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   68470篇
  免费   6586篇
  国内免费   2851篇
耳鼻咽喉   751篇
儿科学   1280篇
妇产科学   1125篇
基础医学   7567篇
口腔科学   1263篇
临床医学   7865篇
内科学   10479篇
皮肤病学   1415篇
神经病学   4272篇
特种医学   2098篇
外国民族医学   15篇
外科学   7557篇
综合类   9618篇
现状与发展   20篇
一般理论   45篇
预防医学   5402篇
眼科学   2129篇
药学   6713篇
  69篇
中国医学   3510篇
肿瘤学   4714篇
  2024年   97篇
  2023年   866篇
  2022年   1518篇
  2021年   3124篇
  2020年   2556篇
  2019年   2196篇
  2018年   2456篇
  2017年   2308篇
  2016年   2177篇
  2015年   2891篇
  2014年   3515篇
  2013年   3644篇
  2012年   5530篇
  2011年   5642篇
  2010年   3726篇
  2009年   3137篇
  2008年   4183篇
  2007年   4042篇
  2006年   3736篇
  2005年   3553篇
  2004年   2612篇
  2003年   2338篇
  2002年   1985篇
  2001年   1225篇
  2000年   1166篇
  1999年   1027篇
  1998年   694篇
  1997年   543篇
  1996年   390篇
  1995年   418篇
  1994年   366篇
  1993年   258篇
  1992年   409篇
  1991年   393篇
  1990年   364篇
  1989年   318篇
  1988年   273篇
  1987年   258篇
  1986年   260篇
  1985年   205篇
  1984年   165篇
  1983年   136篇
  1982年   117篇
  1981年   97篇
  1980年   83篇
  1979年   100篇
  1978年   83篇
  1977年   82篇
  1974年   85篇
  1972年   75篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
21.
目的探讨前路椎体次全切除术和后路椎管扩大椎板成形术对脊髓型颈椎病(CSM)合并椎管狭窄症患者术后疗效及颈椎矢状位参数的影响。方法回顾性分析2010年3月—2015年8月收治的147例CSM合并椎管狭窄症患者的临床资料,其中80例行前路椎体次全切除术治疗(A组),67例行后路椎管扩大椎板成形术治疗(B组)。比较2种手术方法治疗前后日本骨科学会(JOA)评分、Cobb角及矢状位垂直距离(SVA)。将2组患者根据T_1倾斜角分别分为高T_1倾斜角(≥25°)亚组和低T_1倾斜角( 25°)亚组,对不同亚组之间的疗效及手术安全性进行比较。结果 2组术后JOA评分和Cobb角均高于术前,差异有统计学意义(P 0.05)。A组术后SVA低于术前,差异有统计学意义(P 0.05),B组术后SVA与术前相比差异无统计学意义(P 0.05)。A组术后JOA评分和Cobb角均高于B组,SVA低于B组,差异均有统计学意义(P 0.05)。A组中,高T_1倾斜角亚组和低T_1倾斜角亚组JOA评分改善效果和后凸畸形发生率比较差异无统计学意义(P 0.05);B组中,低T_1倾斜角亚组JOA评分改善效果和后凸畸形发生率优于高T_1倾斜角亚组,差异均有统计学意义(P 0.05)。结论相较于后路椎管扩大椎板成形术,前路椎体次全切除术治疗CSM合并椎管狭窄症临床疗效更佳,且有助于改善颈椎矢状位平衡;在高T_1倾斜角水平下,应尽可能选择前路椎体次全切除术。  相似文献   
22.
