全文获取类型
收费全文 | 1379篇 |
免费 | 88篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 27篇 |
妇产科学 | 30篇 |
基础医学 | 211篇 |
口腔科学 | 23篇 |
临床医学 | 187篇 |
内科学 | 284篇 |
皮肤病学 | 33篇 |
神经病学 | 135篇 |
特种医学 | 107篇 |
外科学 | 84篇 |
综合类 | 3篇 |
预防医学 | 143篇 |
眼科学 | 20篇 |
药学 | 81篇 |
中国医学 | 1篇 |
肿瘤学 | 97篇 |
出版年
2023年 | 18篇 |
2022年 | 53篇 |
2021年 | 69篇 |
2020年 | 30篇 |
2019年 | 46篇 |
2018年 | 40篇 |
2017年 | 33篇 |
2016年 | 32篇 |
2015年 | 28篇 |
2014年 | 53篇 |
2013年 | 59篇 |
2012年 | 90篇 |
2011年 | 87篇 |
2010年 | 56篇 |
2009年 | 53篇 |
2008年 | 91篇 |
2007年 | 85篇 |
2006年 | 86篇 |
2005年 | 85篇 |
2004年 | 67篇 |
2003年 | 51篇 |
2002年 | 52篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 14篇 |
1994年 | 5篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1947年 | 3篇 |
1932年 | 2篇 |
1931年 | 3篇 |
1921年 | 3篇 |
1915年 | 2篇 |
排序方式: 共有1474条查询结果,搜索用时 62 毫秒
81.
Heregulin (HRG) is an activator of the erbB2-, erbB3- and erbB4-(erbB-2/3/4) signaling pathway. Transfection of full-length HRG cDNA into the estrogen (E2)-dependent cell line MCF-7 promoted an invasive E2-independent phenotype, as well as persistent activation of the erbB-2/3/4 receptors. Moreover, HRG expression in MCF-7 cells renders the cells sensitive to the topoisomerase II inhibitor doxorubicin (Doxo). In an attempt to dissociate the tumorigenic effect of HRG from the sensitizing effect to chemotherapy, we constructed a structural deletion mutant of HRG. Transfection of the deletion mutant of HRG described in this study (HRG/M) into MCF-7 cells resulted in the dissociation of the tumor-promoting activity of HRG from the sensitization to Doxo, that is, although the cells did not become more aggressive or E2-independent they became more sensitive to Doxo. HRG/M was unable to autophosphorylate the erbB receptors and did not affect the level of MAPK phosphorylation. Furthermore, the intracellular localization of the protein was different from that of the full-length protein. Our data show that the HRG/M sequences are sufficient to sensitize MCF-7 cells to Doxo, and provide evidence that this sensitization is independent of erbB2 activation. 相似文献
82.
Copeland MP Daly E Hines V Mastromauro C Zaitchik D Gunther J Albert M 《Alzheimer disease and associated disorders》2003,17(1):1-8
The aim of this study was to determine the prevalence of psychiatric symptoms among nondemented individuals with memory changes and whether such symptoms predict progression of functional decline or diagnosis of Alzheimer disease (AD). A semi-structured interview was administered at baseline to controls (n = 32) and to nondemented subjects with memory changes (n = 112) and to each subject's collateral source. The interview assessed the impact of cognition on functional abilities in daily life and a variety of psychiatric symptoms, including symptoms of psychosis, depression, and personality change. Participants were followed annually for 3 years to determine who had progressive functional decline and who progressed to meet clinical criteria for AD. Those diagnosed with AD on follow-up had more symptoms of personality change, such as agitation and passivity, at baseline than those who did not progress to meet clinical criteria for AD. Mild depressive symptoms were also more common among individuals at baseline who subsequently 'converted' to AD. Symptoms of personality change were associated with a more rapid increase in functional difficulty over time, whereas depressive symptoms were not. Changes in personality are more common among subjects with memory changes who go on to develop AD. Particular types of personality change, such as agitation and passivity, are related to progression of functional difficulty over time. Depressive symptoms, although common in prodromal AD, are not associated with a more rapid functional decline. 相似文献
83.
Qualitative methods are increasingly used to explain complex concepts within nursing practice. This paper defines qualitative research and offers practical advice for getting started and interpreting such research. Phenomenology, ethnography and grounded theory are explored briefly, with examples of research projects. Data collection and analysis are also discussed. 相似文献
84.
