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   120891篇
  免费   11605篇
  国内免费   8618篇
耳鼻咽喉   1004篇
儿科学   1124篇
妇产科学   1162篇
基础医学   14296篇
口腔科学   1989篇
临床医学   16243篇
内科学   17930篇
皮肤病学   1232篇
神经病学   6446篇
特种医学   4462篇
外国民族医学   78篇
外科学   12361篇
综合类   21018篇
现状与发展   40篇
一般理论   6篇
预防医学   8076篇
眼科学   3415篇
药学   12363篇
  131篇
中国医学   7352篇
肿瘤学   10386篇
  2025年   35篇
  2024年   1743篇
  2023年   2714篇
  2022年   5245篇
  2021年   6540篇
  2020年   5127篇
  2019年   4378篇
  2018年   4213篇
  2017年   3756篇
  2016年   3638篇
  2015年   5465篇
  2014年   6698篇
  2013年   5879篇
  2012年   8536篇
  2011年   9412篇
  2010年   5939篇
  2009年   4689篇
  2008年   6055篇
  2007年   5999篇
  2006年   5799篇
  2005年   5866篇
  2004年   3814篇
  2003年   3495篇
  2002年   3008篇
  2001年   2667篇
  2000年   2809篇
  1999年   2999篇
  1998年   2037篇
  1997年   2049篇
  1996年   1566篇
  1995年   1485篇
  1994年   1284篇
  1993年   806篇
  1992年   988篇
  1991年   796篇
  1990年   673篇
  1989年   635篇
  1988年   531篇
  1987年   468篇
  1986年   411篇
  1985年   313篇
  1984年   141篇
  1983年   121篇
  1982年   78篇
  1981年   79篇
  1980年   56篇
  1979年   54篇
  1978年   9篇
  1977年   7篇
  1976年   4篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Background:Our previous study shows that the empirical formula of Chinese medicine Jianpi-yangwei decoction(JYD)can improve the quality of life in patients with gastric cancer undergoing chemotherapy by increasing beneficial gut bacteria and decreasing harmful bacteria.The present study aims to investigate the effect of JYD on gut fungi in patients with gastric cancer undergoing chemotherapy.Methods:A total of 73 patients with gastric cancer undergoing chemotherapy were recruited.Twenty-nine patients in the chemotherapy group were given standard chemotherapy and 44 patients in the observation group were given JYD plus standard chemotherapy.A control group(55 cases)was recruited from the healthy medical examiners.After 3 months of treatment,life-quality score was evaluated and fecal microbiota was tested by high-throughput sequencing based on the 18S rRNA gene.Results:After treatment,life-quality score in the observation group was significantly lower than that in the chemotherapy group(P<0.05).There was no significant difference between the observation and control groups’diversity and richness indices of intestinal fungi.The Chao index for intestinal fungi in the chemotherapy group was significantly lower than that in the observation group(P<0.05).There was a significant difference between the control and chemotherapy groups in the intestinal fungi according to Shannon and Simpson indices(P<0.05).Linear discriminant analysis effect size analysis showed no significant differences among the three groups,but significant difference in intestinal fungi was observed between the observation group and the chemotherapy group.At the genus level,the relative abundance of the Aspergillus genus in the observation and control groups was significantly lower(P<0.05),the relative abundance of the Cutaneotrichosporon,Galactomyces,and Ganoderma genus taxa was significantly higher compared with those in the chemotherapy group(P<0.05),and there was no significant difference between the observation group and control group.Conclusion:JYD can ameliorate chemotherapy-induced fungal dysbacteriosis in patients with gastric cancer undergoing chemotherapy and improve the quality of life of patients.  相似文献   
