全文获取类型
收费全文 | 1471篇 |
免费 | 73篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 36篇 |
妇产科学 | 138篇 |
基础医学 | 187篇 |
口腔科学 | 27篇 |
临床医学 | 141篇 |
内科学 | 426篇 |
皮肤病学 | 31篇 |
神经病学 | 51篇 |
特种医学 | 116篇 |
外科学 | 127篇 |
综合类 | 15篇 |
一般理论 | 1篇 |
预防医学 | 118篇 |
眼科学 | 13篇 |
药学 | 67篇 |
中国医学 | 1篇 |
肿瘤学 | 53篇 |
出版年
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 25篇 |
2020年 | 25篇 |
2019年 | 32篇 |
2018年 | 25篇 |
2017年 | 19篇 |
2016年 | 27篇 |
2015年 | 30篇 |
2014年 | 41篇 |
2013年 | 67篇 |
2012年 | 57篇 |
2011年 | 67篇 |
2010年 | 59篇 |
2009年 | 41篇 |
2008年 | 72篇 |
2007年 | 86篇 |
2006年 | 77篇 |
2005年 | 89篇 |
2004年 | 55篇 |
2003年 | 50篇 |
2002年 | 40篇 |
2001年 | 28篇 |
2000年 | 23篇 |
1999年 | 27篇 |
1998年 | 25篇 |
1997年 | 31篇 |
1996年 | 21篇 |
1995年 | 15篇 |
1994年 | 23篇 |
1993年 | 14篇 |
1992年 | 33篇 |
1991年 | 29篇 |
1990年 | 17篇 |
1989年 | 29篇 |
1988年 | 25篇 |
1987年 | 24篇 |
1986年 | 26篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 18篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 13篇 |
1978年 | 6篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1975年 | 15篇 |
1974年 | 8篇 |
排序方式: 共有1554条查询结果,搜索用时 15 毫秒
1.
2.
To evaluate the correlation between persistent symptoms while stents are in place and final outcome in children with nasolacrimal duct obstruction (NLDO). A retrospective observational case series, with medical record review that included indications for surgery, surgical procedure, presence of symptoms while stents were in place, and final outcome after stent removal. Twenty-eight children with NLDO had nasolacrimal duct stents placed in 42 eyes. Twenty-one of the 42 eyes (50%) had minimal or no signs or symptoms of NLDO while stents were in place, and 18 of 21 (86%) were symptom-free after stent removal. Twenty-one of the 42 eyes (50%) remained symptomatic while stents were in place. Eleven of these 21 eyes (52%) had good outcomes after stent removal. Ten (48%) of these patients had persistent symptoms after stent removal requiring further treatment. The prognosis for a good outcome is excellent if symptoms of NLDO resolve while stents are in place. The prognosis is poorer if symptoms of NLDO persist, but more than half of such patients still have good outcomes. Careful counseling of parents regarding these outcomes should be performed before considering additional interventions. 相似文献
3.
4.
ALBERTO Q FARIAS LUCIANA L GONÇALVES EDUARDO LR CANÇADO ANTONIO C SEGURO SILVIA B CAMPOS CLARICE P ABRANTES-LEMOS FLAIR J CARRILHO 《Journal of gastroenterology and hepatology》2006,20(1):147-152
Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients. 相似文献
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients. 相似文献
5.
6.
7.
8.
Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm). 相似文献
9.
