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   729篇
  免费   40篇
  国内免费   2篇
耳鼻咽喉   11篇
儿科学   26篇
妇产科学   8篇
基础医学   108篇
口腔科学   25篇
临床医学   53篇
内科学   208篇
皮肤病学   27篇
神经病学   64篇
特种医学   16篇
外科学   82篇
预防医学   52篇
眼科学   8篇
药学   29篇
肿瘤学   54篇
  2023年   1篇
  2022年   11篇
  2021年   30篇
  2020年   13篇
  2019年   26篇
  2018年   19篇
  2017年   11篇
  2016年   16篇
  2015年   25篇
  2014年   27篇
  2013年   45篇
  2012年   51篇
  2011年   57篇
  2010年   35篇
  2009年   29篇
  2008年   41篇
  2007年   38篇
  2006年   56篇
  2005年   53篇
  2004年   54篇
  2003年   39篇
  2002年   26篇
  2001年   2篇
  2000年   6篇
  1999年   7篇
  1998年   4篇
  1997年   8篇
  1996年   10篇
  1995年   5篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   2篇
  1977年   1篇
  1947年   1篇
排序方式: 共有771条查询结果,搜索用时 15 毫秒
51.
Pilomatrixial carcinoma is the malignant variety of pilomatrixoma. It is a malignant lesion, locally aggressive that can reappear, specially if not completely removed. Scanty are the number of cases listed in the literature (2). Although metastases are uncommon one or twice references can be found in the writings (1). We report 2 cases of pilomatrixial carcinoma located in the middle canthal and malar zones, which were treated surgically: excision of the tumor and reconstruction by means of a local rotation flap.  相似文献   
52.
It is currently unclear whether any combination therapy for the treatment of metastatic melanoma is superior to standard single-agent dacarbazine (DTIC) in terms of tumour response and overall survival. The available randomized clinical trial data were combined in a meta-analysis to address this question. Initially a thorough MEDLARS search was conducted covering the time period from January 1970 to January 1999. This literature search was supplemented by manual searches of study bibliographies (including review articles) and review of relevant textbooks. The meta-analysis was performed according to a prospective protocol using strict study eligibility criteria. Data derived from randomized controlled trials comparing single-agent DTIC with combination chemo/immunotherapy were combined using a fixed effects model. Data were stratified into three combination therapy groups: DTIC-containing regimens, non-DTIC-containing therapy, and chemotherapy plus immunotherapy. The primary outcome of interest was the proportion of patients demonstrating a complete or partial response to treatment. A total of 20 randomized trials comprising 3273 patients were initially combined in a meta-analysis. This yielded an odds ratio (OR) of 1.23 (95% confidence interval [CI] 1.02-1.48), demonstrating that combination drug therapies are associated with a 23% increase in response rate compared with single-agent DTIC. The combination of DTIC plus interferon-alpha produced a tumour response rate 53% greater (95% CI 1.10-2.13) than that seen with DTIC alone. This increase was greater than that seen with DTIC-containing multi-drug regimens, which had an OR of 1.33 (95% CI 0.99-1.78). No difference in overall survival was demonstrated. Non-DTIC-containing treatment programmes showed no advantage over DTIC in terms of tumour response rate (OR = 0.77, 95% CI 0.45-1.32). The combination of DTIC and interferon-alpha appears more active than standard single-agent DTIC in metastatic melanoma. Further randomized clinical trials employing a DTIC plus interferon arm are necessary to confirm these results.  相似文献   
53.
We investigated to what extent patients with variant angina and significant coronary stenosis (>or=70%) present a clinical and angiographic profile similar to patients with ST elevation myocardial infarction. Thus, the clinical and angiographic features as well as follow-up events of 200 patients were prospectively analyzed and were compared with those of 422 patients with a first ST elevation myocardial infarction survivors of the early phase (3 days) and those of 70 patients with variant angina and non significant stenosis. Age and incidence of smoking, systemic hypertension, diabetes and maximum ST elevation were similar in the 2 groups. Furthermore, among patients with significant coronary stenosis, stenosis severity and the proportion of eccentric lesions were also comparable. Incidence of recent-within 30 days prior to admission-angina at rest was higher in variant angina patients with significant stenosis (67% vs. 27%, p<0.001) than in those with myocardial infarction but long standing angina at rest (>30 days) was low and comparable in these 2 groups (15% vs. 11%, ns). Also, in a 5-year follow-up most patients from these 2 groups were free from angina at rest (86% vs. 84%) which in variant angina patients was largely attributable to a high revascularization rate (72%). Moreover, the rate of myocardial infarction/cardiac death (20% vs. 19%) was also similar. Patients with variant angina and non-significant stenosis, however, had longer antecedent angina, more frequent follow-up angina and a lower incidence of cardiac events than the other 2 groups. Thus, these findings suggest that patients with variant angina and significant coronary stenosis generally behave as an acute coronary syndrome-likely associated with an acutely complicated plaque-rather than as recurrent vasospastic angina, and should be managed accordingly.  相似文献   
54.
