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   1687篇
  免费   118篇
  国内免费   75篇
耳鼻咽喉   11篇
儿科学   70篇
妇产科学   23篇
基础医学   150篇
口腔科学   41篇
临床医学   205篇
内科学   531篇
皮肤病学   44篇
神经病学   57篇
特种医学   264篇
外科学   118篇
综合类   32篇
一般理论   1篇
预防医学   70篇
眼科学   31篇
药学   59篇
中国医学   3篇
肿瘤学   170篇
  2023年   9篇
  2022年   6篇
  2021年   19篇
  2020年   16篇
  2019年   31篇
  2018年   37篇
  2017年   23篇
  2016年   29篇
  2015年   21篇
  2014年   41篇
  2013年   27篇
  2012年   51篇
  2011年   51篇
  2010年   52篇
  2009年   63篇
  2008年   53篇
  2007年   86篇
  2006年   49篇
  2005年   57篇
  2004年   48篇
  2003年   45篇
  2002年   49篇
  2001年   45篇
  2000年   49篇
  1999年   41篇
  1998年   91篇
  1997年   76篇
  1996年   69篇
  1995年   63篇
  1994年   51篇
  1993年   46篇
  1992年   36篇
  1991年   25篇
  1990年   34篇
  1989年   39篇
  1988年   45篇
  1987年   40篇
  1986年   43篇
  1985年   33篇
  1984年   27篇
  1983年   15篇
  1982年   18篇
  1981年   11篇
  1980年   13篇
  1979年   7篇
  1978年   7篇
  1977年   18篇
  1976年   13篇
  1975年   13篇
  1968年   5篇
排序方式: 共有1880条查询结果,搜索用时 31 毫秒
71.
A 61-year-old man presented with jaundice, and subsequently underwent an extended left hepatectomy and pancreaticoduodenectomy for a cholangiocarcinoma invading the head of the pancreas. The patient developed sepsis due to a biliary leak at the hepaticojejunostomy. We describe the original use of a biodegradable stent, deployed via percutaneous transhepatic cholangiography into the Roux limb, resulting in good drainage and resolution of sepsis. The chief benefit of this procedure is the lack of need for subsequent removal as well as purported reduced biofilm accumulation. We believe this to be the first reported case of this type and the literature surrounding the subject is also discussed.  相似文献   
72.
We report a case of a female patient with chronic myelogenous leukemia who presented, 8 yr after initial diagnosis, with pancytopenia, encephalopathy, and myalgia. The tentative diagnosis was accelerated phase of chronic myelogenous leukemia. However, because the patient had been treated with cimetidine for 7 months we first omitted this drug. When cimetidine was stopped, bone marrow recovered, and myalgia and encephalopathy subsided. Immunological studies showed stimulation of the patient's lymphocyte blastogenesis by cimetidine and a marked increase in the proportion of cytotoxic/suppressor T lymphocytes after incubation of peripheral blood lymphocytes with cimetidine for 6 days. These findings indicate a role for cell-mediated immunity in the pathogenesis of cimetidine-induced pancytopenia in this patient.  相似文献   
73.
Microtubule reassembly in surface-activated platelets   总被引:2,自引:0,他引:2  
White  JG; Krumwiede  M; Sauk  JJ 《Blood》1985,65(6):1494-1503
It is generally accepted that a circumferential microtubule supports the discoid shape of resting platelets. The fate of the many-coiled polymer following platelet activation, however, has been a subject of considerable debate. Morphological investigations have suggested that the circumferential coils are constricted into tight rings around centrally concentrated organelles during platelet shape change. Biochemical studies employing colchicine-binding assays, on the other hand, have indicated that the bundle of microtubules dissolves almost completely within seconds after activation and reassembles in a new location one to four minutes later. The present study has accepted the latter hypothesis in order to examine the second part of the disassembly-reassembly theory proposed in biochemical studies. Platelets exposed to low temperatures sufficient to remove all microtubules were placed on glass slides and microscope grids to cause surface activation during rewarming. The combined stimuli of rewarming and surface activation might have been expected to cause more rapid assembly than warming alone or activation alone. This was not the case. Reassembly of microtubules during rewarming and simultaneous surface activation was not accelerated. In contrast to the constriction of microtubule rings observed during activation in control platelets, the diameters of coils that developed in chilled platelets one to two hours after rewarming and surface activation were twice those of control cells.  相似文献   
74.
