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排序方式: 共有800条查询结果,搜索用时 15 毫秒
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Chronic exposure of humans to benzene (BZ), a myelotoxin, causes aplastic anemia and acute leukemia. The stromal macrophage that produces interleukin-1 (IL-1), a cytokine essential for hematopoiesis, is a target of BZ's toxicity. Monocyte dysfunction and decreased IL-1 production have been shown to be involved in aplastic anemia in humans. Hydroquinone (HQ), a toxic bone marrow (BM) metabolite of BZ, causes time- and concentration-dependent inhibition of processing of the 34-Kd pre-interleukin-1 alpha (IL-1 alpha) to the 17-Kd mature cytokine in murine P388D1 macrophages and BM stromal macrophages, as measured by Western immunoblots of cell lysate proteins using a polyclonal rabbit antimurine IL-1 alpha antibody. HQ over a 10-fold concentration range had no effect on the lipopolysaccharide (LPS)-induced production of pre- IL-1 alpha precursor or on cell viability or DNA and protein synthesis. Stromal macrophages obtained from the femoral BM of C57Bl/6 mice exposed to BZ (600 or 800 mg/kg body weight) for 2 days were incapable of processing the 34-Kd pre-IL-1 alpha to the mature 17-Kd cytokine when stimulated in culture with LPS. Stromal macrophages from mice coadministered BZ and indomethacin, a prostaglandin H synthase (PHS) inhibitor that has been shown to prevent BZ-induced myelotoxic and genotoxic effects in mice when coadministered with benzene were able to convert the pre-IL-1 alpha to mature cytokine. Administration of recombinant murine IL-1 alpha (rMuIL-1 alpha) to mice before a dose of BZ that causes severe depression of BM cellularity completely prevents BM depression, most probably by bypassing the inability of the stromal macrophage in BZ-treated animals to process pre-IL-1 alpha to the mature cytokine. 相似文献
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A kindred with MYH-associated polyposis and pilomatricomas 总被引:4,自引:0,他引:4
Baglioni S Melean G Gensini F Santucci M Scatizzi M Papi L Genuardi M 《American journal of medical genetics. Part A》2005,(2):212-214
MYH-associated polyposis (MAP) is a recently described autosomal recessive form of familial adenomatous polyposis (FAP) associated with susceptibility to colorectal carcinoma (CRC). MAP is caused by biallelic inactivating mutations of the MYH gene, a component of the base excision repair (BER) machinery, whose dysfunction leads to an increase in the rate of G > T transversions following DNA oxidative damage. MAP patients can present with either classic or attenuated polyposis. However, the MAP colonic and extracolonic phenotype has yet to be defined. We report on two siblings, born from consanguineous parents, who were found to be homozygotes for an MYH frameshift mutation. The propositus presented with a low number of colonic lesions and an early-onset CRC. Both siblings had a history of pilomatricomas, benign tumors derived from hair follicles, in childhood. The findings presented provide further evidence of phenotypic variability in MAP, and suggest that multiple pilomatricomas may be a useful cutaneous marker of MAP. 相似文献
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Macchi C Popolizio A Casamorata F Bicchi S Pieroni A Molino Lova R Miniati B Gulisano M Catini C Conti AA Gensini GF 《Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia》2002,107(2):93-97
Fifty-four subjects, aged between 20 and 35 years, divided into two subgroups, respectively 30 healthy subjects (17 males and 13 females) and 24 subjects with "gonalgia sine materia" (13 males and 11 females) underwent isokinetic exercise test in order to compare their dominant limb with the not dominant one as regard as the strength of extensor and flexor muscles of the knee. No statistically significant difference was found in any of the studied parameters in the comparison between the dominant limb and the not dominant one, both within the subgroup of healthy subjects and within the subgroup of subjects with "gonalgia sine materia". Authors conclude that psychological features may play a preeminent role in the genesis, as well as in the maintenance of "gonalgia sine materia", thus confirming previous data available in medical literature. 相似文献
7.
