全文获取类型
收费全文 | 2423篇 |
免费 | 251篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 88篇 |
妇产科学 | 22篇 |
基础医学 | 318篇 |
口腔科学 | 86篇 |
临床医学 | 247篇 |
内科学 | 436篇 |
皮肤病学 | 60篇 |
神经病学 | 138篇 |
特种医学 | 178篇 |
外科学 | 310篇 |
综合类 | 42篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 254篇 |
眼科学 | 173篇 |
药学 | 95篇 |
中国医学 | 1篇 |
肿瘤学 | 216篇 |
出版年
2023年 | 27篇 |
2020年 | 33篇 |
2019年 | 27篇 |
2018年 | 49篇 |
2017年 | 40篇 |
2016年 | 39篇 |
2015年 | 44篇 |
2014年 | 52篇 |
2013年 | 74篇 |
2012年 | 95篇 |
2011年 | 96篇 |
2010年 | 65篇 |
2009年 | 51篇 |
2008年 | 91篇 |
2007年 | 130篇 |
2006年 | 94篇 |
2005年 | 78篇 |
2004年 | 88篇 |
2003年 | 69篇 |
2002年 | 75篇 |
2001年 | 69篇 |
2000年 | 87篇 |
1999年 | 62篇 |
1998年 | 39篇 |
1997年 | 26篇 |
1996年 | 34篇 |
1995年 | 33篇 |
1994年 | 40篇 |
1993年 | 28篇 |
1992年 | 44篇 |
1991年 | 49篇 |
1990年 | 42篇 |
1989年 | 68篇 |
1988年 | 59篇 |
1987年 | 42篇 |
1986年 | 42篇 |
1985年 | 52篇 |
1984年 | 34篇 |
1983年 | 40篇 |
1982年 | 26篇 |
1981年 | 25篇 |
1980年 | 35篇 |
1979年 | 32篇 |
1978年 | 27篇 |
1977年 | 31篇 |
1976年 | 24篇 |
1975年 | 32篇 |
1974年 | 24篇 |
1973年 | 26篇 |
1972年 | 19篇 |
排序方式: 共有2685条查询结果,搜索用时 15 毫秒
101.
Gloria Peiró MD Encarna Adrover MD Jaime Guijarro MD Irene Ballester MD M. José Jimenez MD María Planelles MD Lluis Catasús BD 《The breast journal》2010,16(1):77-81
Abstract: Synchronous bilateral breast carcinoma (SBBC) and early onset are important characteristics of hereditary cases. The lifetime risk for breast carcinoma in Cowden syndrome (CS) is estimated to be 25–50%. We reported a 44‐year‐old woman presenting SBBC and characteristic mucocutaneous lesions of CS, confirmed by PTEN gene mutation analysis. Bilateral modified mastectomy and axillary dissection were performed. Histopathologic examination revealed a moderate‐differentiated invasive ductal carcinoma with mixed features of luminal A immunophenotype (Estrogen and/or Progesterone Receptors >50% and/or Ki67 < 30% of positive cells). The skin lesions showed the characteristic findings of tricholemmoma. Lack of PTEN expression was observed in all specimens. Sequencing analysis confirmed the presence of PTEN splice‐acceptor site mutation in intron 8 (c.1027‐2A>G), a germline mutation which had not been previously reported in CS. The patient received adjuvant chemotherapy and tamoxifen for 5 years. After 5 years of follow‐up, she persists recurrence‐free. SBBC with early onset suggests a hereditary predisposition. Thus, analysis of PTEN expression abnormality, easily assessed by immunohistochemistry, may be of clinical value to screen those patients with CS. 相似文献
102.
Brian D Rice Jörg Bätzing-Feigenbaum Victoria Hosegood Frank Tanser Caterina Hill Till Barnighausen Kobus Herbst Tanya Welz Marie-Louise Newell 《BMC public health》2007,7(1):160
Background
To present and compare population-based and antenatal-care (ANC) sentinel surveillance HIV prevalence estimates among women in a rural South African population where both provision of ANC services and family planning is prevalent and fertility is declining. With a need, in such settings, to understand how to appropriately adjust ANC sentinel surveillance estimates to represent HIV prevalence in general populations, and with evidence of possible biases inherent to both surveillance systems, we explore differences between the two systems. There is particular emphasis on unrepresentative selection of ANC clinics and unrepresentative testing in the population. 相似文献103.
