全文获取类型
收费全文 | 1033篇 |
免费 | 42篇 |
国内免费 | 37篇 |
专业分类
儿科学 | 36篇 |
妇产科学 | 28篇 |
基础医学 | 58篇 |
口腔科学 | 34篇 |
临床医学 | 471篇 |
内科学 | 113篇 |
皮肤病学 | 6篇 |
神经病学 | 46篇 |
特种医学 | 114篇 |
外科学 | 31篇 |
综合类 | 26篇 |
预防医学 | 44篇 |
眼科学 | 7篇 |
药学 | 45篇 |
肿瘤学 | 53篇 |
出版年
2023年 | 5篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 17篇 |
2014年 | 17篇 |
2013年 | 36篇 |
2012年 | 14篇 |
2011年 | 6篇 |
2010年 | 27篇 |
2009年 | 35篇 |
2008年 | 21篇 |
2007年 | 30篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 24篇 |
2003年 | 21篇 |
2002年 | 26篇 |
2001年 | 37篇 |
2000年 | 25篇 |
1999年 | 37篇 |
1998年 | 92篇 |
1997年 | 86篇 |
1996年 | 80篇 |
1995年 | 66篇 |
1994年 | 50篇 |
1993年 | 56篇 |
1992年 | 19篇 |
1991年 | 26篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 34篇 |
1987年 | 11篇 |
1986年 | 14篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1971年 | 2篇 |
1962年 | 1篇 |
1958年 | 2篇 |
排序方式: 共有1112条查询结果,搜索用时 15 毫秒
31.
32.
Interleukin-1 alpha (IL-1 alpha) is a macrophage-derived, multifunctional cytokine that broadly potentiates myelopoiesis and induces the synthesis of hematopoietic colony-stimulating factors (CSF) in vitro and in vivo. To evaluate the possibility for use of IL-1 alpha in ameliorating in vivo bone marrow suppression induced by drugs or radiation, we examined the in vivo effects of the cytokine on erythropoietic and other hematopoietic progenitor cells. Normal mice were treated with a single intraperitoneal (IP) injection of recombinant human IL-1 alpha at varying doses and were assayed at various times post-treatment. By six hours postinjection, a significant suppression of mature erythroid progenitors (CFU-E) was observed in animals treated with IL-1 alpha (0.5 micrograms/mouse), with maximum suppression of CFU-E and peripheral blood reticulocyte counts occurring at 24 hours. Decreases in peripheral blood hematocrit did not occur after a single IL-1 alpha injection but were observed after multiple injections of the cytokine. The suppressive effects of IL-1 alpha on late-stage erythropoiesis were abrogated by simultaneous administration of erythropoietin (EPO). At 48 hours post-treatment, a marked stimulation was observed in the numbers of spleen and marrow immature erythroid (BFU-E), macrophage (CFU-M), granulocyte (CFU-G), granulocyte- macrophage (CFU-GM), and megakaryocyte (CFU-meg) progenitor cells. These results demonstrate the potential use of IL-1 alpha as a generalized stimulator of hematopoiesis and show that the cytokine- induced suppression of late-stage erythropoiesis can be prevented by EPO. 相似文献
33.
Dr. Robert H. Thorlakson M.D.; F.R.C.S. F.R.C.S.C. F.A.CS. 《Diseases of the colon and rectum》1986,29(9):591-593
A set of double-angled needle holders and long, angled tissue forceps have been designed and presented for use in surgery
of the abdomen. The problems of passage and control of curved needles in all directions is well recognized. The marriage of
design and presentation addresses the mechanical and anatomic needs of surgeons in the pelvis, subdiaphragmatic area, and
in large and obese patients. Multiple variables in use provided by these instruments, particularly when used together, enhance
surgical control at problem sites. 相似文献
34.
