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   1155篇
  免费   89篇
  国内免费   63篇
耳鼻咽喉   6篇
儿科学   51篇
妇产科学   7篇
基础医学   129篇
口腔科学   34篇
临床医学   115篇
内科学   221篇
皮肤病学   24篇
神经病学   40篇
特种医学   266篇
外科学   107篇
综合类   58篇
预防医学   68篇
眼科学   8篇
药学   110篇
肿瘤学   63篇
  2023年   5篇
  2022年   6篇
  2021年   18篇
  2020年   7篇
  2019年   7篇
  2018年   14篇
  2017年   11篇
  2016年   19篇
  2015年   12篇
  2014年   22篇
  2013年   21篇
  2012年   19篇
  2011年   23篇
  2010年   28篇
  2009年   32篇
  2008年   20篇
  2007年   44篇
  2006年   33篇
  2005年   38篇
  2004年   22篇
  2003年   21篇
  2002年   25篇
  2001年   27篇
  2000年   21篇
  1999年   33篇
  1998年   62篇
  1997年   64篇
  1996年   58篇
  1995年   61篇
  1994年   39篇
  1993年   44篇
  1992年   20篇
  1991年   28篇
  1990年   27篇
  1989年   51篇
  1988年   41篇
  1987年   36篇
  1986年   21篇
  1985年   32篇
  1984年   16篇
  1983年   13篇
  1982年   16篇
  1981年   23篇
  1980年   22篇
  1979年   19篇
  1978年   9篇
  1977年   23篇
  1976年   15篇
  1975年   13篇
  1973年   6篇
排序方式: 共有1307条查询结果,搜索用时 0 毫秒
11.
12.
13.
锌酞菁脂质体光动力作用引起小鼠肿瘤的细胞程序性死亡   总被引:3,自引:1,他引:3  
电镜观察了锌酞菁脂质体光动力作用引起小鼠MS-2纤维肉瘤的形态学变化。发现其作用很强,并对肿瘤细胞有明显的直接影响。肿瘤细胞的结构表现出明显的程序性细胞死亡(apoptosis,programmedceldeath)的特点:胞核染色质凝聚边集、核固缩、核破裂、染色质凝块流失、胞质内吞噬现象、胞膜表面肿胀粗钝的胞突形成、细胞碎裂等。加深了对锌酞菁脂质体光敏作用机理的认识,但其详细的发生机制和调节途径有待阐明。  相似文献   
14.
The purpose of this study was to describe the toxicity of concurrent standard dose adjuvant radiation therapy (RT) and paclitaxel in a series of patients receiving primary breast cancer therapy. From June 1998 to April 1999, 20 patients with breast cancer received concurrent adjuvant radiation and paclitaxel. There were 16 patients (80%) with American Joint Committee on Cancer (AJCC) stage II disease and 4 with stage III disease. Eighteen patients, 12 postmastectomy and 6 breast conservation, were treated with definitive surgery followed by concurrent RT and paclitaxel. Two received concurrent neoadjuvant radiation and paclitaxel. All patients received a doxorubicin-containing combination prior to radiation and paclitaxel. RT was delivered concurrently with paclitaxel after the completion of all doxorubicin therapy, with all patients receiving at least two cycles of paclitaxel (175 mg/m 2) every 3 weeks during RT. Toxicity was graded weekly according to Radiation Therapy Oncology Group criteria. Thirteen patients (65%) developed grade 2 or higher cutaneous toxicity. In the postmastectomy group, 6 of 12 patients (50%) developed grade 2 cutaneous toxicity, and 4 of 12 patients (33%) developed grade 3. RT was discontinued in 1 and placed on hold in 3 of these patients. In the breast-conservation group, 2 of 6 patients (33%) developed grade 3 toxicity. In the neoadjuvant group, 1 of 2 patients (50%) developed grade 3 toxicity. Four patients (20%) developed radiation pneumonitis, 2 of 12 (17%) in the postmastectomy group and 2 of 6 (33%) in the breast conservation group, with 2 requiring hospitalization and 1 a diagnostic open-lung biopsy. In this group of patients, standard dose concurrent radiation and paclitaxel resulted in a high incidence of cutaneous and pulmonary toxicity. Concurrent radiation and paclitaxel with these doses and schedule should be approached cautiously until further studies documenting its safety are completed.  相似文献   
15.
