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   18709篇
  免费   1517篇
  国内免费   50篇
耳鼻咽喉   135篇
儿科学   647篇
妇产科学   476篇
基础医学   2979篇
口腔科学   251篇
临床医学   2247篇
内科学   3426篇
皮肤病学   382篇
神经病学   2169篇
特种医学   402篇
外科学   2069篇
综合类   99篇
一般理论   24篇
预防医学   2017篇
眼科学   321篇
药学   1167篇
中国医学   34篇
肿瘤学   1431篇
  2024年   64篇
  2023年   211篇
  2022年   422篇
  2021年   810篇
  2020年   509篇
  2019年   706篇
  2018年   718篇
  2017年   578篇
  2016年   635篇
  2015年   664篇
  2014年   845篇
  2013年   1161篇
  2012年   1635篇
  2011年   1615篇
  2010年   755篇
  2009年   717篇
  2008年   1229篇
  2007年   1177篇
  2006年   1059篇
  2005年   1035篇
  2004年   956篇
  2003年   839篇
  2002年   715篇
  2001年   124篇
  2000年   70篇
  1999年   106篇
  1998年   132篇
  1997年   108篇
  1996年   74篇
  1995年   63篇
  1994年   63篇
  1993年   49篇
  1992年   45篇
  1991年   39篇
  1990年   31篇
  1989年   25篇
  1988年   22篇
  1987年   32篇
  1986年   20篇
  1985年   21篇
  1984年   21篇
  1983年   22篇
  1982年   24篇
  1981年   20篇
  1980年   18篇
  1979年   9篇
  1977年   11篇
  1974年   8篇
  1973年   7篇
  1972年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
The ballistocardiographic (BCG) artifact is linked to cardiac activity and occurs in electroencephalographic (EEG) recordings acquired inside the magnetic resonance (MR) environment. Its variability in terms of amplitude, waveform shape and spatial distribution over subject’s scalp makes its attenuation a challenging task. In this study, we aimed to provide a detailed characterization of the BCG properties, including its temporal dependency on cardiac events and its spatio-temporal dynamics. To this end, we used high-density EEG data acquired during simultaneous functional MR imaging in six healthy volunteers. First, we investigated the relationship between cardiac activity and BCG occurrences in the EEG recordings. We observed large variability in the delay between ECG and subsequent BCG events (ECG–BCG delay) across subjects and non-negligible epoch-by-epoch variations at the single subject level. The inspection of spatial–temporal variations revealed a prominent non-stationarity of the BCG signal. We identified five main BCG waves, which were common across subjects. Principal component analysis revealed two spatially distinct patterns to explain most of the variance (85% in total). These components are possibly related to head rotation and pulse-driven scalp expansion, respectively. Our results may inspire the development of novel, more effective methods for the removal of the BCG, capable of isolating and attenuating artifact occurrences while preserving true neuronal activity.  相似文献   
53.
Parasitology Research - Nematodes of the genus Physaloptera are common in rodents, including in species of the Family Cricetidae. There is no report of nematodes parasitizing Cerradomys goytaca, so...  相似文献   
54.

Background

Despite recent developments aimed at creating international guidelines for ethical global health research, critical disconnections remain between how global health research is conducted in the field and the institutional ethics frameworks intended to guide research practice.

Discussion

In this paper we attempt to map out the ethical tensions likely to arise in global health fieldwork as researchers negotiate the challenges of balancing ethics committees’ rules and bureaucracies with actual fieldwork processes in local contexts. Drawing from our research experiences with an implementation and evaluation project in Jamaica, we argue that ethical research is produced through negotiated spaces and reflexivity practices that are centred on relationships between researchers and study participants and which critically examine issues of positionality and power that emerge at multiple levels. In doing so, we position ethical research practice in global health as a dialectical movement between the spoken and unspoken, or, more generally, between operationalized rules and the embodied relational understanding of persons.

Summary

Global health research ethics should be premised not upon passive accordance with existing guidelines on ethical conduct, but on tactile modes of knowing that rely upon being engaged with, and responsive to, research participants. Rather than focusing on the operationalization of ethical practice through forms and procedures, it is crucial that researchers recognize that each ethical dilemma encountered during fieldwork is unique and rooted in social contexts, interpersonal relationships, and personal narratives.
  相似文献   
55.
Given concerns that bilingual exposure might confuse children with disabilities—including autism spectrum disorder (ASD)—bilingual parents may restrict exposure to one language, often the community-dominant language. We investigated a potential consequence of this decision; the possibility that non-native language use might influence parental communicative behaviors during interaction with the child. We recruited 39 parent–child dyads, each with a young child with ASD (mostly boys) and parent/carer (mostly mothers). Parents were either monolingual speakers of community-dominant English (n = 20) or bilingual with English as the second language (n = 19). We confirmed our assumption that the latter group would have significantly poorer non-native English language via standardized assessment of expressive vocabulary, and ensured children were matched on age, ASD symptoms, and developmental level. We sampled parent–child interaction—including in each of bilinguals’ native and non-native languages—and coded parents’ amount and complexity of speech, communicative synchrony, and imitations and expansions of their child’s speech. Few differences presented across bilingual parents’ native versus non-native language samples, but this group showed reduced synchrony and use of expansions compared to monolinguals. Further, bilinguals’ English-language knowledge was associated with self-reported comfort using this language and with two coded interaction measures. These empirical data only partially support qualitative accounts that non-native language use may influence bilingual parents’ interaction behaviors with their young children. With growing rates of ASD diagnosis and increasing cultural/linguistic diversity around the world, further dedicated clinical and experimental attention to this issue is clearly warranted.  相似文献   
56.
57.
58.
59.
World Journal of Surgery - Guidelines call for cholecystectomy during the index hospitalization for patients with gallstone pancreatitis. Therefore, the study sought to determine the trends for...  相似文献   
60.
Sexual trauma is a national public health concern due to the alarming rates at which it occurs and decades of research supporting its long-term deleterious effects on health outcomes. We assessed the impact of gender norms and sexual trauma on power within sexual relationships among Latina immigrant farmworkers. At baseline, participants (N  = 175) completed a survey examining demographic information, sexual trauma history, and gender norms; a follow-up was administered 6 months later. Past sexual trauma was associated with less power in sexual relationships,  = −.25, < .001, as was endorsement of traditional Latina gender norms (i.e., marianismo): sexual relationship control,  = −.38, < .001; sexual decision-making dominance, r  = −.21,  = .005. In contrast, egalitarian gender norm endorsement was associated with higher levels of sexual relationship control,  = .37, < .001, and sexual decision-making dominance,  = .17,  = .023. Gender norms moderated the association between sexual trauma and sexual relationship power. Specifically, women who subscribed more to marianismo and reported sexual trauma had less decision-making dominance in sexual relationships, whereas those with lower ratings of marianismo reported higher levels of decision-making dominance despite sexual trauma, R2  = .03,  = .022. Sexual trauma history coupled with higher ratings of egalitarian gender norms was associated with higher levels of sexual relationship control, DR2  = .02,  = .023. These results highlight the importance of culturally informed research to increase the sexual and overall health of vulnerable populations (e.g., Latina immigrant farmworkers).  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