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61.
Engraftment of bone marrow cells into normal unprepared hosts: effects of 5-fluorouracil and cell cycle status 总被引:2,自引:7,他引:2
Bone marrow from animals treated with 5-fluorouracil (5FU) competes equally with normal marrow when assessed in vivo in an irradiated mouse, but shows markedly defective engraftment when transplanted into noncytoablated hosts. Using Southern Blot analysis and a Y-chromosome specific probe, we determined the level of engraftment of male donor cells in the bone marrow, spleen, and thymus of unprepared female hosts. We have confirmed the defective engraftment of marrow harvested 6 days after 5FU (FU-6) and transplanted into unprepared hosts and shown that this defect is transient; by 35 days after 5FU (FU-35), engraftment has returned to levels seen with normal marrow. FU-6 marrow represents an actively cycling population of stem cells, and we hypothesize that the cycle status of the stem cell may relate to its capacity to engraft in the nonirradiated host. Accordingly, we have evaluated the cycle status of engrafting normal and FU-6 marrow into normal hosts using an in vivo hydroxyurea technique. We have shown that those cells engrafting from normal marrow and over 70% of the cells engrafting from FU-6 marrow were quiescent, demonstrating no killing with hydroxyurea. We have also used fluorescent in situ hybridization (FISH) analysis with a Y-chromosome probe and demonstrated that normal and post-5FU engraftment patterns in peripheral blood were similar to those seen in bone marrow, spleen, and thymus. Altogether these data indicate that cells engrafting in normal, unprepared hosts are dormant, and the defect that occurs after 5FU is concomitant with the induction of these cells to transit the cell cycle. 相似文献
62.
对QT离散度实质的探讨 总被引:2,自引:0,他引:2
为探讨QT离散度(QTd)的真实意义,观察139例急性心肌梗死(AMI,AMI组)及109例正常人(对照组)的最长QT间期(QTmax)、校正QTmax(QTcmax)及QTd的变化。结果:①AMI组的QTmax、QTcmax和QTd均显著高于对照组(分别为422.60±30.51msvs382.46±23.40ms、460.21±28.96msvs388.51±20.15ms、59.80±28.40msvs39.43±12.21ms,P均<0.001)。②AMI组中发生严重室性心律失常(VA)患者(114例)的QTmax、QTcmax、QTd与无VA的患者(25例)相比,均有显著差异(分别为448.58±33.40msvs416.10±35.30ms、481.43±35.17msvs439.60±27.10ms、66.90±20.72msvs48.32±23.61ms,P均<0.001)。认为AMI时QTd系T向量环在不同导联上的“投影”差异所引起的,其异常的本质是QT间期延长 相似文献
63.
Marijan Bosevski Sabita S. Soedamah-Muthu 《Diabetes & Metabolic Syndrome: Clinical Research & Reviews》2012,6(1):32-35
AimThe purpose of the study was to determine factors of ankle-brachial index (ABI) in a population of patients with type 2 diabetes and coronary artery disease.Material and methods370 patients (mean age 60.3 ± 8.3 years and diabetes duration 8.6 ± 6.2 years) with type 2 diabetes and coronary artery disease were enrolled in a cross sectional study during 2006–2007. Multivariable linear regression analysis was conducted to determine the factors of ABI, considering systolic and diastolic blood pressure, weight, body mass index, waist circumference, glycemia, urea, creatinin, triglycerides, total cholesterol, LDL- and HDL-cholesterol.ResultsPeripheral arterial disease was detected in 82.35% (280 pts). Mean ABI value of 0.97 ± 0.33, and its minimal value of 0.95 ± 0.38 was detected in this study population. Regression analysis demonstrated that mean and minimal values of ABI were independently associated with diabetes duration (β 0.120, 95% CI ?0.014, ?0.001) and blood urea level (β ?0.126, 95% CI ?0.020, ?0.002).ConclusionResults might have clinical implications for patients with type 2 diabetes and coronary artery disease in defining those with a long diabetes duration and a higher blood urea level to have greater probability of detecting pathological ankle-brachial index. 相似文献
64.
Mouse bone marrow (BM) was separated into low-density, lineage- negative, wheat germ agglutinin-positive (WGA+), Rhodamine-123 bright (Rhbright) or dim (Rhdim) cells to obtain populations that were highly enriched for committed progenitors (Rhbright cells) or for more primitive stem cells (Rhdim). When 2,500 Rhbright or Rhdim cells were seeded onto 6-week-old irradiated (20 Gy) long-term BM cultures (LTBMC), the nonadherent cell production from Rhbright cells was transient and ended after 5 weeks. Production from Rhdim cells did not begin until week 3, peaked at week 5, and ended at week 8, when the irradiated stroma seemed to fail. Termination of cell production from Rhdim cells did not occur in nonirradiated LTBMC from W41/Wv mice. During peak nonadherent cell production, 25% to 30% of the cells in the nonirradiated LTBMC from W41/Wv mice had donor cell markers. Two approaches were tested to try to enhance the proportion or number of donor cells. Addition of Origen-HGF at the time of seeding Rhdim cells caused a nonspecific increase in both host and donor cell production, but a specific increase in production of donor cells was obtained by seeding the cultures at 2 weeks rather than 6 weeks. Limiting dilution of Rhdim cells gave the same frequency of wells producing cells on both irradiated +/+ and nonirradiated W41/Wv or W/Wv cultures. 相似文献
65.
