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   1110篇
  免费   84篇
  国内免费   18篇
耳鼻咽喉   3篇
儿科学   34篇
妇产科学   12篇
基础医学   130篇
口腔科学   6篇
临床医学   87篇
内科学   204篇
皮肤病学   60篇
神经病学   152篇
特种医学   116篇
外科学   136篇
综合类   32篇
预防医学   50篇
眼科学   4篇
药学   129篇
  1篇
肿瘤学   56篇
  2021年   11篇
  2020年   7篇
  2019年   20篇
  2018年   21篇
  2017年   16篇
  2016年   12篇
  2015年   18篇
  2014年   15篇
  2013年   26篇
  2012年   29篇
  2011年   35篇
  2010年   26篇
  2009年   33篇
  2008年   42篇
  2007年   44篇
  2006年   39篇
  2005年   40篇
  2004年   27篇
  2003年   50篇
  2002年   40篇
  2001年   38篇
  2000年   51篇
  1999年   29篇
  1998年   23篇
  1997年   21篇
  1996年   13篇
  1995年   12篇
  1994年   13篇
  1993年   20篇
  1992年   20篇
  1991年   37篇
  1990年   24篇
  1989年   26篇
  1988年   22篇
  1987年   31篇
  1986年   25篇
  1985年   16篇
  1984年   18篇
  1983年   18篇
  1982年   9篇
  1981年   13篇
  1980年   14篇
  1979年   21篇
  1978年   11篇
  1977年   8篇
  1976年   7篇
  1975年   9篇
  1974年   15篇
  1973年   11篇
  1969年   6篇
排序方式: 共有1212条查询结果,搜索用时 62 毫秒
81.
We compared the pulsatile secretion of luteinizing hormone (LH) between 13 men with clinically and electrographically documented temporal lobe seizures and 8 age-matched controls. Serum for LH measurement was drawn every 15 minutes during 8 hours of EEG telemetry in both groups. The 2 groups did not differ significantly in average mean baseline LH secretion, total LH secretion, or average pulse amplitude. The group with seizures, however, showed a significantly greater (p less than 0.05) variability of baseline LH secretion and pulse frequency. Among the men with unilateral paroxysmal EEG findings, pulse frequency was significantly greater (p = 0.05) with right epileptiform discharges or left slowing (6.4 +/- 0.4) than with left epileptiform discharges or right slowing (3.0 +/- 1.3). The relationship of pulse frequency to the nature and laterality of paroxysmal discharges makes it unlikely that endocrine abnormalities can be attributed to medication alone and strengthens the notion that temporal lobe epileptiform discharges may disrupt hypothalamic regulation of pituitary secretion.  相似文献   
82.
BACKGROUND: Acute graft versus host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. Preclinical studies have suggested that a T-cell subset with a CD4-/CD8- double-negative (DN) T-cell phenotype is capable of suppressing GVHD. Double-negative T cells can be mobilized into the peripheral blood with granulocyte colony-stimulating factor (G-CSF) and enriched by density centrifugation. The current study was performed to study the feasibility and safety of applying a density gradient separation technique for enrichment of CD34+ and DN T cells, while depleting CD4+ and CD8+ single-positive (SP) T cells from peripheral blood progenitor cells (PBPCs) for the purpose of allogeneic transplantation. METHODS: Twenty-five patients with advanced hematologic malignancies were treated with a myeloablative preparative regimen consisting of fractionated total body irradiation, etoposide, and cyclophosphamide. Human leukocyte antigen identical donors were mobilized with G-CSF PBPC collected by apheresis. The apheresis product was applied to a single-step density gradient, and the low-density cell population was collected. The low-density cell population was infused as the sole source of allogeneic cells after myeloablative therapy. Graft versus host disease prophylaxis consisted of cyclosporine with or without prednisone. RESULTS: CD34 cell recovery was efficient with a median 72% yield, providing for a median CD34+ cell dose of 6.5 x 10(6)/kg (range,1.0- 13.9 x 10(6)/kg). CD3+CD4+ or CD3+CD8+ SP T cells were depleted by a median of 94.4% (range, 58.8- 99.2%), and the ratio of CD34+:SP T cells increased 10-fold. Double-negative T cells were depleted by 92% (range, 18.8- 99.4%), thus the ratio of DN:SP T cells increased less than 2-fold in 71% of apheresis samples tested. Hematopoietic engraftment was rapid, and there was no occurrence of graft failure in examinable patients. Median time to absolute neutrophil count greater than 0.5 x 10(9)/L and platelet count greater than 20 x 10(9)/L was 10.5 and 12 days, respectively. The incidence of Grade 2-4 acute GVHD was 26% (95% confidence interval [CI], 6-45%), although not all patients were examinable due to an unexpectedly high nonrecurrence mortality that at Day 180 was 62% (95% CI, 40-83%). CONCLUSIONS: These data suggest that T-cell subset manipulation via density gradient separation is a safe procedure and allowed rapid hematopoietic recovery. Selective enrichment of a donor DN T-cell subset was observed in only a few and was not associated with a reduced incidence of GVHD. However, the low-density selected cells still resulted in GVHD, and there was a high treatment-related mortality.  相似文献   
83.
