全文获取类型
收费全文 | 50180篇 |
免费 | 3749篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 414篇 |
儿科学 | 2110篇 |
妇产科学 | 1503篇 |
基础医学 | 6585篇 |
口腔科学 | 523篇 |
临床医学 | 6754篇 |
内科学 | 9423篇 |
皮肤病学 | 767篇 |
神经病学 | 4938篇 |
特种医学 | 1056篇 |
外国民族医学 | 38篇 |
外科学 | 4821篇 |
综合类 | 544篇 |
一般理论 | 99篇 |
预防医学 | 7286篇 |
眼科学 | 676篇 |
药学 | 2672篇 |
中国医学 | 87篇 |
肿瘤学 | 3750篇 |
出版年
2024年 | 77篇 |
2023年 | 495篇 |
2022年 | 725篇 |
2021年 | 1551篇 |
2020年 | 930篇 |
2019年 | 1463篇 |
2018年 | 1705篇 |
2017年 | 1235篇 |
2016年 | 1312篇 |
2015年 | 1388篇 |
2014年 | 1938篇 |
2013年 | 2820篇 |
2012年 | 4003篇 |
2011年 | 4112篇 |
2010年 | 2182篇 |
2009年 | 1903篇 |
2008年 | 3429篇 |
2007年 | 3389篇 |
2006年 | 3128篇 |
2005年 | 3058篇 |
2004年 | 2764篇 |
2003年 | 2468篇 |
2002年 | 2307篇 |
2001年 | 332篇 |
2000年 | 211篇 |
1999年 | 335篇 |
1998年 | 467篇 |
1997年 | 356篇 |
1996年 | 297篇 |
1995年 | 315篇 |
1994年 | 262篇 |
1993年 | 230篇 |
1992年 | 153篇 |
1991年 | 158篇 |
1990年 | 139篇 |
1989年 | 115篇 |
1988年 | 117篇 |
1987年 | 108篇 |
1986年 | 125篇 |
1985年 | 129篇 |
1984年 | 136篇 |
1983年 | 125篇 |
1982年 | 131篇 |
1981年 | 166篇 |
1980年 | 113篇 |
1979年 | 81篇 |
1978年 | 75篇 |
1977年 | 71篇 |
1976年 | 68篇 |
1972年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Elizabeth A. Mosley PhD MPH Amy J. Schulz PhD MPH MSW Lisa H. Harris MD PhD Barbara A. Anderson PhD 《Women & health》2020,60(7):806-820
ABSTRACT Abortion is legal in South Africa, but negative abortion attitudes remain common and are poorly understood. We used nationally representative South African Social Attitudes Survey data to analyze abortion attitudes in the case of fetal anomaly and in the case of poverty from 2007 to 2016 (n = 20,711; ages = 16+). We measured correlations between abortion attitudes and these important predictors: religiosity, attitudes about premarital sex, attitudes about preferential hiring and promotion of women, and attitudes toward family gender roles. Abortion acceptability for poverty increased over time (b = 0.05, p < .001), but not for fetal anomaly (b = ?0.008, p = .284). Highly religious South Africans reported lower abortion acceptability in both cases (Odds Ratio (OR)anomaly = 0.85, p = .015; ORpoverty = 0.84, p = .02). Premarital sex acceptability strongly and positively predicted abortion acceptability (ORanomaly = 2.63, p < .001; ORpoverty = 2.46, p < .001). Attitudes about preferential hiring and promotion of women were not associated with abortion attitudes, but favorable attitudes about working mothers were positively associated with abortion acceptability for fetal anomaly ((ORanomaly = 1.09, p = .01; ORpoverty = 1.02, p = .641)). Results suggest negative abortion attitudes remain common in South Africa and are closely tied to religiosity, traditional ideologies about sexuality, and gender role expectations about motherhood. 相似文献
2.
