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   12597篇
  免费   688篇
  国内免费   61篇
耳鼻咽喉   180篇
儿科学   256篇
妇产科学   201篇
基础医学   1699篇
口腔科学   1476篇
临床医学   991篇
内科学   2470篇
皮肤病学   288篇
神经病学   886篇
特种医学   525篇
外科学   1133篇
综合类   100篇
一般理论   4篇
预防医学   1462篇
眼科学   210篇
药学   942篇
中国医学   138篇
肿瘤学   385篇
  2023年   116篇
  2022年   268篇
  2021年   435篇
  2020年   286篇
  2019年   404篇
  2018年   466篇
  2017年   321篇
  2016年   336篇
  2015年   407篇
  2014年   593篇
  2013年   716篇
  2012年   985篇
  2011年   1002篇
  2010年   603篇
  2009年   475篇
  2008年   661篇
  2007年   687篇
  2006年   556篇
  2005年   512篇
  2004年   441篇
  2003年   360篇
  2002年   326篇
  2001年   248篇
  2000年   218篇
  1999年   174篇
  1998年   149篇
  1997年   102篇
  1996年   102篇
  1995年   75篇
  1994年   69篇
  1993年   73篇
  1992年   65篇
  1991年   96篇
  1990年   85篇
  1989年   115篇
  1988年   102篇
  1987年   90篇
  1986年   57篇
  1985年   59篇
  1984年   48篇
  1983年   38篇
  1982年   37篇
  1981年   43篇
  1980年   38篇
  1979年   35篇
  1978年   31篇
  1977年   33篇
  1975年   30篇
  1974年   33篇
  1973年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
ObjectiveChildren admitted to the intensive care unit (ICU) are at risk of inadequate energy intake. Although studies have identified factors contributing to an inadequate energy supply in critically ill children, they did not take into consideration the length of time during which patients received their estimated energy requirements after having achieved a satisfactory energy intake. This study aimed to identify factors associated with the non-attainment of estimated energy requirements and consider the time this energy intake is maintained.MethodsThis was a prospective study involving 207 children hospitalized in the ICU who were receiving enteral and/or parenteral nutrition. The outcome variable studied was whether 90% of the estimated basal metabolic rate was maintained for at least half of the ICU stay (satisfactory energy intake). The exposure variables for outcome were gender, age, diagnosis, use of vasopressors, malnutrition, route of nutritional support, and Pediatric Index of Mortality and Pediatric Logistic Organ Dysfunction scores.ResultsSatisfactory energy intake was attained by 20.8% of the patients, within a mean time of 5.07 ± 2.48 d. In a multivariable analysis, a diagnosis of heart disease (odds ratio 3.62, 95% confidence interval 1.03–12.68, P = 0.045) increased the risk of insufficient energy intake, whereas malnutrition (odds ratio 0.43, 95% confidence interval 0.20–0.92, P = 0.030) and the use of parenteral nutrition (odds ratio 0.34, 95% confidence interval 0.15–0.77, P = 0.001) were protective factors against this outcome.ConclusionA satisfactory energy intake was reached by a small proportion of patients during their ICU stay. Heart disease was an independent risk factor for the non-attainment of satisfactory energy intake, whereas malnutrition and the use of parenteral nutrition were protective factors against this outcome.  相似文献   
92.
93.
In Brazil, as in many other countries, teenage pregnancy is widely recognised as a public health problem. Buttressed by a public health science of the economics of teenage pregnancy that emphasises the postponement of parenthood as key to poverty reduction, young people's lack of appreciation for medical knowledge of contraceptives is most often credited for failed attempts to reduce teenage pregnancy. Based on a longitudinal ethnographic study conducted in Pelotas, Brazil, with young people over the course of 10 years, our study found that young women who became teenage parents did not lack medical knowledge but were, rather, highly medicalised. Not only were they intensely concerned with the ill-effects of oral contraceptives on possible future fertility, they also engaged in intricate routines of contraceptive-use as a way of testing and safeguarding their fecundity. Our analysis attends to the way these practices are shaped by the problematisation of the economics of teenage pregnancy, as well as by the gendering of cultural norms relating to the transition to adulthood. We theorise the results by considering how contraceptive medicalisation enabled some women to engage with the authority of normative society, while developing a potent off-stage critique of this authority and of what they considered to be discriminatory messages imbedded in scientific discourses on teenage pregnancy.  相似文献   
94.