Nagler RM 《Biogerontology》2004,5(4):223-233
Xerostomia is a major complaint of many elderly individuals, and although they seek medical help, it usually provides no adequate relief. This complaint is considered a major clinical problem, since not less than 25% to 50%-60% of the population over the age of 65 complain of xerostomia. By definition, Xerostomia is a subjective feeling and in up to one-third of the cases does not reflect a real reduction in salivary flow rate but rather the subjective feeling of a dry mouth. Moreover, only a minute portion of the patients suffer from xerostomia with a known aetiology such as radiotherapy or Sjögren's syndrome, while in the majority of the cases, the aetiology is assumed to be related to age, disease, various medications and drugs or is simply idiopathic. The current review focuses on age-related histological, sialometrical and sialochemical changes and on the possible mechanisms which underlie these changes. Finally, directions for further exploring the subject are suggested.  相似文献   
75.
Myelodysplastic syndromes (MDS) are characterized by chronic refractory cytopenias resulting in increased risk of infection, bleeding, and conversion to acute leukemia. In an effort to improve these cytopenias we have treated 18 patients over a 6- to 8-week period with increasing daily subcutaneous doses of recombinant human granulocyte colony-stimulating factor (G-CSF). Sixteen patients responded with improvement in neutrophil counts. On cessation of treatment these counts returned to baseline values over a 2- to 4-week period. To maintain these improved blood counts 11 patients were treated with G-CSF for more prolonged periods. Ten patients again responded with an increase in total leukocyte counts (1.6- to 6.4-fold) and absolute neutrophil counts (ANC) (3.6- to 16.3-fold), with responses persisting for 3 to 16 months. A significantly decreased risk of developing bacterial infections was noted during periods with ANC greater than 1,500/mm3 as compared with periods of time with ANC less than 1,500/mm3. Two anemic patients had a greater than 20% rise in hematocrit over the study period, and 2 additional patients had a decrease in red blood cell transfusion requirements during G-CSF treatment. Bone marrow myeloid maturation improved in 7 of 9 maintenance phase patients. Three patients progressed to acute myeloid leukemia during treatment. The drug was generally well-tolerated and no severe toxicities were noted. These data demonstrated that G-CSF administered to MDS patients by daily subcutaneous administration was well-tolerated and effective in causing persistent improvement of the neutrophil levels and marrow myeloid maturation. These effects were associated with a decreased risk of infection and, in some patients, with decreased red blood cell transfusion requirements.  相似文献   
76.