85.
Estrogen receptors (ER) were estimated in tissue of endometrial and cervical cancers. At the same time sex hormone-binding globulin (SHBG) was measured in the blood of the patients and in normal pre- and postmenopausal controls. The average SHBG level was significantly higher in postmenopausal patients with ER-positive endometrial or cervical cancers than in patients with ER-negative cancers. There was no correlation between the SHBG levels in plasma and the receptor levels in tissue in either ER-positive or ER-negative tissues. The average SHBG value in postmenopausal patients with ER-positive endometrial cancer was similar to the average value found in normal premenopausal women. In premenopausal patients with cervical cancer there was no difference in SHBG values between ER-positive and ER-negative cancers. 相似文献
86.
Pike VW Halldin C Nobuhara K Hiltunen J Mulligan RS Swahn CG Karlsson P Olsson H Hume SP Hirani E Whalley J Pilowsky LS Larsson S Schnell PO Ell PJ Farde L 《European journal of nuclear medicine and molecular imaging》2003,30(11):1520-1528
Single-photon emission tomography (SPET) and positron emission tomography (PET), when coupled to suitable radioligands, are uniquely powerful for investigating the status of neurotransmitter receptors in vivo. The serotonin subtype-4 (5-HT4) receptor has discrete and very similar distributions in rodent and primate brain. This receptor population may play a role in normal cognition and memory and is perhaps perturbed in some neuropsychiatric disorders. SB 207710 [(1-butyl-4-piperidinylmethyl)-8-amino-7-iodo-1,4-benzodioxan-5-carboxylate] is a selective high-affinity antagonist at 5-HT4 receptors. We explored radioiodinated SB 207710 as a possible radioligand for imaging 5-HT4 receptors in vivo. Rats were injected intravenously with iodine-125 labelled SB 207710, euthanised at known times and dissected to establish radioactivity content in brain tissues. Radioactivity entered brain but cleared rapidly and to a high extent from blood and plasma. Between 45 and 75 min after injection, the ratios of radioactivity concentration in each of 12 selected brain tissues to that in receptor-poor cerebellum correlated with previous measures of 5-HT4 receptor density distribution in vitro. The highest ratio was about 3.4 in striatum. SB 207710 was labelled with iodine-123 by an iododestannylation procedure. A cynomolgus monkey was injected intravenously with [123I]SB 207710 and examined by SPET. Maximal whole brain uptake of radioactivity was 2.3% of the injected dose at 18 min after radioligand injection. Brain images acquired between 9 and 90 min showed high radioactivity uptake in 5-HT4 receptor-rich regions, such as striatum, and low uptake in receptor-poor cerebellum. At 169 min the ratio of radioactivity concentration in striatum to that in cerebellum was 4.0. In a second SPET experiment, the cynomolgus monkey was pretreated with a selective 5-HT4 receptor antagonist, SB 204070, at 20 min before [123I]SB 207710 injection. Radioactivity in all brain regions was reduced almost to the level in cerebellum by 176 min after radioligand injection. These findings show that [123I]SB 207710 is an effective radioligand for imaging brain 5-HT4 receptors in vivo.For preliminary accounts of this work, see Pike VW et al., J Nucl Med 1998; 39 (Suppl):185; Eur J Nucl Med 1999; 26:991. 相似文献
87.
Mendelson E Aboudy Y Smetana Z Tepperberg M Grossman Z 《Reproductive toxicology (Elmsford, N.Y.)》2006,21(4):350-382
Viral infections during pregnancy may cause fetal or neonatal damage. Clinical intervention, which is required for certain viral infections, relies on laboratory tests performed during pregnancy and at the neonatal stage. This review describes traditional and advanced laboratory approaches and testing methods used for assessment of the six most significant viral infections during pregnancy: rubella virus (RV), cytomegalovirus (CMV), varicella-zoster virus (VZV), herpes simplex virus (HSV), parvovirus B19 and human immunodeficiency virus (HIV). Interpretation of the laboratory tests results according to studies published in recent years is discussed. 相似文献
88.
mclafferty e., dingwall l. & halkett a. (2009) Using gaming workshops to prepare nursing students for caring for older people in clinical practice. International Journal of Older People Nursing 5 , 51–60
doi: 10.1111/j.1748-3743.2009.00176.x
Background. Older people are the least satisfied with the care they receive when they are acutely ill. Furthermore, within nurse education, nursing older people has been submerged rather than embedded in the acute focus of nursing curricula. Lecturers designed a 1-day gaming workshop to stimulate interest in nursing older people.
