全文获取类型
收费全文 | 840篇 |
免费 | 72篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 44篇 |
妇产科学 | 47篇 |
基础医学 | 92篇 |
口腔科学 | 19篇 |
临床医学 | 59篇 |
内科学 | 154篇 |
皮肤病学 | 24篇 |
神经病学 | 41篇 |
特种医学 | 11篇 |
外科学 | 62篇 |
综合类 | 52篇 |
预防医学 | 132篇 |
眼科学 | 9篇 |
药学 | 63篇 |
中国医学 | 12篇 |
肿瘤学 | 90篇 |
出版年
2023年 | 7篇 |
2022年 | 29篇 |
2021年 | 27篇 |
2020年 | 16篇 |
2019年 | 33篇 |
2018年 | 28篇 |
2017年 | 22篇 |
2016年 | 26篇 |
2015年 | 27篇 |
2014年 | 45篇 |
2013年 | 34篇 |
2012年 | 55篇 |
2011年 | 64篇 |
2010年 | 25篇 |
2009年 | 32篇 |
2008年 | 52篇 |
2007年 | 36篇 |
2006年 | 44篇 |
2005年 | 51篇 |
2004年 | 32篇 |
2003年 | 40篇 |
2002年 | 30篇 |
2001年 | 21篇 |
2000年 | 27篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1965年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有915条查询结果,搜索用时 16 毫秒
91.
Delay and survival in bladder cancer 总被引:3,自引:0,他引:3
Wallace DM Bryan RT Dunn JA Begum G Bathers S;West Midlands Urological Research Group 《BJU international》2002,89(9):868-878
OBJECTIVE: To assess in detail and evaluate the effect on survival of delays in the diagnosis and treatment of cancer (which might lead to a worse prognosis), dividing the delay from onset of symptoms to first treatment into several components, comprising patient delay, general practitioner (GP) delay, and two or more periods of hospital delay. PATIENTS AND METHODS: Data were prospectively collected on 1537 new cases of urothelial cancer in the West Midlands from 1 January 1991 to 30 June 1992. Death information was obtained from the West Midlands Cancer Intelligence Unit and censored at 31 July 2000. The influence of delay times on survival was explored. RESULTS: The median delay from onset of symptoms to GP referral was 14 days (Delay 1), from GP referral to first hospital attendance was 28 days (Delay 2), and from first hospital attendance to first transurethral resection of bladder tumour was 20 days (Delay 3). The median hospital delay (Delay 2 + 3) was 68 days and the median total delay (Delay 1 + 2 + 3) was 110 days. Patients with a shorter Delay 1 had a lower tumour stage and a 5% better 5-year survival. Patients with a shorter hospital delay had worse survival; total delay had no effect on survival. CONCLUSIONS: There was significantly better survival for patients referred to hospital within 14 days of the onset of symptoms. The relationship between delay and survival in bladder cancer is complex. Hospital delays may be influenced more by comorbidity than by the characteristics of the tumour. However, the adverse effects of delay seem to be most pronounced for patients with pT1 tumours. 相似文献
92.
M. U. Khan M.B.B.S. D.P.H. M. M. Shahidullah M.Sc. T. Begum B.A. 《Indian journal of pediatrics》1983,50(5):493-495
Breast feeding was found to give protection against many gastrointestinal infections in infants. A study has been conducted to examine whether breastfeeding protects children from contracting ascaris lumbricoides and hookworm infections. History of breast feeding and supplementation in urban children from low economic strata were obtained and stools were examined for ova of ascaris and hookworm. There was no significant difference in the presence of hookworm ova between the only breastfed group and the breastfed with supplemented group by two years of age. By the age of six and 24 months the presence of ascaris ova was significantly higher in the breastfed with supplemented group than the breastfed only group. It appears that exclusive breast feeding may have some role in preventing acquisition of ascaris infection in urban slums with poor sanitation facilities. 相似文献
93.
94.
95.