S J Newell I W Booth M E Morgan G M Durbin A S McNeish 《Archives of disease in childhood》1989,64(6):780-786
Gastro-oesophageal reflux in very low birthweight infants was studied using a new 1 mm monocrystalline antimony oesophageal pH electrode. Gastro-oesophageal reflux was detected in 30 (85%) subjects. The mean (SEM) number of episodes of reflux in 24 hours was 12.1 (2.1), and 3.2 (0.6) lasted over five minutes. The mean reflux index was 4.5 (1.0)%, and the longest episode 17.1 (4.6) 17.1. Reflux was unrelated to postconceptional age or to resting lower oesophageal sphincter pressure. The mean reflux index was low at rest before feeds, being 1.8 (0.6)%, and increased slightly after feeds (3.8 (1.0)%), but was significantly increased after nursing care to 16.4 (3.0)%, and while xanthines were being given (5.9 (1.6)%. A subgroup of seven infants with xanthine resistant apnoea had severe gastro-oesophageal reflux that was not clinically apparent (reflux index 27.4 (3.6)%). Successful treatment of the reflux (reflux index: 3.6 (1.2)%) was associated with cessation of the apnoea. We conclude that gastro-oesophageal reflux is common, and is usually not clinically apparent, even when severe. It is important to consider gastro-oesophageal reflux in the differential diagnosis of xanthine resistant apnoea in preterm infants. 相似文献
104.
Stephen B. Freeman Ronald C. Hamaker Tod C. Huntley Richard Borrowdale William R. Rate Peter G. Garrett Newell Pugh 《The Laryngoscope》1995,105(6):575-578
Seventy-five patients who had advanced cervical metastasis with possible invasion of the deep muscles or carotid artery were approached with aggressive resection and intraoperative radiotherapy (IORT). All metastatic nodes were greater than 3 cm, 65% were fixed on clinical examination, and 35% involved the carotid artery. Forty-six (61%) of the patients had previously received irradiation. Fifteen of the patients required extended neck dissections with carotid resections and grafting. After the resection an average single dose of 2000 cGy of electron beam IORT was delivered. At 2 years, the local control rate within the IORT port was 68% and the absolute survival rate was 45%. Local control rates for close and microscopic margins (76% and 73%, respectively) were significantly better than the control rate for gross residual disease (25%, P<.05). The combination of extended neck dissection, including carotid artery resection if necessary, and IORT appears to offer improved control. 相似文献
105.
Dabis F Newell ML Fransen L Saba J Lepage P Leroy V Cartoux M Meda N Whynes DK Peckham C Nduati R Msellati P Vincenzi ID van de Perre P 《Health policy and planning》2000,15(1):34-42
OBJECTIVES: Different approaches to prevent mother-to-child transmission of HIV are being evaluated in developing countries. The first trials using a short regimen of zidovudine have been successful in Thailand, C?te d'Ivoire and Burkina Faso. International and local strategies are now being considered. The Ghent International Working Group on Mother-to-Child Transmission of HIV developed public health policy options to integrate these interventions into basic and maternal and child health (MCH) services. METHODS: The following tasks were undertaken: a critical review of randomized trials; an international pooled analysis of late postnatal transmission of HIV through breastfeeding; a review of the cost-effectiveness and cost-benefit of antiretroviral prophylaxis; a feasibility assessment of preventive strategies, including a postal survey on HIV voluntary counselling and testing (VCT) of pregnant women; the identification of requirements and research priorities for prenatal, obstetric and paediatric care. These projects provided the background for a three-day workshop in Ghent, Belgium, in November 1997. Conclusions were further refined, based on 1998 research findings. RESULTS: A summary of relevant evidence and ten public health recommendations are reported. VCT for pregnant women, a short regimen of zidovudine together with alternatives to breastfeeding currently represent the best option to reduce vertical transmission in most developing countries. The primary goal of the integrated package supporting these interventions is to alleviate overall maternal and infant morbidity and mortality. CONCLUSION: Prevention of mother-to-child transmission of HIV should now be considered for integration into basic health and MCH services of selected countries, with the involvement of governments and donor agencies. 相似文献
106.
Newell SY Wall VD Maruya KA 《Archives of environmental contamination and toxicology》2000,38(3):268-273
Ascomycetous fungi are the principal drivers of the decomposition of shoots of smooth cordgrass (Spartina alterniflora). Shoots of smooth cordgrass move into the saltmarsh food web via the decomposition system. Therefore, influences on saltmarsh
ascomycetes by pollutants of saltmarshes could have far-reaching impacts. Earlier examination of impacts of severe contamination
of a Georgia saltmarsh by mercury and polychlorinated biphenyls (PCBs) revealed little or no influence of the toxicants on
living standing crops or sexual productivities of cordgrass ascomycetes. Extension of the examination of saltmarsh-ascomycete
response to sites containing other toxic pollutants (the chlorinated organocyclic insecticide toxaphene; chromium, copper,
and lead; and polycyclic aromatic hydrocarbons [PAHs]) has shown that none of the additional toxicants engendered saltmarsh-fungal
responses in the form of reduced living standing crops or sexual productivities. Thus the ascomycetes of the cordgrass-decay
system appear to be as resistant to anthropogenic-pollutant poisoning as smooth cordgrass itself. Unless the fungal and plant
resistance mechanisms involve degradation of the toxicants, this may imply that saltmarshes are especially dangerous as receiving
sites for toxic waste because they may have the potential to readily move toxicants into the food web.
