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   1466篇
  免费   75篇
  国内免费   4篇
耳鼻咽喉   8篇
儿科学   71篇
妇产科学   35篇
基础医学   147篇
口腔科学   45篇
临床医学   132篇
内科学   329篇
皮肤病学   24篇
神经病学   38篇
特种医学   419篇
外科学   143篇
综合类   41篇
预防医学   31篇
眼科学   6篇
药学   39篇
  1篇
肿瘤学   36篇
  2023年   7篇
  2022年   6篇
  2021年   10篇
  2020年   13篇
  2019年   10篇
  2018年   10篇
  2017年   14篇
  2016年   13篇
  2015年   16篇
  2014年   32篇
  2013年   35篇
  2012年   19篇
  2011年   31篇
  2010年   38篇
  2009年   56篇
  2008年   24篇
  2007年   39篇
  2006年   37篇
  2005年   29篇
  2004年   20篇
  2003年   21篇
  2002年   12篇
  2001年   19篇
  2000年   14篇
  1999年   21篇
  1998年   80篇
  1997年   81篇
  1996年   79篇
  1995年   66篇
  1994年   41篇
  1993年   60篇
  1992年   15篇
  1991年   17篇
  1990年   25篇
  1989年   56篇
  1988年   42篇
  1987年   46篇
  1986年   54篇
  1985年   69篇
  1984年   38篇
  1983年   30篇
  1982年   28篇
  1981年   31篇
  1980年   37篇
  1979年   5篇
  1978年   18篇
  1977年   24篇
  1976年   21篇
  1975年   20篇
  1969年   5篇
排序方式: 共有1545条查询结果,搜索用时 31 毫秒
991.
Subtypes of cutaneous T-cell lymphoma defined by expression of leu-1 and Ia   总被引:5,自引:0,他引:5  
Wood  GS; Deneau  DG; Miller  RA; Levy  R; Hoppe  RT; Warnke  RA 《Blood》1982,59(5):876-882
Monoclonal antibodies were used to characterize immunohistologically the expression of cellular antigens in 25 patients with cutaneous T- cell lymphoma (CTCL). Although all cases expressed the Leu-2a-/Leu-3a+ immunophenotype characteristic of helper T cells, four subtypes were defined based on variable expression of Leu-1 and Ia. In individual patients, the immunophenotype was constant irrespective of body compartment sampled or interim therapy. Ia+ non T-cells typically constituted one-third of the cellular infiltrate. Along with neoplastic cells, Ia+/T6+ dendritic cells were observed within Pautrier microabscesses, dermis, and individually throughout the epidermis. It will be important to determine if different CTCL immunophenotypes represent different biologic subsets of disease or have prognostic relevance. Prospective studies will be facilitated by single- and double-label immunohistologic techniques that allow the simultaneous evaluation of cellular antigen expression and architectural detail.  相似文献   
992.
Izuhara  K; Feldman  RA; Greer  P; Harada  N 《Blood》1996,88(10):3910-3918
We have previously demonstrated that interleukin-4 (IL-4) induces tyrosine phosphorylation of a protein closely related or identical to the c-fes proto-oncogene product (FES) and association of this protein with the IL-4 receptor alpha chain (IL-4R alpha). IL-4 is known to induce association of phosphatidylinositol-3 (PI3) kinase with the IL- 4R alpha. Since FES contains the consensus motifs for PI3 kinase binding, we tested the possibility that FES may associate with PI3 kinase upon IL-4 stimulation. We demonstrate herein that IL-4 stimulation induced rapid association of FES or a related protein with PI3 kinase in mouse T-cell lines. We also show an association of human FES (hFES) with the src homology 2 (SH2) domain of PI3 kinase in a COS7 cell expression system. The in vitro PI3 kinase assay using COS7 cells suggested that hFES partly contributes to the association between the hIL-4R alpha and PI3 kinase. We have further identified the important region in the cytoplasmic domain of the hIL-4R alpha for association of tyrosine-phosphorylated hFES with the hIL-4R alpha and SH2 domain of PI3 kinase using a COS7 cell expression system. These results suggest that FES or a related protein/PI3 kinase pathway may play a role in the pleiotropic effects of IL-4.  相似文献   
993.
