全文获取类型
收费全文 | 102586篇 |
免费 | 6359篇 |
国内免费 | 749篇 |
专业分类
耳鼻咽喉 | 1037篇 |
儿科学 | 3689篇 |
妇产科学 | 2436篇 |
基础医学 | 11849篇 |
口腔科学 | 1848篇 |
临床医学 | 8885篇 |
内科学 | 27768篇 |
皮肤病学 | 2039篇 |
神经病学 | 8643篇 |
特种医学 | 2602篇 |
外国民族医学 | 6篇 |
外科学 | 12086篇 |
综合类 | 2117篇 |
现状与发展 | 1篇 |
一般理论 | 25篇 |
预防医学 | 9701篇 |
眼科学 | 2670篇 |
药学 | 5900篇 |
3篇 | |
中国医学 | 445篇 |
肿瘤学 | 5944篇 |
出版年
2023年 | 916篇 |
2022年 | 1239篇 |
2021年 | 2469篇 |
2020年 | 1526篇 |
2019年 | 1768篇 |
2018年 | 4196篇 |
2017年 | 2926篇 |
2016年 | 2420篇 |
2015年 | 2392篇 |
2014年 | 2932篇 |
2013年 | 4046篇 |
2012年 | 6844篇 |
2011年 | 7381篇 |
2010年 | 3781篇 |
2009年 | 3423篇 |
2008年 | 6608篇 |
2007年 | 6536篇 |
2006年 | 5945篇 |
2005年 | 6156篇 |
2004年 | 6419篇 |
2003年 | 6185篇 |
2002年 | 5262篇 |
2001年 | 3395篇 |
2000年 | 2103篇 |
1999年 | 1697篇 |
1998年 | 1012篇 |
1997年 | 727篇 |
1996年 | 543篇 |
1995年 | 425篇 |
1994年 | 387篇 |
1993年 | 373篇 |
1992年 | 738篇 |
1991年 | 579篇 |
1990年 | 579篇 |
1989年 | 512篇 |
1988年 | 459篇 |
1987年 | 475篇 |
1986年 | 405篇 |
1985年 | 348篇 |
1984年 | 265篇 |
1983年 | 215篇 |
1982年 | 151篇 |
1979年 | 187篇 |
1978年 | 168篇 |
1977年 | 141篇 |
1975年 | 156篇 |
1974年 | 157篇 |
1973年 | 155篇 |
1972年 | 149篇 |
1971年 | 142篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
OBJECTIVES: Little information is available to incoming students in pediatrics residency programs on the experiences of past residents. The objective of this study was to investigate the pediatrics training programs and determine the professional outcomes of graduating residents between 1990 and 2000 in the Western Interregion. POPULATION AND METHODS: Questionnaires were distributed to the 187 medical students enrolled in pediatrics residency programs between 1990 and 2000 in the six university hospital centers of the Western Interregion. The questions concerned the details of training, the modes of residency positions, and current professional and personal situations. One hundred and sixty-five (88%) individuals responded. RESULTS: Seventy-seven percent of the practicing pediatricians stated that the training they had received during residency was adapted to their current practice. This percentage was higher for hospital staff physicians (82%) than for the physicians in private practice (50%) or those with salaried positions outside the hospital system (58%). One hundred and twenty-four had either completed post-residency training (97) or were doing so (27) at the time of the survey. All but one were professionally active, three quarters of them in hospitals and, of these, most were in the hospitals where they had trained. Eighty-six percent of the practicing pediatricians said they were satisfied with their professional work and 73% said they were satisfied with their personal lives. CONCLUSION: These results support the current reflection on reforming the residency training program in pediatrics, especially with regard to its prolongation and the diversification of the training options to take into account the individual student's professional orientation. 相似文献
93.
P. Moya E. Baixeras I. Barasoain J. M. Rojo E. Ronda M. L. Alonso A. Portol s 《Immunopharmacology and immunotoxicology》1987,9(2):243-256
The “in vivo” effect of Inmunoferon (AM3) on the production of interferon (IFN) and natural killer (NK) activity in young and old mice was studied. Although AM3 is not an IFN inducer by itself, enhancements in the serum IFN levels were produced when drug was associated to Newcastle disease virus or bacterial lipopo-lysaccharides as IFN inducers. This effect appeared to be dependent on the time lapsed between the inducer agent and drug. In addition, a significant stimulating effect on NK cell activity was also produced by AM3 treatments. This effect could be a consequence of a marked IFN induction and/or a modifying effect in prostaglandin synthesis. 相似文献
94.
95.