Erin L. Sutfin Jennifer Cornacchione Ross Allison J. Lazard Elizabeth Orlan Cynthia K. Suerken Kimberly D. Wiseman 《Health communication》2019,34(3):343-351
ABSTRACTAdolescents and young adults smoke waterpipe tobacco (WT) and cigarillos, at least in part, based on erroneous beliefs that these products are safer than cigarettes. To address this challenge, we used a systematic, three-phase process to develop a health communication campaign to discourage WT and cigarillo smoking among at-risk (tobacco users and susceptible non-users) 16- to 25-year-olds. In Phase 1, we used a national phone survey (N = 896) to determine salient message beliefs. Participants reported constituents (i.e., harmful chemicals) emitted by the products were worrisome. In Phase 2, we developed and evaluated four message executions, with varying imagery, tone, and unappealing products with the same constituents, using focus groups (N = 38). Participants rated one execution highly, resulting in our development of a campaign where each message: (1) identified a tobacco product and constituent in the smoke; (2) included an image of an unappealing product containing the constituent (e.g., pesticides, gasoline) to grab attention; and (3) used a humorous sarcastic tone. In Phase 3, we tested the campaign messages (17 intervention and six control) with a nationally representative online survey (N = 1,636). Participants rated intervention and control messages highly with few differences between them. Exposure to messages resulted in significant increases in all risk beliefs from pre to post (p < 0.05). For WT, intervention messages increased beliefs about addiction more than control messages (p < 0.05). This systematic, iterative approach resulted in messages that show promise for discouraging WT and cigarillo use. 相似文献
3.
4.
Elizabeth C Frenzel Georgia A Thomas Hend A Hanna 《Infection control and hospital epidemiology》2006,27(5):512-514
At the time of hire, 4059 of 6522 healthcare workers required a 2-step tuberculin skin test; 114 workers (2.8%) demonstrated a boosted reaction after the second step. Boosted reactions were significantly associated with male sex and older age. A verbal history of previous tuberculin skin test results was not a reliable indicator of baseline tuberculin skin test status at the time of hire. 相似文献
5.
6.
Elizabeth Campbell Ph.D. Danna Peterkin R.N. Richard Abbott M.B. B.S. John Rogers M.B. B.S. 《Preventive medicine》1997,26(6):801-807
Background.Computers that collect data from patients and provide both patients and practitioners with printed feedback on a range of health risks are a tool for assisting general practitioners with preventive care. This study assessed the impact of computer-generated printed feedback on cervical screening among women who were underscreened for cervical cancer.Method.Female attenders at two Australian general practices were randomly allocated to Experimental or Control groups. Women in both groups completed a health risk survey on a touch screen computer prior to their consultation. Those in the Experimental group received printed pages summarizing their results, including their eligibility for cervical screening and last Pap test, for themselves and their doctor. The number and proportion of underscreened women who had a Pap test in the 6 months after completing the computer survey, as determined by pathology records, were examined.Results.Of the 679 participants, 139 were classified as underscreened on the basis of self-report (74 Experimental, 65 Control) and 272 on the basis of their pathology records (148 Experimental, 124 Control). Overall about one-third of women had a test in the 6-month period, and the differences between the groups were not significant for women overall (18–70 years) or for women 18–49 years. Among women 50–70 who were underscreened based on self-report, those receiving the printout were more likely to have a Pap test in the next 6 months (P< 0.05). This pattern was also evident, but did not reach statistical significance, for older women who were underscreened based on pathology records.Conclusions.We are unable to draw conclusions regarding the effectiveness of the computer system due to the modest proportions of women screened, the small numbers, and the fact that the computer survey may have created an intervention effect in the Control group. As the study suggests the computer system is acceptable to women and may be effective for encouraging screening among older women, further exploration of the system is desirable. 相似文献
7.
Juin Fok-Seang Linda C. Smith-Thomas Sally Meiners Elizabeth Muir Jian-Sheng Du Elizabeth Housden Alan R. Johnson Andreas Faissner Herbert M. Geller Roger J. Keynes John H. Rogers James W. Fawcett 《Brain research》1995,689(2):207
The adult mammalian central nervous system (CNS) lacks the capacity to support axonal regeneration. There is increasing evidence to suggest that astrocytes, the major glial population in the CNS, may possess both axon-growth promoting and axon-growth inhibitory properties and the latter may contribute to the poor regenerative capacity of the CNS. In order to examine the molecular differences between axon-growth permissive and axon-growth inhibitory astrocytes, a panel of astrocyte cell lines exhibiting a range of axon-growth promoting properties was generated and analysed. No clear correlation was found between the axon-growth promoting properties of these astrocyte cell lines with: (i) the expression of known neurite-outgrowth promoting molecules such as laminin, fibronectin andN-cadherin; (ii) the expression of known inhibitory molecules such tenascin and chondroitin sulphate proteoglycan; (iii) plasminogen activator and plasminogen activator inhibitor activity; and (iv) growth cone collapsing activity. EM studies on aggregates formed from astrocyte cell lines, however, revealed the presence of an abundance of extracellular matrix material associated with the more inhibitory astrocyte cell lines. When matrix deposited by astrocyte cell lines was assessed for axon-growth promoting activity, matrix from permissive lines was found to be a good substrate, whereas matrix from the inhibitory astrocyte lines was a poor substrate for neuritic growth. Our findings, taken together, suggest that the functional differences between the permissive and the inhibitory astrocyte cell lines reside largely with the ECM. 相似文献
8.