In this questionnaire study, the authors compared the prevalence of certain symptoms and signs associated with Sick Building Syndrome and perceptions relative to environmental discomfort of employees in a central-air-conditioned shopping center and in natural-ventilation commercial shops located on the streets of Niteröi, Rio de Janeiro, Brazil. There was a statistically significant higher prevalence of symptoms (e.g., water and itching of eyes, sore throat, nose irritation, difficulty breathing, skin irritation, sneezing) that were characteristic of Sick Building Syndrome in the air-conditioned building than in the naturally ventilated stores. The results indicated that there exists a continuing need for further research in Brazilian work environments.  相似文献   
95.
Phoma sabdariffae is the main roselle pathogenic fungus agent in Gabon. The present study was undertaken in order to experiment a biological strategy to eradicate this pathology. Hence, spice and ginger essential oils were extracted (rotavapor) and incorporated in PDA medium, constituting 3 concentrated (1/4, 1/2 and 3/4) samples. Fungus growth was measured after culture with a gradual ruler. The results showed all spice and ginger extracts inhibited significantly Phoma sabdariffae mycelium growth. Fungus inhibition rates were proportional to plant extracts’ concentrations. But for a same concentration the effects between the 2 plants’ essential oils weren’t different. Hence, the use of spice- and ginger-concentrated crude extracts may be envisaged against Phoma sabdariffae pathogenic agent.  相似文献   
96.
97.
ObjectiveThe objective of the study is to evaluate the effectiveness of nursing interventions (NIC) using nursing outcomes (NOC) and based on NANDA-I nursing diagnoses in patients with heart failure in home care.MethodIn this longitudinal study, 23 patients with heart failure were followed for 6 months, in four home visits. During the visits, nursing diagnoses were established, outcomes assessed, and interventions implemented.ResultsOf the 11 NIC interventions implemented, eight proved effective, that is, showed significant improvement between the first and the fourth visit, according to scores obtained for six outcomes: knowledge: treatment regimen, knowledge: medication, compliance behavior, symptom control, activity tolerance, and energy conservation.ConclusionNIC interventions health education, self-modification assistance, behavior modification, teaching: prescribed medication, teaching: disease process, nutritional counseling, telephone consultation, and energy conservation showed effective outcomes based on NOC scores, suggesting that the NANDA-I, NIC, and NOC linkage is useful in patients with heart failure in home care.  相似文献   
98.
99.
Leptospira interrogans serogroup Icterohaemorrhagiae is the major serogroup infecting humans worldwide, and rodents and dogs are the most significant transmission sources in urban environments. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the epidemiology of leptospirosis. In this study, 20 Leptospira isolates were evaluated by pulsed-field gel electrophoresis (PFGE), variable number tandem-repeat analysis (VNTR), serotyping, and determination of antimicrobial resistance profile. Isolates, originated from bovine, canine, human, and rodent sources, were characterized by microscopic agglutination test with polyclonal and monoclonal antibodies and were identified as L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni. MICs of antimicrobials often used in veterinary medicine were determined by broth microdilution test. Most of tested antibiotics were effective against isolates, including penicillin, ampicillin, and ceftiofur. Higher MIC variability was observed for fluoroquinolones and neomycin; all isolates were resistant to trimethoprim/sulfamethoxazole and sulphadimethoxine. Isolates were genotyped by PFGE and VNTR; both techniques were unable to discriminate between serovars Copenhageni and Icterohaemorrhagiae, as expected. PFGE clustered all isolates in 1 pulsotype, indicating that these serovars can be transmitted between species and that bovine, rodent, and dogs can maintain them in the environment endangering the human population.  相似文献   
100.
Background: Optimal methods of preparing students for high-stakes standardized patient (SP) examinations are unknown. Purposes: The purpose is to compare the impact of two formats of a formative SP examination (Web-based vs. in-person) on scores on a subsequent high-stakes SP examination and to compare students' satisfaction with each formative examination format. Methods: Clustered randomized trial comparing a Web-based module versus in-person formative SP examination. We compared scores on a subsequent high-stakes SP examination and satisfaction. Results: Scores on the subsequent high-stakes SP examination did not differ between the two formative formats but were higher after the formative assessment than without (p < .001). Satisfaction was higher with the in-person than Web-based formative assessment format (4.00 vs. 3.62 on a 5-point scale, p = .01). Conclusions: Two formats of a formative SP examination led to equivalent improvement in scores on a subsequent high-stakes examination. Students preferred an in-person formative examination to online but were satisfied with both.  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