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   19155篇
  免费   1622篇
  国内免费   41篇
耳鼻咽喉   267篇
儿科学   678篇
妇产科学   458篇
基础医学   2739篇
口腔科学   275篇
临床医学   2676篇
内科学   4231篇
皮肤病学   230篇
神经病学   1790篇
特种医学   434篇
外国民族医学   2篇
外科学   1743篇
综合类   195篇
一般理论   22篇
预防医学   2373篇
眼科学   237篇
药学   1211篇
中国医学   17篇
肿瘤学   1240篇
  2023年   199篇
  2022年   250篇
  2021年   463篇
  2020年   376篇
  2019年   547篇
  2018年   558篇
  2017年   490篇
  2016年   491篇
  2015年   542篇
  2014年   668篇
  2013年   999篇
  2012年   1310篇
  2011年   1288篇
  2010年   742篇
  2009年   654篇
  2008年   1104篇
  2007年   1103篇
  2006年   1047篇
  2005年   944篇
  2004年   885篇
  2003年   810篇
  2002年   755篇
  2001年   353篇
  2000年   252篇
  1999年   266篇
  1998年   180篇
  1997年   129篇
  1996年   136篇
  1995年   127篇
  1994年   127篇
  1993年   104篇
  1992年   200篇
  1991年   224篇
  1990年   203篇
  1989年   224篇
  1988年   169篇
  1987年   166篇
  1986年   171篇
  1985年   164篇
  1984年   123篇
  1983年   132篇
  1982年   100篇
  1981年   66篇
  1980年   71篇
  1979年   103篇
  1978年   81篇
  1977年   66篇
  1976年   59篇
  1974年   57篇
  1973年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Microalbuminuria as a predictor of preeclampsia.   总被引:1,自引:0,他引:1  
Urinary albumin concentration (UA) and albumin/creatinine ratio (UA/UC) in early morning specimens were assayed in 225 consecutive pregnant women at 20, 26, 28 and 30 weeks of gestation. 193 did not develop preeclampsia (control group), 14 developed preeclampsia later (preeclamptic group), 9 were excluded and 9 dropped out. Reference intervals of UA and UA/UC of healthy pregnant women (wk 20-30) was obtained. A statistically significant increase in urinary albumin excretion was observed with increasing gestational age as a normal phenomenon. There was no significant difference in the values of UA and UA/UC in the preeclamptic group when compared with the control group at the same stage of gestation. This indicates that microalbuminuria cannot be used as a predictor of preeclampsia.  相似文献   
42.
S S Pedersen  N Hiby  F Espersen    C Koch 《Thorax》1992,47(1):6-13
BACKGROUND: Chronic bronchopulmonary infection with mucoid, alginate producing Pseudomonas aeruginosa occurs characteristically in patients with cystic fibrosis. Alginate may be a virulence factor for P aeruginosa infection in such patients. METHODS: Forced vital capacity (FVC), nutritional state and the antibody response to P aeruginosa were determined at regular intervals from three years before chronic P aeruginosa infection to 10 years afterwards in 73 patients with cystic fibrosis. All patients were treated intensively with antipseudomonal chemotherapy during the study period. RESULTS: FVC was reduced in all patients who subsequently developed P aeruginosa infection before they acquired the infection, indicating significant pre-existing lung damage when compared with patients who remained free of P aeruginosa. Lung function and nutritional state remained unchanged after 10 years of infection, except in the patients who died of P aeruginosa lung infection. The FVC and height and weight of patients infected with nonmucoid strains of P aeruginosa were similar to those of uninfected patients. Patients infected with mucoid strains had poorer lung function and nutritional state for the first five years after infection compared with patients with nonmucoid strains. Such infection was also associated with greater IgG and IgA antibody responses to P aeruginosa standard antigen compared with nonmucoid infection. Concentrations of antibody to alginate were similar in patients with non-mucoid and mucoid infection. Noticeably increased concentrations of IgA antibodies to P aeruginosa standard antigen were observed early after the onset of infection in patients who subsequently died. CONCLUSION: Alginate producing P aeruginosa infection is associated with a hyperimmune response and poor clinical condition, suggesting that alginate production is a virulence factor in such infections in patients with cystic fibrosis.  相似文献   
43.
Identifying environmental factors reflected to alcohol use is important for program planning and evaluation in college alcohol and drug prevention programs. Little has been written concerning uses of data in environmental prevention efforts. This paper presents four brief interrelated case studies of how environmental modifications were used by a college alcohol prevention project to 1) change the marketing practices and service policies of a student-oriented bar, 2) alter the sales practices of a campus bookstore concerning alcohol paraphernalia, 3) to develop a campaign with the goal of reducing risk factors related to heavy drinking at private student parties, and 4) stop an unsafe bus from transporting students to bars in Mexico. Creative use of such environmental prevention approaches has potential benefit to colleges and universities concerned with the primary prevention of alcohol-related problems experienced by students.  相似文献   
44.
45.
Stroke rehabilitation is an area of practice that many occupational therapists encounter during their career. The literature promotes a wide range of management techniques and support devices for people who have a stroke-affected upper limb, but little is known about the validity of those that occupational therapists actually use in practice. A questionnaire was sent to occupational therapists working in Queensland and northern New South Wales facilities (n = 35), in which adults with a stroke were likely to be treated. Eighteen respondents answered questions about the management techniques and support devices used in their facility, and their perception of the benefit of these devices in the reduction of hemiplegic shoulder pain. Results are discussed with reference to evidence-based practice and indicate an urgent need for the collation and dissemination of the best current evidence available for the management techniques and support devices used in this area, as well as further research to extend this evidence.  相似文献   
46.
Patients with cystic fibrosis commonly acquire chronic pulmonary infection with alginate-producing Pseudomonas aeruginosa. The infection remains localized at the mucosal surfaces of the airways. Using enzyme-linked immunosorbent assays immunoglobulin concentrations and titers of specific antibodies to purified P. aeruginosa alginate and to P. aeruginosa sonicated antigens were measured in tears, saliva, sputum and serum. CF patients had significantly higher concentrations of IgG, IgA and SIgA in serum and saliva than controls. They also had significantly higher levels of specific antibodies to alginate and sonicated antigen in secretions and serum. Local production of IgA, IgG and IgM antibodies to P. aeruginosa was demonstrated. Only a minor proportion of specific IgA antibodies were present as secretory IgA in tears, saliva and sputum. The ratio of alginate-specific SIgA to specific monomeric IgA in sputum was significantly lower than the similar ratio in saliva, whereas the same ratio for specific P. aeruginosa sonicate antigens was found in saliva and sputum.  相似文献   
47.
48.

