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   309篇
  免费   19篇
  国内免费   16篇
耳鼻咽喉   6篇
儿科学   17篇
妇产科学   3篇
基础医学   20篇
口腔科学   4篇
临床医学   45篇
内科学   79篇
皮肤病学   10篇
神经病学   5篇
特种医学   69篇
外科学   14篇
综合类   8篇
预防医学   11篇
眼科学   2篇
药学   31篇
肿瘤学   20篇
  2020年   3篇
  2018年   3篇
  2017年   2篇
  2016年   3篇
  2015年   7篇
  2014年   7篇
  2013年   8篇
  2012年   4篇
  2011年   12篇
  2010年   7篇
  2009年   8篇
  2008年   6篇
  2007年   21篇
  2006年   3篇
  2005年   6篇
  2004年   3篇
  2003年   3篇
  2002年   5篇
  2001年   5篇
  2000年   5篇
  1999年   5篇
  1998年   14篇
  1997年   20篇
  1996年   22篇
  1995年   18篇
  1994年   14篇
  1993年   10篇
  1992年   4篇
  1991年   2篇
  1990年   13篇
  1989年   19篇
  1988年   13篇
  1987年   11篇
  1986年   3篇
  1985年   4篇
  1984年   1篇
  1983年   3篇
  1982年   7篇
  1981年   5篇
  1979年   3篇
  1978年   3篇
  1977年   4篇
  1976年   3篇
  1975年   5篇
  1959年   1篇
  1958年   2篇
  1957年   1篇
  1954年   4篇
  1949年   3篇
  1948年   3篇
排序方式: 共有344条查询结果,搜索用时 953 毫秒
71.
The purpose of this position statement is to suggest ways in which future appropriate use criteria (AUC) for coronary revascularization might be restructured to: (1) incorporate improvement in quality of life and angina relief as primary goals of therapy, (2) integrate the findings of recent trials into quality appraisal, (3) employ the combined information of the coronary angiogram and invasive physiologic measurements together with the results of stress test imaging to assess risk, and (4) recognize the essential role that patient preference plays in making individualized therapeutic decisions. The AUC is a valuable tool within the quality assurance process; it is vital that interventionists ensure that percutaneous coronary intervention case selection is both evidence-based and patient oriented. Appropriate patient selection is an important quality indicator and adherence to evidence-based practice should be one metric in a portfolio of process and outcome indicators that measure quality.  相似文献   
72.
We administered a combination of rubidazone, cytosine arabinoside, vincristine, and prednisone (ROAP) to 91 patients with acute myelogenous leukemia who were 50 yr of age or older. These patients had been identified in previous studies to be a group with a relatively poor prognosis. One-third of the patients had an antecedent hematologic disorder prior to treatment. Forty patients (48%) obtained a complete hematologic and clinical remission. A history of an antecedent hematologic disorder, male sex, and absence of Auer rods were adverse factors for achieving remission in this older population. More than half of the patients achieved remission in one course. The major cause of failure to obtain a remission was death due to infection, 40% of which were caused by fungi. Resistance to chemotherapy, although uncommon, was noted more frequently in patients with an antecedent hematologic disorder. Univariate and multivariate prognostic factor analysis was used to compare these patients with a historical control group treated with a program in which adriamycin was used instead of rubidazone (AdOAP). No significant difference in remission rate was detected. Cyclocytidine was used as a maintenance agent in this study, and while the median remission duration was only 37 wk, 30% of patients are expected to be in remission for 2 yr. Chemotherapy programs combining an anthracycline with cytosine arabinoside, given to older patients in similar fasion to younger patients will achieve remissions in one-half of a group of older patients. These remissions are of comparable quality to those of younger patients. Mathematical models derived from analysis of prognostic factors are of use in identifying patients likely to fail these programs who are in need of innovative approaches to treatment.  相似文献   
73.
