、(1.8±1.0)分,联合治疗组分别为(2.9±0.7)、(2.8±0.6)、(1.9±0.7)分,2组在不同时相点组内比较,差异有统计学意义(F= 26.143,P<0.05);2组组间不同时相点比较,差异有统计学意义(F=6.753,P=0.018)。治疗前、第1次激光治疗后2个月及第2次激光治疗后2个月,单纯激光治疗组VSS评分中血管分布评分分别为(1.8±1.0)、(1.7±0.7)、(1.5±1.0)分,联合治疗组分别为(2.6±0.5)、(2.5±0.5)、(1.7±0.8)分,2组在不同时相点组内比较,差异有统计学意义(F=17.603,P<0.05),2组组间不同时相点比较,差异无统计学意义(F= 2.538,P=0.129)。(3)对2组POSAS评分的各项指标进行比较,其中厚度、粗糙度、柔软度和表面积评分的组内及组间各时相点比较,差异均无统计学意义(P>0.05)。治疗前、第1次激光治疗后2个月及第2次激光治疗后2个月,单纯激光治疗组POSAS评分中色泽评分分别为(4.9±2.6)、(4.1±0.8)、(3.5±2.0)分,联合治疗组分别为(7.6±1.1)、(6.8±1.4)、(5.4±1.8)分,2组在不同时相点组内比较,差异有统计学意义(F= 26.509,P<0.05),2组组间不同时相点比较,差异有统计学意义(F= 8.973,P=0.008)。治疗前、第1次激光治疗后2个月及第2次激光治疗后2个月,单纯激光治疗组POSAS评分中血管分布评分分别为(4.4±2.1)、(3.9±0.9)、(3.5±1.6)分,联合治疗组分别为(6.3±1.1)、(5.7±2.0)、(4.5±1.6)分,2组在不同时相点组内比较,差异有统计学意义(F= 20.118,P<0.05),2组组间不同时相点比较,差异有统计学意义(F= 5.744,P=0.028)。 结论重组人表皮生长因子凝胶联合CO2点阵激光及单独使用CO2点阵激光治疗增生性瘢痕均效果明确,但联合使用重组人表皮生长因子凝胶能有效促进创面愈合、改善瘢痕组织血管分布和减少局部色素沉着。  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