全文获取类型
收费全文 | 26490篇 |
免费 | 2141篇 |
国内免费 | 315篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 589篇 |
妇产科学 | 388篇 |
基础医学 | 4560篇 |
口腔科学 | 406篇 |
临床医学 | 2690篇 |
内科学 | 1886篇 |
皮肤病学 | 171篇 |
神经病学 | 4335篇 |
特种医学 | 296篇 |
外国民族医学 | 1篇 |
外科学 | 881篇 |
综合类 | 3788篇 |
一般理论 | 1篇 |
预防医学 | 5320篇 |
眼科学 | 67篇 |
药学 | 2718篇 |
13篇 | |
中国医学 | 344篇 |
肿瘤学 | 424篇 |
出版年
2023年 | 365篇 |
2022年 | 600篇 |
2021年 | 1227篇 |
2020年 | 989篇 |
2019年 | 821篇 |
2018年 | 783篇 |
2017年 | 876篇 |
2016年 | 929篇 |
2015年 | 920篇 |
2014年 | 1743篇 |
2013年 | 2128篇 |
2012年 | 1512篇 |
2011年 | 1688篇 |
2010年 | 1237篇 |
2009年 | 1237篇 |
2008年 | 1241篇 |
2007年 | 1180篇 |
2006年 | 1074篇 |
2005年 | 871篇 |
2004年 | 731篇 |
2003年 | 685篇 |
2002年 | 548篇 |
2001年 | 416篇 |
2000年 | 324篇 |
1999年 | 309篇 |
1998年 | 264篇 |
1997年 | 242篇 |
1996年 | 203篇 |
1995年 | 190篇 |
1994年 | 171篇 |
1993年 | 151篇 |
1992年 | 148篇 |
1991年 | 146篇 |
1990年 | 136篇 |
1989年 | 139篇 |
1988年 | 137篇 |
1987年 | 109篇 |
1986年 | 152篇 |
1985年 | 256篇 |
1984年 | 263篇 |
1983年 | 184篇 |
1982年 | 229篇 |
1981年 | 205篇 |
1980年 | 212篇 |
1979年 | 187篇 |
1978年 | 138篇 |
1977年 | 145篇 |
1976年 | 135篇 |
1975年 | 99篇 |
1973年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
使用N-甲基吗啉-N-氧化物的水合物(NMMO·H2O)作为再生丝素的溶剂.可以得到w=0.10~0.25的再生丝素/NMMO·H2O溶液.研究了再生丝素/NMMO·H2O溶液流变性能,讨论了剪切速率、温度和溶液中的再生丝素的含量对再生丝素/NMMO·H2O溶液流变性能的影响. 相似文献
62.
Maurizio Massi Giuseppe De Caro Luigi Mazzarella Alan N. Epstein 《Brain research》1986,381(2):289-299
Pigeons with radiofrequency lesions that damaged the subfornical organ (SFO) (n = 4) or that isolated it from adjacent structures (n = 5), but not sham-lesioned pigeons, were unresponsive to blood-borne (i.p.) ANG II (100 micrograms/pigeon) in the immediate postoperative period and for 60 days thereafter. These animals were less sensitive to hypovolemic challenge (20% PEG), but they responded normally to 24 h of water deprivation and to cellular dehydration. Despite their unresponsiveness to bloodborne ANG II, the lesioned pigeons drank normally to 10 ng of i.c.v. ANG II given as early as 10 days after surgery, and they drank reliably and vigorously but less in total volume to 100 ng i.c.v. They also drank quickly, vigorously, and in normal total volume to i.c.v. tachykinins and bombesins, and to the peripheral (i.p.) bombesins. Peripheral (i.m.) tachykinins produced only low volume and variable drinking in all birds tested regardless of brain damage. The SFO of the pigeon, like that of the mammal, is essential for drinking evoked by blood-borne ANG II and is not necessary for thirst aroused by ANG II acting from within the cerebral ventricles. Lastly, it does not mediate the dipsogenic effects of the tachykinins or the bombesins. 相似文献
63.
文章以云南罗平医院为研究对象,调查了65名一般员工和21名科主任级中层领导,使用PM量表对该医院的高层及中层领导行为进行评估,对情景因素与领导行为的内在联系进行探讨,并提出改进对策。目的是了解员工需求,促进人力资源合理配置,从而提高医院的管理水平。 相似文献
64.
党政干部工作倦怠与组织公民行为相关研究 总被引:1,自引:1,他引:0
目的 对党政干部工作倦怠与组织公民行为的相关性进行探讨.方法 采用自编的工作倦怠问卷和组织公民行为问卷对党政干部进行调查,用t检验、方差分析、相关分析、回归分析对数据进行处理.结果 党政干部的工作倦怠和组织公民行为在人口学变量上具有差异,相关分析和回归分析表明,工作倦怠和组织公民行为具有显著负相关.结论 要控制和减少党政干部的工作倦怠,鼓励和增加党政干部的组织公民行为. 相似文献
65.
目的 探讨腹膜后脂肪肉瘤生物学行为及诊断与治疗的有关问题。方法 回顾性分析1970—2005年中国医科大学附属第一医院收治的32例(共接受手术43例次)原发及复发腹膜后脂肪肉瘤病人的临床和病理资料。结果 该病主要临床表现是腹胀、腹部包块进行性增大。复发病例较原发病例生物学行为差,肿瘤侵袭力强,组织学亚型恶性程度高,手术完全切除率低。多次复发者复发间期逐渐缩短。难治性大出血是术后主要且致命的并发症。结论 腹膜后脂肪肉瘤术后易复发,很少转移,手术切除是最有效的治疗手段。完全切除者复发间期长,控制术中出血是减少术后死亡的关键。放、化疗对腹膜后脂肪肉瘤的作用有限。 相似文献
66.
