全文获取类型
收费全文 | 1036篇 |
免费 | 80篇 |
国内免费 | 107篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 38篇 |
妇产科学 | 37篇 |
基础医学 | 139篇 |
口腔科学 | 32篇 |
临床医学 | 164篇 |
内科学 | 219篇 |
皮肤病学 | 11篇 |
神经病学 | 112篇 |
特种医学 | 88篇 |
外科学 | 79篇 |
综合类 | 44篇 |
预防医学 | 68篇 |
眼科学 | 6篇 |
药学 | 146篇 |
中国医学 | 5篇 |
肿瘤学 | 34篇 |
出版年
2021年 | 8篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 13篇 |
2016年 | 17篇 |
2015年 | 23篇 |
2014年 | 20篇 |
2013年 | 31篇 |
2012年 | 46篇 |
2011年 | 43篇 |
2010年 | 36篇 |
2009年 | 38篇 |
2008年 | 36篇 |
2007年 | 93篇 |
2006年 | 40篇 |
2005年 | 45篇 |
2004年 | 43篇 |
2003年 | 36篇 |
2002年 | 32篇 |
2001年 | 34篇 |
2000年 | 31篇 |
1999年 | 20篇 |
1998年 | 50篇 |
1997年 | 39篇 |
1996年 | 43篇 |
1995年 | 20篇 |
1994年 | 26篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 18篇 |
1990年 | 24篇 |
1989年 | 25篇 |
1988年 | 22篇 |
1987年 | 34篇 |
1986年 | 20篇 |
1985年 | 17篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 15篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 10篇 |
1969年 | 6篇 |
1967年 | 5篇 |
排序方式: 共有1223条查询结果,搜索用时 0 毫秒
91.
目的分析2005年1月~2011年12月在北京医院维持性血液透析死亡患者的病例特点和死亡原因。方法回顾性的检出维持血液透析大于3个月的死亡患者共83例,计算本中心从2005年起每年维持透析患者的死亡人数和死亡率;将死亡患者根据年龄分为3组,60岁以下中年组,60~79岁老年组和80岁以上高龄组,分析3组的人口学资料、有无糖尿病、透析龄和死亡原因等。结果从2005年起,北京医院每年维持透析患者的死亡率依次为11.00%,10.90%,8.30%。8.10%,10.10%,8.70%和6.34%;83例死亡患者中,男性49例,女性34例,平均年龄71.812.0岁(42岁~94)岁,中年组(小于60岁)14例,老年组(60~79)岁46例,高龄组(大于80)岁23例;3组患者在性别上无统计学差异。透析龄在中年组最长,平均77.2±73.0月,高龄组为44.0±35.5月,老年组透析龄最短,平均为33.2±28.1月;3组之间的差异有统计学意义。老年组患者糖尿病肾病居多;死亡原因在各组有明显的差别,中年组50%死于脑血管疾病,脑出血居多;高龄组56.50%死于感染中毒性休克。老年组死亡原因较复杂,死亡率超过10%的依次为感染中毒性休克、心肌梗死或心力衰竭、肿瘤、营养不良-炎症-动脉粥样硬化综合征(Malnutrition-inflammation-atherosclerosissyndrome,MIAsyndrome)和猝死。结论北京医院单中心血液透析死亡患者绝大多数为老年患者。年龄不是决定透析预后不良的主要危险因素,糖尿病是影响预后的重要因素,不同年龄组患者死亡原因不同,中年患者脑血管疾病多见,高龄患者感染中毒性休克常见,老年患者的死亡原因多样化,包括心脑血管疾病、感染、肿瘤和MIA综合征。± 相似文献
92.
