全文获取类型
收费全文 | 48877篇 |
免费 | 2911篇 |
国内免费 | 1085篇 |
专业分类
耳鼻咽喉 | 246篇 |
儿科学 | 1111篇 |
妇产科学 | 585篇 |
基础医学 | 5525篇 |
口腔科学 | 456篇 |
临床医学 | 6547篇 |
内科学 | 6787篇 |
皮肤病学 | 357篇 |
神经病学 | 2200篇 |
特种医学 | 2337篇 |
外国民族医学 | 1篇 |
外科学 | 4701篇 |
综合类 | 7794篇 |
现状与发展 | 4篇 |
预防医学 | 4137篇 |
眼科学 | 381篇 |
药学 | 6199篇 |
20篇 | |
中国医学 | 2532篇 |
肿瘤学 | 953篇 |
出版年
2023年 | 540篇 |
2022年 | 1044篇 |
2021年 | 1687篇 |
2020年 | 1443篇 |
2019年 | 1189篇 |
2018年 | 1278篇 |
2017年 | 1266篇 |
2016年 | 1393篇 |
2015年 | 1487篇 |
2014年 | 3250篇 |
2013年 | 3401篇 |
2012年 | 3052篇 |
2011年 | 3322篇 |
2010年 | 2577篇 |
2009年 | 2451篇 |
2008年 | 2471篇 |
2007年 | 2304篇 |
2006年 | 2115篇 |
2005年 | 1826篇 |
2004年 | 1533篇 |
2003年 | 1394篇 |
2002年 | 1174篇 |
2001年 | 961篇 |
2000年 | 954篇 |
1999年 | 782篇 |
1998年 | 696篇 |
1997年 | 678篇 |
1996年 | 604篇 |
1995年 | 608篇 |
1994年 | 532篇 |
1993年 | 503篇 |
1992年 | 404篇 |
1991年 | 380篇 |
1990年 | 319篇 |
1989年 | 265篇 |
1988年 | 309篇 |
1987年 | 259篇 |
1986年 | 222篇 |
1985年 | 251篇 |
1984年 | 282篇 |
1983年 | 166篇 |
1982年 | 205篇 |
1981年 | 192篇 |
1980年 | 179篇 |
1979年 | 145篇 |
1978年 | 132篇 |
1977年 | 111篇 |
1976年 | 78篇 |
1975年 | 70篇 |
1973年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Hui Liu Tetsuzo Agishi Hideiku Suga Yutaro Hayasaka Satoshi Teraoka Kazuo Ota 《Artificial organs》1995,19(4):324-327
Abstract: Prevention of hyperacute rejection is a difficult and unsolved problem in xenotransplantation. Natural antibodies and complement activation have been known to play an important role in the xenotransplantation between discordant species pairs. In the present study, total blood exchange (TBE) was performed with pyridox-alated-hemoglobin-polyoxyethylene conjugate (PHP) solution (Ajinomoto Co., Inc., Kawasaki, Japan) before cardiac xenotransplantation in order to remove the immunoglobulins and prolong xenograft survival time. Guinea pigs and rats were used as the discordant species combination for donor and recipient. Two groups were established: Group 1, untreated control (n = 8) and Group 2, TBT with PHP solution (n = 8). The exchange blood transfusion was carried out at the rate of 15–20 ml/h utilizing PHP solution using a blood pump. After the blood exchange was processed, hematocrit (Ht) levels dropped to 4 or 5%, and a cardiac xenotransplantation was performed within 24 h. The levels of serum IgA, IgM, and IgG were decreased to less than 25, 25, and 10% of the base line, respectively, after blood exchange. A mean xenograft survival time in Group 2 was prolonged to 472 ± 74 min and to 10.4 ± 1.8 min in Group 1 (p < 0.01). A titer of the anti-guinea pig lymphocytotoxic antibody in rat serum was decreased to almost nil. The data from this study suggest that total blood exchange with PHP solution may be useful in preoperative removal of xenograft antibodies in xenotransplantation. 相似文献
92.
H. Inaba M.D. J. Sato H. Uchida M. Sakurada T. Ohwada T. Mizuguchi 《Acta anaesthesiologica Scandinavica》1988,32(5):374-378
Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with unilateral lung injury induced by the introduction of hydrochloric acid, F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at periods of 6 min, and conventional PEEP (C-PEEP) with an optimized EEP of 1.0 kPa, were each applied for 30 min. F-PEEP produced a significantly greater improvement of PaO2 and intrapulmonary shunt (QS/QT) than C-PEEP, and at the low EEP phase, the greatest improvement accompanied by an increased dynamic compliance and a large cardiac output was obtained. These results suggest that F-PEEP provides a useful mode of artificial ventilation for the treatment of unilateral lung injury. 相似文献
93.
