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   351篇
  免费   13篇
耳鼻咽喉   2篇
儿科学   13篇
妇产科学   3篇
基础医学   34篇
口腔科学   2篇
临床医学   49篇
内科学   137篇
皮肤病学   9篇
神经病学   16篇
特种医学   5篇
外科学   61篇
预防医学   11篇
眼科学   2篇
药学   6篇
肿瘤学   14篇
  2023年   2篇
  2022年   3篇
  2021年   4篇
  2020年   4篇
  2019年   4篇
  2018年   7篇
  2016年   4篇
  2015年   13篇
  2014年   13篇
  2013年   14篇
  2012年   24篇
  2011年   13篇
  2010年   13篇
  2009年   11篇
  2008年   27篇
  2007年   16篇
  2006年   24篇
  2005年   23篇
  2004年   8篇
  2003年   9篇
  2002年   9篇
  2001年   6篇
  2000年   11篇
  1999年   7篇
  1998年   6篇
  1996年   3篇
  1995年   2篇
  1994年   3篇
  1992年   5篇
  1991年   9篇
  1990年   8篇
  1989年   5篇
  1988年   6篇
  1987年   4篇
  1986年   5篇
  1985年   5篇
  1984年   4篇
  1983年   4篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1978年   4篇
  1977年   3篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1973年   4篇
  1972年   1篇
  1942年   1篇
  1899年   1篇
排序方式: 共有364条查询结果,搜索用时 15 毫秒
1.
The degree of matching of HLA genes between the selected donor and recipient is an important aspect of the selection of unrelated donors for allogeneic bone marrow transplantation (UBMT). The most sensitive methods currently used are serological typing of HLA class I genes, mixed lymphocyte culture (MLC), IEF and molecular genotyping of HLA class II genes by direct sequencing of PCR products. Serological typing of class I antigenes (A, B and C) fails to detect minor differences demonstrated by direct sequencing of DNA polymorphic regions. Molecular genotyping of HLA class I genes by DNA analysis is costly and work-intensive. To improve compatibility between donor and recipient, we have set up a new rapid and non-radioisotopic application of the ‘fingerprinting PCR’ technique for the analysis of the polymorphic second exon of the HLA class I A, B and C genes. This technique is based on the formation of specific patterns (PCR fingerprints) of homoduplexes and heterodu-plexes between heterologous amplified DNA sequences. After an electrophoretic run on non-denaturing polyacrylamide gel, different HLA class I types give allele-specific banding patterns. HLA class I matching is performed, after the gel has been soaked in ethidium bromide or silver-stained, by visual comparison of patients’ fingerprints with those of donors. Identity can be confirmed by mixing donor and recipient DNAs in an amplification cross-match. To assess the technique, 10 normal samples, 22 related allogeneic bone marrow transplanted pairs and 10 unrelated HLA-A and HLA-B serologically matched patient-donor pairs were analysed for HLA class I polymorphic regions. In all the related pairs and in 1/10 unrelated pairs, matched donor-recipient patterns were identified. This new application of PCR fingerprinting may confirm the HLA class I serological selection of unrelated marrow donors.  相似文献   
2.
The effect of early splenectomy and of polychemotherapy with hydroxyurea, busulfan, and alternate bimonthly courses of arabinosyl cytosine and vincristine plus prednisone, was evaluated in 139 previously untreated patients with chronic myeloid leukemia (CML), consecutively admitted to 18 hospitals from March 1973 to October 1974. Fifty-six patients were splenectomized and 83 patients were not splenectomized. Splenectomy did not influence the duration of chronic and blastic phase, and did not prolong survival. The prognosis of high risk patients was not improved. During the chronic phase, high platelet counts were more frequent in splenectomy group, and five patients developed thrombotic or thromboembolic complications, 5 to 19 months after the operation. The median survival of the whole group was 50 months, with 32 of 139 patients (actuarial proportion 30%) remaining alive 72 months after diagnosis, but the slope of the survival curve was similar to that of historical controls. The results of this trial suggests that new strategies should be developed for the therapy of CML.  相似文献   
3.
4.
In this paper, we review the principal theoretical models through which the dielectric function of metals can be described. Starting from the Drude assumptions for intraband transitions, we show how this model can be improved by including interband absorption and temperature effect in the damping coefficients. Electronic scattering processes are described and included in the dielectric function, showing their role in determining plasmon lifetime at resonance. Relationships among permittivity, electric conductivity and refractive index are examined. Finally, a temperature dependent permittivity model is presented and is employed to predict temperature and non-linear field intensity dependence on commonly used plasmonic geometries, such as nanospheres.  相似文献   
5.
This randomized phase III clinical trial explored the efficacy of DaunoXome (DNX) versus Daunorubicin (DNR) in acute myeloid leukaemia (AML) patients aged >60 years. Three hundred and one AML patients were randomized to receive DNR (45 mg/m(2) days 1-3) or DNX (80 mg/m(2) days 1-3) plus cytarabine (AraC; 100 mg/m(2) days 1-7). Patients in complete remission (CR) received a course of the same drugs as consolidation and then were randomized for maintenance with AraC+ all trans retinoic acid or no further treatment. Among 153 patients in the DNR arm, 78 (51.0%) achieved CR, 55 (35.9%) were resistant and 20 (13.1%) died during induction. Among 148 patients in the DNX arm, 73 (49.3%) achieved CR, 47 (31.8%) were resistant and 28 (18.9%) died during induction. Univariate analysis showed no difference as to induction results. After CR, DNX showed a higher incidence of early deaths (12.5% vs. 2.6% at 6 months, P = 0.053) but a lower incidence of relapse beyond 6 months (59% vs. 78% at 24 months, P = 0.064), with a cross in overall survival (OS) and disease-free survival (DFS) curves and a later advantage for DNX arm after 12 months from diagnosis. DNX seems to improve OS and DFS in the long-term follow-up, because of a reduction in late relapses.  相似文献   
6.