Timothy Threlfall Neil Kent Peter Garcia-Webb Elizabeth Byrnes Paul Psaila-Savona 《Australian and New Zealand journal of public health》1993,17(4):379-381
Abstract: This study reports on an analysis of the lead concentrations in 123 venous blood samples collected from Perth children aged between two months and 17 years attending Princess Margaret Hospital. The overall geometric mean was 6.9 μg lead per 100 ml whole blood, with 95 per cent of results lying between 3.2 and 14.8 μg/100 ml. Among children under five years of age, those aged between 18 months and two years had the highest geometric mean blood lead (11.1 μg/100 ml). There were no consistent associations between geometric mean blood lead and area of residence, age group or sex. In this sample of Perth children, the mean blood lead concentration was lower than those reported in other studies. Less than 0.1 per cent of children of the age range studied would have been expected to have lead levels exceeding the NHMRC ‘level of concern’ (25 μg/100 ml) current at the time of the study. However, the recent adoption of goal of less than 10 μg/100 ml could mean that lead levels in up to 21 per cent of Perth children would now be regarded as excessive. 相似文献
9.
Janet M Powell Sonya L Griffith Elizabeth M Kanny 《The American journal of occupational therapy》2005,59(4):467-474
PURPOSE: To provide a model for assessing occupational therapy workforce needs by using a demand-based approach to determine current workforce status in the Northwest region. Regional information may have implications for addressing national occupational therapy service needs. METHOD: A questionnaire was sent to a proportional random sample of 234 facilities that hire occupational therapy practitioners. Data were collected in July-August 2003 using structured mailing and follow-up procedures. RESULTS: Response rate was 79%. Twenty-four percent reported occupational therapy vacancies and 11% occupational therapy assistant vacancies; 48% predicted an increase in occupational therapy positions in the next 2 years and 41% an increase in occupational therapy assistant positions. Sixty-three percent of respondents reported difficulty in hiring. DISCUSSION: This study identifies an occupational therapy workforce shortage in the Northwest. Management of a shortage is critical, for even short-term adjustments could lead to permanent changes in service provision. This study demonstrates the importance of current information on the status of the national workforce and serves as a model for future studies. 相似文献
10.
Emmanuel J Favaloro Roslyn Bonar Elizabeth Duncan Susan Rodgers Katherine Marsden 《Blood coagulation & fibrinolysis》2007,18(5):441-448
The PFA-100 is a relatively new laboratory instrument, first described in 1995. There have since been numerous studies assessing its utility as a screening tool for platelet dysfunction and/or von Willebrand's disease (VWD). The PFA-100 displays variable sensitivity to different types of platelet disorders, as well as to antiplatelet medication (e.g. aspirin), with similar caveats for monitoring of primary haemostasis-promoting therapies in platelet dysfunction. There is therefore considerable uncertainty regarding its utility within this context, and we have accordingly performed an audit of usage among participants of the Royal College of Pathologists of Australasia Quality Assurance Program. Of 105 laboratories surveyed, 40 responded that they performed platelet function testing, with 26 (65%) further indicating they utilized the PFA-100. We report a wide variety of laboratory usage among these users, including numbers of tests performed [annual median (range) = 270 (15-6000)], sources of requests (clinical sources and localities), testing criteria and follow-up action. Most tests were completed within 4 h of collection, as recommended by the manufacturer, and most tests were performed as a replacement, or as a preliminary screen of platelet function (i.e. classical aggregation). Most abnormal findings, however, were attributed to antiplatelet medication such as aspirin. 相似文献