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   5733篇
  免费   464篇
  国内免费   150篇
耳鼻咽喉   98篇
儿科学   287篇
妇产科学   224篇
基础医学   692篇
口腔科学   68篇
临床医学   632篇
内科学   1152篇
皮肤病学   131篇
神经病学   418篇
特种医学   467篇
外科学   582篇
综合类   165篇
一般理论   2篇
预防医学   427篇
眼科学   110篇
药学   387篇
  1篇
中国医学   4篇
肿瘤学   500篇
  2022年   23篇
  2021年   49篇
  2020年   46篇
  2019年   70篇
  2018年   89篇
  2017年   58篇
  2016年   102篇
  2015年   97篇
  2014年   124篇
  2013年   193篇
  2012年   243篇
  2011年   268篇
  2010年   173篇
  2009年   168篇
  2008年   271篇
  2007年   403篇
  2006年   272篇
  2005年   286篇
  2004年   234篇
  2003年   229篇
  2002年   212篇
  2001年   177篇
  2000年   156篇
  1999年   156篇
  1998年   133篇
  1997年   133篇
  1996年   113篇
  1995年   116篇
  1994年   84篇
  1993年   96篇
  1992年   104篇
  1991年   148篇
  1990年   104篇
  1989年   123篇
  1988年   108篇
  1987年   101篇
  1986年   77篇
  1985年   77篇
  1984年   72篇
  1983年   49篇
  1982年   59篇
  1981年   46篇
  1980年   40篇
  1979年   48篇
  1978年   39篇
  1977年   41篇
  1976年   44篇
  1975年   35篇
  1973年   30篇
  1972年   39篇
排序方式: 共有6347条查询结果,搜索用时 0 毫秒
51.
Improving the quality of care for patients with chronic illness has become a high priority. Implementing training programs in disease management (DM) so the next generation of physicians can manage chronic illness more effectively is challenging. Residency training programs have no specific mandate to implement DM training. Additional barriers at the training facility include: 1) lack of a population-based perspective for service delivery; 2) weak support for self-management of illness; 3) incomplete implementation due to physician resistance or inertia; and 4) few incentives to change practices and behaviors. In order to overcome these barriers, training programs must take the initiative to implement DM training that addresses each of these issues. We report the implementation of a chronic illness management curriculum based on the Improving Chronic Illness Care (ICIC) Model. Features of this process included both patient care and learner objectives. These were: development of a multidisciplinary diabetes DM team; development of a patient registry; development of diabetes teaching clinics in the family practice center (nutrition, general management classes, and one-on-one teaching); development of a group visit model; and training the residents in the elements of the ICIC Model, ie, the community, the health system, self-management support, delivery system design, decision support, and clinical information systems. Barriers to implementing these curricular changes were: the development of a patient registry; buy-in from faculty, residents, clinic leadership, staff, and patients for the chronic care model; the ability to bill for services and maintain clinical productivity; and support from the health system key stakeholders for sustainability. Unique features of each training site will dictate differences in emphasis and structure; however, the core principles of the ICIC Model in enhancing self-management may be generalized to all sites.  相似文献   
52.
Trezies AJ  Davis TR  Barton NJ 《Injury》2000,31(8):605-607
The results of a consecutive series of bone-grafting procedures for non-union of scaphoid fractures were assessed in order to investigate whether the patient's age or the delay between acute fracture and bone-graft surgery influenced the outcome. One hundred and thirty-four patients with a mean follow up of 2.6 years from bone-graft surgery for scaphoid fracture non-union were assessed for post-operative pain and radiographic evidence of union. No association was found between the union rate following surgery and either the patients' ages or the interval between the original injury and subsequent non-union surgery.  相似文献   
53.
OBJECTIVES: To test the hypothesis that meningococcal septicemia-related pulmonary edema is associated with a systemic abnormality of epithelial sodium and chloride transport and to investigate an association with hormones regulating Na transport. DESIGN: Prospective observational study. SETTING: The 24-bed pediatric intensive care unit and pediatric wards of Royal Liverpool Children's Hospital. PATIENTS: Consecutive children admitted to the pediatric intensive care unit and pediatric wards with a diagnosis of meningococcal septicemia and children (controls) with noninfectious critical illness receiving ventilatory support in the pediatric intensive care unit. MEASUREMENTS AND MAIN RESULTS: We measured sweat and saliva electrolytes, renal electrolyte excretion, nasal potential difference, and aldosterone, thyroxine, and cortisol levels. Pulmonary edema was diagnosed by chest radiography and its severity quantified by calculation of ventilation index at admission and duration of mechanical ventilation. We recruited 17 patients with severe meningococcal septicemia (nine patients with pulmonary edema), 14 patients with mild meningococcal septicemia, and 20 controls. Sweat and saliva Na and Cl concentrations and renal Na excretion were significantly (p < .05) higher in patients with pulmonary edema compared with controls. Nasal potential difference and amiloride response in patients with pulmonary edema were not significantly different to controls, but response to a low Cl solution was reduced in the nasal airway of patients with pulmonary edema (p < .05). Sweat and saliva chloride concentrations correlated significantly and better with ventilation index and duration of ventilation than sodium concentrations. Aldosterone, thyroxine, and cortisol levels were not significantly different between groups. CONCLUSIONS: We have confirmed that meningococcal septicemia-related pulmonary edema is associated with reduced systemic sodium and chloride transport. Features of reduced Cl transport were most closely associated with markers of respiratory compromise, and this was supported by the reduced chloride channel function detected on nasal potential difference measurement.  相似文献   
54.
Chemotherapy-induced ovarian failure: manifestations and management.   总被引:8,自引:0,他引:8  
