全文获取类型
收费全文 | 8219篇 |
免费 | 583篇 |
国内免费 | 202篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 189篇 |
妇产科学 | 302篇 |
基础医学 | 470篇 |
口腔科学 | 48篇 |
临床医学 | 1538篇 |
内科学 | 1632篇 |
皮肤病学 | 71篇 |
神经病学 | 395篇 |
特种医学 | 187篇 |
外科学 | 848篇 |
综合类 | 1425篇 |
预防医学 | 462篇 |
眼科学 | 169篇 |
药学 | 668篇 |
7篇 | |
中国医学 | 321篇 |
肿瘤学 | 208篇 |
出版年
2024年 | 12篇 |
2023年 | 99篇 |
2022年 | 161篇 |
2021年 | 298篇 |
2020年 | 309篇 |
2019年 | 261篇 |
2018年 | 255篇 |
2017年 | 282篇 |
2016年 | 318篇 |
2015年 | 285篇 |
2014年 | 526篇 |
2013年 | 577篇 |
2012年 | 469篇 |
2011年 | 510篇 |
2010年 | 461篇 |
2009年 | 387篇 |
2008年 | 415篇 |
2007年 | 395篇 |
2006年 | 386篇 |
2005年 | 341篇 |
2004年 | 259篇 |
2003年 | 237篇 |
2002年 | 202篇 |
2001年 | 173篇 |
2000年 | 138篇 |
1999年 | 117篇 |
1998年 | 105篇 |
1997年 | 105篇 |
1996年 | 71篇 |
1995年 | 85篇 |
1994年 | 71篇 |
1993年 | 65篇 |
1992年 | 62篇 |
1991年 | 66篇 |
1990年 | 43篇 |
1989年 | 41篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 29篇 |
1985年 | 39篇 |
1984年 | 39篇 |
1983年 | 39篇 |
1982年 | 35篇 |
1981年 | 37篇 |
1980年 | 26篇 |
1979年 | 22篇 |
1978年 | 24篇 |
1977年 | 18篇 |
1976年 | 14篇 |
1975年 | 6篇 |
排序方式: 共有9004条查询结果,搜索用时 342 毫秒
51.
目的探讨不孕不育及自发流产与染色体核型异常的关系,指导临床对这些疾病的诊断。方法采集922例生殖异常患者外周静脉血,进行淋巴细胞培养,常规方法收获细胞,低渗、固定、制片、经G显带处理、镜检,进行观察研究。结果922例患者共检出异常核型66例,总检出率7.16%。其中,易位21例,倒位21例,克氏综合征18例,X-三体综合征2例,Turner综合征伴X染色体缺失1例,Y染色体缺失1例,环状21号染色体1例,额外标记染色体1例,及常见染色体多态性大Y染色体63例,发生率13.35%。结论染色体异常是导致不孕不育及自发流产的重要原因之一,对生殖异常患者进行染色体检查可为临床诊断和优生优育提供依据。 相似文献
52.
F. Carmassi M. Morale F. De Negri M. Carrai 《Journal of molecular medicine (Berlin, Germany)》1995,73(2):89-93
Patients with liver failure can present both thrombotic and hemorragic complications because of the deficiency in coagulation factors and inhibitors (protein C and S, antithrombin III) and impairment of fibrinolytic balance. Here we report the case of a 63-year-old man with liver cirrhosis, recurrent thrombosis, and features of low-grade consumption coagulopathy, showing severe antithrombin III deficiency (about 30% of normal values). Treatment with antithrombin III (2000 U/day) and low doses of heparin (5000 U b.i.d.) was successful in modulating the coagulation system toward an antithrombotic effect. After discharge from hospital the ambulatory treatment with antithrombin III concentrates (2000 U twice a week) allowed the attainment of antithrombin III activity of about 60% and prevented the patient from recurrence of venous thrombosis.Abbreviations
AT-III
Antithrombin III
-
DIC
Disseminated intravascular coagulation
-
TAT complexes
Thrombin-antithrombin III complexes
-
PAI-1
Plasminogen activator inhibitor-1 相似文献
53.
This paper presents the first attempt to model the blood coagulation reactions in flowing blood. The model focuses on the
common pathway and includes activation of factor X and prothrombin, including feedback activation of cofactors VIII and V
by thrombin, and plasma inhibition of factor Xa and thrombin. In this paper, the first of two, the sparsely covered membrane
(SCM) case is presented. This considers the limiting situation where platelet membrane binding sites are in excess, such that
no membrane saturation or binding competition occurs. Under these conditions, the model predicts that the two positive feedback
loops lead to multiple steady-state behavior in the range of intermediate mass transfer rates. It will be shown that this
results in three parameter regions exhibiting very different thrombin production patterns. The model predicts the effect of
flow on steady-state and dynamic thrombin production and attempts to explain the difference between venous and arterial thrombi.
