全文获取类型
收费全文 | 6802篇 |
免费 | 651篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 115篇 |
儿科学 | 172篇 |
妇产科学 | 147篇 |
基础医学 | 832篇 |
口腔科学 | 288篇 |
临床医学 | 775篇 |
内科学 | 1289篇 |
皮肤病学 | 214篇 |
神经病学 | 459篇 |
特种医学 | 206篇 |
外科学 | 1196篇 |
综合类 | 182篇 |
一般理论 | 8篇 |
预防医学 | 705篇 |
眼科学 | 60篇 |
药学 | 507篇 |
中国医学 | 5篇 |
肿瘤学 | 313篇 |
出版年
2021年 | 103篇 |
2020年 | 63篇 |
2019年 | 121篇 |
2018年 | 103篇 |
2017年 | 73篇 |
2016年 | 105篇 |
2015年 | 117篇 |
2014年 | 153篇 |
2013年 | 234篇 |
2012年 | 305篇 |
2011年 | 286篇 |
2010年 | 182篇 |
2009年 | 151篇 |
2008年 | 242篇 |
2007年 | 248篇 |
2006年 | 317篇 |
2005年 | 276篇 |
2004年 | 229篇 |
2003年 | 265篇 |
2002年 | 234篇 |
2001年 | 206篇 |
2000年 | 231篇 |
1999年 | 201篇 |
1998年 | 90篇 |
1997年 | 81篇 |
1996年 | 82篇 |
1995年 | 78篇 |
1994年 | 52篇 |
1993年 | 58篇 |
1992年 | 168篇 |
1991年 | 163篇 |
1990年 | 149篇 |
1989年 | 165篇 |
1988年 | 147篇 |
1987年 | 127篇 |
1986年 | 137篇 |
1985年 | 142篇 |
1984年 | 112篇 |
1983年 | 67篇 |
1982年 | 62篇 |
1981年 | 59篇 |
1979年 | 82篇 |
1978年 | 75篇 |
1977年 | 61篇 |
1976年 | 60篇 |
1974年 | 62篇 |
1973年 | 76篇 |
1971年 | 56篇 |
1970年 | 56篇 |
1969年 | 49篇 |
排序方式: 共有7473条查询结果,搜索用时 15 毫秒
101.
Diane Santa Maria Charlene A. Flash Sarah Narendorf Anamika Barman-Adhikari Robin Petering Hsun-Ta Hsu Jama Shelton Kimberly Bender Kristin Ferguson 《The Journal of adolescent health》2019,64(5):574-580
Purpose
Evidence suggests that young adults experiencing homelessness (YEH) are at elevated risk of HIV compared to housed youth. Given the limited research on pre-exposure prophylaxis (PrEP) awareness among YEH, this study examined their PrEP knowledge and attitudes.Methods
Data from a cross-sectional survey among YEH (ages 18–26) (n?=?1,427) in seven U.S. cities were used to assess their knowledge and attitudes regarding PrEP to inform HIV prevention efforts.Results
Participants were primarily male youth of color. The mean age was 20.9years. While 66% felt at risk for HIV, only 14% strongly agreed that they try to protect themselves from getting infected with HIV. Most (84%) were eligible for PrEP based on risk, yet only 29% had knowledge of PrEP. Despite this, 59% reported they were likely/extremely likely to take PrEP. Access to free PrEP (55%), HIV testing (72%), healthcare (68%), and one-on-one (62%), and text messaging support (57%) were rated as very/extremely important for PrEP uptake and adherence.Conclusions
The results of this study suggest missed opportunities to prevent new HIV infections among YEH. Efforts to increase PrEP uptake among this population should consider provider- and system-level interventions to increase PrEP awareness, decrease PrEP-associated healthcare costs, improve access to PrEP providers, and provide in-person and text messaging support. 相似文献102.
103.
E D Srivastava J R Barton S O'Mahony D I Phillips G T Williams N Matthews A Ferguson J Rhodes 《Gut》1991,32(9):1016-1019
Since ulcerative colitis predominantly affects non-smokers and ex-smokers we have examined the possibility that smoking modifies the humoral immune response to an antigenic challenge from the gut lumen. Gut lavage was used in healthy subjects and patients with ulcerative colitis, including both smokers and non-smokers. Antibodies in the intestinal fluid to Escherichia coli (five pooled serotypes), Candida albicans, gliadin, ovalbumin, and beta lactoglobulin were measured by ELISA to determine specific antibody concentrations of IgG, IgA, and IgM classes. Total IgG, IgA, and IgM were also measured in intestinal secretions and serum. In addition, circulating antibody concentrations of IgG, IgA, and IgM to three gut commensals - E coli (five pooled serotypes) C albicans, and Poroteus mirabilis were measured. There was a significant reduction in the IgA concentration in intestinal fluid of smokers with ulcerative colitis compared with healthy non-smoking controls. No other significant differences were found between the groups. Overall, these data are not consistent with the idea that smoking suppresses immune responses in the gut and suggest that the effect of smoking in colitis is mediated by another mechanism. 相似文献
104.
