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   6352篇
  免费   443篇
  国内免费   26篇
耳鼻咽喉   48篇
儿科学   247篇
妇产科学   137篇
基础医学   997篇
口腔科学   64篇
临床医学   718篇
内科学   1245篇
皮肤病学   64篇
神经病学   854篇
特种医学   153篇
外科学   607篇
综合类   39篇
预防医学   650篇
眼科学   56篇
药学   495篇
中国医学   26篇
肿瘤学   421篇
  2024年   9篇
  2023年   45篇
  2022年   73篇
  2021年   177篇
  2020年   107篇
  2019年   161篇
  2018年   184篇
  2017年   139篇
  2016年   154篇
  2015年   194篇
  2014年   218篇
  2013年   316篇
  2012年   442篇
  2011年   516篇
  2010年   273篇
  2009年   248篇
  2008年   416篇
  2007年   434篇
  2006年   415篇
  2005年   408篇
  2004年   401篇
  2003年   362篇
  2002年   341篇
  2001年   54篇
  2000年   52篇
  1999年   60篇
  1998年   67篇
  1997年   63篇
  1996年   65篇
  1995年   44篇
  1994年   38篇
  1993年   35篇
  1992年   26篇
  1991年   22篇
  1990年   26篇
  1989年   19篇
  1988年   18篇
  1987年   22篇
  1986年   12篇
  1985年   13篇
  1984年   23篇
  1983年   13篇
  1982年   17篇
  1981年   14篇
  1980年   21篇
  1979年   12篇
  1978年   12篇
  1977年   5篇
  1973年   5篇
  1969年   7篇
排序方式: 共有6821条查询结果,搜索用时 15 毫秒
121.
Community-based conservation (CBC) promotes the idea that conservation success requires engaging with, and providing benefits for, local communities. However, CBC projects are neither consistently successful nor free of controversy. Innovative recent studies evaluating the factors associated with success and failure typically examine only a single resource domain, have limited geographic scope, consider only one outcome, or ignore the nested nature of socioecological systems. To remedy these issues, we use a global comparative database of CBC projects identified by systematic review to evaluate success in four outcome domains (attitudes, behaviors, ecological, economic) and explore synergies and trade-offs among these outcomes. We test hypotheses about how features of the national context, project design, and local community characteristics affect these measures of success. Using bivariate analyses and multivariate proportional odds logistic regressions within a multilevel analysis and model-fitting framework, we show that project design, particularly capacity-building in local communities, is associated with success across all outcomes. In addition, some characteristics of the local community in which projects are conducted, such as tenure regimes and supportive cultural beliefs and institutions, are important for project success. Surprisingly, there is little evidence that national context systematically influences project outcomes. We also find evidence of synergies between pairs of outcomes, particularly between ecological and economic success. We suggest that well-designed and implemented projects can overcome many of the obstacles imposed by local and national conditions to succeed in multiple domains.  相似文献   
122.
123.
124.
The monetary incentive delay (MID) task (Knutson, 2000) is an imaging paradigm used to measure neural activity of incentive receipt anticipation. The task reliably elicits striatal activation and is commonly used with both adult and adolescent populations, but is not designed for use with children. In the current article, we present data on the newly designed ‘piñata task’ a child-friendly analog of the MID task. We demonstrate the task can be used successfully in children to study the neural correlates of anticipatory incentive processing. Results from a behavioral study and a neuroimaging study are reported. In Study #1, a sample of 8- to 14-year-old children demonstrates expected behavioral effects: subjects responded most quickly and most accurately on trials with greater potential rewards; older children displayed faster reaction times than younger. In Study #2, 8- to 12-year-old children showed neural activation patterns consistent with those seen in adults in the MID task: activation was modulated by cue incentive value in reward-processing regions, including the striatum, thalamus, mesial prefrontal cortex and insula. Study results suggest that the piñata task is a valid analog of the MID task, and can be used to assess neural correlates of reward processing in children as young as 8–9 years of age.  相似文献   
125.
