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   1455篇
  免费   118篇
  国内免费   101篇
耳鼻咽喉   10篇
儿科学   16篇
妇产科学   28篇
基础医学   193篇
口腔科学   18篇
临床医学   199篇
内科学   182篇
皮肤病学   36篇
神经病学   52篇
特种医学   41篇
外国民族医学   1篇
外科学   195篇
综合类   229篇
预防医学   101篇
眼科学   24篇
药学   136篇
  4篇
中国医学   81篇
肿瘤学   128篇
  2024年   1篇
  2023年   19篇
  2022年   47篇
  2021年   79篇
  2020年   67篇
  2019年   56篇
  2018年   70篇
  2017年   57篇
  2016年   61篇
  2015年   71篇
  2014年   71篇
  2013年   76篇
  2012年   128篇
  2011年   122篇
  2010年   92篇
  2009年   49篇
  2008年   78篇
  2007年   66篇
  2006年   47篇
  2005年   60篇
  2004年   32篇
  2003年   41篇
  2002年   37篇
  2001年   25篇
  2000年   27篇
  1999年   36篇
  1998年   20篇
  1997年   25篇
  1996年   23篇
  1995年   10篇
  1994年   9篇
  1993年   11篇
  1992年   14篇
  1991年   9篇
  1990年   10篇
  1989年   4篇
  1988年   5篇
  1987年   5篇
  1986年   7篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
排序方式: 共有1674条查询结果,搜索用时 31 毫秒
41.
目的比较符合米兰标准和符合杭州标准的肝细胞肝癌(HCC)患者行肝移植术后生存和肿瘤复发情况,验证杭州标准的临床应用价值。方法回顾性分析2006年1月至2011年12月中国肝移植注册登记的肝移植手术,并在浙江大学医学院附属第一医院、重庆医科大学附属第一医院两家肝移植中心接受随访调查受者的临床资料,196例肝癌肝移植受者纳入研究。将符合米兰标准的HCC患者作为米兰标准组,共90例(45.9%);超出米兰标准但符合杭州标准者作为杭州标准组,共40例(20.4%);肿瘤结节直径之和8 cm,术前AFP400 ng/m L且组织学分级为低度分化者作为超出杭州标准组,共66例(33.7%)。比较3组受者术后生存率、无瘤生存率,并评判预后。结果米兰标准组受者术后1、3、5年生存率和1、3、5年无瘤生存率分别为88.9%、73.3%、60.0%和84.4%、66.7%、51.1%,杭州标准组受者术后1、3、5年生存率和1、3、5年无瘤生存率分别为80.0%、65.0%、50.0%和75.0%、55.0%、45.0%,超出杭州标准组受者术后1、3、5年生存率和1、3、5年无瘤生存率分别为57.6%、30.3%、18.1%和45.5%、27.3%、18.1%。对3组受者术后累积生存率和无瘤生存率进行比较,米兰标准组和杭州标准组受者术后1、3、5年生存率和1、3、5年无瘤生存率差异均无统计学意义(P均0.05),米兰标准组受者术后1、3、5年生存率和无瘤生存率均显著高于超出杭州标准组受者(P均0.05),杭州标准组受者术后1、3、5年生存率和1、3、5年无瘤生存率均显著高于超出杭州标准组受者(P均0.05)。结论同米兰标准一样,杭州标准也具有很强的科学性,能够显著拓展受益人群,让更多未符合米兰标准的患者能够施行肝移植术。同时杭州标准能有效预测肝移植受者预后,其创新性提出的生物学标准AFP水平和肿瘤分化程度是影响肝癌肝移植受者术后预后的关键性因素。  相似文献   
42.
目的探讨玻璃化冷冻技术在人类卵裂期胚胎冻存中的应用价值。方法回顾性分析本中心261个冷冻胚胎复苏周期,比较2种冷冻方法的胚胎存活率、完好率、妊娠率和种植率等数据。结果玻璃化冷冻组的存活率(97.11%)、完好率(89.02%)和种植率(23.12%)显著高于程序化组(91.31%、63.73%、16.31%)(P<0.05),而妊娠率和平均年龄、平均移植胚胎数、平均内膜厚度两组间无统计学差异(40.26%vs40.22%、31.3±5.3vs32.2±5.5、2.25±0.55vs2.27±0.70、8.9±1.1vs9.1±1.6)(P>0.05)。结论玻璃化冷冻是卵裂期胚胎保存的优选方法。  相似文献   
43.
Background:Decreased platelet (PLT) count is one of the independent risk factors for mortality in intensive care unit (ICU) patients.This study was to investigate the relationship between PLT indices a...  相似文献   
44.