Aim. To explore the influence of gaming workshops on undergraduate nursing students' learning about nursing older people.
Methods. Both quantitative and qualitative methods were used. A survey questionnaire was distributed pre- and postgaming workshops to a cohort of second year nursing students ( n = 100, 86% response rate). Students ( n = 9) were invited to participate in a semi-structured interview on completion of their placement.
Findings. Responses were significantly more positive for the questionnaire postworkshop when compared with the responses of preworkshop. Five themes were identified from the interviews, they included teacher interaction; level of student engagement with the topic; the effect of the teaching method; influence of the workshops on practice; working with older people.
Implications for practice. Nursing students preferred this novel teaching method to lectures. They learned about appropriate and relevant care of older people, however, they seem to struggle to apply concepts related to caring for older people in the acute settings. 相似文献
doi: 10.1111/j.1748-3743.2009.00176.x
Background. Older people are the least satisfied with the care they receive when they are acutely ill. Furthermore, within nurse education, nursing older people has been submerged rather than embedded in the acute focus of nursing curricula. Lecturers designed a 1-day gaming workshop to stimulate interest in nursing older people.
Aim. To explore the influence of gaming workshops on undergraduate nursing students' learning about nursing older people.
Methods. Both quantitative and qualitative methods were used. A survey questionnaire was distributed pre- and postgaming workshops to a cohort of second year nursing students ( n = 100, 86% response rate). Students ( n = 9) were invited to participate in a semi-structured interview on completion of their placement.
Findings. Responses were significantly more positive for the questionnaire postworkshop when compared with the responses of preworkshop. Five themes were identified from the interviews, they included teacher interaction; level of student engagement with the topic; the effect of the teaching method; influence of the workshops on practice; working with older people.
Implications for practice. Nursing students preferred this novel teaching method to lectures. They learned about appropriate and relevant care of older people, however, they seem to struggle to apply concepts related to caring for older people in the acute settings. 相似文献
89.
Chronic obstructive pulmonary disease is a syndrome including illnesses such as asthma, chronic bronchitis, and emphysema. Although these diseases share a common obstructive component, their optimal treatment and prognosis differ. This article examines the salient features of the history, physical exam, pulmonary function tests, and radiological evaluation which may allow the clinician to differentiate the various diseases that make up COPD; thus allowing the clinician to better target the multiple therapeutic modalities available. 相似文献
90.
Nagendra R. Hegde Deepak Kumar P. Panduranga Rao P. Krishna Kumari Yashpal Kaushik R. Ravikrishnan Sai D. Prasad Krishna M. Ella 《Vaccine》2014
Several limitations of the use of embryonated eggs and the threat of pandemics have highlighted the need for other platforms for the production of influenza vaccines. We report the indigenous development and pre-clinical testing of an MDCK-based H1N1 pandemic influenza vaccine HNVAC from India. The cell bank and virus seed were characterized extensively. The cells were characterized by PCR, electron microscopy, and karyotyping, and found to be of female canine epithelial origin. The virus was confirmed by neutralization, haemagglutination inhibition, neuraminidase inhibition, and PCR and nucleotide sequencing. Adventitious agent testing was performed by both in vitro and in vivo studies. The in vitro studies included culturing, haemadsorption, haemagglutination, PCR and RT-PCR, whereas in vivo studies included passage in embryonated eggs and in laboratory animals. Both cell bank and virus seed were free of adventitious agents. MDCK cell lysates as well as cellular DNA did not produce tumours in newborn or adult laboratory animals. The bioprocess parameters were standardized to recover antigen with minimal levels of process-related impurities. The vaccine bulk was tested for the presence of specific antigen, and quantified by single radial immunodiffusion. Finally, non-adjuvanted and aluminium hydroxide adjuvanted vaccine formulations were found to be safe in preclinical toxicity studies in mice, rats, guinea pigs and rabbits, and immunogenic in mice and rabbits. This is the first and only cell culture-based influenza vaccine platform developed in any developing country. 相似文献