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   37949篇
  免费   4348篇
  国内免费   2941篇
耳鼻咽喉   426篇
儿科学   347篇
妇产科学   303篇
基础医学   3701篇
口腔科学   614篇
临床医学   4806篇
内科学   4899篇
皮肤病学   464篇
神经病学   1689篇
特种医学   1647篇
外国民族医学   11篇
外科学   4733篇
综合类   8045篇
现状与发展   14篇
一般理论   2篇
预防医学   2911篇
眼科学   869篇
药学   4255篇
  34篇
中国医学   2673篇
肿瘤学   2795篇
  2024年   181篇
  2023年   776篇
  2022年   1961篇
  2021年   2412篇
  2020年   1902篇
  2019年   1422篇
  2018年   1457篇
  2017年   1439篇
  2016年   1273篇
  2015年   1954篇
  2014年   2316篇
  2013年   2408篇
  2012年   3207篇
  2011年   3480篇
  2010年   2517篇
  2009年   2041篇
  2008年   2241篇
  2007年   2198篇
  2006年   1933篇
  2005年   1782篇
  2004年   1162篇
  2003年   964篇
  2002年   818篇
  2001年   624篇
  2000年   564篇
  1999年   524篇
  1998年   252篇
  1997年   260篇
  1996年   214篇
  1995年   187篇
  1994年   156篇
  1993年   77篇
  1992年   90篇
  1991年   86篇
  1990年   81篇
  1989年   58篇
  1988年   54篇
  1987年   35篇
  1986年   27篇
  1985年   11篇
  1984年   17篇
  1982年   11篇
  1981年   10篇
  1979年   6篇
  1978年   11篇
  1977年   5篇
  1975年   4篇
  1974年   4篇
  1973年   4篇
  1972年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
Objective:To evaluate the feasibility and safety of prenatal diagnosis by traneabdominal chorionic villus sam-pling(TA-CVS)via the guidance of B-mode ultrasound in the first trimester of gestation.To explore the technique of long time culture and chromosome preparation of villi in early pregnancy.To evaluate the feasibility of the above techniques in the application of the prenatal cytogenetic diagnosis.Methods:One hundred and thirty-five singleton pregnancies at risk were referred from January 2001 to Decem-ber 2007.Results:The average maternal age was 35.2 years.TA-CVS was performed in the 10~13th weeks of gestation and the average gestational age was 10.89 weeks.All attempts at sampling were successful.The rate of operation-associated fetal loss was 0.74%.The failure rate of prenatal diagnosis because of inadequate amount of specimen was 0.The average culture time was 5-7 days.The success rate of the cell culture was 98.5%.No maternal con-temination and bacterial contamination happened.Fifteen cases of abnormal karyotype and one case of confined pla-cantel mosaiciem were diagnosed.Conclusion:TA-CVS appears to be safe and feasible and might to be offered in the prenatal diagnosis in the first trimester of gestation.The technique of long time culture and chromosome preparation of villi is stable and reliable.It is feasible to apply these techniques in the clinical practice of prenatal cytogenetic diagnose in the early pregnancy.  相似文献   
132.
血管内机械取栓是治疗大血管闭塞性急性缺血性卒中的有效治疗方法。应结合病史、发
病形式及影像学检查等综合判断病变性质;依据病变性质并参考手术路径,个性化选择支架取栓、
抽吸取栓、球囊/支架血管成形术、动脉溶栓任一种或多种方法联合取栓;并依据手术方式选择手
术材料,以快速高效地完成手术。  相似文献   
133.
钛合金板置入在颅骨缺损修复中的应用   总被引:2,自引:1,他引:1  
目的:探讨钛合金板置入在颅骨缺损修复中的应用。方法:对12例颅骨缺损的患者先进行三维CT检查,设计个性化的钛合金板置入以修复颅骨缺损。结果:本组患者均愈合良好,无感染、钛板外露及头皮血运障碍,避免了再次手术。结论:应用钛合金板修复颅骨缺损,具有良好的生物学力度,抗击性强,并发症少,生物相容性好等优点,可获得较好的治疗效果。  相似文献   
134.