目的分析高危型人乳头瘤病毒(high-risk human papillomavirus,HR-HPV)阴性的不典型鳞状细胞(atypical squamous cells undetermined significance,ASCUS)和低度鳞状上皮内病变(low squamous intraepithelial lesion,LSIL)患者的随访结果,探讨HR-HPV阴性的ASCUS和LSIL患者的合理处理方法。方法回顾性分析2010年1月1日至2012年12月31日期间,就诊于首都医科大学附属北京朝阳医院妇科门诊,HR-HPV阴性、宫颈液基细胞学为ASCUS和LSIL的356例患者的病理资料,对HR-HPV阴性的ASCUS和LSIL经阴道镜及宫颈活检排除高级别病变的306例患者定期进行HR-HPV随访。HR-HPV检测采用杂交检测法2代(hybird capture-Ⅱ,HC-Ⅱ)。结果 HR-HPV阴性/ASCUS和LSIL患者宫颈上皮内瘤变(cervical intraepithelial lesions,CIN)-Ⅲ及以上病变发病率分别为7.9%和9.1%。HR-HPV阳性/ASCUS和LSIL患者CIN-Ⅲ及以上病变发病率分别是22.9%和17.9%。HRHPV阳性的ASCUS和LSIL患者CIN-Ⅲ及以上病变发病率明显高于HR-HPV阴性患者,差异具有统计学意义(P=0.000)。HRHPV阳性对ASCUS及LSIL患者宫颈高级别病变的阴性预测值分别为87.13%和84.42%。HR-HPV阴性/ASCUS和LSIL患者CIN-Ⅱ及以上病变检出率是14.3%。不同年龄段的HR-HPV阴性/ASCUS和LSIL的患者,宫颈高级别病变患者的发生率不同,差异具有统计学意义(P<0.05)。30~39岁妇女宫颈高级别病变的发生率最高(18.2%)。结论 HR-HPV阴性的ASCUS和LSIL患者发生CIN-Ⅲ及以上病变分别是7.9%和9.1%,CIN-Ⅱ及以上病变达14.3%,30~39岁的HR-HPV阴性/ASCUS和LSIL患者宫颈高级别病变发生率达18%,建议对于HR-HPV阴性的ASCUS和LSIL患者应行阴道镜检查可疑病变部位活检。  相似文献   
45.
目的探讨碳酸酐酶IX(carbonic anhydrase-IX,CA-IX)在宫颈脱落细胞中的表达情况及与高危型人乳头瘤病毒(high risk-human papilloma virus,HR-HPV)感染的关系,分析CA-IX预测宫颈病变自然转归方向的价值。方法运用免疫细胞化学技术观察CA-IX在不同宫颈病变宫颈脱落细胞中的表达,采用HC-Ⅱ测定HR-HPV DNA,定期随访,比较CA-IX表达与HR-HPV感染状态的相关性。结果 CA-IX的表达与HPV的感染存在相关性(χ2=81.8,P=0.000)。低级别〔宫颈炎、宫颈上皮内瘤变(cervical intraepithelial neoplasia,CIN-Ⅰ)〕和高级别(CIN-Ⅱ、CIN-Ⅲ及宫颈癌)宫颈病变,CA-IX的阳性表达率差异有统计学意义(χ2=4.5,P=0.032)。不同HPV感染状态下(持续性感染、一过性感染、无HPV感染),CA-IX表达的阳性率分别为60.6%、38.4%、15.6%,差异具有统计学意义(χ2=11.69,P=0.001)。结论 CA-IX的表达与HPV感染相关,在持续性HPV感染中,CA-IX的表达阳性率较一过性HPV感染、无HPV感染明显升高,提示CA-IX有可能是参与持续HPV感染致宫颈上皮内瘤变的分子标志之一。  相似文献   
46.
Bladder cancer (BC) is a lethal cancer that threatens the health of millions of people. Chemotherapy drug resistance, for example, cisplatin (DDP) resistance, is a huge limitation for BC therapy. PTEN pseudogene-1 (PTENP1) has been identified as a significant biomarker of multiple cancers. Therefore, it is essential to illuminate the molecular mechanism of PTENP1 in BC cell DDP resistance and progression. Serum exosomes were isolated using an ExoQuick precipitation kit. Serum exosomes were round-shaped vesicles of 100 ± 60 nm in size. The expression of PTENP1 was down-regulated in serum exosomes isolated from cisplatin non-responsive patients compared with responsive patients. ROC curves certified the diagnostic value of PTENP1. Apparently, PTENP1 transfection inhibited DDP-resistant BC cell proliferation, migration, cisplatin resistance and facilitated apoptosis. Next, we discovered that PTENP1 was a sponge of miR-103a, while PDCD4 was a target of miR-103a. More importantly, PTENP1 regulated DDP-resistant cell viability, migration, apoptosis and cisplatin resistance by interacting with the miR-103a/PDCD4 axis. In addition, PTENP1 hindered tumor growth of cisplatin-resistant mice. Exosome-derived PTENP1 suppressed the DDP resistance of BC by inhibiting cell proliferation, migration and promoting apoptosis through regulating the miR-103a/PDCD4 axis, representing a targeted therapy for DDP-resistant BC patients.

