全文获取类型
收费全文 | 158184篇 |
免费 | 10544篇 |
国内免费 | 684篇 |
学科分类
医药卫生 | 169412篇 |
出版年
2023年 | 823篇 |
2022年 | 1395篇 |
2021年 | 3050篇 |
2020年 | 1856篇 |
2019年 | 3060篇 |
2018年 | 3568篇 |
2017年 | 2620篇 |
2016年 | 3016篇 |
2015年 | 3509篇 |
2014年 | 5042篇 |
2013年 | 7111篇 |
2012年 | 10729篇 |
2011年 | 11612篇 |
2010年 | 6378篇 |
2009年 | 5930篇 |
2008年 | 10165篇 |
2007年 | 10937篇 |
2006年 | 10376篇 |
2005年 | 10518篇 |
2004年 | 9824篇 |
2003年 | 9109篇 |
2002年 | 8727篇 |
2001年 | 1517篇 |
2000年 | 1138篇 |
1999年 | 1591篇 |
1998年 | 1884篇 |
1997年 | 1551篇 |
1996年 | 1273篇 |
1995年 | 1210篇 |
1994年 | 1030篇 |
1993年 | 1048篇 |
1992年 | 888篇 |
1991年 | 817篇 |
1990年 | 712篇 |
1989年 | 653篇 |
1988年 | 665篇 |
1987年 | 632篇 |
1986年 | 534篇 |
1985年 | 668篇 |
1984年 | 802篇 |
1983年 | 723篇 |
1982年 | 935篇 |
1981年 | 850篇 |
1980年 | 772篇 |
1979年 | 481篇 |
1978年 | 475篇 |
1977年 | 472篇 |
1976年 | 401篇 |
1975年 | 338篇 |
1974年 | 369篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Philip Steer 《BJOG : an international journal of obstetrics and gynaecology》2005,112(S1):109-112
Until recently, bioethics (ethics related to biology or, more specifically, in the context of preterm labour, medical ethics) was considered mainly to relate to the active treatment or investigation of patients. Collection of data, excised specimens or even whole organs was considered to be relatively uncontentious as it did not impinge directly upon the health of the individual concerned. However, in the UK in particular, the practice of collecting data, tissues or even whole organs has recently come under the spotlight of public scrutiny, particularly following the Alder Hey Enquiry. Coincidentally with a decline in public confidence in the probity of authority, medical scientists increasingly have to justify the accumulation of data about individuals. 相似文献
64.
Bill J Gurley Ashley Swain Gary W Barone D Keith Williams Philip Breen C Ryan Yates Leslie B Stuart Martha A Hubbard Yudong Tong Sreekhar Cheboyina 《Drug metabolism and disposition》2007,35(2):240-245
Phytochemical-mediated modulation of P-glycoprotein (P-gp) and other drug transporters may give rise to many herb-drug interactions. Serial plasma concentration-time profiles of the P-gp substrate, digoxin, were used to determine whether supplementation with goldenseal or kava kava modified P-gp activity in vivo. Twenty healthy volunteers were randomly assigned to receive a standardized goldenseal (3210 mg daily) or kava kava (1227 mg daily) supplement for 14 days, followed by a 30-day washout period. Subjects were also randomized to receive rifampin (600 mg daily, 7 days) and clarithromycin (1000 mg daily, 7 days) as positive controls for P-gp induction and inhibition, respectively. Digoxin (Lanoxin, 0.5 mg) was administered p.o. before and at the end of each supplementation and control period. Serial digoxin plasma concentrations were obtained over 24 h and analyzed by chemiluminescent immunoassay. Comparisons of area under the curve (AUC)((0-3)), AUC((0-24)), C(max,) CL/F, and elimination half-life were used to assess the effects of goldenseal, kava kava, rifampin, and clarithromycin on digoxin pharmacokinetics. Rifampin produced significant reductions (p < 0.01) in AUC((0-3)), AUC((0-24)), CL/F, t(1/2), and C(max), whereas clarithromycin increased these parameters significantly (p < 0.01). With the exception of goldenseal's effect on C(max) (14% increase), no statistically significant effects on digoxin pharmacokinetics were observed following supplementation with either goldenseal or kava kava. When compared with rifampin and clarithromycin, supplementation with these specific formulations of goldenseal or kava kava did not appear to affect digoxin pharmacokinetics, suggesting that these supplements are not potent modulators of P-gp in vivo. 相似文献
65.
