全文获取类型
收费全文 | 42637篇 |
免费 | 2421篇 |
国内免费 | 2188篇 |
专业分类
耳鼻咽喉 | 339篇 |
儿科学 | 271篇 |
妇产科学 | 142篇 |
基础医学 | 1630篇 |
口腔科学 | 895篇 |
临床医学 | 4467篇 |
内科学 | 2765篇 |
皮肤病学 | 874篇 |
神经病学 | 470篇 |
特种医学 | 1098篇 |
外国民族医学 | 28篇 |
外科学 | 2668篇 |
综合类 | 11837篇 |
预防医学 | 2748篇 |
眼科学 | 195篇 |
药学 | 9621篇 |
66篇 | |
中国医学 | 6161篇 |
肿瘤学 | 971篇 |
出版年
2024年 | 342篇 |
2023年 | 1081篇 |
2022年 | 1195篇 |
2021年 | 1350篇 |
2020年 | 1113篇 |
2019年 | 1172篇 |
2018年 | 643篇 |
2017年 | 1168篇 |
2016年 | 1240篇 |
2015年 | 1490篇 |
2014年 | 2056篇 |
2013年 | 2165篇 |
2012年 | 2737篇 |
2011年 | 2777篇 |
2010年 | 2345篇 |
2009年 | 2294篇 |
2008年 | 2873篇 |
2007年 | 2307篇 |
2006年 | 2259篇 |
2005年 | 2358篇 |
2004年 | 1768篇 |
2003年 | 1690篇 |
2002年 | 1312篇 |
2001年 | 1291篇 |
2000年 | 926篇 |
1999年 | 764篇 |
1998年 | 659篇 |
1997年 | 596篇 |
1996年 | 574篇 |
1995年 | 517篇 |
1994年 | 440篇 |
1993年 | 346篇 |
1992年 | 283篇 |
1991年 | 271篇 |
1990年 | 250篇 |
1989年 | 223篇 |
1988年 | 103篇 |
1987年 | 98篇 |
1986年 | 62篇 |
1985年 | 47篇 |
1984年 | 21篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1973年 | 1篇 |
1956年 | 2篇 |
1955年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
在钯催化的Suzuki交叉偶联反应中,以聚环氧乙烷-甲醇为混合溶剂,反应结束后用正庚烷提取,产物进入非极性相,收率〉90%。催化剂留在极性相,可循环使用多次。 相似文献
62.
某些疾病可能引起暂时性抗原减弱,血清抗体下降而导致血型鉴定困难。聚凝胺技术具有敏感性高、反应快速等优点,对ABO血型的鉴定有辅助作用。我们采用聚凝胺法辅助鉴定ABO血型2例,现报告如下。 相似文献
63.
64.
凝血因子制品中Tween-80残留量测定方法的对比分析 总被引:1,自引:0,他引:1
目的探讨测定Tween80残留量的两种比色法(分别是以二氯甲烷和氯仿为有机相)之间的差异性。方法分别考察两种方法的灵敏度和线性以及PEG6000和乙醇对测定结果的干扰。结果以二氯甲烷为有机相的方法具有相对较高的灵敏度和线性。PEG6000和乙醇对两种方法均有干扰,而且PEG6000对以氯仿为有机相的方法的干扰相对更为严重。结论乙醇对两种方法具有相似的干扰。在灵敏度、线性和抗PEG6000干扰方面,以二氯甲烷为有机相的方法相对较好。 相似文献
65.
王建明 《现代中西医结合杂志》2007,16(21):3013-3014
痤疮是青年人群中最常见的一种皮肤病,重度痤疮常因面部出现较多炎性皮疹、囊肿、结节而使容貌受损,极大地影响患者身心健康。本病治疗方法较多,但疗效不满意。2000年以来,笔者应用口服异维A酸联合白花蛇舌草针肌肉注射治疗本病,取得较好效果,现报道如下。 相似文献
66.
67.
BACKGROUND: As a non-invasive technique which can provide comprehensive biological information, 1H-magnetic resonance spectroscopy (1H-MRS) may provide valuable reference data for irreversible recovery or reversible changes in ischemic tissue after stroke.
OBJECTIVE: To monitor and evaluate the effect of the urokinase thrombolytic therapy after experimental acute cerebral ischemia by 1H-MRS technology and investigate its adaptability.
DESIGN: Randomly controlled animal study.
SETTINGS: Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science.
MATERIALS: Eleven healthy adult Sprague-Dawley (SD) rats, weighing 260–300 g and of both genders, were supplied by Experimental Animal Center of Tongji Medical Collage, Huazhong University of Science and Technology [SCXK (e) 2004-007]. 4.7T superconducting nuclear magnetic resonance meter was provided by Brucker Company.
METHODS: The experiment was carried out in Shenzhen Hospital of Peking University and National Key Laboratory of Pattern and Atom & Molecular Physics, Wuhan Physics and Mathematics Institute, Chinese Academy of Science from August 2003 to December 2005. ① The rats were randomly divided into 30-minute self-thrombo-embolism group (n =6) and 60-minute self-thrombo-embolism group (n =5). Six rats in 30-minute self-thrombo-embolism group were occluded with clot embolus for 30 minutes and 5 rats in 60-minute self-thrombo-embolism group were occluded for 60 minutes. 10 000 U/kg urokinase was dissolved in 2 mL saline and the operation lasted for 5 minutes. ② 1H-MRS was performed before thrombolysis and at 3 hours and 24 hours after successful embolization. The metabolic changes of N-acetyl-L-aspartic acid (NAA)/phosphocreatine (PCr) + creatine (Cr), choline phosphate (Cho)/PCr+Cr and lactic acid (Lac)/PCr+Cr in the region of interests were analyzed. ③ The T2W image was conducted 24 hours after the thrombolytic therapy with TR=500 ms and TE=25 ms. ④ The subjects were sacrificed immediately after 1H-MRS and the brain tissues were cut into pieces and stained with HE method; in addition, pathological changes were observed under optic microscope.
