全文获取类型
收费全文 | 2549篇 |
免费 | 188篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 96篇 |
妇产科学 | 52篇 |
基础医学 | 429篇 |
口腔科学 | 31篇 |
临床医学 | 378篇 |
内科学 | 483篇 |
皮肤病学 | 22篇 |
神经病学 | 234篇 |
特种医学 | 106篇 |
外科学 | 203篇 |
综合类 | 37篇 |
一般理论 | 6篇 |
预防医学 | 266篇 |
眼科学 | 33篇 |
药学 | 167篇 |
中国医学 | 2篇 |
肿瘤学 | 181篇 |
出版年
2023年 | 20篇 |
2022年 | 21篇 |
2021年 | 59篇 |
2020年 | 26篇 |
2019年 | 50篇 |
2018年 | 58篇 |
2017年 | 51篇 |
2016年 | 47篇 |
2015年 | 67篇 |
2014年 | 61篇 |
2013年 | 114篇 |
2012年 | 185篇 |
2011年 | 210篇 |
2010年 | 129篇 |
2009年 | 94篇 |
2008年 | 171篇 |
2007年 | 197篇 |
2006年 | 163篇 |
2005年 | 166篇 |
2004年 | 165篇 |
2003年 | 136篇 |
2002年 | 144篇 |
2001年 | 20篇 |
2000年 | 18篇 |
1999年 | 12篇 |
1998年 | 25篇 |
1997年 | 21篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 19篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1964年 | 8篇 |
1962年 | 9篇 |
排序方式: 共有2742条查询结果,搜索用时 62 毫秒
101.
Druse MJ Tajuddin NF Gillespie RA Dickson E Atieh M Pietrzak CA Le PT 《Brain research. Developmental brain research》2004,150(2):79-88
Previously, this laboratory showed that in utero and in vitro ethanol exposure significantly reduces developing serotonin (5-HT) neurons and that treatment with a 5-HT1A agonist such as buspirone or ipsapirone prevents the ethanol-associated loss. The present study investigated whether ethanol decreases fetal rhombencephalic neurons, including 5-HT neurons, by causing apoptosis. We also investigated whether ipsapirone prevents the ethanol-associated deficit of fetal rhombencephalic neurons by reducing apoptosis. The results of these studies strongly suggest that the ethanol-associated reduction in fetal rhombencephalic neurons that accompanies both in utero and in vitro exposure to physiological concentrations of ethanol is associated with increased apoptosis in these neurons. A physiological concentration of ethanol (i.e., 50 mM) increases apoptosis in fetal rhombencephalic neurons and decreases the number 5-HT neurons. It also appears that the 5-HT1A agonist ipsapirone provides neuroprotection to these neurons by reducing apoptosis. Another mechanism by which ethanol-associated apoptosis can be blocked is by including serum proteins in the media at a concentration of 1% or higher; this concentration of serum proteins is high in comparison to the protein concentration in cerebrospinal fluid. 相似文献
102.
Chouraqui Jean-Pierre Tavoularis Gabriel Simeoni Umberto Ferry Constance Turck Dominique 《European journal of nutrition》2020,59(1):67-80
European Journal of Nutrition - The French Nutri-Bébé 2013 study aimed to assess the nutritional intake of infants and young children in comparison with the recommendations of the 2013... 相似文献
103.
104.
Eric J. Chow Amanda M. Casto Reigran Sampoleo Margaret G. Mills Peter D. Han Hong Xie Brian Pfau Tien V. Nguyen Jaydee Sereewit Julia H. Rogers Sarah N. Cox Melissa A. Rolfes Constance Ogokeh Emily Mosites Timothy M. Uyeki Alexander L. Greninger James P. Hughes M. Mia Shim Nancy Sugg Jeffrey S. Duchin Lea M. Starita Janet A. Englund Pavitra Roychoudhury Helen Y. Chu 《Emerging infectious diseases》2022,28(11):2343
To determine the epidemiology of human parainfluenza virus in homeless shelters during the COVID-19 pandemic, we analyzed data and sequences from respiratory specimens collected in 23 shelters in Washington, USA, during 2019–2021. Two clusters in children were genetically similar by shelter of origin. Shelter-specific interventions are needed to reduce these infections. 相似文献
105.
The Vancouver Lymphadenopathy-AIDS Study: 5. Antecedent behavioural, clinical and laboratory findings in patients with AIDS and HIV-seropositive controls. 下载免费PDF全文
W J Boyko M T Schechter K J Craib P Constance R Nitz S Fay A McLeod M O'Shaughnessy 《Canadian Medical Association journal》1986,135(8):881-887
In a group of homosexual men in Vancouver studied prospectively since November 1982, 26 cases of acquired immune deficiency syndrome (AIDS) have arisen. To identify behavioural, clinical and laboratory findings that might predict the development of AIDS in people with antibody to human immunodeficiency virus (HIV), we compared data for 25 patients with AIDS with corresponding data for 80 controls serologically positive for HIV selected from the cohort. The clinical and laboratory data for the patients with AIDS preceded the diagnosis of the syndrome by a mean of 17.5 months. The controls had been both seropositive and AIDS-free for a mean of 16.7 months after acquisition of their data. We detected significant differences between the patients with AIDS and the controls in IgG and IgA levels, absolute number of helper T cells and ratio of helper to suppressor T cells but not in lifetime number of male sexual partners, frequency of receptive anal intercourse or receptive fisting, illicit drug use or history of infectious disease. We also detected an increased risk of AIDS among those who had an elevated number of sexual contacts in AIDS-endemic areas in the 5 years before enrollment. A history of increased early sexual contact in AIDS-endemic areas is likely to be associated with early infection and with an increased risk of AIDS among men with HIV infection of unknown duration. Thus, although our analysis had limited statistical power, we conclude that most lifestyle variables appear to act as exposure factors in HIV infection but not as cofactors in the development of AIDS. 相似文献
106.
