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   21723篇
  免费   1956篇
  国内免费   1495篇
耳鼻咽喉   214篇
儿科学   157篇
妇产科学   271篇
基础医学   2493篇
口腔科学   237篇
临床医学   2579篇
内科学   3656篇
皮肤病学   204篇
神经病学   1063篇
特种医学   824篇
外国民族医学   14篇
外科学   2351篇
综合类   3708篇
现状与发展   1篇
一般理论   2篇
预防医学   1262篇
眼科学   588篇
药学   2379篇
  21篇
中国医学   1196篇
肿瘤学   1954篇
  2024年   83篇
  2023年   361篇
  2022年   881篇
  2021年   1161篇
  2020年   803篇
  2019年   734篇
  2018年   833篇
  2017年   686篇
  2016年   689篇
  2015年   996篇
  2014年   1225篇
  2013年   1013篇
  2012年   1557篇
  2011年   1697篇
  2010年   969篇
  2009年   843篇
  2008年   1166篇
  2007年   1111篇
  2006年   1077篇
  2005年   1031篇
  2004年   717篇
  2003年   662篇
  2002年   597篇
  2001年   516篇
  2000年   576篇
  1999年   510篇
  1998年   365篇
  1997年   333篇
  1996年   289篇
  1995年   277篇
  1994年   193篇
  1993年   137篇
  1992年   172篇
  1991年   165篇
  1990年   129篇
  1989年   127篇
  1988年   114篇
  1987年   101篇
  1986年   96篇
  1985年   61篇
  1984年   29篇
  1983年   24篇
  1982年   11篇
  1981年   17篇
  1980年   10篇
  1979年   7篇
  1978年   7篇
  1977年   3篇
  1976年   4篇
  1974年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Limited evidence has indicated that brain-derived neurotrophic factor (BDNF) may be involved in the neurobiology of premature ejaculation (PE). This study aimed to investigate BDNF levels in the central and peripheral nervous systems of a rapid ejaculation model. Eighteen male rats were selected and classified as ‘sluggish’, ‘normal’ and ‘rapid’ ejaculators on the basis of ejaculation frequency during copulatory behavioural tests. BDNF levels in specific brain regions, spinal cord and serum were determined by enzyme-linked immunosorbent assay (ELISA). Consistent with the results in PE patients, the concentration of serum BDNF decreased significantly from the sluggish rats to normal and rapid rats. Besides, in both brain regions and spinal cord, the sluggish group had the highest BDNF levels, while the rapid group had the lowest BDNF levels. Regression analyses of the expression of BDNF presented positive correlations between serum and brain (r = 0.958, p < .001), and between serum and spinal cord (r = 0.967, p < .001) respectively. Our findings suggested insufficient BDNF in the nervous system and serum may lead to rapid ejaculation. The current study adds to the evidence that BDNF is involved in the regulation of ejaculation.  相似文献   
92.
Dai  Wei  Zhuang  Zong  Ling  Haiping  Yang  Yongbo  Hang  Chunhua 《Neurosurgical review》2021,44(1):515-527
Neurosurgical Review - To quantitatively synthesize the comparative efficacy and safety of the most common surgical approaches including endonasal transsphenoidal endoscopic surgery (ETES),...  相似文献   
93.
94.
目的探讨完全右半肝-左半肝劈离式肝移植在成人-成人或成人-大体重儿童中的临床应用。方法回顾2019年1月至12月间首都医科大学附属北京友谊医院完成的4例完全右半肝-左半肝劈离式肝移植的供受者临床资料,分析劈离式肝移植的手术方式、冷缺血时间、手术时间、术中输血量,观察患者术后并发症及相关预后。结果4例完全右半肝-左半肝劈离式肝移植的受者包括3例成人和1例大体重儿童(45 kg),年龄范围14~48岁,体重范围45~61 kg,终末期肝病模型评分分别为21、12、41和30分。移植物质量与受者体质量比为0.85%~1.35%。冷缺血时间457~650 min,手术时长460~575 min。4例患者移植术后早期肝功能恢复顺利,均未出现小肝综合征。随访至术后6个月,其中1例出现胆道吻合口漏,经内镜逆行胰胆管造影术治疗后治愈;1例出现胆道狭窄,经皮肝穿刺胆道引流术治疗后反复胆道感染;1例术后6个月死于肺部感染。结论在严格病例选择的情况下,可以开展完全右半肝-左半肝劈离式肝移植。  相似文献   
95.
