全文获取类型
收费全文 | 26603篇 |
免费 | 2451篇 |
国内免费 | 2192篇 |
专业分类
耳鼻咽喉 | 212篇 |
儿科学 | 316篇 |
妇产科学 | 376篇 |
基础医学 | 3313篇 |
口腔科学 | 525篇 |
临床医学 | 3706篇 |
内科学 | 4161篇 |
皮肤病学 | 272篇 |
神经病学 | 1523篇 |
特种医学 | 1045篇 |
外国民族医学 | 14篇 |
外科学 | 2785篇 |
综合类 | 4118篇 |
现状与发展 | 8篇 |
一般理论 | 4篇 |
预防医学 | 1641篇 |
眼科学 | 612篇 |
药学 | 2876篇 |
15篇 | |
中国医学 | 1497篇 |
肿瘤学 | 2227篇 |
出版年
2024年 | 94篇 |
2023年 | 414篇 |
2022年 | 1077篇 |
2021年 | 1363篇 |
2020年 | 1008篇 |
2019年 | 919篇 |
2018年 | 879篇 |
2017年 | 882篇 |
2016年 | 768篇 |
2015年 | 1174篇 |
2014年 | 1561篇 |
2013年 | 1294篇 |
2012年 | 1880篇 |
2011年 | 1958篇 |
2010年 | 1309篇 |
2009年 | 1004篇 |
2008年 | 1407篇 |
2007年 | 1396篇 |
2006年 | 1281篇 |
2005年 | 1409篇 |
2004年 | 941篇 |
2003年 | 927篇 |
2002年 | 742篇 |
2001年 | 607篇 |
2000年 | 656篇 |
1999年 | 673篇 |
1998年 | 463篇 |
1997年 | 433篇 |
1996年 | 359篇 |
1995年 | 352篇 |
1994年 | 311篇 |
1993年 | 209篇 |
1992年 | 221篇 |
1991年 | 180篇 |
1990年 | 162篇 |
1989年 | 133篇 |
1988年 | 125篇 |
1987年 | 93篇 |
1986年 | 92篇 |
1985年 | 66篇 |
1984年 | 43篇 |
1983年 | 39篇 |
1982年 | 23篇 |
1981年 | 22篇 |
1980年 | 15篇 |
1979年 | 17篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1965年 | 12篇 |
1959年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
目的 观察语前聋患儿植入诺尔康-晨星人工耳蜗(Nurotron-Venus cochlear implant,Nurotron-Venus CI)后的听觉言语发育情况及其安全性和稳定性.方法 回顾性分析郑州大学第一附属医院行Nurotron-Venus CI植入的78例语前聋患儿的临床资料,患儿植入年龄为13~96月,按植入年龄将患儿分为 A组(13~24月,16 例)、B 组(25~36月,13 例)、C组(37~48月,16 例)、D 组(49~72月,18 例)、 E 组(73~96月,15 例);在患儿术前及开机后1、3、6、12个月采用有意义听觉整合量表(meaningful auditory integration scale,MAIS)(C、D、E组)、婴幼儿有意义听觉整合量表(infant-toddler meaningful auditory integration scale,IT-MAIS )(A、B组)进行听觉能力评估,开机后1、3、6、12个月使用有意义言语使用量表(meaningful use of speech scale,MUSS)进行言语能力评估.术后行X线耳蜗平片检查明确电极位置及形态,定期随访了解术后相关并发症及佩戴人工耳蜗时间和使用情况.结果 所有患儿术前及开机后1、3、6、12月IT-MAIS或MAIS得分分别为1.67±1.19、6.60±5.12、11.86±5.44、17.41±5.04、22.87±5.46分,术后1、3、6、12月MUSS得分分别为5.01±3.26、8.38±3.58、11.88±3.88、16.58±4.95分,随着植入时间延长得分不断上升(均P<0.05);不同年龄组IT-MAIS或MAIS得分比较:术前A组低于C、D、E组,开机后1、3月A、B组低于E组,开机后6月A组低于C、D、E组,B组低于E组(均为P<0.05);不同年龄组MUSS得分比较:开机后1月B组低于E组,开机后3月A、B、C组低于E组,开机后6月A组低于C、D、E组,B组低于E组,开机后1年A组低于C、D、E组(均为P<0.05).所有患儿在开机后1、3、6、12月MUSS与IT-MAIS或MAIS得分相关系数分别为0.918、0.808、0.881、0.756(均为P<0.05),两者呈正相关.78例患儿术后耳蜗位X线平片均显示电极位置正常,形态良好;2例患儿出现处理器故障,其余CI整体工作状态良好.结论 语前聋患儿国产人工耳蜗植入后1年内,所有患儿的听觉言语能力随时间延长不断提高;小龄组患儿听觉言语得分在术后早期低于大龄患儿;听觉能力在开机后12月时已无差异,但小龄组患儿的言语能力仍低于大龄患儿;听觉整合能力越强,言语使用能力越强;Nurotron-Venus CI安全、效果可靠. 相似文献
102.
