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排序方式: 共有1492条查询结果,搜索用时 31 毫秒
991.
Homograft insertion for pulmonary regurgitation after repair of tetralogy of fallot improves cardiorespiratory exercise performance 总被引:6,自引:0,他引:6
Eyskens B Reybrouck T Bogaert J Dymarkowsky S Daenen W Dumoulin M Gewillig M 《The American journal of cardiology》2000,85(2):221-225
Surgical repair of tetralogy of Fallot (TOF) with reconstruction of the right ventricular (RV) outflow tract invariably results in pulmonary regurgitation. Chronic pulmonary regurgitation has been associated with RV dysfunction and decreased exercise performance. The present study assessed the influence of pulmonary valve replacement (PVR) for severe pulmonary regurgitation after previous TOF repair on cardiorespiratory exercise performance and RV function. Eighteen patients, between the ages of 8 and 18 years, underwent an exercise test and a cardiac magnetic resonance imaging scan at least 1 year after PVR. The exercise data were compared with those obtained from 24 age-matched normal controls and 27 age-matched patients with repaired TOF and a moderate degree of pulmonary regurgitation. A subgroup of 11 patients had an exercise test performed before and after PVR. Cardiopulmonary exercise performance was evaluated by determination of the ventilatory anaerobic threshold (VAT) and by the steepness of the slope of oxygen uptake versus exercise intensity (SVO2). After PVR there was a significant increase in VAT (86+/-11% before to 106.9+/-14% after, p = 0.03) and in SVO2 (1.71+/-0.47 to 2.3+/-0.39, p = 0.004). In patients examined after PVR, the VAT and SVO2 values were not significantly different from the values in the normal controls (104+/-15% [p>0.05] and 2.03+/-0.77 after PVR vs. 2.42+/-0.68 [p>0.25], respectively). In contrast, patients with repaired TOF and a moderate degree of pulmonary regurgitation had a significantly lower VAT (86+/-11%, p<0.05) and SVO2 (1.8+/-0.74 vs. 2.42+/-0.68, p<0.05) than normal controls. Magnetic resonance imaging studies revealed residual RV dilatation and dysfunction. However, there was no correlation between RV dilatation and RV dysfunction and aerobic exercise capacity. It is concluded that aerobic exercise capacity substantially improves after PVR for severe pulmonary regurgitation after previous TOF repair. Although the right ventricle remains significantly dilated and hypocontractile, there is no relation between RV function and exercise performance. 相似文献
992.
993.
Derize Elizabeth Boshoff No?lla Bethuyne Marc Gewillig Luc Mertens Benedicte Eyskens Ihsan Bakir Eric Verbeken Willem Daenen Bart Meyns 《European heart journal》2007,28(8):1033-1036
AIMS: To investigate the effect of stenting and later surgical removal on the architecture and therefore growth potential of juvenile vessels. METHODS AND RESULTS: Stents were implanted in the carotid artery and jugular vein of six 6-week-old lambs. Ten weeks later, stents were excised and the vessels closed without the use of patch material. After another 10 weeks, the vessel size (treated and untreated control side) was measured angiographically and the animals terminated for histology. All arteries were patent: treated arterial size was 9 +/- 1 mm compared with 11 +/- 1 mm on the control side (P = ns). Two veins were completely occluded and two severely stenosed; vessel size was smaller compared with the control side (8 +/- 8 vs. 14 +/- 5 mm; P = 0.02). Preserved vessel wall integrity was observed in both arteries and veins (except for local rupture of the internal elastic lamina with neointimal formation in two arteries leading to mild stenosis). CONCLUSION: Vessel wall architecture remains well preserved after surgical removal of stents implanted in juvenile arteries and veins. However, stenting and subsequent surgical removal results in a high risk of venous thrombosis (probably due to the lower blood velocity, lower pressure, and the absence of pulsatility in venous vessels). 相似文献
994.
Platelet release has been alternatively viewed as a fragmentation of platelet territories demarcated within the cytoplasm of mature megakaryocytes or as a later event involving segmentation of proplatelet pseudopodia extended from the cell. The mechanical constraints on platelet release were evaluated by measuring the resistance of guinea pig megakaryocytes to aspiration into micropipettes of similar diameter to the width of naturally forming proplatelet projections. Application of increasing negative pressure to the surface of the cells resulted in progressively longer extensions being drawn into the pipette until maximal extension lengths were reached. None of the passively aspirated cytoplasmic extensions fragmented off the cells even at the highest aspiration pressure under physiologic study conditions. The longest extensions were aspirated from megakaryocytes of the most advanced maturation stage, and a proportion of the mature cells yielded very long extensions over 50 mu and up to 150 mu in length. Surprisingly, the ease of aspiration did not correlate to cell size during any stage of maturation. The mechanical behavior of guinea pig megakaryocytes indicates a large availability of surface for extension in mature cells ideal for active proplatelet projection. The lack of mechanical fragility suggests that platelet release is a very late maturational event not yet initiated in the "mature" megakaryocytes available for study from marrow harvests. 相似文献
995.
