全文获取类型
收费全文 | 2272034篇 |
免费 | 174887篇 |
国内免费 | 4091篇 |
专业分类
耳鼻咽喉 | 31811篇 |
儿科学 | 75067篇 |
妇产科学 | 64742篇 |
基础医学 | 322134篇 |
口腔科学 | 65807篇 |
临床医学 | 197678篇 |
内科学 | 445895篇 |
皮肤病学 | 48549篇 |
神经病学 | 183283篇 |
特种医学 | 90994篇 |
外国民族医学 | 767篇 |
外科学 | 348571篇 |
综合类 | 54457篇 |
现状与发展 | 3篇 |
一般理论 | 768篇 |
预防医学 | 173293篇 |
眼科学 | 52603篇 |
药学 | 168855篇 |
3篇 | |
中国医学 | 4290篇 |
肿瘤学 | 121442篇 |
出版年
2018年 | 21574篇 |
2016年 | 18719篇 |
2015年 | 21571篇 |
2014年 | 30054篇 |
2013年 | 46206篇 |
2012年 | 62269篇 |
2011年 | 65792篇 |
2010年 | 39127篇 |
2009年 | 37468篇 |
2008年 | 62989篇 |
2007年 | 66639篇 |
2006年 | 67515篇 |
2005年 | 65746篇 |
2004年 | 64387篇 |
2003年 | 61710篇 |
2002年 | 60599篇 |
2001年 | 104173篇 |
2000年 | 107732篇 |
1999年 | 91569篇 |
1998年 | 25230篇 |
1997年 | 23059篇 |
1996年 | 22867篇 |
1995年 | 22046篇 |
1994年 | 20759篇 |
1993年 | 19681篇 |
1992年 | 74859篇 |
1991年 | 72479篇 |
1990年 | 70856篇 |
1989年 | 68633篇 |
1988年 | 63759篇 |
1987年 | 62878篇 |
1986年 | 60074篇 |
1985年 | 57732篇 |
1984年 | 43350篇 |
1983年 | 37110篇 |
1982年 | 22003篇 |
1981年 | 19517篇 |
1980年 | 18450篇 |
1979年 | 40881篇 |
1978年 | 28540篇 |
1977年 | 24017篇 |
1976年 | 22672篇 |
1975年 | 24303篇 |
1974年 | 29545篇 |
1973年 | 28415篇 |
1972年 | 26286篇 |
1971年 | 24614篇 |
1970年 | 22958篇 |
1969年 | 21522篇 |
1968年 | 20003篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Neurosyphilis today is a rare problem. We describe a man who presented with organic brain syndrome, psychosis and incontinence, and diagnosis was neurosyphilis with resultant bladder dysfunction. Urodynamic studies defined the voiding dysfunction as detrusor areflexia with a positive bethanechol test. This case reminds us of the necessity of obtaining a test for venereal disease to rule out neurosyphilis in patients with idiopathic voiding dysfunction. 相似文献
952.
C L Maini R Antonelli Incalzi M G Bonetti G Valle 《European journal of nuclear medicine》1986,12(2):60-64
A total of 131 patients with old (over 6 months) myocardial infarction (MI) and 18 normal subjects underwent equilibrium radionuclide angiocardiography at rest (rERNA). The following rERNA parameters were assessed: left ventricular ejection fraction (LVEF), peak ejection rate (PER), peak filling rate (PFR), regional wall motion and a left ventricular size index. The patients with old MI were divided into four groups (I to IV) according to increasing left ventricular (LV) size, and the behaviour of the numerical parameters (LVEF, PER, PFR) was evaluated in each group. LVEF proved to be the most sensitive numerical parameter of overall LV performance. PFR decreased significantly from group I to group III but not from group III to group IV, suggesting that for extreme degrees of left ventricular enlargement some compensatory mechanism acts to prevent a too large fall in LV compliance. The effects of the site of the previous MI on LV performance were also evaluated. Both LV size and performance were least affected by postero-inferior MI. The LVEF was, however, a better predictor of LV size than the site of the MI. 相似文献
953.
Two hundred and seventy-seven patients with advanced prostatic cancer were treated by either orchiectomy or oestrogen. During the 2-year follow-up period, the response to treatment was considered more favourable in the oestrogen group, and this response was particularly emphasised in patients with poorly differentiated tumour and metastases at the time of diagnosis. Further evaluations included the cardiovascular side effects of oestrogen therapy. 相似文献
954.
