全文获取类型
收费全文 | 6035篇 |
免费 | 449篇 |
国内免费 | 90篇 |
专业分类
耳鼻咽喉 | 325篇 |
儿科学 | 75篇 |
妇产科学 | 266篇 |
基础医学 | 410篇 |
口腔科学 | 456篇 |
临床医学 | 904篇 |
内科学 | 430篇 |
皮肤病学 | 82篇 |
神经病学 | 621篇 |
特种医学 | 227篇 |
外国民族医学 | 1篇 |
外科学 | 405篇 |
综合类 | 737篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 764篇 |
眼科学 | 56篇 |
药学 | 496篇 |
16篇 | |
中国医学 | 141篇 |
肿瘤学 | 159篇 |
出版年
2024年 | 14篇 |
2023年 | 104篇 |
2022年 | 198篇 |
2021年 | 257篇 |
2020年 | 276篇 |
2019年 | 295篇 |
2018年 | 261篇 |
2017年 | 242篇 |
2016年 | 271篇 |
2015年 | 232篇 |
2014年 | 391篇 |
2013年 | 516篇 |
2012年 | 367篇 |
2011年 | 393篇 |
2010年 | 327篇 |
2009年 | 282篇 |
2008年 | 296篇 |
2007年 | 256篇 |
2006年 | 256篇 |
2005年 | 182篇 |
2004年 | 144篇 |
2003年 | 139篇 |
2002年 | 120篇 |
2001年 | 69篇 |
2000年 | 67篇 |
1999年 | 70篇 |
1998年 | 53篇 |
1997年 | 49篇 |
1996年 | 52篇 |
1995年 | 46篇 |
1994年 | 38篇 |
1993年 | 24篇 |
1992年 | 25篇 |
1991年 | 18篇 |
1990年 | 22篇 |
1989年 | 15篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 30篇 |
1984年 | 16篇 |
1983年 | 21篇 |
1982年 | 15篇 |
1981年 | 20篇 |
1980年 | 6篇 |
1979年 | 17篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 10篇 |
1974年 | 4篇 |
排序方式: 共有6574条查询结果,搜索用时 22 毫秒
11.
Chengappa KN Tohen M Levine J Jacobs T Thase ME Sanger TM Kupfer DJ 《Bipolar disorders》2000,2(4):332-335
Background: The first episode of an illness may respond differently to any treatment compared to multiple episodes of the same illness. This study details the treatment response of six first-episode manic patients who participated in a previously reported study of 139 subjects comparing olanzapine to placebo in bipolar I mania (Tohen M, Sanger TM, McElroy SL, Tollefson GD, Chengappa KNR, Daniel DG. Olanzapine versus placebo in the treatment of acute mania. Am J Psychiatry 1999; 156: 702–709).
Methods: Six first-episode subjects participated in a 3-week double-blind, random assignment, parallel group, placebo-controlled study of olanzapine for bipolar mania. The Young Mania Rating Scale (Y-MRS), Clinical Global Impression, and Hamilton Depression ratings were administered weekly. Lorazepam as rescue medication was permitted for the first 10 days.
Results: Five subjects were randomized to placebo and one to olanzapine. Two subjects (40%) with psychotic mania (who also had their first-illness episode) were assigned to placebo and responded with greater than 50% reduction in the Y-MRS score and also remitted in 3 weeks. Another placebo-assigned subject had a 46% reduction in the Y-MRS scores, and two placebo-assigned subjects worsened. The olanzapine-assigned subject had a 44% reduction in the Y-MRS score. In contrast, 34 of 69 (48.6%) multiple-episode olanzapine subjects responded and 14 of 61 (23.0%) of placebo-treated subjects did.
Conclusions: This preliminary data set suggest there may be differences in treatment response between first-illness episode versus multi-episode bipolar manic subjects. Larger numbers of subjects with these illness characteristics are needed to either confirm or refute this suggestion. 相似文献
Methods: Six first-episode subjects participated in a 3-week double-blind, random assignment, parallel group, placebo-controlled study of olanzapine for bipolar mania. The Young Mania Rating Scale (Y-MRS), Clinical Global Impression, and Hamilton Depression ratings were administered weekly. Lorazepam as rescue medication was permitted for the first 10 days.
Results: Five subjects were randomized to placebo and one to olanzapine. Two subjects (40%) with psychotic mania (who also had their first-illness episode) were assigned to placebo and responded with greater than 50% reduction in the Y-MRS score and also remitted in 3 weeks. Another placebo-assigned subject had a 46% reduction in the Y-MRS scores, and two placebo-assigned subjects worsened. The olanzapine-assigned subject had a 44% reduction in the Y-MRS score. In contrast, 34 of 69 (48.6%) multiple-episode olanzapine subjects responded and 14 of 61 (23.0%) of placebo-treated subjects did.
