全文获取类型
收费全文 | 1334310篇 |
免费 | 95817篇 |
国内免费 | 2904篇 |
专业分类
耳鼻咽喉 | 19713篇 |
儿科学 | 40236篇 |
妇产科学 | 38662篇 |
基础医学 | 187206篇 |
口腔科学 | 39811篇 |
临床医学 | 112614篇 |
内科学 | 262368篇 |
皮肤病学 | 30205篇 |
神经病学 | 106372篇 |
特种医学 | 53666篇 |
外国民族医学 | 435篇 |
外科学 | 208207篇 |
综合类 | 31043篇 |
现状与发展 | 6篇 |
一般理论 | 437篇 |
预防医学 | 92039篇 |
眼科学 | 31357篇 |
药学 | 100050篇 |
4篇 | |
中国医学 | 2987篇 |
肿瘤学 | 75613篇 |
出版年
2018年 | 11738篇 |
2015年 | 11873篇 |
2014年 | 16686篇 |
2013年 | 25238篇 |
2012年 | 32994篇 |
2011年 | 34860篇 |
2010年 | 20730篇 |
2009年 | 20226篇 |
2008年 | 33569篇 |
2007年 | 36676篇 |
2006年 | 37249篇 |
2005年 | 36005篇 |
2004年 | 35083篇 |
2003年 | 34057篇 |
2002年 | 33585篇 |
2001年 | 63613篇 |
2000年 | 65322篇 |
1999年 | 55386篇 |
1998年 | 14651篇 |
1997年 | 13458篇 |
1996年 | 12937篇 |
1995年 | 12221篇 |
1994年 | 11467篇 |
1992年 | 42761篇 |
1991年 | 41280篇 |
1990年 | 40554篇 |
1989年 | 39551篇 |
1988年 | 36963篇 |
1987年 | 36408篇 |
1986年 | 34899篇 |
1985年 | 33102篇 |
1984年 | 24822篇 |
1983年 | 21052篇 |
1982年 | 12665篇 |
1981年 | 11568篇 |
1980年 | 10772篇 |
1979年 | 23923篇 |
1978年 | 17069篇 |
1977年 | 14836篇 |
1976年 | 13387篇 |
1975年 | 15268篇 |
1974年 | 18080篇 |
1973年 | 17562篇 |
1972年 | 16810篇 |
1971年 | 15717篇 |
1970年 | 14915篇 |
1969年 | 14347篇 |
1968年 | 13461篇 |
1967年 | 12016篇 |
1966年 | 11259篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
We identified the ADP/ATP carrier, located within the inner mitochondrial membrane, to be an organ- and conformation-specific autoantigen in myocarditis and dilated cardiomyopathy. We also showed that autoantibodies to the ADP/ATP carrier inhibit the nucleotide transport in vitro. Specific binding of the autoantibodies to the carrier was demonstrated by radioimmunoassay and the immunoblot technique; the inhibition of the nucleotide transport was determined by the inhibitor stop method. To establish if these autoantibodies might also affect cardiac energy metabolism in vivo, we measured whether they are capable of penetrating into myocytes and whether subcellular ATP/ADP ratios and phosphorylation potentials of ATP change in hearts of guinea pigs that have been immunized with the isolated ADP/ATP carrier. An intracellular deposition of autoantibodies was observed by direct immunofluorescence and by immunoperoxidase staining on cryosections of the myocardial tissue of animals immunized with the ADP/ATP carrier. Furthermore, binding of autoantibodies to mitochondrial membrane structures was shown by immunoelectron-microscopic methods. The cytosolic and intramitochondrial distribution of adenine nucleotides in stimulated, isolated perfused hearts of guinea pigs immunized with the ADP/ATP carrier was measured by nonaqueous fractionation. Compared with controls performing equal external heart work, the cytosolic ATP decreased in the immunized animals, whereas the mitochondrial ATP increased strongly; ADP concentrations showed an opposite change. Thus, a resultant cytosolic decrease and a marked mitochondrial increase of the ATP/ADP ratio was established. As a consequence, the cytosolic-mitochondrial phosphorylation potential of ATP was diminished. These findings demonstrate that antibodies against intracellular antigens are able to penetrate into living cells, and that autoimmunity to the ADP/ATP carrier may contribute to the pathophysiology of myocarditis and dilated cardiomyopathy by causing an autoantibody-mediated imbalance between intracellular energy delivery and demand. 相似文献
982.
A 64-year-old woman presented in shock. The computed tomography (CT) scan confirmed rupture of the left diaphragm with strangulation. Three days after surgery, the patient developed herniation of abdominal contents on the right side with cardiorespiratory collapse. Marlex mesh was used to repair on the right side. Postoperatively, she needed partial gastrectomy for massive duodenal ulcer bleeding. A dual chamber pacemaker was used to correct the complete heart block. 相似文献
983.