The reliance of thrombin production on precursor procoagulant protein concentrations is also assessed. 相似文献
54.
Zupi E Sbracia M Marconi D Alò P Atzei G Brazolin T Arduini D Romanini C 《American journal of reproductive immunology (New York, N.Y. : 1989)》2000,44(3):153-159
PROBLEM: Tumor necrosis factor-alpha (TNFalpha) is produced by the endometrium, and it has been shown that this cytokine has cyclic variations through the menstrual cycle. METHOD OF STUDY: In this study we assessed TNFalpha, estradiol and progesterone levels in the endometrium and serum of 21 patients with recent abnormal uterine bleeding (AUB). Eleven women showed histological diagnosis of endometrial hyperplasia, and ten women showed normal endometrium. RESULTS: The TNFalpha value in the serum of patients with hyperplasia and in normal endometrium did not show significant differences (64.8 +/- 21.4 vs 77.6 +/- 14.8 pg). The amounts of TNFalpha released by hyperplastic endometrial tissue were significantly higher than in control patients (258.8 +/- 78.0 vs 140.6 +/- 79.8 pg/g; P < 0.001). Immunohistochemistry of hyperplastic endometria showed a stronger staining than normal ones. Serum E2 levels in patients with hyperplastic endometrium were 49.5 +/- 31.6 ng/mL, and in controls were 107.3 +/- 66.0 ng/mL. The levels of estradiol released by hyperplastic endometria were significantly lower than in normal endometria (152.7 +/- 60.0 vs 279.9 +/- 178.7 ng/g; P < 0.003). CONCLUSIONS: Hyperplastic endometria produce higher amounts of TNFalpha with respect to controls. These findings may explain the frequent bleeding observed in the patients with endometrial hyperplasia, since TNFalpha promotes apoptosis and endometrial shedding. 相似文献
55.
Pregnancy following treatment of symptomatic myomas with laparoscopic bipolar coagulation of uterine vessels 总被引:7,自引:0,他引:7
Chen YJ Wang PH Yuan CC Yen YK Yang MJ Ng HT Chang SP Liu WM 《Human reproduction (Oxford, England)》2003,18(5):1077-1081
BACKGROUND: Laparoscopic bipolar coagulation of uterine vessels (LBCUV) has been employed for women with symptomatic uterine myomas, but its effect on subsequent pregnancy has not been characterized. METHODS: Four-hundred and twenty-three women entered the study between March 1999 and December 2001. Of these, 142 women (33.6%) were under the age of 40 years at the time of LBCUV, 36 of whom (36/142, 25.3%) were sexually active without contraception. In a prospective study of 142 patients (<40 years old) undergoing LBCUV for symptomatic myomas, 15 women became pregnant (17 total pregnancies) and were evaluated by physical and ultrasound examinations. RESULTS: The volume of the dominant myoma was 117.4 +/- 118.4 and 36.8 +/- 56.8 cm(3) before and after LBCUV respectively. Volume of the dominant myoma after pregnancy was 46.2 +/- 76.7 cm(3) (mean +/- SD). There was a significant difference in myoma volume before and after LBCUV (P = 0.002), but no significant difference in myoma volume when comparing post-partum size with post-LBCUV size (P = 0.269). Pregnancy outcomes included seven miscarriages in the first trimester and one premature rupture of membrane (PPROM). Although the other pregnancies were regarded as uncomplicated, only two women were delivered of normal neonates as the other seven pregnancies were terminated secondary to patient request. CONCLUSIONS: The pregnancy and term pregnancy rates in sexually active women without contraception were 41.6% (15/36) and 5.6% (2/36) respectively. Because a relatively high rate (7/17, 41.2%) of early miscarriages was observed, we recommend that this procedure be employed only for women who do not desire additional children. 相似文献
56.
目的探讨染色体核型异常与生育异常的关系。方法对2004年5月至2007年4月到吉林大学特殊疾病检测站进行遗传咨询的816例患者进行外周血淋巴细胞培养,进行染色体核型分析。结果受检的生育异常患者为816例,核型异常99例,异常率为12.13%。其中常染色体异常22例,占22.22%,性染色体异常46例,占46.46%,嵌合体异常31例占31.31%。结论染色体异常是生殖异常的重要原因之一,对生育异常患者进行染色体检查可为临床诊断和优生优育提供依据。 相似文献
57.
