全文获取类型
收费全文 | 8675篇 |
免费 | 574篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 477篇 |
妇产科学 | 359篇 |
基础医学 | 747篇 |
口腔科学 | 19篇 |
临床医学 | 2209篇 |
内科学 | 1855篇 |
皮肤病学 | 18篇 |
神经病学 | 85篇 |
特种医学 | 115篇 |
外科学 | 1101篇 |
综合类 | 1153篇 |
预防医学 | 466篇 |
眼科学 | 15篇 |
药学 | 457篇 |
7篇 | |
中国医学 | 119篇 |
肿瘤学 | 168篇 |
出版年
2023年 | 211篇 |
2022年 | 185篇 |
2021年 | 406篇 |
2020年 | 318篇 |
2019年 | 293篇 |
2018年 | 269篇 |
2017年 | 334篇 |
2016年 | 293篇 |
2015年 | 313篇 |
2014年 | 535篇 |
2013年 | 542篇 |
2012年 | 425篇 |
2011年 | 462篇 |
2010年 | 383篇 |
2009年 | 380篇 |
2008年 | 353篇 |
2007年 | 406篇 |
2006年 | 335篇 |
2005年 | 342篇 |
2004年 | 288篇 |
2003年 | 224篇 |
2002年 | 224篇 |
2001年 | 231篇 |
2000年 | 202篇 |
1999年 | 157篇 |
1998年 | 165篇 |
1997年 | 132篇 |
1996年 | 120篇 |
1995年 | 107篇 |
1994年 | 106篇 |
1993年 | 74篇 |
1992年 | 69篇 |
1991年 | 55篇 |
1990年 | 41篇 |
1989年 | 46篇 |
1988年 | 36篇 |
1987年 | 27篇 |
1986年 | 26篇 |
1985年 | 33篇 |
1984年 | 37篇 |
1983年 | 17篇 |
1982年 | 26篇 |
1981年 | 22篇 |
1980年 | 21篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1974年 | 9篇 |
1973年 | 11篇 |
排序方式: 共有9387条查询结果,搜索用时 15 毫秒
31.
J. Moji A. Nicák M. Troák I. Kozák L. Mirossay 《Comparative Haematology International》1999,9(2):83-85
Erythrocyte microrheology changes were measured by cation-osmotic haemolysis (COH) in healthy donors, patients with ischameic
stroke, and patients who died within four days after a stroke. COH in patients with stroke was significantly decreased in
comparison with that from healthy donors. In patients who died, COH was significantly decreased compared to patients who survived.
The relationship between cationosmotic haemolysis and erythrocyte deformability is discussed. 相似文献
32.
Clark P. Holz P. Booth R. Jakob-Hoff R. Cooper D.W. Boardman W.S. Parry B.W. Norman R.J. 《Comparative clinical pathology》2003,12(1):11-16
Blood was collected from 31 Parma wallabies from five different captive populations. The morphology of erythrocytes, leucocytes
and platelets was similar to that previously described for macropodids. The effects of location (population), anaesthesia
and analyser on the haematological characteristics of the wallabies were considered. Location had an affect on many of the
values, anaesthesia affected some of the leucocyte values, and analyser had little effect.
Received: 22 November 2002 / Accepted 13 February 2003
Acknowledgements We thank Mrs R. Power, Ms S. Bayliss, Ms T. Smith and Mrs P. Slack for technical assistance, Mr D. Hopcroft for assistance
with electron microscopy and Mr D. Hedderly for performing the statistical analyses. 相似文献
33.
Molecular and serological evaluation of surface antigen negative hepatitis B virus infection in blood donors from Venezuela 总被引:2,自引:0,他引:2
Gutiérrez C Devesa M Loureiro CL León G Liprandi F Pujol FH 《Journal of medical virology》2004,73(2):200-207
Surface antigen negative hepatitis B virus (HBV) infection was evaluated in Venezuela, by molecular characterization of blood samples positive for antibodies to core antigen (anti-HBc) and negative for surface antigen (HBsAg) in blood donors (residual infections). HBV DNA was found in 11/258 samples (4.3%), and was significantly associated with high levels of anti-HBc antibodies (>25 UI/ml, P < 0.05), while no correlation was found between the presence of HBV DNA and the levels of anti-HBs. Synonymous and non-synonymous mutations were found in the HBV surface region (but not vaccine escape mutants) and in the precore/core region (precore mutants in 2/7 samples and 33-45 bp deletions near the N-terminal core region in 4/19 samples). While HBV genotype F prevails among HBsAg positive samples from blood donors in Venezuela, residual infection isolates were mainly genotypes A and D. Phylogenetic analysis of viral surface and core region revealed discrepancies in genotype designation in 6/9 samples, suggesting the presence of mixed infection or recombination. In conclusion, HBV residual infection in Venezuela does not seem to be frequently observed in HBV genotype F. This type of infection is frequently associated with variants exhibiting mutations in the surface gene that might be affecting the correct recognition by commercial tests, with precore mutants and with core internal deletions. These variants do not seem to cause severe liver disease, and on the contrary, were found circulating at low viremia. 相似文献
34.
