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   21521篇
  免费   1923篇
  国内免费   1477篇
耳鼻咽喉   126篇
儿科学   217篇
妇产科学   197篇
基础医学   2660篇
口腔科学   372篇
临床医学   3050篇
内科学   3122篇
皮肤病学   231篇
神经病学   1129篇
特种医学   730篇
外国民族医学   13篇
外科学   2091篇
综合类   3974篇
现状与发展   5篇
预防医学   1101篇
眼科学   564篇
药学   2308篇
  21篇
中国医学   1195篇
肿瘤学   1815篇
  2024年   78篇
  2023年   415篇
  2022年   970篇
  2021年   1174篇
  2020年   901篇
  2019年   721篇
  2018年   813篇
  2017年   693篇
  2016年   700篇
  2015年   1061篇
  2014年   1276篇
  2013年   1080篇
  2012年   1608篇
  2011年   1769篇
  2010年   1032篇
  2009年   804篇
  2008年   1077篇
  2007年   1042篇
  2006年   1087篇
  2005年   1052篇
  2004年   696篇
  2003年   632篇
  2002年   547篇
  2001年   482篇
  2000年   504篇
  1999年   512篇
  1998年   305篇
  1997年   301篇
  1996年   211篇
  1995年   205篇
  1994年   218篇
  1993年   116篇
  1992年   128篇
  1991年   125篇
  1990年   124篇
  1989年   89篇
  1988年   86篇
  1987年   77篇
  1986年   61篇
  1985年   57篇
  1984年   21篇
  1983年   12篇
  1982年   15篇
  1981年   14篇
  1980年   3篇
  1979年   15篇
  1978年   2篇
  1977年   2篇
  1976年   3篇
  1974年   3篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
李勇  邓高旺  占敏 《江西医药》2009,44(3):197-199
目的探讨胆道探查致十二指肠损伤的诊断和治疗方法。方法回顾性分析我院2005年5月-2008年5月9例胆道探查致十二指肠损伤病案的临床资料。结果3例术中及时发现并行穿孔修补后痊愈出院;6例术中未及时发现而再次手术,其中1例行穿孔修补,4例行穿孔处置管引流+腹腔冲洗+肝下及十二指肠后置双套管持续负压引流+胃肠减压后痊愈出院;1例非手术治疗并发MODS死亡。结论积极预防是重点,术中及时发现和正确处理是关键,并发十二指肠瘘后建立可靠通畅的十二指肠内外引流简单而有效。  相似文献   
102.
A new drug-targeting system for CD13+ tumors has been developed, based on ultrasound-sensitive nanobubbles (NBs) and cell-permeable peptides (CPPs). Here, the CPP-doxorubicin conjugate (CPP-DOX) was entrapped in the asparagine–glycine–arginine (NGR) peptide modified NB (CPP-DOX/NGR-NB) and the penetration of CPP-DOX was temporally masked; local ultrasound stimulation could trigger the CPP-DOX release from NB and activate its penetration. The CPP-DOX/NGR-NBs had particle sizes of about 200?nm and drug entrapment efficiency larger than 90%. In vitro release results showed that over 85% of the encapsulated DOX or CPP-DOX would release from NBs in the presence of ultrasound, while less than 1.5% of that (30?min) without ultrasound. Cell experiments showed the higher cellular CPP-DOX uptake of CPP-DOX/NGR-NB among the various NB formulations in Human fibrosarcoma cells (HT-1080, CD13+). The CPP-DOX/NGR-NB with ultrasound treatment exhibited an increased cytotoxic activity than the one without ultrasound. In nude mice xenograft of HT-1080 cells, CPP-DOX/NGR-NB with ultrasound showed a higher tumor inhibition effect (3.1% of T/C%, day 24), longer median survival time (50 days) and excellent body safety compared with the normal DOX injection group. These results indicate that the constructed vesicle would be a promising drug delivery system for specific cancer treatment.  相似文献   
103.
The possibility of using commercial bayberry tannin (BT) from a Chinese source as a cross-linker and functional additive to develop soybean protein isolate (SPI)-based films was explored in this study by using the solvent casting method. In particular, the impacts of BT loading on the tensile strength, microstructure, thermal stability, water resistance and antioxidant capacity were fully investigated. The results reveal that SPI incorporated with BT yielded a phenolic–protein hybrid whose relevant films exhibited an improvement in tensile strength of around two times greater compared with native SPI as a result of the formed interactions and covalent cross-links, which could be proven using FTIR spectroscopy. The introduction of BT also led to the compact microstructure of SPI–BT films and enhanced the thermal stability, while the water vapor permeability was reduced compared with the control SPI film, especially at high loading content of tannin. Additionally, the use of BT significantly promoted the antioxidant capacity of the SPI-based films according to DPPH radical scavenging assay results. On this basis, Chinese bayberry tannin is considered a promising natural cross-linker and multifunctional additive that can be dedicated to developing protein-derived films with antioxidant activity for food packaging applications.  相似文献   
104.
