全文获取类型
收费全文 | 800篇 |
免费 | 45篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 36篇 |
妇产科学 | 10篇 |
基础医学 | 109篇 |
口腔科学 | 16篇 |
临床医学 | 110篇 |
内科学 | 130篇 |
皮肤病学 | 40篇 |
神经病学 | 71篇 |
特种医学 | 125篇 |
外科学 | 61篇 |
综合类 | 30篇 |
一般理论 | 1篇 |
预防医学 | 50篇 |
眼科学 | 4篇 |
药学 | 23篇 |
1篇 | |
肿瘤学 | 28篇 |
出版年
2022年 | 5篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 12篇 |
2017年 | 4篇 |
2016年 | 14篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 27篇 |
2012年 | 18篇 |
2011年 | 19篇 |
2010年 | 28篇 |
2009年 | 31篇 |
2008年 | 20篇 |
2007年 | 34篇 |
2006年 | 25篇 |
2005年 | 24篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 25篇 |
2001年 | 17篇 |
2000年 | 11篇 |
1999年 | 20篇 |
1998年 | 41篇 |
1997年 | 48篇 |
1996年 | 40篇 |
1995年 | 20篇 |
1994年 | 29篇 |
1993年 | 23篇 |
1992年 | 14篇 |
1991年 | 16篇 |
1990年 | 15篇 |
1989年 | 32篇 |
1988年 | 23篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 15篇 |
1983年 | 20篇 |
1982年 | 15篇 |
1981年 | 16篇 |
1980年 | 11篇 |
1979年 | 3篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1970年 | 2篇 |
1969年 | 5篇 |
排序方式: 共有850条查询结果,搜索用时 15 毫秒
1.
D Monnier† C Vidal‡ L Martin§ A Danzon¶ F Pelletier† E Puzenat† MP Algros†† D Blanc† R Laurent† PH Humbert† F Aubin† 《Journal of the European Academy of Dermatology and Venereology》2006,20(10):1237-1242
BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumour of the skin, with an estimated incidence of 0.8 to five cases per 1 million people per year. OBJECTIVE: To study epidemiological, immunohistochemical and clinical features, delay in diagnosis, type of treatment and outcome of DFSP from 1982 to 2002. METHODS: Using data from the population-based cancer registry, 66 patients with pathologically proved DFSP were included (fibrosarcomatous DFSP were excluded). Each patient lived in one of the four departments of Franche-Comté (overall population of 1 million people) at the time of diagnosis. The main data sources came from public and private pathology laboratories and medical records. The rules of the International Agency for Research on Cancer were applied. RESULTS: The estimated incidence of DFSP in Franche-Comté was about three new cases per 1 million people per year. Male patients were affected 1.2 times as often as female patients were. The trunk (45%) followed by the proximal extremities (38%) were the most frequent locations. DFSP occurred mainly in young adults between 20 and 39 years of age. Mean age at diagnosis was 43 years, and the mean delay in diagnosis was 10.08 years. Our 66 patients initially underwent a radical local excision. Among them, 27% experienced one or more local recurrences during 9.6 years of follow-up. There was one regional lymph node recurrence without visceral metastases. These recurrences were significantly related to the initial peripheral resection margins. We observed a local recurrence rate of 47% for margins less than 3 cm, vs. only 7% for margins ranging from 3 to 5 cm [P=0.004; OR=0.229 (95%, CI=0.103-0.510)]. The mean time to a first local recurrence was 2.65 years. Nevertheless, there was no death due to the DFSP course at the end of the follow-up, and the final outcome was favourable. CONCLUSION: Our study emphasizes the importance of wide local excision with margins of at least 3 cm in order to prevent local recurrence. However, the recent development of inhibitors of signal transduction by the PDGFB pathway should soon modify the surgical strategy, which is often too mutilating. 相似文献
2.
W W Campbell M M Polansky N A Bryden J H Soares R A Anderson 《The Journal of nutrition》1989,119(4):653-660
The effects of exercise training and dietary chromium intake on rat liver and muscle glycogen metabolism, tissue and body weight and feed consumption were examined. After 16 wk of training, liver, gastrocnemius and biceps femoris glycogen concentrations were higher in the trained compared to sedentary groups, independent of dietary chromium. There was a chromium x training interaction on glycogen synthase activities in the liver and gastrocnemius muscle. Liver glycogen phosphorylase activities (expressed per g liver) were lower in the chromium-supplemented rats as compared to the non-supplemented rats after 5 wk of dietary treatment, but were similar after 8 wk and higher after 18 wk. Gastrocnemius phosphorylase activity (expressed per mg protein) was lower in the trained rats as compared to the sedentary rats after 16 wk, independent of dietary chromium. Biceps femoris phosphorylase activities were not altered due to training or dietary chromium. Total protein concentration increased in the liver but decreased in the gastrocnemius due to dietary chromium. In summary, liver glycogen synthase and phosphorylase activities were dependent upon dietary chromium. Dietary chromium altered gastrocnemius synthase, but not phosphorylase activities. Changes in enzyme activities may be related to the chromium-dependent effects on liver protein and the chromium and training-dependent effects on gastrocnemius total protein. 相似文献
3.
