全文获取类型
收费全文 | 45020篇 |
免费 | 2714篇 |
国内免费 | 258篇 |
专业分类
耳鼻咽喉 | 388篇 |
儿科学 | 1294篇 |
妇产科学 | 1202篇 |
基础医学 | 5915篇 |
口腔科学 | 938篇 |
临床医学 | 4505篇 |
内科学 | 9834篇 |
皮肤病学 | 880篇 |
神经病学 | 4794篇 |
特种医学 | 1498篇 |
外科学 | 5913篇 |
综合类 | 175篇 |
一般理论 | 19篇 |
预防医学 | 3350篇 |
眼科学 | 767篇 |
药学 | 2774篇 |
1篇 | |
中国医学 | 85篇 |
肿瘤学 | 3660篇 |
出版年
2024年 | 70篇 |
2023年 | 520篇 |
2022年 | 998篇 |
2021年 | 1802篇 |
2020年 | 1056篇 |
2019年 | 1484篇 |
2018年 | 1699篇 |
2017年 | 1190篇 |
2016年 | 1337篇 |
2015年 | 1542篇 |
2014年 | 2120篇 |
2013年 | 2640篇 |
2012年 | 3913篇 |
2011年 | 3902篇 |
2010年 | 1972篇 |
2009年 | 1842篇 |
2008年 | 3110篇 |
2007年 | 2999篇 |
2006年 | 2702篇 |
2005年 | 2674篇 |
2004年 | 2231篇 |
2003年 | 1995篇 |
2002年 | 1767篇 |
2001年 | 227篇 |
2000年 | 161篇 |
1999年 | 234篇 |
1998年 | 303篇 |
1997年 | 222篇 |
1996年 | 198篇 |
1995年 | 181篇 |
1994年 | 154篇 |
1993年 | 122篇 |
1992年 | 88篇 |
1991年 | 76篇 |
1990年 | 63篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 35篇 |
1986年 | 31篇 |
1985年 | 31篇 |
1984年 | 38篇 |
1983年 | 19篇 |
1982年 | 39篇 |
1981年 | 24篇 |
1980年 | 21篇 |
1979年 | 9篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 8篇 |
1972年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Giovanni Battista Grossi Carlo Maiorana Rocco Alberto Garramone Andrea Borgonovo Luca Creminelli Franco Santoro 《Journal of oral and maxillofacial surgery》2007,65(5):901-917
PURPOSE: The purpose of this study was to identify the risk factors for severe discomfort after mandibular third molar surgery and to assess the validity of the Postoperative Symptom Severity (PoSSe) scale. PATIENTS AND METHODS: In a 2-year prospective study, a total of 255 unilateral impacted mandibular third molar teeth were surgically removed under local anesthesia by 3 surgeons. Standardized surgical and analgesic protocols were followed. At the review appointment, 1 week after surgery, all patients returned a completed follow-up questionnaire (PoSSe scale) and were evaluated clinically for postoperative pain (number of painkillers taken) and trismus (differences in mouth opening). Sixteen predictive variables were evaluated using stepwise logistic regression analysis to identify the risk factors associated with severe discomfort. RESULTS: Severe postoperative discomfort was predicted by these independent variables: gender, tobacco use, ramus relationship/space available, and antibiotic prophylaxis. Oral contraceptive use and operation time were not identified as risk factors. The patients' perceptions of the severity of symptoms (PoSSe scale score) was strongly correlated with clinical assessment of trismus (r = 0.54) and pain (r = 0.42). CONCLUSION: The PoSSe scale resulted in a valid and responsive measure of the severity of symptoms after surgical extraction of lower third molars and reflected the clinical severity of the postoperative discomfort. From a patient's perspective, operative factors had little bearing on the quality of life after removal of mandibular third molars. 相似文献
52.
