全文获取类型
收费全文 | 6246篇 |
免费 | 534篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 76篇 |
儿科学 | 226篇 |
妇产科学 | 145篇 |
基础医学 | 694篇 |
口腔科学 | 162篇 |
临床医学 | 735篇 |
内科学 | 1156篇 |
皮肤病学 | 93篇 |
神经病学 | 573篇 |
特种医学 | 292篇 |
外科学 | 913篇 |
综合类 | 152篇 |
一般理论 | 2篇 |
预防医学 | 740篇 |
眼科学 | 150篇 |
药学 | 350篇 |
中国医学 | 8篇 |
肿瘤学 | 337篇 |
出版年
2023年 | 65篇 |
2022年 | 99篇 |
2021年 | 234篇 |
2020年 | 105篇 |
2019年 | 174篇 |
2018年 | 196篇 |
2017年 | 145篇 |
2016年 | 138篇 |
2015年 | 178篇 |
2014年 | 207篇 |
2013年 | 275篇 |
2012年 | 330篇 |
2011年 | 328篇 |
2010年 | 190篇 |
2009年 | 188篇 |
2008年 | 279篇 |
2007年 | 273篇 |
2006年 | 218篇 |
2005年 | 234篇 |
2004年 | 219篇 |
2003年 | 195篇 |
2002年 | 158篇 |
2001年 | 137篇 |
2000年 | 167篇 |
1999年 | 125篇 |
1998年 | 94篇 |
1997年 | 68篇 |
1996年 | 80篇 |
1995年 | 55篇 |
1994年 | 81篇 |
1993年 | 63篇 |
1992年 | 88篇 |
1991年 | 96篇 |
1990年 | 85篇 |
1989年 | 93篇 |
1988年 | 92篇 |
1987年 | 74篇 |
1986年 | 76篇 |
1985年 | 59篇 |
1984年 | 57篇 |
1983年 | 65篇 |
1982年 | 56篇 |
1981年 | 43篇 |
1980年 | 48篇 |
1979年 | 58篇 |
1978年 | 57篇 |
1977年 | 39篇 |
1976年 | 32篇 |
1973年 | 32篇 |
1970年 | 30篇 |
排序方式: 共有6804条查询结果,搜索用时 15 毫秒
991.
A retrospective review of suicides occurring among Aboriginal people in the community in South Australia over a 5-year period was undertaken from January 2005 to December 2009. Twenty-eight cases were identified, consisting of 21 males (age range 16–44 years, mean 29.9 years) and 7 females (age range 23–45 years, mean 32.0 years). Deaths in all cases were caused by hanging (100%). Toxicological evaluation of blood revealed alcohol (39.3% of cases), cannabinoids (39.3%), benzodiazepines (10.7%), opiates (7.1%), antidepressants (7.1%), amphetamines (3.6%) and volatiles (3.6%). This study has demonstrated that the method of suicide overwhelmingly preferred by indigenous victims in South Australia is hanging. The precise reasons for this preference are uncertain, however, an indigenous person in South Australia presenting as a suicide where a method other than hanging has been used would be exceedingly uncommon, raising the possibility of alternative manners of death. 相似文献
992.
Review of 69 cases of lethal asphyxia in individuals aged from 10 to 18 years was undertaken in South Australia. There were 62 cases of suicide due to hanging (89.9%) (age range 10-18 years; mean?=?16.6 years; M:F?=?3.4:1), 4 accidents (5.8%) (3 crush asphyxias in motor vehicle rollovers, and 1 positional asphyxia associated with marked alcohol intoxication) and 3 homicides (4.3%). In the suicide group, there were 46 whites (74.2%), 12 Aboriginal (19.4%), 3 Asians (4.8%) and 1 African (1.6%). There were no deaths due to sexual asphyxia or the "choking game". However, the percentage of Aboriginal victims was disproportionately high compared to the percentage of the population aged 10-19 years listed as Aboriginal (approximately 3%). Thus, constant monitoring of local trends in mortality will identify if new activities such as the "choking game" have emerged, and also characterize specific problems that may exist in particular communities or cultural groups. 相似文献
993.
