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   2213篇
  免费   73篇
  国内免费   6篇
耳鼻咽喉   24篇
儿科学   54篇
妇产科学   82篇
基础医学   250篇
口腔科学   35篇
临床医学   182篇
内科学   409篇
皮肤病学   21篇
神经病学   263篇
特种医学   97篇
外科学   314篇
综合类   12篇
一般理论   1篇
预防医学   142篇
眼科学   14篇
药学   197篇
中国医学   3篇
肿瘤学   192篇
  2021年   19篇
  2020年   23篇
  2019年   33篇
  2018年   24篇
  2017年   27篇
  2016年   35篇
  2015年   33篇
  2014年   58篇
  2013年   106篇
  2012年   128篇
  2011年   131篇
  2010年   104篇
  2009年   78篇
  2008年   121篇
  2007年   148篇
  2006年   120篇
  2005年   135篇
  2004年   144篇
  2003年   104篇
  2002年   128篇
  2001年   13篇
  2000年   14篇
  1999年   27篇
  1998年   23篇
  1997年   26篇
  1996年   22篇
  1995年   25篇
  1994年   31篇
  1993年   24篇
  1992年   20篇
  1991年   17篇
  1990年   20篇
  1989年   15篇
  1988年   13篇
  1986年   17篇
  1985年   16篇
  1984年   24篇
  1983年   12篇
  1982年   16篇
  1981年   25篇
  1980年   15篇
  1979年   13篇
  1978年   14篇
  1977年   14篇
  1976年   10篇
  1975年   15篇
  1974年   15篇
  1973年   14篇
  1972年   11篇
  1967年   11篇
排序方式: 共有2292条查询结果,搜索用时 31 毫秒
31.
PURPOSE: This Nordic multicenter phase II study evaluated the efficacy and safety of oxaliplatin combined with the Nordic bolus schedule of fluorouracil (FU) and folinic acid (FA) as first-line treatment in metastatic colorectal cancer. PATIENTS AND METHODS: Eighty-five patients were treated with oxaliplatin 85 mg/m(2) as a 2-hour infusion on day 1, followed by a 3-minute bolus injection with FU 500 mg/m(2) and, 30 minutes later, by a bolus injection with FA 60 mg/m(2) every second week. The same doses of FU and FA were also given on day 2. RESULTS: Fifty-one of 82 assessable patients achieved a complete (n = 4) or partial (n = 47) response, leading to a response rate of 62% (95% CI, 52% to 72%). Nineteen patients showed stable disease, and 12 patients had progressive disease. Thirty-eight of the 51 responses were radiologically confirmed 8 weeks later (confirmed response rate, 46%; 95% CI, 36% to 58%). The estimated median time to progression was 7.0 months (95% CI, 6.3 to 7.7 months), and the median overall survival was 16.1 months (95% CI, 12.7 to 19.6 months) in the intent-to-treat population. Neutropenia was the main adverse event, with grade 3 to 4 toxicity in 58% of patients. Febrile neutropenia developed in seven patients. Nonhematologic toxicity consisted mainly of neuropathy (grade 3 in 11 patients and grade 2 in another 27 patients). CONCLUSION: Oxaliplatin combined with the bolus Nordic schedule of FU+FA (Nordic FLOX) is a well-tolerated, effective, and feasible bolus schedule as first-line treatment of metastatic colorectal cancer that yields comparable results compared with more complex schedules.  相似文献   
32.
Background Duodenogastric reflux is known to cause an increased frequency of cancer in the glandular portion of the stomach in rats. Furthermore, it is debated whether inhibition of gastric acid secretion may promote gastric carcinogenesis. In the present study we examined the combined effect of gastroduodenal reflux and acid inhibition with respect to the development of gastric carcinoma in the rat.Methods Following the construction of a gastrojejunostomy in male Wistar rats, half of them were given the proton pump inhibitor lanzoprazole for 1 year. The rats were then killed and the pH in the stomach and gastrin in blood were measured. The stomach was examined macroscopically as well as histologically.Results Gastrin levels at autopsy were significantly increased in treated rats compared to the control group, confirming an effect of lanzoprazole on gastric acid secretion. Body weight was significantly reduced in the treated rats. Thirty of 79 rats developed gastric cancer, and they were all adenocarcinomas of the Lauren intestinal type. Gastric cancers occurred significantly more often in lanzoprazole-treated rats (50%) compared with controls (27%).Conclusion Lanzoprazole given orally enhances the carcinogenic effect of duodenogastric reflux in rats.  相似文献   
33.
