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   16113篇
  免费   867篇
  国内免费   662篇
耳鼻咽喉   513篇
儿科学   1033篇
妇产科学   122篇
基础医学   481篇
口腔科学   60篇
临床医学   1662篇
内科学   2793篇
皮肤病学   29篇
神经病学   108篇
特种医学   1149篇
外国民族医学   2篇
外科学   4772篇
综合类   2179篇
预防医学   409篇
眼科学   410篇
药学   853篇
  4篇
中国医学   562篇
肿瘤学   501篇
  2024年   26篇
  2023年   205篇
  2022年   429篇
  2021年   559篇
  2020年   487篇
  2019年   478篇
  2018年   487篇
  2017年   419篇
  2016年   565篇
  2015年   525篇
  2014年   1010篇
  2013年   924篇
  2012年   880篇
  2011年   1033篇
  2010年   887篇
  2009年   887篇
  2008年   898篇
  2007年   938篇
  2006年   835篇
  2005年   682篇
  2004年   579篇
  2003年   464篇
  2002年   433篇
  2001年   375篇
  2000年   318篇
  1999年   247篇
  1998年   229篇
  1997年   219篇
  1996年   175篇
  1995年   172篇
  1994年   134篇
  1993年   100篇
  1992年   103篇
  1991年   82篇
  1990年   109篇
  1989年   70篇
  1988年   92篇
  1987年   57篇
  1986年   57篇
  1985年   70篇
  1984年   77篇
  1983年   40篇
  1982年   58篇
  1981年   45篇
  1980年   42篇
  1979年   41篇
  1978年   25篇
  1977年   21篇
  1976年   22篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Damus–Kaye–Stansel procedure is a useful method to relieve the systemic ventricular outflow tract obstruction in functionally univentricular heart. Regurgitation of pulmonary valve and recurrence of systemic ventricular outflow obstruction are the major concerns at the late phase of this procedure. Modification of original Damus–Kaye–Stansel procedure that can prevent the use of prosthetic materials is evaluated. The modified Damus–Kaye–Stansel procedure using aortic flap technique was performed in eight patients with functionally univentricular heart. Patients’ ages ranged from 3 to 28 months (mean 14 months). Follow-up period was 37 months as a mean (9–71 months), and the follow-up was complete. There was no operative mortality and no late death. In addition, there was no recurrence of systemic ventricular outflow tract obstruction throughout the follow-up period. Regurgitation of the pulmonary valve estimated by echocardiography at the latest follow-up was none to trivial in seven patients and mild in one. The modified Damus–Kaye–Stansel procedure using aortic flap technique is a safe, useful and reproducible technique to solve systemic ventricular outflow tract obstruction in functionally univentricular heart, and it can be an alternative for original technique or the so-called double-barrel modification.  相似文献   
102.
MRI evaluations of intramyocardial hemorrhage in acute infarction have relied on T(2) and T(2)(*) shortening only. We propose a more comprehensive evaluation of hemorrhagic infarction based on the concept that fluctuations in T(2) and T(1) relaxation in acute reperfused infarction will reflect transient edema and hemoglobin oxidative denaturation to uncompartmentalized methemoglobin. Anteroapical infarction was created via percutaneous balloon in young swine (22-25 kg, N = 12). T(2), T(1), diastolic wall thickness (DWT), and the Gd-DTPA partition coefficient (lambda) were measured on days 0, 2, and 7. DWT was elevated at 1 hr postreperfusion (128% +/- 53%, P = 0.0001), and alleviated on days 2 and 7 (48% +/- 10%, P = 0.008; 53% +/- 24%, P = 0.003). T(2) and T(1) elevations were coincident with early edema (DeltaT(2) = 55% +/- 24%, P < 0.0001; DeltaT(1) = 27% +/- 18%, P < 0.04). T(2) and T(1) were nearly normal on day 2 (DeltaT(2) = 8% +/- 8%, P = 0.27; DeltaT(1) = 0% +/- 1%, P = 0.65). On day 7, T(2) increased while T(1) decreased (DeltaT(2) = 27% +/- 16%, P = 0.005; DeltaT(1) = -14% +/- 10%, P = 0.02). Lambda was elevated by >150% at all time points (P < or = 0.002). Histology verified hemorrhagic injury. T(1) and T(2) fluctuations are consistent with transient edema, as well as hemoglobin oxidative denaturation to decompartmentalized methemoglobin. This methodological development may broaden our understanding of hemorrhagic microvascular injury and improve its detection in clinical populations.  相似文献   
103.