The immunophenotypes of lymphoblasts from children with newly diagnosed T-cell acute lymphoid leukemia (T-ALL, n = 101) or T-cell non-Hodgkin lymphoma (T-NHL, n = 31) were analyzed to correlate stage of thymocyte differentiation with clinical features and outcome. The 67 boys and 34 girls with T-ALL were 1 month to 18 years old (median, 8 years) with leukocyte counts ranging from 2 to 810 x 10(9)/L (median, 55 x 10(9)/L). Eighteen of these patients were black, and 70 had a mediastinal mass. Twenty-six boys and five girls with a median age of 9 years (range, 1 to 20 years) had T-NHL. Seven of these patients were black, and 24 had a mediastinal mass. The distributions of thymocyte developmental stages (early [CD7+], intermediate [CD1+ and/or CD4+ and/or CD8+], and mature [CD3+]) in cases of T-ALL and T-NHL were significantly different: 34%, 43%, and 23% v 6%, 62%, and 32% (P = .02). A comparison of the patients' clinical features according to the maturational stage of thymocytes failed to disclose significant differences in the majority of characteristics studied. However, patients with mature-stage T-NHL, with or without the addition of subjects with mature-stage T-ALL, were less likely to have a mediastinal mass (P = .02 for both comparisons). Those with intermediate-stage T-cell malignancy (T-ALL and T-NHL combined) were the subgroup most likely to have a mediastinal mass (P = .01). Response to remission induction therapy was significantly worse in the T-ALL subgroup with an early-stage phenotype: a failure rate of 21% v 0% and 6% for the two more differentiated phenotypic subgroups (P = .007). Event-free survival was not affected by thymocyte maturational stage in cases of either T-ALL or T-NHL. Despite evidence of clinical heterogeneity among the maturational stages of T-cell malignancies in children, these developmental subdivisions do not appear to be critical determinants of outcome once remission is achieved. We conclude that such phenotypes need not be included in the stratification plans for clinical trials using common induction treatment.  相似文献   
77.
We investigated the feasibility of unrelated stem cell transplantation in 21 patients with advanced stage II/III multiple myeloma after a reduced-intensity conditioning regimen consisting of fludarabine (150 mg/m(2)), melphalan (100-140 mg/m(2)), and antithymocyte globulin (ATG; 10 mg/kg on 3 days). The median patient age was 50 years (range, 32-61 years). All patients had received at least one prior autologous transplantation, in 9 cases as part of an autologous-allogeneic tandem protocol. No graft failure was observed. At day 40 complete donor chimerism was detected in all patients. Grade II to IV acute graft-versus-host disease (GVHD) was seen in 8 patients (38%), and severe grade III/IV GVHD was observed in 4 patients (19%). Six patients (37%) developed chronic GVHD, but only 2 patients (12%) experienced extensive chronic GVHD. The estimated probability of nonrelapse mortality at day 100 was 10% and at 1 year was 26%. After allografting, 40% of the patients achieved a complete remission, and 50% achieved a partial remission, resulting in an overall response rate of 90%. After a median follow-up of 13 months, the 2-year estimated overall and progression-free survival rates are 74% (95% CI, 54%-94%) and 53% (95% CI, 29%-87%), respectively. A shorter progression-free survival was seen in patients who already experienced relapse to prior autograft (26% versus 86%, P =.04). Dose-reduced conditioning with pretransplantation ATG followed by unrelated stem cell transplantation provides durable engraftment and donor chimerism, reduces substantially the risk of transplant-related organ toxicity, and induces high remission rates.  相似文献   
78.
Chronic graft versus host disease (cGVHD) is a major complication that can develop after bone marrow transplantation. It involves an immune-mediated attack by transplanted donor lymphocytes, and often results in inflammatory damage of host target organs. Immune hyporesponsiveness induced by oral antigen administration has been recently shown to prevent the development of cGVHD in a murine model. The aim of this study was to evaluate whether tolerance induction in bone marrow transplant (BMT) recipients after transplantation, toward their pretransplant antigens, can alleviate preexisting cGVHD in a mouse model. cGVHD was generated by infusing 2.5 x 10(7) splenocytes from B10.D2 donor mice, to sublethally irradiated (6 Gy) BALB/c recipient mice, which differ by minor histocompatibility antigens. Transplantation resulted in cGVHD, with characteristic scleroderma-like cutaneous fibrosis, increased skin collagen content, decreased body weight, and hepatic and small bowel inflammation. Oral tolerance was induced by feeding recipient BALB/c mice with proteins extracted from BALB/c splenocytes for 11 days after B10.D2 splenocyte transplantation. Tolerance induction was evidenced by a significant reduction in mixed lymphocyte response of effector splenocytes from tolerant BALB/c mice transplanted with B10.D2 splenocytes against BALB/c target splenocytes. Oral tolerance decreased skin collagen deposits. Reduction of collagen alpha1(I) gene expression and skin collagen were shown by in situ hybridization and histochemistry, respectively. Liver and bowel biopsy specimens revealed less inflammation. Serum IL-10 levels were higher in tolerant mice than in controls, whereas IFNgamma was significantly reduced. Oral tolerance of BMT recipients toward their pretransplant antigens after splenocyte transplantation down-regulated the immune attack by transplanted cells, thus ameliorating cGVHD.  相似文献   
79.