Intracellular hemoglobin S (HbS) polymerization is most likely to be the primary determinant of the clinical and biologic manifestations of sickle cell disease (SCD). Fetal hemoglobin (HbF) does not enter the HbS polymer and its intracellular expression in sickle erythrocytes inhibits polymerization. HbF levels, high at birth but decreasing thereafter, protect the newborn from the clinical manifestations of this hemoglobinopathy. We have measured the sequential changes in HbF, F reticulocytes, and F cells in the first 2 years of life in 25 children with SCD and compared the results with those obtained in 30 normal children (AA). We have also calculated HbF per F cell (F/F cell), the preferential survival of F cells versus non-F cells, as measured by the ratio F cells versus F reticulocytes (FC/FR) and polymer tendency at 40% and 70% oxygen saturation. HbF levels decreased from about 80.4% +/- 4.0% at birth to 9.2% +/- 2.9% at 24 months. During this time, we observed a regular decrease of the F reticulocytes and the F cells. The kinetics of the decline of F/F cell was comparable with the decline of HbF, rapid from birth (mean, 27.0 +/- 3.6 pg) to 12 months of age (mean, 8.5 +/- 1.5 pg) and then slower from 12 to 24 months of age (mean, 6.2 +/- 1.0 pg) in the SCD children. In the AA children, the decrease in HbF, due to changes in both numbers of F cells and F/F cell, was more precipitous, reaching steady-state levels by 10 months of age. Calculated values for mean polymer tendency in the F-cell population showed that polymerization should begin to occur at 40% oxygen saturation at about 3 months and increase progressively with age, whereas polymerization at 70% oxygen saturation would not occur until about 24 months. These values correspond to HbF levels of 50.8% +/- 10.8% and 9.2% +/- 2.9%, respectively, and F/F cell levels of 15.6 +/- 4.5 pg and 6.2 +/- 1.0 pg, respectively. In the non--F-cell population, polymerization was expected at birth at both oxygen saturation values. Three individuals had significantly greater predicted polymerization tendency than the remainder of the group because of early decreases in HbF. These individuals in particular, the remainder of the cohort, as well as other recruited newborns, will be studied prospectively to ascertain the relationship among hematologic parameters, which determine polymerization tendency and the various clinical manifestations of SCD.  相似文献   
74.
Schick  PK; Tuszynski  GP; Vander Voort  PW 《Blood》1983,61(1):163-166
The lipid composition of platelet cytoskeletons was analyzed. Triton X- 100 (0.5%) was used to prepare cytoskeletons from thrombin-treated platelets. The lipid/protein ratio of platelet cytoskeletons was 0.260 and the phospholipid/protein ratio was 0.177, which were comparable to the ratios present in platelets. However, there was a selective enrichment of platelet lipids in platelet cytoskeletons. Only 2 of the 5 major platelet phospholipids were detected. About 14% platelet sphingomyelin and 2% platelet phosphatidylcholine were present in platelet cytoskeletons. Only 1 of the 4 platelet neutral glycolipids, trihexosyl ceramide, was detected and was about 7% of that in intact platelets. Two percent of platelet hematoside, the predominant ganglioside in platelets, was found in cytoskeletons. Six percent of platelet cholesterol was present in platelet cytoskeletons, while no other neutral lipid could be detected. The study demonstrates that the lipid/protein ratio of platelet cytoskeletons is similar to that in platelets, but the composition of cytoskeleton lipids is specific and distinctly different from that in platelets. The selective glycolipid and phospholipid composition of cytoskeletons may be important for cytoskeleton and platelet function.  相似文献   
75.
AMSA was evaluated in the treatment of 109 adults with previously treated acute leukemia. Of the 102 evaluable patients, 82 had AML, 17 ALL, and 3 CML in blastic phase. A number of different dose schedules of AMSA were explored, and we conclude that the optimum dose of AMSA for remission induction in acute leukemia is 120 mg/sq m/day for 5 days. Complete remissions were observed in 23 (28%) patients with AML and in 1 patient with ALL. Patients who achieved complete remission were maintained on AMSA using a dose of 30-40 mg/sq m/day for 5 days repeated at 4-wk intervals. The median duration of complete remission was 12 wk (3-59 wk), and the responders survived significantly longer than the failures (27 wk versus 8 wk, p = 0.002). The side effects associated with AMSA therapy included mild nausea and vomiting, stomatitis, diarrhea, phlebitis, alopecia, and myelosuppression-related infections. Our results indicate that AMSA is a useful new antileukemic agent for the treatment of relapsed acute leukemia and appears to have activity comparable to that of the currently available drugs, such as cytarabine and the anthracycline antibiotics.  相似文献   
76.
Results of second-line chemotherapy regimens against lymphoma have usually been poor. In this study, we used a combination of ifosfamide, methotrexate, and VP-16 to treat 52 patients with lymphoma who had either relapsed or who had failed to attain a complete remission on front-line treatment. Thirty-two patients (62%) responded (CR 37%, PR 25%) and 10 (19%) had a minor response. The median relapse-free interval of the responding patients was 12 mo, and the median survival of the whole group was 15 mo. Of the 18 patients who achieved complete remission, 10 still remain free of any evidence of disease. The factor that best predicted for response to IMVP-16 was the quality of the remission achieved on front-line therapy. In view of the poor prognosis associated with recurrent lymphoma, the results obtained with this study are considered most encouraging. Patients with recurrent lymphoma can be successfully salvaged by the use of this combination regimen, especially if introduced early after relapse or preferably before progressive disease develops.  相似文献   
77.