Spleen cell production of granulocyte-macrophage colony stimulating activity (CSA) and colony forming capacity (CFU-GM) from 59 patients with Hodgkin's and non-Hodgkin's lymphoma, acute (AML) and chronic myeloid leukemia (CML), and control subjects was quantified to evaluate local cellular potential for modulating splenic granulocytopoiesis. Mononuclear spleen cell conditioned media stimulated myeloid CFU-GM by human nonadherent marrow target cells. In contrast to conditioned media produced by marrow and peripheral blood cells, the vast majority of spleen CSA was generated by nonadherent lymphoid cells rather than adherent monocytic cells. The nonadherent cells producing CSA were non- T cells (assessed by sheep erythrocyte rosetting), with 98% +/- 2% CSA produced by the nonrosetted fraction (B lymphocytes and null cells), and had a peak density heavier than that of the adherent spleen CSA- producing cells. Dose response curves demonstrated significantly increased cellular CSA production from patients with lymphomas and AML in remission. In a high proportion of patients, foci of immature granulocytic cells were found by specific cytochemical staining of histologic sections of spleens. A limited degree of splenic granulocytopoiesis was demonstrated morphologically and by CFU-GM incidence. CSA was not detectable in conditioned medium prepared from nonadherent spleen cells from 5 patients with CML, due to a nondialyzable substances(s) produced by the nonadherent cells which inhibited normal CFU-GM response to CSA. The high CFU-GM incidence and extensive leukemic granulocytopoiesis present in the CML spleens suggests diminished effect of this inhibitor on leukemic as opposed to normal granulocytic precursor cell proliferation. 相似文献
996.
Isolated follicular lymphoma cells are resistant to apoptosis and can be grown in vitro in the CD40/stromal cell system 总被引:4,自引:2,他引:4
Low-grade follicular non-Hodgkin's lymphomas are characterized by the presence of a t(14;18) chromosomal translocation that results in deregulation of the B-cell lymphoma (Bcl-2) gene. Studies in cell lines and transgenic animal models have suggested that this results in the suppression of apoptotic cell death in germinal centers. B lymphocytes from normal germinal centers and lymph nodes infiltrated by follicular lymphoma were isolated by immunomagnetic depletion of cells bearing CD4, CD8, or slgD for study in vitro. Follicular lymphoma cells expressing Bcl-2 protein were shown to resist apoptosis after isolation, and could be induced to proliferate in a culture system previously described for the growth of normal B lymphocytes. By the use of a mouse fibroblast monolayer transfected with the CDw32 Fc receptor to present CD40 monoclonal antibody in the presence of interleukin-4, prolonged culture was possible. Karyotypic analysis of cultured lymphoma cells showed the t(14;18) translocation, with clonal identity confirmed by polymerase chain reaction amplification of the breakpoints and direct sequence analysis. These findings support the hypothesis that resistance to apoptosis is an influence on the initiation of follicular lymphoma, and provide a novel means of studying in vitro the intercellular reactions that may be important in progression of the disease. 相似文献
997.
Decreased nucleotide and serotonin storage associated with defective function in Chediak-Higashi syndrome cattle and human platelets 总被引:5,自引:0,他引:5
Prolonged mean template bleeding time of 14 min observed in seven cattle with the Chediak-Higashi syndrome (CHS) prompted the examination of platelet function in these animals. There was no distinguishable difference in concentration of circulating platelets between CHS and control cattle. CHS bovine platelets failed to aggregate in vitro in response to concentrations of acid-soluble collagen which induced aggregation in all normal samples. The primary platelet response to 5 muM ADP was normal in CHS cattle. A markedly decreased amount of serotonin (1.2% of normal) was detected in CHS bovine platelets. Bovine CHS platelet ATP and ADP contents were significantly less than normal, and the ATP/ADP ratios were 5.04 in normal and 29.38 in CHS platelets. Results of these animal investigations prompted a similar study of two patients with CHS. In humans, an increased bleeding time greater than 15 min and an in vitro impaired aggregation response to acid-soluble collagen and 5 muM adrenaline were discovered. Both ATP and ADP were reduced in CHS human platelets, and the ATP/ADP ratio was 3.96, compared to a ratio of 1.52 for platelets of two normal subjects. These findings suggested the presence of a "storage pool disease" of CHS platelets. 相似文献
998.