IgG avidity tests are used to discriminate acute from chronic infections. There are few reports on the IgG avidity profile of patients with visceral leishmaniasis (VL). This study investigated the anti-Leishmania IgG avidity in patients with classic VL (n = 10), patients showing clinical cure after treatment (n = 18), and asymptomatic subjects with at least one positive Leishmania test (n = 20). All subjects were from areas in Brazil where VL is endemic. Serum samples were collected from each subject on two different occasions. IgG avidity was evaluated by Western blotting. The proportion of high-avidity antibodies was higher in all samples from patients with classic VL. In contrast, low-avidity antibodies predominated in subjects with a history of VL, including 13 cases (72.2%) in the first assessment and 14 (77.8%) in the second. Fifteen (75%) of the asymptomatic subjects presented a predominance of low-avidity antibodies in the first assessment, and the frequency of high-avidity antibodies increased over time in seven subjects (35%) of this group. Antibodies against the 14- and/or 16-kDa antigen fraction were detected in the first assessment in all patients with classic VL, in 10 (55.5%) treated patients, and in 10 (50%) asymptomatic subjects. These were high-avidity antibodies in most cases. In the asymptomatic group, an increase in IgG avidity against the 14- and/or 16-kDa antigen fraction was observed in three cases (15%). The results indicate distinct responses in infected and asymptomatic subjects, probably associated with the length of time after infection. In this respect, IgG avidity tests represent a new approach to better characterize asymptomatic VL.  相似文献   
126.
This person-centered study examines the extent to which parents’ language dominance influences the effects of an after school, multi-family group intervention, FAST, on low-income children’s emotional and behavioral outcomes via parents’ relations with other parents and with school staff. Social capital resides in relationships of trust and shared expectations, which are highly dependent on whether parents share the language of other parents and teachers. This study is based on a community epidemiologically-defined sample of Latino families (N = 3,091) in San Antonio, Texas and Phoenix, Arizona. Latent profile analyses revealed three language profiles of parents across the two cities: English-dominant, Spanish-dominant, and bilingual. Path models revealed that FAST did not have a direct or indirect effect on children’s emotional and behavior functioning, although FAST increased parent–parent and parent-school social capital among Spanish-dominant parents in Arizona and these parent–parent relations were associated with better child outcomes. Implications for interventions are discussed.  相似文献   
127.
128.
The early detection of asymptomatic prostate cancer has led to the increased incidence of tumours that are unlikely to become symptomatic during life, so called indolent cancers. The prediction of low risk and indolent prostate cancer is needed to avoid overtreatment by unnecessary invasive therapies, and select men for active surveillance. Some of the currently available nomograms predicting these low risk tumours have been validated in independent populations. However, assessment to the compliance with their treatment advises based on the calculation of probability are scarce. The ultimate value of nomograms for the urologic practice can only be assessed by analysing their practical implementation.  相似文献   
129.
130.
Background & study aimsAdjuvant endocrine therapy effectively prevents recurrence and progression of estrogen-receptor positive breast cancer. However, studies reveal substantial non-adherence. The objective was therefore to identify the nature of the experiences and beliefs of women treated with endocrine therapy in an attempt to find potential determinants of non-adherence.MethodOnline Focus Groups (OFGs) and individual interviews were conducted with 37 women who were treated with endocrine therapy. Sixty-three statements derived from the OFGs and 11 belief items from the Beliefs about Medicines Questionnaire (BMQ) were used in a Q-sorting task conducted with 14 of the women. The quantitative Q-sorting data were statistically analyzed with Hierarchical Cluster Analysis.ResultsA six cluster solution was revealed that included the clusters ‘information’, ‘efficacy’, ‘tenacity’, ‘coping’, ‘side effects’ and ‘usage’. Women's own experiences and perceptions were not clearly delineated from the beliefs measured with the BMQ. However, women judged their own experiences and perceptions with regard to endocrine therapy as more relevant for adherence than the BMQ beliefs.ConclusionIn order to understand and to improve women's adherence to endocrine therapy, women's own perceptions and experiences about endocrine therapy should be targeted in addition to common beliefs that apply to a wide range of medicines.  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