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   214篇
  免费   15篇
儿科学   5篇
妇产科学   1篇
基础医学   19篇
临床医学   11篇
内科学   88篇
皮肤病学   1篇
神经病学   9篇
特种医学   9篇
外科学   12篇
综合类   2篇
预防医学   3篇
眼科学   1篇
药学   8篇
肿瘤学   60篇
  2022年   3篇
  2021年   2篇
  2020年   7篇
  2019年   4篇
  2018年   5篇
  2017年   4篇
  2015年   2篇
  2014年   1篇
  2013年   2篇
  2012年   9篇
  2011年   5篇
  2009年   3篇
  2008年   5篇
  2007年   4篇
  2006年   3篇
  2005年   3篇
  2004年   4篇
  2003年   3篇
  2002年   2篇
  2000年   6篇
  1999年   8篇
  1998年   4篇
  1997年   4篇
  1996年   3篇
  1995年   3篇
  1994年   2篇
  1993年   6篇
  1992年   10篇
  1991年   10篇
  1990年   12篇
  1989年   10篇
  1988年   10篇
  1987年   11篇
  1986年   13篇
  1985年   4篇
  1984年   7篇
  1983年   6篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1979年   8篇
  1978年   3篇
  1977年   1篇
  1974年   1篇
  1967年   3篇
  1966年   1篇
  1965年   1篇
  1960年   2篇
排序方式: 共有229条查询结果,搜索用时 15 毫秒
81.
In this work, a method previously proposed in the literature (Sisto R, Pinto I, Stacchini N et al. Infrared radiation exposure in traditional glass factories. AIHAJ 2000; 61: 5-10) to evaluate the exposure to infrared (IR) radiation when the source can be approximated as a black body is implemented in a mathematical code developed in Matlab. Some practical situations are discussed. A comparison between the results obtained by a spectroradiometric technique and that obtained by using a broadband radiometer and the modelling of the source is shown. The IR radiation exposure evaluations in a cement industry and in a steel forge are shown and compared to the exposure limit values.  相似文献   
82.
83.
Sequence variation of the hypervariable segments (HVS) I/II of mitochondrial DNA (mtDNA) and the haplogroup affiliation were determined in a sample of 271 Italian subjects. This analysis showed that 42% of the individuals could be ascribed to H, the most frequent haplogroup in European Caucasian populations. This fraction was then screened for specific single nucleotide polymorphisms located in the coding region to identify H subclades H1–H15. We set up two multiplex polymerase chain reactions and specific SNaPshot assays to investigate the frequency distribution of these subgroups in our population sample and to examine their usefulness in discriminating among commonly shared HVS I/II sequences. This allowed the assignment of a large portion of the mtDNAs (∼70%) to specific subhaplogroups, with H1 and H5 being the most represented. About two-thirds of the individuals sharing common HVS I/II sequences were subdivided and ascribed to specific H subhaplogroups with a significant reduction of the frequencies of the most common mtDNA haplotypes. Haplogroup H subtyping could thus be extremely useful in forensic identification when many samples have to be analysed and compared, avoiding excessive time-consuming and labor-intensive sequencing analysis.  相似文献   
84.
The aim of this study was to assess the efficacy of percutaneous cementoplasty (PC) with polymethylmethacrylate (PMMA) in painful extravertebral lytic bone metastases not responding to conventional therapy. Fifty patients (25 females), mean age 64.7 ± 11.2 years, underwent PC after giving informed consent. Procedures were performed under fluoroscopy (1/50) or combined fluoroscopy-CT (49/50) guidance in local anesthesia or under deep sedation in 7 patients with large metastases who underwent radiofrequency thermoablation (RFA) in the same session. Seventy lesions were treated (1-6 per patient; average, 1.4 ± 0.9), arranging in size from 1 to 10 cm (average, 3.6 ± 2.1 cm). Mean volume of PMMA per lesion was 5.9 ± 3.2 ml (range, 1.5–15.0 ml). Pain was prospectively evaluated on an 11-point visual analog scale (VAS) before and after the procedure (follow-up, 15 to 36 months). Mean VAS score dropped from 9.1 ± 1.2 (range: 6–10) to 2.1 ± 2.5 (range: 0–9). Mean VAS difference was 7.0 ± 2.3 (range, 1–10; p < 0.0001, Wilcoxon signed rank test). Forty-seven of the 50 patients (94%) suspended narcotic drugs, in 22 (44%) pain was controlled with a nonsteroidal anti-inflammatory drug, in 25 (50%) analgesic therapy was suspended, and 13 of 50 (26%) had complete pain regression. In 3 of the 50 patients (6%) pain was not improved. No statistical difference between osteoplasty and osteoplasty plus RFA was found (p = 0.8338, Mann–Whitney test). No complications arose during the procedure. Two patients with metastases in the femoral diaphysis reported a fracture 1 month after treatment. PC is effective to obtain pain regression in painful bone metastases not responding to conventional analgesic therapy; bone consolidation cannot be obtained in the diaphysis of long weight-bearing bones.  相似文献   
85.