Local production of anti-vibrio cholerae mucosal antibody in reproductive tract tissues after cholera 总被引:4,自引:0,他引:4
Ryan ET Bridges EA Crean TI Gausia K Hamadani JD Aziz A Hawkes S Begum M Bogaerts J Faruque SM Salam MA Fuchs GJ Calderwood SB 《The Journal of infectious diseases》2001,184(5):643-647
To investigate whether intestinal presentation of an antigen by Vibrio cholerae, a noninvasive organism, could induce an anatomically distant mucosal immune response in reproductive tract tissues, the endocervical immune responses of women in Bangladesh were evaluated after cholera. Endocervical secretions were analyzed for secretory IgA (sIgA) antibody against the B subunit of cholera toxin (CtxB) in 9 women with cholera and 8 women with diarrhea caused by neither V. cholerae nor heat labile enterotoxin-producing Escherichia coli. Women infected with V. cholerae developed significant sIgA anti-CtxB responses in endocervical samples (P< or =.02). Antibody subtype analysis of endocervical IgA was consistent with local mucosal production (P< or =.001). Women with cholera did not develop sIgA anti-CtxB responses in serum. The ability to generate specific mucosal immune responses in reproductive tract tissues after intestinal presentation of antigen could facilitate development of vaccines effective against reproductive tract pathogens. 相似文献
96.
Abdul Qayoom Mugheri Aneela Tahira Umair Aftab Muhammad Ishaq Abro Arfana Begum Mallah Gulam Zuhra Memon Humaira Khan Mazhar Ali Abbasi Imran Ali Halepoto Saleem Raza Chaudhry Zafar Hussain Ibupoto 《RSC advances》2019,9(59):34136
The design of efficient nonprecious catalysts for the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is a necessary, but very challenging task to uplift the water-based economy. In this study, we developed a facile approach to produce porous carbon from the dehydration of sucrose and use it for the preparation of nanocomposites with cobalt oxide (Co3O4). The nanocomposites were studied by the powder X-ray diffraction and scanning electron microscopy techniques, and they exhibited the cubic phase of cobalt oxide and porous structure of carbon. The nanocomposites showed significant OER activity in alkaline media, and the current densities of 10 and 20 mA cm−2 could be obtained at 1.49 and 1.51 V versus reversible hydrogen electrode (RHE), respectively. The impedance study confirms favorable OER activity on the surface of the prepared nanocomposites. The nanocomposite is cost-effective and can be capitalized in various energy storage technologies.The design of efficient nonprecious catalysts for the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is a necessary, but very challenging task to uplift the water-based economy. 相似文献
97.
R. Iyyadurai S. Immanuel A. Begum A. Zachariah S. Jasmine 《Clinical toxicology (Philadelphia, Pa.)》2014,52(5):538-541
Background. Organophosphate (OP) poisoning results in significant toxicity while pyrethroid poisoning is associated with extremely low fatality. OPs can inhibit the detoxification of pyrethroid and increase the toxicity of the combination. We assessed whether mixed OP-pyrethroid poisoning impacted outcome in human poisoning. Methods. Patients were identified from a prospectively collected institutional poisoning database that incorporates demographic and outcome data of patients presenting with poisoning. Results. Of the 1177 poisoned patients admitted over 2 years, 32 presented with OP-pyrethroid (50% chlorpyrifos-5% cypermethrin mixture) poisoning (Group 1), 26 consumed 20% chlorpyrifos (Group 2), and 32 took 15% cypermethrin (Group 3). Seizures occurred in 15.6% (n = 5) with chlorpyrifos-cypermethrin poisoning, 18.8% (n = 6) with cypermethrin poisoning, and 3.9% (n = 1) with chlorpyrifos poisoning. Ventilatory requirements were 53.5% (17/32), 42.3% (11/26), and 15.7% (5/32) in Groups 1–3, respectively. Ventilator-free days (Mean ± SD) was significantly lower (p < 0.006) in Group 1 (20.9 ± 9.3 days) than those in Group 2 (26.1 ± 4.4 days) or 3 (27.8 ± 0.6). The median (inter-quartile range) hospital stay was 5.5 (4–19.5), 5 (5–6), and 1 (0.65–1.5) days, respectively, in the three groups. Four patients died in Group 1 (13%). None died in the other groups. Conclusion. Although confounded by the varying quantity of chlorpyrifos and cypermethrin in the different formulations, patients with mixed poisoning appear to have shorter ventilator-free days than patients poisoned by either of the pesticides alone. Further studies are required comparing patients poisoned by formulations with similar quantities of OP and pyrethroid or with analysis of blood pesticide concentration on admission. 相似文献
98.
