全文获取类型
收费全文 | 11500篇 |
免费 | 1121篇 |
国内免费 | 77篇 |
专业分类
耳鼻咽喉 | 178篇 |
儿科学 | 379篇 |
妇产科学 | 210篇 |
基础医学 | 1475篇 |
口腔科学 | 103篇 |
临床医学 | 1453篇 |
内科学 | 2641篇 |
皮肤病学 | 116篇 |
神经病学 | 1121篇 |
特种医学 | 443篇 |
外科学 | 1912篇 |
综合类 | 126篇 |
一般理论 | 4篇 |
预防医学 | 863篇 |
眼科学 | 401篇 |
药学 | 622篇 |
中国医学 | 7篇 |
肿瘤学 | 644篇 |
出版年
2023年 | 121篇 |
2022年 | 211篇 |
2021年 | 440篇 |
2020年 | 226篇 |
2019年 | 359篇 |
2018年 | 432篇 |
2017年 | 317篇 |
2016年 | 347篇 |
2015年 | 377篇 |
2014年 | 482篇 |
2013年 | 616篇 |
2012年 | 922篇 |
2011年 | 892篇 |
2010年 | 474篇 |
2009年 | 425篇 |
2008年 | 682篇 |
2007年 | 637篇 |
2006年 | 574篇 |
2005年 | 567篇 |
2004年 | 499篇 |
2003年 | 407篇 |
2002年 | 363篇 |
2001年 | 114篇 |
2000年 | 93篇 |
1999年 | 77篇 |
1998年 | 88篇 |
1997年 | 73篇 |
1996年 | 58篇 |
1995年 | 43篇 |
1994年 | 55篇 |
1993年 | 42篇 |
1992年 | 88篇 |
1991年 | 62篇 |
1990年 | 73篇 |
1989年 | 67篇 |
1988年 | 73篇 |
1987年 | 94篇 |
1986年 | 87篇 |
1985年 | 79篇 |
1984年 | 70篇 |
1983年 | 65篇 |
1982年 | 68篇 |
1981年 | 56篇 |
1979年 | 55篇 |
1978年 | 45篇 |
1977年 | 36篇 |
1976年 | 42篇 |
1974年 | 47篇 |
1973年 | 40篇 |
1972年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Timothy J Halligan Nathan G Russell William J Dunn Steven J Caldroney Timothy B Skelton 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2005,100(6):688-692
Scurvy is a nondiscriminatory disease process resulting from a nutritional deficiency of ascorbic acid (vitamin C). The severe vitamin deficiency produces a breakdown in the cellular structure of the body. This case report describes a middle-age woman with a history of edema, bruising of the lower extremities, anemia, and severe periodontal disease. Her presentation and medical history are classic for the signs of scurvy. Scurvy is now only uncommonly seen in developed countries, but there are still vulnerable populations whose nutritional status can lead to scurvy. The aim of this report is to help the clinician identify and treat scurvy, a disease that was once feared for its high mortality but is now easily treatable, even in cases that have progressed to multiple organ dysfunction and failure. 相似文献
12.
A F Shorr J L Wainright C S Cors C J Lettieri S D Nathan 《The European respiratory journal》2007,30(4):715-721
Pulmonary hypertension (PH) may complicate idiopathic pulmonary fibrosis (IPF) but the prevalence of PH in IPF remains undefined. The present authors sought to describe the prevalence of PH in IPF. The lung transplant registry for the USA (January 1995 to June 2004) was analysed and IPF patients who had undergone right heart catheterisation (RHC) were identified. PH was defined as a mean pulmonary arterial pressure ((Ppa)) > or =25 mmHg and severe PH as a (Ppa) >40 mmHg. Independent factors associated with PH were determined. Of the 3,457 persons listed, 2,525 (73.0%) had undergone RHC. PH affected 46.1% of subjects; approximately 9% had severe PH. Variables independently associated with mild-to-moderate PH were as follows: need for oxygen, pulmonary capillary wedge pressure (P(pcw)) and forced expiratory volume in one second (FEV(1)). Independent factors related to severe PH included the following: carbon dioxide tension, age, FEV(1), P(pcw), need for oxygen and ethnicity. A sensitivity analysis in subjects with P(pcw) <15 mmHg did not appreciably alter the present findings. Pulmonary hypertension is common in idiopathic pulmonary fibrosis patients awaiting lung transplant, but the elevations in mean pulmonary arterial pressure are moderate. Lung volumes alone do not explain the pulmonary hypertension. Given the prevalence of pulmonary hypertension and its relationship with surrogate markers for quality of life (e.g. activities of daily living), future trials of therapies for this may be warranted. 相似文献
13.