圆锥角膜的共焦显微镜表现临床分级   总被引:1,自引:2,他引:1  
目的 观察临床上不同阶段圆锥角膜的共焦显微镜图像,推测圆锥角膜的病理发展过程,并进行圆锥角膜的共焦显微镜分级。方法 采用共焦显微镜(Confoscan 2.0),观察24例24眼不同发展阶段(lawless分期)圆锥角膜患者的角膜共焦显微镜图像,进行分析并提出焦显微镜下的临床分分期。结果 共焦显微镜下圆锥角膜首先出现了排列规则的裂隙状暗纹,随着病情的不断进展,病变逐渐由角膜后弹力层向前发展,逐渐累及角膜的后基质和前基质,同时角膜基质细胞核拉长、排列出现紊乱,前后基质细胞失去了原有特征。急性圆锥角膜的患者角膜基质细胞出现水肿,角膜瘢痕在共焦显微镜下呈强反光的无细胞样结构。讨论 共焦显微镜下圆锥角膜的病理发展过程,是从角膜后弹力层开始,由后向前发展,逐渐累及角膜的后基质、前期基质,最后角膜破裂引起急性圆锥角膜,角膜出现水肿,愈合后遗留瘢痕。据此提出圆锥角膜共焦显微镜分期将为四个阶段:第一阶段、角膜裂隙样暗纹累及角膜后弹力层;第二阶段、角膜裂隙样暗纹累及角膜后后基质;第三阶段、角膜裂隙样暗纹累及角膜前基质;第四阶段、出现角膜基质水肿或者瘢痕。  相似文献   
105.
目的 了解鼓室硬化和非鼓室硬化中耳炎患者在抗氧化物质超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalnse,CAT)活性及过氧化反应产物丙二醛(malondialdehyde,MDA)浓度方面的差异,以进一步探讨鼓室硬化形成的机制.方法 回顾分析56例(56耳)中耳炎、中耳炎后遗症手术患者资料,分成两组:鼓室硬化组26耳,非鼓室硬化组30耳.测定所有患者血浆、红细胞中SOD、CAT活力及血浆、中耳组织中MDA浓度.结果 分析用秩和检验及相关分析.结果 两组血浆中MDA含量差异无统计学意义.鼓室硬化组中耳组织中MDA含量较高,差异有统计学意义(P<0.05).两组红细胞中SOD和CAT活力差异无统计学意义.鼓室硬化组血浆中的SOD和CAT活力较非鼓室硬化组低.差异有统计学意义.鼓室硬化组术前的听力平均值与其各检测项目所测得的MDA、SOD、CAT值均不存在相关(P>0.05).结论 鼓室硬化患者可能存在局部氧自由基浓度增高和抗氧化物质活性降低的情况.局部氧自由基浓度增高,血液抗氧化物质无法进入中耳组织,可能是形成鼓室硬化的病理基础.  相似文献   
106.
Objective: The mainstay treatment of esophageal squamous cell carcinoma(ESCC) involves chemotherapy and immunotherapy. However, alternative therapies are required for patients who are refractory or intolerant to existing therapies.Methods: In this single-arm, multicenter, open-label phase Ib study, 30 patients received an intravenous infusion of SCT200, an antiepidermal growth factor receptor(EGFR) monoclonal antibody, 6.0 mg/kg once a week for 6 weeks, followed by 8.0 mg/kg once every 2 weeks u...  相似文献   
107.
The periosteum, a highly vascularized thin tissue, has excellent osteogenic and bone regenerative abilities. The generation of periosteum-mimicking tissue has become a novel strategy for bone defect repair and regeneration, especially in critical-sized bone defects caused by trauma and bone tumor resection. Here, we utilized a bone morphogenetic protein-2(BMP-2)-loaded scaffold to create periosteum-like tissue(PT) in vivo, mimicking the mesenchymal condensation during native long bone developmen...  相似文献   
108.
109.
A systematic examination of the Chinese soft coral Dendronephthya sp. resulted in the isolation and characterization of 18 new cembranoid diterpenes, namely, dendronpholides A-R (2-19), along with 11-episinulariolide and an enantiomer of sandensolide. Their structures were determined through extensive spectroscopic (IR, MS, 2D NMR) data analyses and by comparison with those reported in literature. The cytotoxicity of several compounds against human tumor cell lines was also evaluated.  相似文献   
110.
AIM OF THE STUDY: Our previous results have shown one species of parasitic loranthus (Taxillus chinensis (DC.) Dancer) exhibits potent inhibition on fatty acid synthase (FAS) that is proposed to be a potential therapeutic target for treatment of obesity. However, the medicinal parasitic loranthus come from tens of plants of two families, the Loranthaceae and the Viscaceae. This study was carried out to figure out whether these parasitic loranthus from the two families have similar inhibitory ability on FAS, and whether the parasitic loranthus with potent inhibitory ability on FAS significantly reduce body weight of animal. MATERIALS AND METHODS: CD-1 mice were used to test the effects of samples on their body weight and food intake in 20 days. The reversible and irreversible inhibition on FAS was assayed to study the inhibitory ability of sixteen different medicinal plants from these two families, which were collected in nature. RESULTS: The reversible inhibitory ability of the extracts from the Loranthaceae was nearly 400-fold stronger than that from the Viscaceae. The species from the genus Taxillus Tieghem showed the best effect on FAS in both reversible and irreversible inhibition. Moreover, the difference in host plants did not affect markedly on the inhibitory ability of parasitic loranthus. The medicinal herb with high inhibitory ability on FAS significantly reduced the body weight and food intake of mice by oral administration. CONCLUSIONS: The medicinal herbs from the family Loranthaceae, rather than those from the family Viscaceae, should be suitable to apply as botanical sources of parasitic loranthus for weight control. The herbs from genus Taxillus Tieghem are the best.  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