全文获取类型
收费全文 | 64735篇 |
免费 | 6698篇 |
国内免费 | 1802篇 |
专业分类
耳鼻咽喉 | 428篇 |
儿科学 | 1614篇 |
妇产科学 | 1414篇 |
基础医学 | 4553篇 |
口腔科学 | 1534篇 |
临床医学 | 7162篇 |
内科学 | 10482篇 |
皮肤病学 | 788篇 |
神经病学 | 4124篇 |
特种医学 | 1029篇 |
外国民族医学 | 7篇 |
外科学 | 5807篇 |
综合类 | 10030篇 |
现状与发展 | 8篇 |
一般理论 | 1篇 |
预防医学 | 12150篇 |
眼科学 | 1119篇 |
药学 | 4657篇 |
48篇 | |
中国医学 | 1649篇 |
肿瘤学 | 4631篇 |
出版年
2024年 | 265篇 |
2023年 | 1266篇 |
2022年 | 2606篇 |
2021年 | 3412篇 |
2020年 | 3286篇 |
2019年 | 2437篇 |
2018年 | 2444篇 |
2017年 | 2518篇 |
2016年 | 2826篇 |
2015年 | 2578篇 |
2014年 | 4842篇 |
2013年 | 5340篇 |
2012年 | 4433篇 |
2011年 | 4553篇 |
2010年 | 3504篇 |
2009年 | 3209篇 |
2008年 | 3070篇 |
2007年 | 2977篇 |
2006年 | 2597篇 |
2005年 | 2252篇 |
2004年 | 1801篇 |
2003年 | 1567篇 |
2002年 | 1310篇 |
2001年 | 1127篇 |
2000年 | 941篇 |
1999年 | 741篇 |
1998年 | 667篇 |
1997年 | 608篇 |
1996年 | 467篇 |
1995年 | 442篇 |
1994年 | 405篇 |
1993年 | 315篇 |
1992年 | 316篇 |
1991年 | 298篇 |
1990年 | 224篇 |
1989年 | 201篇 |
1988年 | 179篇 |
1987年 | 136篇 |
1986年 | 132篇 |
1985年 | 165篇 |
1984年 | 147篇 |
1983年 | 94篇 |
1982年 | 111篇 |
1981年 | 93篇 |
1980年 | 74篇 |
1979年 | 61篇 |
1978年 | 42篇 |
1977年 | 39篇 |
1976年 | 43篇 |
1975年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
Marc G Weisskopf Honglei Chen Michael A Schwarzschild Ichiro Kawachi Alberto Ascherio 《Movement disorders》2003,18(6):646-651
Anxiety disorders are common in Parkinson's disease (PD). However, the risk of PD among people with anxiety has not been examined in a prospective cohort study. We examined this relation prospectively within the Health Professionals Follow-Up Study, a cohort of US male health professionals. In 1988, anxiety was assessed using the Crown-Crisp phobic anxiety index in 35,815 men without PD, stroke, or cancer at baseline. There were 189 incident cases of PD during 12 years of follow-up. After adjusting for age, smoking, and caffeine intake, the relative risk of PD among men with the highest level of anxiety (Crown-Crisp index scores of 4 and above) was 1.5 (95% CI = 1.0-2.1; P-trend = 0.01) compared to men with the lowest level of anxiety. This positive association persisted after excluding cases of PD with onset in the first 2 years of follow-up. Use of anxiolytic medication was also associated with an elevated risk of PD (RR= 1.6; 95% CI = 0.9-3.1), but adjusting for this potential confounder did not materially affect the association between anxiety and risk of PD. Our results suggest that anxiety is a risk factor for PD. Whether this association is causal or the result of shared underlying biology remains a question. 相似文献
73.
人的社会能力和适应性的影响因素研究 总被引:5,自引:0,他引:5
目的:探讨影响人的社会能力和适应性的主要因素。方法:应用世界卫生组织提供的量表进行问卷调查,并对资料进行单因素及多元逐步回归分析。结果:男性、城市环境、青壮年、非政府职员职业、较高文化程度、已婚、较好经济收入、医疗保险及较低医疗费用会对社会能力和适应性产生积极影响。结论:年龄、家庭年收入、家庭年医疗费用及文化程度是社会能力和适应性的重要影响因素。 相似文献
74.