PURPOSE: Renal cell carcinoma (RCC) is the most common malignancy of the kidney composed of specific tumor types. The sporadic conventional RCCs are, in contrast to the other RCC types, characterized by a high rate of von Hippel-Lindau (VHL) mutations and hypermethylation. The majority of these tumors lack functional VHL protein (pVHL) that leads to increased hypoxia-inducible factor 1alpha (HIF-1alpha) expression. The pVHL is the physiologic regulator of the activity of HIF-1alpha by targeting it to the proteasome for degradation under normoxia. Both pVHL and HIF-1alpha target other genes that are important for cancer survival and proliferation. Expression of HIF-1alpha has been linked to poor prognosis in different malignancies, although few studies have been done on the relation between HIF-1alpha and clinical variables in RCC. EXPERIMENTAL DESIGN: HIF-1alpha protein expression was analyzed in tumor tissue from 92 patients with RCC. HIF-1alpha was quantified by Western blot relative to a positive control. RESULTS: The HIF-1alpha protein was expressed as two bands which strongly correlated (r = 0.906, P < 0.001); therefore, they were added and the sum evaluated against clinicopathologic variables. There was no association between HIF-1alpha and gender, stage, grade, tumor size, or vein invasion. Conventional RCCs had significantly higher HIF-1alpha expression compared with papillary and chromophobe RCCs and kidney cortex. In conventional RCC, HIF-1alpha was an independent prognostic factor. CONCLUSION: HIF-1alpha levels varied significantly between the different RCC types. In conventional RCC, HIF-1alpha was an independent prognostic factor. These data indicate that HIF-1alpha is involved in tumorogenesis and progression of RCC. Evaluation of other HIF target gene products and correlation to angiogenesis seems warranted.  相似文献   
34.
OBJECTIVE: To evaluate serum parathyroid hormone-related protein (PTHrP) in relation to serum calcium and clinical outcome of patients with renal cell carcinoma. METHODS: Sera from 243 patients with renal cell carcinoma were collected prior to therapy. Serum PTHrP was analyzed using an immunoradiometric assay. Tumour stage, nuclear grade, corrected serum calcium, and survival were assessed. RESULTS: Serum PTHrP was detectable in 37/243 sera (15%) and hypercalcaemia (> or =2.60 mmol/l) in 32/220 (15%). A positive correlation between serum PTHrP and serum calcium was found (r = 0.326; p < 0.01). Following subdivision of the material, based on storage time, the frequency of detectable serum PTHrP seemed to decrease with time. Serum calcium, but not serum PTHrP, was correlated to tumour stage (p < 0.001). Survival was similar for patients with detectable and undetectable PTHrP, but those with hypercalcaemia had a significantly shorter survival time compared to those with normal serum calcium (p < 0.001). A multivariate analysis showed that tumour stage and serum calcium were independent prognostic factors, but not grade or PTHrP. CONCLUSIONS: A positive relation of serum PTHrP to serum calcium was demonstrated in patients with renal cell carcinoma. Hypercalcaemia but not serum PTHrP predicted a worse prognosis.  相似文献   
35.