Wong PM; Chung SW; White JS; Reicheld SM; Patterson M; Clarke BJ; Chui DH 《Blood》1983,62(6):1280-1288
The hemoglobins present in murine fetal hepatic erythroblasts on days 12-15 of gestation were studied by biochemical and immunocytologic techniques. In addition, fetal hepatic hemopoietic progenitor cells obtained from normal and mutant f/f mouse fetuses on days 11-13 of gestation were cultured in vitro with added erythropoietin and adult spleen cell conditioned medium to form large erythroid colonies. In all instances, adult hemoglobin synthesis was detected in the fetal hepatic erythroblasts and in the erythroid cell cultures in vitro. The tumor promoter, 12-O-tetradecanoylphorbol 13-acetate, enhanced the fetal hepatic erythroid colony growth in vitro, but did not alter the hemoglobin phenotypic expression. 相似文献
999.
Liposomal amphotericin B compared with amphotericin B deoxycholate in the treatment of documented and suspected neutropenia-associated invasive fungal infections 总被引:11,自引:0,他引:11
Alexander C. A. P. Leenders Simon Daenen Rob L. H. Jansen Wim C. J. Hop Bob Lowenberg Pierre W. Wijermans Jan Cornelissen Raoul Herbrecht Hans Van Der Lelie Henk C. Hoogsteden Henri A. Verbrugh & Siem De Marie 《British journal of haematology》1998,103(1):205-212
It has been suggested that a better outcome of neutropenia-associated invasive fungal infections can be achieved when high doses of lipid formulations of amphotericin B are used. We now report a randomized multicentre study comparing liposomal amphotericin B (AmBisome, 5 mg/kg/d) to amphotericin B deoxycholate (AmB, 1 mg/kg/d) in the treatment of these infections. Of 106 possible patients, 66 were enrolled and analysed for efficacy: nine had documented fungaemia, 17 had other invasive mould infections and 40 had suspected pulmonary aspergillosis. After completion of the course medication, in the AmBisome group ( n = 32) 14 patients had achieved complete response, seven a partial response and 11 were failures as compared to 6, 13 and 15 patients ( n = 34) treated with AmB ( P = 0.09); P = 0.03 for complete responders. A favourable trend for AmBisome was found at day 14, in patients with documented infections and in patients with pulmonary aspergillosis ( P = 0.05 and P = 0.096 respectively). Mortality rates were lower in patients treated with AmBisome (adjusted for malignancy status, P = 0.03). More patients on AmB had a >100% increase of their baseline serum creatinine ( P < 0.001).
The results indicate that, in neutropenic patients with documented or suspected invasive fungal infections AmBisome 5 mg/kg/d was superior to AmB 1 mg/kg/d with respect to efficacy and safety. 相似文献
The results indicate that, in neutropenic patients with documented or suspected invasive fungal infections AmBisome 5 mg/kg/d was superior to AmB 1 mg/kg/d with respect to efficacy and safety. 相似文献
1000.
Excessive bronchoconstriction induced by histamine and effects of volume history in patients with bronchial asthma 总被引:1,自引:0,他引:1
Abstract The aim of this study was to examine the inter-relationships between the different effects of deep breaths and histamine provocation on airway function in patients with bronchial asthma. Group 1 consisted of 38 consecutive out-patients with newly diagnosed mild asthma, group 2 consisted of 20 patients with bronchial asthma of varying severity who were studied during clinical remission. We measured bronchial responsiveness (BR) to histamine inhalation as the dose of histamine which provoked a 20% fall in FEV1 (PD20). The fall in forced vital capacity (FVC) after inhaling the highest dose of histamine during each BR test was calculated and expressed as percentage of the value measured at baseline (δFVC in percentage). We studied the effects of deep breaths on airway caliber in group 2 patients by comparing isovolumic flow rates on partial (P) and maximal (M) forced expiratory flow volumes curves expressed as the M/P ratio. The changes in residual volume (RV) after deep breaths (δRV) were expressed as a percentage of the largest VC measured on the composite M and P curves. The patients in group 1 had significantly higher PD20 and lower δFVC than patients in group 2. There was, however, no significant correlation between PD20 and δFVC measurements in individual patients (r<0.1, P>0.05). The M/P ratio was significantly related to δFVC (r=?0.6, P<0.006). There was also a significant positive relation between the magnitude of increase in residual volume following deep breaths (δRV) and the degree of fall in FVC following histamine inhalation (δFVC) (r= 0.65, P= 0.001). This significant relationship between the degree of airway closure after a deep breath and airway closure after histamine challenge is a new finding. In patients with bronchial asthma, the effects of a deep breath on airway function may be indicative of the tendency for airway closure during BR testing. 相似文献