全文获取类型
收费全文 | 3824篇 |
免费 | 279篇 |
国内免费 | 277篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 24篇 |
妇产科学 | 59篇 |
基础医学 | 510篇 |
口腔科学 | 74篇 |
临床医学 | 488篇 |
内科学 | 699篇 |
皮肤病学 | 16篇 |
神经病学 | 232篇 |
特种医学 | 124篇 |
外国民族医学 | 7篇 |
外科学 | 314篇 |
综合类 | 582篇 |
现状与发展 | 1篇 |
预防医学 | 201篇 |
眼科学 | 99篇 |
药学 | 389篇 |
1篇 | |
中国医学 | 159篇 |
肿瘤学 | 384篇 |
出版年
2024年 | 11篇 |
2023年 | 72篇 |
2022年 | 165篇 |
2021年 | 210篇 |
2020年 | 146篇 |
2019年 | 122篇 |
2018年 | 111篇 |
2017年 | 114篇 |
2016年 | 101篇 |
2015年 | 170篇 |
2014年 | 203篇 |
2013年 | 188篇 |
2012年 | 297篇 |
2011年 | 296篇 |
2010年 | 161篇 |
2009年 | 135篇 |
2008年 | 194篇 |
2007年 | 182篇 |
2006年 | 180篇 |
2005年 | 214篇 |
2004年 | 128篇 |
2003年 | 149篇 |
2002年 | 103篇 |
2001年 | 73篇 |
2000年 | 91篇 |
1999年 | 91篇 |
1998年 | 69篇 |
1997年 | 71篇 |
1996年 | 41篇 |
1995年 | 41篇 |
1994年 | 33篇 |
1993年 | 27篇 |
1992年 | 21篇 |
1991年 | 32篇 |
1990年 | 17篇 |
1989年 | 21篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 10篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1971年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有4380条查询结果,搜索用时 15 毫秒
1.
Depeng Meng Yichen Meng Bingyang Li Guigang Zeng Bin Zhang Chunlin Hou Haodong Lin Yueping Ouyang 《Journal of orthopaedic science》2021,26(3):409-414
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments. 相似文献
2.
Assessment of Myocardial Infarct Size by Three‐Dimensional and Two‐Dimensional Speckle Tracking Echocardiography: A Comparative Study to Single Photon Emission Computed Tomography
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
3.
Yaobin Ouyang Gongmeizi Liu Wenting Xu Zhen Yang Nianshuang Li Chuan Xie Chun Zhou Jiang Chen Yin Zhu Junbo Hong Nonghua Lu 《Oncology Letters》2021,21(2)
Helicobacter pylori (H. pylori) is a main risk factor for gastric cancer (GC). Epithelial-mesenchymal transition (EMT) is involved in the development and progression of H. pylori-associated GC. However, the exact molecular mechanism of this process remains unclear. The AKT/GSK3β signaling pathway has been demonstrated to promote EMT in several types of cancer. The present study investigated whether H. pylori infection induced EMT, and promoted the development and metastasis of cancer in the normal gastric mucosa, and whether this process was dependent on AKT activation. The expression levels of the EMT-associated proteins, including E-cadherin and N-cadherin, were determined in 165 gastric mucosal samples of different disease stages by immunohistochemical analysis. The expression levels of E-cadherin, N-cadherin, AKT, phosphorylated (p-)AKT (Ser473), GSK3β and p-GSK3β (Ser9) were further determined in H. pylori-infected Mongolian gerbil gastric tissues and cells co-cultured with H. pylori by immunohistochemical analysis and western blotting. The results indicated that the expression levels of the epithelial marker E-cadherin were decreased, whereas the expression levels of the mesenchymal marker N-cadherin were increased during gastric carcinogenesis. Their expression levels were associated with H. pylori infection. Furthermore, H. pylori infection resulted in downregulation of E-cadherin expression and upregulation of N-cadherin expression in Mongolian gerbils and GES-1 cells. In addition, an investigation of the associated mechanism of action revealed that p-AKT (Ser473) and p-GSK3β (Ser9) were activated in GES-1 cells following co-culture with H. pylori. Furthermore, following pretreatment of the cells with the AKT inhibitor VIII, the expression levels of E-cadherin, N-cadherin, p-AKT and p-GSK3β did not show significant differences between GES-1 cells that were co-cultured with or without H. pylori. The levels of p-AKT and p-GSK3β were increased in H. pylori-infected Mongolian gerbils. In conclusion, the present study demonstrated that H. pylori infection activated AKT and resulted in the phosphorylation and inactivation of GSK3β, which in turn promoted early stage EMT. These effects were AKT-dependent. This mechanism may serve as a prerequisite for GC development. 相似文献
4.
