全文获取类型
收费全文 | 24530篇 |
免费 | 2255篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 208篇 |
儿科学 | 632篇 |
妇产科学 | 591篇 |
基础医学 | 3373篇 |
口腔科学 | 649篇 |
临床医学 | 2584篇 |
内科学 | 5068篇 |
皮肤病学 | 311篇 |
神经病学 | 2537篇 |
特种医学 | 1165篇 |
外国民族医学 | 1篇 |
外科学 | 3112篇 |
综合类 | 668篇 |
一般理论 | 25篇 |
预防医学 | 2181篇 |
眼科学 | 646篇 |
药学 | 1720篇 |
2篇 | |
中国医学 | 38篇 |
肿瘤学 | 1317篇 |
出版年
2021年 | 269篇 |
2020年 | 182篇 |
2019年 | 287篇 |
2018年 | 377篇 |
2017年 | 297篇 |
2016年 | 290篇 |
2015年 | 347篇 |
2014年 | 492篇 |
2013年 | 885篇 |
2012年 | 1133篇 |
2011年 | 1232篇 |
2010年 | 650篇 |
2009年 | 642篇 |
2008年 | 1128篇 |
2007年 | 1200篇 |
2006年 | 1246篇 |
2005年 | 1272篇 |
2004年 | 1237篇 |
2003年 | 1156篇 |
2002年 | 1177篇 |
2001年 | 536篇 |
2000年 | 509篇 |
1999年 | 484篇 |
1998年 | 321篇 |
1997年 | 270篇 |
1996年 | 268篇 |
1995年 | 288篇 |
1994年 | 258篇 |
1993年 | 235篇 |
1992年 | 407篇 |
1991年 | 467篇 |
1990年 | 430篇 |
1989年 | 360篇 |
1988年 | 416篇 |
1987年 | 358篇 |
1986年 | 348篇 |
1985年 | 373篇 |
1984年 | 333篇 |
1983年 | 261篇 |
1982年 | 226篇 |
1981年 | 237篇 |
1980年 | 216篇 |
1979年 | 279篇 |
1978年 | 226篇 |
1977年 | 223篇 |
1976年 | 206篇 |
1975年 | 203篇 |
1974年 | 218篇 |
1973年 | 170篇 |
1972年 | 186篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Very little information is available concerning the pharmacology of type 2 astroglia. During the past decade it has become apparent that two distinct lineages of astroglial cells can be defined in vitro. These two lineages are commonly referred to as type 1 and type 2 and are distinguished from each other on the basis of their morphological features and antigenic phenotypes. In contrast to type 1 astroglia, very little is known about the pharmacology of type 2 astroglia. The lack of information concerning the responsiveness of these cells stems primarily from difficulties encountered in isolating large numbers of type 2 astroglia free of other cell types. In the present study video- and photometer-based imaging systems were used to monitor the influence of a series of neuroligands on the intracellular calcium levels of individual cerebral type 2 astroglia in order to assess their expression of calcium-mobilizing receptors. The responses of 85 immunocytochemically identified cerebral type 2 astroglia to bradykinin (BK), norepinephrine (NE), histamine (HIST), carbachol (CARB), 2-methyl-thio ATP (2MT-ATP), glutamate (GLUT), and serotonin (5-HT) were analyzed. Approximately 50% of cerebral type 2 astroglia responded to BK, NE, HIST, CARB, and 2MT-ATP whereas only 16% and 9% of the cells responded to GLUT and 5-HT, respectively. The number of neuroligands that increased calcium in individual cells ranged from 0 to 6. These responses are quite similar to those previously demonstrated in cultured cerebral type 1 astroglia. No pattern of receptor co-expression was observed for the different neuroligands tests.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
22.
23.
Pitfalls in diagnosis of aortic dissection by angiography: Algorithmic approach utilizing CT and MRI
Harold L. Mast David H. Gordon Alan M. Kantor 《Computerized medical imaging and graphics》1991,15(6):431-440
Dissection of the thoracic aorta is a life-threatening event requiring imaging studies to define the level of the tear and the intinmal flap. The “gold standard” has been angiography. This method may fail to demonstrate the dissection, however, due to overlap of the true and false lumens or a very thin flap that is imaged en face rather than tangentially. Computed tomography has a diagnostic accuracy of 95%, but can fail to image the dissection due to technical factors or a thrombosed false hunen. Magnetic resonance imaging requires a hemodynamically stable and cooperative patient. A diagnostic algorithm is proposed for diagnosis of aortic dissection based on renal function and the surgeon's imaging modality preference. 相似文献
24.
