全文获取类型
收费全文 | 44464篇 |
免费 | 3797篇 |
国内免费 | 3086篇 |
专业分类
耳鼻咽喉 | 354篇 |
儿科学 | 677篇 |
妇产科学 | 628篇 |
基础医学 | 5515篇 |
口腔科学 | 706篇 |
临床医学 | 5906篇 |
内科学 | 7302篇 |
皮肤病学 | 461篇 |
神经病学 | 2774篇 |
特种医学 | 1378篇 |
外国民族医学 | 17篇 |
外科学 | 4882篇 |
综合类 | 6773篇 |
现状与发展 | 5篇 |
一般理论 | 7篇 |
预防医学 | 2681篇 |
眼科学 | 1211篇 |
药学 | 4452篇 |
31篇 | |
中国医学 | 1857篇 |
肿瘤学 | 3730篇 |
出版年
2024年 | 141篇 |
2023年 | 669篇 |
2022年 | 1712篇 |
2021年 | 2190篇 |
2020年 | 1596篇 |
2019年 | 1539篇 |
2018年 | 1598篇 |
2017年 | 1374篇 |
2016年 | 1280篇 |
2015年 | 1917篇 |
2014年 | 2385篇 |
2013年 | 2159篇 |
2012年 | 3221篇 |
2011年 | 3444篇 |
2010年 | 2060篇 |
2009年 | 1687篇 |
2008年 | 2329篇 |
2007年 | 2397篇 |
2006年 | 2230篇 |
2005年 | 2244篇 |
2004年 | 1521篇 |
2003年 | 1476篇 |
2002年 | 1249篇 |
2001年 | 1105篇 |
2000年 | 1126篇 |
1999年 | 1230篇 |
1998年 | 661篇 |
1997年 | 718篇 |
1996年 | 533篇 |
1995年 | 481篇 |
1994年 | 419篇 |
1993年 | 303篇 |
1992年 | 368篇 |
1991年 | 321篇 |
1990年 | 270篇 |
1989年 | 241篇 |
1988年 | 220篇 |
1987年 | 188篇 |
1986年 | 169篇 |
1985年 | 123篇 |
1984年 | 69篇 |
1983年 | 78篇 |
1982年 | 47篇 |
1981年 | 53篇 |
1980年 | 29篇 |
1979年 | 44篇 |
1978年 | 20篇 |
1977年 | 17篇 |
1974年 | 18篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Shan Sun Peng Diao Cuiyun Feng Eleonora-Mihaela Ungureanu Yi Tang Bin Hu Qing Hu 《RSC advances》2018,8(35):19776
Electrochemical oxidative degradation (EOD) is a particularly promising technique for removing organic pollutants from wastewater. However, due to the high overpotential of EOD in conventional anode materials, the energy cost of EOD is usually very high, which greatly promotes the search for highly active, stable, and energy-efficient anodic catalysts. Herein, we demonstrated that nickel-foam-supported (NF-supported) β-Ni(OH)2 (NF/β-Ni(OH)2) prepared via a facile hydrothermal method could be used as an energy efficient anode for EOD. The as-prepared 3D porous NF/β-Ni(OH)2 exhibited high activity toward the electrochemical oxidation of methyl orange (MO) in the low potential region (<1.07 V vs. SCE). This property differs greatly from those of the conventional anode materials that require a high positive potential to keep them active for EOD, making NF/β-Ni(OH)2 an energy-efficient and active anode material for EOD. With an oxidation current density of 0.25 mA cm−2, the decolorization of MO was completed within 30 min, and the COD removal after 3h of reaction was 63.0%. The normalized energy consumption for the 3 h degradation of MO was 22.2 kW h (kg COD)−1, which is only a fraction of (or even one tenth of) the values reported in the literature. Moreover, NF/β-Ni(OH)2 had a good stability and recyclability for EOD. No activity decay was observed during 10 h of EOD and the COD removal remained almost unchanged after four consecutive reaction cycles. We demonstrated experimentally that the NF/β-Ni(OH)2 anode could generate large amounts of hydroxyl radicals and that the oxidation of MO by hydroxyl radicals was the main mechanism during EOD. We believe that this work opens a new avenue for developing highly active and energy-efficient anode materials that can work in the low potential region for EOD.A novel NF/β-Ni(OH)2 catalyst for energy efficient electrochemical degradation of methyl orange was fabricated via a facile hydrothermal method. 相似文献
992.
