全文获取类型
收费全文 | 19337篇 |
免费 | 1561篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 164篇 |
儿科学 | 627篇 |
妇产科学 | 534篇 |
基础医学 | 2929篇 |
口腔科学 | 287篇 |
临床医学 | 2212篇 |
内科学 | 3837篇 |
皮肤病学 | 591篇 |
神经病学 | 1943篇 |
特种医学 | 487篇 |
外科学 | 1865篇 |
综合类 | 159篇 |
一般理论 | 20篇 |
预防医学 | 2180篇 |
眼科学 | 345篇 |
药学 | 1183篇 |
中国医学 | 36篇 |
肿瘤学 | 1570篇 |
出版年
2024年 | 41篇 |
2023年 | 281篇 |
2022年 | 507篇 |
2021年 | 963篇 |
2020年 | 588篇 |
2019年 | 764篇 |
2018年 | 826篇 |
2017年 | 624篇 |
2016年 | 707篇 |
2015年 | 720篇 |
2014年 | 882篇 |
2013年 | 1134篇 |
2012年 | 1645篇 |
2011年 | 1680篇 |
2010年 | 847篇 |
2009年 | 742篇 |
2008年 | 1151篇 |
2007年 | 1163篇 |
2006年 | 996篇 |
2005年 | 964篇 |
2004年 | 881篇 |
2003年 | 785篇 |
2002年 | 674篇 |
2001年 | 109篇 |
2000年 | 84篇 |
1999年 | 103篇 |
1998年 | 132篇 |
1997年 | 110篇 |
1996年 | 76篇 |
1995年 | 83篇 |
1994年 | 67篇 |
1993年 | 48篇 |
1992年 | 47篇 |
1991年 | 52篇 |
1990年 | 47篇 |
1989年 | 26篇 |
1988年 | 25篇 |
1987年 | 29篇 |
1986年 | 26篇 |
1985年 | 34篇 |
1984年 | 30篇 |
1983年 | 26篇 |
1982年 | 20篇 |
1981年 | 30篇 |
1980年 | 21篇 |
1979年 | 12篇 |
1978年 | 24篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Maura Jones Moyle Susan Ellis Weismer Julia L Evans Mary J Lindstrom 《J. Speech Lang. Hear. Res.》2007,50(2):508-528
PURPOSE: This study examined the longitudinal relationships between lexical and grammatical development in typically developing (TD) and late-talking children for the purposes of testing the single-mechanism account of language acquisition and comparing the developmental trajectories of lexical and grammatical development in late-talking and TD children. METHOD: Participants included 30 children identified as late talkers (LTs) at 2;0 (years;months), and 30 TD children matched on age, nonverbal cognition, socioeconomic status, and gender. Data were collected at 5 points between 2;0 and 5;6. RESULTS: Cross-lagged correlational analyses indicated that TD children showed evidence of bidirectional bootstrapping between lexical and grammatical development between 2;0 and 3;6. Compared with the TD group, LTs exhibited less evidence of syntactic bootstrapping. Linear mixed-effects modeling of language sample data suggested that the relationship between lexical and grammatical growth was similar for the 2 groups. CONCLUSION: Lexical and grammatical development were strongly related in both groups, consistent with the single-mechanism account of language acquisition. The results were mixed in terms of finding longitudinal differences in lexical-grammatical relationships between the TD and late-talking children; however, several analyses suggested that for late-talking children, syntactic growth may be less facilitative of lexical development. 相似文献
52.
53.
