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   7597篇
  免费   546篇
  国内免费   59篇
耳鼻咽喉   25篇
儿科学   286篇
妇产科学   175篇
基础医学   737篇
口腔科学   33篇
临床医学   1712篇
内科学   678篇
皮肤病学   74篇
神经病学   915篇
特种医学   31篇
外国民族医学   1篇
外科学   283篇
综合类   877篇
一般理论   4篇
预防医学   1779篇
眼科学   11篇
药学   332篇
  1篇
中国医学   42篇
肿瘤学   206篇
  2024年   26篇
  2023年   219篇
  2022年   350篇
  2021年   432篇
  2020年   419篇
  2019年   424篇
  2018年   363篇
  2017年   294篇
  2016年   281篇
  2015年   260篇
  2014年   576篇
  2013年   700篇
  2012年   422篇
  2011年   431篇
  2010年   335篇
  2009年   340篇
  2008年   369篇
  2007年   352篇
  2006年   281篇
  2005年   162篇
  2004年   148篇
  2003年   141篇
  2002年   98篇
  2001年   93篇
  2000年   88篇
  1999年   62篇
  1998年   61篇
  1997年   45篇
  1996年   44篇
  1995年   40篇
  1994年   41篇
  1993年   35篇
  1992年   19篇
  1991年   17篇
  1990年   21篇
  1989年   6篇
  1988年   18篇
  1987年   12篇
  1986年   16篇
  1985年   30篇
  1984年   25篇
  1983年   15篇
  1982年   11篇
  1981年   13篇
  1980年   16篇
  1979年   15篇
  1978年   9篇
  1977年   9篇
  1976年   9篇
  1975年   5篇
排序方式: 共有8202条查询结果,搜索用时 15 毫秒
991.
报告28个家庭HBV感染164人的血清学动态观察及10年随访。10年中曾有82人患过急性肝炎,9例死于原发性肝癌,8例死于肝硬化,7例死于重型肝炎,14例慢活肝,8例慢迁肝。结果表明,HBV感染家庭集聚者肝癌、肝硬化、重型肝炎的发生率和病死率极高。本文提示了在乙肝的防治工作中切实加强阻断母婴之间传播的同时,应积极开展对HBV感染家庭集聚人群的随访研究.  相似文献   
992.
One hundred and three phobic women not suitable for insight-oriented psychotherapy were randomized to either therapist-directed prolonged exposure in vivo (PE), supportive therapy of dynamic type (ST), relaxation therapy (R), or basal therapy (B). History taking was lengthy and included ratings of early interpersonal relations. These were combined into a scale with a range from 0, least favourable, to 13 most favourable. The patients filled in an inventory with regard to their experience of the therapist and the therapy at the beginning of the treatment, at midtreatment, and at the end of treatment, 3 months later. This inventory, the ETI, comprises different scales with ranges from least to most favourable experiences. The associations between the scales on the experience of early interpersonal relations and the ETI scales were studied. Most correlations were positive, indicating a similarity between the experience of early personal relations and the experience of the therapist and the therapy. The associations were significant at the start of therapy with B, and at the termination of therapy with R. These results are taken to indicate that when the desire for a personal relation with the therapist is frustrated the nature of the relation is interpreted according to the nature of the early relations. The fact that there was no association in ST indicates that when the patient is helped to express her reactions to current relations there is no need to fall back on early relations for the interpretation of the current ones. The opinion that it is possible to predict the character of the therapeutic relation from the character of early relations was supported.  相似文献   
993.
It is suggested, by means of a simple model, that the excess of medical students from social class I cannot be satisfactorily explained in terms of either social class differences in intellectual ability, or the excess of medical students from medical families.  相似文献   
994.
995.
BACKGROUND: Multiple risk factors possibly associated with lung cancer were examined as part of a large-scale residential radon case-control study conducted in Iowa between 1994 and 1997. We were particularly interested in stratifying risk factors by smoking status. Relatively little risk factor information is available for Midwestern rural women. METHODS: Four hundred thirteen female lung cancer cases and 614 controls aged 40-84, who were residents of their current home for at least 20 years, were included. Risk factors examined included cigarette smoking, passive smoking, occupation, chemical exposure, previous lung disease, family history of cancer, and urban residence. Multiple logistic regression analysis was conducted after adjusting for age, education, and cumulative radon exposure. RESULTS: As expected, active cigarette smoking was the major risk factor for lung cancer. While cessation of smoking was significantly associated with a reduced risk for lung cancer, the risk remained significantly elevated for 25 years. Among all cases, asbestos exposure was a significant risk. Among ex-smokers, pack-year history predominated as the major risk. Among never smokers, a family history of kidney or bladder cancer were significant risk factors (OR=7.34, 95% CI=1.91-28.18; and OR=5.02, 95% CI=1.64-15.39, respectively), as was a history of previous lung disease (OR=2.28, 95% CI=1.24-4.18) and asbestos exposure. No statistically significant increase in lung cancer risk was found for occupation or urban residence. CONCLUSIONS: Smoking prevention activities are urgently needed in rural areas of the United States. Relatives of individuals with smoking-related cancers are potentially at increased risk. Genetic risk factors should be more fully investigated in never smokers.  相似文献   
996.
