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   5613篇
  免费   413篇
  国内免费   36篇
耳鼻咽喉   85篇
儿科学   176篇
妇产科学   78篇
基础医学   842篇
口腔科学   204篇
临床医学   534篇
内科学   1166篇
皮肤病学   64篇
神经病学   553篇
特种医学   219篇
外科学   721篇
综合类   110篇
一般理论   4篇
预防医学   425篇
眼科学   207篇
药学   360篇
  1篇
中国医学   22篇
肿瘤学   291篇
  2023年   33篇
  2022年   69篇
  2021年   155篇
  2020年   97篇
  2019年   150篇
  2018年   153篇
  2017年   123篇
  2016年   171篇
  2015年   154篇
  2014年   182篇
  2013年   287篇
  2012年   418篇
  2011年   415篇
  2010年   229篇
  2009年   224篇
  2008年   349篇
  2007年   351篇
  2006年   317篇
  2005年   329篇
  2004年   300篇
  2003年   246篇
  2002年   256篇
  2001年   65篇
  2000年   60篇
  1999年   61篇
  1998年   74篇
  1997年   41篇
  1996年   45篇
  1995年   33篇
  1994年   36篇
  1993年   36篇
  1992年   30篇
  1991年   31篇
  1990年   20篇
  1989年   16篇
  1988年   31篇
  1987年   19篇
  1986年   34篇
  1985年   31篇
  1984年   24篇
  1983年   20篇
  1982年   21篇
  1981年   32篇
  1980年   25篇
  1979年   36篇
  1978年   23篇
  1977年   21篇
  1976年   16篇
  1974年   16篇
  1973年   21篇
排序方式: 共有6062条查询结果,搜索用时 46 毫秒
1.
Problem: Although efficacy studies of opioid maintenance treatment (OMT) have shown evidence of treatment benefits, there is still need for studies on its effectiveness in natural clinical processes. This study investigates the development in health, substance use and social conditions of those who applied for OMT, including those denied access or discharged.

Method: First, persons assessed for admittance in 2005–2011 (n?=?127) were categorized into four trajectory groups based on whether they were admitted or denied (n?=?19), discharged (n?=?31), readmitted (n?=?21) or had been undergoing OMT without interruption (n?=?56). Second, 99 of these, the analytical sample, were interviewed at follow-up using (a) the Addiction Severity Index (ASI) for seven problem-areas and housing, and (b) self-rated change in 11 problem areas. The ASI was compared to baseline interviews after 55 months (mean). Third, outcomes within groups was studied in relation to alternative interventions.

Results: Within the analytical sample, those denied OMT showed no improvements at group level, those discharged had some improvements, more if readmitted than if not and those with uninterrupted OMT showed the most comprehensive improvements. Those outside OMT, denied and discharged, had considerable mortality risks related to ongoing drug use, especially in lack of well-planned alternative interventions.

Conclusion: Improvements strongly relate to access to OMT. This study underscores that access to OMT improves the situation in all areas investigated and decreases the risk for drug-related death. It underscores the importance of two major risk situations, i.e. being denied OMT and being discharged.  相似文献   

2.
目的 了解医学生学习《健康教育》课程的满意度、需求度现状及差异,为《健康教育》课程优化提供参考。方法 以某医科大学在校临床医学生为研究对象,分析医学生对课程内容的需求度和满意度及二者差异。课程内容包括服药依从性、戒烟干预、合理膳食、心理压力管理、中医康复技术、慢性传染病健康教育、急性传染病健康教育、移动健康技术教育、运动康复指导及健康促进理论。采用频数和构成比指标进行统计描述,采用卡方检验进行健康教育课程学习情况与专业/ 学制之间、相关课程内容学习的需求度与学制的差异,相关课程内容学习需求度与满意度的关联比较采用秩和检验。以P < 0.05 为差异具有统计学意义。结果 戒烟干预、合理膳食、心理压力管理、中医康复技术、慢性传染病健康教育、急性传染病健康教育、移动健康技术教育及健康促进理论八项的学习需求度在长学制医学生与五年制医学生中的总体分布位置不同(U = 2.4、2.2、2.5、2.3、2.4、2.4、2.3、2.0,P 均< 0.05);服药依从性、戒烟干预、合理膳食、心理压力管理、慢性传染病健康教育、急性传染病健康教育、移动健康技术教育及运动康复指导八项的满意度与需求度之间的总体位置分布不同(U = 6.2、5.2、7.2、9.2、5.9、6.1、2.1、3.2,P 均< 0.05);不同学制的医学生对于慢性病人、老年人、孕产妇、传染病人、高危人群和职业暴露人群的健康教育重点关注人群侧重有所不同,其差异具有统计学意义(χ2 = 8.9、14.2、9.9、6.9、23.9、17.8,P 均< 0.05);在教学方式上,不同学制的医学生对于教师课堂讲授和小组讨论的偏好上的差异具有统计学意义(χ2=6.3、9.5,P 均< 0.05)。结论 当前健康教育课程的教学内容和结构未能完全满足不同学制、年级医学生的学习需求,需要对课程教学内容、教学方式和开设时间进行进一步的优化设计。  相似文献   
3.

