全文获取类型
收费全文 | 462155篇 |
免费 | 64086篇 |
国内免费 | 26815篇 |
专业分类
耳鼻咽喉 | 5146篇 |
儿科学 | 7305篇 |
妇产科学 | 6399篇 |
基础医学 | 42877篇 |
口腔科学 | 11062篇 |
临床医学 | 77631篇 |
内科学 | 72649篇 |
皮肤病学 | 7232篇 |
神经病学 | 29503篇 |
特种医学 | 17098篇 |
外国民族医学 | 224篇 |
外科学 | 49527篇 |
综合类 | 70255篇 |
现状与发展 | 125篇 |
一般理论 | 31篇 |
预防医学 | 39652篇 |
眼科学 | 12675篇 |
药学 | 41437篇 |
435篇 | |
中国医学 | 24452篇 |
肿瘤学 | 37341篇 |
出版年
2024年 | 1585篇 |
2023年 | 9629篇 |
2022年 | 13662篇 |
2021年 | 20698篇 |
2020年 | 19290篇 |
2019年 | 13468篇 |
2018年 | 18655篇 |
2017年 | 18675篇 |
2016年 | 18270篇 |
2015年 | 24475篇 |
2014年 | 30924篇 |
2013年 | 30685篇 |
2012年 | 31716篇 |
2011年 | 35006篇 |
2010年 | 27968篇 |
2009年 | 26278篇 |
2008年 | 24520篇 |
2007年 | 23211篇 |
2006年 | 23432篇 |
2005年 | 21068篇 |
2004年 | 13954篇 |
2003年 | 13195篇 |
2002年 | 10884篇 |
2001年 | 10323篇 |
2000年 | 9438篇 |
1999年 | 10046篇 |
1998年 | 7297篇 |
1997年 | 6947篇 |
1996年 | 5883篇 |
1995年 | 5385篇 |
1994年 | 4209篇 |
1993年 | 2924篇 |
1992年 | 3155篇 |
1991年 | 2742篇 |
1990年 | 2288篇 |
1989年 | 2063篇 |
1988年 | 1771篇 |
1987年 | 1502篇 |
1986年 | 1282篇 |
1985年 | 959篇 |
1984年 | 612篇 |
1983年 | 564篇 |
1982年 | 361篇 |
1981年 | 361篇 |
1980年 | 231篇 |
1979年 | 214篇 |
1978年 | 192篇 |
1977年 | 167篇 |
1976年 | 117篇 |
1974年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
一氧化氮含量在急性脑梗死不同时期变化的临床意义 总被引:4,自引:0,他引:4
目的和方法为探讨急性脑梗死不同时期一氧化氮(NO)含量变化的临床意义,送检42例急性脑梗死患者不同时期的血清,采用Green改良法检测NO和以邻苯三酚自氧化法检测超氧化物歧化酶(SOD)含量,并配有30例正常对照。结果结果表明:脑梗死早期NO、SOD含量显著降低;急性期NO含量增高,并超过正常对照,而SOD含量进一步下降;脑梗死稳定期后,NO含量有所下降,接近正常水平,SOD含量增高,但仍低于正常。结论据上述结果提示,NO在急性脑梗死不同时期具有细胞毒性和组织保护双重作用,为临床寻求一种急性脑梗死的可能有效治疗方法提供了理论依据。 相似文献
992.
993.
In rabbit platelet rich plasma (PRP), 5-hydroxytraptamine (5-HT,0.03~3μmol/L) induced decrease in light transmission (DLT) dose-de pendently with centralization, as revealed by electron microscopy. However, 5-HT did not induced platelet aggregation and release reaction. 5-HT-induced DLT was inhibited by methysergide (0.3~30μmol/L), indomethacin (0.3~10μmol/L) and PGE_1 (0.01~0.3μmol/L) in a dose-dependent manner, but not EGTA(0.3~3mmol/L). Collagen(Coll), arachidonic acid (AA), adenosine diphosphate (ADP) and a stable thromboxane A2 analoge(STA_2) also induced DLT before aggregation by themselves, which was also inhibited by PGE_1, but not inhibited by EGTA except for Coll However,Coll-, AA-, STA_2-and ADP-induced DLT were reduced by pretreatment of PRP with 5-HT dose-depen-dently. The duration of DLT by Coll and AA were decreased from 151.4±5.93 sec and 15(?)38±0.60sec to 45.44±4.04 sec and 9.00±1.25 sec respectively ((?)±s(?) P<0.01), but not by ADP and STA_2, 3μmol/L of ADP-and 0.3μmol/L of STA_2-induced aggregation which was not accompanied with release reaction were enhanced by 5-HT pretreatment, but in those (Coil 5μg/ml, AA 100~200μmol/L and STA_2 1~3 μmol/L) with release reaction, the amount of adenosine triphosphate(ATP)were suppressed significantly (P<0.001) by 5-HT pretreatment without the effect on the magnitude of aggregation, The mobilization of cytosolic free calcium concentration ([Ca~(2+)]i) was observed after 5-HT treatment in single washed platelet, the results indicated that the basic level of [Ca~(2+)] i was 64.78±3.24nmol/L and this level was increased dose-dependently and significantly at 30 sec after administration of 5-HT and the time of peak value of [Ca~(2+)] i was at 90~100 sec.The similar time courses of suppression of ATP released during aggregation, in cases of Coll(5μg/ml), AA (200μmol/L) and STA_2(3μmol/L), by 5-HT were also found in the present experiment. 相似文献
994.