文题释义:肱骨近端骨折:肱骨近端包括肱骨头及大结节、小结节,中老年人骨质疏松及低能量损伤可导致肱骨近端骨折。 同种异体腓骨:取自于人体异体,经过加工处理,去除其免疫原性,保留其骨性结构,可用于移植修复骨缺损,起到支撑作用。 背景:肱骨近端骨折是临床常见骨折,但对肱骨近端内侧柱缺乏支撑的骨折目前仍是治疗难点,并发症常见,失败率较高。 目的:比较解剖锁定钢板联合同种异体腓骨与单纯解剖锁定钢板治疗肱骨近端骨折的疗效。 方法:使用计算机检索PubMed、Embase、Cochrane Library、Google Scholar、中国知网、万方、维普数据库,检索时间均从建库到2020年2月。检索国内外关于对比研究解剖锁定钢板联合同种异体腓骨与单纯解剖锁定钢板治疗肱骨近端骨折疗效的文献。2名研究员根据纳入和排除标准分别独立筛选文献,提取数据,评估文献中的偏倚风险。纳入12篇相关文献使用RevMan 5.2软件将以下指标进行Meta分析,包括影像学数据、功能评分和并发症。结果与结论:①通过文献检索、根据纳入和排除标准,12篇文献纳入研究,其中11篇为回顾性队列研究,1篇为随机对照研究;纳入研究文献质量高,但GRADE证据质量级别较低。②共纳入958例患者,其中解剖锁定钢板联合同种异体腓骨组411例,单纯解剖锁定钢板组547例;③Meta分析结果显示,解剖锁定钢板联合同种异体腓骨组术后1年肱骨头高度差值(MD=-2.40,95%CI:-2.49至-2.31)、颈干角差值(MD= -6.14,95%CI:-6.62至-5.67)、目测类比评分(MD=-0.22,95%CI:-0.35至-0.08)、肩关节功能评分(MD=4.12,95%CI:2.18-6.06),上肢伤残评分(MD=-10.32,95%CI:-13.44至-7.19)、术后2年的目测类比评分(MD=-0.37,95%CI:-0.55至-0.19)、肩关节功能评分(MD=5.07,95%CI:2.86-7.27)、总体并发症(OR=0.31,95%CI:0.20-0.48)及肱骨头螺钉切出(OR=0.25,95%CI:0.11-0.55)均明显优于单纯解剖锁定钢板组(P < 0.05),肱骨头坏死(OR=0.94,95%CI:0.47-1.88),两组间差异无显著性意义(P > 0.05);④因此,较弱的证据提示,肱骨近端解剖锁定钢板联合同种异体腓骨治疗肱骨近端骨折的短期疗效优于解剖锁定钢板,可减少并发症的发生,促进功能恢复。ORCID: 0000-0002-8486-3932(阳运康) 中国组织工程研究杂志出版内容重点:人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程  相似文献   
23.
24.
目的:探讨长链非编码RNA(long-chain noncoding,lncRNA)PCGEM1 对肺癌A549 细胞恶性生物学行为的影响及其作用机制。方法:收集2016 年3 月至2018 年5 月湖北医药学院附属太和医院胸外科接受手术治疗的62 例肺癌(lung cancer,LC)患者癌组织及相应的癌旁组织标本,并用以上组织构建LC组织芯片。用qPCR检测lncRNA PCGEM1 及miR-148a 在LC组织相应的癌旁组织及LC细胞株中的表达。构建lncRNA PCGEM1 沉默细胞系A549-siPCGEM1 和阴性对照A549-NC,并以A549 细胞作为空白对照(Control 组),用MTT和平板克隆实验检测敲减PCGEM1 对A549 细胞增殖能力的影响,Transwell 和划痕实验检测敲减PCGEM1 对A549 细胞侵袭和迁移能力的影响。使用生物信息学网站StarBase 预测可互补结合PCGEM1的miRNA,再根据Targetscan 网站预测相应可靶向结合miRNA的基因;Western blotting 实验检测TGF-β2/Smad2 信号通路蛋白表达情况。结果:在LC组织中PCGEM1 的表达水平高于癌旁组织而miR-148a 的表达量明显低于癌旁组织(均P<0.05),PCGEM1 在5 种LC细胞株中的表达明显高于人肺成纤维细胞HLF-02(均P<0.05),且以A549 细胞中表达最高。敲减PCGEM1 后,与Control 组和A549-NC 组比较,A549-siPCGEM1 组A549 细胞增殖、侵袭和迁移能力显著降低(均P<0.05)。StarBase 和Targetscan 网站预测结果显示,PCGEM1 可与miR-148a 互补结合,miR-148a 与TGF-β2 存在靶向结合位点。与Control 组和A549-NC组比较,A549-siPCGEM1 组中miR-148a 表达明显升高,TGF-β2 及p-Smad2 蛋白的表达明显降低(均P<0.05)。结论:lncRNA PCGEM1在LC组织和细胞株中高表达,高表达的PCGEM1 可通过下调miR-148a 水平强化TGF β2/Smad2 信号通路,从而促进A549 细胞恶性生物学行为的进展。  相似文献   
25.