Objective

To estimate the national prevalence of arthritis‐attributable work limitation (AAWL) among persons ages 18–64 with doctor‐diagnosed arthritis and examine correlates of AAWL.

Methods

Using the 2002 National Health Interview Survey, we estimated the prevalence of AAWL (limited in whether individuals work, the type of work they do, or the amount of work they do) and correlates of AAWL in univariable and multivariable‐adjusted logistic regression analyses. Survey data were analyzed in SAS and SUDAAN to account for the complex sample design.

Results

A total of 5.3% of all US adults ages 18–64 reported AAWL; in this age group, AAWL is reported by ~30% of those who report arthritis. The prevalence of AAWL was highest among people ages 45–64 years (10.2%), women (6.3%), non‐Hispanic blacks (7.7%), people with less than a high school education (8.6%), and those with an annual household income <$20,000 (12.6%). AAWL was substantially increased among people with arthritis‐attributable activity limitations (multivariable‐adjusted odds ratio [OR] 9.1, 95% confidence interval [95% CI] 7.1–11.6). The multivariable‐adjusted likelihood of AAWL was moderately higher among non‐Hispanic blacks (OR 1.6, 95% CI 1.2–2.3), Hispanics (OR 1.8, 95% CI 1.2–2.6), and people with high levels of functional/social/leisure limitations (OR 1.8, 95% CI 1.4–2.3) and was decreased among those with a college education (OR 0.6, 95% CI 0.4–0.8).

Conclusion

AAWL is highly prevalent, affecting millions of Americans and one‐third of adults with doctor‐diagnosed arthritis. Findings suggest the need for more targeted research to better understand the natural history, success of interventions, and effects of policy on AAWL. Public health interventions, including self‐management education programs, may be effective in countering AAWL.  相似文献   
49.
The use of mechanical ventilation in the Emergency Department requires adequate resources in order to maintain patient safety and avoid potential risks. Moreover, developments in technology require increased knowledge of mechanical ventilation techniques to address the complexity of decision-making involved. Organisational issues and system factors have the potential to negatively impact on the ability of the emergency service to provide optimum care to patients receiving mechanical ventilation. These issues include staffing and skill-mix, demand on emergency services, role-delineation, scope of practice, and current mechanisms for monitoring of quality and safety. Furthermore, in response to advances in ventilator technology, current education programs for both nursing and medical staff require review to ensure that they provide comprehensive information about the types of ventilation techniques now available and the relative risks and benefits associated with their application.This article is the second in a two-part series and explores the educational and organisational factors that impact upon safety and quality of care delivered to patients receiving mechanical ventilation in the emergency department. Recommendations for future policy development, curriculum review and reporting mechanisms to support further research in the application of mechanical ventilation in the emergency department are made.  相似文献   
50.
Patients with lung cancer experience considerable distress. Therefore, accurate methods for assessing distress and quality of life over time may play a key role for managing and evaluating palliative care. Alternatives to commonly used standardized questionnaires are individual measures. This study prospectively and retrospectively explored the concerns that 46 patients with inoperable lung cancer spontaneously reported as causing most distress close to diagnosis and 6 months later. Changes in content individually generated through a structured inductive freelisting were compared with EORTC-QLQ-C30+LC13 ratings. The results showed that patients perceived a wide variety of concerns as most distressing and that their concerns changed over time. Between 56 and 62% of these concerns were assessed by items included in the EORTC-QLQ-C30+LC13 questionnaires. Furthermore, patients’ reports of most distress from fatigue, pain and dyspnea were not always reflected in intensity ratings of comparable EORTC-QLQ-C30+LC13 items. These results indicate that items included in standardized measures are not always adequate to assess patients’ concerns, priorities and changes over time. In addition to standardized questionnaires, individualized measures may be useful in the clinical palliative setting for providing detailed information about the individual’s problems and prioritizations.  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