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   650篇
  免费   37篇
  国内免费   20篇
耳鼻咽喉   2篇
儿科学   28篇
妇产科学   7篇
基础医学   45篇
口腔科学   26篇
临床医学   138篇
内科学   144篇
皮肤病学   2篇
神经病学   9篇
特种医学   157篇
外科学   44篇
综合类   24篇
预防医学   25篇
药学   23篇
肿瘤学   33篇
  2023年   6篇
  2022年   2篇
  2021年   10篇
  2020年   2篇
  2019年   4篇
  2018年   5篇
  2017年   6篇
  2016年   9篇
  2015年   5篇
  2014年   15篇
  2013年   24篇
  2012年   15篇
  2011年   16篇
  2010年   26篇
  2009年   44篇
  2008年   16篇
  2007年   16篇
  2006年   8篇
  2005年   14篇
  2004年   4篇
  2003年   11篇
  2002年   11篇
  2001年   12篇
  2000年   14篇
  1999年   10篇
  1998年   40篇
  1997年   38篇
  1996年   37篇
  1995年   35篇
  1994年   22篇
  1993年   25篇
  1992年   7篇
  1991年   5篇
  1990年   8篇
  1989年   25篇
  1988年   24篇
  1987年   15篇
  1986年   9篇
  1985年   16篇
  1984年   10篇
  1983年   8篇
  1982年   19篇
  1981年   12篇
  1980年   17篇
  1979年   1篇
  1978年   8篇
  1977年   12篇
  1976年   7篇
  1975年   2篇
排序方式: 共有707条查询结果,搜索用时 203 毫秒
81.
82.
Weinberg  JB; Sauls  DL; Misukonis  MA; Shugars  DC 《Blood》1995,86(4):1281-1287
  相似文献   
83.
Heaton  DC; Fitzgerald  PH; Fraser  GJ; Abbott  GD 《Blood》1981,57(5):883-887
A newborn without any signs of Down's syndrome was found to have an acute proliferation that remitted without drug therapy. Chromosomal analysis of blood, bone marrow, and skin cells revealed that the child was a constitutional mosaic with normal cells and a low number of cells in which one no. 21 chromosome was replaced by a probably isochromosome for the no. 21 long arm: 46,XY/46,XY,i(21q). The abnormal cell line of the mosaic appeared to be selectively involved in this proliferation.  相似文献   
84.
Price  TH; Chatta  GS; Dale  DC 《Blood》1996,88(1):335-340
Recombinant granulocyte colony-stimulating factor (G-CSF) was administered to healthy young (n = 32) and elderly (n = 19) volunteers (0 microgram/d, 30 microgram/d, or 300 microgram/d) to determine its effect on neutrophil production, blood kinetics, and tissue migration. Measurements included blood counts (daily), marrow neutrophil pool sizes and neutrophil tissue migration (baseline and day 5), blood kinetics (day 6), and marrow transit time while on drug (days 6 to 14). G-CSF markedly expanded the marrow neutrophil mitotic pool and shortened the transit time of the postmitotic pool (control, mean = 6.4 days; 300 microgram/d, mean = 2.9 d). G-CSF increased neutrophil production without significantly altering blood neutrophil half-life or margination. Compared to control, neutrophil accumulation in skin chambers decreased by about 50% in the 300 microgram/d group in both young and elderly subjects. G-CSF induced neutrophilia by stimulating proliferation of marrow neutrophil precursors and accelerating neutrophil entry into the blood. Decreased neutrophil inflammatory responses measured with the skin chamber technique may be because of the relative immaturity of the circulating cells or to alterations in neutrophil phenotype induced by G-CSF.  相似文献   
85.
From 1990 to 1993 we performed a prospective study of busulfan (16 mg/kg) and cyclophosphamide (120 mg/kg) in 30 patients with refractory anemia (RA) undergoing related (n = 17) or unrelated (n = 13) donor marrow transplantation. Nineteen patients survive disease free (63% 3- year actuarial disease-free survival [DFS]) and no patient relapsed. These results were compared to those of 38 historical controls with RA treated with cyclophosphamide and total body irradiation, of whom 22 are disease-free survivors and 1 relapsed. After correcting for significant variables between the two treatment groups, we found no statistically significant difference in outcome based on preparative regimen. Combining data from these 68 patients plus 2 additional patients with RA treated before 1993 with busulfan and cyclophosphamide, we identified four variables independently associated with improved survival: younger age, shorter disease duration, lower neutrophil count pretransplant, and lower hematocrit pretransplant. We also found that 15 patients 40 to 55 years of age had a 46% 3-year actuarial DFS and 26 patients receiving unrelated or mismatched related donor marrow had a 50% 3-year actuarial DFS. We conclude that there does not appear to be any significant difference in outcome based on preparative regimen in this patient population. In addition, allogeneic bone marrow transplantation may be a reasonable approach to therapy of RA early after diagnosis. However, whether early intervention with transplantation prolongs survival over that expected without transplantation cannot be ascertained with certainty from available data.  相似文献   
86.