The possible role of nerve activity in triggering changes in the localization of acetylcholine receptors (AChRs) and cholinesterase (ChE) on nerve-contacted Xenopus muscle cells has been assessed. The localization of these molecules was examined on nerve-contacted and noncontacted muscle cells in cultures of spinal cord and myotomal muscle derived from Xenopus embryos. Sites of high AChR density were revealed by staining with fluorescent alpha-bungarotoxin and sites of ChE localization were revealed histochemically. Localization of AChRs and ChE at sites of nerve-muscle contact occurred when the culture medium contained 1.2 micron tetrodotoxin (TTX), 1.2 micron TTX, 10 mM magnesium, and no calcium salts, 1.2 micron TTX and 2 mM manganese, or 106 mM potassium methyl sulfate instead of sodium chloride. The nerve-contacted muscle cells in each of these modified culture media also exhibited a reduced incidence of AChR and ChE patches away from the site of contact. It is concluded that the neural factor(s) that triggers the local and remote changes in AChR and ChE distribution can be supplied to the neurites and externalized in the absence of nerve impulses, and that the nerve and muscle cells can interact even when they are largely depolarized. 相似文献
955.
Localized osteolysis in stable, non-septic total hip replacement 总被引:6,自引:0,他引:6
M J Jasty W E Floyd A L Schiller S R Goldring W H Harris 《The Journal of bone and joint surgery. American volume》1986,68(6):912-919
We are reporting four cases of extensive, localized bone resorption adjacent to a rigidly anchored, cemented total hip replacement. None of these hips showed evidence of infection on clinical, bacteriological, or pathological evaluation. The tissue from the regions of osteolysis showed sheets of macrophages and foreign-body giant cells invading the femoral cortices. Abundant methylmethacrylate particulate debris was present in the tissues, but polyethylene wear debris was absent. The histological appearance of this tissue resembled that reported about loosened total hip implants with the exception of the synovial-like layer at the cement surface. The cases reported here show that aggressive bone lysis may occur around stable cemented total hip arthroplasties without the presence of sepsis or malignant disease. 相似文献
956.
We report 2 cases of diffuse intraperitoneal metastases from testicular carcinoma following transabdominal retroperitoneal lymphadenectomy. This is an unusual pattern of metastasis for nonseminomatous germ cell tumors and it is believed to be the result of direct seeding from lymphatic leakage secondary to surgery. The value of computerized tomography in diagnosing this entity is emphasized. 相似文献
957.
958.
The averaged evoked compound action potentials (AECAPs) were recorded from the ipsilateral pyramidal tract of awake, unrestrained cats before, during, and after continuous electrical stimulation of the cerebral cortex via chronically implanted activated iridium or platinum-30% iridium (Pt30%Ir) microelectrodes. After stimulating 24 h at 20 pulses per second (pps), using charge-balanced, 200-microseconds pulse pairs of 40 to 80 microA (400 to 800 microC/cm2, 8 to 16 nC/phase (ph), 2 to 4 A/cm2), there was a transient elevation of the threshold of the early (direct) and of the alte (transynaptic) components of the AECAP. After cessation of continuous stimulation at 80 microA, the threshold of the early component of the AECAP remained elevated for as long as 24 h and the late component as long as 4 days, indicating significant but reversible depression of the electrical excitability of cortical neurons close to the microelectrodes. In three cats stimulated 23 h/day for 1 week, the AECAP also recovered to their prestimulus threshold. In contrast, pulsing for 24 h at 320 microA (3200 microC/cm2, 64 nC/ph, 16 A/cm2) produced marked elevation of the threshold of the AECAPs which was not reversed by 7 to 12 days after termination of intracortical stimulation. The electrical excitability of neurons adjacent to (unpulsed) microelectrodes 2 mm from the pulsed electrode was not affected. The observations reported here, in conjunction with the histologic results reported in the companion paper, indicate that both the Pt30%Ir and the iridium microelectrodes can be operated safely at currents to at least 80 microA, charge/ph of 16 A/cm2, and a charge density of 800 microC/cm2 X ph. However, on the basis of the electrophysiologic criteria, both types appear to be unsafe when pulsed at 320 microA (64 nC/ph, 3200 microC/cm2 X ph, 16 A/cm2). 相似文献
959.
M F Monge-Strauss F Mikol 《Revue d'électroencéphalographie et de neurophysiologie clinique》1986,16(4):361-369
Non-invasive transcranial Doppler US investigation in adult patients was first described by Aaslid et al. (1982). The apparatus consists in a 2 MHz bidirectional pulsed Doppler with spectrum analyser. Middle and anterior cerebral arteries were insonated by transtemporal exploration, basilar artery by occipital foramen. The criteria of identification were: position and angulation of the probe, direction of the flow, depth of sample volume. The authors present a first series of 31 patients, all with cervical CW Doppler and B-mode Echo. The percentage of identification was: MCA 72%; ACA 69%; BA 54%. Some clinical cases are illustrated. The interest of the method is emphasized in spite of constraints depending on probe position and anatomical variability of the circle of Willis: ambulatory and non-invasive methods; assessment of intracranial blood flow in various conditions: cerebral ischemia and infarction, intracerebral angioma; complementarity with other non-invasive and non-expensive techniques: EEG and cervical US investigation. 相似文献
960.