全文获取类型
收费全文 | 4178996篇 |
免费 | 306867篇 |
国内免费 | 10561篇 |
专业分类
耳鼻咽喉 | 59047篇 |
儿科学 | 133469篇 |
妇产科学 | 113428篇 |
基础医学 | 582564篇 |
口腔科学 | 122885篇 |
临床医学 | 383956篇 |
内科学 | 810229篇 |
皮肤病学 | 93652篇 |
神经病学 | 347371篇 |
特种医学 | 161793篇 |
外国民族医学 | 1454篇 |
外科学 | 622366篇 |
综合类 | 92107篇 |
现状与发展 | 7篇 |
一般理论 | 1798篇 |
预防医学 | 338295篇 |
眼科学 | 96883篇 |
药学 | 307785篇 |
11篇 | |
中国医学 | 8479篇 |
肿瘤学 | 218845篇 |
出版年
2019年 | 33619篇 |
2018年 | 46983篇 |
2017年 | 36039篇 |
2016年 | 40536篇 |
2015年 | 45881篇 |
2014年 | 64565篇 |
2013年 | 96915篇 |
2012年 | 129871篇 |
2011年 | 137919篇 |
2010年 | 81991篇 |
2009年 | 77958篇 |
2008年 | 127833篇 |
2007年 | 135701篇 |
2006年 | 136928篇 |
2005年 | 132563篇 |
2004年 | 127565篇 |
2003年 | 122649篇 |
2002年 | 118272篇 |
2001年 | 188643篇 |
2000年 | 194102篇 |
1999年 | 164726篇 |
1998年 | 49384篇 |
1997年 | 43975篇 |
1996年 | 43584篇 |
1995年 | 42182篇 |
1994年 | 39177篇 |
1993年 | 36729篇 |
1992年 | 130735篇 |
1991年 | 126427篇 |
1990年 | 122189篇 |
1989年 | 118084篇 |
1988年 | 109139篇 |
1987年 | 107545篇 |
1986年 | 101505篇 |
1985年 | 97258篇 |
1984年 | 73215篇 |
1983年 | 62520篇 |
1982年 | 37645篇 |
1981年 | 33871篇 |
1979年 | 67240篇 |
1978年 | 47543篇 |
1977年 | 40302篇 |
1976年 | 37721篇 |
1975年 | 39869篇 |
1974年 | 48286篇 |
1973年 | 46111篇 |
1972年 | 43357篇 |
1971年 | 40184篇 |
1970年 | 37559篇 |
1969年 | 35540篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
R M Abrahams 《British dental journal》1991,170(8):307-308
There is much mystique surrounding the acquisition by a young practitioner of his or her first dental practice, arising largely from his fear of the unknown. In fact, provided that he or she obtains sound legal and commercial advice, he or she can purchase a dental practice almost exclusively out of borrowed capital. Whilst repaying capital (and interest) over a 10-year period, it is possible to earn more from day one than as a relatively experienced associate on the usual commission arrangement. 相似文献
994.
T Misaki S Dokoh T Koh S Shimbo A Hidaka Y Iida K Kasagi J Konishi 《Kaku igaku. The Japanese journal of nuclear medicine》1991,28(2):157-161
In the clinical management of Graves' thyrotoxicosis, one of the most important subject is when to stop antithyroid drugs after achieving an euthyroid state. T3 suppression test and other methods have been used to forecast the outcome after drug cessation, but the results were not always satisfactory. We have attempted to predict remission of Graves' disease by single measurement of early technetium uptake without administration of triiodothyronine. Drugs were discontinued in the seventy-five patients with Graves' disease on maintenance doses of either methimazole or propylthiouracil who showed normalized uptake (4.0% or less). Of 64 patients evaluable after twelve months, 55 (86%) remained euthyroid, 8 relapsed, and 1 became hypothyroid. With its accuracy in prediction of short-term remission comparable or superior to T3 suppression test, this rapid and simple method seemed suitable for routine use in clinical practice. 相似文献
995.
