全文获取类型
收费全文 | 422768篇 |
免费 | 28867篇 |
国内免费 | 2863篇 |
专业分类
耳鼻咽喉 | 5801篇 |
儿科学 | 9427篇 |
妇产科学 | 11303篇 |
基础医学 | 59849篇 |
口腔科学 | 12811篇 |
临床医学 | 36049篇 |
内科学 | 86285篇 |
皮肤病学 | 9127篇 |
神经病学 | 30722篇 |
特种医学 | 15339篇 |
外国民族医学 | 83篇 |
外科学 | 66429篇 |
综合类 | 10847篇 |
现状与发展 | 1篇 |
一般理论 | 93篇 |
预防医学 | 22010篇 |
眼科学 | 10093篇 |
药学 | 34511篇 |
1篇 | |
中国医学 | 2252篇 |
肿瘤学 | 31465篇 |
出版年
2021年 | 3201篇 |
2019年 | 3397篇 |
2018年 | 5296篇 |
2017年 | 3989篇 |
2016年 | 4216篇 |
2015年 | 4749篇 |
2014年 | 6693篇 |
2013年 | 8891篇 |
2012年 | 12050篇 |
2011年 | 12275篇 |
2010年 | 7363篇 |
2009年 | 6886篇 |
2008年 | 11273篇 |
2007年 | 12188篇 |
2006年 | 12047篇 |
2005年 | 11091篇 |
2004年 | 10516篇 |
2003年 | 10206篇 |
2002年 | 9923篇 |
2001年 | 29723篇 |
2000年 | 30293篇 |
1999年 | 24953篇 |
1998年 | 5748篇 |
1997年 | 4745篇 |
1996年 | 4244篇 |
1995年 | 3934篇 |
1994年 | 3530篇 |
1993年 | 3230篇 |
1992年 | 17113篇 |
1991年 | 15824篇 |
1990年 | 15156篇 |
1989年 | 14880篇 |
1988年 | 13435篇 |
1987年 | 12924篇 |
1986年 | 11945篇 |
1985年 | 11187篇 |
1984年 | 7607篇 |
1983年 | 6193篇 |
1982年 | 3143篇 |
1979年 | 6045篇 |
1978年 | 3786篇 |
1977年 | 3325篇 |
1976年 | 2604篇 |
1975年 | 2921篇 |
1974年 | 3437篇 |
1973年 | 3196篇 |
1972年 | 3161篇 |
1971年 | 3073篇 |
1970年 | 2765篇 |
1969年 | 2807篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
921.
922.
T. Terada H. Matsumoto Y. Nakamura Y. Kinoshita E. Nakai K. Nakai T. Itakura 《Neuroradiology》1996,38(7):615-617
A transjugular snare technique was used to retrieve a stretched, residual mechanical detachable coil which extended from
the cavernous sinus to the femoral vein, obliterating the transpetrosal route for further embolisation. The coil was snared
by a microguidewire. Our new technique is described in this paper.
Received: 19 April 1995 Accepted: 31 July 1995 相似文献
923.
924.
We describe a simple, quick ultrasound screening test for CDH, and its use in a prospective study of babies with a 'high risk' factor, over one year from January 1987. From a birth population of 3,879, 812 hip scans were performed on 406 babies and 98 babies were abnormal. So far, there have been no late cases of CDH. Family history, breech malposition, and postural foot deformities were confirmed to be important risk factors, but babies with a simple click were equally at risk. Our early results indicate that a large proportion of the potential late cases are contained within our extended high-risk group. 相似文献
925.
T Tokunaga M Shigemori M Katayama S Kuramoto H Hayashi K Yamada K Nonaka Y Sasaguri 《No shinkei geka. Neurological surgery》1990,18(2):183-188
Lymphocytic adenohypophysitis is considered to be an inflammatory disease of the adenohypophysis that is commonly present with visual disturbance and hypopituitarism. Its etiology remains unclear but it is often related to an autoimmune disorder involving other organs, such as the thyroid, parathyroid, or adrenal glands. We encountered a rare case of lymphocytic adenohypophysitis associated with sarcoidosis of the lung and eye during the follow-up period. A 23-year-old woman was hospitalized in July 1986, with a one-month history of headache and visual disturbances which began three days after her second normal delivery. On admission, she showed slight visual impairment and had a left temporal superior quadrantanopia. Endocrinological evaluation revealed thyroid and adrenal hypofunction, and low response of human growth hormone to the loading test. A skull X-ray showed normal shaped sella with some erosion of the dorsum. CT scan showed a rounded contrast-enhanced intrasellar mass extending into the suprasellar cistern. MRI (SR: 500/30) showed a homogeneous low intensity mass which contained a small high intensity area on the relative T2-weighted image (2000/50). A biopsy was performed via right frontotemporal craniotomy. The consistency of the resected tissue was firmer than that of pituitary adenoma. Histologically, the tissue showed diffuse lymphocytic infiltration with some normal adenohypophysis. Her postoperative course was uneventful and the visual impairment improved two months later after the operation. Six months after the operation, she was readmitted with complaints of general fatigue and breathlessness. Chest X-ray showed diffuse infiltration throughout both lung fields, but there was no bilateral hilar lymphadenopathy.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
926.
