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   3380篇
  免费   174篇
  国内免费   18篇
耳鼻咽喉   48篇
儿科学   145篇
妇产科学   153篇
基础医学   376篇
口腔科学   53篇
临床医学   313篇
内科学   747篇
皮肤病学   67篇
神经病学   299篇
特种医学   87篇
外科学   290篇
综合类   30篇
一般理论   1篇
预防医学   320篇
眼科学   122篇
药学   337篇
中国医学   2篇
肿瘤学   182篇
  2023年   23篇
  2022年   94篇
  2021年   143篇
  2020年   48篇
  2019年   73篇
  2018年   75篇
  2017年   71篇
  2016年   80篇
  2015年   92篇
  2014年   120篇
  2013年   147篇
  2012年   271篇
  2011年   251篇
  2010年   126篇
  2009年   124篇
  2008年   190篇
  2007年   175篇
  2006年   205篇
  2005年   191篇
  2004年   212篇
  2003年   174篇
  2002年   153篇
  2001年   45篇
  2000年   47篇
  1999年   46篇
  1998年   25篇
  1997年   20篇
  1996年   17篇
  1995年   10篇
  1994年   17篇
  1993年   7篇
  1992年   14篇
  1991年   24篇
  1990年   18篇
  1989年   23篇
  1988年   14篇
  1987年   19篇
  1986年   16篇
  1985年   19篇
  1984年   13篇
  1982年   8篇
  1980年   10篇
  1979年   10篇
  1978年   8篇
  1975年   7篇
  1974年   11篇
  1973年   10篇
  1972年   6篇
  1970年   11篇
  1967年   6篇
排序方式: 共有3572条查询结果,搜索用时 15 毫秒
31.
This paper presents a history of mental health nursing in Victoria, Australia from 1848 to the 1950's, or the asylum years to the era of the mental hospital. The research for this historical overview was conducted as part of a literature review for a mental health nursing doctoral thesis, which included an account of the evolution of the profession from asylum attendant to the present time. The literature reviewed for this project revealed a distinct lack of a coherent, chronological account of the historical development of mental health nursing in Victoria, and this paper seeks to address that knowledge gap.  相似文献   
32.
33.
HYPOTHESIS: Preoperative portal vein embolization (PVE) allows potentially curative hepatic resection without additional morbidity or mortality in patients with hepatobiliary malignancies who are marginal candidates for resection based on small liver remnant size. DESIGN: A retrospective review of a consecutive series of patients in a multi-institutional database who underwent extended hepatectomy. SETTING: University-based referral centers. PATIENTS: Forty-two patients underwent preoperative determination of the future liver remnant (FLR) volume before extended hepatectomy (> or = 5 segments) for hepatobiliary malignancy without chronic underlying liver disease. Patients were stratified by treatment with or without preoperative PVE. INTERVENTION: Preoperative percutaneous PVE. MAIN OUTCOME MEASURES: Clinical characteristics, FLR volume, operative morbidity, and survival. RESULTS: There was no difference between the groups that did and did not undergo PVE for the number of tumors, tumor size, estimated blood loss, duration of the operation, complexity of resection, or surgical margins. The FLR at presentation was significantly smaller in patients who underwent PVE than in patients who did not undergo PVE (18% vs 23%; P<.001). After PVE, FLR volumes increased significantly (P =.003); preoperative FLR volumes were similar in both groups (patients who underwent PVE, 25%; and patients who did not undergo PVE, 23%). There was no perioperative mortality and no statistical difference in the incidence of perioperative complications between those who did and those who did not undergo PVE (5 [28%] of 18 patients vs 5 [21%] of 24 patients). The overall 3-year survival was 65% and the median survival duration was equivalent in the 2 groups (40 vs 52 months for those who did vs those who did not undergo PVE). CONCLUSION: Portal vein embolization enables safe and potentially curative extended hepatectomy in a subset of patients who would otherwise be marginal candidates for resection based on a small liver remnant size.  相似文献   
34.
BACKGROUND: Lithium is commonly used to treat bipolar psychiatric disorders but can cause reduced urine concentrating ability. METHODS: To test whether lithium alters UT-A1 or UT-B urea transporter protein abundance or UT-A1 phosphorylation, rats were fed a standard diet supplemented with LiCl for 10 or 25 days, and then compared to pair-fed control rats. To investigate another potential mechanism for decreased urea transport, inner medullary collecting duct (IMCD) suspensions from lithium-fed or control rats were incubated with 32P-orthophosphate to measure the phosphorylation of UT-A1. RESULTS: In lithium-fed rats (25 days), UT-A1 abundance was reduced to 50% of control rats in IM tip and to 25% in IM base, and UT-B abundance was reduced to 40% in IM base. Aquaporin-2 (AQP2) protein abundance was reduced in both IM regions. Vasopressin (100 pmol/L) increased UT-A1 phosphorylation in IMCD suspensions from control but not from lithium-fed rats; a higher vasopressin concentration (100 nmol/L) increased UT-A1 phosphorylation in control and lithium-fed rats. CONCLUSIONS: Decreases in UT-A1, UT-B, and AQP2 protein abundance, and/or vasopressin-stimulated phosphorylation of UT-A1, can contribute to the reduced urine concentrating ability that occurs in lithium-treated rats.  相似文献   
35.