The posterior urethral valve uropathy: Results of treatment   总被引:2,自引:0,他引:2  
Nineteen children treated for posterior urethral obstruction due to congenital valve in the University of Benin Teaching Hospital, Benin City, Nigeria, over a 9-year period have been analysed. Their ages ranged from birth to 12 years. Results show that associated kidney pathology may be irreversible even after successful excision of the valve. This determines the final prognosis, which is worse the younger the child at presentation.  相似文献   
104.
105.
目的:探讨诱导型一氧化氮合酶(iNOS)在单侧输尿管梗阻(UUO)大鼠术侧肾脏的表达.方法:建立左侧输尿管梗阻模型(UUO组),设假手术组为对照.3 d后应用逆转录-聚合酶链反应(RT-PCR)检测iNOS的mRNA水平.结果:与对照组相比,UUO组大鼠肾脏出现明显病理变化,并且其iNOS mRNA表达明显增加.结论:iNOS参与UUO的发生和发展的病理过程.  相似文献   
106.
Cardiac malignant mesenchymoma is an extremely rare malignancy with poor prognosis. We report a patient presenting with a history and clinical findings typical of mitral stenosis. Transthoracic echocardiography showed a mass on the thickened posterior mitral leaflet. Transoesophageal echocardiography revealed two tumoural masses: one on the atrial side of the posterior mitral leaflet causing mitral obstruction, the other arising in the region of the right lower pulmonary vein orifice and obstructing inflow through this vein.  相似文献   
107.
植入镍钛记忆合金支架治疗恶性胆道梗阻的临床分析   总被引:2,自引:0,他引:2  
目的 评价植入镍钛记忆合金支架治疗恶性胆道梗阻的疗效。方法 对16例恶性胆道梗阻患者。采用经手术及介入方法植入镍钛记忆合金胆道支架。结果 术后1个月内死亡1例,15例黄疸完全解除。随访15例,12例术后平均生存13.1个月。结论 植入镍钛合金胆道支架可提高姑息切除的疗效;对不能切除病灶患者,支架植入可解除黄疸,改善生活质量。  相似文献   
108.
AIM:To determine if novel bile acid transporters may be expressed in human tissues.METHODS:SLC10A1 (NTCP) was used as a probe to search the NCBI database for homology to previously uncharacterized ESTs. The homology search identified an EST (termed SLC10A4) that shares sequence identity with SLC10A1 and SLC10A2 (ASBT). We performed Northern blot analysis and RT-PCR to determine the tissue distribution of SLC10A4. SLC10A4 was cloned in frame with an epitope tag and overexpressed in CHO cells to determine cellular localization and functional analysis of bile acid uptake.RESULTS:Northern analysis revealed that SLC 10A4 mRNA is ubiquitously expressed fn human tissues with the highest levels of mRNA expression in brain,placenta, and liver. In SLC10A4-transfected CHO cells,immunoblotting analysis and immunofluorescence staining demonstrated a 49-kDa protein that is expressed at the plasma membrane and intracellular compartments.Functional analysis of SLC10A4 showed no significant taurocholate uptake in the presence of sodium when compared to untransfected CHO cells.CONCLUSION:To date, we have shown that this protein has no capacity to transport taurocholate relative to SLC1041; however, given its ubiquitous tissue distribution, it may play a more active role in transporting other endogenous organic anions.  相似文献   
109.
110.
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