Sathiyaprakash Ramdoss Austin Mulloy Russell Lang Mark O’Reilly Jeff Sigafoos Giulio Lancioni Robert Didden Farah El Zein 《Research in autism spectrum disorders》2011,5(4):1306-1318
The purpose of this review is to provide a systematic analysis of studies investigating computer-based interventions (CBI) to improve literacy skills (e.g., reading, writing, and vocabulary) in students with autism spectrum disorders (ASD). This review synthesizes intervention outcomes, appraises the certainty of evidence, and describes software features and system requirements for each CBI. Across studies, CBI's effect on literacy skills was inconsistent. Some studies reported significant results and large effect sizes and other studies reported no improvements. Given the heterogeneity of the participants and the wide variety of literacy skills targeted for instruction, it is not possible from the existing literature to determine the variables most likely to be associated with effective CBI. Future research addressing this area as well as the relative effectiveness of CBI versus person delivered literacy instruction is warranted. 相似文献
994.
OBJECTIVE: Diagnostic imaging performed during pregnancy, particularly if it involves the use of ionizing radiation, can be a source of great anxiety for both health care providers and patients. Especially with the growing public awareness of the increasing radiation from medical imaging, including CT, it is important to have a contemporary policy for imaging evaluation in the pregnant or potentially pregnant patient. Implementation of such policies and guidelines would be useful for those developing or modifying policies for imaging pregnant or potentially pregnant patients; those developing regional or national guidelines or recommendations (i.e., professional specialty societies, including emergency medicine, radiology, and obstetrics and gynecology); and groups such as National Council on Radiation Protection, advocacy groups, and individuals writing research grants or articles. CONCLUSION: To this end, a compendium of resources representing national organization guidelines would be useful. The purpose of this study is to review available resources for pertinent recommendations that can be used to develop or update policies for imaging during pregnancy, as well as to serve as a reference document for preparing reports, scientific articles, or other documents by individuals or organizations, including regulatory agencies. 相似文献
995.
Rossoni LV Wareing M Wenceslau CF Al-Abri M Cobb C Austin C 《Clinical science (London, England : 1979)》2011,121(10):449-458
Statins can have beneficial cholesterol-independent effects on vascular contractility, which may involve increases in the bioavailability of NO (nitric oxide) as a result of phosphorylation of eNOS (endothelial NO synthase). Although this has been attributed to phosphorylation of Akt (also known as protein kinase B), studies in cultured cells have shown that statins can phosphorylate AMPK (AMP-activated protein kinase); it is unknown whether this has functional effects in intact arteries. Thus we investigated the acute effects of simvastatin on resistance arterial contractile function, evaluating the involvement of NO, Akt and AMPK. Isolated rat mesenteric resistance arteries were mounted on a wire myograph. The effects of incubation (1 and 2?h) with simvastatin (0.1 or 1?μM) on contractile responses were examined in the presence and absence of L-NNA (N-nitro-L-arginine; 10?μM) or mevalonate (1?mM). Effects on eNOS, phospho-eNOS (Ser1177), and total and phospho-Akt and -AMPK protein expression were investigated using Western blotting. The effect of AMPK inhibition (compound C, 10?μM) on eNOS phosphorylation and contractile responses were also studied. Simvastatin (1?μM, 2?h) significantly reduced constriction to U46619 and phenylephrine and enhanced dilations to ACh (acetylcholine) in depolarized, but not in U46619-pre-constricted arteries. These effects were completely and partially prevented by L-NNA and mevalonate respectively. Simvastatin increased eNOS and AMPKα phosphorylation, but had no effect on Akt protein expression and phosphorylation after 2?h incubation. Compound C prevented the effects of simvastatin on eNOS phosphorylation and contractility. Thus simvastain can acutely modulate resistance arterial contractile function via mechanisms that involve the AMPK/phospho-eNOS (Ser1177)/NO-dependent pathway. 相似文献
996.
997.