103.
Yan Zhang Lu Qiao Wenping Ding Kai Wang Yuqiong Chen Liwei Wang 《CTS Clinical and Translational Science》2022,15(8):1926
Efforts to prolong thoracic paravertebral block (TPVB) analgesia include local anesthetic adjuvants, such as dexamethasone (Dex). Previous studies showed that both perineural (PN) and intravenous (i.v.) routes could prolong analgesia. As PN Dex is an off‐label use, anesthesiologists should be fully informed of the clinical differences, if any, on block duration. This study was designed to evaluate the two administration routes of Dex for duration of analgesia in TPVB. Ninety‐five patients scheduled for Ivor‐Lewis esophagectomy were randomized to receive TPVB (0.5% ropivacaine 15 ml), PN or i.v. Dex 8 mg. The primary end point was the duration of analgesia. The secondary end points included pain scores, analgesic consumption, adverse effects rate, and incidence of chronic pain at 3 months postoperatively. The PN‐Dex group showed better analgesic effects than the i.v.‐Dex group (p < 0.05). Similarly, the visual analogue scale scores in patients at 2, 4, 8, and 12 h postoperatively were lower in the PN‐Dex group than the i.v.‐Dex group (p < 0.05). The analgesic consumption in both the PN‐Dex and i.v.‐Dex groups was significantly lower than that in the control group (p < 0.05). Regarding the incidence of chronic pain, regardless of route, Dex decreased the incidence of chronic postsurgical pain and neuropathic pain at 3 months after surgery (p < 0.05), but there were no clinical differences between the i.v.‐Dex and PN‐Dex groups. Perineural dexamethasone improved the magnitude and duration of analgesia compared to that of the i.v.‐Dex group in TPVB in Ivor‐Lewis esophagectomy. However, there were no clinically significant differences between the two groups in the incidence of chronic pain. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? Both perineural (PN) and intravenous (i.v.) dexamethasone (Dex) could prolong the duration of a nerve block, but the superiority of either route is still inconclusive. WHAT QUESTION DID THIS STUDY ADDRESS? The study investigated the effects of the two routes of Dex added to ropivacaine on analgesic effects of thoracic paravertebral block in patients undergoing Ivor‐Lewis esophagectomy. WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? These results extend the knowledge of the superior analgesic effect of Dex for the management of perioperative pain in the setting of Ivor‐Lewis Esophagectomy. HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? Because PN Dex is an off‐label use, our study conformed the safety of Dex as PN adjuvants and extended its application field in clinical work. 相似文献
104.
105.
本文利用能表达HuTNFβ的工程菌株(P20KLT)按常规培养及扩增.即采用LB培养液(内含Amp100.μg/ml Tet 5μg/ml);1:40扩增.当A550达0.1时,加入IAA(20μg/ml),当A550为1.0时,中止培养,离心(5000rpm,4℃)收集菌体。在菌体中按1:5加入缓冲液,冰浴中超声破碎,13,000rpm高速离心20分钟, 相似文献
106.