92.
徐坚定 《护理研究》2005,19(24):2224-2225
随着磁共振成像技术的不断发展及人们对磁共振增强扫描应用价值水平的提高,使得磁共振增强扫描的应用范围不断扩大和深入.由于它能改变正常组织和病变组织间的信号差别,用于对全身各部位病变和病变内部结构的显示,为进一步定性诊断提供了更多的信息.做好磁共振增强扫描的护理配合,是决定扫描是否成功的关键.现将我室自2003年11月-2004年9月颅脑磁共振增强扫描的护理配合总结如下.……  相似文献   
93.
目的:探讨非医学指征剖宫产儿童在本顿视觉保持测验中的视知觉、视觉记忆、视觉结构能力等认知特征,分析剖宫产对儿童神经心理的影响,为控制人为剖宫产率提供理论支持。方法:于2003-09/10整群选取广州市几所小学三、四年级儿童作为调查对象。共发放自编的“分娩情况和一般家庭情况”调查问卷727份,回收663份,根据回收问卷中分娩方式情况,筛查出非医学指征性剖宫产儿童63例,作为剖宫产组,选择与剖宫产组儿童年龄、性别、学校、班级及家庭一般情况无显著性差异的正常阴道分娩儿童156人作为对照组。应用国内修订版本顿视觉保持测验对两组儿童的视觉记忆保持能力、视觉结构能力和延迟记忆能力进行测试,该测验的测具包括无意义的图卡片C、D、E式各10张,分为4种测验方法,A法、B法为每一图卡片呈现10s或5s后让被试默画,C法为让被试临摹图卡片,D法为每一图卡片呈现10s后间隔15s再让被试默画,本测试采用C式B法,D式C法和E式D法,采用个别施测方式,分别记录两组儿童测验的正确分(每一图卡根据全或无的原则记1或0分,总分范围0~10之间)及错误次数(错误类型分为遗漏、变形、持续、旋转、位置错误和大小错误6个范畴),基本资料进行两组间的成组t检验。结果:所有调查对象全部进入结果分析,无脱落。本顿视觉保持测验结果显示剖宫产儿童在E式D法测验中的得分低于对照组(P<0.05);在D式C法中“位置”错误类型的出现次数多于对照组(P<0.05),在E式D法中“位置”和“变形”错误类型的出现次数较对照组明显偏高(P<0.05)。结论:剖宫产儿童的视觉空间结构能力及视觉延时回忆能力存在缺陷,视空间工作记忆、视觉结构与视觉统和功能不足。  相似文献   
94.
OBJECTIVE: The purpose of this study was to evaluate micro flow imaging (MFI) in depicting the vascular architecture of hepatocellular carcinoma (HCC) and the correlation between pathologic differentiation and the intratumoral vascular architecture pattern. METHODS: Micro flow imaging and contrast harmonic imaging (CHI) were performed in 37 patients with HCC. A sulfur hexafluoride-filled microbubble contrast agent was used. The enhancement level and intratumoral vessels were evaluated on CHI. The vascular architecture of each tumor was evaluated on MFI. Pathologic differentiation of the tumors was classified according to the Edmondson grading system. RESULTS: All 37 HCCs showed hyperenhancement in the arterial phase and hypoenhancement in the portal and late phases on CHI. Intratumoral vessels in the arterial phase were visualized in 20 (54.1%) HCCs. On MFI, the vascular architecture in all lesions was clearly delineated and categorized into 3 patterns: cotton, shrubbery, and deadwood, identified in 12 (32.4%), 22 (59.5%), and 3 (8.1%) of the tumors evaluated, respectively. A chi(2) test showed that pathologic differentiation significantly correlated to the vascular pattern (P = .006). Three (75%) of 4 Edmondson grade I HCCs showed the cotton pattern; 18 (75.0%) of 24 Edmondson grade II HCCs showed the shrubbery pattern; and the deadwood pattern was shown only in Edmondson grade III and IV HCCs. CONCLUSIONS: The MFI technique is more effective in depicting the intratumoral vascular architecture. The vascular architecture pattern correlates with pathologic differentiation of HCC.  相似文献   
95.
96.