Conclusions: This preliminary data set suggest there may be differences in treatment response between first-illness episode versus multi-episode bipolar manic subjects. Larger numbers of subjects with these illness characteristics are needed to either confirm or refute this suggestion. 相似文献
12.
口服或阴道用米索前列醇用于人工流产术前宫口扩张的比较 总被引:2,自引:0,他引:2
目的 :比较在人工流产术前阴道或口服用米索前列醇后宫口扩张的临床效果。方法 :将 16 1例行人工流产术的早孕妇女分成 3组。第 1组 5 3例和第 2组 5 7例于术前 1h分别经阴道用米索前列醇和口服米索前列醇各 4 0 0 μg ,第 3组为对照组5 1例 ,术前不用任何药物。结果 :第 1组和第 2组宫口扩张有效率分别是 92 % (49/ 5 3)和 89% (5 1/5 7) ,明显高于对照组 0 (0 / 5 1,P <0 .0 1) ;前 2组术中无需使用局部麻醉 (0 / 5 3和 0 / 5 7) ,而对照组则有 74 % (38/ 5 1)的病人需加用局部麻醉 (P <0 .0 1) ;前 2组术中出血量为 (7±s 4 )mL和 (7± 3)mL ,也少于对照组 (12± 4 )mL ,差异有非常显著意义 (P <0 .0 1)。阴道用米索前列醇组与口服米索前列醇组相比 ,术中扩宫口作用差异无显著意义 (P >0 .0 5 ) ,但口服用药组不良反应多于阴道用药组。结论 :阴道用米索前列醇组、口服米索前列醇组术中扩宫口作用肯定 ,出血量小、不良反应轻 ,两者疗效相似 相似文献
13.
细辛脑注射液对支气管哮喘患儿呼吸道炎症因子的影响 总被引:8,自引:1,他引:8
目的观察细辛脑对支气管哮喘患儿呼吸道炎症因子的影响。方法共选取60例支气管哮喘患儿,随机分成2组,治疗组予细辛脑注射液0.5 mg/kg,用10%葡萄糖注射液稀释成0.01%的溶液,静脉滴注,2次/d;对照组用氨茶碱针4~6 mg/kg加入5%葡萄糖注射液100 mL静脉滴注,1次/d,两组均用7 d为1个疗程,共观察2个疗程。结果治疗2周后,两组嗜酸性粒细胞与巨噬细胞治疗前后比较均有明显差异(P均<0.05),同时治疗组的淋巴细胞、CD4 T细胞与治疗前比较均有明显差异(P均<0.05),两组嗜酸性粒细胞、巨噬细胞、淋巴细胞、CD4 T细胞比较也均有明显差异(P均<0.05)。治疗后两组肺功能均比治疗前明显改善(P均<0.05),治疗组的肺功能I、L-5与对照组有明显差异(P<0.05)。结论细辛脑注射液对哮喘患儿呼吸道炎症因子的影响优于氨茶碱组。 相似文献
14.
目的 比较IPSe.max CAD高嵌体和纤维桩核冠对邻牙合面缺损上颌第一前磨牙修复后对抗折力的影响。方法 收集2021年9月至2023年7月在郑州大学第一附属医院因正畸而拔除的60颗上颌第一前磨牙,随机将其分为A、B、C 3组(n=20),A组、B组样本牙进行完善的根管治疗后,制备邻牙合面缺损洞型,分别采用不同的修复方法。A组行IPSe.max CAD高嵌体修复;B组行纤维桩核冠修复;C组为对照组,样本牙不作处理。记录各组折断力值、折断模式,并进行比较。结果 A组、B组和C组折裂载荷值分别为(781.25±61.23)N、(712.51±54.36)N和(420.28±41.28)N,3组间比较,差异有统计学意义(F=262.154,P<0.001),A组的折裂荷载值最高;3组折裂模式均以可修复折裂为主,组间比较差异无统计学意义(P>0.05)。结论 邻牙合面缺损上颌第一前磨牙采用IPSe.max CAD高嵌体修复后具有较好的临床效果,抗折力较高,且折裂模式主要为可修复性折裂。 相似文献
15.
上颌第三磨牙对第一磨牙近中移动影响的研究 总被引:1,自引:0,他引:1
目的探讨萌出中的上颌第三磨牙是否会使上颌第一磨牙向近中移动。方法选择18~24岁正畸患者18例,均拔除4颗第一前磨牙矫治,且随机拔除一侧上颌第三磨牙,两侧其余治疗条件保持一致。治疗3个月后观察两侧上颌第一磨牙近中移动量是否存在差异。结果1)拔除上颌第三磨牙的一侧,其上颌第一磨牙在治疗3个月后未发生明显的近中移动;2)未拔除上颌第三磨牙的一侧,其上颌第一磨牙在治疗3个月后的近中移动量为1mm;3)治疗3个月后,未拔除上颌第三磨牙侧的第一磨牙近中移动量大于拔除第三磨牙侧的第一磨牙的近中移动量,其差异有统计学意义(P<0.01)。结论在正畸治疗的初始阶段,若上颌第三磨牙的萌出间隙不足,其萌出会对其近中的上颌第一磨牙产生影响,导致其近中移动而丧失支抗。 相似文献
16.