Alpha-myosin heavy chain: a sarcomeric gene associated with dilated and hypertrophic phenotypes of cardiomyopathy 总被引:1,自引:0,他引:1
105.
106.
D W Ferguson W J Berg P J Roach R M Oren A L Mark 《The American journal of cardiology》1992,69(5):523-531
Baroreflex control of heart rate, vascular resistance and norepinephrine is impaired in patients with heart failure, but recent animal studies demonstrate preserved baroreflex control of sympathetic nerve activity in this disorder. Studies were therefore performed to compare baroreflex control of efferent sympathetic nerve activity to muscle in 10 normal subjects (age mean +/- SEM 21 +/- 1 years) and in 11 patients with moderate to severe heart failure (age 48 +/- 5 years, New York Heart Association class II to IV, left ventricular ejection fraction 19 +/- 2%, pulmonary capillary wedge pressure 27 +/- 2 mm Hg, cardiac index 2.04 +/- 0.22 liters/min/m2). Baroreflex activation was produced by intravenous infusion of phenylephrine (0.5 to 2.0 micrograms/kg/min) and deactivation by infusion of nitroprusside (0.4 to 2.5 micrograms/kg/min). During phenylephrine infusion, comparable increases in mean arterial pressure were produced in normal subjects (89 +/- 2 to 99 +/- 3 mm Hg, p less than 0.01) and in patients with heart failure (90 +/- 2 to 99 +/- 3 mm Hg, p less than 0.01). The patients with heart failure exhibited significantly attenuated (p less than 0.01 for normal vs heart failure) decreases in heart rate (93 +/- 5 to 90 +/- 6 beats/min, p = not significant [NS]) compared with normal subjects (67 +/- 3 to 58 +/- 4 beats/min, p less than 0.01) and tended to demonstrate attenuated sympathoinhibitory responses to this pressor stimulus. More strikingly, patients with heart failure demonstrated significant impairment of baroreflex responses during nitroprusside-induced baroreceptor deactivation. In normal subjects, nitroprusside produced a decrease in mean arterial (90 +/- 2 to 80 +/- 3 mm Hg, p less than 0.001) and right atrial (4 +/- 1 to 2 +/- 1 mm Hg, p less than 0.01) pressures with a resultant reflex increase in heart rate (68 +/- 3 to 81 +/- 4 beats/min, p less than 0.001) and muscle sympathetic nerve activity (326 +/- 74 to 746 +/- 147 U/min, p less than 0.01). In patients with heart failure (n = 10), nitroprusside produced comparable (p = NS for normal vs heart failure) decreases in mean arterial (89 +/- 2 to 77 +/- 2 mm Hg, p less than 0.001) and right atrial (6 +/- 1 to 1 +/- 1 mm Hg, p less than 0.001) pressures, but did not significantly alter heart rate (91 +/- 6 to 97 +/- 4 beats/min, p = NS) or sympathetic nerve activity (936 +/- 155 to 1179 +/- 275 U/min, p = NS).(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
107.
S C Ridge K M Ferguson N Rath J Galivan J H Freisheim A L Oronsky S S Kerwar 《The Journal of rheumatology》1988,15(8):1193-1197
Passive transfer of adjuvant arthritis by spleen cells is suppressed by methotrexate. Mononuclear cells derived from spleens of normal and adjuvant arthritic Lewis rats were incubated with [3H]-methotrexate and harvested at various periods of time. The amount of methotrexate and its various polyglutamates were quantitated. The results of these studies indicate that the kinetics of uptake of methotrexate by mononuclear cells from normal and adjuvant arthritic rats are similar. However, the amount of methotrexate polyglutamates accumulating in the mononuclear cells of adjuvant arthritic rats was significantly lower than that observed in mononuclear cells derived from normal rats. 相似文献
108.