SUMMARY BACKGROUND DATA: Previous studies have suggested a variety of factors that may affect the false negative (FN) rate for sentinel lymph node (SLN) biopsy in breast cancer. Because FN results are relatively rare, no prior studies have had sufficient sample size to allow detailed statistical analysis of factors predicting FN results. METHODS: Patients with clinical stage T1-2, N0 invasive breast cancer were enrolled in a prospective, multicenter study. All patients underwent SLN biopsy, followed by planned completion axillary dissection regardless of the SLN results, to assess the FN rate. SLN biopsy was performed using radioactive colloid injection in combination with isosulfan blue dye in 94% of cases. Dermal, subdermal, peritumoral, or subareolar radioactive colloid injection techniques were used at the discretion of each institution. Univariate and multivariate analyses were performed to identify factors associated with a FN result. RESULTS: SLNs were identified in 3870 of 4117 patients (94%). There were 1243 true positive, 2521 true negative, and 106 FN results. Age, histologic subtype, the number of non-SLN removed, tumor palpability, type of breast biopsy, and SLN injection technique were not significant factors. On multivariate analysis, tumor size <2.5 cm, upper outer quadrant tumor location, removal of only a single SLN, minimal surgeon experience, presence of a single positive axillary LN, and use of immunohistochemistry (IHC) for SLN analysis were independently associated with an increased risk of FN results. CONCLUSIONS: Surgeon experience, tumor size and location, and the number of SLN removed are preoperative and intraoperative factors that independently predict the risk of a FN result. In contrast to suggestions from other smaller studies, age does not affect the likelihood of a FN result; a lesser, rather than greater, number of positive axillary nodes was associated with an increased likelihood of a FN result; and IHC analysis of the SLN increases, rather than decreases, the risk of FN results.  相似文献   
16.
17.
Two children are reported in whom intestinal pseudo-obstruction was the initial manifestation of systemic sclerosis. Gastrointestinal symptoms and skin changes resolved or improved in both children following treatment with prednisone and penicillamine (case 1) or methotrexate (case 2), although radiological changes of the gastrointestinal tract persisted at 3 and 2 yr of follow-up, respectively.   相似文献   
18.
OBJECTIVE: To examine whether promoter polymorphisms associated with variation in interleukin-10 (IL-10) production are relevant to the development of rheumatoid arthritis (RA) or Felty's syndrome (FS). METHODS: DNA was obtained from 44 FS patients, 117 RA patients and 295 controls. The promoter region between -533 and - 1120 was amplified by polymerase chain reaction, and polymorphisms detected by restriction enzyme digest or sequence-specific oligonucleotide probing. RESULTS: We found no significant difference in allele or haplotype frequencies between the groups. CONCLUSION: There is no association between FS or RA and these recently identified IL-10 promoter polymorphisms. Other genetic or environmental factors could explain the alterations in IL-10 levels seen in these conditions.   相似文献   
19.
The recognition of cancer cells by T cells can impact upon prognosis and be exploited for immunotherapeutic approaches. This recognition depends on the specific interaction between antigens displayed on the surface of cancer cells and the T cell receptor (TCR), which is generated by somatic rearrangements of TCR α‐ and β‐chains (TCRb). Our aim was to assess whether ultra‐deep sequencing of the rearranged TCRb in DNA extracted from unfractionated clear cell renal cell carcinoma (ccRCC) samples can provide insights into the clonality and heterogeneity of intratumoural T cells in ccRCCs, a tumour type that can display extensive genetic intratumour heterogeneity (ITH). For this purpose, DNA was extracted from two to four tumour regions from each of four primary ccRCCs and was analysed by ultra‐deep TCR sequencing. In parallel, tumour infiltration by CD4, CD8 and Foxp3 regulatory T cells was evaluated by immunohistochemistry and correlated with TCR‐sequencing data. A polyclonal T cell repertoire with 367–16 289 (median 2394) unique TCRb sequences was identified per tumour region. The frequencies of the 100 most abundant T cell clones/tumour were poorly correlated between most regions (Pearson correlation coefficient, –0.218 to 0.465). 3–93% of these T cell clones were not detectable across all regions. Thus, the clonal composition of T cell populations can be heterogeneous across different regions of the same ccRCC. T cell ITH was higher in tumours pretreated with an mTOR inhibitor, which could suggest that therapy can influence adaptive tumour immunity. These data show that ultra‐deep TCR‐sequencing technology can be applied directly to DNA extracted from unfractionated tumour samples, allowing novel insights into the clonality of T cell populations in cancers. These were polyclonal and displayed ITH in ccRCC. TCRb sequencing may shed light on mechanisms of cancer immunity and the efficacy of immunotherapy approaches. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
20.
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