This case series reports the outcome of posterior ankle decompression and os trigonum or Stieda process resection utilizing an open posterolateral approach in 54 professional, pre-professional, and dedicated recreational dancers. All procedures were performed by a single surgeon at the same facility between 2008 and 2018. The surgical technique is described in detail. Data related to results of the surgery were gathered via follow-up questionnaire and verified by referencing the patients’ medical records. Outcomes were self-assessed in terms of categories ranging from excellent through moderate to poor. Eighty-nine percent of the dancers (N = 48 of 54) chose excellent or good, 11% (N = 6) chose moderate, and none selected poor. These results were compared with those achieved in 17 previous studies reporting the use of both open (posterolateral and posteromedial) and arthroscopic/endoscopic techniques in dancers. This comparison found similarly favorable reported outcomes, but also great variation in methodology for determining patient reported outcomes (PROs). While the preferred surgical technique for posterior ankle decompression remains controversial, the open posterolateral approach utilized in this series resulted in high expectation of return to dance with minimal complications. The need for a dancer-specific PRO tool is discussed.  相似文献   
96.
PurposeTo investigate the clinical characteristics, chemosensitivity, and outcome of metastatic upper tract urothelial carcinoma (UTUC).Patients and MethodsRecords of patients with metastatic UTUC since January 2005 were retrieved from a database that included clinical and survival data. Statistical analyses including survival and multivariate analyses of factors were respectively performed by the Kaplan-Meier method and Cox proportional hazard model.ResultsA total of 250 consecutive UTUC cases were evaluated. There were 56 patients (22.4%) with initially diagnosed stage IV disease. The most common metastatic sites were lung (39.6%), distant lymph nodes (39.2%), bone (19.6%), liver (18.0%), and adrenal gland (7.2%), respectively, and the local recurrence rate was 10.4%. Two hundred thirteen patients received first-line chemotherapy. The overall response rate was only 28.7% and the median progression-free survival time was only 5.0 months. The overall survival time of the cohort was 18.0 months. Multivariate analyses showed that initially diagnosed stage IV disease, number of metastatic organs ≥3, no response to chemotherapy and cycles of chemotherapy ≤2 were adverse prognosticators for overall survival.ConclusionUTUC presented to be more prone to metastasize than locally recur and thought to have low chemosensitivity. Stage IV disease at initial diagnosis, number of metastatic organs, response and cycles of chemotherapy were independent prognosticators for metastatic UTUC.  相似文献   
97.
目的探究人文医疗在阴式全子宫切除术联合阴道后壁修补术治疗老年子宫脱垂合并肠疝(阴道后壁膨出)患者中的应用效果。方法选择2018年1月至2019年12月期间天长市中医院收治子宫脱垂合并肠疝患者120例作为研究对象。全部入选病例均行阴式全子宫切除术联合阴道后壁修补术治疗,采用随机数字表法将病例分为对照组和观察组,各60例。对照组给予常规护理,观察组给予人文医疗护理。对比2组患者中文版知觉压力量表(CPSS)评分、抑郁自评量表(SDS)、焦虑自评量表(SAS)评分、心理弹性量表-简表(RS-14)、护理服务满意度、皮质醇(Cor)、心率及平均动脉压。结果护理前,2组CPSS、SDS、SAS及RS-14评分组间比较的差异无统计学意义(P>0.05);护理7 d后,2组CPSS、SDS、SAS及RS-14评分均较护理前降低,且观察组均低于对照组,差异有统计学意义(P<0.05)。观察组患者的满意度(96.67%)较对照组高(80.00%),差异有统计学意义(P<0.05)。观察组手术结束时2组患者的Cor、心率及平均动脉压较对照组低,差异有统计学意义(P<0.05)。结论人文医疗应用于子宫脱垂合并肠疝患者护理中,能够改善其不良情绪,缓解心理压力,减少手术的应激反应,提高患者对护理满意度。  相似文献   
98.