Zbigniew Binienda David L. Frederick Sherry A. Ferguson Robert L. Rountree Merle G. Paule Larry Schmued Syed F. Ali William Slikker Jr. Andrew C. Scallet 《Metabolic brain disease》1995,10(4):269-282
3-nitropropionic acid (3-NPA) neurotoxicity and long-term effects of perinatal hypoxia were evaluated in 18 adult rats. Hypoxia-insulted (I) and noninsulted (NI) rats were delivered by cesarean section. Hypoxic insult was effected by submerging dissected uterine horns in warmed saline for 15 min. NI rats were delivered from the adjacent nonsubmerged horns. At postnatal day 90, I and NI rats were trained to perform tasks thought to measure behaviors dependent upon aspects of time estimation (TE), motivation, and learning. At 12 months of age, rats were injected i.p. with escalating doses of 3-NPA (5 mg/kg/day to a maximum of 30 mg/kg/day) immediately after each test session and sacrificed at the end of treatment. Additional male rats were used as untreated controls. Although 3-NPA produced a dose-dependent impairment of performance in each task, the effects were qualitatively similar for each group. A significant difference between I and NI rats was, however, observed in the TE task where NI rats completed less of the task at high doses of 3-NPA compared to I rats. Compared to untreated controls, dopamine concentrations were decreased in caudate nucleus of both I and NI rats after 3-NPA. Specific areas most frequently damaged included cerebral cortex, hippocampal subfield CA1, thalamus, caudate nucleus, and the cerebellum. Lesions usually were less extensive in the I rather than NI members of a littermate pair, suggesting a possible protective effect of perinatal hypoxia against subsequent 3-NPA neurotoxicity. 相似文献
109.
Judith K. Ockene Rashelle B. Hayes Linda C. Churchill Sybil L. Crawford Denise G. Jolicoeur David M. Murray Abigail B. Shoben Sean P. David Kristi J. Ferguson Kathryn N. Huggett Michael Adams Catherine A. Okuliar Robin L. Gross Pat F. BassIII Ruth B. Greenberg Frank T. Leone Kola S. Okuyemi David W. Rudy Jonathan B. Waugh Alan C. Geller 《Journal of general internal medicine》2016,31(2):172-181
Background
Early in medical education, physicians must develop competencies needed for tobacco dependence treatment.Objective
To assess the effect of a multi-modal tobacco dependence treatment curriculum on medical students’ counseling skills.Design
A group-randomized controlled trial (2010–2014) included ten U.S. medical schools that were randomized to receive either multi-modal tobacco treatment education (MME) or traditional tobacco treatment education (TE).Setting/Participants
Students from the classes of 2012 and 2014 at ten medical schools participated. Students from the class of 2012 (N?=?1345) completed objective structured clinical examinations (OSCEs), and 50 % (N?=?660) were randomly selected for pre-intervention evaluation. A total of 72.9 % of eligible students (N?=?1096) from the class of 2014 completed an OSCE and 69.7 % (N?=?1047) completed pre and post surveys.Interventions
The MME included a Web-based course, a role-play classroom demonstration, and a clerkship booster session. Clerkship preceptors in MME schools participated in an academic detailing module and were encouraged to be role models for third-year students.Measurements
The primary outcome was student tobacco treatment skills using the 5As measured by an objective structured clinical examination (OSCE) scored on a 33-item behavior checklist. Secondary outcomes were student self-reported skills for performing 5As and pharmacotherapy counseling.Results
Although the difference was not statistically significant, MME students completed more tobacco counseling behaviors on the OSCE checklist (mean 8.7 [SE 0.6] vs. mean?8.0 [SE 0.6], p?=?0.52) than TE students. Several of the individual Assist and Arrange items were significantly more likely to have been completed by MME students, including suggesting behavioral strategies (11.8 % vs. 4.5 %, p?<?0.001) and providing information regarding quitline (21.0 % vs. 3.8 %, p?<?0.001). MME students reported higher self-efficacy for Assist, Arrange, and Pharmacotherapy counseling items (ps?≤0.05).Limitations
Inclusion of only ten schools limits generalizability.Conclusions
Subsequent interventions should incorporate lessons learned from this first randomized controlled trial of a multi-modal longitudinal tobacco treatment curriculum in multiple U.S. medical schools.NIH Trial Registry Number: NCT01905618110.
Katherine Smith Carmen Washington Jennifer Brown Alison Vadnais Laura Kroart Jacqueline Ferguson Joanna Cohen 《JMIR Public Health and Surveillance》2015,1(2)