Y Miyasaka M Sakurai A T Yokobori S Kuroda M Ohyama 《Bio-medical materials and engineering》1991,1(1):3-10
Long bone injuries in clinical cases are studied by comparison of roentgenograms with a rational mechanical analysis of the injuries. Fractures produced by torsional loads have a spiral shape with a smooth and even surface. Fractures induced by bending loads have uneven and rugged fracture surfaces perpendicular to the bone axis. Long bones are weak in torsion but strong in tensile stress produced by bending. This result corresponds to the clinical fact that a large direct external force is needed to produce a transverse fracture while a spiral fracture is produced by a relatively small torque. 相似文献
996.
A case of papilliferous keratoameloblastoma is reported which is only the second ever documented. The patient was a 76-yr-old black woman with a large expansile multilocular radiolucency of the body, angle and ramus of the mandible. Histologically the lesion consisted of sheets of cystic follicles filled with necrotic debris and sometimes parakeratin. The vast majority of the follicles were lined by a papilliferous epithelium consisting of large rounded cells with centrally placed nuclei. True papillary projections with cores of connective tissue were also present. The remainder of the follicles were lined by a thin parakeratinising stratified squamous epithelium. Histological features characteristic of ameloblastoma were absent. Final classification of these lesions will have to await the reporting of further cases. 相似文献
997.
998.
Previous studies have shown that stimulation of adrenergic receptors in the brain increases the expression of the immediate early gene (IEG), c-fos, in vivo (Mol. Brain Res., 6(1989) 39-45). The present study was undertaken to determine whether this also holds for other IEGs which have been shown to be activated in brain cell culture by adrenergic agonists. Both yohimbine injection and stressful stimulation, two treatments causing brain norepinephrine (NE) release, were found to cause a parallel, transient activation of at least 5 IEGs (c-fos, nur77, tis-7, zif-268 and tis-21) in the rat cortex. Genes that are not immediate early (beta-actin, NGF and HSP70) were found not to be affected in the interval used (6 h). The responses were mediated predominantly by beta-adrenoceptors with some contribution from alpha 1 receptors. The parallel activation of multiple genes by noradrenergic receptors may enable the coding of different biochemical responses to the activation of different receptors. 相似文献
999.
S C Chua A W Brown J Kim K L Hennessey R L Leibel J Hirsch 《Brain research. Molecular brain research》1991,11(3-4):291-299
We have used a novel method to identify genes expressed in the hypothalamus which may be potentially involved in controlling food intake and energy metabolism. We assumed that food deprivation, a powerful stimulus of food intake, would stimulate the activity of neural pathways involved in feeding behavior which should be reflected in an increase in the synthesis of any relevant neuropeptide and its messenger RNA. A study of 5 neuropeptides in 5 strains of mice has identified neuropeptide Y (NPY) as a gene whose expression in the hypothalamus is controlled by nutritional status, suggesting that hypothalamic NPY neurons are a link in the neural network regulating feeding behavior and energy metabolism. In addition, we have studied the effect of the diabetes mutation on neuropeptide gene expression during fasting and refeeding. Our findings suggest that abnormal NPY and enkephalin gene expression in the hypothalamus may be two important determinants of the expression of the diabetes mutation. 相似文献
1000.
S S Schreiber S Maren G Tocco T J Shors R F Thompson 《Brain research. Molecular brain research》1991,11(1):89-91
In the present study we examined the relationship between the induction of long-term potentiation (LTP) in the dentate gyrus of anesthetized rats and activation of immediate early genes (IEGs; c-fos and zif/268) using several different high-frequency stimulation paradigms. Stimulation parameters that effectively induced LTP were not associated with IEG activation. Conversely, stimulation parameters that failed to induce LTP consistently resulted in IEG activation. These results suggest that there is a negative correlation between IEG activation and LTP, and that activation of IEGs is neither necessary nor sufficient for the induction of LTP. 相似文献