全文获取类型
收费全文 | 530191篇 |
免费 | 27653篇 |
国内免费 | 497篇 |
专业分类
耳鼻咽喉 | 6681篇 |
儿科学 | 16927篇 |
妇产科学 | 12549篇 |
基础医学 | 92633篇 |
口腔科学 | 12355篇 |
临床医学 | 48511篇 |
内科学 | 95456篇 |
皮肤病学 | 11869篇 |
神经病学 | 34022篇 |
特种医学 | 19763篇 |
外国民族医学 | 53篇 |
外科学 | 78078篇 |
综合类 | 7612篇 |
现状与发展 | 2篇 |
一般理论 | 107篇 |
预防医学 | 38539篇 |
眼科学 | 11943篇 |
药学 | 41452篇 |
1篇 | |
中国医学 | 1127篇 |
肿瘤学 | 28661篇 |
出版年
2021年 | 3900篇 |
2018年 | 5742篇 |
2017年 | 4132篇 |
2016年 | 4877篇 |
2015年 | 5364篇 |
2014年 | 7123篇 |
2013年 | 10510篇 |
2012年 | 15593篇 |
2011年 | 17408篇 |
2010年 | 9960篇 |
2009年 | 8824篇 |
2008年 | 15722篇 |
2007年 | 17464篇 |
2006年 | 16948篇 |
2005年 | 16272篇 |
2004年 | 15893篇 |
2003年 | 15268篇 |
2002年 | 14789篇 |
2001年 | 22429篇 |
2000年 | 22972篇 |
1999年 | 18921篇 |
1998年 | 5236篇 |
1997年 | 4366篇 |
1996年 | 4398篇 |
1995年 | 4124篇 |
1992年 | 14415篇 |
1991年 | 15817篇 |
1990年 | 15949篇 |
1989年 | 15630篇 |
1988年 | 14308篇 |
1987年 | 14199篇 |
1986年 | 13169篇 |
1985年 | 12686篇 |
1984年 | 9394篇 |
1983年 | 8000篇 |
1982年 | 4177篇 |
1979年 | 8937篇 |
1978年 | 6382篇 |
1977年 | 5149篇 |
1976年 | 5504篇 |
1975年 | 6613篇 |
1974年 | 7419篇 |
1973年 | 7158篇 |
1972年 | 6597篇 |
1971年 | 6309篇 |
1970年 | 5887篇 |
1969年 | 5467篇 |
1968年 | 5161篇 |
1967年 | 4621篇 |
1966年 | 3963篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
V B Nakagawara 《Journal of the American Optometric Association》1988,59(12):925-928
An eye protection program is needed in occupational medicine policies. Typical eye injuries and eye accidents, as they relate to occupational accidents, justify the management advocating such a program. A recommended model for a functional eye protection program is provided and defined. 相似文献
992.
Central sensory and motor conduction in vitamin B12 deficiency. 总被引:7,自引:0,他引:7
V Di Lazzaro D Restuccia D Fogli R Nardone S Mazza P Tonali 《Electroencephalography and clinical neurophysiology》1992,84(5):433-439
Four patients with subacute combined degeneration were studied through upper and lower limb SEPs recorded with a non-cephalic reference montage and through cortical and spinal magnetic stimulation. Clinical signs were confined to the lower limbs in 3 patients; the remaining patient presented only paraesthesiae in 4 limbs. Median nerve SEPs showed a normal cervical N13 response with a significant increase of central conduction time concerning exclusively the P9-P14 interpeak interval. Central motor conduction to upper and lower limb muscles was abnormal. Nerve conduction studies provided no evidence of peripheral nerve involvement. These electrophysiological findings suggest that in vitamin B12 deficiency the higher segments of the cervical cord are usually affected first and that central sensory and motor conduction studies are sensitive methods for detecting such damage. 相似文献
993.
Disease processes in the peritoneum, omentum, and mesentery occasionally are not recognized at radiologic examination. The authors have used computed tomography (CT) to categorize the radiologic appearances of the more common abnormalities into three basic patterns: (a) solid but relatively well-defined masses, (b) cystic-appearing masses, and (c) ill-defined or infiltrative processes. The most common solid masses to affect these anatomic regions are secondary neoplasms, which are associated with enhancement of the peritoneum on contrast material-enhanced CT scans and, typically, ascites. The various cystic-appearing masses (including cystic lymphangioma, cystic mesothelioma, teratoma, and loculated ascites) and infiltrating masses (such as peritoneal mesothelioma, retractile mesenteritis, desmoid, and carcinoid) must be differentiated on the basis of clinical findings and additional imaging findings (eg, CT depiction of fat and calcium in teratomas and the radiating appearance of carcinoids). Although the CT appearances of some of the abnormalities overlap, classifying them by pattern is helpful in narrowing the range of the differential diagnosis. 相似文献
994.