Fludarabine plus cytarabine (Ara-C) and idarubicin (FLAI) is an effective and well-tolerated induction regimen for the treatment of acute myeloid leukaemia (AML). This phase III trial compared the efficacy and toxicity of FLAI versus idarubicin plus Ara-C and etoposide (ICE) in 112 newly diagnosed AML patients <60 years. Fifty-seven patients received FLAI, as the first induction-remission course, and 55 patients received ICE. Post-induction treatment consisted of high-dose Ara-C (HDAC). After HDAC, patients in complete remission (CR) received a second consolidation course (mitoxantrone, etoposide, Ara-C) and autologous stem cell transplantation (auto-SCT) or allogeneic (allo)-SCT, according to the age, disease risk and donor availability. After a single induction course, CR rate was 74% in the FLAI arm and 51% in the ICE arm (P = 0.01), while death during induction was 2% and 9% respectively. Both haematological (P = 0.002) and non-haematological (P = 0.0001) toxicities, especially gastrointestinal (i.e. nausea, vomiting, mucositis and diarrhoea), were significantly lower in FLAI arm. In both arms, relapses were more frequent in patients who were not submitted to allo-SCT. After a median follow-up of 17 months, 30% and 38% of the patients are in continuous CR in FLAI and ICE arm respectively. Our prospective randomised study confirmed the anti-leukaemic effect and the low toxic profile of FLAI as induction treatment for newly diagnosed AML patients.  相似文献   
7.
An ultrasound-guided double pass biopsy technique using a large bore cutting needle via an anterior subcostal route (USAB) is described. The diagnostic adequacy of this biopsy procedure was evaluated in comparison with the traditional Menghini technique in 200 cases of suspected chronic liver disease randomly assigned to the two different procedures. Retrieval rate was better in the USAB group. The sample length was less than 15 mm in four cases in the USAB group and in 19 cases in the Menghini group. In three cases in the USAB group the second pass modified the diagnosis of the first specimen from chronic active hepatitis to active cirrhosis. In order to evaluate the safety and discomfort of the two procedures 340 patients assigned to the different techniques had liver ultrasound scans 6 and 24 h following percutaneous biopsy. USAB was associated with a reduced frequency of complications (one out of 170 patients vs. seven out of 170 patients who had the intercostal Menghini procedure). In our study, USAB seems to offer better sampling and size of individual samples, together with reduced frequency of major and minor complications.  相似文献   
8.
Reduced left ventricular function and ventricular arrhythmias are the main risk factors associated with sudden death in patients with previous acute myocardial infarction. Antiarrhythmic therapy may have side-effects on myocardial contractility and sometimes makes the arrhythmia itself worse, especially when the pump function is seriously compromised. The aim of this study was to evaluate the efficacy of oral mexiletine as well as any modifications in left ventricular function by means of ambulatory ECG monitoring and angiocardiography with Tc 99m, at rest and after the handgrip test, in 20 patients with previous myocardial infarction and ventricular arrhythmias who were grouped into NYHA class II and class III. The mexiletine therapy lasted three weeks. Both classes showed a significant decrease in the number of ventricular extrasystoles/hour and in the number of couples (p less than 0.01). The decrease in the number of the ventricular runs proved to be higher in the general analysis (p less than 0.01) than in each NYHA class (p less than 0.05). At the end of the study, significant modifications were not observed either in the end-diastolic and end-systolic volumes, or in the ventricular ejection fraction.  相似文献   
9.
10.
Multisite near infrared spectroscopy (NIRS) monitoring during pediatric cardiopulmonary bypass (CPB) has not been extensively validated. Although it might be rational to explore regional tissue saturation at different body sites (namely brain, kidney, upper body, lower body), conflicting results are currently provided by experience in children. The aim of our study was to evaluate absolute values of multisite NIRS saturation during CPB in a cohort of infants undergoing pediatric cardiac surgery to describe average differences between cerebral, renal, upper body (arm), and lower body (thigh) regional saturation. Furthermore, the correlation between cerebral NIRS and cardiac index (CI) at CPB weaning was evaluated. Twenty‐five infants were enrolled: their median weight, age, and body surface area were 3.9 (3.3–6) kg, 111 (47–203) days, and 0.24 (0.22–0.33) m2, respectively. Median Aristotle score was 8 (6–10), and vasoactive inotropic score at CPB weaning was 16 (14–25). A total of 17 430 data points were recorded by each sensor: two‐way ANOVA showed that time (P < 0.0001) and site (P = 0.0001) significantly affected variations of NIRS values: however, if cerebral NIRS values are excluded, sensor site is no more significant (P = 0.184 in the no circulatory arrest [noCA] group and P = 0.42 in the circulatory arrest [CA] group). Analysis of NIRS saturation changes over time showed that, at all sites, average NIRS values increased after CPB start, even if the increase of cerebral saturation was less intense than other sites (P < 0.0001). Detailed analysis of interaction between site of NIRS measurement and time point showed that cerebral NIRS (ranging from 65 to 75%) was always significantly lower than that of other channels (P < 0.0001) that tended to be in the range of oversaturation (80–90%), especially during the CPB phase. Average cerebral NIRS values of patients who did not undergo circulatory arrest (CA) during CPB, 10 min after CPB weaning, were associated with average CI values with a significant correlation (r = 0.7, P = 0.003). In conclusion, during CPB, cerebral NIRS values are expected to remain constantly lower than somatic sensors, which instead tend to show similar elevated saturations, regardless of their position. Based on these results, positioning of noncerebral NIRS sensors during CPB without CA may be questioned.  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