全文获取类型
收费全文 | 9056篇 |
免费 | 654篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 187篇 |
妇产科学 | 185篇 |
基础医学 | 993篇 |
口腔科学 | 112篇 |
临床医学 | 1069篇 |
内科学 | 1659篇 |
皮肤病学 | 120篇 |
神经病学 | 792篇 |
特种医学 | 521篇 |
外国民族医学 | 1篇 |
外科学 | 1135篇 |
综合类 | 101篇 |
一般理论 | 8篇 |
预防医学 | 1149篇 |
眼科学 | 159篇 |
药学 | 609篇 |
中国医学 | 4篇 |
肿瘤学 | 858篇 |
出版年
2023年 | 33篇 |
2022年 | 73篇 |
2021年 | 160篇 |
2020年 | 87篇 |
2019年 | 165篇 |
2018年 | 212篇 |
2017年 | 143篇 |
2016年 | 142篇 |
2015年 | 186篇 |
2014年 | 270篇 |
2013年 | 484篇 |
2012年 | 654篇 |
2011年 | 678篇 |
2010年 | 388篇 |
2009年 | 366篇 |
2008年 | 605篇 |
2007年 | 590篇 |
2006年 | 559篇 |
2005年 | 578篇 |
2004年 | 564篇 |
2003年 | 602篇 |
2002年 | 501篇 |
2001年 | 112篇 |
2000年 | 107篇 |
1999年 | 116篇 |
1998年 | 107篇 |
1997年 | 70篇 |
1996年 | 60篇 |
1995年 | 51篇 |
1994年 | 41篇 |
1993年 | 47篇 |
1992年 | 66篇 |
1991年 | 61篇 |
1990年 | 68篇 |
1989年 | 59篇 |
1988年 | 66篇 |
1987年 | 62篇 |
1986年 | 38篇 |
1985年 | 56篇 |
1984年 | 50篇 |
1983年 | 45篇 |
1982年 | 28篇 |
1979年 | 30篇 |
1977年 | 21篇 |
1976年 | 24篇 |
1975年 | 22篇 |
1974年 | 22篇 |
1973年 | 32篇 |
1971年 | 27篇 |
1969年 | 19篇 |
排序方式: 共有9718条查询结果,搜索用时 31 毫秒
11.
Allergic autoimmune reaction after exposure to heavy metals such as mercury may play a causal role in autism, a developmental disorder of the central nervous system. As metallothionein (MT) is the primary metal-detoxifying protein in the body, we conducted a study of the MT protein and antibodies to metallothionein (anti-MT) in normal and autistic children whose exposure to mercury was only from thimerosal-containing vaccines. Laboratory analysis by immunoassays revealed that the serum level of MT did not significantly differ between normal and autistic children. Furthermore, autistic children harboured normal levels of anti-MT, including antibodies to isoform MT-I (anti-MT-I) and MT-II (anti-MT-II), without any significant difference between normal and autistic children. Our findings indicate that because autistic children have a normal profile of MT and anti-MT, the mercury-induced autoimmunity to MT may not be implicated in the pathogenesis of autism. 相似文献
12.
Sharon Craven Lori Dewar Xianjun Yang Jeff Ginsberg Frederick Ofosu 《Blood coagulation & fibrinolysis》2007,18(3):219-225
Up to 20% of patients develop venographically proven deep-vein thrombosis after elective orthopedic surgery even under the cover of heparin or low molecular weight heparin. The extent to which the chronic inflammation of osteoarthritis requiring elective orthopedic surgery alters in-vivo coagulation and whether any specific alteration influences the development of postoperative thrombosis are unknown. This study compared the concentrations of activated factor VII (FVIIa), tissue factor pathway inhibitor (TFPI), activated factor X (FXa)-TFPI, thrombin-antithrombin, and prothrombin fragment 1+2 (F1+2) in plasmas of 535 healthy individuals (ages 17-76) with those in the preoperative plasmas of 306 arthritis patients (ages 30-92) scheduled for elective knee or hip replacement surgery. C-reactive protein was also measured in the plasmas of approximately 15% of the participants. Age-adjusted concentrations of FVIIa, F1+2, and C-reactive protein were higher in patients than controls, while the concentrations of thrombin-antithrombin, TFPI and FXa-TFPI were similar. Chronic inflammation in the patients was thus associated with increased coagulation in vivo. Without compensatory increases in the concentrations of TFPI (natural inhibitor of prothrombinase), the elevated concentrations of FVIIa in the preoperative plasmas and the trauma associated with surgery may enhance the risk for developing postoperative deep-vein thrombosis. 相似文献
13.
C R Evian C B Ijsselmuiden G N Padayachee H S Hurwitz 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,78(9):517-520
In January 1989, the Johannesburg City Health Department developed an AIDS education poster. The poster was adapted from a cartoon in the Sowetan newspaper and was formally evaluated before its final production. As a result of this evaluation further editing and restructuring of the poster proved necessary. The methodology used in the evaluation is outlined, and some of the findings that emerged during the evaluation are discussed, since few formal evaluations of health education material seem to have been documented in South Africa. This study highlights the importance of formative evaluation of printed health educational media by a sample of the target audience before production and distribution. 相似文献
14.