Background and study aims

Acute upper gastrointestinal bleeding is one of the main causes of hospitalisation. The purpose of this study was to determine the prognostic factors in non-variceal upper gastrointestinal bleeding.

Patients and methods

Clinical outcomes, demographic and laboratory variables of the subjects were collected from the HIS software and national code with the SQL format from three hospitals in Qazvin. The data were linked to the database software designed by the author. Clinical and upper endoscopic findings of patients’ records were collected through a questionnaire form in the designed software database.

Results

In this study, 29.2% of patients with favourable outcome and 64.2% of patients with unfavourable clinical outcomes had a history of anticoagulant drug use before hospitalisation (p?<?0.001). The prevalence of chronic cardiovascular disease, chronic liver disease, chronic lung disease, diabetes and dialysis was higher in subjects with poor clinical outcomes than those with a favourable clinical outcome.53.1% of subjects with favourable clinical outcome and 90.5% of subjects with undesirable clinical outcomes received packed red blood cell transfusion (p?<?0.001). 16.1% of subjects with desirable clinical outcome and 86.3% of subjects with undesirable clinical outcomes received endoscopic haemostatic treatment which was statistically significant (p?<?0.001).

Conclusion

Undesirable clinical outcome in patients with acute non-variceal upper gastrointestinal bleeding has a significant statistical association with longer hospitalisation, chronic underlying disease, anticoagulant administration, packed red blood cell infusion, higher Forrest stage, low systolic blood pressure, higher age, low haemoglobin, low platelet count, high INR and high BUN at the onset of diagnosis.  相似文献   
4.
5.
Osteoporosis is a major public health problem in the Western countries and is projected to have a similar impact in the Middle East. It has been suggested that peak bone mineral density (BMD), a major determinant of osteoporotic fractures later in life, may be lower in this part of the world compared with the Western world. The purpose of the Iranian Multicenter Osteoporosis Study was to determine peak bone mass in a randomly chosen sample of healthy Iranian subjects. A total of 5201 participants (2340 males, mean age 42.7+/-13.8) were recruited based on randomized clustered sampling from all regions of five major cities across the country. In women, peak lumbar BMD (1.182+/-0.127 g/cm2) occurred in the 29- to 33-yr age group, whereas peak total femur BMD (1.006+/-0.126 g/cm2) occurred in the 32- to 36-yr age group. In men, peak lumbar BMD (1.181+/-0.153 g/cm2) and femoral BMD (1.096+/-0.159 g/cm2) both occurred in the 20- to 24-yr age group. When standardized to mg/cm2 units using established formulas, Iranian peak bone mass values are comparable with that of Western countries and are generally higher than that of Eastern Asian and Middle Eastern countries.  相似文献   
6.
BACKGROUND: The role of large colony streptococci groups C or G as pathogen agents in sore throat has been questioned. AIM: To analyse clinical features of patients with large colony streptococci groups C or G compared with patients with group A streptococci (GAS) and with negative cultures. DESIGN OF STUDY: Prospective study of patients with sore throat. SETTING: Two Norwegian general practices in Stokke and Kongsberg communities with 6500 patients.METHOD: Frequency of clinical features in the three patient categories including the four Centor criteria (fever, anterior cervical lymphadenopathy, tonsillar exudates, and lack of cough), degree of pain on swallowing, pharyngeal rubor, C-reactive protein (CRP) values, patient age between 3 and 14 years, and duration of symptoms before seeing the doctor. A logistic regression analysis to find independent predictors was performed. RESULTS: Out of 306 patients with a sore throat, 244 were adults and 62 were children under 10 years old; 40% were men. One hundred and twenty-seven had GAS, 33 had streptococci groups C or G, and 146 had negative throat cultures. Forty-eight per cent of the GAS patients and 45% of the C or G patients met three or four of the Centor criteria. The logistic regression revealed that in patients with GAS considerable pain on swallowing, an age of 3-14 years and a duration of symptoms of < or =3 days or less were significantly associated with GAS infection in addition to the Centor criteria. The same results were found when all streptococci were analysed together, in addition elevated CRP was significant. In patients with streptococci group C or G an elevated CRP-value was significantly associated. CONCLUSION: Patients with tonsillitis caused by streptococcus groups C or G have, to a large extent, the same clinical picture as patients with GAS. Large colony streptococci groups C and G should be considered as throat pathogens in line with GAS.  相似文献   
7.
