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   53378篇
  免费   2745篇
  国内免费   1261篇
耳鼻咽喉   269篇
儿科学   1493篇
妇产科学   239篇
基础医学   2600篇
口腔科学   96篇
临床医学   8301篇
内科学   9705篇
皮肤病学   286篇
神经病学   2380篇
特种医学   1563篇
外科学   4634篇
综合类   10774篇
现状与发展   1篇
预防医学   4512篇
眼科学   247篇
药学   6423篇
  50篇
中国医学   2324篇
肿瘤学   1487篇
  2024年   83篇
  2023年   623篇
  2022年   1555篇
  2021年   2070篇
  2020年   1836篇
  2019年   1441篇
  2018年   1493篇
  2017年   1665篇
  2016年   1939篇
  2015年   1830篇
  2014年   4439篇
  2013年   4345篇
  2012年   3869篇
  2011年   3984篇
  2010年   3113篇
  2009年   2672篇
  2008年   2650篇
  2007年   2673篇
  2006年   2376篇
  2005年   1949篇
  2004年   1563篇
  2003年   1303篇
  2002年   968篇
  2001年   898篇
  2000年   740篇
  1999年   670篇
  1998年   531篇
  1997年   492篇
  1996年   418篇
  1995年   426篇
  1994年   361篇
  1993年   247篇
  1992年   217篇
  1991年   226篇
  1990年   204篇
  1989年   180篇
  1988年   176篇
  1987年   132篇
  1986年   112篇
  1985年   174篇
  1984年   137篇
  1983年   73篇
  1982年   93篇
  1981年   82篇
  1980年   78篇
  1979年   57篇
  1978年   55篇
  1977年   53篇
  1976年   32篇
  1975年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
目的 :了解高原康胶囊对快速进入高原者血浆醛固酮 (Aldosterone ,ALD)、血管紧张素II(AngiotensinII ,AII)及水负荷的影响及意义。方法 :将 80名由平原快速进入高原的新兵随机分为实验组 4 0名 ,对照组 4 0名 ,实验组于平原登机前开始给予口服高原康胶囊 ,连服 3日 ,对照组给予安慰剂 ,两组均于进入高原的前 1天及进入高原的第 3天午给予水负荷实验 ,并对饮水前血浆ALD、AII及饮水后 15 0min内各时间段的尿量及两组进入高原后 7天内急性高原病 (Acutehighal titudediseaes ,AHAD)的发病率进行对照比较。结果 :对照组进入高原后与平原相比血浆ALD、AII显著升高 ,水负荷实验 6 1min~ 15 0min各时间段的尿量及相应时间的总尿量与平原时相应各时间段的尿量及相应时间的总尿量相比则显著减少 (P <0 0 5~ 0 0 0 1) ,而实验组则无显著变化 (P >0 0 5 ) ;进入高原后实验组与对照组相比水负荷实验 6 1min~ 90min的尿量及 12 0min、15 0min的尿总量则显著多于对照组 (P <0 0 5 ) ;血浆ALD、AII及AHAD发病率则显著低于对照组 (P <0 0 5~ 0 0 0 1)。结论 :高原康胶囊能显著降低快速进入高原者的血浆ALD、AII ,通过对水负荷调节的影响减少机体的钠水潴留 ,从而防止快速进入高原者AHAD的发生 ,可用于大批快  相似文献   
72.
急性心肌梗死后室间隔穿孔患者的外科治疗   总被引:1,自引:0,他引:1  
目的:探讨急性心肌梗死(AMI)后室间隔穿孔(VSR)的外科治疗方法和结果。方法:回顾分析手术治疗的8例急性心肌梗死后室间隔穿孔患者的临床资料。男性7例,女性1例,年龄62~74岁,平均年龄67.5岁,均有急性心肌梗死史,4例有高血压病史,2例有糖尿病史,6例合并室壁瘤。心功能NYHAⅢ级6例,Ⅳ级2例。术前射血分数(EF)值33%~71%,平均54.5%。患者心肌梗死至手术的间隔时间平均为5.4周。所有患者均采用牛心包补片旷置室间隔穿孔,7例患者同期行冠状动脉旁路移植术,平均2.7支/例。结果:手术死亡2例,死亡率25%。其中1例因多脏器功能衰竭于术后32 d死亡,另1例因肾功能不全于术后6 d死亡。存活6例随访3~24个月,平均13.2个月,无晚期死亡,无心血管事件。心功能NYHAⅠ级5例,Ⅱ级1例。术后EF值50%~66%,平均58.3%。结论:掌握适当的手术时机、完善的术前准备、积极的围手术期治疗、准确的手术操作和避免术后并发症的发生,能有效地降低急性心肌梗死后室间隔穿孔患者的死亡率,改善其预后。  相似文献   
73.