MAIN OUTCOME MEASURES: ① Metabolic changes of NAA/PCr+Cr, Cho/PCr+Cr and Lac/PCr+Cr in the region of interests; ② T2W image at 24 hours after the thrombolysis; ③ pathological observation of brain tissue.
RESULTS: Eleven rats were all involved in the final analysis. ① Metabolic changes in the region of interests : In 30-minute self-thrombo-embolism group, the Lac peak emerged immediately after the embolism, but the ischemic zone decreased 3 hours after the thrombolytic therapy (0.252±0.01, 0.603±0.01, P < 0.01). Lac/(PCr+Cr) ratio was 0.290±0.01 at 24 hours after thrombolysis, which was higher than that at 3 hours after thrombolysis (P < 0.01). The NAA/ (PCr+Cr) ratio decreased significantly at 3 hours after the thrombolysis as compared with that before thrombolysis (0.922±0.16, 1.196±0.01, P < 0.05). In 60-minute self-thrombo-embolism group, the Lac/(PCr+Cr) ratio was higher at 3 hours after thrombolysis than that before thrombolysis (0.846±0.12, 0.601±0.11, P < 0.05) and the NAA/(PCr+Cr) decreased at 3 hours after the embolism. Fluctuation of NAA/ (PCr+Cr) ranged from 0.68 to 0.75 before thrombolysis and from 0.71 to 0.75 at 3 hours after thrombolysis. ② T2W image: T2W image showed that 2 subjects in 30-minute self-thrombo-embolism group whose Lac/NAA was higher than 0.7 suffered from intracranial hemorrhage. This meant that the subjects with Lac/NAA > 0.7 were more likely to suffer from intracranial hemorrhage. ③ Histological and morphological examinations: Optic microscope demonstrated that interspace surrounding nerve cells was widened at ischemic center; neurons were swelling; nucleus was stained lightly; pyknosis and mesenchymal edema were mainly observed in lateral cortex of brow and vertex and in lateral part of corpus striatum.
CONCLUSION: ①Compound parameters in ischemic area before thrombolysis should be regarded as an important predicting marker for thrombolytic therapy, effect evaluation and termination. ② 1H-MRS combining with other imaging technique is a detecting way for screening cases who are suitable for thrombolytic therapy. 相似文献
68.
CT导引经皮穿刺注射无水乙醇治疗溶骨性骨转移瘤 总被引:1,自引:1,他引:0
目的探讨CT导引下经皮穿刺注射无水乙醇(CT~PEI)治疗溶骨性骨转移瘤的价值及安全性。方法对17例骨转移瘤患者(25个病灶)采用CT—PEI治疗,使用无水乙醇和超化碘油10:1的混合剂,用CT精确定位、准确穿刺瘤灶并密切监控无水乙醇弥散情况及用量,以减少并发症。对接近椎管及椎间孔的病灶,采用利多卡因实验性治疗以避免严重并发症。术前及术后定期CT检查,3例病人行同位素骨扫描检查,与治疗前检查进行对照研究。对患者随访3~30个月观察其临床疗效。结果所有患者经1次CT—PEI治疗后,疼痛即明显减轻,经2~3次CT-PEI治疗后疼痛完全缓解(CR)16例(24处病灶),疼痛部分缓解(PR)1例。术后随访3个月时,23处病灶内肿瘤组织均发生坏死,被高密度碘油混合液均匀浸润。其中,9处病灶体积缩小。随访3~30个月,除1例因周边出现新的肿瘤浸润灶而再次出现疼痛,其余病例转移瘤处止痛效果无反复。所有病例无严重并发症。结论CT—PEI是一种治疗骨转移瘤有效、微创、安全、简便的方法,使骨转移瘤内肿瘤组织坏死,最大限度的杀灭肿瘤细胞,从而达到满意的止痛效果,明显改善恶性肿瘤溶骨性转移病人的生活质量。 相似文献
69.
70.
目的探讨血肿局部炎症、假膜新血管生成、局部纤溶状况及其在CSDH发生、发展中的作用。进而探讨CSDH的发病机制,并为CSDH的治疗及预防复发提供理论依据。方法以78例CSDH患者作为病例组,20例健康人作为正常对照组。采用ELISA法测定患者血清及血肿液中VEGF及IL-6的含量。比较患者末梢静脉血及血肿液中四种因子的含量变化并与正常对照组比较。结果病例组血肿液FDP、d-dimer检测均为阳性,血液为阴性;正常对照组血液FDP、d-dimer检测均为阴性;病例组血清VEGF含量与正常对照组比较差异无统计学意义。血肿液中VEGF浓度高于血清中。病例组血清IL-6浓度与正常对照组差异无统计学意义,血肿液中IL-6浓度高于血清中。CSDH患者血肿液VEGF、IL-6水平没有相关性。结论CSDH患者血肿液局部纤溶亢进,局部VEGF分泌旺盛,新血管生成活跃,局部炎症活跃,可导致CSDH不断扩大而参与CSDH发病机制。抗炎治疗、抑制VEGF的生理作用、有选择的对病人施行促凝治疗,可成为部分CSDH病人保守治疗及预防复发的有效手段。 相似文献