Han Wang Hui Ding Bo-wen Ouyang Zhenduo Yang Tan Zhong Hongming Fan Xingwu Zhong 《Eye (London, England)》2020,34(12):2328
ObjectivesTo investigate the effect of corneal stromal pocket irrigation after small-incision lenticule extraction (SMILE) on visual acuity, intraocular pressure (IOP), corneal parameters and complications after surgery.MethodsA total of 242 eyes of 121 patients undergoing SMILE were enrolled in this prospective controlled study, and it was designed for one eye to randomly undergo SMILE with balanced salt solution irrigation of the corneal stromal pocket, while the other eye was not. The uncorrected distance visual acuity (UDVA) and slit lamp examination were recorded at 1 hour, 1 day, 1 week, and 1 month. Postoperative corneal density, corneal biomechanical, corneal endothelial cell number, and anterior OCT images were compared at 1 day, 1 week, and 1 month.ResultsCompared with the nonirrigation group, the irrigation group showed significantly higher UDVA at 1 day postoperatively (P < 0.05), but there was no significant difference during the rest of the postoperative period (1 hour, 1 week, and 1 month). In addition, no significant differences were found in IOP, corneal density, corneal biomechanics, corneal endothelial cells, and corneal morphology. No visual decline or severe postoperative complications were found in the patients in this study.ConclusionsInterlamellar irrigation did not affect IOP, corneal parameters, morphology, complications, or UDVA at 1 hour, 1 week, and 1 month after the operation, but it may promote UDVA 1 day after the operation.Subject terms: Refractive errors, Outcomes research, Surgery 相似文献
5.
Fengxiu Ouyang Binyan Wang Lester M. Arguelles Xiping Xu Jianhua Yang Zhiping Li Liuliu Wang Xue Liu Genfu Tang Houxun Xing Craig Langman Xiaobin Wang 《Archives of osteoporosis》2007,2(1-2):29-43
Summary We prospectively examined bone growth patterns in 894 children aged 6–17 years at the baseline visit, with a 6-year follow-up.
Results show bone “tracking” over a six-year interval and sexual dimorphism of bone attained levels and timing of peak bone
growth. Our findings underscore childhood and adolescence as critical periods for building bone and developing gender differences.
Introduction Bone growth patterns were prospectively examined in 894 Chinese children (496 males), aged 6–17 yrs, from a population-based
twin cohort. Whole-body bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) were measured by DEXA at
baseline and a 6-yr follow-up.
Methods Graphic smoothing plots and generalized estimating equations were used to model bone attained levels, growth, and “tracking”.
Results Attained levels of BMC and BA increased curvilinearly with age. Male attained levels were higher than females after age ∼15 yr,
but BMD was lower between 13–17 yrs (Tanner stage I to IV). In both genders, peak BMC and BMD growth lagged ∼2 yrs behind
peak BA growth, which lagged 2 yrs behind peak height growth. Peak bone growth occurred 1–3 yrs later in males. Over the 6-yr
follow-up, all bone measurements “tracked”, but “shifting” across ranks also occurred, and baseline tertile ranking influenced
bone growth. Females with early menarche had higher attained levels than females with late menarche at age 12–13 yrs.
Conclusion Our findings confirm and expand previous studies on peak bone growth conducted in Caucasian cohorts, particularly sexually
dimorphic and maturational effects. The significant “tracking” of bone measurements in this 6-yr follow-up study underscores
the importance that osteoporosis prevention should begin in childhood and adolescence.
