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   764篇
  免费   39篇
  国内免费   20篇
耳鼻咽喉   4篇
儿科学   28篇
妇产科学   10篇
基础医学   53篇
口腔科学   31篇
临床医学   147篇
内科学   166篇
皮肤病学   16篇
神经病学   14篇
特种医学   163篇
外科学   47篇
综合类   31篇
预防医学   31篇
眼科学   1篇
药学   46篇
肿瘤学   35篇
  2023年   6篇
  2021年   10篇
  2017年   7篇
  2016年   9篇
  2015年   5篇
  2014年   15篇
  2013年   26篇
  2012年   10篇
  2011年   16篇
  2010年   24篇
  2009年   46篇
  2008年   15篇
  2007年   15篇
  2006年   8篇
  2005年   13篇
  2003年   10篇
  2002年   11篇
  2001年   12篇
  2000年   14篇
  1999年   10篇
  1998年   40篇
  1997年   40篇
  1996年   41篇
  1995年   36篇
  1994年   24篇
  1993年   31篇
  1992年   9篇
  1991年   5篇
  1990年   11篇
  1989年   29篇
  1988年   28篇
  1987年   17篇
  1986年   9篇
  1985年   18篇
  1984年   12篇
  1983年   9篇
  1982年   21篇
  1981年   15篇
  1980年   19篇
  1978年   9篇
  1977年   12篇
  1976年   7篇
  1959年   6篇
  1958年   9篇
  1957年   8篇
  1956年   8篇
  1955年   12篇
  1954年   8篇
  1949年   5篇
  1948年   6篇
排序方式: 共有823条查询结果,搜索用时 0 毫秒
71.
BULL  BRIAN S.; KUHN  IRVIN N. 《Blood》1970,35(1):104-111
The relationship between intravascular coagulation and schistocyte formation has been adequately documented in animal experiments and in in vitromodels. A case report is presented of a patient who suffered from micro-angiopathic hemolytic anemia during life as a result of disseminated gastricadenocarcinoma. The fibrin microclots found in his vasculature on postmortemexamination indicate that in intravascular coagulation, both in the human andin the experimental animal, fibrin initially polymerizes in the form of finefibrin strands. These strands, the main etiologic factor in producing schistocytes, are constantly being lysed or rendered amorphous, and rarely persistin postmortem tissues except under unusually favorable conditions. Postmortem histologic study of one case where such favorable conditions didexist indicates the essential identity of the pathologic process in man and inexperimental animals.

Submitted on May 26, 1969 Accepted on July 22, 1969  相似文献   
72.
73.
Weinberg  JB; Sauls  DL; Misukonis  MA; Shugars  DC 《Blood》1995,86(4):1281-1287
  相似文献   
74.
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   
75.
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   
76.
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   
77.
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   
78.
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   
79.

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   
80.
BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. METHODS: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis.  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