Objective To observe the effect of pulmonary circulation by 6% hydroxyethyl starch 130/0.4 during induction period from epidural block combined with general anesthesia. Methods Twenty-six hepatobiliary surgical patients with ASA Ⅰ-Ⅱ, aged 32 y-59 y, weighing 54 kg-73 kg, were randomized into 2 groups(n=13): hydroxyethyl starch 130/0.4 group(HS)and complex acetic acid Ringer's solution (RL). Above-mentioned solutions were infused 7 ml/kg respectively before induction. The pulmonary circulation hemodynamic parameters such as pulmonary arterial systolic pressure (PASP), pulmonary arterial diastolic pressure (PADP), mean pulmonary artery pressure(MPAP), pulmonary artery wedge pressure(PAWP), pulmonary vascular resistance(PVR) and right ventricular stroke work(RVSW) were recorded at base value(T0), 10 min after infusion(T1), 5 min after induction(T2), 5 rain after intubation(T3), 10 rain after intubation(T4)and 20 min after intubation(T5). Results PASP、PADP、MPAP、PAWP and CVP were significantly higher in group HS at T, than the values at T0 (P<0.05); PVR in group HS was obviously lower from T1 to T5 than the value at To (P<0.05 or P<0.01); RVSW was significantly higher in two groups at T1 than base value (P<0.05), but that in group HS was lower than base value (P<0.05 or P<0.01); HR obviously decreased in two groups from T2 to T5 as compared with the value at T0 (P<0.05); MAP was lower from T3 to T5 than the value at To (P<0.05 or P<0.01). PVR was obviously lower in group HS from T1 to T5 than that in group RL (P<0.05 or P<0.01); MAP obviously increased from T2 to T5 in group HS as compared with the value in group RL(P<0.05 or P<0.01). Conclusion 6% hydroxyethyl starch 130/0.4 can obviously reduce PVR during induction pe-riod from epidural block combined with general anesthesia. In all, there is no effect on pulmonary circulation by 6% hydroxyethyl starch 130/0.4.  相似文献   
135.
腔镜修复术治疗结肠造口旁疝   总被引:2,自引:0,他引:2  
目的总结腔镜下补片修补造口旁疝的手术技术要点。方法回顾性分析2004年9月至2006年11月复旦大学附属华山医院外科收治的16例行腔镜修补术治疗结肠造口旁疝病人的临床资料。结果16例造口旁疝病人中,14例修补成功,2例中转为开放缝合修补(1例因腹腔内广泛致密粘连,1例因小肠损伤)。手术时间平均116min(45~180min)。疝环直径平均5.4cm(4~6cm)。术后出现暂时性腹胀4例,修补区域腹壁疼痛12例(最长持续3周后明显缓解),1例出现呼吸功能减退(经使用无创呼吸机辅助治疗后缓解),7例出现浆液肿(经2~4次穿刺抽液并加压包扎后治愈,无血肿发生,未发生与手术相关的感染)。术后住院时间平均5.4d(3~8d)。术后随访平均7个月(1~17个月),未见早期复发,疝囊较小和发病初期就行修补术者外观优于疝囊较大和发病时间较长者。结论腹腔镜造口旁疝补片修补术从技术上讲是安全、可行的,从早期的临床结果来看,效果亦较理想。  相似文献   
136.
Angiogenesis precedes recovery following spinal cord injury and its extent correlates with neural regeneration, suggesting that angiogenesis may play a role in repair. An important precondition for studying the role of angiogenesis is the ability to induce it in a controlled manner. Previously, we showed that a coculture of endothelial cells (ECs) and neural progenitor cells (NPCs) promoted the formation of stable tubes in vitro and stable, functional vascular networks in vivo in a subcutaneous model. We sought to test whether a similar coculture would lead to the formation of stable functional vessels in the spinal cord following injury. We created microvascular networks in a biodegradable two-component implant system and tested the ability of the coculture or controls (lesion control, implant alone, implant + ECs or implant + NPCs) to promote angiogenesis in a rat hemisection model of spinal cord injury. The coculture implant led to a fourfold increase in functional vessels compared with the lesion control, implant alone or implant + NPCs groups and a twofold increase in functional vessels over the implant + ECs group. Furthermore, half of the vessels in the coculture implant exhibited positive staining for the endothelial barrier antigen, a marker for the formation of the blood–spinal cord barrier. No other groups have shown positive staining for the blood–spinal cord barrier in the injury epicenter. This work provides a novel method to induce angiogenesis following spinal cord injury and a foundation for studying its role in repair.  相似文献   
137.