目的:观察急性迟缓性麻痹病例(AFP)在我市的发病状况。方法:对96例急性迟缓性麻痹病人采集48h内粪便进行病毒分离,并进行个案调查与随访。结果:96例中,7例分布于城镇,89例分布于农村;格林-巴利综合征55例(57.3%)-横断性脊髓炎16例(16.6%)、神经炎11例(11.5%)、重症肌无力12例(12.5%)、与疫苗相关的脊髓灰质炎AFP病例(VAPP)2例(2.08%)。结论:防疫部门与各级医院加强合作和直接管理能及时了解发病状况。市髓灰质炎减毒疫苗(OPV)免疫工作尚存不足,宣讲教育应进一步加强。  相似文献   
74.
赵晓伟  赵晓宏 《实用医技杂志》2007,14(18):2560-2561
脑梗死急性期对血压和颅压的控制极为重要,若措施得当,可大大降低病死率和致残率。笔者结合临床工作经验总结体会如下:脑梗死急性期对血压和颅压的控制极为重要,若措施得当,可大大降低病死率和致残率,笔者结合临床工作经验总结体会如下。  相似文献   
75.
21例心内直视术后急性心包填塞的临床分析   总被引:1,自引:1,他引:0  
目的:分析21例心内直视术后急性心包填塞的临床特点,探讨其发生原因、预防、救治及其二次开胸的早期指征。方法:对1991年1月-2005年12月心内直视术(共1096例)后21例急性心包填塞二次开胸(发生率1.92%)病例进行总结分析。结果:急性心包填塞患者经二次剖胸解除心包填塞后17例痊愈出院,4例死亡,二次剖胸手术死亡率为19.05%。二次剖胸手术者所患疾病包括先天性心脏病6例,瓣膜病13例,大血管手术1例,心脏移植1例。结论:减少心内直视术后出血、渗血是避免术后发生急性心包填塞的关键,早期诊断并尽早行二次剖胸手术可明显降低围手术期死亡率。  相似文献   
76.
Lymphoid clusters (LC) containing CD20-positive B cells in kidney allografts undergoing acute cellular rejection (ACR) have been identified in small studies as a prognostic factor for glucocorticoid resistance and graft loss. Allograft biopsies obtained during the first episode of ACR in 120 recipients were evaluated for LC, immunostained with CD20 antibody, and correlated with conventional histopathologic criteria, response to treatment and outcome. LC were found in 71 (59%) of the 120 biopsies. All contained CD20 positive B cells that accounted for 5-90% of the LC leukocyte content. The incidence of LC was highest in the patients who had no lymphoid depletion or had been treated with Thymoglobulin preconditioning (79% vs. 75%, respectively) compared to 37% in patients pretreated with Campath (p = 0.0001). Banff 1a/1b ACR were more frequent in the LC-positive than the LC-negative group (96% vs. 80%, respectively; p = 0.0051). With a posttransplant follow-up of 953 +/- 430 days, no significant differences were detected between LC-postitive and LC-negative groups in time to ACR, steroid resistance, serum creatinine and graft loss. CD20+LC did not portend glucocorticoid resistance or worse short to medium term outcomes. CD20+LC may represent a heterogenous collection in which there may be a small still to be fully defined unfavorable subgroup.  相似文献   
77.
目的 探讨高龄急性脑梗死患者接受阿替普酶静脉溶栓治疗有效性、安全性和临床预后的影响
因素。
方法 前瞻性连续纳入江苏省苏北人民医院2016年9月-2018年9月收治入院进行阿替普酶静脉溶
栓治疗的急性脑梗死患者,按照年龄将患者分为年龄≥80岁组和年龄<80岁组。比较两组患者入院
时、溶栓24 h NIHSS评分,6个月mRS评分及死亡率,观察两组溶栓相关出血转化、症状性颅内出血及
肺部感染的发生情况。应用多因素Logistic回归分析观察所有患者静脉溶栓预后的独立影响因素。
结果 最终共纳入患者119例,男性69例(58.0%),年龄范围46~94岁,平均70.12±10.55岁,入院
NIHSS评分4~38分。其中年龄≥80岁患者29例,年龄<80岁患者90例。静脉溶栓后,两组患者溶栓
24 h NIHSS评分较入院时均明显降低(均P<0.05),两组治疗24 h NIHSS评分比较差异无统计学意义;
两组的出血转化、症状性颅内出血、肺部感染、6个月预后良好及死亡率比较,差异均无统计学意义。
多因素Logistic回归分析显示,入院到静脉溶栓时间、入院时NIHSS评分及肺部感染是脑梗死静脉溶
栓6个月预后的独立危险因素(P<0.05),高龄不是影响预后的因素(P>0.05)。
结论 高龄急性脑梗死患者静脉溶栓治疗安全有效,未增加颅内出血转化风险、死亡率及不良预
后。入院到静脉溶栓时间、入院时NIHSS评分及肺部感染是急性脑梗死患者静脉溶栓6个月预后不良
的独立危险因素。  相似文献   
78.
