全文获取类型
收费全文 | 738篇 |
免费 | 28篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 39篇 |
妇产科学 | 3篇 |
基础医学 | 61篇 |
口腔科学 | 11篇 |
临床医学 | 96篇 |
内科学 | 212篇 |
皮肤病学 | 20篇 |
神经病学 | 75篇 |
特种医学 | 144篇 |
外科学 | 24篇 |
综合类 | 24篇 |
预防医学 | 9篇 |
眼科学 | 5篇 |
药学 | 55篇 |
中国医学 | 3篇 |
肿瘤学 | 30篇 |
出版年
2023年 | 2篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 22篇 |
2014年 | 18篇 |
2013年 | 22篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 31篇 |
2009年 | 27篇 |
2008年 | 14篇 |
2007年 | 54篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 5篇 |
2002年 | 18篇 |
2001年 | 19篇 |
2000年 | 7篇 |
1999年 | 13篇 |
1998年 | 45篇 |
1997年 | 47篇 |
1996年 | 56篇 |
1995年 | 31篇 |
1994年 | 32篇 |
1993年 | 20篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 33篇 |
1988年 | 27篇 |
1987年 | 21篇 |
1986年 | 21篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 6篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1931年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有813条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Batard P; Sansilvestri P; Scheinecker C; Knapp W; Debili N; Vainchenker W; Buhring HJ; Monier MN; Kukk E; Partanen J; Matikainen MT; Alitalo R; Hatzfeld J; Alitalo K 《Blood》1996,87(6):2212-2220
Growth factor receptors in human hematopoietic progenitor cells have become the focus of intense interest, because they may provide tools for the monitoring, enrichment, and expansion of stem cells. We have shown earlier that the Tie receptor tyrosine kinase is expressed in erythroid and megakaryoblastic human leukemia cell lines, in the blood islands of the yolk sac, and in endothelial cells starting from day 8.0 of mouse development. Here, the expression of Tie was studied in human hematopoietic cells of various sources. Peripheral blood mononuclear cells were Tie-. However, a large fraction of CD34+ cells from umbilical cord blood (UCB) and bone marrow (BM) expressed tie protein and mRNA. On average, 64% of the fluorescence-activated cell sorting- gated UCB CD34+ cells including CD38- cells and a fraction of cells expressing low levels of c-Kit were Tie+. Also, 30% to 60% of BM CD34+ cells were Tie+, including most of the BM CD34+CD38-, CD34+Thy-1+, and CD34+HLA-DR- cells. Under culture conditions allowing myeloid, erythroid, and/or megakaryocytic differentiation, purified UCB CD34+ cells lost Tie mRNA and protein expression concomitantly with that of CD34; however, a significant fraction of cells expressed Tie during megakaryocytic differentiation. These data suggest that, in humans, the Tie receptor and presumably its ligand may function at an early stage of hematopoietic cell differentiation. 相似文献
85.
Identification of a cellular polypeptide that distinguishes between acute lymphoblastic leukemia in infants and in older children 总被引:1,自引:0,他引:1
Hanash SM; Kuick R; Strahler J; Richardson B; Reaman G; Stoolman L; Hanson C; Nichols D; Tueche HJ 《Blood》1989,73(2):527-532
We analyzed the polypeptide pattern of leukemic cells of infants and older children with acute lymphoblastic leukemia (ALL), using two- dimensional polyacrylamide gel electrophoresis (PAGE). Patterns were analyzed for the occurrence of a previously detected cytosolic polypeptide, designated L3. Quantitative analysis of L3 in 12 infants and 91 older children with non-T ALL indicated lack of expression of polypeptide L3 in leukemic cells of infants which, in most cases, expressed HLA-DR and CD19 and lacked CD10. Quantitative analysis of L3 in relation to cell surface marker expression revealed that L3 was limited in its occurrence to non-T ALL and was not coordinately expressed with any of the surface markers included in the study. Among patients in the HLA-DR-positive, CD19-positive, and CD10-negative group, different levels of polypeptide L3 were observed between infants and older children. These results indicate differences in leukemic cell constituents between infants and older children with ALL and an otherwise similar cell surface marker phenotype. 相似文献
86.
Hooijkaas H; Hahlen K; Adriaansen HJ; Dekker I; van Zanen GE; van Dongen JJ 《Blood》1989,74(1):416-422
We investigated whether an indirect nuclear terminal deoxynucleotidyl transferase (TdT) immunofluorescence (IF) assay on single cells present in the cerebrospinal fluid (CSF) is more effective than conventional cytomorphology for early detection or exclusion of (minimal) meningeal leukemic infiltration in patients with a TdT+ malignancy. During a 5- year follow-up study, 1,661 consecutive CSF samples from 113 children with a TdT+ acute lymphoblastic leukemia (ALL) (n = 100), a TdT+ acute nonlymphoblastic leukemia (ANLL) (n = 8), or a TdT+ non-Hodgkin's lymphoma (NHL) (n = 5) were analyzed. In 1,511 (91.9%) of 1,643 evaluable CSF samples, the positive and negative findings of both cytomorphology and the TdT-IF assay were concordant. In 47 (2.9%) samples from 28 patients, the cytomorphology was suspect while the TdT- IF assay was negative; follow-up as long as 58 months revealed no CNS leukemia in any patient. In 85 (5.2%) samples, cytomorphology was negative (n = 70) or suspect (n = 15) but TdT+ cells were detected. RBC contamination seriously hampered evaluation in 31 of these 85 samples. From the remaining 54 TdT+ samples from 29 patients, 40 samples preceded overt CNS leukemia in 20 patients. Two consecutive findings of TdT+ cells in the CSF were always followed by overt CNS leukemia. At initial diagnosis, 11 children had TdT+ cells in their RBC-free CSF. In one of these children, morphology was suspect; a repeated lumbar puncture was positive on both assays. Thus, initial CNS leukemia was diagnosed. In the other ten children, morphology was negative. In six of them, CNS leukemia was diagnosed 2 to 20 months later. In 32 other children examined at initial diagnosis, neither TdT+ cells nor blasts were observed in the CSF. In none of these patients was a CNS leukemia diagnosed after a follow-up of 2.5 to 57 months (median 24 months). In 207 control CSF samples from 58 children with TdT- oncologic, hematologic, or infectious diseases, no TdT+ cells could be detected. The TdT-IF assay is easy to perform and is a more reliable diagnostic tool for detection of CNS leukemia at an early stage than is cytomorphology. At initial diagnosis, the finding of Tdt+ cells in a RBC-free CSF sample with a negative cytomorphology is highly predictive for development of overt CNS leukemia. 相似文献
87.