The pharmacokinetics, safety, and efficacy in marrow transplantation of FK506-based immunosuppression for graft-versus-host disease (GVHD) prophylaxis was evaluated in an open label pilot study of 18 patients. Patients more than 12 years of age (median, 35 years; range, 15 to 50 years) with advanced hematologic malignancies receiving HLA-matched sibling marrow grafts were randomized to receive FK506 alone, FK506 and methotrexate (MTX), or FK506 and methyl-prednisolone. Of 17 evaluable patients, all had evidence of sustained marrow engraftment. The median time to an absolute neutrophil count of greater than 500/microL was 15 days for patients receiving FK506 alone or FK506 plus methylprednisolone and 23 days for FK506 plus short MTX. Pharmacokinetic studies did not show any significant difference in clearance of FK506 when administered alone or in combination with methylprednisolone or MTX. The mean bioavailability after oral administration in these same three groups was 0.49 +/- 0.1, 0.27 +/- 0.12, and 0.16 +/- 0.08, respectively (P = .003). The decrease in bioavailability may have resulted from an exacerbation of radiation- induced gastroenteritis by MTX. The most significant adverse effect associated with the administration of FK506 was nephrotoxicity, which occurred in 14 of 18 patients (78%). The mean glomerular filtration rate, determined by clearance of (99MTc)DTPA, decreased to 56% (+/- 18%) of the pretransplant baseline level by week 8 (P = .002). Eight of 18 patients (44%) developed grades II-IV acute GVHD, predominantly of the skin and gastrointestinal tract. The actuarial probability of transplant-related mortality during the first 100 days was 24%. The actuarial probability of 1-year disease-free survival was 39%. In conclusion, although bioavailability of FK506 may be affected in patients receiving MTX, this study suggests that FK506 may have a role in the management of patients after allogeneic marrow transplantation.  相似文献   
994.
We report the development of a potent anti-CD38 immunotoxin capable of killing human myeloma and lymphoma cell lines. The immunotoxin is composed of an anti-CD38 antibody HB7 conjugated to a chemically modified ricin molecule wherein the binding sites of the B chain have been blocked by covalent attachment of affinity ligands (blocked ricin). Conjugation of blocked ricin to the HB7 antibody has minimal effect on the apparent affinity of the antibody and no effect on the ribosome-inactivating activity of the ricin A-chain moiety. Four to six logs of CD38+ tumor cell line kill was achieved at concentrations of HB7-blocked ricin in the range of 0.1 to 3 nmol/L. Low level of toxicity for normal bone marrow (BM) granulocyte-macrophage colony- forming units (CFU-GM), burst-forming units-erythroid (BFU-E), colony- forming units-granulocyte/erythroid/monocyte/macrophage (CFU-GEMM) cells was observed. Greater than two logs of CD38+ multiple myeloma cells were depleted from a 10-fold excess of normal BM mononuclear cells (BMMCs) after an exposure to HB7-blocked ricin under conditions (0.3 nmol/L) that were not very toxic for the normal BM precursors. HB7- blocked ricin was tested for its ability to inhibit protein synthesis in fresh patients' multiple myeloma cells and in normal BMMCs isolated from two healthy volunteers; tumor cells from four of five patients were 100-fold to 500-fold more sensitive to the inhibitory effect of HB7-blocked ricin than the normal BM cells. HB7 antibody does not activate normal resting peripheral blood lymphocytes, and HB7-blocked ricin is not cytotoxic toward these cells at concentrations of up to 1 nmol/L. The potent killing of antigen-bearing tumor cells coupled with a lack of effects on peripheral blood T cells or on hematopoietic progenitor cells suggests that HB7-blocked ricin may have clinical utility for the in vivo or in vitro purging of human multiple myeloma cells.  相似文献   
995.
Cakmak M  Cakmak N  Arikan E  Sert A  Say AE  Ersek B 《Angiology》2003,54(5):625-629
Arteriovenous fistulas are abnormal connections between the high-pressure and high-resistance arterial system and the venous system with opposite features. Due to its lower resistance, the blood preferentially flows via the fistula rather than through the capillary bed. The amount of shunt flow depends on its size and proximity to the heart. Due to the increase in circulating volume, progressive dilation develops in the whole vascular system proximal to the shunt. Cardiomegaly and venous distention may return to normal after surgical repair of this vascular abnormality. Two cases are presented of heart failure due to traumatic arteriovenous fistula, one of which was between the right renal artery and inferior vena cava and the other between the left renal artery and renal vein.  相似文献   
996.