The Vancouver Lymphadenopathy-AIDS Study: 4. Effects of exposure factors, cofactors and HTLV-III seropositivity on number of helper T cells. 总被引:1,自引:0,他引:1 下载免费PDF全文
M T Schechter W J Boyko E Jeffries B Willoughby R Nitz P Constance M Weaver B Wiggs M O''Shaughnessy 《Canadian Medical Association journal》1985,133(4):286-292
Results of testing for antibody to human T-lymphotropic virus (HTLV-III) and absolute numbers of helper T cells in 219 participants in the Vancouver Lymphadenopathy-AIDS (acquired immune deficiency syndrome) Study were analysed. The mean absolute helper T-cell counts in the 141 HTLV-III seronegative and the 78 seropositive men were 897/mL and 659/mL respectively (p less than 0.001). Established AIDS risk factors such as elevated lifetime number of male sexual partners and frequent receptive anal intercourse did not appear to have any significant effect on number of helper T cells that was independent of HTLV-III antibody status. Seropositive men with less than 100, 100 to 500 or more than 500 male sexual partners in their lifetime had mean absolute helper T-cell counts of 667/mL, 651/mL and 662/mL respectively. Most other risk factors, as well, did not appear to exert any effect on absolute number of helper T cells that was independent of the effect of HTLV-III antibody status. However, independent effects of a history of mononucleosis or hepatitis and of cigarette smoking were noted. The data support the hypothesis that no immune dysfunction beyond that due to the initial infection alone arises from repeated exposure to HTLV-III. Most risk factors appear to act as exposure factors, exerting their effect on the immune system merely by increasing the probability of contact with the agent. The independent effects of a history of mononucleosis or hepatitis suggest that viral agents may be cofactors in the production of immune dysfunction. 相似文献
107.
Constance Tucker Beth Choby Andrew Moore Robert Scott Parker II Benjamin R. Zambetti Sarah Naids 《Teaching and learning in medicine》2017,29(4):373-377
This Conversations Starter article presents a selected research abstract from the 2017 Association of American Medical Colleges Southern Region Group on Educational Affairs annual spring meeting. The abstract is paired with the integrative commentary of 4 experts who shared their thoughts stimulated by the study. These thoughts explore the value of the Observed Structured Teaching Encounter in providing structured opportunities for medical students to engage with the complexities of providing peer feedback on professionalism. 相似文献
108.
Patrick Peretti-Watel Jean Constance Valérie Seror & François Beck 《Addiction (Abingdon, England)》2009,104(10):1718-1728
Aims This paper aimed to assess whether the increase of social differentiation of smoking is observed in France.
Design and setting Five cross-sectional telephone surveys conducted in France between 2000 and 2007.
Participants The surveys were conducted among national representative samples of French subjects aged 18–75 years ( n = 12 256, n = 2906, n = 27 499, n = 2887, n = 6007 in 2000, 2003, 2005, 2006 and 2007, respectively). We focused on three groups: executives, manual workers and the unemployed.
Measurements Time trends of smoking prevalence were assessed, and socio-economic factors (especially occupation and job status) associated with smoking were identified and compared in 2000 and 2005. We also computed respondents' equivalized household consumption (EHI) and their cigarette budget to assess the financial burden of smoking.
Findings Between 2000 and 2007, smoking prevalence decreased by 22% among executive managers and professionals and by 11% among manual workers, and did not decrease among the unemployed. Indicators of an underprivileged social situation were associated more markedly with smoking in 2005 than in 2000. In addition, the falling-off of smoking initiation occurred later and was less marked among manual workers than it was among executive managers and professionals. Finally, in 2005 15% of French smokers devoted at least 20% of their EHI to the purchase of cigarettes, versus only 5% in 2000, and smoking weighted increasingly heavily on the poorest smokers' budgets.
Conclusions While these results point out an increased social differentiation in tobacco use, they underline the need to design and implement other forms of action to encourage people to quit, in particular targeting individuals belonging to underprivileged groups. 相似文献
Design and setting Five cross-sectional telephone surveys conducted in France between 2000 and 2007.
Participants The surveys were conducted among national representative samples of French subjects aged 18–75 years ( n = 12 256, n = 2906, n = 27 499, n = 2887, n = 6007 in 2000, 2003, 2005, 2006 and 2007, respectively). We focused on three groups: executives, manual workers and the unemployed.
Measurements Time trends of smoking prevalence were assessed, and socio-economic factors (especially occupation and job status) associated with smoking were identified and compared in 2000 and 2005. We also computed respondents' equivalized household consumption (EHI) and their cigarette budget to assess the financial burden of smoking.
Findings Between 2000 and 2007, smoking prevalence decreased by 22% among executive managers and professionals and by 11% among manual workers, and did not decrease among the unemployed. Indicators of an underprivileged social situation were associated more markedly with smoking in 2005 than in 2000. In addition, the falling-off of smoking initiation occurred later and was less marked among manual workers than it was among executive managers and professionals. Finally, in 2005 15% of French smokers devoted at least 20% of their EHI to the purchase of cigarettes, versus only 5% in 2000, and smoking weighted increasingly heavily on the poorest smokers' budgets.
Conclusions While these results point out an increased social differentiation in tobacco use, they underline the need to design and implement other forms of action to encourage people to quit, in particular targeting individuals belonging to underprivileged groups. 相似文献
109.
Kathleen W. Saunders Kate M. Dunn Joseph O. Merrill Mark Sullivan Constance Weisner Jennifer Brennan Braden Bruce M. Psaty Michael Von Korff 《Journal of general internal medicine》2010,25(4):310-315