全文获取类型
收费全文 | 49194篇 |
免费 | 3692篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 389篇 |
儿科学 | 2090篇 |
妇产科学 | 1463篇 |
基础医学 | 6462篇 |
口腔科学 | 498篇 |
临床医学 | 6669篇 |
内科学 | 9224篇 |
皮肤病学 | 766篇 |
神经病学 | 4844篇 |
特种医学 | 1028篇 |
外国民族医学 | 38篇 |
外科学 | 4711篇 |
综合类 | 510篇 |
一般理论 | 99篇 |
预防医学 | 7155篇 |
眼科学 | 674篇 |
药学 | 2613篇 |
中国医学 | 85篇 |
肿瘤学 | 3685篇 |
出版年
2024年 | 76篇 |
2023年 | 492篇 |
2022年 | 721篇 |
2021年 | 1532篇 |
2020年 | 920篇 |
2019年 | 1448篇 |
2018年 | 1692篇 |
2017年 | 1228篇 |
2016年 | 1301篇 |
2015年 | 1373篇 |
2014年 | 1921篇 |
2013年 | 2795篇 |
2012年 | 3964篇 |
2011年 | 4069篇 |
2010年 | 2162篇 |
2009年 | 1887篇 |
2008年 | 3401篇 |
2007年 | 3362篇 |
2006年 | 3092篇 |
2005年 | 3031篇 |
2004年 | 2738篇 |
2003年 | 2439篇 |
2002年 | 2289篇 |
2001年 | 305篇 |
2000年 | 194篇 |
1999年 | 309篇 |
1998年 | 457篇 |
1997年 | 342篇 |
1996年 | 293篇 |
1995年 | 302篇 |
1994年 | 256篇 |
1993年 | 226篇 |
1992年 | 132篇 |
1991年 | 136篇 |
1990年 | 121篇 |
1989年 | 104篇 |
1988年 | 108篇 |
1987年 | 76篇 |
1986年 | 97篇 |
1985年 | 105篇 |
1984年 | 117篇 |
1983年 | 102篇 |
1982年 | 121篇 |
1981年 | 158篇 |
1980年 | 105篇 |
1979年 | 64篇 |
1978年 | 57篇 |
1977年 | 60篇 |
1976年 | 58篇 |
1974年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Laura K Brennan Elizabeth A Baker Debra Haire-Joshu Ross C Brownson 《Health education & behavior》2003,30(6):740-755
Although the relationship of psychosocial factors to physical activity has been explored, there is increased interest in how perceptions of the community environment influence behavior. However, few methodological studies have incorporated perceptions of the social and community environment (protective social factors) or addressed key measurement issues. Computer-assisted telephone interviews were administered to a national sample of 1,818 U.S. adults. Unadjusted and multivariate-adjusted odds ratios were calculated to compare active and inactive participants by Protective Social Factors (PSF) scores and selected sociodemographics. Confirmatory factor analysis and reliability analysis suggested strong PSF scale psychometric properties (alpha = .92). After adjustment for potential confounders, a 10-point rise in the PSF score resulted in a 12% increased likelihood of meeting Centers for Disease Control and Prevention/American College of Sports Medicine recommendations. Additional analyses indicated that greater perceived PSFs were associated with meeting these recommendations among Whites but not among African Americans. 相似文献
102.
Philip Harber Laura Pea Paul Hsu Elizabeth Billet Deborah Greer Katty Kim 《American journal of industrial medicine》1994,25(4):519-526
Back pain among nurses is a common problem. Prior studies of this problem have been based on cross-sectional or retrospective data. This 18-month prospective study involving nurses newly graduated from nursing school investigated personal, worksite, and training factors associated with future risk of back pain. Each nurse underwent a preliminary interview and periodic follow-ups to identify those with back injuries. Contingency tables and logistic regression analyses demonstrated that prior significant back pain episodes (evidenced by previous job changes because of back pain, frequent medication use, etc.) were associated with increased future risk. Training at nursing school or on the job did not have a protective effect. This pilot study therefore suggests factors useful in placement and counseling of new nurses and indicates the need for further implementation of mechanical lift assist device use. © 1994 Wiley-Liss, Inc. 相似文献
103.