86.
The cytogenetic follow-up of a case of refractory anemia with excess of blasts (RAEB) that rapidly evolved to acute myeloblastic leukemia (Ml-FAB type) is described. Bone marrow analysis at presentation revealed two chromosomally abnormal clones that shared an interstitial deletion of the long arm of chromosome 5 (5q−) and a terminal deletion of the short arm of chromosome 12 (12p-), but that differed from one another in the localization of a very similar segment of chromosome 17 (i.e. 17q11−12qter) on two clearly distinct karyotypic sites: 2q37 and 17q25. Fourteen percent of the metaphases examined bore the 2q+ marker and 38% the 17q+ marker; the remaining cells had a normal karyotype. A second study carried out 4 months later, at onset of the acute phase, revealed that the clone with normal karyotype had almost completely disappeared and that there had been an inversion in the ratio of the two abnormal cell populations. In the final study, made 1 month before death, the cells with t(2;17) had totally effaced the other clone. These findings seem to indicate that, among the karyotypic changes that occurred in an original clone with 5q− and 12p−, only the t(2;17) could have played a crucial role in the final leukemic transformation.  相似文献   
87.
Human follicular B-cell lymphomas possess a t(14;18) that translocates a putative protooncogene, BCL2, into the immunoglobulin heavy chain locus. The normal BCL2 gene is quiescent in resting B cells, expressed in proliferating, but down-regulated in differentiated B cells. Inappropriately high levels of BCL2-immunoglobulin chimeric RNA are present in t(14;18) lymphomas for their mature B-cell stage. We examined the biologic effects of BCL2 deregulation in human B cells by introducing BCL2 into human B-lymphoblastoid cell lines (LCLs) with retroviral gene transfer. Although deregulated BCL2 expression as a single agent was not sufficient to confer tumorigenicity to LCLs, it consistently produced a 3- to 4-fold increment in LCL clonogenicity in soft agar. In addition, BCL2 deregulation complements the transforming effects of the MYC oncogene in LCLs. BCL2 augmented the clonogenicity of LCLs bearing exogenous MYC and increased the frequency and shortened the latency of tumor induction in immunodeficient mice. These results demonstrate a role for BCL2 as a protooncogene that affects B-cell growth and enhances B-cell neoplasia.  相似文献   
88.
89.
90.
Seventy-six patients with primary gastric non-Hodgkin's lymphomas (PGL) were diagnosed, and 75 were treated between 1975 and 1985. According to the Working Formulation 22 patients had low-grade malignant histologic subtypes, 27 intermediate-grade, and 27 high-grade. Twenty-four cases were diagnosed by endoscopic biopsies, 52 through laparotomy biopsies. Forty-five underwent subtotal or total gastric resection; seven were considered unresectable at laparotomy; 23 did not undergo surgery because of the high operative risk, mainly due to advanced age and coexisting diseases; and one died of myocardial infarction a few days after admission, before starting therapy. All patients who did not undergo laparotomy were staged with bipedal lymphangiography or abdominal ultrasonography and/or computed tomography. Stage, evaluated according to the criteria of Musshoff, was I or II1 in 16 cases, II2 in five, and IV in the remaining 55. Treatment modalities included surgery (S), chemotherapy (CT), radiotherapy (RT), and combinations thereof in the following proportions: only S in ten cases, S + CT in 32 cases, S + RT in one case, S + CT + RT in two cases, CT only in 25 cases, CT + RT in five cases. No substantial differences in response to therapy and in survival were found in relation to the different treatments. Ten-year survival was 43% in Stage I or II and 20% in Stage IV. Of the 45 resected patients, five postoperative deaths were recorded (11%). No bleeding or perforations were observed in the 30 unresected patients, and survival of such cases compared with that of the resected ones. These findings, together with data from the literature, suggest that some of the advantages claimed for surgery in PGL (debulking and abatement of the risk of perforation or hemorrhage during CT or RT) have been overestimated in relation to the intrinsic surgical risk and to the possibility of anticancer therapy. Gastric resection may still be unavoidable as a diagnostic procedure in a minority of cases and may represent the primary therapeutic procedure in clinically assessed early-stage and low-risk patients, but it cannot be considered mandatory whenever possible merely for debulking purposes or to obviate possible perforation or hemorrhage. The CT and/or RT can be effective in unresected and even bulky cases, providing minimal risk of severe hemorrhage or perforation.  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