A model of corrective gene transfer in X-linked ichthyosis 总被引:5,自引:0,他引:5
Freiberg RA; Choate KA; Deng H; Alperin ES; Shapiro LJ; Khavari PA 《Human molecular genetics》1997,6(6):927-933
Single gene recessive genetic skin disorders offer attractive prototypes
for the development of therapeutic cutaneous gene delivery. We have
utilized X-linked ichthyosis (XLI), characterized by loss of function of
the steroid sulfatase arylsulfatase C (STS), to develop a model of
corrective gene delivery to human skin in vivo. A new retroviral expression
vector was produced and utilized to effect STS gene transfer to primary
keratinocytes from XLI patients. Transduction was associated with
restoration of full-length STS protein expression as well as steroid
sulfatase enzymatic activity in proportion to the number of proviral
integrations in XLI cells. Transduced and uncorrected XLI keratinocytes,
along with normal controls, were then grafted onto immunodeficient mice to
regenerate full thickness human epidermis. Unmodified XLI keratinocytes
regenerated a hyperkeratotic epidermis lacking STS expression with
defective skin barrier function, effectively recapitulating the human
disease in vivo. Transduced XLI keratinocytes from the same patients,
however, regenerated epidermis histologically indistinguishable from that
formed by keratinocytes from patients with normal skin. Transduced XLI
epidermis demonstrated STS expression in vivo by immunostaining as well as
a normalization of histologic appearance at 5 weeks post-grafting. In
addition, transduced XLI epidermis demonstrated a return of barrier
function parameters to normal. These findings demonstrate corrective gene
delivery in human XLI patient skin tissue at both molecular and functional
levels and provide a model of human cutaneous gene therapy.
相似文献
93.
Pike VW Halldin C Nobuhara K Hiltunen J Mulligan RS Swahn CG Karlsson P Olsson H Hume SP Hirani E Whalley J Pilowsky LS Larsson S Schnell PO Ell PJ Farde L 《European journal of nuclear medicine and molecular imaging》2003,30(11):1520-1528
Single-photon emission tomography (SPET) and positron emission tomography (PET), when coupled to suitable radioligands, are uniquely powerful for investigating the status of neurotransmitter receptors in vivo. The serotonin subtype-4 (5-HT4) receptor has discrete and very similar distributions in rodent and primate brain. This receptor population may play a role in normal cognition and memory and is perhaps perturbed in some neuropsychiatric disorders. SB 207710 [(1-butyl-4-piperidinylmethyl)-8-amino-7-iodo-1,4-benzodioxan-5-carboxylate] is a selective high-affinity antagonist at 5-HT4 receptors. We explored radioiodinated SB 207710 as a possible radioligand for imaging 5-HT4 receptors in vivo. Rats were injected intravenously with iodine-125 labelled SB 207710, euthanised at known times and dissected to establish radioactivity content in brain tissues. Radioactivity entered brain but cleared rapidly and to a high extent from blood and plasma. Between 45 and 75 min after injection, the ratios of radioactivity concentration in each of 12 selected brain tissues to that in receptor-poor cerebellum correlated with previous measures of 5-HT4 receptor density distribution in vitro. The highest ratio was about 3.4 in striatum. SB 207710 was labelled with iodine-123 by an iododestannylation procedure. A cynomolgus monkey was injected intravenously with [123I]SB 207710 and examined by SPET. Maximal whole brain uptake of radioactivity was 2.3% of the injected dose at 18 min after radioligand injection. Brain images acquired between 9 and 90 min showed high radioactivity uptake in 5-HT4 receptor-rich regions, such as striatum, and low uptake in receptor-poor cerebellum. At 169 min the ratio of radioactivity concentration in striatum to that in cerebellum was 4.0. In a second SPET experiment, the cynomolgus monkey was pretreated with a selective 5-HT4 receptor antagonist, SB 204070, at 20 min before [123I]SB 207710 injection. Radioactivity in all brain regions was reduced almost to the level in cerebellum by 176 min after radioligand injection. These findings show that [123I]SB 207710 is an effective radioligand for imaging brain 5-HT4 receptors in vivo.For preliminary accounts of this work, see Pike VW et al., J Nucl Med 1998; 39 (Suppl):185; Eur J Nucl Med 1999; 26:991. 相似文献
94.