大肠癌免疫组化表达与临床病理的关系   总被引:1,自引:0,他引:1  
目的:探讨大肠癌CEA、P53、nm23、Ki-67、MRP免疫组化表达特点和相互关系,及其与临床病理的关系.方法:回顾性分析2003-01/2006-07我院收治的73例大肠癌患者的临床病理及随访资料,并对其石蜡标本采用免疫组化SP染色法检测CEA、P53、nm23、Ki-67、MRP,分析其免疫组化特点及其与临床病理之间的关系.结果:CEA、P53、nm23、Ki-67、MRP在大肠癌中的阳性表达率依次为82.2%、68.5%、75.3%、84.9%和64.4%.CEA、MRP与大肠癌患者的各因素无统计学差异.P53、Ki-67和nm23与肿瘤的Dukes分期和淋巴结转移有关, P53、Ki-67在Dukes C、D期的阳性表达率(依次为82.8%和100%1明显高于Dukes A、B期者(59.1%和75.0%)(P<0.05),而nm23在Dukes C、D期的阳性表达率(58.6%)明显低于Dukes A、B期者(86.4%)(P<0.05).CEA与nm23的表达呈明显的负相关(r=-0.296,P=0.011),而P53和Ki-67表达之间呈现明显的正相关(r= 0.308,P=0.008),其他各指标间的表达无相关性.nm23、P53和Ki-67与预后因素关系明显,nm23在生存期≥3 a患者的阳性表达率(92.9%)高于生存期<3 a者(71.2%)(P<0.05),而P53和Ki-67在生存期≥3 a患者的阳性表达率(依次为42.9%和64.3%)明显低于生存期<3 a者(74.6%和89.8%)(P<0.05).结论:P53、Ki-67和nm23的表达与大肠癌的侵袭转移和预后密切相关.CEA可能是大肠癌的侵袭转移的促进因素.MRP所引起的耐药机制是一个相对独立的机制.CEA、P53、nm23、Ki-67可作为判断大肠癌恶性程度、侵袭转移以及预后的指标.  相似文献   
87.
Immunologic heterogeneity of diffuse large cell lymphoma   总被引:2,自引:0,他引:2  
The cellular lineage of 57 diffuse large-cell lymphomas (DLCLs) was determined using a panel of monoclonal antibodies directed against lineage-restricted and -associated T, B, and monocyte antigens. The majority (82%) were of B cell lineage as determined by the expression of sig and/or B1, with the remaining 16% being of T cell lineage and 2%, of monocyte-myeloid lineage. By the expression of other B cell- restricted and -associated antigens, two major and two minor subgroups could be identified. These subgroups expressed the following phenotypes: (1) B1+B4+sIG+B2- (51%); (2) B1+B4+sIg+B2+ (29%); (3) B1+B4+sIg-B2+ (10%); and (4) B1+B4-sIg+B2- (10)%. The morphology of transformed lymphocytes, the weak to absent expression of the early B cell antigens B2 and sIgD, and the absence of the late B cell differentiation antigens PCA-1 and PC-1 suggested that these tumors were the neoplastic counterparts of normal B cells at the mid-stages of differentiation. Further support for the notion that B-DLCLs correspond to transformed B lymphocytes was concluded from the observation that B cells could be identified in normal spleen that expressed the cell surface phenotype and morphological appearance of the majority of B- DLCLs.  相似文献   
88.
In an attempt to decrease the relapse rate after bone marrow transplantation (BMT) for advanced acute leukemia, we initiated studies using 131I-labeled anti-CD45 antibody (BC8) to deliver radiation specifically to hematopoietic tissues, followed by a standard transplant preparative regimen. Biodistribution studies were performed in 23 patients using 0.5 mg/kg trace 131I-labeled BC8 antibody. The BC8 antibody was cleared rapidly from plasma with an initial disappearance half-time of 1.5 +/- 0.2 hours, presumably reflecting rapid antigen- specific binding. The mean radiation absorbed doses (cGy/mCi131I administered) were as follows: marrow, 7.1 +/- 0.8; spleen, 10.8 +/- 1.4; liver, 2.7 +/- 0.2; lungs, 2.1 +/- 0.1; kidneys, 0.7 +/- 0.1; and total body, 0.4 +/- 0.03. Patients with acute myelogenous leukemia (AML) in relapse had a higher marrow dose (11.4 cGy/mCi) than those in remission (5.2 cGy/mCi; P = .001) because of higher uptake and longer retention of radionuclide in marrow. Twenty patients were treated with a dose of 131I estimated to deliver 3.5 Gy (level 1) to 7 Gy (level 3) to liver, with marrow doses of 4 to 30 Gy and spleen doses of 7 to 60 Gy, followed by 120 mg/kg cyclophosphamide (CY) and 12 Gy total body irradiation (TBI). Nine of 13 patients with AML or refractory anemia with excess blasts (RAEB) and two of seven with acute lymphocytic leukemia (ALL) are alive disease-free at 8 to 41 months (median, 17 months) after BMT. Toxicity has not been measurably greater than that of CY/TBI alone, and the maximum tolerated dose has not been reached. This study demonstrates that with the use of 131I-BC8 substantially greater doses of radiation can be delivered to hematopoietic tissues as compared with liver, lung, or kidney, which may improve the efficacy of marrow transplantation.  相似文献   
89.
Studies of circulating hemopoietic progenitor cells in human fetal blood   总被引:3,自引:0,他引:3  
Linch  DC; Knott  LJ; Rodeck  CH; Huehns  ER 《Blood》1982,59(5):976-979
High levels of committed erythroid and granulocytic/monocytic progenitor cells have been demonstrated in fresh blood obtained at fetoscopy. The fetal progenitor cells were more sensitive to appropriate stimuli (erythropoietin and colony-stimulating factor) than adult progenitor cells grown under the same conditions, and this was shown to be due to intrinsic differences in the progenitor cells at the different developmental stages.  相似文献   
90.