995.
996.
The palmar radiocarpal ligaments were studied with use of fifty-four dissected adult cadaver wrists and serial sections on twenty-three wrists from fetuses ranging in size from 23 to 230 millimeters crown-rump length. Three palmar radiocarpal ligaments were clearly identified: the radioscaphocapitate, long radiolunate, and short radiolunate ligaments. The radioscaphocapitate ligament originates from the radial styloid process and inserts into the radial aspect of the waist of the scaphoid, hemicircumferentially around the distal pole of the scaphoid and interdigitates with fibers from the palmar aspect of the triangular fibrocartilage complex just palmar to the head of the capitate, with only a minor insertion distally into the body of the capitate. The long radiolunate ligament originates just ulnar to the radioscaphocapitate ligament, being separated from it throughout its course by the interligamentous sulcus. The long radiolunate supports, but is separate from, the palmar aspect of the scapholunate interosseous ligament, and inserts into the radial half of the palmar surface of the lunate. The short radiolunate ligament, previously not described, originates just palmar to the lunate facet of the distal radius articular surface and inserts as a flat sheet of fibers into the proximal margin of the palmar surface of the lunate. Each ligament is intracapsular, enveloped within a continuous superficial fibrous stratum and deep synovial stratum. 相似文献
997.
998.
999.
Maritta Välimäki Lic. NSc RN & Helena Leino-Kilpi PhD RN 《Journal of advanced nursing》1998,27(1):204-212
In the context of an interview study concerned with self-determination in psychiatric patients, this paper describes the preconditions for and consequences of self-determination from the point of view of psychiatric patients themselves. The data were collected in semi-structured interviews with long-term psychiatric patients ( n =72) and analysed using the method of content analysis. Responses on the preconditions for self-determination were grouped into three categories: firstly, there were those who said that reference to self-determination in the case of psychiatric patients is nonsense; secondly, there were those who said that self-determination requires no preconditions; and thirdly, there were those who said that there are certain preconditions, such as the ability to think and make decisions, activity, obedience, and illness. Both positive and negative consequences were identified in situations where self-determination is maintained, but only negative consequences in situations where self-determination is lost. On the basis of these tentative results, self-determination seemed to be relevant in psychiatric nursing. We are continuing to develop and test an instrument for the evaluation of the opportunity for self-determination in clinical practice. 相似文献
1000.
目的:观察非程控降温、-80℃冻存的方法对自体外周血十细胞(APBSC)的保存效果。方法:以6%羟乙基淀粉(HES)、5%二甲基亚砜(DMSO)及4%人血白蛋白(ALB)的混合物为冷冻防护剂,将APBSC直接置于-80℃下保存,冻存前反复苏后测定APBSC的CFU-GM、BFU-E;观察移植后造血功能重建情况。结果:13例患者白细胞在十3~+7天下降至(0.0~0.1)×10/L,白细胞(0.0~0.2)×109/L持续时间3~6天,于+9~+11天恢复至1.0X109/L以上.中性粒细胞绝对值(ANC)于+9~+11天达到0.5X109/L。血小板在+3~+7天下降至(2.0~21)×109/L,于+8~+15天恢复至20×109/L以上。CFU-GM、BFU-E回大率分别为76.5%、78.4%。结论:非程控降温、-80℃冻存是一简便、经济、有效的自体外周血于细胞保存方法。 相似文献