Frederick H Koh Jason MW Chua Joselyn LJ Tan Fung-Joon Foo Winson J Tan Sharmini S Sivarajah Leonard Ming Li Ho Bin-Tean Teh Min-Hoe Chew 《World journal of gastrointestinal surgery》2021,13(8):734-755
A growing body of evidence has demonstrated the prognostic significance of sarcopenia in surgical patients as an independent predictor of postoperative complications and outcomes. These included an increased risk of total complications, major complications, re-admissions, infections, severe infections, 30 d mortality, longer hospital stay and increased hospitalization expenditures. A program to enhance recovery after surgery was meant to address these complications; however, compliance to the program since its introduction has been less than ideal. Over the last decade, the concept of prehabilitation, or “pre-surgery rehabilitation”, has been discussed. The presurgical period represents a window of opportunity to boost and optimize the health of an individual, providing a compensatory “buffer” for the imminent reduction in physiological reserve post-surgery. Initial results have been promising. We review the literature to critically review the utility of prehabilitation, not just in the clinical realm, but also in the scientific realm, with a resource management point-of-view. 相似文献
95.
Antibody to a synthetic oligopeptide in subjects at risk for human immunodeficiency virus infection. 总被引:9,自引:7,他引:9 下载免费PDF全文
R S Smith R B Naso J Rosen A Whalley Y L Hom K Hoey C J Kennedy J A McCutchan S A Spector D D Richman 《Journal of clinical microbiology》1987,25(8):1498-1504
Detection of antibodies to human immunodeficiency virus (HIV) by enzyme-linked immunosorbent assay (ELISA) is the accepted method to screen blood products at risk to transmit infection. The presence of antibodies to HIV in 565 serum specimens from 274 patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex, symptomatic and asymptomatic subjects at risk for AIDS, and controls was determined with an ELISA that incorporates synthetic peptides (designated E32/E34) representing sequences in the envelope glycoprotein gp41. Of 105 specimens from patients with AIDS or AIDS-related complex, 3 specimens that were negative by commercially licensed ELISA and immunoblot test were similarly unreactive in the E32/E34 ELISA. For homosexual men with generalized lymphadenopathy, 186 specimens were positive by the E32/E34 ELISA and 63 specimens were negative. In comparison, with the licensed ELISA, 184 of these samples were positive and 65 samples were negative. The two samples that were positive in the E32/E34 ELISA but not the commercial kit were also positive by immunoblotting. Sequential sera from one individual who apparently underwent seroconversion according to the commercial assays were all positive by E32/E34 ELISA and immunoblotting. Thus, the ELISA with synthetic peptides is an extremely sensitive and specific test of antibody response to HIV and has not yet yielded a negative result with a Western blot (immunoblot)-confirmed antibody-positive serum. 相似文献
96.
Control of vascular reactivity in pregnancy 总被引:4,自引:0,他引:4
N F Gant P J Whalley R B Everett R J Worley P C MacDonald 《American journal of kidney diseases》1987,9(4):303-307
Human pregnancy is characterized by a blunted pressor responsiveness to vasopressor substances. This was first reported by Dieckmann and Michel in 1937 in experiments in which they measured vascular reactivity to the pressor effects of a crude preparation of vasopressin. Recently, this has been reported to occur in response to epinephrine, norepinephrine (NE), and angiotensin II (AII). Gant and associates reported that the increasing vascular sensitivity to infused AII not only was characteristic of women who developed pregnancy-induced hypertension, but in fact preceded the development of pregnancy-induced hypertension. Although a variety of factors may mediate this blunted pressor responsiveness, the most likely candidate appears to be the localized production within endothelium and/or vascular smooth muscle of prostaglandins. Indeed, administration of indomethacin or aspirin results in an increased sensitivity to infused AII in normotensive previously AII-refractory women. Administration of the steroid hormone 5 alpha-dihydroprogesterone reverses this apparent prostaglandin-mediated response. In addition, administration of the phosphodiesterase inhibitor, theophylline, results in a restoration of vascular refractoriness to infused AII in women with pregnancy-induced hypertension or in women destined to develop pregnancy-induced hypertension. Although a variety of known and possibly unknown compounds might also effect the control of vascular reactivity during human pregnancy, the prostinoids appear to play a pivotal role in mediation of control of vascular reactivity during human pregnancy. 相似文献
97.
98.
