全文获取类型
收费全文 | 18332篇 |
免费 | 1703篇 |
国内免费 | 80篇 |
专业分类
耳鼻咽喉 | 118篇 |
儿科学 | 612篇 |
妇产科学 | 471篇 |
基础医学 | 2775篇 |
口腔科学 | 371篇 |
临床医学 | 1950篇 |
内科学 | 4005篇 |
皮肤病学 | 400篇 |
神经病学 | 1922篇 |
特种医学 | 509篇 |
外科学 | 1925篇 |
综合类 | 300篇 |
现状与发展 | 1篇 |
一般理论 | 17篇 |
预防医学 | 1781篇 |
眼科学 | 316篇 |
药学 | 1203篇 |
中国医学 | 40篇 |
肿瘤学 | 1399篇 |
出版年
2023年 | 240篇 |
2022年 | 450篇 |
2021年 | 857篇 |
2020年 | 466篇 |
2019年 | 699篇 |
2018年 | 703篇 |
2017年 | 518篇 |
2016年 | 545篇 |
2015年 | 562篇 |
2014年 | 743篇 |
2013年 | 915篇 |
2012年 | 1319篇 |
2011年 | 1385篇 |
2010年 | 734篇 |
2009年 | 655篇 |
2008年 | 935篇 |
2007年 | 1020篇 |
2006年 | 926篇 |
2005年 | 876篇 |
2004年 | 828篇 |
2003年 | 766篇 |
2002年 | 711篇 |
2001年 | 272篇 |
2000年 | 248篇 |
1999年 | 228篇 |
1998年 | 135篇 |
1997年 | 125篇 |
1996年 | 94篇 |
1995年 | 83篇 |
1994年 | 80篇 |
1993年 | 91篇 |
1992年 | 118篇 |
1991年 | 137篇 |
1990年 | 153篇 |
1989年 | 134篇 |
1988年 | 134篇 |
1987年 | 126篇 |
1986年 | 112篇 |
1985年 | 97篇 |
1984年 | 87篇 |
1983年 | 81篇 |
1982年 | 54篇 |
1981年 | 51篇 |
1980年 | 46篇 |
1979年 | 64篇 |
1978年 | 57篇 |
1977年 | 48篇 |
1975年 | 35篇 |
1974年 | 42篇 |
1972年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Emma J. Walker Noni E. MacDonald Nehal Islam Nicole Le Saux Karina A. Top Deshayne B. Fell 《Vaccine》2019,37(13):1725-1735
Objective
To systematically review literature on uptake and timeliness of diphtheria-tetanus-pertussis, measles-mumps-rubella, and/or polio-containing vaccines in infants who were born preterm, with a low birth weight, and/or with chronic health conditions that were diagnosed within the first 6?months of life.Methods
Using a standardized search strategy developed by a medical librarian, records were extracted from MEDLINE, Embase, Database of Abstracts of Reviews of Effects, and CINAHL up to May 8, 2018.Results
Out of the 1997 records that were screened, we identified 21 studies that met inclusion criteria. Eleven studies assessed vaccine coverage and/or timeliness in preterm infants, 6 in low birth weight infants, and 7 in children with chronic health conditions. Estimates of coverage in these populations were highly variable, ranging from 40% to 100% across the vaccines and population groups.Conclusions
There is a lack of studies reporting coverage and timeliness of routine immunizations in special populations of children.Policy implications
Our review suggests a need for improved surveillance of immunization status in special populations of infants, as well as a need for standardization of reporting practices. 相似文献12.
13.
Miguel A. Sanz Pau Montesinos Haesook T. Kim Guillermo J. Ruiz-Argüelles María S. Undurraga María R. Uriarte Lem Martínez Rafael H. Jacomo Homero Gutiérrez-Aguirre Raul A. M. Melo Rosane Bittencourt Ricardo Pasquini Katia Pagnano Evandro M. Fagundes Edo Vellenga Alexandra Holowiecka Ana J. González-Huerta Pascual Fernández Javier De la Serna Salut Brunet Elena De Lisa José González-Campos José M. Ribera Isabel Krsnik Arnold Ganser Nancy Berliner Raul C. Ribeiro Francesco Lo-Coco Bob L?wenberg Eduardo M. Rego 《Annals of hematology》2015,94(8):1347-1356
14.