Fengxiu Ouyang and Binyan Wang contributed equally to this article.
Source(s) of support: This study is supported in part by grant R01 HD049059, R01 HL0864619 and R01 AR045651 from the National
Institute of Health and by the Food Allergy Project. 相似文献
6.
Contribution of Gender to Pathophysiology and Clinical Presentation of IBS: Should Management Be Different in Women? 总被引:2,自引:0,他引:2
Ann Ouyang M.B.B.S. Helena F. Wrzos M.D. Ph.D. 《The American journal of gastroenterology》2006,101(S3):S602-S609
The irritable bowel syndrome (IBS) is found more commonly in women than men. It is more prevalent in patients with chronic fatigue syndrome, fibromyalgia, and chronic pelvic pain, all syndromes characterized by pain and found predominantly in women. This article reviews evidence for a role of biological sex factors and gender on the pathways mediating visceral pain. The effect of gonadal hormones on gastrointestinal motility and the sensory afferent pathway and central processing of visceral stimuli and the contribution of gender role to the clinical presentation are discussed. Although differences in responses to treatment modalities between genders exist, the approach to IBS patients in both genders is quite similar. Nevertheless, a special attention to gender role and stress-related factors should be addressed. New developments in research, outlined in the paper, might bring more gender-specific treatments in the future. 相似文献
7.
左双腔支气管导管管端位置与吸气峰压变化的关系 总被引:13,自引:3,他引:10
目的 观测无隆突钩双腔支气管导管(DLT)管端位置与吸气峰压(Ppeak)以及肺顺应性环形状改变的关系,探讨用Ppeak和顺应性环的变化评估DLT管端位置的可行性。方法 拟行右侧剖胸手术的成年患者32例,静脉诱导后插入左Mallinckrodt DLT,吸入氧化亚氮和地氟醚维持麻醉。按纤维支气管镜(FOB)确认DLT管端位置和通气方式将观测过程分为四个阶段:第一阶段(S1),管端位置正确的双肺通气;第二阶段(S2),管端位置正确的左侧单肺通气;第三阶段(S3),管端插入左下支气管(置管过深)的左侧单肺通气;第四阶段(S。),管端处在左支气管开口(置管偏浅)的左侧单肺通气。每阶段均机械通气15min。结果 回归方程预计插管深度与FOB检查符合者占71.9%。S2时Ppeak值比S1时增加50.8%,肺顺应性(Cdyn)值减少36.2%;S3时Ppeak值比S1时增加87.4%,Cdyn值减少56.8%。PV环曲线斜率向右明显移位,环体显著延长。结论 用无隆突钩DLT行肺隔离,在无FOB定位的条件时,联合应用听诊法、回归方程预计插管深度、动态监测气道峰压和P-V环的变化综合评估,可提高DLT管端的正确到位率。单肺通气的气道峰压超过双肺通气时的1.65倍,且气道峰压超过25cm H2O.应高度怀疑DLT管端发生过深移位。 相似文献
8.
Agilent 2100 Bioanalyzer在人乳头瘤病毒检测中的应用 总被引:5,自引:1,他引:4
目的:探讨Agilent2100Bioanalyzer芯片分析系统(简称Bioanalyzer)在人乳头瘤病毒(HPV)的PCR检测和分组中的应用。方法:先分别进行通用引物介导PCR(GP-PCR)和型特异性引物介导PCR,扩增HPV高保守区(L1区)的共同序列和各型(包括HPV6,11,16和18型)的特型性序列,然后分别用常规的琼脂糖凝胶电泳技术和Bioanalyzer对PCR产物进行检测,并比较两种检测方法的准确度,重复性和灵敏度。结果:Bioanalyzer在确定片段长度时的准确度和重复性比琼脂糖凝胶电泳高,前者的准确度在95%以上,后者仅为85%,Bioanalyzer的检测灵敏度比琼脂糖凝胶电泳高100倍,结论:Bioanalyzer芯片分析系统结合PCR方法可对HPV进行特异,准确,稳定,灵敏的检测和型别鉴定,具有重要的推广价值。 相似文献
9.