Background
Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population. 相似文献8.
Direct evidence for the involvement of carbohydrate sequences in human sperm-zona pellucida binding 总被引:2,自引:0,他引:2
Several lines of evidence indicate that mammalian fertilization is
initiated via a binding process that is dependent upon the recognition of
oligosaccharide sequences associated with zona pellucida (ZP)
glycoproteins. Here, specific chemical and enzymatic methods were employed
to modify human ZP and to test their effects on sperm binding in the
hemizona assay system (HZA). Periodate oxidation of human ZP under very
mild conditions (10 min, 0 degrees C, 1 mM sodium m- periodate) that
attacks only terminal sialic acid resulted in a 30% loss of human sperm
binding in the HZA [hemizona index (HZI) = 70.2 +/- 10.9, n = 22; P <
0.05]. Periodate oxidation under mild conditions (1 h, 23 degrees C, 10 mM
sodium m-periodate) caused a 40% decrease in binding (HZI = 60.8 +/- 10.3;
n = 24; P< 0.01). Treatment of human ZP with neuraminidase caused a
substantial increase in sperm binding to human ZP (HZI = 297 +/- 45, n =
22; P < 0.01). These findings indicate that there are sialic acid
dependent binding sites coexisting with binding sites that are obscured by
sialic acid. To determine the periodate sensitivity of these obscured
sites, hemizona were first digested with neuraminidase and subsequently
subjected to mild periodate oxidation. The combined enzymatic and chemical
treatments caused a 79% decrease in sperm binding compared to control
hemizona (HZI = 20.7 +/- 4.4, n = 16; P < 0.001). Human sperm-ZP
interaction was also increased by digestion of human ZP with
endo-beta-galactosidase (HZI = 710 +/- 232, n = 14; P < 0.01),
indicating that potential binding sites for spermatozoa are also obscured
by lactosaminoglycan sequences. These studies support a definitive role for
the involvement of ZP-associated glycans in the binding of human
spermatozoa to oocytes.
相似文献
9.
R Marcucci R Abbate S Fedi A M Gori T Brunelli V Bruni S Bucciantini S Micheli G Pepe D Prisco G F Gensini 《American journal of clinical pathology》1999,111(6):769-772
Activated protein C (APC) resistance is an established risk factor for venous thromboembolism. In 5% to 10% of patients with venous thromboembolism, the APC resistance phenotype is observed in the absence of factor V Leiden mutation. Moreover, some physiologic and pathologic conditions are associated with an "acquired" APC resistance, not caused by the Leiden mutation, such as inflammatory diseases, pregnancy, or oral contraceptive therapy. Several studies have demonstrated the effect of menopause on the hemostatic system, but no data are available about APC resistance. We found a high prevalence of APC resistance in postmenopausal women, not associated with factor V Leiden mutation. The mechanism that underlies this acquired APC resistance may be related to the higher levels of factor VIII, which showed a strong inverse correlation with APC resistance, whereas no correlation was found between the normalized APC ratio, factor V levels, and protein S values. Higher levels of factor VIII correlated with a marker of coagulation activation, such as prothrombin fragments 1 plus 2. Therefore, to identify women receiving hormone replacement therapy who have a greater risk for deep venous thrombosis, the APC resistance coagulation test should be used instead of the genetic study. 相似文献
10.
A 35 year old man with a history of transient ischaemic attack and atrial septal aneurysm underwent percutaneous closure of a patent foramen ovale (PFO) with a transcatheter device. After the procedure the patient developed effort angina not present previously. Transoesophageal echocardiography confirmed the absence of residual shunt but showed an abnormal linear image running behind the aortic root. Magnetic resonance imaging detected an anomalous origin of the circumflex coronary artery from the right coronary sinus. The anomalous artery was located between the aortic root and the PFO closing device, causing coronary insufficiency. This report describes a rare complication of transcatheter PFO closure. 相似文献