14.
The clinical records of five men who had sexually assaulted women aged 60 or over were compared to the records of seven men who had sexually assaulted younger victims. Details of childhood adjustment, psychiatric and criminal histories, psychiatric diagnosis, psychological assessment findings, and offence characteristics were examined to determine psychological and social factors specifically associated with the sexual assault of older women. The findings suggest that when victims are older women, the sexual assault is likely to be particularly brutal and largely motivated by anger, a need for power, or sadistic intent. Further, the gratuitous violence involved in the offences and clinical evidence of psychotic features, suggest more severe psychopathological processes in men who sexually assault older women than in those who assault younger victims. Implications for theory and clinical practice are discussed. 相似文献
15.
16.
Detecting pediatric autoimmune neuropsychiatric disorders associated with streptococcus in children with obsessive-compulsive disorder and tics. 总被引:6,自引:0,他引:6
Tanya K Murphy Muhammad Sajid Ohel Soto Nathan Shapira Paula Edge Mark Yang Mark H Lewis Wayne K Goodman 《Neuropsychopharmacology》2004,55(1):61-68
BACKGROUND: A subgroup of children with obsessive-compulsive and tic disorders are proposed to have an infectious trigger. The purpose of this study was to investigate the relationship between group A streptococcal titers and symptom fluctuations in children with a clinical course resembling that described for pediatric autoimmune neuropsychiatric disorders associated with streptococcus. METHODS: Twenty-five children with obsessive-compulsive disorder and/or tic disorder were evaluated for neuropsychiatric severity and group A streptococcal antibody titers (streptolysin O, deoxyribonuclease B, and carbohydrate A) at 6-week intervals for > or = six consecutive evaluations (total visits=277). RESULTS: Children with large symptom fluctuations (n=15) were compared with children without dramatic fluctuations (n=10). Co-movements of obsessive-compulsive/tic severity and group A streptococcal antibodies were assessed. In subjects with large symptom changes, positive correlations were found between streptococcal titers and obsessive-compulsive severity rating changes (p=.0130). These subjects were also more likely to have elevated group A streptococcal titers during the majority of observations (p=.001). Tic symptom exacerbations occurred more often in the fall/winter months than spring/summer months (p=.03). CONCLUSIONS: Patients with marked obsessive-compulsive/tic symptom changes may be characterized by streptococcal titer elevations and exhibit evidence of seasonal tic exacerbations. 相似文献
17.
A controlled, double-masked, randomized study was conducted on ten subjects to determine the effect of fenestration size on the initial comfort of hydrogel contact lenses. Four fenestrated lenses were tested, each lens containing four mid-peripheral fenestrations of the same size. The diameter of the fenestrations used in the four lenses ranged from 0.39 to 0.96 mm. An unfenestrated lens was also tested. All lenses were made of HEMA and were ordered with the following specifications: -3.00 D, 14.0 mm diameter, 8.4 mm back central optic radius and 0.06 mm centre thickness. There was a significant negative correlation between comfort and fenestration size, indicating that larger fenestrations are less comfortable. Even the lens with the smallest fenestrations (0.39 mm) was significantly less comfortable than the unfenestrated lens. The implication of this finding is that fenestrations may not be clinically efficacious in view of the poor comfort (and presumably increased mechanical effect of the fenestration edges on the tarsal conjunctiva) of fenestrated lenses. 相似文献
18.
19.