OBJECTIVE: To describe the rationale, methodology, and general sample characteristics of the Canadian Psychiatric Association (CPA) practice profile survey, a national survey of psychiatrists and psychiatric practice. METHOD: Mail-in interviews were sent to all Canadian psychiatrists listed in their provincial registers and to all active CPA members (total = 3628). Respondents provided general information about their professional activities for one 24-hour day and detailed information for 1 randomly selected hour. Patient information--including sociodemographics, diagnostic profiles, functioning levels, risk of harm to self or others, and disposition--was elicited for 1 patient seen during the random hour as well as for the most seriously ill patient receiving clinical services that day. RESULTS: There was a 45.5% response rate. Questionnaires completed by nonpsychiatrists or with a large percentage of missing or incorrect data were eliminated (107 surveys), resulting in a final sample size of 1570. CPA members and those from Western Canada responded at a higher rate to the survey. The results suggest some cause for concern about future manpower shortages. Most psychiatrists practise eclectically, seeing patients across the life-span, and working in both community and institutional settings. The old and the young appear to be underserviced, compared with adults. CONCLUSIONS: This study represents an important step forward in evaluating the profile and activities of the profession. 相似文献
104.
105.
Elizabeth Roberts Steven D Void Robert H Rosa David C Dries 《Ophthalmic surgery, lasers & imaging》2007,38(4):326-327
The presence of collateral vessels in a young child with glaucoma is rare. The authors describe a case of collateral vessel regression with intraocular pressure reduction in a child with primary congenital glaucoma. Six months following 180 degrees goniotomies in each eye, the intraocular pressure was reduced, dilation of the retinal arteries and veins resolved, and collateral vessels in both eyes regressed. Intraocular pressure reduction may lead to the regression of collateral vessels in children with primary congenital glaucoma. 相似文献
106.
Joseph C. Alper M.D. Elizabeth A. Welch M.D. Patricia Maguire R.N. 《Age (Dordrecht, Netherlands)》1986,9(4):105-109
During a five year period, approximately 150 elderly patients were treated with a water vapor and oxygen permeable membrane
(VPM) in an open fashion.
The following is important when treating elderly patients with VPM: xerosis or irritant dermatitis must be thoroughly treated
before use of VPM as it will not adhere to abnormal skin; alcohol or acetone should not be used to prepare the treatment site
as they cause irritation; VPM must not be stretched prior to placement as friction blisters occur in fragile, elderly skin;
prior to removal, VPM should be soaked in soapy water or its surface rubbed lightly with alconol to break the adhesive bond
to prevent stripping off epidermis; in patients with protein-calorie malnutrition, serum albumin should be monitored as large
amounts of protein-rich fluid collect under VPM. VPM is a useful non-surgical approach to treating many ulcers in the elderly.
Certain precautions must be taken to achieve optimum success in this population. 相似文献
107.
108.
Elizabeth Rosyold Russell Schilder Judy Walczak S. M. DiFino P. J. Flynn T. K. Banerjee W. J. Heim Paul E. Engstrom Robert F. Ozols Peter J. O'Dwyer 《Cancer chemotherapy and pharmacology》1992,29(4):305-308
Summary Phosphonacetyl-l-aspartate (PALA), an inhibitor of aspartate transcarbamylase that depletes uridine nucleotide pools, selectively potentiates the antitumor activity of 5-fluorouracil (5-FU) in preclinical models. Due to the promising results we obtained using PALA/5-FU in colorectal cancer, we performed a phase II trial in patients presenting with advanced pancreatic cancer. PALA was given intravenously at 250 mg/m2 on day 1, followed 24 h later by 2,600 mg/m2 5-FU given by 24-h infusion. Treatments were repeated weekly. A total of 41 patients who had not previously undergone chemotherapy were entered in the trial; of these, 35 were evaluable for response. Toxicity was generally mild to moderate; neurotoxicity (13/35) and diarrhea (8/35) predominated. Among the 35 patients, 1 achieved a complete response and 4, a partial remission, for an overall response rate of 14%. The median survival was 5.1 months. Pretreatment with PALA alone was not sufficient to enhance the activity of 5-FU in pancreatic cancer.Supported in part by grant CA 06927 from the National Cancer Institute 相似文献
109.
Elizabeth Shearer 《分娩》1998,25(2):138-138
110.
Lawrence H. Moulton Elizabeth A. Holt Jayakaran S. Job Neal A. Halsey 《Statistics in medicine》1995,14(8):777-787
Antibody responses following vaccination usually are analysed by comparing geometric mean concentrations across levels of relevant covariates and by comparing the proportions of vaccinees responding. In the regression setting, the analyses are done on log-transformed concentrations, estimating geometric mean responses conditional on a vector of covariates. More detailed analyses examining the relationship of covariates to different parts of the response distribution may be performed through the application of asymmetric least squares estimation of regression percentiles. We present a method for accounting for correlation in percentile regression analyses of longitudinal antibody response data. We illustrate the procedures with measles antibody response data from Haitian children who participated in a randomized trial of high titre vaccines. The strongest dose and strain effects were seen in the low end of the antibody concentration distributions. 相似文献