全文获取类型
收费全文 | 13861篇 |
免费 | 1121篇 |
国内免费 | 100篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 574篇 |
妇产科学 | 358篇 |
基础医学 | 1645篇 |
口腔科学 | 344篇 |
临床医学 | 1489篇 |
内科学 | 3440篇 |
皮肤病学 | 257篇 |
神经病学 | 1306篇 |
特种医学 | 562篇 |
外国民族医学 | 8篇 |
外科学 | 1797篇 |
综合类 | 250篇 |
预防医学 | 1061篇 |
眼科学 | 289篇 |
药学 | 892篇 |
中国医学 | 3篇 |
肿瘤学 | 728篇 |
出版年
2021年 | 188篇 |
2020年 | 108篇 |
2019年 | 203篇 |
2018年 | 222篇 |
2017年 | 182篇 |
2016年 | 173篇 |
2015年 | 210篇 |
2014年 | 290篇 |
2013年 | 407篇 |
2012年 | 614篇 |
2011年 | 636篇 |
2010年 | 340篇 |
2009年 | 315篇 |
2008年 | 524篇 |
2007年 | 633篇 |
2006年 | 590篇 |
2005年 | 560篇 |
2004年 | 589篇 |
2003年 | 535篇 |
2002年 | 485篇 |
2001年 | 454篇 |
2000年 | 398篇 |
1999年 | 407篇 |
1998年 | 145篇 |
1997年 | 143篇 |
1996年 | 142篇 |
1995年 | 114篇 |
1994年 | 138篇 |
1993年 | 113篇 |
1992年 | 342篇 |
1991年 | 321篇 |
1990年 | 323篇 |
1989年 | 317篇 |
1988年 | 261篇 |
1987年 | 273篇 |
1986年 | 259篇 |
1985年 | 276篇 |
1984年 | 197篇 |
1983年 | 160篇 |
1982年 | 108篇 |
1979年 | 216篇 |
1978年 | 155篇 |
1977年 | 150篇 |
1976年 | 120篇 |
1975年 | 153篇 |
1974年 | 166篇 |
1973年 | 143篇 |
1972年 | 155篇 |
1971年 | 120篇 |
1970年 | 114篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
Valerie L. Blanco RDH MS Steven M. Levy DDS MPH Ronald L. Ettinger BDS MDS DDSc Henrietta Logan PhD Kathleen C. Buckwalter PhD RN 《Special care in dentistry》1997,17(4):129-132
Little is known about oral health care behaviors of community-dwelling, cognitively impaired elderly (CIE) persons. Few studies have been conducted regarding the actual provision of oral care for CIE persons or the attitudes and concerns about oral health among their caregivers. The CIE person's ability to perform self-care decreases over time, and the role of the caregiver in daily oral care becomes increasingly important. The purpose of this pilot study was to explore the attitudes toward oral health and identify related concerns among caregivers who care for community-dwelling CIE persons. Caregivers were surveyed by means of a self-administered, mailed questionnaire. To maintain confidentiality, an intermediary was used for recruitment and data collection. Overall, 148 caregivers were invited by an intermediary to participate in the survey; only 21 (14%) consented to participate and returned the questionnaire. This paper discusses some of the numerous methodological challenges identified when an attempt was made to survey caregivers' attitudes toward and barriers to providing oral care for a dependent CIE. 相似文献
14.
The Relationship Between Daily Life Stress and Gastrointestinal Symptoms in Women with Irritable Bowel Syndrome 总被引:3,自引:0,他引:3
Rona L. Levy Kevin C. Cain Monica Jarrett Margaret M. Heitkemper 《Journal of behavioral medicine》1997,20(2):177-193
Research on irritable bowel syndrome (IBS), a functional disorder of the gastrointestinal (GI) system, has linked GI symptoms to stress. This study examined the relationship between daily stress and GI symptoms across women and within woman in IBS patients (n = 26), IBS nonpatients (IBS-NP; n = 23), and controls (n = 26), controlling for menstrual cycle phase. Women (ages 20–45) completed daily health diaries for two cycles in which they monitored daily GI symptoms and stress levels. The Life Event Survey (LES) was used as a retrospective measure of self-reported stress. The across-women analyses showed higher mean GI symptoms and stress in the IBS and IBS-NP groups relative to controls but no group differences in LES scores. The within-woman analyses found a significant and positive relationship between daily stress and daily symptoms in both the IBS-NP and the IBS groups. Controlling for menstrual cycle had no substantial impact on the results. 相似文献
15.
D. Levy D. A. Deporter R. M. Pilliar P. A. Watson N. Valiquette 《Clinical oral implants research》1996,7(2):101-110
It has previously been reported that porous‐coated root form endosseous dental implants, became well integrated when used in the traditional 2‐stage surgical approach. In this study, the placement of the implant in a 1‐stage (non‐submerged)technique was to be explored. Implants were placed in the mandibles of dogs, and 2 designs were used differing only in that one (experimental) had a 3mm transgingival extension, permitting it to be exposed lo the oral cavity from the outset. 12 (3 per animal) non‐submerged implants were placed on I side of 4 beagle dogs and 12 control (submerged) implants were placed contralaterally. All implants were allowed to heal for 6 weeks, after which histological preparations were made. 2 of 12 non‐submerged implants were lost due to post‐operative complications: otherwise, all implants healed uneventfully. Histomorphometric analysis revealed bone‐implant contact, as assessed by absolute bone contact (ABC) and contact length fraction (CLF). to be greater for the submerged design, suggesting that bone healing may be delayed with the non‐submerged approach. As well. at this early stage of healing, for both implant designs, ABC and CLF were significantly greater on proximal than on buccal and lingual aspects. 相似文献
16.
