全文获取类型
收费全文 | 9446篇 |
免费 | 673篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 124篇 |
儿科学 | 293篇 |
妇产科学 | 265篇 |
基础医学 | 1554篇 |
口腔科学 | 287篇 |
临床医学 | 942篇 |
内科学 | 1965篇 |
皮肤病学 | 223篇 |
神经病学 | 795篇 |
特种医学 | 268篇 |
外科学 | 915篇 |
综合类 | 75篇 |
一般理论 | 5篇 |
预防医学 | 999篇 |
眼科学 | 124篇 |
药学 | 610篇 |
中国医学 | 14篇 |
肿瘤学 | 694篇 |
出版年
2023年 | 68篇 |
2022年 | 128篇 |
2021年 | 309篇 |
2020年 | 178篇 |
2019年 | 254篇 |
2018年 | 269篇 |
2017年 | 231篇 |
2016年 | 243篇 |
2015年 | 264篇 |
2014年 | 302篇 |
2013年 | 463篇 |
2012年 | 733篇 |
2011年 | 700篇 |
2010年 | 399篇 |
2009年 | 335篇 |
2008年 | 622篇 |
2007年 | 646篇 |
2006年 | 559篇 |
2005年 | 591篇 |
2004年 | 473篇 |
2003年 | 438篇 |
2002年 | 382篇 |
2001年 | 108篇 |
2000年 | 98篇 |
1999年 | 103篇 |
1998年 | 70篇 |
1997年 | 65篇 |
1996年 | 58篇 |
1995年 | 54篇 |
1994年 | 50篇 |
1993年 | 52篇 |
1992年 | 74篇 |
1991年 | 66篇 |
1990年 | 60篇 |
1989年 | 48篇 |
1988年 | 54篇 |
1987年 | 45篇 |
1986年 | 40篇 |
1985年 | 39篇 |
1984年 | 30篇 |
1983年 | 27篇 |
1980年 | 28篇 |
1979年 | 28篇 |
1978年 | 25篇 |
1976年 | 21篇 |
1975年 | 20篇 |
1974年 | 24篇 |
1973年 | 25篇 |
1972年 | 24篇 |
1971年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
21.
The malondialdehyde (MDA) content of cervical mucus from 23 healthy adult females was measured using an ion-pairing HPLC method capable of detecting 10 pmol MDA. Ten of the women were wearing copper IUDs, four were wearing plastic IUDs, and nine controls were not wearing an IUD. Cervical mucus was sampled during the follicular, periovulatory, luteal, and menstrual phases. The study was designed to determine if there is a relationship between MDA formation and the use of a copper IUD. A total of 79 samples were analyzed. Only 16 of the samples had sufficient MDA for reliable quantitation with the level ranging from 0.1 nmol/g to 2.32 nmol/g. In 19 of the samples, trace levels (less than 0.06 nmol/g) were detected but could not be reliably quantitated. In the remaining 44 samples, no MDA was detectable. There was no correlation between the presence of copper- or non-copper-containing IUDs and the level of MDA. These results are contrary to a previously published report that used a less specific method for MDA analysis. 相似文献
22.
23.
BACKGROUND: We reviewed the publication record of all protocols submitted to the Capital District Health Authority Research Ethics Board (REB) in Halifax, Nova Scotia, for the period 1995-1996. Because of a heightened awareness of the issue, we hypothesized that there would be less publication bias (a failure to report negative results) and a higher publication rate from completed studies, than previously reported. METHODS: Closed studies were identified from the REB database. Publications were identified by the investigators, requests from sponsors, and a literature review. For each publication, we identified authors, title, journal, number of subjects enrolled, and whether or not the publication was a report of a randomized clinical trial. Comparisons were done using a Student's t test, the Chi-square statistic, or Fisher's exact test as appropriate. RESULTS: From the database of closed studies, 106 remained unpublished, while completed investigations resulted in 84 publications (44% publication rate). The median time to publication was 32.5 months. Publication of statistically significant results occurred in 71/84 trials. Publication of protocols submitted by departments ranged from 91% (anesthesia; 10/11) to 25% [nursing; 2/8 (P<0.05)]. Trials investigating new drugs in Phase 3 or 4 studies were more likely to be published than trials investigating agents in Phase 1 or 2 (P<0.05), and were less likely to be published if sponsored by a pharmaceutical company (P<0.05). CONCLUSIONS: Publication bias continues to be a problem, particularly for early phase investigative studies. Our results suggest that a different approach is required to reduce publication bias. The role that REBs and peer-reviewed journals might play requires further exploration. 相似文献
24.
Noah Simmons Ognjen Brborovic Tozija Fimka Brian D Robie David L Bull Mome Spasovski Edward L Baker 《JPHMP》2005,11(4):351-356
The political disintegration of former Yugoslavia inaugurated in 1991 resulted in the decentralization of health systems in the federation's successor nation-states. Efforts by the Open Society Institute improved public health planning and management needs consequent to health sector changes. Beginning in Croatia in 2001, the Institute developed ongoing collaborations between Andrija Stampar School of Public Health and the US Centers for Disease Control and Prevention. In 2003 and 2004, it expanded its project to include the republics of Macedonia and of Serbia and Montenegro. 相似文献
25.