Lessons Learned
  • The combination of trametinib and sorafenib has an acceptable safety profile, albeit at doses lower than approved for monotherapy.
  • Maximum tolerated dose is trametinib 1.5 mg daily and sorafenib 200 mg twice daily.
  • The limited anticancer activity observed in this unselected patient population does not support further exploration of trametinib plus sorafenib in patients with hepatocellular carcinoma.
BackgroundThe RAS/RAF/MEK/ERK signaling pathway is associated with proliferation and progression of hepatocellular carcinoma (HCC). Preclinical data suggest that paradoxical activation of the MAPK pathway may be one of the resistance mechanisms of sorafenib; therefore, we evaluated trametinib plus sorafenib in HCC.MethodsThis was a phase I study with a 3+3 design in patients with treatment‐naïve advanced HCC. The primary objective was safety and tolerability. The secondary objective was clinical efficacy.ResultsA total of 17 patients were treated with three different doses of trametinib and sorafenib. Two patients experienced dose‐limiting toxicity, including grade 4 hypertension and grade 3 elevation of aspartate aminotransferase (AST)/alanine aminotransferase (ALT)/bilirubin over 7 days. Maximum tolerated dose was trametinib 1.5 mg daily and sorafenib 200 mg twice a day. The most common grade 3/4 treatment‐related adverse events were elevated AST (37%) and hypertension (24%). Among 11 evaluable patients, 7 (63.6%) had stable disease with no objective response. The median progression‐free survival (PFS) and overall survival (OS) were 3.7 and 7.8 months, respectively. Phosphorylated‐ERK was evaluated as a pharmacodynamic marker, and sorafenib plus trametinib inhibited phosphorylated‐ERK up to 98.1% (median: 81.2%) in peripheral blood mononuclear cells.ConclusionTrametinib and sorafenib can be safely administered up to trametinib 1.5 mg daily and sorafenib 200 mg twice a day with limited anticancer activity in advanced HCC.  相似文献   
26.