Julia Yu-Fong Chang Jeng-Tzung Wang Yi-Ping Wang Bu-Yuan Liu Andy Sun Chun-Pin Chiang 《台湾医志》2003,102(12):876-882
BACKGROUND AND PURPOSE: Odontoma is the most common odontogenic tumor. It includes 2 types, the compound and complex odontomas. There has not been a series study of the clinical and histologic features of odontomas from Taiwan. This study evaluated the clinicopathologic features of odontoma in Taiwanese. METHODS: Cases of odontoma treated from 1998 to 2002 identified from medical records were included. The microscopic features, radiographic features, and clinical history of the patients were reviewed and analyzed. RESULTS: A total of 81 odontomas in 81 patients (36 males and 45 females) were included. There were 62 compound and 19 complex odontomas. The mean age of the patients was 18 years with the majority of odontomas occurring in the first (32%) and second decade (38%) of life. Odontomas had a marked predilection for the maxilla (70%) and for the anterior region of the jaw (83%), particularly for the anterior maxilla (62%). Sixty four (79%) of the 81 odontomas were associated with 80 impacted teeth, including 71 permanent teeth, 2 deciduous teeth, and 7 supernumerary teeth. Of the 71 impacted permanent teeth, the maxillary central incisor (27%) was most commonly affected, followed by the maxillary canine (26%) and mandibular canine (24%). Histologic examination revealed enamel matrix in 90%, dentin in 100%, cementum in 88%, pulp tissue in 96%, fibrous capsule in 93%, ghost cells in 83%, reduced enamel epithelium in 86%, and nests of odontogenic epithelium in 58% of odontomas. Dentigerous cyst was associated with 9% of odontomas. CONCLUSIONS: In this series, odontomas occurred most often in the first and second decade of life. Although complex odontomas are usually found in the posterior jaw, in this Taiwanese series they were most commonly found in the anterior maxilla. Odontoma is frequently associated with an impacted tooth and occasionally with a dentigerous cyst. No recurrence of odontomas was found after surgical excision with follow-up of 1 to 15 years. 相似文献
54.
The return of function following transection of the rat sciatic nerve has been assessed after repair by either standard microsurgical techniques (i.e., the use of microsutures to coapt the severed ends) or the new repair technique introduced by de Medinaceli and coworkers. The regeneration after transection was compared with that following sciatic nerve crush, i.e., a lesion in which the return of function is near optimal. Return of function was monitored serially using walking track analysis (i.e., the sciatic functional index, which indicates overall functional performance), the ability to spread the toes (which indicates intrinsic function in the foot), and the determination of muscle twitch tension of the middle digit. Function in the nerve crush group returned to within the normal range by 53 days, but function in the transection and repair groups did not return to normal before the rats were perfused at 85 postoperative days. However, the function regained when nerves were repaired with the de Medinaceli technique was significantly superior to that regained after repair with microsutures. Histological examination of the repair site (at 85 days) revealed that the regenerated nerve fibers in the de Medinaceli group crossed the site of anastomosis in a relatively orderly fashion, whereas they were more randomly arranged when microsutures were used. However, there was no statistical difference between the two groups in the number of regenerated fibers present in the distal stump. The increase in function in the de Medinaceli group may therefore arise primarily from an increase in the proportion of regenerating fibers which reach appropriate targets.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
55.
56.
Hepatic encephalopathy is ameliorated by drugs acting on the central GABAA-benzodiazepine receptor complex. To investigate whether these effects are specific for hepatic encephalopathy or just reflect a nonspecific arousal reaction, various benzodiazepine antagonists like flumazenil or with inverse agonistic properties (Ro 15-4513, Ro 15-3505) were studied in uremic encephalopathy in rats after bilateral ureteral ligation (n = 20) and compared with hepatic encephalopathy caused by thioacetamide-induced acute liver failure (n = 33). As soon as the animals developed clear signs of metabolic encephalopathy, their motor activity was recorded in an animal activity meter for 10 min. Furthermore, a composite score was calculated by grading various behavioral signs from 0 = absent to 3 = apparently normal. Rats were then injected with coded preparations of Ro 15-4513 (0.5, 2.5 and 5 mg/kg body wt intraperitoneally), flumazenil (2.5, 10, 25 and 40 mg/kg), Ro 15-3505 (10 mg/kg) or vehicle, and the measurements were repeated. The code was broken after the completion of the study. Pretreatment motor activity was decreased both in hepatic and uremic encephalopathy (20.7 +/- 6.4 [S.E.M.] and 41.3 +/- 37.1 movements/10 min). In hepatic encephalopathy motor activity and the composite score were improved both by 5 mg/kg Ro 15-4513 (by 293%, p less than 0.05) and by 10 mg/kg Ro 15-3505 (by 509%, p greater than 0.01), whereas vehicle and flumazenil had no effects. In uremic encephalopathy neither drug was effective in improving the neurobehavioral status.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
57.