Rapid improvements in the capacity of data processing due to technological breakthroughs in processor engineering is the basis of spatial imaging. Spatial imaging is the main benefit of three-dimensional sonography and it is used for visualization of fetal anatomy in three dimensions. Modern machines are capable of performing spatial imaging in near real time, called four-dimensional sonography. Four-dimensional sonography in multifetal pregnancies can be used for detection and evaluation of intertwin contacts, because it allows simultaneous visualization of both fetuses and assessment of their motor activity. The main benefits of four-dimensional sonography include: accurate recognition of an isolated motor activity of a single fetus; distinguishing between spontaneous and stimulated motor activity; and spatial visualization of the intertwin area. 相似文献
67.
A neurotrophic model for stress-related mood disorders. 总被引:31,自引:0,他引:31
There is a growing body of evidence demonstrating that stress decreases the expression of brain-derived neurotrophic factor (BDNF) in limbic structures that control mood and that antidepressant treatment reverses or blocks the effects of stress. Decreased levels of BDNF, as well as other neurotrophic factors, could contribute to the atrophy of certain limbic structures, including the hippocampus and prefrontal cortex that has been observed in depressed subjects. Conversely, the neurotrophic actions of antidepressants could reverse neuronal atrophy and cell loss and thereby contribute to the therapeutic actions of these treatments. This review provides a critical examination of the neurotrophic hypothesis of depression that has evolved from this work, including analysis of preclinical cellular (adult neurogenesis) and behavioral models of depression and antidepressant actions, as well as clinical neuroimaging and postmortem studies. Although there are some limitations, the results of these studies are consistent with the hypothesis that decreased expression of BDNF and possibly other growth factors contributes to depression and that upregulation of BDNF plays a role in the actions of antidepressant treatment. 相似文献
68.
信息时代高校图书馆信息服务的拓展 总被引:5,自引:0,他引:5
陈艺 《中华医学图书情报杂志》2003,12(3):17-19
论述了信息时代高校图书馆信息服务的优势、模式、特点,探讨了高校图书馆拓展信息服务的策略。 相似文献
69.
董剑桥 《南通大学学报(哲学社会科学版)》2004,20(3):84-88
线性文本与超文本的区别,不只在于文本的结构方式、技术实现方式、阅读写作方式和存储记忆方式等方面,还在于文本的媒体表现方式.狭义的超文本,意指跨越文本局限、打破线性结构的语篇组织方式;广义的超文本,则是指运用超文本标示语言(HTML),经数字化编辑而成的包括文本、音乐、图像、动画、影视等一切表意媒体的信息集合(超文本语篇).因此,超文本连贯性,除了具有线性文本的特征,更有其自身的特点,以视觉原理为基础的数字化修辞手段便是主要手段之一. 相似文献
70.
Background While parenting behaviours have direct effects on children’s behavioural outcomes, other, more distal factors also may be shaping the way a mother handles parenting responsibilities. Dispositional factors are likely to be a major influence in determining how one parents. Although researchers have studied the relationships among maternal dispositional factors, parenting, and child behaviours, few studies have examined these relationships when the child is at developmental risk. Children with developmental delays evidence elevated clinical level behaviour problems, so this group is of primary interest in the search for precursors to psychopathology. The present study examined how the maternal dispositional trait of self‐mastery, as well as supportive and non‐supportive parenting, relate to behaviour problems in young children with and without developmental delay. Method Participants were 225 families, drawn from Central Pennsylvania and Southern California. The children, all aged 4 years, were classified as delayed (n = 97) or non‐delayed (n = 128). The Self‐Mastery Scale measured perceived level of control over life events. The Coping with Children’s Negative Emotions Scale measured different ways parents perceive themselves as reacting to their children’s distress and negative affect. The Child Behavior Checklist assessed children’s behaviour problems. Results Delayed condition mothers reported significantly more child behaviour problems than non‐delayed condition mothers; the two conditions did not differ in self‐mastery, supportive parenting, or non‐supportive parenting. Self‐mastery, non‐ supportive parenting reactions, and child behaviour problems all related significantly to one another. For the sample as a whole and within the delayed condition, the association between self‐mastery and child behaviour problems was partially mediated by non‐supportive parenting reactions, although self‐mastery was still significantly associated with problem behaviour. In the non‐delayed condition, although significant relationships also were found among the variables of interest, non‐supportive parenting did not have a significant main or mediation effect. Delay status moderated the relationship between negative parenting reactions and child behaviour problems, assessed by the Child Behavior Checklist Total and Internalizing scores. When mothers displayed low levels of non‐supportive reactions, children in the delayed and non‐delayed groups had similar levels of total problem behaviour. However, when mothers were medium or high in non‐supportive reactions, children in the delayed group had much higher levels of problem behaviours than those in the non‐delayed group. Conclusions The present study extended research on parental dispositional factors and parenting by measuring self‐mastery as a global personality trait rather than measuring self‐efficacy related specifically to childrearing. Moreover, relationships were examined for both developmentally delayed and non‐delayed samples, allowing for a clearer understanding of the influences on problem behaviours in children with developmental delays. The findings support the view that parenting behaviours have a greater impact on children at developmental risk. 相似文献