Background

Laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding all lead to substantial weight loss in obese patients. Long-term weight loss can be highly variable beyond 1-year postsurgery. This study examines and compares the frequency distribution of weight loss and lack of treatment effect rates after laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding.

Methods

A total of 1,331 consecutive patients at a single academic institution were reviewed from a prospectively collected database. Preoperative data collected included demographics, body mass index, and percent excess weight loss. Postoperative BMI and %EWL were collected at 12, 24, and 36 months. Percent excess weight loss was analyzed by the percentiles of excess weight lost, and the distribution of percent excess weight loss was evaluated in 10% increments. Lack of a successful treatment effect was defined as <25% excess weight loss.

Results

Of the 1,331 patients, 72.4% (963) underwent laparoscopic Roux-en-Y gastric bypass, 18.3% (243) laparoscopic sleeve gastrectomy, and 9.4%(125) laparoscopic adjustable gastric banding. Mean percent excess weight loss was greatest for laparoscopic Roux-en-Y gastric bypass, followed by laparoscopic sleeve gastrectomy, and then by laparoscopic adjustable gastric banding at every time point: at 2 years mean percent excess weight loss was 77.9± 24.4 for laparoscopic Roux-en-Y gastric bypass, 50.8 ± 25.8 for laparoscopic sleeve gastrectomy, and 40.8± 25.9 for laparoscopic adjustable gastric banding (P < .0001). The rates of a successful treatment effect s for laparoscopic Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding were 0.9%, 5.2%, and 24.3% at 1 year; 0.3%, 11.1%, and 26.0% at 2 years; and 1.0%, 25.3%, and 30.2% at 3 years. At 1 year, the odds ratio of lack of a successful treatment effect of laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass was 6.305 (2.125–19.08; P?=?.0004), the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic Roux-en-Y gastric bypass was 36.552 (15.64–95.71; P < .0001), and the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic sleeve gastrectomy was 5.791 (2.519–14.599; P < .0001). At 2 years, the odds ratio for laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass increased to 70.7 (9.4–531.7; P < .0001), the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic Roux-en-Y gastric bypass increased to 128.1 (16.8–974.3; P < .0001), and the odds ratio for laparoscopic adjustable gastric banding versus laparoscopic sleeve gastrectomy decreased to 1.8 (0.9–3.6; P?=?.09).

Conclusion

This study emphasizes the existing variability in weight loss across bariatric procedures as well as in the lack of a treatment effect for each procedure. Although laparoscopic adjustable gastric banding has the greatest rate of a lack of a successful treatment effect, the rate remained stable over 3 years postoperatively. Laparoscopic sleeve gastrectomy showed a doubling in the rate of a lack of a successful treatment effect every year reaching 25% at year 3. The rates for lack of a successful treatment effect for laparoscopic Roux-en-Y gastric bypass remained stable at about 1% for the first 3 years postoperatively.  相似文献   
27.
Fraudulent business practices, such as those leading to the Enron scandal and the conviction of Bernard Madoff, evoke a strong sense of public outrage. But fraudulent or dishonest actions are not exclusive to the realm of big corporations or to evil individuals without consciences. Dishonest actions are all too prevalent in everyone’s daily lives, because people are constantly encountering situations in which they can gain advantages by cutting corners. Whether it’s adding a few dollars in value to the stolen items reported on an insurance claim form or dropping outlier data points from a figure to make a paper sound more interesting, dishonesty is part of the human condition. Here, we explore how people rationalize dishonesty, the implications for scientific research, and what can be done to foster a culture of research integrity.  相似文献   
28.
骨碎补是历代临床常用中药,具有疗伤止痛、补肾强骨、消风祛斑等功效。其主要含黄酮、苯丙素、三萜、酚酸及其苷等类化学成分,现代研究表明骨碎补具有抗骨质疏松、促进骨折愈合、促软骨再生、护牙健齿、保护肾功能、抗炎、防治中毒性耳聋、降血脂等多种生物活性,开发前景广阔。本文对近年来骨碎补的化学成分、药理作用及临床应用研究进行综述,以期为骨碎补的进一步深入系统的研究和开发利用提供依据。  相似文献   
29.
30.

Background

The Lancet Commission on Global Surgery highlighted global surgical need but offered little insight into the specific surgical challenges of children in low-resource settings. Efforts to strengthen the quality of global pediatric surgical care have resulted in a proliferation of partnerships between low-and middle-income countries (LMICs) and high-income countries (HICs). Standardized tools able to reliably measure gaps in delivery and quality of care are important aids for these partnerships. We undertook a systematic review (SR) of capacity assessment tools (CATs) focused on needs assessment in pediatric surgery.

Methods

A comprehensive search strategy of multiple electronic databases was conducted per PRISMA guidelines without linguistic or temporal restrictions. CATs were selected according to pre-defined inclusion criteria. Articles were assessed by two independent reviewers. Methodological quality of studies was appraised using the COSMIN checklist with 4-point scale.

Results

The search strategy generated 16,641 original publications, of which three CATs were deemed eligible. Eligible tools were either excessively detailed or oversimplified. None used weighted scores to identify finer granularity between institutions. No CATs comprehensively included measures of resources, outcomes, accessibility/impact and training.

Discussion

The results of this study identify the need for a CAT capable of objectively measuring key aspects of surgical capacity and performance in a weighted tool designed for pediatric surgical centers in LMICs.

Type of Study

Systematic Review.

Level of Evidence

II.  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