The MYC genes are the most frequently activated oncogenes in human tumors and are hence attractive therapeutic targets. MYCN amplification leads to poor clinical outcome in childhood neuroblastoma, yet strategies to modulate the function of MYCN do not exist. Here we show that 10058-F4, a characterized c-MYC/Max inhibitor, also targets the MYCN/Max interaction, leading to cell cycle arrest, apoptosis, and neuronal differentiation in MYCN-amplified neuroblastoma cells and to increased survival of MYCN transgenic mice. We also report the discovery that inhibition of MYC is accompanied by accumulation of intracellular lipid droplets in tumor cells as a direct consequence of mitochondrial dysfunction. This study expands on the current knowledge of how MYC proteins control the metabolic reprogramming of cancer cells, especially highlighting lipid metabolism and the respiratory chain as important pathways involved in neuroblastoma pathogenesis. Together our data support direct MYC inhibition as a promising strategy for the treatment of MYC-driven tumors.  相似文献   
36.
The aim of this study is to describe the experience of time as it presents itself at the place being situated when living with severe incurable disease and receiving palliative care. The empirical data consist of 26 open‐ended interviews with 23 patients receiving palliative care at home, at a palliative day care, in a palliative bed unit in hospital or in a nursing home in Norway. A common meaning of a shifting space for living emerged from the analysis and was revealed through three different aspects: (i) Transition from a predictable to an unpredictable time: To live with severe incurable disease marks a transition to a changed life involving an ongoing weakened and altered body with bothersome symptoms making experience of time different and unpredictable. (ii) Transition between a safe and unsafe time: When time is unpredictable, feeling safe is revealed as essential to how time is experienced at the place being situated. (iii) To be in transition from a homely to a homeless existence: In a time of increased bodily weakness, unpredictable ailments and displacements, the sense of belonging to the place is revealed as significant to the experience of time. Not knowing where to be in a time of change is like an existential cry of distress where the foothold in existence is lost. The findings are discussed and interpreted as an embodied experience originating from the passage of time continually affecting life sometimes so fundamentally that it marks a transition to a changed space of life that is reflected in the experience of time.  相似文献   
37.
38.
39.
Objectiveto explore experiences with nutrition-related information during routine antenatal care among women of different ethnical backgrounds.Designindividual interviews with seventeen participants were conducted twice during pregnancy. Data collection and analysis were inspired by an interpretative phenomenological approach.Settingparticipants were purposively recruited at eight Mother and Child Health Centres in the area of Oslo, Norway, where they received antenatal care.Participantsparticipants had either immigrant backgrounds from African and Asian countries (n=12) or were ethnic Norwegian (n=5). Participants were pregnant with their first child and had a pre-pregnancy Body Mass Index above 25 kg/m2.Findingsparticipants experienced that they were provided with little nutrition-related information in antenatal care. The information was perceived as presented in very general terms and focused on food safety. Weight management and the long-term prevention of diet-related chronic diseases had hardly been discussed. Participants with immigrant backgrounds appeared to be confused about information given by the midwife which was incongruent with their original food culture. The participants were actively seeking for nutrition-related information and had to navigate between various sources of information.Conclusionsthe midwife is considered a trustworthy source of nutrition-related information. Therefore, antenatal care may have considerable potential to promote a healthy diet to pregnant women. Findings suggest that nutrition communication in antenatal care should be more tailored towards women's dietary habits and cultural background, nutritional knowledge as well as level of nutrition literacy.  相似文献   
40.
The objective of this study was to investigate social hearing in successful users of multichannel cochlear implants (CIs) and to compare the scores with those of a group of hearing-impaired adults using acoustical hearing aids (HAs). Out of 88 patients who had undergone surgery, 75 CI users with a mean age of 55 years and a mean pre-operative hearing level of 113dB in the better ear were compared with 59 users of acoustical HAs with a mean age of 56 years and a mean hearing level of 82dB in the better ear. Seven CI patients were non-users and were excluded from the study. The Performance Inventory for Profound and Severe Loss, a questionnaire that measures different aspects of hearing handicap, was used. The CI group scored significantly better than the HA group in three of six evaluated categories, measuring subjective intensity of sounds, speech with visual cues, and response to auditory failure. Awareness of environmental sounds, speech with no visual cues and personal reactions did not differ significantly. The group of successful CI users scored higher on a self-report measure than did a group of users of acoustical HAs with moderate- severe-profound deafness. The best CI users scored better than the best HA users, and the worst CI users scored worse than the worst HA users.  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