A patient with plasma cell myeloma producing only Bence Jones lambda protein was found to have pale intranuclear inclusions in the majority of the bone marrow plasma cells. These inclusions, previously undescribed in myeloma patients producing only Bence Jones protein, contained Bence Jones lambda protein, were non-electron dense, bound by a single membrane, and contained no cytoplasmic structures. Intracytoplasmic inclusions were not present, and the perinuclear cistern was not dilated. Thus, the inclusions may represent intranuclear protein synthesis with anomalous release in the abnormal cells. 相似文献
88.
Previous studies on patients with storage pool deficiency (SPD) who are specifically deficient in platelet dense granules (delta-SPD) have suggested a role for dense granule substances, in all likelihood adenosine diphosphate (ADP), in mediating thrombus formation on subendothelium at high shear rates. The role of dense granule substances in mediating platelet adhesion appears to be more complicated Previous studies in delta-SPD suggested an adhesion defect that was strongly influenced by the patient's hematocrit (Hct) value. To explore further the possibility that red blood cells (RBCs) may influence the role that platelet storage granules play in mediating adhesion at high shear rates, we have measured adhesion (and thrombus formation) throughout a preselected range of Hct values (30% to 60%) in normal subjects and in patients with delta-SPD. The present studies confirm the defect in platelet adhesion in patients with delta-SPD, most significantly at Hct values of 30% to 40%. This defect (but not that of thrombus formation) can be completely corrected by the addition of RBCs. The correction of the platelet adhesion defect by RBCs was specific for delta-SPD; it was not observed in either von Willebrand's disease or thrombasthenia. Studies performed on normal blood under conditions that could be expected to block any effect of ADP on adhesion and an analysis of the type of adhesion defect in delta-SPD suggest that ADP may be involved in the process required for platelet spreading on the subendothelium. The corrective effect of RBCs on platelet adhesion in delta-SPD appears to be chemical rather than physical in nature, possibly due to shear-induced release of RBC ADP or to other recently described properties of RBCs that enhance collagen- induced platelet interactions. 相似文献
89.
Holler E; Kolb HJ; Mittermuller J; Kaul M; Ledderose G; Duell T; Seeber B; Schleuning M; Hintermeier-Knabe R; Ertl B 《Blood》1995,86(3):890-899
Contribution of host-related cytokine release in the course of pretransplant conditioning to early tissue damage and induction of acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT) has been shown in experimental models. We performed a clinical phase I/II trial applying a monoclonal antibody neutralizing human tumor necrosis alpha (TNF alpha) during pretransplant conditioning as additional prophylaxis in high-risk patients admitted to allogeneic BMT; TNF alpha serum levels and clinical courses in 21 patients receiving anti-TNF alpha prophylaxis were compared with data from 22 historical controls. Absence of significant release of TNF alpha in the period of busulphan (BUS) treatment, but significant induction of TNF alpha by total body irradiation (TBI) and cyclophosphamide (CY) conditioning were correlated with significantly earlier onset of acute GVHD in patients receiving TBI/CY regimens as compared with BUS/CY-treated patients. Prophylactic application of monoclonal anti-TNF alpha seemed to postpone onset of acute GVHD from day 15 to day 25 (P < .05) after TBI/CY and from day 33 to day 53 after BUS/CY (P < .10) conditioning. Application of monoclonal anti-TNF alpha in low and intermediate doses was safe and not associated with an increased incidence of infectious or hematologic complications. Thus, our data provide indirect and direct evidence for involvement of conditioning-related cytokine release in induction of early acute GVHD in the clinical setting and support further investigation of this novel approach in randomized trials. 相似文献
90.
Marrow harvesting from normal donors 总被引:4,自引:2,他引:4
Buckner CD; Clift RA; Sanders JE; Stewart P; Bensinger WI; Doney KC; Sullivan KM; Witherspoon RP; Deeg HJ; Appelbaum FR 《Blood》1984,64(3):630-634
The experience at a single institution in harvesting marrow for allogeneic transplantation on 1,270 occasions from 1,160 normal donors is presented in detail, together with an analysis of all the donor complications. Four donors were less than 2 years old, and the youngest was 6 1/2 months. No special difficulties were encountered with these young donors. Hospitalization time was three days or less for 99% of the procedures. Six donors had life-threatening complications; three of a cardiopulmonary and two of an infectious nature, and one cerebrovascular embolic episode. Significant operative site morbidity, usually transient neuropathies, occurred in ten procedures. Ten percent of the donations were associated with transient postoperative fever of unknown origin. Increasing donor age was associated with a reduction of the cellularity of the marrow harvest. The use of stored autologous blood permitted the avoidance of blood bank transfusion in 81% of males, 69% of females, and 50% of children. It was concluded that the procedure was associated with a very low risk of complication, but that the involvement of normal donors in such an operation justifies stringent monitoring. 相似文献