OBJECTIVE: Because chylothorax complicating thoracic surgery is difficult to diagnose and failure of nonoperative management necessitates further surgery, we critically evaluated an evolving percutaneous strategy for diagnosing and treating chylothorax. METHODS: After thoracic surgery, 37 patients with a clinical diagnosis of chylothorax were referred for lymphangiography for definitive diagnosis and percutaneous treatment. Successful localization of the cisterna chyli by lymphangiogram facilitated percutaneous cannulation of the thoracic duct and its embolization. In patients in whom cannulation was not possible, the thoracic duct was percutaneously disrupted. RESULTS: Diagnosis: Lymphangiography was successful in 36 of the 37 patients (97%). Contrast extravasation, confirming clinical diagnosis, was present in 21 of the 36 (58%). Management: Twenty-one of 36 patients underwent 22 lymphangiographically directed percutaneous interventions: 12 embolizations and 10 disruptions. Mortality was zero, with two manageable complications. Patients without percutaneous intervention were discharged a median of 7 days (range 4-58) after first lymphangiography, 8 days (range 2-19) after percutaneous embolization, and 19 days (range 6-48) after first disruption. Eight patients had nine subsequent reoperations for chylothorax, two with negative lymphangiograms; no embolization patient required reoperation. CONCLUSIONS: There is a discrepancy between the clinical diagnosis of chylothorax after thoracic surgery and the presumed gold standard of diagnosis, contrast extravasation at lymphangiogram. Percutaneous treatment by thoracic duct embolization or disruption is safe and may obviate reoperation, but embolization of the thoracic duct is preferable to its disruption.  相似文献   
36.
Reprinted from The American Journal of Physiology, Vol. 181, No.1, April, 1955.  相似文献   
37.
38.
Non‐HLA antibodies (Abs) targeting vascular receptors are thought to have an impact on renal transplant injury. Anti‐angiotensin II type 1‐receptor‐activating antibodies (anti‐AT1R) have been mentioned to stimulate a severe vascular rejection, but the pretransplant screening has not been introduced yet. The aim of our study was to assess the incidence and importance of anti‐AT1R antibodies and their influence on renal transplant in the 1st year of observation. We prospectively evaluated the presence of anti‐AT1R antibodies in 117 consecutive renal transplant recipients in pre‐ and post‐transplant screening. Anti‐AT1R antibodies were observed in 27/117 (23%) of the analyzed recipients already before transplantation. The function of renal transplant was considerably worse in anti‐AT1R(+) group. The patients with anti‐AT1R Abs >9 U/ml lost their graft more often. Biopsy‐proven AR was described in 4/27 (15%) pts in the anti‐AT1R(+) group and 13/90 (14.4%) in the anti‐AT1R(?) group, but more severe cases of Banff IIB or antibody‐mediated rejection (AMR) were more often observed in anti‐AT1R (+) 4/27 (15%) vs. 1/90 (1.1%) in anti‐AT1R(+) (P = 0.009). Patients with anti‐AT1R Abs level >9 U/ml run a higher risk of graft failure independently of classical immunological risk factors. The recipients with anti‐AT1R Abs developed more severe acute rejections described as IIB or AMR in Banff classification. More recipients among the anti‐AT1R‐positive ones lost the graft. Our study suggests monitoring of anti‐AT1R Abs before renal transplantation for assessment of immunologic risk profiles and the identification of patients highly susceptible to immunologic events, graft failure, and graft loss.  相似文献   
39.
Children with chronic kidney disease (CKD) are affected by cardiovascular complications, including disturbances in the intraventricular conduction system. Body surface potential mapping (BSPM) is a non-invasive method of assessing the cardioelectrical field. Our aim was to investigate conduction disturbances in young CKD patients using ventricular activation time (VAT) maps. Our study comprised 22 CKD children (mean age: 13.1 ± 2.5 years) treated conservatively and 29 control patients. For each child 12-lead electrocardiogram (ECG) readings were taken, and blood pressure and serum concentrations of iPTH, Pi, t-Ca, creatinine, Fe+3, ferritin, and Hb, as well as eGFR were measured. All children underwent registration in the 87-lead BSPM system, and group-mean VAT maps and a difference map, which presents statistically significant differences between the groups, were created. The VAT map distribution in CKD patients revealed abnormalities specific to left anterior fascicle block. The difference map displays the areas of intergroup VAT changes, which are of discriminative value in detecting intraventricular conduction disturbances. Intraventricular conduction impairments in the left bundle branch may occur in children with CKD. BSPM enables conduction disturbances in CKD children to be detected earlier than using 12-lead ECG. The difference map derived from the group-mean isochrone maps precisely localizes the sites of disturbed conduction in the heart intraventricular conduction system.  相似文献   
40.
Urea plays a critical role in the urine-concentrating mechanism in the inner medulla. Physiologic data provided evidence that urea transport in red blood cells and kidney inner medulla was mediated by specific urea transporter proteins. Molecular approaches during the past decade resulted in the cloning of two gene families for facilitated urea transporters, UT-A and UT-B, encoding several urea transporter cDNA isoforms in humans, rodents, and several nonmammalian species. Polyclonal antibodies have been generated to the cloned urea transporter proteins, and the use of these antibodies in integrative animal studies has resulted in several novel findings, including: (1) the surprising finding that UT-A1 protein abundance and urea transport are increased in the inner medulla during conditions in which urine concentrating ability is reduced; (2) vasopressin increases UT-A1 phosphorylation in rat inner medullary collecting duct; (3) UT-A protein abundance is upregulated in uremia in both liver and heart; and (4) UT-B is expressed in many nonrenal tissues and endothelial cells. This review will summarize the knowledge gained from using molecular approaches to perform integrative studies into urea transporter protein regulation, both in normal animals and in animal models of human diseases, including studies of uremic rats in which urea transporter protein is upregulated in liver and heart.  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