Purpose Studies on musculoskeletal manifestations (MSM) of childhood acute lymphoblastic leukemia (ALL) have yielded variable findings with regard to their clinical impact. We investigated the significance for differential diagnosis, treatment and outcome of musculoskeletal complaints as presenting symptoms of ALL, and their correlation with leukemia immunophenotypes, for which data is lacking. Methods Data on 783 children in the national study for childhood ALL between 1984 and 2003 were reviewed retrospectively. Statistical analysis examined possible relationships between MSM at the time of diagnosis and demographic and clinical data, biological features of leukemia (peripheral blood counts, immunophenotype and main cytogenetic aberration), response to initial prednisone treatment, and outcome. Results Of 765 children with data on orthopaedic complaints, 240 presented with MSM (31.4%). Among these children, B cell precursor (BCP) was much more common (209/576, 36.3%) than T cell ALL (25/176, 14.2%). Patients with MSM had lower white blood cell counts (WBC) (median of 9 vs. 20 × 109/L, P < 0.001) and percentage of blast cells in the peripheral blood at diagnosis compared to those without (median of 27 vs. 53%, P < 0.001). Hepatomegaly and splenomegaly were less common in MSM group (67 vs. 53% <3 cm, P < 0.001, and 63 vs. 50% <3 cm, P < 0.001, respectively). Poor response to initial treatment with prednisone was recorded in 7.1% of patients with MSM versus 11.5% of those without (P = 0.086). The analysis revealed no independent effect of MSM on event-free survival (EFS), after correcting for differences in EFS related to immunophenotype or initial WBC. Conclusions MSM occur mostly in children with BCP ALL who present with less involvement of extramedullary organs, low peripheral blood blasts and white blood cells counts. These findings highlight the importance of including ALL in the differential diagnosis of MSM even in the presence of an apparently normal peripheral blood count. Our study also suggests that MSM are caused by leukemic cells with enhanced biological propensity to remain relatively confined within the intramedullary bone-marrow space.  相似文献   
79.
Brain-dead donors are the major source of lungs for transplantation. Brain death is characterized by two hemodynamic phases. Initially, massive sympathetic discharge results in a hypertensive crisis. This is followed by neurogenic hypotension. Up-regulation of pro-inflammatory mediators occurs in all organs and lung injury develops; this can adversely affect graft function post-transplantation. The mechanisms of the systemic and lung inflammation are unknown. We hypothesized that the hemodynamic changes are responsible for these inflammatory phenomena. Brain death was induced by intra-cranial balloon inflation in rats. This resulted in hypertensive crisis, followed by hypotension. There was a significant increase in blood neutrophil CD11b/CD18 expression and pro-inflammatory cytokine levels in serum and bronchoalveolar lavage, compared with control animals. Rupture of the capillary-alveolar membrane was demonstrated by electron microscopy. Elimination of the hypertensive response by α-adrenergic antagonist pre-treatment prevented inflammatory lung injury, reduced the systemic inflammatory markers and preserved capillary-alveolar membrane integrity. Correction of the neurogenic hypotension with noradrenaline ameliorated the systemic inflammatory response and improved oxygenation. We conclude that the sympathetic discharge triggers systemic and lung inflammation, which can be further enhanced by neurogenic hypotension. Management of the brain-dead donor with early anti-inflammatory treatment and vasoconstrictors is warranted.  相似文献   
80.
Asthma patients that depend on emergency department (ED) services are generally considered to have extremely poor disease control and prognosis. It is important to identify characteristics related to poor disease control and frequent visits to the ED to apply appropriate clinical management. This study comprised a cross-sectional survey of consecutive patients with asthma exacerbation (age ≥12 years) presenting at the adult ED of a large, tertiary care, university-affiliated hospital over a 2-month period. The frequent visitors (FV) were defined by ≥3 visits to the ED in the preceding year, and the occasional visitors (OV) by ≤2 visits. Eighty-six patients (61 females and 25 males) were included in the study (mean age 38 ± 18 years). Of these patients, 51.2% were FV and 48.8% were OV. Sixty-nine percent had annual income lower than A$3000 and 66.3% had ≤8 years of the formal education. Only 18.6% had used inhaled corticosteroids, 79.1% identified the asthma attack severity, 70.9% increased or initiated inhaled β-agonist, 20.9% increased or initiated steroid therapy, and 55.8% had an asthma action plan for attack. The number of hospital admissions in past year (OR 4.3, P = .02), use of home nebulizer (OR 3.6, P = .05) and the lack of a written asthma action plan (OR 3.3, P = .03) were independently associated with frequent visits to the ED. We conclude that a substantial proportion of the patients that visit the ED are FV. These patients are more likely to have hospital admission in the past year, to use a home nebulizer, and to lack a written asthma action plan. They should be considered the most important target for asthma education.  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