新复合纤维蛋白胶可注射性磷酸钙人工骨的理学特性 总被引:2,自引:0,他引:2
目的:检测纤维蛋白胶复合β-磷酸三钙/磷酸二氢钙复合人工骨材料的物理学性能,评价纤维蛋白胶对β-磷酸三钙/磷酸二氢钙骨水泥性能的影响,以及其作为注射型复合人工骨用于修复骨缺损的可行性。方法:实验于2006-12/2007-06在南方医科大学珠江医院中心实验室和华南理工大学生物材料实验室完成。①材料:β-磷酸三钙由上海瑞邦生物材料有限公司提供,磷酸二氢钙为东泰化工赠,纤维蛋白胶购自广州倍绣生物技术有限公司。②复合材料制备:将β-磷酸三钙/磷酸二氢钙骨水泥按3∶1的比例充分混合后,与纤维蛋白胶按凝固后的体积2∶1体积比混合,制成复合人工骨材料。③观察指标:测定复合材料的凝固时间,抗压强度,抗稀散性能,并用扫描电镜观察其煅烧前后的显微结构特征,以未加纤维蛋白胶的磷酸钙水泥为对照(CPC组)。结果:复合人工骨材料的平均初凝时间长于CPC组(P<0.004),终凝时间在初凝时间后2~4 min;复合材料的抗压强度为(14.72±1.81)MPa。复合材料较CPC组有良好的抗稀散性能,扫描电镜发现,纤维蛋白胶贯穿于磷酸钙水泥晶体间,并将磷酸钙水泥晶体紧密连接。煅烧后复合材料的孔径有增大,空隙率为57.28%,并且微孔之间有空隙互相贯通。结论:该骨水泥复合材料凝固时间符合临床操作的需要;抗压强度达到松质骨强度的要求;煅烧后磷酸钙水泥的空隙率明显提高,有利于材料的降解。 相似文献
99.
薄层扫描法测定黄芪生脉颗粒中黄芪甲甙含量 总被引:5,自引:0,他引:5
目的:制订黄芪生脉颗粒中黄芪甲甙含量测定方法。方法:双波长薄层扫描法,经乙酰洗涤、正丁醇提取和D101大乳吸附树脂柱层析法制备样品,以氯仿-甲醇-水(13:7:2)下层液为展开剂,检测波长为510nm,参比波长为700nm。结果:加标回收率平均为98.7%(RSD=2.0%,n=6),标准曲线r=0.9966,重复性RSD=1.4%(n=5),精密度RSD=2.0%(n=6)。结论:方法稳定、可靠 相似文献
100.
G A Whalley G D Gamble R N Doughty A Culpan L Plank S MacMahon N Sharpe 《Journal of hypertension》1999,17(4):569-574
BACKGROUND: Left ventricular mass is associated with body size, obesity and blood pressure. Echocardiography is routinely used to estimate this parameter, which is usually indexed to body surface area to allow comparisons to be made between individuals and groups of different body size. However, in obese subjects, using left ventricular mass indexed to body surface area may inappropriately normalize left ventricular mass. OBJECTIVES: The aim of this study was to investigate the relationships between left ventricular mass and body composition and to determine the best determinants of left ventricular mass. SUBJECTS AND METHODS: Echocardiography and dual-energy X-ray absorptiometry were performed in 106 subjects under primary care. Half were hypertensive subjects and the others were normotensive age- and sex-matched control subjects. Univariate correlations were studied between left ventricular mass and height, height1.5, height2.7, weight, body surface area, body mass index, waist: hip ratio, fat-free mass, bone mineral content and fat mass. Stepwise multiple linear regression was performed to determine the best determinants of left ventricular mass. RESULTS: Fat-free mass was correlated with left ventricular mass (r = 0.53, P = 0.0001) and was the only independent predictor of left ventricular mass (R2 = 0.30, P= 0.0001) by multivariate analysis. Fat mass did not correlate with left ventricular mass (r= -0.005, P= 0.96). Other measures of body size, including body surface area, waist: hip ratio, bone mineral content, weight, height, height 1.5, height2.7 and body mass index all were correlated with, but were not independent determinants of, left ventricular mass. CONCLUSIONS: Left ventricular mass is independently determined by fat-free mass but by no other measures of body size or composition. Specifically, left ventricular mass was neither correlated with nor determined by fat mass. None of the other measures of body size determined left ventricular mass. It may be more appropriate to index left ventricular mass to fat-free mass rather than to measures of body size which include fat mass. 相似文献