We describe the types of aggressive behaviour and determine their prevalence in a sample of hospitalized elderly psychiatric patients. Data were obtained by nurse ratings of aggressive behaviour using the recently developed Rating Scale for Aggressive Behaviour in the Elderly; 90 patients were rated over a 3-d period. Nearly half the sample were at least mildly aggressive; the frequencies of some specific types of aggressive behaviour were high. In contrast, the frequency of injuries and the use of restraints and medication for aggressive behaviour were low. Some correlates of the aggressive behaviour were also analysed. 相似文献
995.
996.
997.
998.
999.
The effects of various neurotransmitters on phosphoinositide hydrolysis, mobilization of Ca2+ and release of [3H]-norepinephrine ([3H]-NE) were studied in cultures of sympathetic neurons of chick embryos. [3H]-inositol-1,4,5-triphosphate ([3H]-IP3) was increased in sympathetic neurons by acetylcholine (ACh), muscarine and serotonin (5-HT). Dopamine and norepinephrine did not stimulate phosphoinositide hydrolysis. Intracellular concentration of free Ca2+ ([Ca2+]i) was measured in Indo-1-loaded sympathetic neurons at rest and after addition of test agents. Measurements were made in the cell body and growth cone regions since Ca2+ mobilization is known to be different in different regions of the sympathetic neurons. ACh (nicotinic component was blocked by hexamethonium) and 5-HT failed to increase the [Ca2+]i, in the cell body as well as in the growth cone. The spontaneous release of [3H]-NE was not affected by ACh and 5-HT. Caffeine increased the [Ca2+]i only in the cell body but not in the growth cone and had no effect on the release of [3H]-NE. These results suggest that an IP3-insensitive but caffeine-sensitive pool of Ca2+ is present only in the somatic region of sympathetic neurons and is not coupled to the transmitter release. 相似文献
1000.
A A Abitbol J G Schwade A A Lewin K Sridhar A H Brandon A M Markoe R R Casiano P V Houdek C Serago D J Miller 《American journal of clinical oncology》1992,15(3):250-255
Seventeen patients were entered into a Phase I/II trial of concurrent hyperfractionated radiation therapy (7,440 cGy total dose; 120 cGy b.i.d.) combined with constant infusion of 5-fluorouracil (5-FU) (1,000 mg/m2/24 hours for 72 hours) and cisplatin (DDP) (50 mg/m2) for a total of three cycles. Thirteen patients had Stage IV disease; three, Stage III disease; and one, Stage II hypopharyngeal disease. Thirteen of 17 patients had positive cervical lymph nodes, and the mean size of the largest lymph node was 5.5 x 5.1 cm. The patients were not treated with planned adjunctive surgery except for one patient who had a radical neck dissection for massive, rapidly growing cervical adenopathy, which recurred promptly within 1 month before the initiation of protocol therapy. After the initial six patients were entered, mitomycin-C (Mito 8 mg/m2) was added during the second cycle. All the patients completed the planned course of radiotherapy with a median dose of 7,440 cGy and a mean dose of 7,248 cGy except for two patients who died--one from toxicity and the other, suicide. The predominant toxicity was mucositis, which was grade 3/4 in 11 of 15 patients, resulting in an average interruption of radiation therapy of 12 days. Weight loss was significant and was on the average 12% of baseline weight. Hematological toxicity was mild in the 5-FU/DDP group (only one grade 3 toxicity of six) and severe in the 5-FU/DDP/Mito-treated patients (five of eight patients having grade 3/4 toxicity including one leukopenic pneumonitis death). Additional toxicity included one parapharyngeal cellulitis, which responded to antibiotics. Noncompliance with the complex regimen was only seen in three patients. One patient refused b.i.d. radiation therapy, and one patient refused further chemotherapy after the first cycle. Additionally, one patient who had a severe ethanol withdrawal reaction during the first cycle of 5-FU/DDP did not receive further chemotherapy. The complete response rate of both primary site and neck by the protocol regimen alone was 71%. However, two patients, one from each group, did undergo salvage neck dissection, and the locoregional control is currently 73%, with a mean follow-up time of 18.4 months. The feasibility of combining hyperfractionated radiation therapy with aggressive concurrent chemotherapy was demonstrated. The response and local control rate justifies the added toxicity of concurrent chemotherapy and radiation therapy. 相似文献