Allogeneic hematopoietic stem cell transplantation is the only curative therapy for myelodysplasia (MDS). To identify factors influencing transplantation outcome, we studied 452 recipients of HLA-identical sibling transplants for MDS from 1989 to 1997, reported to the International Bone Marrow Transplant Registry. Patients with treatment-related MDS or unclassified MDS were excluded. Median age was 38 years (range, 2-64 years). Sixty percent had refractory anemia with excess blasts (n = 136) or with excess blasts in transformation (n = 136). Conditioning regimens included total body irradiation in 199 (44%) cases. Marrow was T-cell depleted for 58 (13%) transplants. Cumulative incidences of neutrophil engraftment, grades II-IV acute graft-versus-host disease (GVHD), and chronic GVHD were 91% (95% confidence interval [CI], 88%-93%), 36% (95% CI, 31%-40%), and 39% (95% CI, 33%-44%), respectively. Three-year transplantation-related mortality (TRM), relapse, disease-free survival, and overall survival rates were 37% (95% CI, 32%-42%), 23% (95% CI, 19%-27%), 40% (95% CI, 36%-45%), and 42% (95% CI, 37%-47%), respectively. Multivariate analyses showed that young age and platelet counts higher than 100 x 10(9)/L at transplantation were associated with lower TRM and higher disease-free and overall survival rates. Relapse incidence was higher in patients with high percentages of blasts in the marrow at transplantation or presentation, with high International Prognostic Scoring System scores at diagnosis, and with T-cell-depleted transplants. These findings indicate that transplantation from an HLA-identical sibling offers the possibility of long-term, disease-free survival to patients with MDS. Best candidates are younger patients with a low percentage of blasts and preserved platelet counts.  相似文献   
55.
56.
AIM: The evolution of performance status, disability, and quality of life (QL) according to the Hebrew Rehabilitation Center for Aged QL (HRCA-QL) index for cancer patients through their terminal period is described. The assessment of HRCA-QL validity and reliability is also described. DESIGN: A total of 200 cancer patients were followed up from the onset of their "terminal phase" until they died. Information on symptoms, performance, disability and QL were collected by patient's oncologists in hospital and by their family practitioners and community nurses when the patient was at home. Health measures were: the HRCA-QL index, Karnofsky performance status (KPS) and the Independence in Activities of Daily Living (IADL) index. RESULTS: The three indices were acceptable for a fair number of patients at the start of the terminal phase. Almost two-thirds had a KPS > or =60. With respect to the IADL index, the patients were independent in five of the six functions, with 80% having a HRCA-QL equal to or greater than 4. The median duration of the terminal period was 59 days. All three indices declined progressively, with marked deterioration in the last 2 weeks. The HRCA-QL index was highly correlated with KPS and the IADL index, had good internal consistency and showed an acceptable test-retest and inter-rater reliability. The HRCA-QL index was reactive to clinical changes. CONCLUSIONS: All three scales confirmed that terminal patients experience a progressive loss of performance, increase in dependence and deterioration of QL as they approach the end of life. Based in these results, we consider the HTCA-QL index valid for use in terminal cancer patients.  相似文献   
57.
This paper presents a gender-classification schema based on online handwriting. Using samples acquired with a digital tablet that captures the dynamics of the writing, it classifies the writer as a male or a female. The method proposed is allographic, regarding strokes as the structural units of handwriting. Strokes performed while the writing device is not exerting any pressure on the writing surface, pen-up (in-air) strokes, are also taken into account. The method is also text-dependent meaning that training and testing is done with exactly the same text. Text-dependency allows classification be performed with very small amounts of text. Experimentation, performed with samples from the BiosecurID database, yields results that fall in the range of the classification averages expected from human judges. With only four repetitions of a single uppercase word, the average rate of well-classified writers is 68 %; with sixteen words, the rate rises to an average of 72.6 %. Statistical analysis reveals that the aforementioned rates are highly significant. In order to explore the classification potential of the pen-up strokes, these are also considered. Although in this case, results are not conclusive, and an outstanding average of 74 % of well-classified writers is obtained when information from pen-up strokes is combined with information from pen-down ones.  相似文献   
58.
59.
60.
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