Insulin-like growth factors (IGF-I and -II) are peptide growth factors that may be important for neonatal development. Specific high affinity IGF binding proteins (BPs) have been characterized in serum and extracellular fluids. The major serum binding complex in the adult has an apparent Mr of 150 K, while the predominant BP in the neonate is approximately 30 K. In the rat, the transition from the neonatal BP to the adult form occurs during the third postnatal week, concomitant with an increase in serum IGF-I and a decrease in serum IGF-II concentrations. Using specific RIAs and Western ligand blot analyses we have characterized the changes in serum IGF and IGF BPs, respectively, during the early postnatal period. Seven BPs were identified in serum with apparent Mr values of 42, 41, 40, 38, 28, 26, and 22 K. After deglycosylation, the 42, 41, 40, and 38 K BPs were reduced to two bands with apparent Mr values of 35 and 32 K, while the 28, 26, and 22 K BP were unchanged. In the neonate, the 28, 26, and 22 K BPs were present, with the 28 K BP in highest concentration. With increasing age, the 28 K BP decreased and the 42, 41, 40, and 38 K BPs appeared at approximately 19 days of age. Comparison of Western ligand blots of neonatal serum, BRL-3A conditioned media, rat amniotic fluid, and rat cerebrospinal fluid (CSF) demonstrated that all contained a prominent 28 K BP. A polyclonal antibody (alpha Hec 1) developed against the 31 K human IGF-BP (hBP-31) immunoprecipitated the 28 K BP from neonatal rat serum, BRL-3A media, rat amniotic fluid, and rat CSF, but did not react with adult rat serum. These findings suggest that, in the rat, the predominant neonatal serum BP is structurally and immunologically similar to the major BRL-3A, amniotic fluid, and CSF BPs, but distinct from the predominant adult serum BP. 相似文献
984.
Elevated serum levels of keratan sulfate (KS) and hyaluronate (HA) in patients with osteoarthritis (OA) have been reported. We measured KS and HA in dogs to determine if there was an elevation of these serum glycosaminoglycans in a canine model of OA. A single intraarticular injection of 1 mg of chymopapain into a shoulder joint increased serum KS by tenfold, and HA by less than twofold, in 24 hours. Serum KS and HA levels were 3-5-fold higher in dogs younger than 2 months of age than in older dogs. Serum KS and HA concentrations and synovial fluid KS concentrations were unrelated to spontaneous cartilage degeneration in 1-year-old dogs. Higher KS levels in synovial fluid correlated with higher KS levels in serum (r = 0.54, P less than 0.025). The mean KS concentration in sera of older dogs (greater than 3 years old) with OA was 37% higher than that in disease-free controls, but the difference between the groups was not statistically significant. Thus, elevated levels of serum KS and HA do not appear to have clinical significance in this model of OA. 相似文献
985.
Plasma D-dimer (DD) and thrombin--antithrombin III complex (TAT) were measured with ELISAs in 99 patients investigated by 102 ventilation--perfusion lung scintigraphy because of suspected pulmonary embolism. High-probability lung scan was associated with increased DD (more than 500 ng/ml) and TAT (more than 4.1 ng/ml) levels (sensitivity of 100 and 70%, respectively). The corresponding figures of specificity were 81 and 42%. In the 56 patients with low-probability or indeterminate probability scans, 31 (55%) had DD concentrations of less than 500 ng/ml. These preliminary data suggest that a plasma DD concentration of less than 500 ng/ml might rule out the diagnosis of pulmonary embolism in suspected patients with an inconclusive lung scanning. 相似文献
986.
987.
Acute myocardial infarction after heart irradiation in young patients with Hodgkin's disease 总被引:1,自引:0,他引:1
Forty-seven patients younger than 40 years at the time of the diagnosis, and irradiated to the mediastinum for Hodgkin's disease at Turku University Central Hospital from 1977 to 1982, were regularly followed for 56 to 127 months after therapy. Two patients developed an acute myocardial infarction ten and 50 months after cardiac irradiation at the age of only 28 and 24 years, respectively. None of the patients died from lymphoma within five years from the diagnosis, but one of the infarctions was eventually fatal. Since acute myocardial infarction is rare in this age group, the result suggests strongly that prior cardiac irradiation is a risk factor for acute myocardial infarction. The possibility of radiation-induced myocardial infarction should be taken into account both in treatment planning and follow-up of patients with Hodgkin's disease. 相似文献
988.
The activation of phospholipase A2 is believed to have an important role in the inflammatory process owing to its induction of eicosanoids, platelet activating factor, and other mediators. Soluble phospholipase A2 has been associated with exudates in different inflammatory conditions. In this review the general physiology and control of this enzyme and, in particular, the most recent findings on human synovial fluid phospholipase A2s are discussed. 相似文献
989.
Transfusion-induced alloimmunization and immunosuppression and the effects of leukocyte depletion 总被引:2,自引:0,他引:2
H T Meryman 《Transfusion medicine reviews》1989,3(3):180-193
990.