Purpose

The correction of severe post-tubercular kyphosis (PTK) is complex and has the disadvantage of being multistaged with a high morbidity. In this study, we evaluated the outcomes of children who underwent single-stage closing–opening wedge osteotomy as a surgical treatment of PTK of the thoracolumbar spine.

Method

Our study group included 12 children with thoracolumbar PTK (seven boys and five girls) with an average age of 9.4 years (range 6–12 years), who were treated at our institution from January 2004 to October 2009. The American Spinal Injury Association Impairment Scale and visual analog scale score were used to classify neurologic function. All patients underwent halo-pelvic traction before surgery and were treated with single-stage closing–opening wedge osteotomy.

Result

The duration of surgery averaged 99 min (range 70–150 min). Average blood loss was 782 ml (range 560–1,200 ml), and the average length of hospital stay was 12 days (range 8–16 days). The neurological function of all patients improved significantly after the procedure. The mean preoperative kyphotic angle was 83.3° (range 59–118°), which had reduced to 27.6° (range 20–38°) at the final follow-up visit. All patients had solid fusion, and no major complications were observed through the final follow-up visit.

Conclusion

Single-stage closing–opening wedge osteotomy is an effective method to correct severe thoracolumbar PTK. A main advantage of the procedure is that it is a posterior-only, single-staged surgery, allowing for significant correction with minimal complications.  相似文献   
97.
98.
MicroRNAs (miRNAs) are small noncoding RNAs that have been critically implicated in several human cancers. miRNAs are thought to participate in various biological processes, including proliferation, cell cycle, apoptosis, and even the regulation of the stemness properties of cancer stem cells. In this study, we explore the potential role of miR-300 in glioma stem-like cells (GSLCs). We isolated GSLCs from glioma biopsy specimens and identified the stemness properties of the cells through neurosphere formation assays, multilineage differentiation ability analysis, and immunofluorescence analysis of glioma stem cell markers. We found that miR-300 is commonly upregulated in glioma tissues, and the expression of miR-300 was higher in GSLCs. The results of functional experiments demonstrated that miR-300 can enhance the self-renewal of GSLCs and reduce differentiation toward both astrocyte and neural fates. In addition, LZTS2 is a direct target of miR-300. In conclusion, our results demonstrate the critical role of miR-300 in GSLCs and its functions in LZTS2 inhibition and describe a new approach for the molecular regulation of tumor stem cells.  相似文献   
99.

Purpose

The use of closed suction drainage systems for hip arthroplasty (HA) is a common practice. However, the effectiveness and safety are still questionable. Thus, the aim of this meta-analysis was to review the advantages and adverse effects of closed suction drainage systems in hip arthroplasty.

Methods

All randomized or quasi-randomized trials comparing the use of closed suction drainage systems with no drainage systems for hip arthroplasty were searched in PubMed, Medicine, EMBASE and other internet databases. We assessed the methodological quality of the studies and abstracted the relevant data independently.

Results

Sixteen studies involving 1,663 participants with surgical wounds comparing HA with and without the use of drainage were included in our analysis. Our results demonstrated blood transfusion was required more frequently the same as the persistent discharge in those who received drains. No significant differences in the incidence of wound hematoma, dehiscence or deep vein thrombosis were found between those allocated to drains and the non-drained wounds. Wound infection and the range of movement of the joint after surgery were similar between the two groups.

Conclusions

Based on the current evidence, there is insufficient evidence to support the routine use of closed suction drainage in hip arthroplasty. At the same time, our meta-analysis study suggested that using of closed suction drainage in HA increased requirement for postoperative blood transfusion. However, there is a moderate possibility of selection bias and publication bias in this review. Because of the limited number of studies which may weaken the strength of the evidence of our results, more samples, high-quality randomized trials are needed to increase the reliability of evidences.

Level of evidence

II.  相似文献   
100.
徐威  常宏  翟允鹏 《消化外科》2014,(8):658-659
1 临床资料 患者女,46岁。因进食后腹胀小适1年余,期间无腹痛、恶心、呕吐、反酸、暖气、呕血、黑便等症状,于当地乡镇卫生院就诊,行上消化道钡餐造影检查,诊断为慢性萎缩性胃炎,给予促胃肠动力、抑酸、保护胃黏膜等保守治疗后症状缓解。此后反复发作腹胀不适,为求进一步诊断与治疗患者于2012年8月28日来我院普通外科就诊。患者自述慢性萎缩性胃炎病史10余年、体格检查:胸部和腹部均无阳性体征。  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