A subcellular fraction enriched in erythrocyte membranes has been isolated from rhesus monkey erythrocytes infected with Plasmodium knowlesi. Infected cells were lysed by centrifugation through a zone of hypotonic buffer and membranes isolated by equilibrium density gradient centrifugation in the same tube. The purified membrane fraction was shown to include the erythrocyte surface membrane by several methods: electron microscopy, identification of Coomassie Blue stained erythrocyte membrane proteins, identification of band 3 with a monoclonal antibody, and identification of radioiodinated cell surface proteins. The resulting ghosts were shown to be specifically reactive with monkey sera against the variant surface antigens of P. knowlesi by indirect immunofluorescence and membrane agglutination. No reactivity was seen with a monoclonal antibody (13C11) against the intracellular schizont surface. A number of metabolically labelled parasite proteins were enriched in this membrane function, including peptides of 277, 208, 173, 153, 134, 109, 80, 60 and 48 kDa and the variant surface antigens of variable molecular mass (180-207 kDa). These proteins were distinct from the major parasite proteins of total infected erythrocytes and isolated merozoites. The major glucosamine labelled glycoprotein of the internal schizont (230 kDa) was not found in this fraction. Moreover, no fragment of this parasite glycoprotein was found in this membrane fraction, indicating that no part of this molecule is transported to the erythrocyte surface. In contrast, the variant antigen of P. knowlesi, known to be on the erythrocyte surface, could be readily identified as peptides unique to specific cloned parasite lines. We propose that the other nine parasite proteins found within this membrane fraction represent a starting point for the identification of other parasite proteins transported to the surface membrane of the infected erythrocyte. 相似文献
35.
Intraplacental choriocarcinoma is very rare, and is usually found only after maternal and fetal metastatic disease is identified. The purpose of this case report is to review the incidence and findings of intraplacental choriocarcinoma. A term placenta was investigated because the newborn was born with severe anemia (Hb 3.0 g/dL). A 2 cm nodule was noted on the surface of the amniotic membrane and grossly resembled an infarction. The tumor was examined microscopically with immunohistochemical staining for the alpha- and beta-human chorionic gonadotropin (alpha-hCG, beta-hCG) subunits, human placental lactogen (hPL) and Ki-67. Microscopically, the tumor consisted of necrotic areas with proliferation of atypical trophoblastic cells and destruction of the villi and capillaries. The cells were positive for the alpha-hCG, beta-hCG subunits, hPL and Ki-67, consistent with intraplacental choriocarcinoma. The mother and newborn were investigated for the presence of metastatic disease. Computed tomography scans and magnetic resonance imaging of the mother and infant were negative for metastatic disease. Choriocarcinoma, limited only to the placenta with no evidence of metastatic disease is very rare. Primary intraplacental choriocarcinoma may frequently be overlooked or missed, and choriocarcinoma may possibly arise in the placenta more often than in retained or persistent trophoblast following pregnancy. 相似文献
36.
G L Sussman R P Harvey A L Schocket 《The Journal of allergy and clinical immunology》1982,70(5):337-342
Delayed pressure urticaria (DPU) is a poorly understood syndrome. We describe 17 patients with DPU. Chronic urticaria was present in 94%. All had negative challenges for immediate demographism and cold urticaria. DPU was induced with a pressure challenge on the shoulder of 15 pounds for 15 min. Average onset of pressure lesions after challenge was 6.5. Lesions were painful, not pruritic, peaked at 9 hr, and disappeared by 24 to 48 hr. Fever, chills, and/or arthralgias occurred in 78%. Positive laboratory abnormalities included leukocytosis in 20% and elevated erythrocyte sedimentation rate in 37.5%. Skin biopsies of lesions showed perivascular round cell infiltrates and negative immunofluorescence. Urticaria responded to antihistamines, but not aspirin, in 100% of patients, while pressure lesions improved with nonsteroidal anti-inflammatory drugs (NSAID), but not antihistamines, in 80% of patients. Both urticaria and DPU were controlled with prednisone, which was necessary in 87.5% of patients. A severe nonremitting course was noted in 7%, 40% had a moderate remitting course requiring intermittent prednisone, and 53% had a mild remitting disease requiring no medication or antihistamines and/or NSAID only. We conclude that DPU is more common than previously appreciated and likely involves mediators other than histamine, possibly the prostaglandin system. 相似文献
37.