Thanks to improvements in treatment regimens, more and more patients are now surviving cancer. However, cancer survivors are faced with the serious long-term effects of the different modalities of cancer treatments. One of these adverse effects is chemotherapy-induced irreversible damage to the ovarian tissues, which leads to premature ovarian failure and its resulting consequences such as hot flashes, osteoporosis, sexual dysfunction and the risk of infertility. Chemotherapy-induced ovarian failure (or chemotherapy-induced premature menopause) affects the quality of life of female cancer survivors. Although there is no clear definition of chemotherapy-induced ovarian failure, irreversible amenorrhoea lasting for several months (>12 months) following chemotherapy and a follicle stimulating hormone level of > or = 30 MIU/mL in the presence of a negative pregnancy test seems to be an appropriate characterisation. Different chemotherapy agents, alkylating cytotoxics in particular, have the potential to cause progressive and irreversible damage to the ovaries. The result of this damage is a state of premature ovarian failure, with progressive declining of estrogen levels, decreasing bone mass and an increased risk of fractures. Historically, hormonal replacement therapy (HRT) has been used to treat menopausal problems in the general population, but concerns about the potential of estrogen to increase the risk of breast cancer in women at high-risk or increase the risk of recurrence in cancer survivors, have forced physicians to utilise alternative treatments. This review discusses some of the newer therapies that are now available to provide appropriate symptom control, avoid complications such as fractures and possibly prevent infertility by making the ovarian epithelium less susceptible to cytotoxic agents.  相似文献   
55.
Polymorphisms in XPD exons 10 and 23 and bladder cancer risk.   总被引:3,自引:0,他引:3  
INTRODUCTION: The nucleotide excision repair gene, xeroderma pigmentosum complementation group D (XPD), has been hypothesized to have a role in cancer risk, but results from prior molecular epidemiologic studies and genotype-phenotype analyses are conflicting. MATERIALS AND METHODS: We examined the frequency of the XPD Asp312Asn polymorphism in exon 10 and the XPD Lys751Gln polymorphism in exon 23 in 505 incident bladder cancer cases and 486 healthy controls. RESULTS: Overall, the XPD exon 10 and 23 genotypes were not associated with bladder cancer risk, after adjusting for age, sex, ethnicity, and smoking status. A gender-specific role was evident that showed an increased risk for women, but not for men, associated with the variant genotypes for both exons. For example, when the exon 23 variant allele genotypes were combined (Lys/Gln + Gln/Gln), there was an increased bladder cancer risk in women [odds ratio (OR), 1.69; 95% confidence interval (95% CI), 1.12-2.58] but not in men (OR, 0.99; 95% CI, 0.79-1.24; P(interaction) = 0.041; OR, 1.62; 95% CI, 1.02-2.58). There was also a gene-smoking interaction that showed the variant alleles for either exon or the combination of both increase the risk of bladder cancer for light and heavy smokers. For exon 23 (P(interaction) = 0.057; OR, 1.21; 95% CI, 0.99-1.47), heavy smokers (> or = 20 pack-years) who carried the exon 23 variant allele genotypes had an OR of 4.13 (95% CI, 2.53-6.73), whereas heavy smokers with the wild-type genotypes were at lower risk (OR, 3.55; 95% CI, 2.19-5.75). Moderate smokers (1-19 pack-years) with the variant allele genotypes had an OR of 1.54 (95% CI, 0.94-2.53), whereas moderate smokers with the wild-type genotypes had an OR of 1.12 (95% CI, 0.63-1.98). CONCLUSIONS: Although we did not observe main effects associated with the XPD genotypes, these results do suggest the variant allele genotypes were associated with increased bladder cancer risk in women and smokers with statistically significant interactions in the exon 23 polymorphism. Although there is biological plausibility, these novel findings for gender and smoking should be interpreted with caution upon confirmation in larger studies.  相似文献   
56.
PURPOSE: To determine the antileukemic activity of weekly oral aminopterin in patients with refractory acute leukemia; to describe the pharmacodynamic properties of aminopterin; and to contrast the intracellular metabolism of aminopterin and methotrexate by patients' blasts in vitro. EXPERIMENTAL DESIGN: Forty-six patients were enrolled in three strata: children with acute lymphoblastic leukemia (ALL), adults with ALL, and patients with acute myeloid leukemia (AML). Aminopterin was given weekly, in two doses of 2 mg/m(2), 12 hours apart. Limited sampling pharmacokinetic analysis was done during the first week of therapy. Accumulation of [(3)H]aminopterin and [(3)H]methotrexate by leukemic blasts was studied in vitro. RESULTS: Six of 22 children with ALL (27%; 95% confidence interval, 8-47%) had clinically significant responses. None of those with AML and only two of 11 adults with ALL had responses meeting protocol definitions, although peripheral blast counts tended to decrease with therapy in all groups. Mucosal toxicity was minimal, even with limited use of leucovorin rescue. Complete bioavailability of aminopterin was confirmed, with a mean area under the curve of 0.52 +/- 0.03 micromol hour/L after oral dosing. No relationship between aminopterin pharmacokinetics and response was seen. In vitro, aminopterin showed more consistent metabolism by leukemic blasts to polyglutamates than methotrexate. Lineage-specific differences in the pattern of intracellular antifolylpolyglutamates were observed. CONCLUSIONS: Weekly oral aminopterin has significant activity among children with refractory ALL. With greater cellular accumulation and metabolism, more reliable bioavailability than methotrexate, and tolerable toxicity at this dose and schedule, aminopterin deserves further study as a potent alternative to methotrexate.  相似文献   
57.
58.
Multiple myeloma (MM) is an acquired malignant plasma cell disorder that develops late in life. Although progression free and overall survival has improved across all age, race, and ethnic groups, a subset of patients have suboptimal outcomes and are labeled as having high risk disease. A uniform approach to risk in NDMM remains elusive despite several validated risk stratification systems in clinical use. While we attempt to capture risk at diagnosis, the reality is that many important prognostic characteristics remain ill-defined as some patients relapse early who were defined as low risk based on their genomic profile at diagnosis. It is critical to establish a definition of high risk disease in order to move towards risk-adapted treatment approaches. Defining risk at diagnosis is important to both effectively design future clinical trials and guide which clinical data is needed in routine practice. The goal of this review paper is to summarize and compare the various established risk stratification systems, go beyond the R-ISS and international myeloma working group risk stratifications to evaluate specific molecular and cytogenetic abnormalities and how they impact prognosis independently. In addition, we explore the wealth of new genomic information from recent whole genome/exome sequencing as well as gene expression data and review known clinical factors affecting outcome such as disease burden and early relapse as well as patient related factors such as race. Finally, we provide an outlook on developing a new high risk model system and how we might make sense of co-occurrences, oncogenic dependencies, and mutually exclusive mutations.Subject terms: Myeloma, Genetic translocation, Risk factors, Cancer genetics  相似文献   
59.