Ohlin  AK; Marlar  RA 《Blood》1995,85(2):330-336
Thrombomodulin (TM) is the anticoagulant endothelial cell membrane- bound protein cofactor in the thrombin-mediated activation of protein C (PC). It has been clearly demonstrated that the anticoagulant and profibrinolytic functions of the PC system are important for the prevention of a thromboembolic disease. Patients with PC, protein S, or PC "'cofactor"' deficiency and/or dysfunction develop thromboembolic diseases. However, the molecular abnormality in at least 20% to 30% of thrombophilic patients cannot be identified by hitherto recognized defects. A putative pathologic lesion in the TM gene could be one of several candidates for these prothrombotic mutations. A directed search strategy for deletions, insertions, or point mutations in the TM gene has not been performed. Therefore, in the present study, we have analyzed the entire TM gene, including the promoter region, by polymerase chain reaction-single-strand conformation polymorphism (PCR- SSCP) in normal healthy volunteers and in patients presenting with a thromboembolic disease. We have identified a patient with a thromboembolic disease and a TM point mutation. In a 45-year-old Hispanic man with a documented pulmonary embolism, PCR-SSCP showed an aberrant band pattern and subsequent DNA sequence analysis showed a heterozygous substitution for G1456 to T. This substitution predicts an Asp468 to a Tyr change in the amino acid sequence that is located between the transmembrane domain and the sixth epidermal growth factor- like domain. The Asp468 to Tyr change would probably lead to significant structural changes not allowing the expression of the TM protein or to a conformational change that is not functional.  相似文献   
997.
Of 33 patients who had undergone allogeneic bone marrow transplantation during first complete remission of acute nonlymphocytic leukemia, 21 patients have now been followed in continued complete remission for 6- 64 mo (median greater than 18 mo) without maintenance chemotherapy. The median age of the surviving patients is 27 yr. Transplant-related complications occurring throughout the first year after marrow grafting were fatal in 7 patients, and leukemic recurrence led to the death of 5 patients. The actuarial long-term disease-free survival is 60% and the actuarial remission rate is 79%.  相似文献   
998.
Urinary Bence Jones protein and amyloid fibril protein isolated from the subcutaneous tissue of a patient with IgD myeloma and associated amyloidosis were subjected to physicochemical and immunochemical identification. Peptide maps and amino-terminal tetrapeptide composition obtained from the two proteins were comparable. Immunochemical cross-reactivity between the two proteins, with other lambda-type amyloid and Bence Jones proteins, and with a serum component was demonstrated. The results suggest that the source of the amyloid fibril protein is an intact circulating light polypeptide chain as well as smaller amino-terminal fragments.  相似文献   
999.
Graft failure was analyzed in 625 patients receiving allogeneic bone marrow transplants from HLA-identical sibling donors as treatment for severe aplastic anemia. Sixty-eight (11%) had no or only transient engraftment. Second bone marrow transplants were successful in achieving extended survival in 16 of 27 patients with transient initial engraftment but in none of ten patients with no sign of engraftment after the first transplant. The major factors associated with a reduced risk of graft failure were use of radiation for pretransplant immunosuppression and use of cyclosporine rather than methotrexate or T- cell depletion of the donor bone marrow for prophylaxis against graft-v- host disease (GVHD). Among 266 patients prepared for transplantation with cyclophosphamide alone, the risk of graft failure was increased in patients who received previous transfusions and reduced in those who received corticosteroids for previous therapy. Neither cell dose nor administration of donor buffy coat cells affected the probability of engraftment. Although use of radiation in conditioning reduced graft failure, survival was not improved. Posttransplant treatment with cyclosporine and avoidance of pretransplant blood transfusions were associated with improved survival.  相似文献   
1000.
Combination chemotherapy is frequently used in the therapy of advanced non-small-cell lung cancer (NSCLC), but late complications are rarely recognized because of the short survival of most patients. Of 119 patients with advanced NSCLC treated with cisplatin and other drugs, four patients developed acute nonlymphocytic leukemia (ANLL). All four patients received etoposide and cisplatin with or without vindesine. Leukemia was diagnosed at 13, 19, 28, and 35 months after start of treatment. Three patients had morphologic and/or cytogenetic features of acute leukemia with significant monoblastic involvement; the fourth patient had trilineage dysplasia and cytogenetic abnormalities more commonly associated with therapy-related leukemia. Detailed analysis of the subgroup who survived longer than 1 year (24 patients) suggests that high cumulative doses of etoposide are leukemogenic; the median etoposide dose was 6,795 mg/m2 (first year only) in the four leukemic patients compared with 3,025 mg/m2 in the 20 nonleukemic patients (P less than .01). The rate of ANLL was 0.30 per person-year after the first year (95% confidence limits 0.11 to 0.90), with a cumulative risk of 15% +/- 11% at 2 years, and 44% +/- 24% at 2.5 years. We conclude that high doses of etoposide are potentially leukemogenic, and can induce a syndrome with features of acute monoblastic leukemia de novo that is distinct from other secondary leukemias.  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