为了了解内外科输血前四项检查结果的情况,笔者总结了从2000年11月~2001年5月的外科420人和内科69人因各种疾患需要输血的住院患者检查结果外科、内科乙肝六项检查含HBsAg阳性各为27例、8例,阳性率分别为6.4%(27/420)、11.6%(8/69);抗HCVIgG阳性各为12例、6例,阳性率分别为2.9%(12/420)、8.7%(6/69);梅毒抗体阳性分别为3例、2例;外科HIV抗体全阴性,内科阳性2例.提示输血前四项检查很有必要,以减少不必要的由输血引起的医疗纠纷. 相似文献
38.
C. R. Evans R. Jones G. Phillips G. Greene M. Phillips R. Morris-Clarke 《Anaesthesia》2021,76(5):639-646
Cardiac surgical patients with anaemia experience increased morbidity and mortality. Iron deficiency is the most common cause of pre-operative anaemia in this group. We designed and implemented the Cardiff Pathway, a pre-assessment and treatment pathway to identify cardiac surgical patients with anaemia and iron deficiency. Patients identified with anaemia and/or iron deficiency (Hb < 130 g.l-1 and ferritin < 100 μg.l-1) were offered intravenous iron infusion 20 mg.kg-1 pre-operatively. Treatment success was defined as Hb ≥ 130g.l-1 on the day of surgery. We analysed data from 447 patients: 300 (67%) were not anaemic; 75 (17%) were anaemic and treated with intravenous iron; and 72 (16%) were anaemic and not treated. Haemoglobin concentration increased in successfully treated anaemic patients by a mean (95%CI) of 17 (13–21) g.l-1 and they received a median (IQR [range]) of 0 (0–2 [0–15]) units of blood peri-operatively. Transfusion was avoided in 54% of the successfully treated anaemic patients, which was significantly more than the unsuccessfully treated anaemic (22%, p = 0.005) and untreated anaemic (28%, p = 0.018) patients and similar to non-anaemic patients who received a median (IQR [range] of 0 (0–1 [0–16])) units of blood and, 63% avoided transfusion). Mean (95%CI) Hb fell between pre-assessment and surgery in the untreated anaemic (-2 (0 to -4) g.l-1) and non-anaemic groups (-2 (-1 to -3) g.l-1). Twenty-one (7%) of the non-anaemic group became newly anaemic waiting for surgery. The Cardiff Pathway reliably identified patients with anaemia and iron deficiency. Anaemic patients who had their Hb restored to normal after treatment required less blood peri-operatively and over half of them required no transfusion at all. 相似文献
39.
Emrah Caliskan Salih Suha Koparal Volkan Igdir Emre Alp Ozgur Dogan 《Foot and Ankle Surgery》2021,27(4):457-462
BackgroundThe measurement of plantar fascia thickness with ultrasonography can be used for both for diagnosis and as a response-to-treatment parameter in plantar fasciitis. Furthermore, with the recent studies, red cell distribution width may be used as an inflammatory marker. Aim of this study is to investigate the association of red cell distribution width and ultrasonography on diagnosis and monitoring of treatment in patients with plantar fasciitis.MethodsClinically diagnosed 102 patients with plantar fasciitis between the dates January 2016 to July 2018 were analysed. Hemogram, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and plantar fascial ultrasonography were obtained on initial evaluation and in 1 month, 2 months and 3 months of the standard nonoperative treatment; American Orthopaedic Foot & Ankle Hindfoot Score (AOFAS) and Visual Analog Scale (VAS) scores were recorded. Posthoc and multivariate logistic regression analysis were used for statistical analysis on SPSS 21.0.ResultsRed cell distribution width was correlated with plantar fascia thickness by the end of the 1 month (r = 0.26, P = .013). Female sex, BMI over 30 kg/m2, higher red cell distribution width and higher plantar fascia thickness were associated with plantar fasciitis on initial evaluation. Higher red cell distribution width together with higher plantar fascia thickness were also found to be a risk factor for both on initial evaluation and 1 month after treatment in plantar fasciitis.ConclusionThis study shows that association of red cell distribution width and plantar fascia thickness can be not only a diagnostic predictor but also an indicator of treatment response in plantar fasciitis.Level of clinical evidenceLevel IV 相似文献
40.
本文用流槽系统,定量地研究年龄对健康人红细胞与培养的人脐静脉内皮细胞粘附的影响。在本研究所选用的两个年龄阶段,其结果显示:①红细胞自身特性的改变对粘附的数目没有明显的影响,但随着年龄的增加粘附的强度增大;②在自体血浆存在时,随着年龄的增加红细胞与内皮细胞的粘附增强。这可能与心脑血管病如心肌梗塞、脑血栓形成等多发生在40岁以上的中老年人有关。 相似文献