Stephanie A. Grilo Marina Catallozzi John S. Santelli Hanying Yan Xiaoyu Song Jennifer Heitel Kristen Kaseeska Julie Gorzkowski Alexandra E. Dereix Jonathan D. Klein 《The Journal of adolescent health》2019,64(3):311-318
Purpose
The objective of the study was to define factors associated with adolescent and young adult (AYA) experiences with private time and having discussed confidentiality and the impact of these experiences on improving delivery of clinical preventive services.Methods
In 2016, a nationally representative sample of 1,918 US AYAs (13- to 26-year-olds) was surveyed. Survey questionnaire domains were based on prior research and Fishers' information-motivation-behavior skills conceptual model. Data were weighted to represent US households with AYA and analyzed to identify factors independently associated with ever experiencing private time and discussions of confidentiality with a regular health-care provider (HCP). We examined the association of these experiences on AYA attitudes about health care.Results
Fifty-five percent of female and 49% of male AYA reported ever having had private time with an HCP and 55% of female and 44% of male AYA had spoken to an HCP about confidentiality. Independent predictors of having experienced private time and confidentiality included older age, race, higher household income, gender of the provider, amount of years with the provider, and involvement in risk behaviors. AYA who had experienced private time and confidentiality discussions had more positive attitudes about their providers, were more willing and comfortable discussing sensitive topics, and thought that these discussions should happen at younger ages.Conclusions
Although confidentiality and private time are important to AYA, many are not experiencing these components of care. Providing private time and discussions of confidentiality can improve the delivery of health care for young people by enhancing positive youth attitudes about preventive care. 相似文献15.
The vagal nerve as a link between the nervous and immune system in the instance of polymicrobial sepsis 总被引:5,自引:0,他引:5
Wolfram Kessler Tobias Traeger Alexandra Westerholt Friederike Neher Marlene Mikulcak Antje Müller Stefan Maier Claus-Dieter Heidecke 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》2006,391(2):83-87
Background The role of the vagal nerve in the autonomic nervous system is widely well known. Recently, an additional function was revealed
serving as a connector between the nervous and immune system. This connection is called the “cholinergic inflammatory pathway.”
Through stimulation of the acetylcholine receptors located upon the macrophages, the “unspecific” immune system can be directly
influenced.
Methods The vagal nerve was completely transected directly posterior to its passage through the diaphragm. The effect of complete
vagotomy was analyzed using a murine model of polymicrobial peritonitis (colon ascendens stent peritonitis, CASP). Survival
and clinical course of vagotomized or sham-operated mice were analyzed in the CASP model.
Results After CASP surgery, vagotomy led to a significantly increased mortality (64.7%) in comparison to sham-vagotomized animals
(34%). No difference in the bacterial load of various tissues (lung, liver, spleen, blood, lavage fluid, and kidney) from
septic animals with or without vagotomy was observed. Vagotomized animals reveal elevated serum cytokine levels (TNF, IL-6,
IL-10, and MCP-1) 20 h after the induction of polymicrobial peritonitis.
Conclusion The vagal nerve is therefore an important modulator of the immune system.
W. Kessler and T. Traeger contributed equally to this work
Best of Forum Papers presented at the Annual Meeting of the German Society of Surgery, 2–5 May 2006, Berlin, Germany 相似文献
16.
Spleen sizing by ultrasound in polycythaemia and thrombocythaemia: comparison with SPECT 总被引:3,自引:1,他引:2
M. Messinezy L. M. MacDonald T. O. Nunan N. B. Westwood S. Chinn & T. C. Pearson 《British journal of haematology》1997,98(1):103-107
Detection of non-palpable early splenic enlargement may aid diagnosis of primary polycythaemia (PP) and primary thrombocythaemia (PT). In this study linear spleen sizing by ultrasound has been compared with spleen volume estimation by single photon emission computerized tomography (SPECT) in 26 patients. Spleen length by ultrasound correlated well with SPECT volume estimation.
