全文获取类型
收费全文 | 733438篇 |
免费 | 36375篇 |
国内免费 | 1036篇 |
专业分类
耳鼻咽喉 | 9383篇 |
儿科学 | 22989篇 |
妇产科学 | 17668篇 |
基础医学 | 121412篇 |
口腔科学 | 19199篇 |
临床医学 | 61542篇 |
内科学 | 140383篇 |
皮肤病学 | 18127篇 |
神经病学 | 50958篇 |
特种医学 | 24647篇 |
外国民族医学 | 83篇 |
外科学 | 102428篇 |
综合类 | 8633篇 |
现状与发展 | 2篇 |
一般理论 | 141篇 |
预防医学 | 61008篇 |
眼科学 | 16703篇 |
药学 | 56480篇 |
1篇 | |
中国医学 | 1888篇 |
肿瘤学 | 37174篇 |
出版年
2021年 | 7926篇 |
2019年 | 7956篇 |
2018年 | 11543篇 |
2017年 | 7842篇 |
2016年 | 8691篇 |
2015年 | 9564篇 |
2014年 | 12483篇 |
2013年 | 18320篇 |
2012年 | 27881篇 |
2011年 | 30234篇 |
2010年 | 16809篇 |
2009年 | 14474篇 |
2008年 | 26260篇 |
2007年 | 28541篇 |
2006年 | 27701篇 |
2005年 | 26763篇 |
2004年 | 25504篇 |
2003年 | 24267篇 |
2002年 | 23436篇 |
2001年 | 28332篇 |
2000年 | 29236篇 |
1999年 | 23990篇 |
1998年 | 6567篇 |
1997年 | 5315篇 |
1996年 | 5297篇 |
1995年 | 4923篇 |
1992年 | 17086篇 |
1991年 | 18357篇 |
1990年 | 18384篇 |
1989年 | 17711篇 |
1988年 | 16281篇 |
1987年 | 16007篇 |
1986年 | 15014篇 |
1985年 | 14421篇 |
1984年 | 10669篇 |
1983年 | 9108篇 |
1979年 | 10282篇 |
1978年 | 7266篇 |
1977年 | 6009篇 |
1976年 | 6298篇 |
1975年 | 7571篇 |
1974年 | 8639篇 |
1973年 | 8391篇 |
1972年 | 7751篇 |
1971年 | 7412篇 |
1970年 | 6939篇 |
1969年 | 6556篇 |
1968年 | 6258篇 |
1967年 | 5610篇 |
1966年 | 4887篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
101.
The effect of proteases inhibitors, epsilon-amino-caproic acid and gordox, on reproduction of rotavirus SA-11 in MA-104 cells was studied by enzyme immunoassay. These inhibitors were shown to exert an inhibiting effect on rotavirus reproduction. 相似文献
102.
Trends in analgesic self-poisoning in West-Fife, 1971-1985 总被引:1,自引:0,他引:1
J J McMurray D B Northridge V A Abernethy A A Lawson 《The Quarterly journal of medicine》1987,65(246):835-843
All admissions for analgesic self-poisoning to a district poisons unit over a 15-year period have been reviewed. During this time overdose with analgesic drugs increased to represent almost half of all admissions for self-poisoning. The types of analgesics taken in overdose also changed significantly during the period of this review. Aspirin and Distalgesic poisoning declined in incidence and more cases of self-poisoning by paracetamol and non-steroidal anti-inflammatory agents were seen. The impact of these changes on the medical management and outcome of deliberate self-poisoning is analysed. The reasons behind the trends described in this paper are assessed and their implications for future prevention and treatment are discussed. 相似文献
103.
104.
Familial expansile osteolysis: a morphological, histomorphometric and serological study. 总被引:1,自引:0,他引:1
Biopsies from the diseased bones of patients with familial expansile osteolysis (FEO) were examined by light and electron microscopy. Focal concentrations of multinuclear osteoclasts were present, and these contained viral-like microcylindrical inclusions which appeared exclusive to their nuclei. No consistent relationship was found between osteoclast size and the number of osteoclast nuclei containing microcylindrical inclusions. Quantitative histomorphometry showed evidence of increased bone remodelling with high bone cell densities and a decrease of the reversal period in bone remodelling. The lesions contained prominent woven bone and fibrovascular tissue, together with mononuclear cells and adipocytes. Little bone was found in the most radiolucent lesions, which were almost totally occupied by adipocytes and fibrovascular tissue. Serology did not reveal any significant differences between the viral antibody titres of patients and their age- and sex-matched controls. The present study suggests that intranuclear viral-like microcylindrical inclusions of osteoclasts are not a specific feature of Paget's disease, and are found in other disorders of osteoclast function, including pycnodysostosis, osteopetrosis, giant cell tumours, and familial expansile osteolysis. 相似文献
105.