Petroleum-based oils are widely used as processing aids in rubber composites to improve processability but can adversely affect rubber composite performance and increase carbon footprint. In this research, liquid guayule natural rubber (LGNR), produced from guayule natural rubber, was used as a renewable processing aid to replace naphthenic oil (NO) in Hevea natural rubber, styrene-butadiene rubber (SBR) and guayule natural rubber (GNR) composites. The rheological properties, thermal stability, glass transition temperature, dynamic mechanical properties, aging, and ozone resistance of rubber composites with and without NO or LGNR were compared. Natural and synthetic rubber composites made with LGNR had similar processability to those made with NO, but had improved thermal stability, mechanical properties after aging, and ozone resistance. This was due to the strong LGNR–filler interaction and additional crosslinks formed between LGNR and the rubber matrices. The glass transition temperature of SBR composites was reduced by LGNR because of its increased molecular mobility. Thus, unlike NO, LGNR processing aid can simultaneously improve rubber composite durability, dynamic performance and renewability. The commercialization of LGNR has the potential to open a new sustainable processing-aid market. 相似文献
17.
Nutritional ergogenic aids (NEAs) are substances included within the group of sports supplements. Although they are widely consumed by athletes, evidence-based analysis is required to support training outcomes or competitive performance in specific disciplines. Combat sports have a predominant use of anaerobic metabolism as a source of energy, reaching peak exertion or sustained effort for very short periods of time. In this context, the use of certain NEAs could help athletes to improve their performance in those specific combat skills (i.e., the number of attacks, throws and hits; jump height; and grip strength, among others) as well as in general physical aspects (time to exhaustion [TTE], power, fatigue perception, heart rate, use of anaerobic metabolism, etc.). Medline/PubMed, Scopus and EBSCO were searched from their inception to May 2022 for randomised controlled trials (RCTs). Out of 677 articles found, 55 met the predefined inclusion criteria. Among all the studied NEAs, caffeine (5–10 mg/kg) showed strong evidence for its use in combat sports to enhance the use of glycolytic pathways for energy production during high-intensity actions due to a greater production of and tolerance to blood lactate levels. In this regard, abilities including the number of attacks, reaction time, handgrip strength, power and TTE, among others, were improved. Buffering supplements such as sodium bicarbonate, sodium citrate and beta-alanine may have a promising role in high and intermittent exertion during combat, but more studies are needed in grappling combat sports to confirm their efficacy during sustained isometric exertion. Other NEAs, including creatine, beetroot juice or glycerol, need further investigation to strengthen the evidence for performance enhancement in combat sports. Caffeine is the only NEA that has shown strong evidence for performance enhancement in combat sports. 相似文献
18.
19.
To deeply understand the adsorption process of oxygen on the surface of a plutonium gallium system and to reveal the chemical reaction mechanism at the initial stage of oxidative corrosion on the surface of plutonium gallium alloy at a theoretical level, the adsorption behavior of oxygen molecules on the surface of a plutonium gallium system was investigated by a first-principles approach based on density flooding theory. The results show that the molecular bond length increases and finally breaks when the surface oxygen molecule is adsorbed on the surface of plutonium gallium system and dissociates into two atomic states. The most likely adsorption position of oxygen molecules on the surface of plutonium gallium system is hole-site vertical adsorption with the adsorption energy size of 10.7 eV. The bonding between oxygen atom and surface is mainly due to the overlapping hybridization of Pu-6s, Pu-7s, Pu-6d, Ga-3d and O-2p orbitals. Oxygen molecules mainly interact with the atoms of the first layer on the surface of the plutonium gallium system. The oxygen atoms after stable adsorption are able to diffuse to the subsurface of the plutonium gallium system after overcoming the energy barrier of 16.7 eV and form a stable structure. The research results reveal the initial reaction process and adsorption law of oxygen on the surface of plutonium gallium system from microscopic level, which is helpful to further explore the surface corrosion prevention technology of plutonium gallium system and improve the reliability and safety of plutonium gallium alloy components. 相似文献
20.
de Sanjose S Cortés X Méndez C Puig-Tintore L Torné A Roura E Bosch FX Castellsague X 《European journal of obstetrics, gynecology, and reproductive biology》2008,140(2):234-240