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   18133篇
  免费   1457篇
  国内免费   42篇
耳鼻咽喉   128篇
儿科学   695篇
妇产科学   523篇
基础医学   2312篇
口腔科学   229篇
临床医学   2048篇
内科学   3426篇
皮肤病学   305篇
神经病学   1971篇
特种医学   298篇
外国民族医学   5篇
外科学   1946篇
综合类   144篇
一般理论   67篇
预防医学   2739篇
眼科学   264篇
药学   1144篇
  1篇
中国医学   38篇
肿瘤学   1349篇
  2024年   43篇
  2023年   281篇
  2022年   485篇
  2021年   914篇
  2020年   551篇
  2019年   755篇
  2018年   860篇
  2017年   613篇
  2016年   629篇
  2015年   695篇
  2014年   901篇
  2013年   1149篇
  2012年   1592篇
  2011年   1613篇
  2010年   824篇
  2009年   664篇
  2008年   1132篇
  2007年   1194篇
  2006年   962篇
  2005年   898篇
  2004年   811篇
  2003年   725篇
  2002年   536篇
  2001年   70篇
  2000年   54篇
  1999年   58篇
  1998年   110篇
  1997年   75篇
  1996年   37篇
  1995年   48篇
  1994年   40篇
  1993年   39篇
  1992年   28篇
  1991年   17篇
  1990年   15篇
  1989年   20篇
  1987年   9篇
  1986年   14篇
  1985年   16篇
  1984年   15篇
  1983年   6篇
  1982年   10篇
  1981年   14篇
  1980年   16篇
  1978年   5篇
  1977年   9篇
  1976年   5篇
  1975年   7篇
  1974年   8篇
  1961年   5篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Animals establish their body plans in embryogenesis, but only a few animals can recapitulate this signaling milieu for regeneration after injury. In planarians, a pluripotent stem cell population and perpetual signaling of polarity axes collaborate to direct a steady replacement of cells during homeostasis and to power robust regeneration after even severe injuries. Several studies have documented the roles of conserved signaling pathways in maintaining and resetting axial polarity in planarians, but it is unclear how planarians reestablish polarity signaling centers after injury and whether these centers serve to influence identity decisions of stem cell progeny during their differentiation. Here we find that a planarian Follistatin homolog directs regeneration of anterior identity by opposing an Activin/ActR-1/Smad2/3 signaling pathway. Follistatin and Notum, a Wnt inhibitor, are mutually required to reestablish an anterior signaling center that expresses both cues. Furthermore, we show that the direction of cells down particular differentiation paths requires regeneration of this anterior signaling center. Just as its amphibian counterpart in the organizer signals body plan and cell fate during embryogenesis, planarian Follistatin promotes reestablishment of anterior polarity during regeneration and influences specification of cell types in the head and beyond.  相似文献   
102.
In this study, we used data from Add Health Waves II and III to compare men who had been incarcerated to those who had not, and examined whether incarceration was associated with increased numbers of sexual partners and increased odds of concurrent partnerships. We used multivariate regression and propensity-score matching to compare sexual behavior of Wave III male respondents who had been incarcerated with those who had not, and compared sexual behavior at Wave II to identify differences in sexual behavior prior to incarceration. Incarceration was associated with an increased rate of lifetime sexual partnership, but this was attenuated by substance use. Criminal justice involvement was associated with increased odds of having partners who report concurrent partnerships, but no further increase was seen with incarceration. There were no significant sexual behavior differences prior to incarceration. These results suggest that the criminal justice system and substance use may interact to shape sexual behavior.  相似文献   
103.
The antihypertensive and hypoglycemic effects of telmisartan, which has dual angiotensin II antagonist-PPAR-γ agonist properties, was studied in Cohen-Rosenthal Diabetic Hypertensive rats (CRDH), a model in which hypertension, insulin resistance, and diabetes co-exist. CRDH, Cohen-diabetic rats (CDR), and SHR received telmisartan (3 mg/kg/day in drinking water) for five months. Telmisartan significantly lowered systolic and diastolic BP in SHR and CRDH, independent of body weight, and remained fairly constant in controls throughout the experiment. Blood glucose levels fell rapidly in the treated animals and remained steady in controls. Results indicate that telmisartan is a prototype of a new approach to treating coexisting diabetes and hypertension.  相似文献   
104.
Abstract

The Hfe( - / - ) mouse is a model for human hereditary hemochromatosis (HHH). The accumulation of tissue iron in this condition has led to the suggestion that HHH patients may be at higher risk for neurodegenerative diseases. In this study, adult male Hfe( - / - ) mice and wildtype controls ( n = 12/group) were evaluated for impairment with motor tests (stride length, landing footsplay, rotarod) as well as a general observational battery (Functional Observational Battery, FOB). Hfe( - / - ) mice were characterized by more falls from the rotarod, wider forelimb landing footsplay and hypersensitivity to proximal stimulation. Iron accumulation in brain was not detected by histopathology. These data suggest that a motor syndrome may be associated with HHH that could be further understood through the Hfe( - / - ) mouse model.  相似文献   
105.
106.
107.
We developed an index to measure progressive realization for the human right to water and sanitation. While in this study we demonstrate its application to the non-discrimination and equality component for water, the conceptual approach of the index can be used for all the different components of the human right. The index was composed of one structural, one process, and two outcome indicators and is bound between −1 and 1, where negative values indicate regression and positive values indicate progressive realization. For individual structural and process indicators, only discrete values such as −1, −0.5, 0, 0.5, and 1 were allowed. For the outcome indicators, any value between −1 and 1 was possible, and a State's progress was evaluated using rates of change. To create an index that would allow for fair comparisons between States and across time, these rates of change were compared to benchmarked rates, which reflect the maximum rates a State can achieve. Using this approach, we calculated the index score for 56 States in 2010 for which adequate data were available and demonstrated that these index scores were not dependent on factors such as achieved level of coverage or gross national income. The proposed index differs from existing measures of inequality as it measures rate of change and not level of achievement, and thus addresses the principle of progressive realization that is fundamental to human rights.  相似文献   
108.
109.
110.
This article outlines the importance of assessing both within-child and environmental strengths for children and adolescents admitted to residential treatment facilities (RTFs). Discussed are the theoretical underpinnings behind strength-based assessment, as well as a number of organizations and initiatives that aim at raising the bar for children's care, creating a holistic viewpoint. Assessments such as the BASC-2, ASEBA, and Vineland-II are well-established measures that have moved to meet these demands, and measures like the BERS-2, RSCA, and DESSA have an overt strengths orientation. The CASA and the DCASC are omnibus strengths measures that can be utilized to fill the “intake gap.”  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