R Zachariah AD Harries MP Spielmann V Arendt D Nchingula R Mwenda O Courtielle P Kirpach B Mwale FML Salaniponi 《Malawi medical journal : the journal of Medical Association of Malawi》2002,14(2):10-12
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E.coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (p<0.01). Resistance was 89% among HIV-infected TB patients (receiving co-trimoxazole), while in HIV negative patients (receiving anti-TB therapy alone) it was 62% (p<0.001). The study shows a significant increase of E.coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E.coli and the Salmonella species, these findings could herald limitations on the short and long term benefits to be anticipated from the use of co-trimoxazole prophylaxis in preventing non-typhoidal salmonella bacteraemia and enteritis in HIV infected TB patients in Malawi. 相似文献
4.
BACKGROUND: Partnerships have been investigated in different professions,but other than identifying problems, little work has been carriedout on general practice. OBJECTIVE: The aim of this present study was to develop methods for studyingpartnerships in general practice. METHOD: A tripartite methodological approach was used, with questionnairesadapted from other instruments in use in other professions,followed by an individual interview with each partner, and non-participantobservation at a partnership meeting. Results for one case-studypartnership are given. RESULTS: There were no major differences between the partners on alldimensions measured; the minor differences indicated by theresults of the questionnaires were corroborated by the partnerinterviews and observations. CONCLUSIONS: We conclude that the use of such techniques could provide supportto partnerships going through significant periods of change. Keywords. General practice, interview, observation, partnerships, questionnaire. 相似文献
5.
6.
Flagella as a potential marker for Campylobacter jejuni strains associated with Guillain-Barré syndrome 总被引:2,自引:0,他引:2
Campylobacter jejuni recovered from patients with Guillain-Barré syndrome (GBS) in different geographical locations and bearing different heat-labile and heat-stable antigens were found to have identical amino acid sequences in their flagellar flaA short variable region, suggesting that it may be a potentially useful marker for GBS association. 相似文献
7.
Recessively inherited L-DOPA-responsive parkinsonism in infancy caused by a point mutation (L205P) in the tyrosine hydroxylase gene 总被引:4,自引:0,他引:4
8.
9.
OBJECTIVES: To study the efficacy of otoacoustic emissions (OAEs) as a screening test for hearing impairment in children with acute bacterial meningitis. Hearing tests were performed before discharge from the hospital in an attempt to improve coverage and avoid delays in the diagnosis of postmeningitic hearing loss. METHODS: Children with bacterial meningitis were recruited from 21 centers. In the 48 hours before discharge from the hospital, all patients underwent a thorough audiologic assessment consisting of transient evoked OAEs, auditory brainstem responses (ABRs), otoscopy, and tympanometry. Hearing loss was defined as ABR threshold >/=30 dB. The results of OAE screening were compared with the gold standard of ABR threshold. RESULTS: Of 124 children recruited, we were able to perform both OAEs and ABRs on 110 children. Seven (6.3%) of the 110 children had ABR threshold >/=30 dB; 2 had sensorineural hearing loss and 5 had conductive hearing loss. At follow-up, hearing loss persisted in both cases of sensorineural hearing loss and no new cases were identified. All 7 children with hearing loss failed the OAE screening test. Ninety-four children with normal hearing thresholds passed the test, and 9 failed. Thus, the screening test had a sensitivity of 1.00 (95% confidence interval, 0.59 to 1.00), a specificity of 0.91 (0.85 to 0.97), a positive predictive value of 0. 44 (0.20 to 0.70), and a negative predictive value of 1.00 (0.96 to 1.00). CONCLUSIONS: OAE screening in children recovering from meningitis was found to be feasible and effective. The test was highly sensitive and reasonably specific. Inpatient OAE screening should allow early diagnosis of postmeningitic hearing loss and prompt auditory rehabilitation. 相似文献
10.
Iron-overload diseases frequently develop hepatocellular carcinoma. The
genotoxic mechanism whereby iron is involved in hepatocarcinogenesis might
involve an oxidative process via the intermediate production of reactive
oxygen species. This was presently investigated by examining kinetics of
formation and repair of DNA base lesions in primary rat hepatocyte cultures
supplemented with the iron chelate, ferric nitrilotriacetate Fe-NTA (10 and
100 microM). Seven DNA base oxidation products have been identified in DNA
extracts by gas chromatography- mass spectrometry, which showed a
predominance of oxidized-purines (8- oxo-guanine, xanthine, fapy-adenine,
2-oxo-adenine) above oxidized pyrimidines (5-OHMe-uracil, 5-OH-uracil,
5-OH-cytosine) in control cultures. All these DNA oxidation products
revealed a significant dose- dependent increase at 4 to 48 h after Fe-NTA
supplementation, among which fapy-adenine showed the highest increase and
5-OH-cytosine was the least prominent. Involvement of iron in this
oxidative process was established by a correlation between extent in DNA
oxidation and intracellular level of toxic low molecular weight iron. DNA
excision- repair activity was estimated by release of DNA oxidation
products in culture medium. All the seven DNA oxidation products were
detected in the medium of control cultures and showed basal repair
activity. This DNA repair activity was increased in a time- and
dose-dependent fashion with Fe-NTA. Oxidized-pyrimidines, among which was
5-OHMe-Uracil, were preferentially repaired, which explains the low levels
detected in oxidized DNA. Since oxidized bases substantially differed from
one another in terms of excision rates from cellular DNA, specific
excision- repair enzymes might be involved. Our findings, however,
demonstrate that even though DNA repair pathways were activated in
iron-loaded hepatocyte cultures, these processes were not stimulated enough
to prevent an accumulation of highly mutagenic DNA oxidative products in
genomic DNA. The resulting genotoxic effect of Fe-NTA might be relevant in
understanding the hepatocarcinogenic evolution of iron-overload diseases.
相似文献