Nathan J Koewler Katie T Freeman Ryan J Buus Monica B Herrera Juan M Jimenez-Andrade Joseph R Ghilardi Christopher M Peters Lucy J Sullivan Michael A Kuskowski Jack L Lewis Patrick W Mantyh 《Journal of bone and mineral research》2007,22(11):1732-1742
A closed femur fracture pain model was developed in the C57BL/6J mouse. One day after fracture, a monoclonal antibody raised against nerve growth factor (anti-NGF) was delivered intraperitoneally and resulted in a reduction in fracture pain-related behaviors of approximately 50%. Anti-NGF therapy did not interfere with bone healing as assessed by mechanical testing and histomorphometric analysis. INTRODUCTION: Current therapies to treat skeletal fracture pain are limited. This is because of the side effect profile of available analgesics and the scarcity of animal models that can be used to understand the mechanisms that drive this pain. Whereas previous studies have shown that mineralized bone, marrow, and periosteum are innervated by sensory and sympathetic fibers, it is not understood how skeletal pain is generated and maintained even in common conditions such as osteoarthritis, low back pain, or fracture. MATERIALS AND METHODS: In this study, we characterized the pain-related behaviors after a closed femur fracture in the C57BL/6J mouse. Additionally, we assessed the effect of a monoclonal antibody that binds to and sequesters nerve growth factor (anti-NGF) on pain-related behaviors and bone healing (mechanical properties and histomorphometric analysis) after fracture. RESULTS: Administration of anti-NGF therapy (10 mg/kg, days 1, 6, and 11 after fracture) resulted in a reduction of fracture pain-related behaviors of approximately 50%. Attenuation of fracture pain was evident as early as 24 h after the initial dosing and remained efficacious throughout the course of fracture pain. Anti-NGF therapy did not modify biomechanical properties of the femur or histomorphometric indices of bone healing. CONCLUSIONS: These findings suggest that therapies that target NGF or its cognate receptor(s) may be effective in attenuating nonmalignant fracture pain without interfering with bone healing. 相似文献
20.
Sanjeev Kakar Thomas A Einhorn Siddharth Vora Lincoln J Miara Gregory Hon Nathan A Wigner Daniel Toben Kimberly A Jacobsen Maisa O Al-Sebaei Michael Song Philip C Trackman Elise F Morgan Louis C Gerstenfeld George L Barnes 《Journal of bone and mineral research》2007,22(12):1903-1912
Studies have shown that systemic PTH treatment enhanced the rate of bone repair in rodent models. However, the mechanisms through which PTH affects bone repair have not been elucidated. In these studies we show that PTH primarily enhanced the earliest stages of endochondral bone repair by increasing chondrocyte recruitment and rate of differentiation. In coordination with these cellular events, we observed an increased level of canonical Wnt-signaling in PTH-treated bones at multiple time-points across the time-course of fracture repair, supporting the conclusion that PTH responses are at least in part mediated through Wnt signaling. INTRODUCTION: Since FDA approval of PTH [PTH(1-34); Forteo] as a treatment for osteoporosis, there has been interest in its use in other musculoskeletal conditions. Fracture repair is one area in which PTH may have a significant clinical impact. Multiple animal studies have shown that systemic PTH treatment of healing fractures increased both callus volume and return of mechanical competence in models of fracture healing. Whereas the potential for PTH has been established, the mechanism(s) by which PTH produces these effects remain elusive. MATERIALS AND METHODS: Closed femoral fractures were generated in 8-wk-old male C57Bl/6 mice followed by daily systemic injections of either saline (control) or 30 microg/kg PTH(1-34) for 14 days after fracture. Bones were harvested at days 2, 3, 5, 7, 10, 14, 21, and 28 after fracture and analyzed at the tissue level by radiography and histomorphometry and at the molecular and biochemical levels level by RNase protection assay (RPA), real-time PCR, and Western blot analysis. RESULTS: Quantitative muCT analysis showed that PTH treatment induced a larger callus cross-sectional area, length, and total volume compared with controls. Molecular analysis of the expression of extracellular matrix genes associated with chondrogenesis and osteogenesis showed that PTH treated fractures displayed a 3-fold greater increase in chondrogenesis relative to osteogenesis over the course of the repair process. In addition, chondrocyte hypertrophy occurred earlier in the PTH-treated callus tissues. Analysis of the expression of potential mediators of PTH actions showed that PTH treatment significantly induced the expression of Wnts 4, 5a, 5b, and 10b and increased levels of unphosphorylated, nuclear localized beta-catenin protein, a central feature of canonical Wnt signaling. CONCLUSIONS: These results showed that the PTH-mediated enhancement of fracture repair is primarily associated with an amplification of chondrocyte recruitment and maturation in the early fracture callus. Associated with these cellular effects, we observed an increase in canonical Wnt signaling supporting the conclusion that PTH effects on bone repair are mediated at least in part through the activation of Wnt-signaling pathways. 相似文献