This case study describes the use of a behavioral intervention to treat bisexual aggression of an adult with developmental disabilities. Treatment involved the suppression of deviant sexual behavior and enhancement of appropriate social interactions. Implementation of the intervention resulted in an immediate reduction in sexual aggression. Long-term follow-up indicated no further occurrences of the behavior.Discussion focuses on the limited data regarding the assessment and treatment of persons who are developmentally disabled and engage in deviant sexual behavior, determination of consenting sexual relations, and development of behavioral interventions.The comments of Lew Lewin are appreciated. Reprints can be obtained by contacting Duane Lundervold at LINC Behavioral Services, 1430 Willamette, Suite 363, Eugene, Oregon 97401. 相似文献
25.
B Marcus K Sivazlian L S Gordon 《Journal of the American Society of Echocardiography》1991,4(4):405-407
We report the two-dimensional and Doppler color flow mapping echocardiographic findings in a neonate with left circumflex coronary arteriovenous fistula to a left superior vena cava. Doppler color flow mapping, in concert with detailed imaging, was essential to identify this rare fistula and to prepare for therapeutic intervention at initial cardiac catheterization. 相似文献
26.
Shelley A. Klemm Richard D. Gordon Terry J. Tunny Wendy L. Finn 《Clinical and experimental pharmacology & physiology》1990,17(3):191-195
1. Plasma potassium and chloride concentrations were raised and plasma renin activity, aldosterone, bicarbonate and arterial pH were reduced in two brothers with the syndrome of hypertension and hyperkalaemia with normal glomerular filtration rate (Gordon's syndrome), on unrestricted or moderately restricted sodium diets. 2. These abnormalities were corrected in both patients within 10 days of severe sodium restriction. 3. Pressor sensitivity to cold and angiotensin II decreased on low sodium diet, associated with a fall in blood pressure. 4. Increasing distal tubular sodium delivery by infusion of normal saline increased fractional excretion of potassium when aldosterone had been stimulated by severely restricted sodium diet, but not when aldosterone levels were low on unrestricted sodium diet. 5. These findings are consistent with excessive sodium reabsorption as the primary renal lesion in Gordon's syndrome, leading to volume expansion and suppression of renin and aldosterone. Severe dietary sodium restriction leading to volume contraction, by stimulating renin and aldosterone and promoting kaliuresis, corrects the abnormalities. 相似文献
27.
Pyomyositis: characteristics at CT and MR imaging 总被引:9,自引:0,他引:9
28.
Patrick E. Barta Richard E. Powers Elizabeth H. Aylward Gary A. Chase Gordon J. Harris Peter V. Rabins Larry E. Tune Godfrey D. Pearlson 《Psychiatry Research: Neuroimaging》1997,68(2-3):65-75
Volumes of medial and lateral temporal lobe structures were assessed using magnetic resonance imaging (MRI) in 11 patients with late-life onset schizophrenia (LOS), 18 normal elderly controls and 12 patients with moderate cognitive impairment due to Alzheimer's disease (AD) who had no non-cognitive symptoms. While both patient groups has smaller volumes of several medial temporal regions (e.g. entorhinal cortex, left hippocampus), schizophrenics had significantly smaller anterior superior temporal gyri (STG) than normal controls, but AD patients did not. We have previously demonstrated anterior STG volume to be reduced in early life onset schizophrenia. 相似文献
29.
30.
Although a great deal is known about the nature and severity of the recent financial crisis in agriculture, there has been little systematic study of the social and psychological effects of this crisis upon farm operators and their families. Using data from a statewide sample of Iowa farmers, this study tests some hypotheses about correlates of psychological stress. The findings suggest that many farm operators find their situations to be stressful and that such stress is related to the severity of their financial problems. In addition, the life-events perspective is examined in its utility to explain how adverse economic changes impact psychological well-being. 相似文献