ObjectiveTo investigate the risk factors for, and outcomes of, preoperative asymptomatic pulmonary embolism (PE) in patients ≥60 years old following delayed operation for hip fracture.MethodsFrom March 2017 to December 2018, 90 patients aged ≥60 years with hip fracture who suffered a delay in surgery were recruited to this prospective study following admission to our hospital. Computed tomography pulmonary angiography (CTPA) was used to detect preoperative asymptomatic PE and calculated its incidence. Time from injury to admission, baseline characteristics, medical comorbidities, and blood biomarker levels were evaluated as potential risk factors. Logistic regression analysis was used to identify risk factors. Mortality and major bleeding events were recorded and compared between individuals with PE and without. Data were analyzed by t‐test, Mann–Whitney U test, χ 2 test, Fisher''s exact test, and logistic regression analysis.ResultsThe incidence of preoperative asymptomatic PE was 18.9% (17/90 patients). In the univariate analysis, the risk factors for preoperative asymptomatic PE were male sex, hypertension, cerebrovascular accident, smoking, plasma D‐dimer level, potassium level, urea level, creatinine level, and cysteine level. Multivariate logistic regression analysis showed that the risk of preoperative asymptomatic PE was higher in patients with hypertension (odds ratio [OR] = 10.048; 95% confidence interval [CI], 1.118–90.333), cerebrovascular accident (OR = 20.135; 95% CI, 1.875–216.164), smoking (OR = 48.741; 95% CI, 4.155–571.788), high plasma D‐dimer levels (OR = 1.200; 95% CI, 1.062–157.300), and high plasma potassium levels (OR = 12.928; 95% CI, 1.062–157.300). All patients were followed up for 21.0 months (range, 2 to 36 months). Mortality within the first year postoperatively was higher in patients with PE (29.41% vs 9.59%, P = 0.046).ConclusionsIn view of the high incidence of preoperative asymptomatic PE and the inferior prognosis in individuals with PE, routine CTPA examination for preoperative asymptomatic PE could be useful for patients aged ≥60 years with hip fracture for whom surgery is delayed.  相似文献   
99.
W Mao  L Zeng  Q Ma  Y Chen  Z Dai  P Tang  X Guo  D Li  W Su 《眼科学报》1990,6(3-4):88-90
We report here the preliminary effects of zinc iontophoresis in treatment of 26 Rp patients who had decreased zinc serum level or abnormal ratio of serum copper to zinc. Through more than 20 to 30 times of therapy, the vision of 15.38% eyes increased more than "3 lines", 4% eyes increased more than 5 degrees in the visual field, 13.46% eyes improved in dark adaptation threshold (greater than 1.0), the visual functions of the rest eyes were slightly improved or unimproved. The fundus didn't change before & after treatment. There were no changes of ERG in 8 eyes of 4 cases. In addition, the advantages and disadvantages between Zn iontophoresis and Zn compound taken orally, the improvement of vision by direct electric current therapy, the relationship between the metabolism of Zn element and Vit A and influence of Zn over the mechanism of dark adaptation were also briefly discussed.  相似文献   
100.
目的 建立血管性血友病因子(vWF)基因Rsa I、Sma I多态性寡核苷酸阵列检测方法,对基因芯片在单核苷酸多态性(SNP)检测上的应用进行探讨;研究两位点多态性与血栓性疾病的发生有无相关关系。方法 设计、合成两组寡核苷酸探针,使用3甲氧基氨基丙基硅烷、戊二醛等化学物质,实现探针与固相支持物玻片的连接。 应用不对称PCR方法扩增Rsa I、Sma I多态性片段,在扩增体系中掺入荧光标记dUTP,获得被测片段的单链标记产物。对核酸杂交反应的温度、动力学和离子浓度 变化进行研究,获得最佳的杂交鉴别条件。对20名正常人,酶切法确定多态性基因型,再用寡核苷酸阵列法检测,以验证该方法的准确性。使用该方法对50例血栓病人进行检测,探讨血栓性疾病的发生与vWF基因Rsa I、Sma I多态性的关系。结果 寡核苷酸阵列法和酶切法对20例标本检测的符合率为1005;血栓病人与正常人Rsa I、Sma I两位点多态性的基因型GG、GA、AA和CC、CT、TT分别为4.0%、12.0%、84.0%和24.0%、44.0%、32.0%,正常人分别为1.4%、11.8%、86.8%和8.8%、57.4%、33.8%,血栓病人等位基因频率G、A和C、T分别为10.0%、90.0%和46.0%、54.0%,正常人分别为7.4%、92.6%和37.5%、62.5%,血栓病人与正常人之间两位点多态性的基因型和等位基因频率的差异均无显著意义(P>0.05)。结论 成功建立vWF基因 Rsa I、Sma I多态性寡核苷酸阵列检测方法,为基因芯片技术在SNP检测上的应用提供依据。未获明确证据表明Rsa I、Sma I多态性与血栓的发生有关。  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