Remote-controlled catheter ablation of accessory pathways: results from the magnetic laboratory. 总被引:7,自引:0,他引:7
Julian Kyoung-Ryul Chun Sabine Ernst Shibu Matthews Boris Schmidt Dietmar Bansch Sigrid Boczor Amaar Ujeyl Matthias Antz Feifan Ouyang Karl-Heinz Kuck 《European heart journal》2007,28(2):190-195
AIMS: This study evaluates feasibility, safety, and efficacy of magnetic remote-controlled accessory pathway (AP) ablation. METHODS AND RESULTS: The novel magnetic navigation system (MNS) (Niobe, Stereotaxis) creates a steerable magnetic field (0.08 T) controlling the distal magnetic tip of an ablation catheter. In conjunction with a catheter advancer system (Cardiodrive, Stereotaxis) remote catheter ablation is enabled. Conventional electrophysiology study identified AP conduction in 59 patients (37 males, 36+/-14 years, 60 APs). First generation 1-magnet tip (1-M) (group I, n=18), second generation bipolar 3-magnet tip (3-M) (group II, n=27), and third generation quadripolar 3-magnet tip catheters (3-M quad.) (group III, n=14) were used for magnetic remote-controlled ablation. Successful AP ablation was achieved in 67% (group I), 85% (group II), and 92% (group III). A significant decrease of median [IQR: Q1-Q3] fluoroscopy time and dosage was observed: 21.2 [12.1-33.8] min, 1110 [395-3234] microGym2 (group I); 6.5 [4.4-15.4] min, 290 [129-489] microGym2 (group II), and 4.9 [3.4-8.0] min, 129 [74-270] microGym2 (group III). Mean procedure time (217+/-67 min; 182+/-68 min, and 172+/-90 min) significantly decreased in group III. Median number [Q1-Q3] of radiofrequency current applications in groups I, II, and III was 4 [2-9], 4 [2-6], and 2 [2-4], respectively. No complications occurred. CONCLUSION: Remote AP ablation is safe and feasible using the novel MNS. Introduction of the 3-magnet quadripolar ablation catheter significantly improved the efficacy of the procedure. 相似文献
10.
Normal bone marrow progenitors and some leukemic cells develop only a limited amount of thermotolerance. Further, once developed, thermotolerance decays at a faster rate than that normally observed in cells of nonhemopoietic origin. Thermotolerance induction and maintenance correlates with reduced levels of expression of various M(r) 70,000 heat shock proteins (HSP-70) mRNAs after heat shock. We have now compared the accumulation of HSP-70 proteins in heat-shocked human leukemic cells KG-1, HL-60, and K562 to that in Ht1080, a colon carcinoma cell line. We have found reduced accumulation of HSP-70 proteins in all leukemic cells. The rate of decay of HSP-70A mRNA, measured following heat shock by using actinomycin D treatment to inhibit further RNA synthesis, was more rapid in KG-1 and HL-60 cells compared to Ht1080 cells. The half-life of HSP-70A mRNA was 2 h in KG-1 and HL-60 cells while in Ht1080 cells it was > 7 h. HSP-70A mRNA is known to decay with a half-life of 2 h in unheated cells; this is increased to > 7 h following heat shock. We therefore postulate that leukemic cells lack the mechanism to stabilize HSP-70A mRNA after heat shock. One postulated mechanism for HSP-70 mRNA decay rate is known to be due to the nucleotide sequences at the 3'-untranslated region. We examined the 3'-untranslated region in leukemic cells. No sequence variations, however, were observed at either the genomic or the complementary DNA levels between leukemic or nonleukemic tumor cells. Heat shock factor activation and binding by gel retardation assays showed that KG-1 and HL-60 cells had a reduced heat shock factor binding to the heat shock element when compared to K562 and Ht1080 cells. Furthermore, HSF-1 mRNA was found to be expressed at relatively lower levels in HL-60 cells when compared to Ht1080 or KG-1 cells. In conclusion, reduced HSP synthesis and accumulation of leukemic cells after heat shock correlates with the reduction in heat shock factor-heat shock element binding and a faster HSP-70A mRNA decay rate that is observed in these cells. 相似文献