全文获取类型
收费全文 | 2119篇 |
免费 | 105篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 156篇 |
妇产科学 | 21篇 |
基础医学 | 191篇 |
口腔科学 | 47篇 |
临床医学 | 194篇 |
内科学 | 609篇 |
皮肤病学 | 24篇 |
神经病学 | 66篇 |
特种医学 | 481篇 |
外科学 | 174篇 |
综合类 | 29篇 |
预防医学 | 93篇 |
眼科学 | 16篇 |
药学 | 68篇 |
中国医学 | 3篇 |
肿瘤学 | 73篇 |
出版年
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 32篇 |
2014年 | 37篇 |
2013年 | 68篇 |
2012年 | 38篇 |
2011年 | 50篇 |
2010年 | 95篇 |
2009年 | 76篇 |
2008年 | 81篇 |
2007年 | 55篇 |
2006年 | 61篇 |
2005年 | 44篇 |
2004年 | 35篇 |
2003年 | 46篇 |
2002年 | 37篇 |
2001年 | 38篇 |
2000年 | 40篇 |
1999年 | 43篇 |
1998年 | 134篇 |
1997年 | 126篇 |
1996年 | 127篇 |
1995年 | 95篇 |
1994年 | 79篇 |
1993年 | 84篇 |
1992年 | 27篇 |
1991年 | 37篇 |
1990年 | 25篇 |
1989年 | 68篇 |
1988年 | 54篇 |
1987年 | 60篇 |
1986年 | 51篇 |
1985年 | 50篇 |
1984年 | 28篇 |
1983年 | 32篇 |
1982年 | 35篇 |
1981年 | 23篇 |
1980年 | 37篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1977年 | 19篇 |
1976年 | 24篇 |
1975年 | 25篇 |
1966年 | 2篇 |
1938年 | 2篇 |
排序方式: 共有2246条查询结果,搜索用时 125 毫秒
171.
172.
173.
Our aim was to determine if chronic blockade of GABAergic inhibitory synaptic activity, monitored electrophysiologically at the neuronal level, would affect synapse formation and ultrastructure in dissociated fetal rat cerebral cortex cultures. This was achieved by adding picrotoxin to the serum-free growth medium in a dose that induced continuous epileptiform discharges throughout the culture period. Light and electron microscopic analysis suggested an accelerated synaptic network formation in the experimental cultures during the first 2 weeks in vitro. The elimination of excess synapses (mainly on spines), which normally takes place during the fourth week in vitro, occurred 1 week earlier in the presence of picrotoxin. Finally, the experimental cultures showed smaller spine synapses throughout the entire culture period. Because these effects were opposite those induced by chronic tetrodotoxin-blockade of spontaneous bioelectric activity in a previous study, the underlying causal factor could be the respective intensification and suppression of neuronal activity in the two experiments. An appropriate balance between excitatory and inhibitory synaptic drive seems therefore to be important for normal maturation of neocortical circuitry. 相似文献
174.
The first case of Dupuytren's contracture in a black patient with no obvious caucasian admixture was reported in 1979. This condition is rare in the purely black population and since 1979 only 23 cases have been reported. We present the case of a black man with no history of caucasian admixture with bilateral Dupuytren's contracture. We suggest that this condition may not be as rare as the literature suggests and, that canvassing other hand societies for their experience, particularly in the continent of Africa, may help to establish the true incidence of this condition. 相似文献
175.
Mueller PR; Silverman SG; Tung G; Brink JA; Cardenosa G; Saini S; Forman BH; Hahn PF 《Radiology》1989,173(1):278-279
A new tray has been designed for use during procedures involving needles and other sharp objects. The tray includes a foam adhesive pad, marked into 10 sections, into which the sharp objects can be placed point first. After the procedure, the objects can be safely withdrawn by their handles and then discarded. The tray has been used in more than 250 procedures. 相似文献
176.
Jaundice develops in many patients with liver metastases from colorectal adenocarcinoma during hepatic arterial infusion chemotherapy (HAIC). The usual cause is thought to be hepatotoxicity from the chemotherapeutic agent or biliary obstruction from progressive neoplastic disease. The authors evaluated the abdominal computed tomography and ultrasound examinations performed on 49 patients who were jaundiced during long-term HAIC. In only one patient was diffuse intrahepatic biliary dilatation caused by an obstructing mass in the porta. Two patients had metastatic hepatic lesions causing focal biliary obstruction. Intrahepatic dilatation without an obstructing mass occurred in 20 patients. Percutaneous or endoscopic cholangiograms were commonly interpreted prospectively as showing extrinsic compression by metastases, but no mass was confirmed on imaging studies. Seven patients had focal intrahepatic ductal dilatation from stricture without an associated mass. The remaining 19 patients had normal-caliber ducts; their jaundice was caused by chemical hepatitis. This series suggests that the most common causes of jaundice in these patients are chemical hepatitis and common bile duct stricture, complications of intraarterial chemotherapy, rather than neoplastic obstruction. Stricture formation may be confused with extrinsic compression on direct cholangiograms. 相似文献
177.
178.
Childhood scoliosis: MR imaging 总被引:2,自引:0,他引:2
Nokes SR; Murtagh FR; Jones JD d; Downing M; Arrington JA; Turetsky D; Silbiger ML 《Radiology》1987,164(3):791-797
The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n = 5), Arnold-Chiari I malformation (n = 4), spinal cord tumors (n = 2), Arnold-Chiari II malformation (n = 3), and diastematomyelia (n = 1). The advantages of MR imaging in the evaluation of the scoliotic spine in children include a high sensitivity for the occult conditions associated with scoliosis, good anatomic demonstration of the cord, and absence of bone artifacts. MR imaging is recommended as a primary imaging modality in scoliosis, following conventional radiography. 相似文献
179.
Di Chiro G; Girton ME; Frank JA; Dietz MJ; Gansow OA; Wright DC; Dwyer AJ 《Radiology》1986,160(1):221-222
Canine cerebrospinal fluid rhinorrhea, which occurs frequently in purebred beagles, was demonstrated in two dogs on magnetic resonance images after cisternal introduction of gadolinium-DTPA dimeglumine. 相似文献
180.
The ability of diagnostic intravenous digital subtraction angiography (IVDSA) to demonstrate the degree of renal artery stenosis was compared with that of intraarterial angiography in 45 patients with 92 arteries. Stenotic lesions on both IVDSA and intraarterial studies were classified as normal (0% stenosis), minor (less than 50%), low grade (50%-80%), and high grade (80%-99%). There was agreement about the degree of stenosis in 90% of the cases. IVDSA grading was correct in 94% of atheromatous lesions and in 56% of the fibromuscular dysplastic lesions. In the high-grade atheromatous lesions, the degree of stenosis was slightly overestimated on IVDSA studies in 22.5% of the cases. In fibromuscular dysplasia, stenosis was underestimated in 33% of the cases. 相似文献