Aim: To investigate the clinico‐pathological profile and stage of disease at presentation of patients with carcinoma of the gallbladder diagnosed during 1992–2006 in Iran. Methods: During this study period 34 consecutive patients with gallbladder carcinoma were identified using a pathology‐based tumor database. The data extracted for each study patient included their gender, age at diagnosis, signs and symptoms, presence of gallstones and histopathological pattern of the gallbladder carcinoma and the UICC/AJCC TNM staging system was used for labeling the stages of the disease. Results: The median age of the 34 patients studied was 69.50 with most between 61 and 70 years of age. The age range of the men was between 53 and 80 years with a median age of 71.50 years and that of the women was between 33 and 79 years with a median age of 68.50 years. The most common symptom was pain in the right hypochondrium. More women had gallstones (15/34) than men (3/10). Adenocarcinoma was the most common histopathological type (91.18%) with the commonest subtype being papillary (47.06%). Eighteen patients had stage IB and stage IIA (52.94%) carcinomas whereas stages IIB and III were observed in six (17.6%) and seven cases (20.6%), respectively. Only three cases (8.82%) were seen in stage IV. The follow up of gall bladder carcinoma (GBC) patients in this study ranged from 6 to 60 months. However, there was a progressive reduction of patients attending follow‐up oncology clinic, particularly by those who had stages III and IV of the disease. Conclusion: Most patients (52.94%) presented with early disease (stage IB and IIA) which carries a good prognosis. Early detection of GBC and a national consensus for the evidence‐based management of GBC in Iran should be the major components of a strategy aimed at improving therapeutic outcome.  相似文献   
8.
Elevation of plasma thioredoxin levels in HIV-infected individuals   总被引:3,自引:0,他引:3  
Thioredoxin (Trx), a ubiquitous protein intimately involvedin redox and protein disulfide reductions, has been shown tobe released from cells and to have cytokine-like activities.In addition, Trx has been implicated in the redox regulationof immunological responses and shown to be deficient in tissuesfrom AIDS patients. In studies presented here, plasma Trx levelswere measured by ELISA in plasma samples from HIV-infected individuals(n = 136) and HIV-negative controls (n = 47). To account forthe release of Trx into plasma due to hemolysis, the Trx measurementswere corrected according to the level of hemoglobin in the plasmasample. Data presented show that, in contrast to tissue Trxlevels, corrected plasma Trx levels are significantly higherin HIV-infected individuals than in controls (P < 0.0001).Furthermore, {small tilde}25% of the HIV-infected individualsstudied have plasma Trx levels greater than the highest levelfound in controls (37 ng/ml). Detailed multiparameter FACS analysisof peripheral blood mononuclear cells (PBMC) from the infectedindividuals demonstrates that those with higher plasma Trx levels(37 ng/ml or greater) tend to have lower overall CD4 counts.In addition, increases in plasma Trx levels correlate with decreasesin monochlorobimane staining (indicative of lower intracellularglutathione levels in PBMC) and with changes in surface antigenexpression (CD62L, CD38 and CD20) that occur in the later stagesof HIV infection. These correlations suggest that elevationof plasma Trx levels may be an important component of advancedHIV disease, perhaps related to the oxidative stress that oftenoccurs at this stage.  相似文献   
9.
10.
Virus-induced alterations in the cellular expression of chemokines may be important in directing the migration of specific leucocyte subsets to sites of infection, thereby playing a pivotal role in viral pathogenesis. We show here that cytomegalovirus (CMV) infection of human fibroblasts resulted in significantly increased expression of the C-X-C or alpha-chemokine interleukin-8 (IL-8), at both the mRNA and protein levels. Increased IL-8 production was seen following infection with the high passage laboratory CMV strains AD169, Towne, or Davis, as well as the low passage clinical CMV isolates Toledo or C1F. The increase in IL-8 production had functional consequences, as demonstrated by the ability of supernatants from CMV-infected fibroblasts to significantly enhance neutrophil transendothelial migration. The latter was independent of alterations in adhesion molecule expression on the endothelial cells, and was abrogated by neutralizing antibodies specific for IL-8. Direct infection of endothelium with the endothelial cell-tropic CMV strain C1FE, also resulted in enhanced neutrophil transendothelial migration. Neutrophils play an important role in the dissemination of CMV throughout the body, and thus CMV-induced neutrophil recruitment would be expected to enhance CMV dissemination. Increased production of chemokines in response to CMV infection could also disrupt the fine balance between a beneficial and a destructive immune response, thereby potentially contributing to pathology.  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