We have reported encouraging results of unrelated cord blood transplantation for patients with lymphoid malignancies. Whether those outcomes are comparable to matched unrelated donor transplants remains to be defined. We studied 645 adult patients with mature lymphoid malignancies who received an allogeneic unrelated donor transplant using umbilical cord blood (n=104) or mobilized peripheral blood stem cells (n=541) after a reduced-intensity conditioning regimen. Unrelated cord blood recipients had more refractory disease. Median follow-up time was 30 months. Neutrophil engraftment (81% vs. 97%, respectively; P<0.0001) and chronic graft-versus-host disease (26% vs. 52%; P=0.0005) were less frequent after unrelated cord blood than after matched unrelated donor, whereas no differences were observed in grade II–IV acute graft-versus-host disease (29% vs. 32%), non-relapse mortality (29% vs. 28%), and relapse or progression (28% vs. 35%) at 36 months. There were also no significant differences in 2-year progression-free survival (43% vs. 58%, respectively) and overall survival (36% vs. 51%) at 36 months. In a multivariate analysis, no differences were observed in the outcomes between the two stem cell sources except for a higher risk of neutrophil engraftment (hazard ratio=2.12; P<0.0001) and chronic graft-versus-host disease (hazard ratio 2.10; P=0.0002) after matched unrelated donor transplant. In conclusion, there was no difference in final outcomes after transplantation between umbilical cord blood and matched unrelated donor transplant. Umbilical cord blood is a valuable alternative for patients with lymphoid malignancies lacking an HLA-matched donor, being associated with lower risk of chronic graft-versus-host disease.  相似文献   
80.
Safety profiles of oral PI3K inhibitors have resulted in US FDA black box warnings regarding fatal/serious toxicities. The approved intravenous PI3K inhibitor copanlisib has low incidence of severe toxicities and no black box warnings, but chronic treatment effects were unknown. We provide an update on safety and efficacy of copanlisib with a minimum 2-year follow-up of the CHRONOS-1 study. A total of 142 patients with histologically confirmed indolent B-cell lymphoma who had relapsed after or were refractory to ≥2 prior treatments received intravenous copanlisib 60 mg on days 1, 8, and 15 (28-day cycle). The primary efficacy endpoint was objective response rate (ORR) after ≥4 cycles (independent assessment). The predominant histology was follicular lymphoma (n = 104). The ORR was 60.6% (seven additional complete responses since primary analysis). Secondary endpoints of median duration of response, progression-free survival, and overall survival were 14.1 months (median follow-up, 16.1 months), 12.5 months (median follow-up, 14.0 months), and 42.6 months (median follow-up, 31.5 months), respectively. Median safety follow-up was 6.7 months; 26% of patients received treatment for >1 year. Common treatment-emergent adverse events (TEAEs) (all grade/grade 3/grade 4) were transient hyperglycemia (50.0%/33.1%/7.0%), diarrhea (35.2%/8.5%/0%), transient hypertension (29.6%/23.9%/0%), and neutropenia (28.9%/9.2%/14.8%). Serious AEs were largely unchanged, with no new cases of pneumonitis (4.2%), diarrhea (2.8%), or grade 5 events. Note, TEAEs showed no evidence for increased incidence or worsening following longer exposure in patients treated >1 year. Long-term follow-up of patients with relapsed/refractory indolent B-cell lymphoma treated with intravenous copanlisib demonstrated durable, enhanced responses without evidence of worsening TEAEs, as reported for orally administered PI3K inhibitors.  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