Xizu Wang Aung Ko Ko Kyaw Cailiu Yin Fei Wang Qiang Zhu Tao Tang Phang In Yee Jianwei Xu 《RSC advances》2018,8(33):18334
Several methods such as the addition of a polar solvent, an acid as well as various post-treatments have been used to improve the thermoelectric performance of conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) films. This paper reports a method using a superacid, trifluoromethanesulfonic acid, in methanol to treat PEDO:PSS films to improve their thermoelectric performance. Treatment of PEDOT:PSS films with this superacid in methanol leads to a significant increase in electrical conductivity from 0.7 to 2980 S cm−1 together with a moderate increase in Seebeck coefficient from 17.6 to 21.9 μV K−1, giving a power factor of 142 μW m−1 K−2, one of the highest values reported in the literature for conductive polymers. The figure of merit (ZT) value is estimated to be 0.19 under optimized conditions. The enhancement of thermoelectric performance, particularly the increase in both electrical conductivity and Seebeck coefficient, is due to the removal of the insulating component and polymer chain realignment giving in turn a denser packing of the conductive PEDOT polymer chains. This post-treatment method would offer an alternative way to improve the thermoelectric performance.Treatment of PEDOT:PSS films with a superacid results in remarkable improvement of thermoelectric performance with a power factor of 142 μW m−1 K−2. 相似文献
993.
Polydopamine is widely used in surface modification, nanofiltration, photonic devices and drug delivery. The formation mechanism and properties of polydopamine are modified by the experimental conditions. Herein we demonstrated a comparison study of free-standing polydopamine films generated at the air–solution interface and their corresponding nanoparticles in solutions, in the presence of various metallic cations, Na+, Ca2+, Mg2+ and Co2+. Adding metallic ions influenced the intermediates in dopamine polymerization, and in turn the morphology and properties of the produced free-standing polydopamine films. Moreover, we observed that the polymerization process accompanying the stratification determines the formation of free-standing films at the air–solution interface: the fast polymerization of dopamine in a Co2+ environment leads to a rugged film surface and porous film body, whereas the comparatively slow polymerization of dopamine under conditions of other metallic ions results in a smooth and solid film. In addition, the water contact angles of the upper and lower surface of the polydopamine films were different. This investigation enriches our knowledge of dopamine polymerization in different environments, which is particularly useful for further application of free-standing polydopamine films.Different stratification processes lead to different morphologies of films generated with various cations. 相似文献
994.
Sai Wang Xuewen Xu Han Luo Chaochao Cao Xiaoyu Song Jianling Zhao Jun Zhang Chengchun Tang 《RSC advances》2018,8(34):19279
SrTiO3/NaTaO3 (STO/NTO) heterojunction photocatalysts were successfully constructed by decorating NaTaO3 nanocubes with SrTiO3 nanoparticles via a hydrothermal method. The structure of the perovskites NaTaO3 and SrTiO3 bear some resemblance to each other, which increases the interface lattice match for promoting the migration of photogenerated carriers between the STO/NTO interfaces. In comparison to pristine NaTaO3 and SrTiO3 samples, the STO/NTO composites exhibited remarkably improved capacity for the degradation of rhodamine B (RhB) under ultraviolet (UV) light (λ < 400 nm) irradiation. Furthermore, the partial replacement of O2− by N3− in the TaO 6 octahedron narrowed the band gap of NaTaO3, which significantly enhanced the photocatalytic performance of the SrTiO3/NaTaO3:N (STO/NTON) heterojunction under visible light (λ > 400 nm). Finally, the possible band structures of the STO/NTO and STO/NTON photocatalysts were proposed, which indicated that an n–n type heterojunction was constructed with a staggered gap for fast separation of photogenerated electron–hole pairs.Novel SrTiO3/NaTaO3 and visible-light-driven SrTiO3/NaTaO3:N nano-heterojunctions with high interface–lattice match were synthesized for efficient photocatalytic removal of organic dye. 相似文献
995.