Background

The cost of opiate substitution is usually considered lower in cost when methadone is used, as compared to that of buprenorphine, however the overall cost effectiveness of substitution programmes comparing the two drugs remains largely unknown.

Methods

We evaluated the treatment cost and effectiveness of methadone and buprenorphine when used in an opiate substitution programme in Norfolk, UK. All programme costs, estimated from the perspective of the drug treatment clinic, were collected on 361 opiate-dependent participants over a six-month period. Total costs comprised medication (methadone or buprenorphine) costs, pharmacy supervision and dispensing costs, and drug service clinic costs. Effectiveness was measured in terms of (1) each programmes ability to retain participants in the programme for six months, and (2) the ability of the programme to accomplish complete abstinence from illicit opiate consumption.

Results

Overall, mean medication-only costs of methadone were lower than that of buprenorphine, however, pharmacy and clinic costs were lower for the buprenorphine programme. The covariate-adjusted mean total cost of the two programmes was not significantly different. Mean six-month retention rates were higher on the methadone programme, therefore, the methadone programme “dominates” the buprenorphine programme as it was slightly more effective for the same cost. Conversely, when ability to stop taking illicit opiates concomitant with opiate substitution medication was considered, the buprenorphine programme was more effective with an additional cost of £903 per individual who stopped illicit opiate use.

Conclusions

The provision of buprenorphine should be considered an appropriate treatment if cessation of illicit opiate use, concomitant with programme retention is considered an important outcome.  相似文献   
60.
Twelve premature infants with significant apnea of prematurity while receiving therapeutic doses of aminophylline were given an intravenous infusion of doxapram, 2 or 2.5 mg/kg/hr. The ventilatory effects of the medication were monitored by means of face mask spirometry and airway occlusion studies. Doxapram therapy was associated with significant increases in minute ventilation, tidal volume, mean inspiratory flow, and airway pressure 100 msec after occlusion. Respiratory frequency and the relative duration of inspiration and expiration were unchanged. Paco2 decreased significantly during the infusion. The apnea attack rate, monitored by continuous recording, was significantly reduced after the first 6 hours of therapy. Six hours after starting doxapram, mean arterial blood pressure was significantly elevated, and continued to increase during the 24 hours of therapy. Doxapram is effective in treatment of apnea of prematurity refractory to aminophylline, and appears to act by increasing respiratory center output.  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