Dr. Harvey I. Pass MD Karen Kranda RN Barbara K. Temeck MD Irwin Feuerstein MD Seth M. Steinberg PhD 《Annals of surgical oncology》1997,4(3):215-222
Background: We analyzed morbidity and mortality, sites of recurrence, and possible prognostic factors in 95 (78 male, 17 female) patients
with MPM on phase I–III trials since 1990. A debulking resection to a requisite, residual tumor thickness of ≤ 5 mm was required
for inclusion.
Methods: Preoperative tumor volumes were determined by three-dimensional reconstruction of chest computerized tomograms. Pleurectomy
(n=39) or extrapleural pneumonectomy (EPP; n=39) was performed. Seventeen patients could not be debulked. Preoperative EPP
platelet counts (404,000) and mean tumor volume (491 cm3) were greater than that seen for pleurectomy (344,000, 114 cm3).
Results: Median survival for all patients was 11.2 months, with that for pleurectomy 14.5 months, that for EPP 9.4 months, and that
for unresectable patients 5.0 months. Arrhythmia (n=14; 15%) was the most common complication, and there were two deaths related
to surgery (2.0%). Tumor volume of >100 ml, biphasic histology, male sex, and elevated platelet count were associated with
decreased survival (p<0.05). Both EPP and pleurectomy had equivalent recurrence rates (27 of 39 [69%] and 31 of 39 [79%],
respectively); however, 17 of 27 EPP recurrences as opposed to 28 of 31 pleurectomy recurrences were locoregional (p2=0.013).
Conclusions: Debulking resections for MPM can be performed with low operative mortality. Size and platelet count are important preoperative
prognostic parameters for MPM. Patients with poor prognostic indicators should probably enter nonsurgical, innovative trials
where toxicity or response to therapy can be evaluated.
Presented at the 49th Annual Cancer Symposium of The Society of Surgical Oncology, Atlanta, Georgia, March 21–24, 1996. 相似文献
75.
76.
Cardia: study design, recruitment, and some characteristics of the examined subjects 总被引:28,自引:0,他引:28
Gary D. Friedman Gary R. Cutter Richard P. Donahue Glenn H. Hughes Stephen B. Hulley David R. Jacobs Jr. Kiang Liu Peter J. Savage 《Journal of clinical epidemiology》1988,41(11):1105-1116
In 1984, a prospective cohort study, Coronary Artery Risk Development in Young Adults (CARDIA) was initiated to investigate life-style and other factors that influence, favorably and unfavorably, the evolution of coronary heart disease risk factors during young adulthood. After a year of planning and protocol development, 5,116 black and white women and men, age 18-30 years, were recruited and examined in four urban areas: Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota, and Oakland, California. The initial examination included carefully standardized measurements of major risk factors as well as assessments of psychosocial, dietary, and exercise-related characteristics that might influence them, or that might be independent risk factors. This report presents the recruitment and examination methods as well as the mean levels of blood pressure, total plasma cholesterol, height, weight and body mass index, and the prevalence of cigarette smoking by age, sex, race and educational level. Compared to recent national samples, smoking is less prevalent in CARDIA participants, and weight tends to be greater. Cholesterol levels are representative and somewhat lower blood pressures in CARDIA are probably, at least in part, due to differences in measurement methods. Especially noteworthy among several differences in risk factor levels by demographic subgroup, were a higher body mass index among black than white women and much higher prevalence of cigarette smoking among persons with no more than a high school education than among those with more education. 相似文献
77.
1600例住院病人死亡原因分析 总被引:1,自引:0,他引:1
[目的 ]探讨 160 0例住院病人的死亡原因及其分布特征 .[方法 ]收集 1995年 1月至 2 0 0 2年12月间 160 0例我院住院死亡病人资料 ,对死亡疾病构成比率、男女主要疾病死亡构成比率、汉族和朝鲜族主要疾病死亡构成比率及年龄构成比率进行统计 .[结果 ] 160 0例死亡病例的死亡原因中脑血管疾病占 2 4 9% ,恶性肿瘤占 2 3 4% ,消化系统疾病占 13 7% ,意外伤害和中毒占 10 3 % ,心血管疾病占9 2 % ;男性与女性主要疾病死亡分布不同 ,两者间有非常显者性差异 ;汉族与朝鲜族主要疾病死亡分布不同 ,两者间亦有非常显者性差异 ;年龄构成比中 61~ 70岁居首位 ,占 2 6 6% ,51~ 60岁占 18 0 % ,41~ 50岁占 16 8% ,71~ 80岁占 15 8% ,3 1~ 40岁占 10 8% .[结论 ]住院死亡的疾病构成因性别及民族不同 ,其分布不同 相似文献
78.