Bladder cancer (BC) is a lethal cancer that threatens the health of millions of people.  相似文献   
47.
目的探讨西安地区部分人群肺功能的特点,生活习惯和环境等因素与肺功能的关系。方法2012年7—8月对西安地区东郊和北郊共405人进行问卷调查和肺功能检测,并用多元逐步回归分析不同因素对肺功能指标的影响。结果西安地区东郊和北郊人群FVC,PEF和FEF25—75均低于正常预计值,东郊和北郊人群之间肺功能主要指标差异有统计学意义(P〈0.001);肺功能主要指标与年龄增长、性别和肺部疾病呈负相关(P〈0.05)。结论西安地区部分人群肺功能主要指标偏低,为今后该地区呼吸系统疾病防治提供依据。  相似文献   
48.
Antigens encoded in the region of difference (RD) of Mycobacterium tuberculosis constitute a potential source of specific immunodiagnostic antigens for distinguishing tuberculosis (TB) infection from BCG vaccination. We evaluated the diagnostic potential of specific T-cell epitopes selected from two immunodominant antigens, Rv1985c and Rv3425, from RD2 and RD11, respectively, on the basis of epitope mapping, in TB patients and BCG-vaccinated healthy individuals. Using a whole-blood gamma interferon release assay, a wide array of epitopes was recognized on both Rv1985c and Rv3425 in TB patients. Those epitopes that could specifically discriminate TB infection from BCG vaccination were carefully selected, and the most promising peptide pools from Rv1985c showed a sensitivity of 53.9% and a specificity of 95.5%. When the novel specific peptides from Rv1985c joined the diagnostic antigens in the QuantiFERON-TB Gold In-Tube (QFT-IT) assay, the sensitivity was increased from 86.4% to 96.2%, with no drop in specificity. These results indicate that the peptide pools selected from Rv1985c and Rv3425 have the potential to diagnose TB infection by a method that may be routinely used in clinical laboratories.  相似文献   
49.
AIM: To evaluate immunological protection of nitric oxide (NO) in hepatopulmonary syndrome and probable mechanisms of ischemia-reperfusion (IR) injury in rat liver transplantation.METHODS: Sixty-six healthy male Wistar rats were randomly divided into three groups (11 donor/recipient pairs). In group II, organ preservation solution was lactated Ringer’s solution with heparin 10  000/μL at 4 °C. In groups I and III, the preservation solution added, respectively, L-arginine or NG-L-arginine methyl ester (L-NAME) (1 mmol/L) based on group II, and recipients were injected with L-arginine or L-NAME (50 mg/kg) in the anhepatic phase. Grafted livers in each group were stored for 6 h and implanted into recipients. Five rats were used for observation of postoperative survival in each group. The other six rats in each group were used to obtain tissue samples, and executed at 3 h and 24 h after transplantation. The levels of alanine aminotransferase (ALT), tumor necrosis factor (TNF)-α and NO metabolites (NOx) were detected, and expression of NO synthase, TNF-α and intercellular adhesion molecule 1 (ICAM-1) was examined by triphosphopyridine nucleotide diaphorase histochemical and immunohistochemical staining.RESULTS: By supplementing L-arginine to strengthen the NO pathway, a high survival rate was achieved and hepatic function was improved. One-week survival rate of grafted liver recipients in group I was significantly increased (28.8 ± 36.6 d vs 4 ± 1.7 d, P < 0.01) as compared with groups II and III. Serum levels of ALT in group I were 2-7 times less than those in groups II and III (P < 0.01). The cyclic guanosine monophosphate (cGMP) levels in liver tissue and NOx in group I were 3-4 times higher than those of group II after 3 h and 24 h reperfusion, while in group III, they were significantly reduced as compared with those in group II (P < 0.01). The levels of TNF-α in group I were significantly lower than in group II after 3 h and 24 h reperfusion (P < 0.01), while being significantly higher in group III than group II (P < 0.01). Histopathology revealed more severe tissue damage in graft liver and lung tissues, and a more severe inflammatory response of the recipient after using NO synthase inhibitor, while the pathological damage to grafted liver and the recipient’s lung tissues was significantly reduced in group I after 3 h and 24 h reperfusion. A small amount of constitutive NO synthase (cNOS) was expressed in liver endothelial cells after 6 h cold storage, but there was no expression of inducible NO synthase (iNOS). Expression of cNOS was particularly significant in vascular endothelial cells and liver cells at 3 h and 24 h after reperfusion in group II, but expression of iNOS and ICAM-1 was low in group I. There was diffuse strong expression of ICAM-1 and TNF-α in group III at 3 h after reperfusion.CONCLUSION: The NO/cGMP pathway may be critical in successful organ transplantation, especially in treating hepatopulmonary syndrome during cold IR injury in rat orthotopic liver transplantation.  相似文献   
50.
AIM: To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice.METHODS: Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity.RESULTS: Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling.CONCLUSION: Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.  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