Normalizing GDNF expression in the spinal cord alleviates cutaneous hyperalgesia but not ongoing pain in a rat model of bone cancer pain 下载免费PDF全文
Zhuofeng Ding Wei Xu Jie Zhang Wangyuan Zou Qulian Guo Changsheng Huang Chang Liu Tao Zhong Jun‐Ming Zhang Zongbin Song 《International journal of cancer. Journal international du cancer》2017,140(2):411-422
Bone cancer pain (BCP) is the most common complication in patients with bone cancer. Glial cell line‐derived neurotrophic factor (GDNF) is believed to be involved in chronic pain conditions. In this article, the expression and roles of GDNF were studied in a rat model of BCP induced by tibia injection of Walker 256 rat mammary gland carcinoma cells. Significant mechanical and thermal hyperalgesia and ongoing pain were observed beginning as early as day 5 post injection. The expression level of GDNF protein examined on day 16 after tibia injection was decreased in the L3 dorsal root ganglion (DRG) and lumbar spinal cord, but not in other spinal levels or the anterior cingulate cortex. Phosphorylation of Ret, the receptor for GDNF family ligands, was also decreased. Furthermore, normalizing GDNF expression with lentiviral vector constructs in the spinal cord significantly reduced mechanical and thermal hyperalgesia, spinal glial activation, and pERK induction induced by tibia injection, but did not affect ongoing pain. Together these findings provide new evidence for the use of GDNF as a therapeutic treatment for bone cancer pain states. 相似文献
107.
108.
Cancer stem cells (CSCs) are a relatively rare subpopulation of tumor cell with self-renewal and tumorigenesis capabilities. CSCs are associated with cancer recurrence, progression, and chemoradiotherapy resistance. Establishing a reliable platform for CSC enrichment and study is a prerequisite for understanding the characteristics of CSCs and discovering CSC-related therapeutic strategies. Certain strategies for CSC enrichment have been used in laboratory, particularly fluorescence-activated cell sorting (FACS) and mammosphere culture. However, these methods fail to recapitulate the in vivo chemical and physical conditions in tumors, thus potentially decreasing the malignancy of CSCs in culture and yielding unreliable research results. Accumulating research suggests the promise of a biomaterial-based three-dimensional (3D) strategy for CSC enrichment and study. This strategy has an advantage over conventional methods in simulating the tumor microenvironment, thus providing a more effective and predictive model for CSC laboratory research. In this review, we first briefly discuss the conventional methods for CSC enrichment and study. We then summarize the latest advances and challenges in biomaterial-based 3D CSC platforms. Design strategies for materials, morphology, and chemical and physical cues are highlighted to provide direction for the future construction of platforms for CSC enrichment and study. 相似文献
109.
Five new guaiane-type sesquiterpenoids, hedyosumins A-E (1-5), together with five known ones (6-10), were isolated from the aerial parts of Hedyosmum orientale. Two known sesquiterpenoids, 10alpha-hydroxy-1,5alpha H-guaia-3,7(11)-dien-8alpha,12-olide and 9alpha-hydroxyasterolide, were obtained as natural products for the first time. Their structures were elucidated on the basis of spectroscopic methods. 9alpha-Hydroxyasterolide (7) showed moderate activities against A-549 and HL-60 tumor cell lines with the IC 50 values of 3.1 and 8.8 microM, respectively. 相似文献
110.
Penicillium herquei isolate GA4 was isolated from the infected Conchocelis of Porphyra yezoensis. A large-scale fermentation using yeast extract sucrose medium and repeated chromatography afforded a new symmetrical urea derivative, hualyzin (1). The structure was determined by detailed NMR spectroscopic investigations and MS fragmentation analysis. 相似文献