Cephalometric measurements in snorers, non-snorers, and patients with sleep apnoea. 总被引:7,自引:4,他引:3 下载免费PDF全文
Cephalometry is often used to assess patients with sleep apnoea but whether these measurements differ from those in non-apnoeic snorers and how they are influenced by age is not clear. Cephalometric radiographs of patients with sleep apnoea were compared with those of snorers without sleep apnoea and those of non-snorers. Fifty two snorers with suspected sleep apnoea had a conventional sleep study and were divided into two groups: those with an apnoea-hypopnoea index greater than 10/h (n = 40, sleep apnoea group) and those whose apnoea-hypopnoea index was 10/h or less (n = 12, snorer group). The cephalometric measurements in these patients were compared with those of 34 non-snoring control subjects. Controls were subdivided into two groups: control group 1 included 17 subjects similar in age to the sleep apnoea and snorer groups (mean (SD) age 50.0 (10.9), 50.7 (9.4), and 50.6 (9.7) years); control group 2 included 15 young men (25.4 (2.6) years). The distance from the mandibular plane to the hyoid bone (MP-H) and the length of the soft palate were greater in the patients with sleep apnoea (28.7 (7.8) and 43.6 (5.0) mm) than in the snorers (23.7 (4.2) and 40.3 (4.9 mm). The MP-H was similar in snorers and age matched control subjects, but was significantly greater in the older than in the younger control subjects (22.1 (6.1) vs 17.0 (6.8]. The soft palate was longer in subjects who snored (both sleep apnoea patients and snorers) than in control subjects. The MP-H distance significantly correlated with age for all subjects (snorers and controls) and for the control subjects alone. This study shows that non-apnoeic snorers have cephalometric abnormalities that differ from those of patients with sleep apnoea and that cephalometric values are influenced by the subject's age. 相似文献
96.
97.
98.
There is an inverse relationship between Mg balance and the ratio ionized Mg/total Mg in serum or plasma: in Mg excess, the ratio is decreased and in Mg deficiency the ratio is increased. It works as if a subtle homeostasic compensatory reaction modified the proportion of the most biologically active fraction of blood Mg in order to reduce the effects of Mg imbalance. Easy, available and unexpensive, the evaluation of total Mg in plasma or serum appears as a better marker than ionized Mg in Mg imbalance: it should be priviledged as the initial investigation in clinical practice. 相似文献
99.
R. Nickel S. Lau B. Niggemann C. Sommerfeld U. Wahn the German Multicenter Allergy Study Group 《Clinical and experimental allergy》2002,32(9):1274-1277
BACKGROUND: Bronchial responsiveness (BR) to histamine or methacholin is a common finding in adult non-asthmatic patients with allergic rhinitis. OBJECTIVE: We tested whether BR is also present in children with a comparatively short history of allergic rhinitis in a paediatric cohort. METHODS: We performed pulmonary function tests and histamine challenges in a total of 654 children (age 7 years, participants of the German Multicenter Allergy Study) and compared PC20 FEV1 values in children with asthma, allergic rhinitis, asymptomatic allergic sensitization and non-atopic controls. RESULTS: Most pronounced BR to histamine was observed in allergic asthmatics (n = 28), irrespective of the presence or absence of allergic rhinitis. Furthermore, PC(20)FEV(1) values in non-asthmatic children with allergic rhinitis (n = 24) were not significantly different from those seen in asymptomatic atopic (n = 54) or non-atopic controls (n = 92). CONCLUSIONS: In contrast to adult study populations, 7-year-old non-asthmatic children with allergic rhinitis do not show a higher degree of BR than asymptomatic atopic or non-atopic controls. Therefore, secondary preventive measures in non-asthmatic children with allergic rhinitis (such as regular local anti-inflammatory therapy or specific immunotherapy) should be studied and applied more intensely to prevent bronchial hyper-responsiveness (BHR) and asthma in this high-risk group. 相似文献
100.
Cora Rotary Pump for Implantable Left Ventricular Assist Device: Biomaterial Aspects 总被引:3,自引:0,他引:3
Abstract: Our group is developing a left ventricular assist device based on the principle of the Maillard-Wankel rotative compressor: it is a rotary, not centrifugal, pump that produces a pulsatile flow. Stringent requirements have been defined for construction materials. They must be light, yet sufficiently hard and rigid, and able to be machined with high precision. The friction coefficient must be low and the wear resistance high. The materials must be chemically inert and not deformable. Also, the materials must be biocompatible, and the blood contacting surface must be hemocompatible. We assessed the materials in terms of physiochemistry, mechanics, and tribology to select the best for hemocompatibility (determined by studies of protein adsorption: platelet, leukocyte, and red cell retention: and hemolysis, among other measurements) and biocompatibility (determined by measurement of complement activation and toxicity, among other criteria). Of the materials tested, for short- and middle-term assistance, we chose titanium alloy (Ti6 AI4 V) and alumina ceramic (Al2 O3 ) and for long-term and permanent use, composite materials (TiN coating on graphite). We saw that the polishing process of the substrate must be improved. For the future, the best coating material would be diamond-like carbon (DLC) or crystalline diamond coating. 相似文献