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   989篇
  免费   47篇
  国内免费   32篇
儿科学   14篇
妇产科学   15篇
基础医学   96篇
口腔科学   18篇
临床医学   90篇
内科学   129篇
皮肤病学   128篇
神经病学   32篇
特种医学   133篇
外科学   137篇
综合类   93篇
预防医学   26篇
眼科学   4篇
药学   74篇
肿瘤学   79篇
  2021年   11篇
  2019年   10篇
  2018年   5篇
  2017年   11篇
  2016年   13篇
  2015年   19篇
  2014年   16篇
  2013年   26篇
  2012年   34篇
  2011年   31篇
  2010年   19篇
  2009年   25篇
  2008年   39篇
  2007年   52篇
  2006年   37篇
  2005年   36篇
  2004年   27篇
  2003年   24篇
  2002年   28篇
  2001年   27篇
  2000年   33篇
  1999年   33篇
  1998年   44篇
  1997年   31篇
  1996年   23篇
  1995年   22篇
  1994年   20篇
  1993年   16篇
  1992年   9篇
  1991年   23篇
  1990年   15篇
  1989年   17篇
  1988年   23篇
  1987年   23篇
  1986年   25篇
  1985年   18篇
  1984年   20篇
  1983年   16篇
  1982年   15篇
  1981年   16篇
  1980年   14篇
  1979年   15篇
  1978年   16篇
  1977年   5篇
  1975年   15篇
  1974年   5篇
  1971年   4篇
  1968年   4篇
  1966年   6篇
  1919年   4篇
排序方式: 共有1068条查询结果,搜索用时 15 毫秒
101.
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   
102.
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   
103.
A monoclonal antibody, designated BM-1, which is reactive in B5 formalin-fixed, paraffin-embedded tissues, has been generated against a cytoplasmic and nuclear antigen expressed in human myeloid precursor cells and derived leukemias. Using the avidin-biotin-complex immunoperoxidase procedure, BM-1 was found to stain selectively myeloid precursor cells in normal bone marrow and mature granulocytes in the blood. In a screen of 26 normal adult and fetal human organs fixed in B5 formalin, BM-1 was negative in all nonhematopoietic tissues with the exception of tissue granulocytes and scattered cells in the peripheral cortex of the thymus. Likewise a screen of 30 solid tumor cell lines including a spectrum of carcinomas, sarcomas, and neural-derived tumors was negative. BM-1 was also negative with 21 T and B cell lymphomas and 11 Hodgkin's disease tumors. A preliminary study of tumors of the hematopoietic system revealed that BM-1 was reactive with M2 and M3 acute myelogenous leukemias (AML), chronic myelogenous leukemias (CML) and myelomonocytic leukemias, and granulocytic sarcomas. M1, M4, M5, and M6 AML clot preparations were negative in this study, indicating that BM-1 may have a role in the histopathologic diagnosis of myelogenous leukemia. Myeloid leukemic cell lines HL-60, ML-2, KG1, and TPH-1-O showed BM-1 nuclear and/or cytoplasmic reactivity in a subpopulation of cells, but erythroid and lymphoid leukemias and all lymphoma cell lines were negative. Immunoperoxidase studies of a panel of fetal tissues showed BM-1 positive cells in the peripheral cortex of the thymus and portal myelopoietic regions of the liver at 18 weeks gestation. Finally, DNA-cellulose and solid phase radioimmunoassay (RIA) techniques developed in our laboratory demonstrate that the BM-1 antigenic domain is reactive only after binding to eukaryotic but not prokaryotic single- or double-stranded DNA. Immunoblot techniques using a DNA-cellulose purified protein sample revealed that BM-1 recognizes a 183 kD protein. These studies indicate that BM-1 is recognizing a myeloid-specific antigen that, because of its DNA binding characteristics, may have an important role in the differentiation of myeloid cells at the molecular level.  相似文献   
104.
105.
106.
All surviving patients between 18 and 88 years of age receiving biological or mechanical prosthetic heart valves at the Yale-New Haven Hospital from January 1974 through January 1985 were analyzed for thromboembolism, anticoagulation-related hemorrhage, endocarditis, perivalvular leak, valve failure, need for reoperation, late cardiac death, and valve-related death. The rates of these events were analyzed in linear and actuarial terms over the 11 year period. A total of 533 patients received 606 biological valves (328 aortic, 252 mitral, 24 tricuspid, and two pulmonary, consisting of 482 Carpentier-Edwards, 108 Hancock, 15 Ionescu-Shiley, and one other), with a mean follow-up of 2,571 patient-years and 2,935 valve-years. They were compared with 479 patients with 510 mechanical valves (330 aortic, 175 mitral, and five tricuspid, consisting of 178 Starr-Edwards, 166 St. Jude Medical, 164 Bj?rk-Shiley, and two others), which were implanted for 2,247 patient-years and 2,392 valve-years. We found a significantly increased incidence of thromboembolism (p less than 0.001) and reoperation for perivalvular leak (p less than 0.05) in the mechanical valves compared with the biological valves, but a significantly increased rate of valve failure (p less than 0.001) in the biological valves compared with the mechanical valves. The overall analysis comparing total morbidity and valve-related mortality significantly (p less than 0.01) favored the biological valves in the first 5 years of the study and the mechanical valves (p less than 0.001) in the second 5 years of the study. However, the net 10 year results showed no significant difference between the two types of valves. In summary, we found little direct evidence to strongly support the generalized use of one type of valve over another.  相似文献   
107.
108.
109.
110.
Zusammenfassung Grundlagen: Ergotaminpr?parate werden nach wie vor zur Coupierung des akuten Migr?neanfalls eingesetzt. Bei der Anwendung von ergotaminhaltigen Suppositorien k?nnen lokale perianale und rektale Ulzerationen entstehen. Methodik: Wir berichten über eine 39j?hrige Patientin mit einer ergotamininduzierten rektovaginalen Fistel. Ergebnisse: Je nach H?he und Durchmesser der Fistel k?nnen unterschiedliche Verfahren zur chirurgischen Sanierung gew?hlt werden. Bei unserer Patientin haben wir nach Anlage eines Anus praeter transversalis eine transvaginale Exzision mit Schichtverschlu? erfolgreich durchgeführt. Schlu?folgerungen: Der anorektale Ergotismus ist wegen des h?ufig verschweiegenen Abusus und der ungew?hnlichen Manifestation bisher selten diagnostiziert worden.   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