Influence of oxygen tension on the viscoelastic behavior of red blood cells in sickle cell disease 总被引:2,自引:0,他引:2
Although the rheological behavior of sickle cell suspensions and of hemoglobin S solutions is known to be strongly dependent on oxygen tension (PO2), little data exist concerning the influence of PO2 on the viscoelasticity of individual HbSS RBC. We have used micropipette aspiration techniques to test the deformation response of both HbSS and control HbAA RBC over a wide range of PO2 at 23 degrees C. Sickled, spiculed HbSS cells were present for PO2 approximately less than 35 mm Hg; for a number of these cells, the deformation response was essentially elastic and an effective membrane rigidity (EMR) was calculated. EMR increased with decreasing PO2 and was approximately 5 to 50 times higher than the equivalent rigidity of oxygenated HbSS RBC. In addition, the rate of membrane deformation was very slow for sickled cells; the half-time for the deformation process increased as PO2 was lowered and was about two orders of magnitude longer than the equivalent time for normal RBC. Other sickled cells exhibited plastic deformation when subjected to comparable deforming forces and experienced irreversible membrane deformation and budding. At all PO2 levels tested, some HbSS RBC remained as discocytes; these cells had normal membrane elasticity and membrane viscosity. Furthermore, changes in PO2 did not affect the membrane properties of HbAA RBC. Thus, gross abnormalities in the deformation response of HbSS RBC were only detected after morphological sickling had occurred. These abnormalities most likely arose from changes in the cytoplasmic HbS viscoelasticity and, if present in vivo, would be expected to impair the flow of HbSS cells in the microcirculation. 相似文献
35.
Alloimmunization to platelets in heavily transfused patients with sickle cell disease 总被引:2,自引:0,他引:2
Bone marrow transplantation (BMT) is now an option for some patients with sickle cell disease (SCD). Many SCD patients are multiply transfused with red blood cells (RBCs), and may be immunized to alloantigens other than erythrocyte antigens. Because platelet refractoriness is a significant complication during BMT, we wished to determine the prevalence of alloimmunization to platelets in transfused SCD patients. Sera collected from 47 transfused and 14 untransfused SCD patients were screened for HLA and platelet-specific antibodies. Transfusion and RBC antibody histories were reviewed. A subset of the patients were rescreened 1 year later. Eighty-five percent of patients with at least 50 RBC transfusions (22 of 26), 48% of patients with less than 50 transfusions (10 of 21), and none of 14 untransfused patients demonstrated platelet alloimmunization (P < .05). Platelet alloimmunization was more prevalent than RBC alloimmunization (20% to 30%). Half of the platelet reactivity was chloroquine-elutable. Eighteen of 22 patients (82%) on chronic RBC transfusion remained platelet-alloimmunized 11 to 22 months after initial testing. In summary, 85% of heavily transfused SCD patients are alloimmunized to HLA and/or platelet-specific antigens. These patients may be refractory to platelet transfusion, a condition that would increase their risk during BMT. Leukodepletion in the transfusion support of SCD patients should be considered to prevent platelet alloimmunization. 相似文献
36.
37.
Simone CS Wolfkamp Caroline Verseyden Esther WM Vogels Sander Meisner Kirsten Boonstra Charlotte P Peters Pieter CF Stokkers Anje A te Velde 《World journal of gastroenterology : WJG》2014,20(10):2664-2672
AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease. 相似文献
38.
Jay R Shapiro Caressa Lietman Monica Grover James T Lu Sandesh CS Nagamani Brian C Dawson Dustin M Baldridge Matthew N Bainbridge Dan H Cohn Maria Blazo Timothy T Roberts Feng‐Shu Brennen Yimei Wu Richard A Gibbs Pamela Melvin Philippe M Campeau Brendan H Lee 《Journal of bone and mineral research》2013,28(7):1523-1530
39.
40.
Provision of childhood primary care services and differences between types of providers (family practice physicians, pediatricians, nurse practitioners, and physicians' assistants) were explored in this study. A mail survey was conducted in Wyoming using a questionnaire based on the recommendations from the U. S. Preventive Service Task Force. Sixty-one percent of the providers returned questionnaires. While some areas of assessment, screening, and treatment/counseling services were provided at high levels, many were not. Gaps exist particularly in the areas of behavioral and lifestyle assessment and treatment/counseling. Only small differences existed between types of providers. However, nurse practitioners and pediatricians were more likely to report that they followed recommendations, while physicians' assistants were least likely to report that they followed recommendations. 相似文献