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   50913篇
  免费   5451篇
  国内免费   67篇
耳鼻咽喉   725篇
儿科学   1427篇
妇产科学   1401篇
基础医学   7750篇
口腔科学   1112篇
临床医学   6797篇
内科学   9512篇
皮肤病学   664篇
神经病学   4218篇
特种医学   1581篇
外国民族医学   1篇
外科学   6801篇
综合类   943篇
一般理论   42篇
预防医学   5360篇
眼科学   830篇
药学   4120篇
中国医学   65篇
肿瘤学   3082篇
  2022年   398篇
  2021年   901篇
  2020年   555篇
  2019年   921篇
  2018年   1033篇
  2017年   763篇
  2016年   913篇
  2015年   983篇
  2014年   1319篇
  2013年   2002篇
  2012年   2687篇
  2011年   2704篇
  2010年   1469篇
  2009年   1332篇
  2008年   2297篇
  2007年   2363篇
  2006年   2277篇
  2005年   2231篇
  2004年   2061篇
  2003年   1937篇
  2002年   1965篇
  2001年   1588篇
  2000年   1606篇
  1999年   1391篇
  1998年   641篇
  1997年   520篇
  1996年   443篇
  1995年   479篇
  1994年   446篇
  1993年   421篇
  1992年   1133篇
  1991年   1059篇
  1990年   1039篇
  1989年   955篇
  1988年   879篇
  1987年   904篇
  1986年   870篇
  1985年   890篇
  1984年   711篇
  1983年   602篇
  1982年   429篇
  1981年   348篇
  1980年   362篇
  1979年   578篇
  1978年   442篇
  1977年   361篇
  1976年   369篇
  1974年   379篇
  1973年   334篇
  1972年   338篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
Cognitive Therapy and Research - Despite interest in psychological inflexibility as a marker of suicide risk, no measure of psychological inflexibility specific to SI exists. The present study...  相似文献   
4.
5.
ABSTRACT

This project examined 55 picture books featuring transgender, gender expansive or genderqueer protagonists or narrators published between 2008 and 2018. The purpose of the study was to determine how this genre of children’s literature supports and challenges four gender assumptions: the gender binary, gender essentialism, sex/gender congruency and gender stability. Additionally, this critical analysis explored misgendering within this genre and themes of social rejection and acceptance. Protagonists and narrators were permitted a degree of gender nonconformity, however, the majority of picture books missed opportunities for a more complete exploration of gender possibilities.  相似文献   
6.

Background

There are well-established relationships between health and homelessness, and shelters can facilitate the transmission of diseases and contribute to their prevention. Adequate environmental health conditions and hygiene behaviors in homeless shelters are fundamental to the health of their clients, a marginalized population. We report the status of environmental health conditions and hygiene behaviors in homeless shelters and associated health outcomes; interventions to improve these conditions, behaviors, and outcomes; and obstacles to improvement.

Methods

PubMed, Web of Science, Scopus, and EBSCOhost were searched for peer-reviewed studies, and additional sources for grey literature. Studies were included if they reported primary data on one or more environmental health condition or hygiene behavior in homeless shelters.

Results

Twenty-eight studies were included in the review. Insufficient ventilation systems, unhygienic bedding, and overcrowding were the most documented environmental health and hygiene deficiencies in homeless shelters, and tuberculosis infections and skin diseases were the most documented associated health outcomes among clients. Studies frequently recommended or described implementation of behavioral and administrative controls, ventilation system improvements, and ultraviolet germicidal irradiation fixtures.

Discussion

Most studies addressed airborne transmission of tuberculosis and were conducted in high-income countries, revealing an imbalance in the literature. Insufficient resources and the transience of clients are barriers to improving hygiene behaviors and environmental conditions in homeless shelters. Further investment and research into ensuring adequate hygiene and environmental health in this setting can protect and promote the health and well-being of people experiencing homelessness.  相似文献   
7.
8.

Objective

Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.

Methods

Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.

Results

In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.

Conclusions

Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection.  相似文献   
9.
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment.  相似文献   
10.
As millions of people turn to social media for health information, better understanding the factors that guide health-related judgments and perceptions in this context is imperative. We report on two Web experiments (n > 400 total) examining the power of society’s widespread weight bias and related stereotypes to influence nutrition judgments in social media spaces. In Experiment 1, meals were judged as lower in nutritional quality when the person who recommended them (the source) was depicted as obese rather than of normal weight, an effect mediated by stereotypic beliefs about the source as a generally unhealthy person. Experiment 2 replicated this effect, which—notably—remained significant when controlling for objective nutritional information (calories and fat content). Results highlight spillover effects of weight bias that extend beyond person perception to color impressions of objects (here, food) that are associated with stigmatized attributes. Implications for everyday nutrition judgments and public health are considered.  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