15.
Miriam Stewart Linda Reutter Edward Makwarimba Irving Rootman Deanna Williamson Kim Raine Doug Wilson Janet Fast Rhonda Love Sharon McFall Deana Shorten Nicole Letourneau Karen Hayward Jeff Masuda William Rutakumwa 《Revue canadienne de recherche en sciences infirmières》2005,37(3):104-131
Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies. 相似文献
16.
The integration of disability management into the strategic planning of a corporation ensures a work environment is created that motivates employees to consistently meet customer expectations. Disability management strategies can achieve significant decreases to the human and financial cost of workers' compensation, sick leave or short term disability, and long-term disability. The business case for disability management including effective return to work programs clearly supports program implementation to enhance employee engagement, delivery of corporate priorities, and improvement to the company's bottom line. 相似文献
17.
Merritt W Brown Brenda E Porter Dennis J Dlugos Jeff Keating Andrew B Gardner Phillip B Storm Eric D Marsh 《Clinical neurophysiology》2007,118(8):1744-1752
OBJECTIVE: Interictal spikes in intracranial EEG (iEEG) may correlate with epileptogenic cortex, but review of interictal iEEG is labor intensive. Accurate automated spike detectors are necessary for understanding the role of spikes in epileptogenesis. METHODS: The sensitivity, accuracy and reproducibility of three automated iEEG spike detectors were compared against two human EEG readers using iEEG segments from eight patients. A consensus set of detections was generated for detector calibration. Spike verification was calculated after both human EEG readers independently reviewed all detections. RESULTS: Humans and two of the three automated detectors demonstrated comparable accuracy. In four patients, automated spike detection sensitivity was >70% and accuracy was >50%. In the remaining four patients, EEG background morphology resulted in poorer performance. Blinded human verification accuracy was 76.7+/-6.6% for computer-detected spikes, and 84.5+/-4.1% for human-detected spikes. CONCLUSIONS: Automated iEEG spike detectors perform comparably to humans, but sensitivity and accuracy are patient dependent. Humans verified the majority of computer-detected spikes. SIGNIFICANCE: In some patients automated detectors may be used for mapping spike occurrences in epileptic networks. This may reveal associations between spike distribution, seizure onset, and pathology. 相似文献
18.
19.
Renal uptake of Tl-201 reflects renal perfusion and may have a role in defining renal asymmetry in patients with hypertension who are referred for myocardial scintigraphy. The authors compared two methods of quantitating differential renal uptake of Tl-201, with similar data obtained from the angiographic and renal uptake (RU) phases of Tc-99m DTPA scintigraphy in 35 patients with hypertension. For Tl-201, asymmetry in renal counts was quantitated based on a simple outline technique or on interpolative background subtraction of 5-minute posterior images. Inter-observer and intra-observer variability among duplicate measurements were lower for Tl-201, particularly with interpolative background subtraction, than for Tc-99m DTPA. Renal/background ratios were similar for Tl-201 and RU-phase Tc-99m DTPA images when considering liver, spleen, or inter-renal regions as background; however, paraspinal uptake was relatively higher with Tl-201 (P less than 0.01). Qualitatively, renal asymmetry scores with the two radiotracers agreed (r = 0.89, blinded readings by four observers), although asymmetry was more marked with Tl-201 (P = 0.06). Measurements with Tl-201 agreed with both phases of Tc-99m DTPA (r = 0.96 to 0.98), but interpolative background subtraction systematically yielded greater inter-renal asymmetry than RU (P less than 0.01), reflecting the qualitative impression. Thus, ancillary Tl-201 imaging reflects differences between the kidneys in a fashion similar but not identical to Tc-99m DTPA scintigraphy. 相似文献
20.
Roscoe Taylor Jeff Bazelmans Robert Golec Simon Oakes 《Australian and New Zealand journal of public health》1995,19(5):455-459
Abstract: To investigate the distribution of blood lead levels in a sample of Victorian children, and to compare current levels with those from a similar survey in 1979, blood was tested for lead in 252 children (123 under five years) attending Royal Children's Hospital as outpatients and having venepuncture blood samples for medical reasons. Blood lead levels were determined by graphite furnace atomic absorption spectrophotometer. The mean blood lead level was 0.26 μmol/L (5.4 μg/dL). In the under-five age group, the mean was 0.28 μmol/L (5.7 μg/dL). Only 1.6 per cent of this group exceeded the National Health and Medical Research Council action level of 0.72 μmol/L (15 μg/dL). Levels in this age group have declined significantly since 1979, when the mean was 0.54 μmol/L (11.1 μg/dL) and 12.9 per cent exceeded 0.72 μmol/L (15 μg/dL). Average blood lead levels have halved since 1979, with likely contributing factors being reduced exposure from lead in diet, reduced access to lead in paint and reduced lead in ambient air. Children with elevated levels had identifiable risk factors such as pica or exposure to lead-based paint, suggesting the need for ongoing public health action to prevent exposure in these groups. 相似文献