精液FSH、LH、PRL和T水平与精子质量关系的研究   总被引:3,自引:0,他引:3  
目的探讨人精液中性激素水平与精子质量的关系。方法参照WHO标准方法,进行精子密度、活动率检测,按不同密度和活动率分为4个组。采用ELISA法分析FSH、LH、PRL和T水平。用脱氧核苷酸末端转移酶(TdT)介导的缺口末端标记(TUNEL)法检测生殖细胞的凋亡。结果68例不育者精子密度和活动率随精液性激素水平减少而下降,呈显著性正相关(P均<0.01),生育组精液中FSH、LH、PRL和T水平分别为(1.73±0.15)mIU/ml、(2.28±0.21)mIU/ml、(6.44±0.30)ng/ml、(1.95±0.11)ng/ml,生殖细胞凋亡率为(4.71±1.23)%,与不育组(1.35±0.18)mIU/ml、(1.86±0.32)mIU/ml、(5.96±0.31)ng/ml、(1.55±0.13)ng/ml和(19.36±2.04)%相比有显著性差异(P<0.01)。不育组FSH、LH、PRL、T水平与生殖细胞的凋亡率呈显著性负相关(r分别为-0.89、-0.94、-0.91、-0.98)。结论精液低性激素水平可使睾丸生殖细胞凋亡率增加,精子密度和活率下降而致男性不育。  相似文献   
138.
To explore the electrophysiological proper-ties of differentiation of rat bone marrow-derived stromal stem cells (rBMSCs) to neuron-like cells in vitro by edaravone, a new type of free radical scavenger. Methods: Stromal stem cells were separated from rat bone marrow with Ficoll-Paque reagent and expanded in different culture medium in vitro, rBMSCs were induced by edaravone containing serum-free L-DMEM. Morphologic observation and Western blot analysis including the ex-pression of Nav1.6, Kv1.2, Kv1.3, Cav1.2 were performed, and whole patch-clamp technique was used. Results: Cyton contraction and long processes were shown in differentiated stromal stem cells. Nav1.6, Kv1.2, Kv1.3 and Cav1.2 were expressed in both differentiated and undifferentiated cells. However, the expression of channel proteins in differentiated cells was up-regulated. Consistently, their resting potential and outward currents were also enhanced in the differentiated cells, which was especially significant in the outward rectifier potassium current. Conclusion: In vitro, neuron-like cells derived from rBMSCs, induced by edaravone, possess electrophysiologi-cal properties of neurons.  相似文献   
139.
Pilon骨折的微创治疗   总被引:24,自引:1,他引:23  
目的探讨微创技术治疗Pilon骨折的手术方法、手术指征及其手术疗效。方法采用微创手术治疗的26例Pilon骨折患,平均年龄46.2岁;骨折类型:Rtiedi—Allgower-Pilon骨折分型Ⅰ型12例、Ⅱ型10例、Ⅲ型4例。3例行空心螺钉固定,14例行MIPPO技术钢板固定,9例应用外固定支架,其中4例使用外固定支架结合有限内固定。术后平均随访18.2个月。结果采用Mazur方法评估手术疗效,26例患,优18例、良7例、可1例,优良率92.3%。术后并发症包括创面不愈合1例、复位不良1例、关节退行性变2例。结论正确选择手术时机,术中良好复位,根据骨折类型选择微创固定方式是治疗Pilon骨折有效方法。  相似文献   
140.
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