Brigden Geoffrey Zanelli Giussepe Lahiri Avijit Raftery Edward 《European journal of nuclear medicine and molecular imaging》1990,16(11):795-799
A new, single bolus method of in vivo blood pool imaging using a technetium Tc99m phosphine isocyanide complex (DEPIC) which binds to pre-albumin was evaluated in volunteers (n=4) and patients (n=20). DEPIC was assessed for its safety and possible drug interactions. Its duration of action and quality of ventriculography were compared with imaging using standard in vivo red cell labelling (PYP) during two 3-h scanning periods 1 week apart. DEPIC had a mean plasma halflife of 3.3 h. The count rate over the left ventricle was initially 42% higher with DEPIC than with PYP. However, removal of DEPIC by the liver resulted in equivalent count rates by 1 h, and by 3 h PYP count rates were 22% higher than DEPIC. Immediately post injection mean (SD) difference in the left ventricular ejection fraction between the two methods was 2.4% (7.7%). Satisfactory DEPIC scans were obtained up to 2 h post injection, but by 3 h there was a mean difference of 13% (11.3%). DEPIC was found to be a safe alternative to red all labelling for blood pool angiography, suitable for routine work. The single bolus methodology and high initial count rates offer improved efficiency and a capability for truly emergency scanning. 相似文献
94.
林丽星 《兰州大学学报(医学版)》1998,24(3):33-35
目的:探讨新生儿窒息后血糖,血气,心肌酶(谷草转氨酶,磷酸肌酸激酶及乳酸氢酶)的变化及其相关性。方法;血糖采用微量血糖仪测定,血气用足跟动脉化毛细血管法,心肌酶采用酶偶联连续监测,相关分析采用多元线性回归法。结果:低血糖8例,高血糖3例;36例均存在着不同程度的低氧血症和混合性酸中毒;22例心肌酶活性增高。血糖值与日龄呈负相关,与体温呈正相关,心肌酶活性男性高于女性,各酶之间有一定的相关性,但并非 相似文献
95.
为探讨冠心病患者血糖与微量元素的关系,用电感耦合等离子体原子发射光谱法测定了78例冠心病患者的6种微量元素变化,并与血糖做相关分析.结果冠心病患者高血糖组与正常血糖组相比,血清铁、铅、镉显著增高,锌和铬显著降低,P<005或001,铜无显著性差异;血糖与血清铁、铅呈显著性正相关,与血清铬、锌呈显著负相关,而与铜、镉相关不显著.表明部分微量元素的不平衡构成对冠心病的危险因子———高血糖的促发作用,调整人群中微量元素的不平衡状态,对减少冠心病及糖尿病的发生可能有利 相似文献
96.
Rh血型不合新生儿溶血病检测方法及应用 总被引:3,自引:0,他引:3
产前检测Rh,D因子及抗人球蛋白(coombs)试验是必要的。测定Rh,D因子及抗D滴度使用木瓜酶方法。通过对11261例孕妇常规检查Rh,D因子,发现D阴性74例。Rh,D阴性妇女占6.5‰。22例Rh,D阴性的孕妇所分娩的新生儿均为Rh,D阳性。其中2例孕妇血清抗D滴度为1∶32,病情严重,宫内输血无效,胎死宫内。初产妇13例,占59%。活产20例,存活率90%。Rh因子及抗人球蛋白试验方法简便、易行,一般医院均可进行。对有流产史、输血史的孕妇检查Rh因子是十分必要的。在有条件的医院,对Rh,D阴性的产妇分娩Rh,D阳性的新生儿之后,产妇应预防性注射抗D免疫球蛋白 相似文献
97.
Jim-Shoung Lai T.-N. Wu Saou-Hsing Liou Chen-Yang Shen Chiam-Fang Guu Kquei-Nu Ko Chi. Hsueh-Yun P.-Y. Chang 《International archives of occupational and environmental health》1997,69(4):295-300
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship
between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were
measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics
and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear
regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol
consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although
PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based
on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient
lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood
lead levels in lead battery factories.
Received: 28 May 1996/Accepted: 30 August 1996 相似文献
98.
99.
本研究从急性低氧对移居海平面后藏族的体力活动能力的影响来探索藏族的高原低氧适应机制。结果揭示藏族的最大体力负荷强度没有显著下降,最大氧耗和氧脉搏也没有明显变化,动脉血氧饱和度明显高于汉族,这更显示藏族对高原低氧适应机制有独特之处。推测可能是藏族在氧的摄取、传递和释放过程比汉族更有利于对高原低氧环境的适应。 相似文献
100.
目的:解释血压在毛细血管前阻力血管中下降最快的原因。方法:利用物理模型简化复杂的心血管系统。结果:全身所有的微、小动脉段“并联”,全身所有的毛细血管段“并联”。结论:微、小动脉段的总流阻最大、使俐血压在微、小动脉中下降最快。 相似文献