Zusammenfassung Es wird eine neue Versuchsanordnung angegeben, die das Atemvolumen kleiner Versuchstiere, wie Mäuse, Ratten und Meerschweinchen, durch die Bewegung von Aluminiumhüpfern in Präzisionsglasrohren zu bestimmen gestattet.Die Bewegungen der hüpfenden Marken können durch eine besondere Anordnung photographisch registriert werden.Nach Eichung der Glasrohre durch eine Eichapparatur ist es möglich, das Atemvolumen der genannten Versuchstiere bis auf 0,1 bzw. 0,01 ccm genau zu bestimmen.Die photographische Registrierung gibt auch ein Bild von der durchschnittlichen Sauggeschwindigkeit.Mit 10 Textabbildungen.  相似文献   
84.
A review of 162 patients with Hodgkin disease disclosed 36 with microcytic anemia (mean corpuscular hemoglobin values [MCV] less than 80 fl). Three patients had iron deficiency, and one had beta-thalassemia. Of the remaining 32 patients, 24 had microcytic anemia at the time of diagnosis of Hodgkin disease, and ten, including two patients with this finding initially, developed microcytic anemia in association with recurrence of Hodgkin disease. Seven patients with Hodgkin disease and normal MCV had normal alpha-to-beta-globin chain ratios (1.0 +/- 0.14). Seven patients with Hodgkin disease and MCV less than 80 fl had significantly lower alpha-to-beta chain ratios (0.66 +/- 0.05). Twelve normal controls and four with iron-deficiency anemia and MCV less than 80 fl had normal ratios. Anemia was corrected, and MCV returned to normal in all patients who responded to therapy for Hodgkin disease. In the two patients studied sequentially, abnormal alpha-to-beta-chain ratio was corrected along with the anemia.  相似文献   
85.
The absorption of three combination formulations of hydrochlorothiazide and either triamterene or amiloride was studied over a 5-year period in seven separate investigations under varying conditions of food and fasting. The most widely prescribed combination, containing 25 mg of hydrochlorothiazide and 50 mg of triamterene, demonstrated impaired absorption in the fasting state that was partially corrected by the addition of a breakfast high in fat. The increase in the fat content of the food appeared to correlate directly with the amount of both drugs absorbed from this formulation. The second formulation studied, a new combination formulation of 50 mg of hydrochlorothiazide and 75 mg of triamterene, demonstrated acceptable absorption in the fasting state that was not altered by the concurrent administration of a high-fat breakfast. The absorption of the third formulation, a combination of 50 mg hydrochlorothiazide and 5 mg amiloride, was acceptable in the fasting state and demonstrated a slight reduction in the absorption of the amiloride component when administered concurrently with a high-fat meal. The clinical and biopharmaceutic implications of these observations are discussed.  相似文献   
86.
87.
88.
对人流感病毒A/Udorn/72(H_3N_2)株与禽类流感病毒A/Mallard/NY/78/(H_2N_2)重组后的重组株分析表明,仅含禽类病毒的核蛋白(NP)或膜蛋白(M)的RNA片段的重组株,在松鼠猴的呼吸道繁殖是受限制的。另外。仅有禽类的RNAl和NS基因的重组株(Clone 12)在松鼠猴的气管内的繁殖也明显受限制,而只具有其中一个基因的Clone 9, Clone 2, 则限制就不明显。由此表明,禽类流感病毒的NP和M基因在宿主范围的繁殖限制中起主要作用,而RNAI和SN基因的结合,同样起着繁殖受限制作用。  相似文献   
89.
Shark Infested Seas   总被引:2,自引:2,他引:0  
  相似文献   
90.
狼疮样综合征和抗中性粒细胞胞浆抗体(ANCA)阳性的血管炎合并甲亢在临床中十分罕见.为了找出这三种疾病之间的关系,作者借助循证医学的方法,根据患者病情,提出临床问题,从PubMed(1966~2003年)、中国生物医学文献数据库(CBM)(1978~2003年)、荷兰医学文摘数据库(EMBase)(1974~2003年)查找相关信息.结果发现抗甲状腺药物的副反应是对该病例的最好解释,并据此采取了相应治疗措施,使患者病情获得明显好转.  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