Paola Sarchielli Andrea Alberti Beatrice Gallai Francesca Coppola Antonio Baldi Ardesio Floridi Virgilio Gallai 《The journal of headache and pain》2002,3(3):129-135
Little has been done to investigate the biochemical basis of chronic daily headache (CDH). Our group has recently demonstrated
an increase in the cerebrospinal fluid (CSF) levels of nerve growth factor (NGF) in CDH patients, supporting the involvement
of this growth factor in the abnormal processing of head pain in this pathological condition. Other members of the neurotrophin
family, especially brain-derived neurotrophic factor (BDNF), have been hypothesized as being involved in the development of
chronic head pain in patients affected by CDH, but so far no data are available on this subject. BDNF, NGF and glutamate levels
were determined in the CSF of 25 patients affected by CDH with a previous history of migraine. These levels were compared
with those of a group of 20 control subjects, for whom the CSF examination and other instrumental investigations excluded
diseases of the central and peripheral nervous systems. Significantly higher levels of BDNF, NGF and glutamate were found
in CDH patients compared with control subjects (p<0.0001, p<0.0002 and p<0.001, respectively). A significant positive correlation emerged between CSF values of BDNF and those of NGF (r=0.61, p<0.001) and glutamate (r=0.44, p<0.025) in CDH patients. No significant differences were detected in BDNF, NGF and glutamate levels between CDH patients with
analgesic overuse and those without. These results support the involvement of BDNF in CDH through the potentiation of glutamatergic
transmission involved in the processing of head pain. The significant correlation between BDNF and NGF levels suggests that
NGF-mediated up-regulation of BDNF in central sites involved in long-term sensitization plays a key role in persistent head
pain in CDH patients.
Correspondence to P. Sarchielli 相似文献
53.
54.
55.
BACKGROUND: Worldwide, fire-related burns are a major cause of unintentional injury, morbidity and mortality, with the majority of deaths occurring in developing countries. In the US, as in other countries, most fatal fires occur in the home. Effective prevention strategies for residential fires are, however, currently underutilized. The news media is one available communication channel to promote such strategies, and analyzing current news coverage is a first step towards incorporating media advocacy into injury prevention efforts related to residential fires. METHODS: Four daily newspapers circulating widely in Maryland were monitored for 1 year. Articles describing residential fires were coded for measures of prominence, content and frame. Analysis focused on measures of issue newsworthiness, reporting of causation and consequences of fires, and inclusion of public health context and conveyance of prevention messages. RESULTS: The data indicate that fires are newsworthy, with 374 relevant news articles in a 1-year period, 32% of which appear on the first page of a section. Coverage generally concerned recent local fire events. Most articles discussed the consequences of fires (88%), and identified a causal factor (58%). Only 36%, however, included prevention information, and less than one-quarter set residential fires in a public health context. CONCLUSION: The newsworthiness of residential fires provides a clear opportunity for widespread communication around injury prevention. Improving media advocacy will entail framing discussion of recent fire events in such a way as to support inclusion of prevention strategies and a public health context in news coverage. 相似文献
56.
Antonio Fea Andrea Grosso Marilena Rabbione Federico Grignolo 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2007,245(2):315-317
Background Optic disc anomalies are frequently associated with Alagille syndrome. We report here the first case of a patient with Alagille
syndrome combined with optic pit and serous macular detachment.
Methods A male patient with Alagille syndrome was referred from the pediatric hepatology department for investigation of visual loss
in the right eye. Anterior segment examination showed evidence of posterior embryotoxon, confirmed by gonioscopic evaluation.
Dilated fundus examination revealed serous macular detachment and optic pit.
Results OCT 3 scans confirmed the clinical findings.
Conclusions Optic pit is uncommon and should prompt a search for genetic disorders or development abnormalities. The association between
the two syndromes in this patient might be due to failure of correct neuroectodermal development, for which a common genetic
pathway is likely. 相似文献
57.
Antonella d’Arminio Monforte Paola Cinque Luca Vago Aleandro Rocca Antonella Castagna Cristina Gervasoni Maria Rosa Terreni Roberto Novati Andrea Gori Adriano Lazzarin Mauro Moroni 《Journal of neurology》1996,244(1):35-39
Twenty patients with AIDS who had intracranial lesions underwent both brain biopsy and cerebro-spinal fluid (CSF) examination
to compare histological diagnosis with the polymerase chain reaction (CSF-PCR) for the identification of infectious agents.