Manic episode with psychotic symptoms induced by subthalamic nucleus stimulation in a patient with Parkinson's disease. 总被引:5,自引:0,他引:5
Jan Herzog Julia Reiff Paul Krack Karsten Witt Bettina Schrader Dieter Müller Günther Deuschl 《Movement disorders》2003,18(11):1382-1384
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy for Parkinson's disease (PD). A manic episode with psychotic symptoms induced by STN-DBS occurred in a previously psychiatrically healthy patient, focusing on the role of STN-DBS in influencing not only motor but also emotional behaviour. 相似文献
58.
Julia Valderrama Fernando Zacarías Rafael Mazin 《Pan American journal of public health》2004,16(3):211-217
From the data submitted to the Pan American Health Organization (PAHO) by nationwide programs against sexually transmitted diseases (STD), HIV infection, and AIDS (2002), one can estimate the overall prevalence of syphilis among pregnant women to be 3.1% and to range from 1.00% in Peru to 6.21% in Paraguay. According to these data, the incidence of congenital syphilis ranges from 1.4 per 1000 live births in El Salvador to 12.0 per 1000 live births in Honduras. Among men who engage in sex with other men, who often classify themselves as heterosexual, as well as in female sex workers, the prevalence of syphilis ranged from 5% to 15%. Factors that determine the persistence of congenital syphilis as public health problem include a lack of awareness of the seriousness of the problem among politicians, health officials, and health care providers, difficult access to prenatal care, and screening services, a low demand for the test among users, and the stigma and discrimination that surround sexually transmitted diseases (STD). This paper seeks to focus the attention of health professionals on maternal and congenital syphilis so they will undertake actions, using an interprogrammatic approach, to eliminate congenital syphilis from Latin America and the Caribbean. Eliminating congenital syphilis will only become possible if interventions targeting vulnerable groups are also implemented. PAHO's role in eliminating congenital syphilis includes determining the baseline situation in the Region as a whole and in each country, developing communication and procurement strategies, supporting nationwide programs, promoting operational research, and facilitating interprogrammatic coordination. 相似文献
59.
Michael Burwinkel Constanze Riemer Anja Schwarz Julia Schultz Sabine Neidhold Theresa Bamme Michael Baier 《International journal of developmental neuroscience》2004,22(7):497-505
Prion infections of the central nervous system (CNS) are characterised by a reactive gliosis and the subsequent degeneration of neuronal tissue. The activation of glial cells, which precedes neuronal death, is likely to be initially caused by the deposition of misfolded, proteinase K-resistant, isoforms (termed PrP(res)) of the prion protein (PrP) in the brain. Cytokines and chemokines released by PrP(res)-activated glia cells may contribute directly or indirectly to the disease development by enhancement and generalisation of the gliosis and via cytotoxicity for neurons. However, the actual role of prion-induced glia activation and subsequent cytokine/chemokine secretion in disease development is still far from clear. In the present work, we review our present knowledge concerning the functional biology of cytokines and chemokines in prion infections of the CNS. 相似文献
60.
Marjolein Gysels Rhidian Hughes Fiona Aspinal Julia M Addington-Hall Irene J Higginson 《International journal for quality in health care》2004,16(5):375-381
OBJECTIVE: To investigate the opinions of stakeholders (service commissioners and providers) on how performance data should be presented, in order to develop effective feedback methods to facilitate the use of these data in decision making. DESIGN: A qualitative analysis of semi-structured face-to-face and telephone interviews. League tables and fictional box plots were presented as an illustrative guide. The themes covered in the interviews were the effectiveness of these two feedback formats, their positive and negative characteristics, and ideas for new and improved feedback mechanisms. PARTICIPANTS: Thirty-six stakeholders representing a range of clinical and non-clinical roles within palliative care and the wider health care system across a variety of statutory and non-statutory organizations from London and the West Midlands. RESULTS: Box plots were received more positively than league tables, and qualitative information was considered more appropriate than pictorial feedback. Conventional methods such as league tables and box plots were judged to lack essential information on which important decisions could be based, such as additional contextual information and the methodological assumptions of the instrument. Both feedback methods were considered useful as an impetus to further discussion. There was a consensus that feedback should be constructive and able to be adapted to the organizational realities in which UK health services function. CONCLUSION: Qualitative research was viewed as the right evidence for gaining an understanding of the quality of end of life care. Stakeholders highlighted the importance of the lay perspective, which requires approaches that illuminate the subjective meanings of patient experience. 相似文献