The prevalence of gestational diabetes mellitus in Bangladesh: a systematic review and meta-analysis
Begum Rahima Roy Sourav Banik Sujan 《International journal of diabetes in developing countries.》2022,42(4):606-613
International Journal of Diabetes in Developing Countries - Currently, gestational diabetes mellitus (GDM) is a major public health concern with a higher risk of adverse pregnancy outcomes for both... 相似文献
99.
Hypocretin-2 Saporin Lesions of the Ventrolateral Periaquaductal Gray (vlPAG) Increase REM Sleep in Hypocretin Knockout Mice 下载免费PDF全文
Satvinder Kaur Stephen Thankachan Suraiya Begum Meng Liu Carlos Blanco-Centurion Priyattam J. Shiromani 《PLoS Clinical Trials》2009,4(7)
Ten years ago the sleep disorder narcolepsy was linked to the neuropeptide hypocretin (HCRT), also known as orexin. This disorder is characterized by excessive day time sleepiness, inappropriate triggering of rapid-eye movement (REM) sleep and cataplexy, which is a sudden loss of muscle tone during waking. It is still not known how HCRT regulates REM sleep or muscle tone since HCRT neurons are localized only in the lateral hypothalamus while REM sleep and muscle atonia are generated from the brainstem. To identify a potential neuronal circuit, the neurotoxin hypocretin-2-saporin (HCRT2-SAP) was used to lesion neurons in the ventral lateral periaquaductal gray (vlPAG). The first experiment utilized hypocretin knock-out (HCRT-ko) mice with the expectation that deletion of both HCRT and its target neurons would exacerbate narcoleptic symptoms. Indeed, HCRT-ko mice (n=8) given the neurotoxin HCRT2-SAP (16.5 ng/23nl/sec each side) in the vlPAG had levels of REM sleep and sleep fragmentation that were considerably higher compared to HCRT-ko given saline (+39%; n=7) or wildtype mice (+177%; n=9). However, cataplexy attacks did not increase, nor were levels of wake or non-REM sleep changed. Experiment 2 determined the effects in mice where HCRT was present but the downstream target neurons in the vlPAG were deleted by the neurotoxin. This experiment utilized an FVB-transgenic strain of mice where eGFP identifies GABA neurons. We verified this and also determined that eGFP neurons were immunopositive for the HCRT-2 receptor. vlPAG lesions in these mice increased REM sleep (+79% versus saline controls) and it was significantly correlated (r=0.89) with loss of eGFP neurons. These results identify the vlPAG as one site that loses its inhibitory control over REM sleep, but does not cause cataplexy, as a result of hypocretin deficiency. 相似文献
100.
Nelson EJ Chowdhury A Harris JB Begum YA Chowdhury F Khan AI Larocque RC Bishop AL Ryan ET Camilli A Qadri F Calderwood SB 《Proceedings of the National Academy of Sciences of the United States of America》2007,104(48):19091-19096
At the International Centre for Diarrhoeal Disease Research, Bangladesh, one-half of the rice-water stool samples that were culture-positive for Vibrio cholerae did not contain motile V. cholerae by standard darkfield microscopy and were defined as darkfield-negative (DF(-)). We evaluated the host and microbial factors associated with DF status, as well as the impact of DF status on transmission. Viable counts of V. cholerae in DF(-) stools were three logs lower than in DF(+) stools, although DF(-) and DF(+) stools had similar direct counts of V. cholerae by microscopy. In DF(-) samples, non-V. cholerae bacteria outnumbered V. cholerae 10:1. Lytic V. cholerae bacteriophage were present in 90% of DF(-) samples compared with 35% of DF(+) samples, suggesting that bacteriophage may limit culture-positive patients from producing DF(+) stools. V. cholerae in DF(-) and DF(+) samples were found both planktonically and in distinct nonplanktonic populations; the distribution of organisms between these compartments did not differ appreciably between DF(-) and DF(+) stools. This biology may impact transmission because epidemiological data suggested that household contacts of a DF(+) index case were at greater risk of infection with V. cholerae. We propose a model in which V. cholerae multiply in the small intestine to produce a fluid niche that is dominated by V. cholerae. If lytic phage are present, viable counts of V. cholerae drop, stools become DF(-), other microorganisms bloom, and cholera transmission is reduced. 相似文献