CSF-PCR was performed for herpes simplex virus, varicella zoster virus, cytomegalovirus (CMV), JC virus (JCV), Epstein-Barr
virus (EBV), Toxoplasma gondii and Mycobacterium tuberculosis. A definitive diagnosis was obtained by brain biopsy in 14 patients (2 with astrocytoma, 12 with brain infection). CSF-PCR
was positive for EBV DNA in 3 of 3 cases of primary cerebral lymphoma, positive for JCV DNA in 6 of 7 biopsy-proven (and one
autopsy-proven) cases of progressive multifocal leukoencephalopathy (PML). CSF-PCR was positive for CMV DNA in one biopsy-proven
and one autopsy-proven case of CMV encephalitis (the former also had PML) and positive for M. tuberculosis DNA in one case of tuberculous encephalitis. None of the five toxoplasmic encephalitis cases (one definite, four presumptive)
were T. gondii DNA positive. There was close correlation between histology and CSF-PCR for CMV encephalitis, PML and PCL. Antitoxoplasma
therapy affected the sensitivity of both histological and CSF-PCR methods.
Received: 8 November 1995 Received in revised form: 9 July 1996 Accepted: 19 July 1996 相似文献
58.
The spatial and temporal pattern of expression of the protein products of immediate early genes (IEGs) c-fos, fos B, and egr-1 were mapped in medial preoptic area (MPOA) and ventral bed nucleus of stria terminalis (VBST) during maternal behavior in rats. Immunocytochemical analysis indicated significant increases in the number of cells expressing c-Fos after 2 h of pup exposure, while Fos B levels showed a delayed response, reaching maximal levels after 6 h. 相似文献
59.
Giovanni Melioli Editta Baldini Maria Cristina Mingari Andrea De Maria Mario Roberto Sertoli Fausto Badellino Pier Luigi Percivale Alessandra Catturich Sergio Bertoglio Dario Civalleri Leonardo Santi Lorenzo Moretta 《International journal of cancer. Journal international du cancer》1989,43(2):231-234
In the course of a phase I trial, in which recombinant IL-2 (rIL-2) was infused intraperitoneally (i.p.) in patients with peritoneal carcinomatosis, we evaluated the effect on "tumor-associated lymphocytes" (TAL) isolated from the ascitic fluid. No major changes in the percentages of cells expressing the CD3, CD4, CD8, Leu-7, OKM1 and WT-31 antigens were detected either in TAL or in peripheral blood lymphocytes (PBL) after 7 days of rIL-2 infusion. In contrast the percentages of TAL (but not PBL) expressing surface IL-2 receptor (Tac), or LAK-1 antigen were sharply increased. Analysis of cytolytic functions showed a potentiation of the lytic activity against natural-killer (NK) sensitive K562 target cells and the de novo appearance of lytic activity against fresh melanoma cells. In one patient IFN-gamma was detected in the ascitic fluid following rIL-2 infusion. T-cell clones derived from the patient were analyzed for the IFN-gamma production. While only approximately 40% of PB-derived control clones produced medium to low amounts of IFN-gamma, all of the TAL-derived clones produced medium to high amounts of the lymphokine. 相似文献
60.
Napolitano LA Burt TD Bacchetti P Barrón Y French AL Kovacs A Anastos K Young M McCune JM Greenblatt RM 《Journal of acquired immune deficiency syndromes (1999)》2005,40(5):581-584
Sex-based differences in CD4 T-cell (CD4) counts are well recognized, but the basis for these differences has not been identified. Conceivably, homeostatic factors may play a role in this process by regulating T-cell maintenance and repletion. Interleukin (IL)-7 is essential for normal T-cell production and homeostasis. We hypothesized that differences in IL-7 might contribute to sex-based differences in CD4 counts. Circulating IL-7 levels were analyzed in 299 HIV-1-infected women and men. Regression analysis estimated that IL-7 levels were 40% higher in women than in men (P = 0.0032) after controlling for CD4 count, age, and race. Given the important role of IL-7 in T-cell development and homeostasis, these findings suggest that higher IL-7 levels may contribute to higher CD4 counts in women. 相似文献