Jiangying Ru Qiang Wei Lianqing Yang Jing Qin Liangchen Tang Jie Wei Lieping Guo Yunfei Niu 《RSC advances》2018,8(34):18745
Bioactive and degradable scaffolds of nano magnesium silicate (n-MS)/zein (ZN)/poly(caprolactone) (PCL) ternary composites were prepared by 3D-printing method. The results showed that the 3D-printed scaffolds possessed controllable pore structure, and pore morphology, pore size, porosity and pore interconnectivity of the scaffolds can be efficiently adjusted. In addition, the apatite-mineralization ability of the scaffolds in simulated body fluids was obviously improved with the increase of ZN content, in which the scaffold with 20 w% ZN (C20) possessed excellent apatite-mineralization ability. Moreover, the degradability of the scaffolds was significantly enhanced with the increase of ZN content in the scaffolds. The degradation of ZN produced acidic products that could neutralize the alkaline products from the degradation of n-MS, which avoid the increase of pH value in degradable solution. Furthermore, the MC3T3-E1 cells responses (e.g. proliferation and differentiation, etc.) to the scaffolds were significantly promoted with the increase of ZN content. The in vivo osteogenesis of the scaffolds implanted the femur defects of rabbits was investigated by micro-CT and histological analysis. The results demonstrated that the new bone formation was significantly enhanced with the increase of ZN content, in which the C20 scaffold induced the highest new bone tissues, indicating excellent osteogenesis. The results suggested that the ZN in the ternary composite scaffolds played key roles in assisting bone regeneration in vivo.Zein regulating apatite mineralization, degradability, cells responses and osteogenesis of 3D-printed scaffold of n-MS/ZN/PCL ternary composite. 相似文献
996.
唐昱 《中国医院建筑与装备》2015,(2):73-76
文章简要介绍了陕西榆林市第三人民医院项目概况,从院区功能布局、出入口设置、外部空间设计、医疗功能、形体设计等方面详细阐述了规划设计方案,总结和探讨了现代医院整体设计的特点。 相似文献
997.
当建筑师遇到一块山区建筑用地时,往往会醉心于其周围的环境,并乐于迎接其特殊的地形地貌所带来的挑战,但山区用地对于医疗建筑而言并非理想用地,怎样做到医疗功能合理、地尽其用,并做到建筑与环境的自然融合,还原大自然的诊疗效应,是建筑师入手的关键。武当山旅游经济特区医院(以下简称武当山医院)就是众多山地医院中的一个。 相似文献
998.
Wai Kwong Tang Celia J. A. Morgan Grace C. Lau Hua Jun Liang Alan Tang Gabor S. Ungvari 《Substance Abuse》2015,36(1):67-74
Background: No study has examined ketamine users’ psychiatric morbidity using structured diagnostic instruments. The aim of this study was thus to determine the psychiatric comorbidity of community-based ketamine users using the Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), Axis I Disorders (SCID). Methods: A convenience sample of 200 frequent ketamine users was recruited from community organizations in Hong Kong. Participants were screened with the Severity of Dependence Scale (SDS), Beck Depression Inventory (BDI), Anxiety subscale of the Hospital Anxiety Depression Scale (HADSA), and SCID psychotic symptoms. Those who scored above the threshold (cutoff point of 8/9 on the BDI and 4/5 on HADSA) or displayed evidence of psychotic symptoms were referred for a structured clinical interview conducted by a psychiatrist. Results: One hundred and seventy participants scored above the cutoff point on 1 or more of the scales, and 115 participants attended the SCID interview. Fifty-one of these 115 participants received a psychiatric diagnosis of 1 or more comorbidities for the month preceding the interview. Mood disorders accounted for 80.4% of the diagnoses, anxiety disorders for 33.3%, and psychotic disorders for 7.8%. Conclusions: Female gender and history of psychiatric/psychological clinic attendance were significantly associated with comorbid psychiatric disorders, whereas ketamine dependence had a borderline association. 相似文献
999.
目的 建立头孢曲嗪有关物质检查方法.方法 有关物质检查采用Ultimate XB-C18色谱柱(250×4.6mm,5μm),以0.03mol/L的磷酸二氢钾溶液-乙腈(92∶8)为流动相,流速为1.0 mL/min,检测波长为272nm,柱温为35℃,进样体积为20μL.结果 头孢曲嗪与各有关物质分离良好;头孢曲嗪在1.01~808.64μg/mL浓度范围内,峰面积与浓度呈良好的线性关系,相关系数为1.0000,检测限为0.2 ng.丙二醇气相测定法线性良好,加样回收率为115.7%.结论 有关物质检查法快速、专属、准确、可靠,可有效测定目标化合物. 相似文献
1000.
Tang Yundi Sun Xiaotong Wang Yuxuan Luan Huijie Zhang Ruijun Hu Fanlei Sun Xiaolin Li Xia Guo Jianping 《Clinical rheumatology》2021,40(7):2707-2715
Clinical Rheumatology - Interleukin (IL)-24 has been considered as an inflammatory cytokine in autoimmune diseases. However, conflicting data exist and its biological function remains... 相似文献