Azzam K Parvizi J Kaufman D Purtill JJ Sharkey PF Austin MS 《The Journal of arthroplasty》2011,26(8):1139-1144
Revision arthroplasty is often required for confirmed cases of symptomatic tibiofemoral instability after total knee arthroplasty (TKA). We evaluated the results of revision for TKA instability in a consecutive series of 67 patients (68 knees) between 2000 and 2006. Outcome measures were surgeon-based assessment of knee stability, Knee Society Score, and Short Form Health Survey 36. At an average of 39 months of follow-up, the mean Knee Society Score and Short Form Health Survey 36 physical and mental scores were 76, 53, and 67 points, respectively. Knee instability persisted in 14 patients (22%). Data at the 95% confidence level revealed that revising both the femoral and tibial components, the use of femoral augments, and smaller joint line elevation as measured on radiographs correlated significantly with achieving a stable knee. In revision surgery for TKA instability, revision of both components and the use of femoral augments seem to offer the most predictable outcome. 相似文献
998.
Kim HJ Fragomen AT Reinhardt K Hutson JJ Rozbruch SR 《Journal of orthopaedic trauma》2011,25(11):681-684
Leg length discrepancies can occur despite successful union of femur fractures after intramedullary nailing (IMN). Often, the leg length discrepancy can result in significant disability to the patient, altered gait biomechanics, pelvic obliquity, and pain. Therefore, a successful clinical result for such deformities after IMN involves addressing the leg length inequality. Femoral reconstruction with an osteotomy around an existing intramedullary nail was introduced to address axial deformity correction and limb lengthening without changing or removing a previously inserted IMN. This technique uses the principles of lengthening over an IMN. The presence of the nail has minimized the time needed for the external fixator because the nail supports the regenerate bone or osteotomy during the consolidation phase. With this technique, surgery is minimized by avoiding the need for exchange nailing. 相似文献
999.
A 67-year-old man presented with hemoptysis following 2 previous operations on the descending thoracic aorta. Preoperative investigations and surgical exploration failed to demonstrate an aortobronchial fistula. It was subsequently detected at autopsy after the patient succumbed to a massive bout of hemoptysis. 相似文献
1000.
Hankemeier S van Griensven M Ezechieli M Barkhausen T Austin M Jagodzinski M Meller R Bosch U Krettek C Zeichen J 《Archives of orthopaedic and trauma surgery》2007,127(9):815-821
Introduction The original complex structure and mechanical properties are not fully restored after ligament and tendon injuries. Due to
their high proliferation rate and differentiation potential, Bone Marrow Stromal Cells (BMSC) are considered to be an ideal
cell source for tissue engineering to optimize the healing process. Ideal matrices for tissue engineering of ligaments and
tendons should allow for homogenous cell seeding and offer sufficient stability.
Material and methods A mixture of human BMSC and liquid fibrin glue was injected into a standardized full-thickness window defect of the patellar
tendon of immunodeficient rats (BMSC group). The histology of the tissue was analysed 10 and 20 days postoperatively and compared
to four control groups. These groups consisted of a cohort with a mixture of human fibroblasts and fibrin glue, fibrin glue
without cells, a defect group without treatment, and a group with uninjured patellar tendon tissue.
Results Tendon defects in the BMSC group revealed dense collagen fibres and spindle-shaped cells, which were mainly orientated along
the loading axis. Histologic sections of the control groups, especially of untreated defects and of defects filled with fibrin
glue only, showed irregular patterns of cell distribution, irregular formed cell nucleoli and less tissue maturation. Compared
to healthy tendon tissue, higher numbers of cells and less intense matrix staining was observed in the BMSC group. No ectopic
bone or cartilage formation was observed in any specimen.
Conclusions Injection of human BMSC in a fibrin glue matrix appears to lead to more mature tissue formation with more regular patterns
of cell distribution. Advantages of this “in-vivo” tissue engineering approach are a homogenous cell-matrix mixture in a well-known
and approved biological matrix, and simple, minimally-invasive application by injection. 相似文献