Purpose

Vascular endothelial growth factor (VEGF) is the most potent stimulator of angiogenesis. The aim of this study was to evaluate the role of serum VEGF as a diagnostic, predictive and prognostic marker in Ewing’s sarcoma.

Methods

Patients with histopathologically proven diagnosis of Ewing’s sarcoma without prior chemotherapy or radiotherapy were invited to take part in the study. Pre-chemotherapy, post-chemotherapy and post-surgery blood samples were collected for analysis of serum VEGF levels. Blood samples from ten sex- and age-matched healthy volunteers were collected for estimation of VEGF levels to act as control. Human VEGF Elisa kit (Bender Medsystem, Austria) was used to assess the serum VEGF levels.

Results

A total of nine cases of Ewing’s sarcoma were included in the study. Mean age in the group was 12.44 years (range, seven to 18 years). Mean and median serums VEGF level in the study population were 4,547.78 pg/ml and 3,780.00 pg/ml, respectively. Ten age- and sex-matched healthy volunteers were selected as controls. No significant correlation was obtained between serum VEGF, age, sex and tumour size. Mean serum VEGF was significantly raised in the study group as compared to controls (p = 0.001). We observed a significant decline in serum VEGF level following neoadjuvant chemotherapy (p = 0.008). No correlation could be established between serum VEGF level pulmonary metastasis and overall survival.

Conclusion

Serum VEGF might have a role as a diagnostic and predictive marker in patients with Ewing’s sarcoma.  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