M. L. Hernández J. J. Fernández-Ruiz R. de Miguel J. A. Ramos 《Journal of neural transmission (Vienna, Austria : 1996)》1991,83(1-2):77-84
Summary In this work, we have studied the time-course of the effects of pharmacological administration of ovarian steroids on tyrosine hydroxylase (TH) activity in the limbic forebrain of ovariectomized rats. Administration of estradiol produced a late decrease in TH activity. This effect was found 24 hours after the last steroid injection, disappearing at 32 hours. It was antagonized by progesterone, since a single injection of this steroid to estradiol-pretreated rats reversed to control values the estradiol-induced decrease. Nevertheless, the administration of progesterone after estradiol treatment caused a short-time decrease in the limbic activity of TH, which was observed 4 hours after the last steroid injection, disappearing subsequently. On the other hand, the administration of progesterone alone produced a biphasic effect, with a reduction at 24 hours, followed by an increase at 32 hours. These effects were only observed in the animals non-treated with estradiol, disappearing with a previous treatment with estrogens. Hence, it can be concluded that both ovarian steroids may affect the limbic TH activity. Thus, estradiol produced a late inhibitory effect on the activity of this enzyme, which was antagonized by progesterone. Administration of the last one to estradiol-treated rats produced a short-time inhibitory effect, whereas its administration to non-treated rats produced a late biphasic effect (inhibition followed by stimulation), which was not observed in estradiol-treated rats. 相似文献
106.
Expression of the neurofilament protein NF-H in L cells. 总被引:1,自引:0,他引:1
107.
Melatonin, a pineal hormone, released photoperiodically, was administered systemically in rats, previously implanted with semimicroelectrodes into six different brain structures. The multiunit electrical activity of these structures was recorded for 10 min before and 60 min after melatonin administration in unanesthetized, freely moving rats. Different melatonin doses (100, 200, 500, and 1000 micrograms/kg) produced changes in the electrical activity of all tested structures. However, amygdala, rostral hypothalamus and mesencephalic reticular formation showed the most important changes. The main effect induced by melatonin was a dose-related decrease of the spontaneous electrical activity. The significance of these effects is discussed within the context of the behavioral and endocrinological effects of melatonin. 相似文献
108.
The connective tissue of the knee is frequently injured by athletes, especially those involved in contact sports. It would be important in the prevention of injury as well as the strategy of physical fitness training to know whether the connective tissue is modified in response to athletic stress or training. The potential modification investigated was variability in the concentration of hydroxyproline, a post-translationally modified imino acid found principally in collagen protein. A correlation was sought between this variability and the leg strength parameters torque (expressed as ft-lbs), torque/body weight and work (expressed as ft-lbs). In a preliminary study of five subjects, no correlation was found between hydroxyproline concentration of the patellar tendon and any of the leg strength parameters. These results suggest that this modification of the collagen in connective tissue does not occur in response to athletic stress or training, but rather, for the small number of subjects investigated, appeared to be relatively constant across a range of leg strengths. 相似文献
109.
This study was undertaken to assess the role of the hypothalamus and medulla oblongata in regulation of liver circulation in anesthetized dogs. Blood pressure, flow in hepatic artery and portal vein, and shifts of blood volume in the liver were recorded. Stimulation of the anterior hypothalamus produced changes in arterial pressure which were followed by passive changes in hepatic arterial blood flow; changes in hepatic artery resistance were rather small. Stimulation of the medial and posterior hypothalamus increased hepatic arterial resistance by 65-170%. Liver portal blood flow during stimulation of most of the hypothalamic sites decreased, hepatic portal pressure rose and vascular portal venous resistance increased 2.5-3 times. Three areas only (sympatho-inhibitory area, paraventricular and lateral hypothalamic nuclei) when stimulated produced dilatation of hepatic portal and splanchnic vascular beds, thus increasing portal blood flow. All cases of stimulation led to the decrease of blood volume in the liver by 10-36%. Stimulation of medullary structures (n. tractus solitarii, reticular nn.) caused similar changes in hepatic circulation, however the amplitude of reaction was 1.5-6 times smaller than upon hypothalamic stimulation. Central impulses to the hepatic vessels are transmitted by sympathetic adrenergic nerve fibers through vascular alpha-adrenoreceptors. It is concluded that the hypothalamic level of the central nervous system, unlike the bulbar one, exerts considerable, differentiated, well coordinated and to some extent specific influences on hepatic circulation. 相似文献
110.
V DeBack 《Nursing outlook》1991,39(3):124-127
On May 1, 1991, the National Commission on Nursing Implementation Project officially concluded. Its legacy is one of interdisciplinary collaboration and continuing work to redesign nursing education, practice, and research systems. 相似文献