Ultrasound spleen length was also measured in 60 normal control subjects where the upper limit of the 95% reference range was 11.6 cm. Changes in spleen length with both age and body weight were substantial and overshadowed the imperfect reproducibility of this method. Therefore, interpretation of an individual's measured spleen length should be in relation to that predicted for adults of the same age and weight, particularly at the extremes of the younger, heavier patients and also the older, lighter patients.
Ultrasound spleen lengths of different patient groups (21 PP, 26 PT, 17 idiopathic erythrocytosis, 12 secondary polycythaemia, nine apparent polycythaemia) were compared both using the measured overall reference range and the differences from the values predicted for their age and weight. The comparison showed that almost all patients with PP whose spleens were not palpable had spleen lengths greater than the upper limit for the normal control group, but separation from the other patient groups was incomplete.
Detection of non-palpable splenomegaly by ultrasound length should remain a 'minor' criterion amongst the 'proposed modified diagnostic criteria' of PP. 相似文献
Ultrasound spleen length was also measured in 60 normal control subjects where the upper limit of the 95% reference range was 11.6 cm. Changes in spleen length with both age and body weight were substantial and overshadowed the imperfect reproducibility of this method. Therefore, interpretation of an individual's measured spleen length should be in relation to that predicted for adults of the same age and weight, particularly at the extremes of the younger, heavier patients and also the older, lighter patients.
Ultrasound spleen lengths of different patient groups (21 PP, 26 PT, 17 idiopathic erythrocytosis, 12 secondary polycythaemia, nine apparent polycythaemia) were compared both using the measured overall reference range and the differences from the values predicted for their age and weight. The comparison showed that almost all patients with PP whose spleens were not palpable had spleen lengths greater than the upper limit for the normal control group, but separation from the other patient groups was incomplete.
Detection of non-palpable splenomegaly by ultrasound length should remain a 'minor' criterion amongst the 'proposed modified diagnostic criteria' of PP. 相似文献
17.
18.
19.
Stent fracture: an unusual cause of late restenosis after sirolimus-eluting stent placement. 总被引:1,自引:0,他引:1
Anderson Mehrle Thomas Skelton Alexandra Almonacid 《Catheterization and cardiovascular interventions》2007,69(7):988-991
Stent fracture is uncommon but may have consequences including restenosis. To date, stent fractures reported have been related to aggressive post dilation. We describe a case that involves fracture of a stent deployed to nominal pressure. Unlike most stent fractures reported that involve stent struts only our case demonstrated circumferential disruption with complete separation of the stent segments. 相似文献
20.
Margaret MacDonald Matthew Law John Kaldor Jim Hales Gregory J. Dore 《The International journal on drug policy》2003,14(5-6):353
Objective: To examine the effectiveness of needle and syringe programmes (NSPs) in preventing HIV transmission among injecting drug users (IDUs).Methods: An ecological study design was used to determine change in HIV prevalence among injecting drug users between cities with and without NSPs. Several data sources, such as electronic journal databases, surveillance reports, websites, and index review of relevant journals, were used to identify studies of HIV seroprevalence among IDUs, and presence of NSPs. The rate of change in HIV prevalence was estimated by regression analysis.Results: There were 778 years of data from 99 cities globally included in the analysis. HIV prevalence decreased by 18.6% per annum in cities that introduce NSPs, and increased by 8.1% in cities that had never introduced NSPs (mean difference −24.7% [95% CI: −43.8, 0.5%], P=0.06). The mean difference was –33% when comparison was weighted to one over the variance of the regression estimator (29% decrease in cities with NSPs and 5% increase in cities without NSPs, P<0.001). When analysis was restricted to cities with first HIV seroprevalence less than 10%, the average annual change in seroprevalence was 18% lower in cities with NSPs (P=0.03).Conclusions: Despite the inherent limitations within an ecological study design, the study provides additional evidence that NSPs reduce transmission of HIV infection. The rapid spread of HIV among IDU populations and increasing rates of injecting in many countries calls for scaling up of NSPs as well as other harm reduction strategies. 相似文献