Preclinical and clinical investigations currently underway are employing novel strategies for combining vaccines with conventional and experimental anticancer therapies. To date, the FDA has not approved a therapeutic cancer vaccine. However, the results of recent investigations suggest an increasing role for vaccines in new models of combination therapy for many types of cancer. This article reviews and discusses therapeutic cancer strategies that employ vaccines in combination with local radiation, chemotherapy, hormone therapy, and anti-CTLA-4 mAb. Preclinical studies have shown that certain anticancer agents have immune modulatory effects that result in up-regulation of surface expression of MHC molecules, tumor-associated antigens, or Fas on malignant cells, rendering them more susceptible to immune destruction. Preliminary results of clinical studies using combination strategies have demonstrated a postvaccination antigen cascade, prolonged time to disease progression, and improved overall survival. Several larger randomized trials are ongoing, and more are required to support these findings. 相似文献
66.
Paul N Bennett Leo Breugelmans Anthony Meade Dee Parkhurst 《Journal of renal nutrition》2006,16(1):59-62
OBJECTIVE: To assess the reliability of a nurse-performed nutrition screening tool (NST) for hemodialysis (HD) patients to identify nutritionally at-risk patients. DESIGN: Tool reliability assessment. SETTING AND PARTICIPANTS: The setting was nine non-hospital private (n = 3) and public (n = 6) HD units in Australia (two rural and seven metropolitan). Participants were 112 HD patients. RESULTS: A total of 112 HD patients (male = 65, female = 47) from 9 non-hospital HD units in Australia (seven metropolitan and two rural) were screened with the NST and the outcome of dietitian referral compared with Standard Dietitians Assessment. The mean age of patients was 57.6 years. Overall, the NST showed a sensitivity of 0.84 (range, 0.71 to 0.94; P < .05) and a specificity of 0.9 (range, 0.82 to 0.98; P < .05). The NST was more sensitive (sensitivity, 0.93 [range, 0.87 to 0.99; P < .05]) and was more specific for men (specificity, 0.92 [range, 0.85 to 0.99; P < .05]). Specificity was very strong in metropolitan patients (specificity, 0.94 [range, 0.87 to 1.01; P < .05]). CONCLUSIONS: The tool was more sensitive and specific than the NST previously reported by the same investigators. The tool is particularly specific in that it screens those patients not requiring dietitian intervention. The use of this tool may benefit HD units that do not have on-site or regular dietetic support to prioritize patients needing dietitian intervention. 相似文献
67.
68.
69.
Paul J Huggan David R Murdoch 《Clinical infectious diseases》2007,45(12):1647-8; author reply 1649-51
70.
Neal G Palmer James R Yacyshyn Herbert C Northcott Brian Nebbe Paul W Major 《American journal of orthodontics and dentofacial orthopedics》2005,128(2):163-167
INTRODUCTION: To plan for future acceptance and implementation of computer-related technology, it is necessary to understand orthodontists' current perceptions and attitudes toward emerging technologies. METHODS: An anonymous, self-administered, mail-out survey of Canadian orthodontists was conducted. The response rate was 45.6% (304/667). RESULTS: Most orthodontists indicated that computer technology could improve current practice efficiency and quality of patient care. Only 15% reported that digital models are quite or very useful; 73.6%, 69.1%, 55%, and 37.4% agreed or strongly agreed with using digital and electronic technology to consult with other dental specialists, other orthodontists, general dentists, and the public, respectively. Cost of the technology was reported as a significant or insurmountable obstacle by 54% of the respondents. Interprovincial legislation, unclear consultation remuneration guidelines, and lack of comfort with the technology were not perceived as significant obstacles. Only 36% reported security or privacy issues as a significant or insurmountable obstacle. CONCLUSIONS: Canadian orthodontists seem to view digital and electronic technology as useful and capable of improving their offices' efficiency and production. Although they are sensitive to some potential obstacles, they are willing to overcome these and incorporate the technology into their practices. 相似文献