BACKGROUND: Since chronic infection with mucoid Pseudomonas aeruginosa (PA) is associated with deteriorating lung function, many parents of young children with cystic fibrosis (CF) fear the first PA positive throat swab as a milestone in the progression of the disease. To reduce the risk of PA acquisition from the environment, they perform preventive measures at home or outdoors. METHODS: In an attempt to evaluate the attitude of CF physicians towards these measures and the respective consulting practice, we mailed a questionnaire to all 65 certified paediatric CF centres in Germany. RESULTS: Physicians from 54 (83%) CF clinics replied. They expressed widely different ideas about the impact of the environment for the acquisition of P. aeruginosa, and recommended a large spectrum of preventive measures. Some physicians proposed only few precautions, which focussed on the prevention of cross-infection between patients, whereas others suggested prevention of any contact with moist or wet places, e.g. use different toothbrushes for mornings and evenings, or do without air-conditioning in the car. CONCLUSIONS: CF physicians have different opinions on the risk of PA acquisition from the environment. Doctors who recommend strict precautions could engender a parental fear of a ubiquous threat from invisible bacteria. The resulting extended safety measures might impair the family's quality of life. 相似文献
79.
Satoshi Ogata Takayuki Naito Noriaki Yorioka Kei Kiribayashi Masatoshi Kuratsune Nobuoki Kohno 《Nephrology, dialysis, transplantation》2004,19(11):2831-2837
BACKGROUND: In patients on long-term continuous ambulatory peritoneal dialysis (CAPD), peritoneal dysfunction may occur due to loss of peritoneal mesothelial cells, peritoneal fibrosis and neovascularization. Lactate, long used as a buffer in peritoneal dialysates, has been substituted by bicarbonate in recent years. However, their effects on the peritoneum of CAPD patients are unknown. This study investigated the influence of lactate and bicarbonate on peritoneal dysfunction in CAPD patients. METHODS: The mitochondrial activity of human peritoneal mesothelial cells (HPMCs) and their expression of basic fibroblast growth factor (bFGF) were studied after culture under various conditions. We also assessed the mitochondrial-activating effect of the supernatant of those cultures on human peritoneal fibroblasts (HPFBs) and human umbilical vein endothelial cells (HUVECs) and the effect of recombinant human bFGF on the mitochondrial activity of HPFBs and HUVECs. We used the WST-1 assay to determine mitochondrial activity in HPMC. RESULTS: At pH 7.4, the mitochondrial activity of HPMCs was lowest in a medium containing 40 mM (Lac), intermediate in a lactate (15 mM) plus bicarbonate (25 mM) medium (Lac/Bic), and highest in a 40 mM bicarbonate medium (Bic). In culture supernatant, the increase of bFGF was: Lac > Lac/Bic > Bic. Mitochondrial activation of HPFBs and HUVECs was stimulated by HPMC culture supernatants in the following decreasing order: Lac > Lac/Bic > Bic. The effects of these supernatants were suppressed by a bFGF-neutralizing antibody, while recombinant bFGF caused concentration-dependent mitochondrial activation in HPFBs and HUVECs. CONCLUSIONS: The role of bFGF in peritoneal fibrosis and neovascularization may be important. A bicarbonate-containing medium is better than a lactate-containing medium for preserving cell viability in HPMCs and preventing bFGF expression by these cells. 相似文献
80.
上消化道出血798例分析 总被引:33,自引:0,他引:33
目的 探讨上消化道出血的病因和相关因素。方法 回顾性分析我院 8年来 798例上消化道出血病人的临床资料。结果 男性并发上消化道出血占 80 .2 0 %、女性占 19.80 % ,男性明显高于女性 (χ2 =6 .5 6 ,P <0 .0 5 ) ;青年人、中年人及老年人各占 2 7.82 %、5 7.6 1%和 14 .5 7% (P <0 .0 1) ,老年人合并重度上消化道出血多见 ;不同性别、年龄者出血的原因不尽相同。结论 上消化道出血的病人以消化性溃疡、胃癌、急性胃粘膜损害、食道胃底静脉曲张为最常见的病因 ,性别、年龄等均为上消化道出血的相关因素 相似文献