Wen D  Wang S  Zhang L  Zhang J  Wei L  Zhao X 《Familial cancer》2006,5(4):343-352
Background Gene expression analyses indicate that there are 152 genes of which the expression differs significantly in esophageal squamous cell carcinoma (ESCC) cases with positive as opposed to those with negative family history of upper gastrointestinal cancer (FHUGIC) in the high-incidence area for ESCC in northern China. However, the question as to whether there is any difference of onset age or survival rates in the familial and sporadic cases of ESCC in the area is unknown.Aims To investigate the differences of onset age or survival rates in the familial and sporadic cases of ESCC for surgically treated ESCC patients from the high-incidence area.Methods Retrospective analyses were performed on the clinicopathologic and survival data of ESCC cases (N = 1715) who had undergone surgery alone from 1985 to 1994 in Hebei Cancer Center, a provincial cancer center established primarily to treat esophageal cancer in the high-incidence area, to investigate the differences. All the patients had been native residents of the high-incidence area in northern China. Student’s t-test was used to test the difference of onset ages, and Cox Proportional Hazard Model was used to examine the differences of survival rates in the familial and sporadic cases of ESCC.Results Although the familial cases of ESCC had had a significantly earlier onset than the sporadic cases (P < 0.00), they experienced relatively lower survival rates than the sporadic cases after surgery. The differences of survival rates in the familial and sporadic cases were significant for patients above the age of 50 years (P Wald = 0.04) and for the Tis, 1 N0M0 group (P Wald = 0.04), the differences were bigger for early-staged than for the later-stage groups, and the differences persisted when adjusted for or stratified by confounding factors such as sex, age (under versus above the age of 50 years), smoking, drinking, cancer segment location, surgery year (calendar year), stage (UICC 4th Ed, 1987), and Resection category. Overall, cases under the age of 50 years old showed a higher survival curve than cases above the age of 50 years old, and this was especially true for the familial case group where the difference was significant (P Wald = 0.03). Conclusion The findings suggest that the familial ESCC may develop earlier, and may have a poorer prognosis than the sporadic ESCC. Both earlier onset and poorer outcome may be important features for the familial as opposed to the sporadic cases of ESCC. The association between younger onset age and higher survival rates found for the familial cases may indicate some survival benefit for early discovery for people with positive FHUGIC in the high-incidence area.This work was partially supported by Grants from Hebei Provincial Natural Scientific Foundation (No. C2005000797), from Hebei Scientific Research (032761100D-1), and from the Key Project of Hebei Province (No.03276198D)  相似文献   
997.
OBJECTIVE: On the basis of a case study in Pakistan, the paper argues that good governance, characterized by transparency, accountability and meaningful community participation, plays a critical role in the sustainability of donor-funded health systems projects in the public health sector. METHODS: The Family Health Project (FHP) (1992-1999), funded by the World Bank, has been used as a case study. Critical analysis of secondary data mainly obtained from the Department of Health (DoH) in the province of Sindh in Pakistan is the major tool used for the study. Data from other sources including the World Bank have also been used. RESULTS: The analysis reveals that the existing health care system could not fully absorb and sustain major "sociopolitical" thrusts of the project, meaningful community participation and "democratic" decision-making processes being the most important ones. The hierarchical structure and management process made it difficult to produce a sense of ownership of the project among all managers and the rank and file staff. The Provincial Health Development Center (PHDC) and District Health Development Centers (DHDCs) established by the FHP did not receive adequate financial and political support from DoH and the Ministry of Health to have much control of the project at the local level. Consequently, these Centers largely failed to institutionalize a continuing training program for district level health officials/professionals. Due to lack of political support, the District Health Management Teams (DHMTs) could not be institutionalized. Community participation in the DHMTs was symbolic rather than forceful. Improved coordination among all stakeholders, more stable and competent leadership, more meaningful community participation, greater devolution of project management to the district level, and better management of resources would have resulted in more effective and efficient implementation of the project. Based on these findings, the paper introduces a Sustainable Management Approach (SMA) as a tool that can be used to ensure the sustainability of health systems projects, particularly those funded by international organizations in developing countries. CONCLUSIONS: Good governance and a conducive organizational culture are important prerequisites for incorporating any new project within an existing system. This includes prior consensus building among all stakeholders, a meaningful and inclusive participatory planning, implementation and evaluation process involving communities, political commitment, and the identification and use of appropriate leadership for project management.  相似文献   
998.
999.
1000.
BACKGROUND: The importance of routine data generated by GPs has grown extensively in the last decade. These data have found many applications other than patient care. More attention has therefore been given to the issue of data quality. Several systematic reviews have detected ample space for improvement of data quality. A new review was conducted in order to find out which methods of improvement are effective. METHOD: The Medline database was searched using an iteratively composed set of terms and MeSH (Medical Subject Headings) headings. Only papers that focused on explicit attempts at improving data quality of medical records in general practice were included. RESULTS: Twelve studies met the inclusion criteria. No study used patient-based comparison of records with external sources as the method to assess data quality improvement. Ten studies used internal indicators or markers of data quality instead. Attempts at data quality improvement often involve some sort of individualized feedback, and nearly all attempts seem to have some positive effect. Only one of the included studies fulfilled the basic methodological requirements of an intervention study. The most recent studies used a simple before-after design. CONCLUSION: No intervention to improve data quality has been put to a rigorous enough test. We still lack empirical knowledge as to how improvement can be brought about.  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