再生障碍性贫血患者淋巴细胞表型变化 总被引:7,自引:0,他引:7
目的:研究再生障碍性贫血(AA)患者骨髓(BM)及外周血(PB)淋巴细胞及其活化相关分子的表达及临床意义。方法:采用单色和双色免疫荧光标记法,流式细胞仪分析AA患者的BM和PB中淋巴细胞膜分子的表达。结果:AA患者BM和BP中CD8^ 细胞增加,CD4/CD8比例下降,BM在CD25^ 细胞和HLA-DR^ 细胞增多,急性AA增加尤为显著(P<0.01),BM中CD16^ 或CD56^ 细胞也明显增多(P<0.05),双标记分析提示T细胞主要为CD8^ 细胞:急性AA患者CD8^ -CD25^ 细胞显著增多(P<0.01),AA患者BM中淋巴细胞活化相关分子表达增多,尤其4-1BB^ ,CD95L^ 和CD40L+细胞显著增多(P<0.01),结论:AA患者BM中淋巴细胞活化相关膜分子增多,是AA免疫功能异常及最终导致造血功能衰竭的原因之一。 相似文献
58.
目的:研究内源性高甘油三酯血症(HTG)患血浆极低密度脂蛋白(VLDL)、低密度脂蛋白(LDL)及高密度脂蛋白(HDL)是否发生了氧化修饰及其对血凝的影响。方法:对2l例内源性高甘油三酯血症患与2l例年龄性别相近的正常人的血脂、脂质过氧化物进行了分析。用一次性密度梯度超速离心法分离血浆VLDL、LDL及HDL,测定这三种脂蛋白的234nm光吸收、相对电泳迁移率(REM)和硫代巴比妥酸反应物质(TBARS),分别将这三种脂蛋白加入由正常人新鲜混合血浆构成的反应系统中,按试剂盒分别测定凝血酶原时间(PT)及活化部分凝血酶原时间(APIT)。结果:内源性HTG患血浆TG含量平均升高2.73倍,HDLC下降l.7l倍,同时LPO升高1.22倍;HTG组VLDL、LDL及HDL的REM、234nm光吸收值、TBARS含量均较对照组显增加(P<0.01),表明内源性HTG患血浆VLDL、LDL及LDL均发生了氧化修饰生成Ox—VLDL、Ox-LDL.PT及APTT在分别加入HTG组的VLDL、LDL及HDL后均比加入相应正常组脂蛋白明显缩短(P均<0.05)。相关分析表明,HTG组血浆VLDL及HDL相对电泳迁移率(REM)与PT呈负相关(P<0.01)。结论:HTG患血浆VLDL、LDL及HDL发生了氧化修饰,并使PT及APTT明显缩短。 相似文献
59.
目的 :探讨不同病情硬肿症播散性血管内凝血 (DIC)的出凝血功能改变 ,为合理治疗提供理论依据。方法 :比较观察组 10 0例和对照组 5 0例 5项出凝血指标检测结果。结果 :观察组不同病情之间比较 :凝血酶原时间 ,3P试验 ,血小板计数和外周血红细胞形态无显著性差异 (P均 >0 0 5 ) ;试管法凝血时间比较 ,有显著性差异 (P <0 0 5 )。观察组与对照组 5项指标比较有非常显著性差异 (P <0 0 1)。结论 :新生儿硬肿症存在播散性血管内凝血的出凝血功能改变 ,病情越重改变越明显 ,越易合并DIC、肺出血 ,病死率也越高 ,硬肿症早期血液多呈现高凝状态 ,DIC的晚期多呈现低凝状态。早期肝素治疗 ,不仅可改变血液的出凝血状态 (高凝状态 ) ,而且是防治DIC ,肺出血 ,提高治愈率的有效途径。治疗硬肿症加强综合支持疗法 ,尤其是维持内环境稳定纠正酸中毒切不可忽视 ,否则肝素在酸性环境中灭活失效 相似文献
60.
目的:探讨争民性早幼粒细胞型白血病的止血凝血变化及其对临床意义的影响。方法:应用放射免疫法、单抗酶联免疫法和发色底物法,对21例初入院的急性早幼粒细胞型白血病(APL)患者于化疗前和获得完全缓解后,进行血浆血栓烷(TXB2)、血管性假血友病因子抗原(VWF:Ag)、抗凝血酶原-Ⅲ(AT-Ⅲ)以及纤维蛋白原(Fg)、凝血酶原时间(PT)等检测,并与正常对照观察。结果:化疗前21例患者血浆TXB2、WVF:Ag、AT-Ⅲ、PT、Fg水平与正常对照比较有明显不同(分别P<0.05,P<0.01,P<0.01,P<0.01,P<0.01),经治疗后获得完全缓解的13例患者血浆TXB2、VWF:Ag、AT-Ⅲ、PT、Fg水平与化疗前对照亦有明显不同(分别P<0.05,P<0.01,P<0.01,P<0.01,P<0.01)。结论:APL患者的止血凝血障碍由多种因素形成,而且患者止血凝血障碍的 病理变化是普遍存在的。 相似文献