S Levy 《The Journal of neuroscience》1992,12(6):2120-2129
Pacemaker cells of Aplysia californica display a regular bursting that results from a complex interplay of Ca(2+)-mediated conductances and a continuous influx and extrusion of Ca2+. The effect of the second messenger 1,4,5-inositol trisphosphate (InsP3) on intracellular free Ca2+ concentration (Cai) regulation and electrical properties was investigated in identified neurons of the abdominal ganglion (R15, L2-L4, L6). Double-barreled Ca-selective microelectrodes were used to pressure inject InsP3 and measure Cai at the same point. Brief injection of InsP3 resulted in an average increase of Cai of 9.2 +/- 10.0 microM (+/- SE; n = 14) that decayed in about 1 min. The InsP3-induced elevation of Cai increased in a dose-dependent manner and saturated when large amounts of InsP3 were injected. The InsP3-induced Cai increase was the result of mobilization from intracellular stores; Cai could be repeatedly mobilized by InsP3 in cells superfused with 0 Ca artificial seawater for more than 60 min. Following multiple injections of InsP3, there was no evidence of immediate inhibition or facilitation. the spatial nature of the InsP3-induced Cai increase was investigated by moving the double-barreled Ca-selective microelectrode tip in a stepwise manner relative to the membrane surface. The largest InsP3-induced Cai increases were measured in an area 0-80 microns from the membrane surface; some cells had their largest InsP3-induced Cai increase some 120-160 microns away from the membrane. Injection of InsP3 in a bursting neuron induced an immediate train of action potentials followed by membrane hyperpolarization and a decrease in the burst frequency. Injection of InsP3 in voltage-clamped cells induced a biphasic response: a rapid inward current followed by a more prolonged outward current; the temporal overlap of the currents was depth dependent. Injection of InsP3 or Ca2+ from a double-barreled injecting electrode induced currents that were different in waveform and time course, indicating that part of the conductance change induced by InsP3 is direct and not mediated by the mobilized Ca2+. In BAPTA [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'tetra-acetic acid]-loaded cells, the InsP3-induced inward current was mostly unaffected while the Ca-induced outward current was largely attenuated. The results suggest that InsP3 mobilizes Ca2+ from discrete intracellular compartments and induces distinct changes in membrane currents that seem to be independent of the Cai increase. 相似文献
17.
18.
Bilateral idiopathic inflammation of the optic nerve sheaths. Light and electron microscopic findings 总被引:1,自引:0,他引:1
Idiopathic perioptic neuritis is a term used to describe noninfectious inflammatory disorders of the optic nerve sheaths, the causes of which are unknown. In the following report, a 68-year-old woman with bilateral visual loss was found to have chronic inflammation with necrobiotic granulomas of her optic nerve sheaths. The patient, who had no systemic condition known to be associated with necrobiotic granuloma, lost vision from infarction of the optic nerve parenchyma and from compression due to thickened meninges. Although there are similarities between the inflammatory reaction in this case to the necrobiotic dermatoses, the pathogenesis of this condition remains obscure. 相似文献
19.
20.
P. Lambin A. Gervais M. Levy E. Defendini M. Dubarry P. Lebon P. Rouger E. Schuller 《Journal of neuroimmunology》1991,35(1-3):179-189
Serum and cerebrospinal fluid (CSF) of 50 neurological patients (24 multiple sclerosis (MS), ten acquired immunodeficiency syndrome (AIDS) and 16 other neurological diseases (OND)) and ten controls were analyzed by enzyme-linked immunosorbent assay (ELISA) for IgG subclass quantification and for the calculation of intrathecal synthesis (ITS). Total IgG was determined by two methods: electroimmunodiffusion (EID) and ELISA. A highly significant correlation was established between both methods. The existence of ITS was proved by the IgG/albumin ratio, the IgG index, Tourtellotte's formula, and Schuller's formula. In AIDS patients all IgG subclasses showed an increase in the CSF, whereas in sera only the IgG1 was significantly increased. CSF of MS patients showed a predominant increase of IgG1 whereas no significant modification of IgG subclasses was observed in sera. In most of the AIDS patients there was an ITS of IgG1, IgG3 and IgG4, but rarely (3/10) IgG2. In contrast, a polyclonal ITS of IgG was exceptional (1/24) in MS patients. No significant correlation could be established between clinical data and IgG subclass ITS in MS. The variations of each IgG subclass in serum and in ITS were not significantly correlated. Measurement of each IgG subclass and calculation of ITS seems essential in order to analyze any subclass antibody repertory inside the central nervous system. 相似文献