Received: 27 July 1999/Accepted: 29 September 1999 相似文献
107.
It is now known that with the use of antiretroviral prophylaxis with zidovudine, elective caesarean section delivery and refraining from breastfeeding the rate of mother-child transmission of HIV infection can be reduced to less than 2%. 相似文献
108.
The cellular pharmacology of methotrexate (MTX) is complex, involving the inhibition of both de novo thymidylate and purine biosynthesis. Measurement of MTX-induced inhibition of de novo thymidylate and purine biosynthesis may allow optimisation of MTX therapy, and the aim of this study was to develop an assay to measure the activity of both pathways in the same cell sample, and so determine the effects of MTX treatment. In situ thymidylate synthase (EC 2.1.1.45) activity was measured by the release of 3H2O from [5'-3H]deoxyuridine and de novo purine synthesis by the incorporation of [14C]formate into adenine and guanine. Incubation of human leukaemia CCRF-CEM cells for 22 hr with 50 nM MTX resulted in approximately 90% inhibition of in situ thymidylate synthase activity, relative to control untreated cells, and after exposure to 1000 nM MTX activity could not be detected. In contrast, de novo purine synthesis, measured in the same sample, was not inhibited by exposure to 50 nM MTX, although activity was again completely abolished by exposure to 1000 nM MTX. To demonstrate the utility of the assay, lymphoblasts isolated from a child with acute lymphoblastic leukaemia (ALL) were also incubated for 22 hr with 1000 nM MTX. Both in situ thymidylate synthase activity and de novo purine synthesis were significantly inhibited, by 70% and 60% respectively, relative to the activity in untreated cells. 相似文献
109.
Audeau A Newell P Dobbs BR Frizelle FA Kennedy R 《The New Zealand medical journal》2002,115(1148):69-72
AIM: To describe the effect of post-operative epidural analgesia on morbidity and mortality rates in a group of high-risk patients undergoing elective major abdominal surgery. METHODS: Retrospective chart review of patients in American Society of Anaesthetists Physical Status (ASA) category III or IV, who underwent elective major I or II general surgical procedures between 01/01/1996 and 01/09/1998. Patients were identified from a prospective audit database. Patients who had epidural analgesia or conventional parenteral opioids were compared for outcome measures. RESULTS: There were 167 patients identified (72 epidural, 95 non-epidural group). There was no significant difference in demographic data, inpatient stay, intensive care unit stay, or mortality rates (11% epidural v 17% non-epidural, p>0.05). There was no significant difference in morbidity rates, however there was a non-significant trend towards a lower morbidity in the epidural group. CONCLUSIONS: This study does not show any benefit from post-operative epidural analgesia on morbidity and mortality rates in high risk patients undergoing major abdominal surgery. It does illustrate that ASA 3 and 4 patients undergoing major abdominal surgery have a high morbidity and mortality. 相似文献
110.
Canan Koch SS Thoresen LH Tikhe JG Maegley KA Almassy RJ Li J Yu XH Zook SE Kumpf RA Zhang C Boritzki TJ Mansour RN Zhang KE Ekker A Calabrese CR Curtin NJ Kyle S Thomas HD Wang LZ Calvert AH Golding BT Griffin RJ Newell DR Webber SE Hostomsky Z 《Journal of medicinal chemistry》2002,45(23):4961-4974
A series of novel compounds have been designed that are potent inhibitors of poly(ADP-ribose) polymerase-1 (PARP-1), and the activity and physical properties have been characterized. The new structural classes, 3,4,5,6-tetrahydro-1H-azepino[5,4,3-cd]indol-6-ones and 3,4-dihydropyrrolo[4,3,2-de]isoquinolin-5-(1H)-ones, have conformationally locked benzamide cores that specifically interact with the PARP-1 protein. The compounds have been evaluated with in vitro cellular assays that measure the ability of the PARP-1 inhibitors to enhance the effect of cytotoxic agents against cancer cell lines. 相似文献