Reduction of epidural fibrosis in lumbar surgery with Oxiplex adhesion barriers of carboxymethylcellulose and polyethylene oxide. 总被引:5,自引:0,他引:5
Kathleen E Rodgers James T Robertson Theresa Espinoza Wilham Oppelt Stephanie Cortese Gere S diZerega Richard A Berg 《The spine journal》2003,3(4):277-83; discussion 284
BACKGROUND CONTEXT: Postsurgical epidural adhesions and fibrosis after surgery for lumbar disc herniation are a consequence of normal wound healing. The presence of fibrosis renders reoperations risky, and in some patients fibrosis may lead to nerve root tethering. PURPOSE: One approach to minimizing the risk of developing epidural adhesions is to provide a barrier between the dural membrane and the healing connective tissues. The purpose of these studies was to evaluate such a barrier device. STUDY DESIGN/SETTING: In vivo investigation in an animal model at a university laboratory. PATIENT SAMPLE: Rabbit. OUTCOME MEASURES: Gross and histomorphic evaluation. METHODS: Barriers comprised of carboxymethylcellulose (CMC) and polyethylene oxide (PEO) (Oxiplex; FzioMed, Inc., San Luis Obispo, CA) were studied as devices to reduce epidural adhesion formation in rabbit laminotomy and laminectomy models. The barriers tested were either a gel alone (gel) or a gel covered with a film (gel/film combination). Two laminotomy or laminectomy sites (depending on the surgical method) were created in each rabbit at L4 and L6. One site was treated with a CMC/PEO gel, or CMC/PEO gel/film combination, and the other site served as a surgical control. Two surgical models that differed in the extent of adhesion formation at untreated injury sites and the method of injury generation were used. RESULTS: Model A, which did not incorporate dural abrasion, resulted in up to 40% adhesion-free laminectomy sites in controls. Model B, which did incorporate abrasion of the dural membrane, resulted in less than 10% adhesion-free laminotomy sites in controls. Compositions of CMC/PEO gels (2.5% to 10% PEO) and films (22.5% PEO) were tested in both models. Efficacy parameters included measuring the number of sites free of epidural fibrosis and reduction in the severity of fibrosis (adhesions). Both gels and gel/film combinations consistently reduced the frequency and the extent of epidural fibrosis in both models. Gels of CMC/PEO containing a higher content of PEO (10%) and a higher molecular weight of PEO (4.4 mD) were most effective in Model B and resulted in up to 84% laminotomy sites with minimal or no epidural fibrosis, whereas controls exhibited over 90% of the sites with epidural fibrosis. Histological evaluation of the surgical sites indicated that the reduction of epidural fibrosis was accompanied by normal bone healing. In addition, these experiments demonstrated that the gel/film combination provided no additional benefit to that obtained by the gel alone. CONCLUSIONS: Gels of CMC/PEO reduced epidural fibrosis and did not impair normal heal ing. 相似文献
10.
Csar O. García A. Kanbour-Shakir Hua Tang Jos F. Molina Luis R. Espinoza Azzudin E. Gharavi 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(1):118-124
PROBLEM: Immunization with β2-glycoprotein I (β2GPI) induces antiphospholipid antibodies (aPL) in normal mice and rabbits. Recently we reported early onset of autoimmunity in MRL/++ mice following immunization with β2GPI. There is a close association between aPL with thrombosis, recurrent fetal loss, and intrauterine growth retardation. In this study we evaluated the effect of β2GPI-induced aPL on pregnancy outcomes in an inbred strain of mice (PL/J). METHOD: Three groups of seven-week-old female PL/J mice (12 per group) were studied. Group A was immunized with β2GPI and group B with ovalbumin; group C was not immunized. After two booster injections, the mice were tested for aPL, anti-DNA by ELISA, and for ANA by indirect immunofluorescence. Platelet count and pregnancy outcomes were studied at the age of 14 weeks. RESULTS: The aPL and anti-DNA levels were higher at 12 and 14 weeks in group A; the optical densities (OD) were 1.72±0.6 and 0.699±0.25 for group A, 0.091 ±0.040 and 0.230±0.47 for group B, and 0.0435±0.003 and 0.119±0.026 for group C (comparing group A with groups B and C combined, P<0.001). ANA titers rose in groups A and B by age, but they were significantly higher at 14 weeks in group A. The mean titers were 1/286, 1/90, and 1/16 for A, B, and C, respectively (P<0.001). The platelet counts were not significantly different among the three groups. The litter size was significantly smaller in group A, as evidenced by the numbers of viable fetuses among the mice that became pregnant in each group: 0.75, 2.45, and 5.5 in groups A, B, and C, respectively. Seven pregnant mice in group A had complete resorption, seven pregnant mice in group B showed focal (partial) resorption areas, and only one mouse in group C had complete resorption of the embryos, as shown by histopathological studies, although the fecundity rate was similar in the three groups. CONCLUSION: Our data suggest a pathogenic role for β2GPI-induced aPL in the development of experimental models of APS in PL/J mice. 相似文献