Mulnier HE Seaman HE Raleigh VS Soedamah-Muthu SS Colhoun HM Lawrenson RA De Vries CS 《Diabetologia》2006,49(12):2859-2865
Aims/hypothesis Risk estimates for stroke in patients with diabetes vary. We sought to obtain reliable risk estimates for stroke and the association with diabetes, comorbidity and lifestyle in a large cohort of type 2 diabetic patients in the UK.Materials and methods Using the General Practice Research Database, we identified all patients who had type 2 diabetes and were aged 35 to 89 years on 1 January 1992. We also identified five comparison subjects without diabetes and of the same age and sex. Hazard ratios (HRs) for stroke between January 1992 and October 1999 were calculated, and the association with age, sex, body mass index, smoking, hypertension, atrial fibrillation and duration of diabetes was investigated.Results The absolute rate of stroke was 11.91 per 1,000 person-years (95% CI 11.41–12.43) in people with diabetes (n = 41,799) and 5.55 per 1,000 person-years (95% CI 5.40–5.70) in the comparison group (n = 202,733). The age-adjusted HR for stroke in type 2 diabetic compared with non-diabetic subjects was 2.19 (95% CI 2.09–2.32) overall, 2.08 (95% CI 1.94–2.24) in men and 2.32 (95% CI 2.16–2.49) in women. The increase in risk attributable to diabetes was highest among young women (HR 8.18; 95% CI 4.31–15.51) and decreased with age. No investigated comorbidity or lifestyle characteristic emerged as a major contributor to risk of stroke.Conclusions/interpretation This study provides risk estimates for stroke for an unselected population from UK general practice. Patients with type 2 diabetes were at an increased risk of stroke, which decreased with age and was higher in women. Additional risk factors for stroke in type 2 diabetic patients included duration of diabetes, smoking, obesity, atrial fibrillation and hypertension. 相似文献
66.
Reversible oxidant-induced increases in albumin transfer across cultured endothelium: alterations in cell shape and calcium homeostasis 总被引:20,自引:0,他引:20
To determine whether reactive oxygen molecules could directly and reversibly increase the transfer of albumin across an endothelial barrier, we measured albumin transfer across monolayers of endothelium cultured on micropore filters before and after exposure to xanthine and xanthine oxidase. Xanthine and xanthine oxidase increased endothelial albumin transfer in a dose-dependent fashion. Parallel phase contrast and fluorescence microscopy demonstrated retraction of adjacent cells from one another and disruption of the actin filaments. The oxidant- induced increases in albumin transfer and changes in cell shape were reversed by removing xanthine oxidase and then incubating the monolayers for 3 1/2 hours in tissue culture media enriched with fetal bovine serum. However, incubation in tissue culture media without serum resulted in progressive injury and cell death. Hence, the brief exposure to oxidants initiated a progressive injury process that was reversed by incubation in serum. Because intracellular and extracellular calcium are important determinants of cell shape, and because some oxidized membrane lipids act as calcium ionophores, we asked whether oxidants altered endothelial calcium homeostasis. Xanthine-xanthine oxidase increased release of 45Ca++ from preloaded cells. The calcium antagonist lanthanum chloride prevented xanthine- xanthine oxidase increases in endothelial albumin transfer and prevented the changes in cell shape; chelation of extracellular calcium inhibited lysis of endothelium by xanthine-xanthine oxidase; and the calcium ionophore A23187 increased endothelial albumin transfer and mimicked the oxidant-induced changes in cell shape. Lanthanum chloride inhibited these effects of A23187. These data suggest that oxygen radicals can reversibly increase endothelial permeability to macromolecules, that this is associated with reversible changes in endothelial cell shape and actin filaments, and that the changes in cell shape are related to oxidant-induced changes in endothelial calcium homeostasis. 相似文献
67.
The patterns of cell proliferation and cell migration were studied in three patients with the Sezary syndrome using autoradiographic techniques. Cell labeling patterns following pulse labeling with tritiated thymidine in vivo indicated that Sezary cells proliferate actively in skin and in lymph nodes but that few if any Sezary cells proliferate in the peripheral blood. In two of the patients serial samples were obtained. Label dilution patterns in skin and blood over time suggested that circulating Sezary cells originated in extracutaneous sites where cells were proliferating more rapidly than in the skin. Cells labeled in extracutaneous sites of proliferation appear rapidly in the blood, and their transit time through the peripheral blood compartment is short. Circulating Sezary cells may then be deposited in the skin where they resume proliferation at a low rate. Thus, while Sezary cells proliferate in both cutaneous and extracutaneous sites, proliferation appears to be more rapid in extracutaneous sites such as lymph nodes. This suggests that trials of systemic therapeutic approaches should be undertaken. 相似文献
68.
继续医学教育的目的是通过向医生提供最新的医学知识和技能,使医生在其整个职业生涯中,一直保持较高的医疗水平.但目前还没有充足的证据能证明继续医学教育活动的有效性,以及在继续医学教育活动中哪些教育方法和技术能最有效地传播和记忆医学知识.为了全面、系统地评估继续医学教育活动的有效性,以及了解不同的教育手段对医生知识、态度、技能、临床表现和临床效果的作用.美国约翰·霍普金斯大学医学院、美国医疗保健研究与质量管理署和美国胸科医师学会的专家共同进行了一项系统回顾性研究. 相似文献
69.
70.