Schwartz  JH; Cannellos  GP 《Blood》1975,46(1):11-16
The effect of hydroxyurea in 35 patients with chronic granulocytic leukemia (CGL), who either had entered an accelerated phase of the disease or had experienced excessive myelosuppression following alkylating agents, was studied. By either intravenous or oral administration, the drug was successful in reducing peripheral leukocyte and blast counts in all cases and in reducing splenomegaly in 13 of 17 patients. The median duration of disease control was 75 days in myeloproliferative acceleration and 27 days in frank blastic transformation. Mild nausea and vomiting were experienced by most patients, but reversible bone marrow suppression occured in only three patients. The drug proved useful in 19 patients who demonstrated myeloproliferative acceleration, especially in controlling excessive leukocytosis and/or thrombocytosis. Rapid reduction of an elevated blast cell count was achieved in nine patients who presented in blastic crisis, in an attempt to eliminate the associated risk of cerebral vascular leukostasis. Five patients who required treatment for their disease following splenectomy in the chronic phase were also well controlled. Hydroxyurea appears to have a definite role in the management of these hematologic complications of CGL.  相似文献   
78.
79.
BACKGROUND: Previous studies have not resolved the importance of several potential risk factors for the development of childhood atopy, airway hyperresponsiveness, and wheezing, which would allow the rational selection of interventions to reduce morbidity from asthma. Risk factors for these disorders were examined in a birth cohort of 1037 New Zealand children. METHODS: Responses to questions on respiratory symptoms and measurements of lung function and airway responsiveness were obtained every two to three years throughout childhood and adolescence, with over 85% cohort retention at age 18 years. Atopy was determined by skin prick tests at age 13 years. Relations between parental and neonatal factors, the development of atopy, and features of asthma were determined by comparison of proportions and logistic regression. RESULTS: Male sex was a significant independent predictor for atopy, airway hyper-responsiveness, hay fever, and asthma. A positive family history, especially maternal, of asthma strongly predicted childhood atopy, airway hyperresponsiveness, asthma, and hay fever. Maternal smoking in the last trimester was correlated with the onset of childhood asthma by the age of 1 year. Birth in the winter season increased the risk of sensitisation to cats. Among those with a parental history of asthma or hay fever, birth in autumn and winter also increased the risk of sensitisation to house dust mites. The number of siblings, position in the family, socioeconomic status, and birth weight were not consistently predictive of any characteristic of asthma. CONCLUSIONS: Male sex, parental atopy, and maternal smoking during pregnancy are risk factors for asthma in young children. Children born in winter exhibit a greater prevalence of sensitisation to cats and house dust mites. These data suggest possible areas for intervention in children at risk because of parental atopy.  相似文献   
80.
OBJECTIVE: To assess whether physical growth is affected in early treated Dutch patients with phenylketonuria (PKU). METHODS: The birth weights of all 137 early detected patients with PKU born in the period from 1974 to 1988 in the Netherlands were compared with reference values. Height, head circumference, and weight were measured at the age at which treatment started (commonly about 2-3 weeks), at 6 months of age, and yearly from the child's first birthday up to the age of 10 years. These measurements were compared with reference values. RESULTS: The adjusted birth weight in patients with PKU was 141 g (95% confidence interval (CI) 66 to 216 g) less than Dutch reference values by Kloosterman and 103 g (95% CI 9 to 196 g) less compared with the birth weight of another reference group. At the age at which treatment started, z scores of patients for height by age were -0.23 (95% CI -0.44 to -0.02) and z scores for head circumference by the age were -0.25 (95% CI -0.44 to -0.06). From the age at which treatment started up to the age of 3 years z scores for height by age further decreased to -0.74 (95% confidence interval -0.93 to -0.56), after which no additional decrease occurred. In contrast, z scores for head circumference increased from -0.25 at the first visit to 0.08 (95% CI -0.14 to 0.30) at the age of 1 year, after which they remained close to zero. Weight by height was close to the expected centiles for all ages. CONCLUSION: Patients with PKU are growth retarded at birth and have smaller head circumferences than the normal population. In Dutch patients further growth retardation occurs in the first three years of life.  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