Y Masuyama Y Kodama Y Matsuura A Sawada K Harada T Tsuchiya 《Journal of clinical neuro-ophthalmology》1990,10(1):1-8
We reviewed retrospectively 20 cases of optociliary vein over the past 5 years. Fifteen of the 20 cases (75%) were over 40 years of age. There was no sex differences (9 males and 11 females). Causative ocular diseases were: central retinal vein occlusion (14 cases, 70%); optic disc drusen (2 cases, 10%); and optic nerve sheath meningioma, high myopia, glaucoma, congenital anomaly (1 case each, total 20%). The number of patients with an optociliary vein was high in central retinal vein occlusion (14/190 cases, 7.4%). We concluded that occurrence of optociliary vein is not restricted to cases with optic nerve sheath meningioma and this shunt vessel may occur under other conditions in which central retinal venous return is seriously disturbed. The most common cause of optociliary vein is central retinal vein occlusion. 相似文献
927.
The main PERG component of the transient contrast reversal pattern electroretinogram (PERG) in cats was a negative wave (3.5 microV average, SD 1.7 microV) peaking at about 130 msec (N130) with a spatial resolution above 5.5 c/deg, close to behavioural estimates. The early positivity (P35) was more variable, smaller and had lower spatial resolution. Different anaesthetic protocols affected both the waveform and the amplitude by spatial frequency functions. Responses of urethane anaesthetised cats were like those reported previously for decerebrate cats or cats paralysed and ventilated with N2O/O2/CO2 (75%/24%/1%). P35 was evoked only by coarse stimuli and N130 amplitude decreased linearly as spatial frequency increased. When the luminance response amplitude, predicted from the optical transfer function of the eye, was subtracted, spatial tuning appeared. An anaesthetic mixture of ketamine hydrochloride and xylazine depressed both P35 and N130 at low spatial frequencies while enhancing them at high frequencies. In paralysed animals ventilated with N2O/O2 (67%/33%) P35 was larger and recordable to 1.6 c/deg. Peak times were reduced and the inter-peak time halved. Other anaesthetics depressed the ERGs. These effects suggest that cats are a good model for studying N130 in isolation or its interaction with P35 and that both PERG peaks include luminance and pattern components. 相似文献
928.
This study evaluated the changes in renal function that occur during the early phases of chronic infusion of carbachol into the lateral ventricle in conscious rats. Infusion of 1.0 micrograms/h of carbachol i.c.v. resulted in a prompt pressor response with mean arterial pressure rising 20 mm Hg within 15 min. The pressure remained elevated for the duration of a 2-hour infusion. Carbachol infusion at 0.5 micrograms/h induced a similar elevation in blood pressure, but the onset was delayed, reaching significance only after 30-60 min. The higher dose of carbachol was associated with a marked and sustained natriuresis, with sodium excretion increasing from 2.1 +/- 0.3 to 5.3 +/- 1.0 microEq/100 g min after 2 h, compared to 2.0 +/- 0.5 and 1.8 +/- 0.3 microEq/100 g min in vehicle-infused control animals. Sodium excretion did not change significantly in animals infused with carbachol at 0.5 microgram/h. There were no significant changes in glomerular filtration rate in any of the groups. Plasma levels of atrial natriuretic peptide (ANP) were not altered significantly by ventricular infusion of carbachol (188 +/- 99 before vs. 83 +/- 17 pg/ml after infusion). It is concluded that the pressor response to central carbachol infusion is not dependent on retention of sodium and water. The natriuresis observed with carbachol infusion can be dissociated from the pressor response, and is not mediated by ANP. 相似文献
929.
The study was performed to clarify the relationship between the long-term prognosis of IgA nephropathy and the HLA-DR4 antigen. From the 130 patients typed for HLA antigens, stable (n = 42) and progressive (n = 45) patient groups were selected. DR4 frequency was not different in the two groups (stable, 66.7 vs. progressive, 53.3%). However, the frequencies of HLA-DR4 and B35 in the 130 patients were significantly higher than those in the national control (DR4; 60.0 vs. 41.6%; B35:30.0 vs. 15.5%). We concluded that DR4 played no role in the long-term prognosis of IgA nephropathy, but that B35 and DR4 were associated with the disease in the Japanese population. 相似文献
930.
Magnetic resonance imaging of 31 meningiomas in 29 patients was retrospectively reviewed and compared with pathologic specimens in 25 tumors to investigate how magnetic resonance imaging could delineate a tumor-brain interface. The thick, collagenous connective tissue, which was seen around four tumors, was shown as a low signal intensity rim on both a T1-weighted image and a T2-weighted image. A rim of low signal intensity on a T1-weighted image and high signal intensity on a T2-weighted image most likely represented cerebrospinal fluid space: this finding was seen around eight tumors. No distinct rim could be identified in five tumors. Of these five, two tumors grew invasively into the brain. Although mixed features predominated in meningiomas, magnetic resonance imaging could well delineate a tumor-brain relationship in most of the cases. 相似文献