Andrew Edwards Anthony M. J. Bull Andrew A. Amis 《Knee surgery, sports traumatology, arthroscopy》2007,15(12):1414-1421
The tibial attachments of the individual anteromedial (AM) and posterolateral (PL) fibre bundles and the entire attachment
of the anterior cruciate ligament are described, relating them to consistent bony landmarks; 55 fresh-frozen specimens were
measured. The fibre bundles were separated and excised at their attachments and their peripheries marked with a pen. High-resolution
scaled digital photographs were taken of each dissected specimen and transferred onto a computer for analysis. A wide variation
was found when using the posterior tibial axis, the anterior tibial surface and the medial tibial spine as reference points.
The most consistent measurements used the tibial interspinous “over-the-back” ridge as a datum. The attachments of the PL
and AM bundles were centred 10 ± 1 mm (mean ± SD) and 17 ± 2 mm anterior to the over-the-back ridge. They were 4 ± 1 and 5 ± 1 mm,
respectively, lateral to the medial tibial spine border. The positions of 6 mm circles in the posterior-medial limits of the
fibre bundles (representing tunnels in a double-tunnel reconstruction) were measured. The overall dimensions of the tibial
plateaux correlated significantly with many measurements. The results from this study could be used to guide ACL reconstruction
techniques. 相似文献
26.
Michael S. Exton Diane F. Bull Maurice G. King Alan J. Husband 《Pharmacology, biochemistry, and behavior》1995,50(4):675-679
The cascade of physiologic mechanisms in response to infection, the acute-phase response, is recognized as playing a major role in host defence. One such response is the hypoferremia that is consistently reported to occur during bacterial infection. This study aimed to determine whether the alterations in plasma iron were conditionable using the conditioned taste aversion (CTA) paradigm. The regime involved the pairing of a novel-tasting saccharin solution with bacterial endotoxin. Seven days after the initial pairing of these stimuli (the test day), the saccharin solution was represented. Animals exposed to this condition displayed a significant reduction in the level of plasma iron. Animals treated with an intraperitoneal dose of 400 μg/Kg lipopolysaccharide (LPS) displayed lower conditioned iron levels than rats infused with 100 μg/Kg LPS; however, this difference was not significant. These results showed that in addition to other acute-phase responses (fever and anorexia), plasma iron alterations are able to be manipulated through behavioral manipulations. 相似文献
27.
Adrià Arboix Lluis García-Eroles Emili Comes Montserrat Oliveres Miquel Balcells Gustavo Pacheco Cecilia Targa 《European journal of neurology》2003,10(4):429-435
We assessed predictors of spontaneous early neurological recovery after acute ischemic stroke by means of multivariate analysis in a cohort of 1,473 consecutive patients treated at one academic center. At hospital discharge, spontaneous neurological improvement or good outcome was defined as grades 0-2 of the Rankin scale, and poor outcome (no improvement or in-hospital death) as grades 3-5. Spontaneous recovery of neurological deficit at the time of discharge from the hospital was observed in 16% of patients with cerebral infarction (n = 238). Dysarthria-clumsy hand syndrome improved in 44% of patients and was the only variable significantly associated with in-hospital functional recovery in three logistic regression models that in addition to lacunar syndromes, included demographic variables, cardiovascular risk factors, and clinical variables [odds ratio (OR) 2.56], neuroimaging findings (OR 2.48), and outcome data (OR 2.39), respectively. Clinical factors related to severity of infarction available at stroke onset have a predominant influence upon in-hospital outcome and may help clinicians to assess prognosis more accurately. Our work gives a contribution into prognostic factors after acute ischemic stroke. With regard to patterns of stroke, dysarthria-clumsy hand syndrome was a significant predictor of spontaneous in-hospital recovery in ischemic stroke patients. 相似文献
28.
Sheana Salyers Bull Cynthia Gillette Russell E Glasgow Paul Estabrooks 《Health education & behavior》2003,30(5):537-549
Information on external validity of work site health promotion research is essential to translate research findings to practice. The authors provide a literature review of work site health behavior interventions. Using the RE-AIM framework, they summarize characteristics and results of these studies to document reporting of intervention reach, adoption, implementation, and maintenance. The authors reviewed a total of 24 publications from 11 leading health behavior journals. They found that participation rates among eligible employees were reported in 87.5% of studies; only 25% of studies reported on intervention adoption. Data on characteristics of participants versus nonparticipants were reported in fewer than 10% of studies. Implementation data were reported in 12.5% of the studies. Only 8% of studies reported any type of maintenance data. Stronger emphasis is needed on representativeness of employees, work site settings studied, and longer term results. Examples of how this can be done are provided. 相似文献
29.
A R Bull 《Public health》1992,106(5):397-399
Medical audit is based on a cyclical model which is ideally suited to operational work that is (1) regularly repeated in similar situations; (2) clearly and directly linked to outcomes; (3) amenable to criteria of quality. The work of public health physicians is both operational (e.g. investigation of outbreaks of communicable disease) and strategic (e.g. health needs assessment). A cyclical model is not appropriate to strategic activity. Evaluation of that activity is essential--but should not be constrained/limited by inappropriate adherence to the audit cycle. 相似文献
30.