全文获取类型
收费全文 | 1496篇 |
免费 | 139篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 73篇 |
妇产科学 | 15篇 |
基础医学 | 167篇 |
口腔科学 | 29篇 |
临床医学 | 169篇 |
内科学 | 279篇 |
皮肤病学 | 6篇 |
神经病学 | 126篇 |
特种医学 | 172篇 |
外国民族医学 | 3篇 |
外科学 | 185篇 |
综合类 | 26篇 |
预防医学 | 145篇 |
眼科学 | 35篇 |
药学 | 112篇 |
中国医学 | 3篇 |
肿瘤学 | 79篇 |
出版年
2022年 | 14篇 |
2021年 | 37篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 38篇 |
2017年 | 30篇 |
2016年 | 22篇 |
2015年 | 31篇 |
2014年 | 30篇 |
2013年 | 43篇 |
2012年 | 47篇 |
2011年 | 78篇 |
2010年 | 35篇 |
2009年 | 39篇 |
2008年 | 48篇 |
2007年 | 59篇 |
2006年 | 52篇 |
2005年 | 46篇 |
2004年 | 34篇 |
2003年 | 42篇 |
2002年 | 32篇 |
2001年 | 24篇 |
2000年 | 29篇 |
1999年 | 30篇 |
1998年 | 51篇 |
1997年 | 69篇 |
1996年 | 46篇 |
1995年 | 42篇 |
1994年 | 43篇 |
1993年 | 31篇 |
1992年 | 28篇 |
1991年 | 22篇 |
1990年 | 24篇 |
1989年 | 37篇 |
1988年 | 32篇 |
1987年 | 27篇 |
1986年 | 31篇 |
1985年 | 32篇 |
1984年 | 21篇 |
1983年 | 14篇 |
1982年 | 20篇 |
1980年 | 13篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 14篇 |
1975年 | 9篇 |
1973年 | 16篇 |
1971年 | 18篇 |
1968年 | 9篇 |
1967年 | 11篇 |
排序方式: 共有1644条查询结果,搜索用时 15 毫秒
1.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
2.
Chronic obstructive pulmonary disease is one of the most significant chronic illnesses of adults. Comprehensive care of the affected patient requires the medical-surgical nurse to have knowledge of the disease process, collaborative management, and nursing care based on research and current practice guidelines. 相似文献
3.
Paediatric dacryocystorhinostomy 总被引:1,自引:0,他引:1
KN Hakin FRCS FRCOphth TJ Sullivan FRACO FRACS A Sharma FCOphth † RAN Welham FRCS FCOphth † 《Clinical & experimental ophthalmology》1994,22(4):231-235
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease. 相似文献
4.
5.
6.
C V Patrick Onyeaka Christos Alexiou Gaetano Rocco David N Hopkinson S Kim Suvarna Peter C Braidley Tim J Locke 《The Journal of heart and lung transplantation》2005,24(8):1140-1142
Transplant pneumonectomy is a rarely performed procedure. It is occasionally carried out in the course of retransplantation. To our knowledge, resection of a transplanted lung without its replacement and with successful outcome in the adult has not been previously reported. We present a case of elective left transplant pneumonectomy in a 38-year-old man 6 years after left single-lung transplant. At 12 months after resection, the patient remains well, with good exercise tolerance. 相似文献
7.
8.
Seven elite boardsailors reporting nonradiating low back pain without leg pain during sailing volunteered for detailed examination. In these subjects, the onset of pain was limited to those occasions when sailing positions were held for a significant period of time, e.g., close hauled sailing or in light winds. No pain was described at any other time. The determination of possible antecedent factors was based on the results of clinical assessment, radiological evaluation, and computer tomography (CT) scanning. Apart from limited flexibility in some subjects, the clinical examination of these athletes was normal; CT changes in this group were limited to disc protrusions and bulges, and pars interarticularis defects. Despite the small number of subjects in the present report, it appears that the frequency of these problems exceeds that in the normal population. It may be possible to suggest that risk factors such as body position during prolonged sailing, particularly under light wind conditions without a harness, and limited flexibility may be associated with the radiological findings and may be implicated in the presence of low back pain, although further investigations appears warranted. 相似文献
9.
Epidemiologic evidence for early onset of mental disorders and higher risk of drug abuse in young adults 总被引:8,自引:0,他引:8
K A Christie J D Burke D A Regier D S Rae J H Boyd B Z Locke 《The American journal of psychiatry》1988,145(8):971-975
Data from the National Institute of Mental Health (NIMH) Epidemiologic Catchment Area Program, an epidemiologic survey of five communities, showed that four major disorders commonly begin in late adolescence or young adulthood. The median age at onset for anxiety disorders is 15 years; for major depressive episode, 24 years; for drug abuse or dependence, 19 years; and for alcohol abuse or dependence, 21 years. Findings also suggest that for respondents 18-30 years old, having a major depressive episode or anxiety disorder doubles the risk for later drug abuse or dependence. 相似文献
10.
Kenneth W. Locke Robert W. Dunn John W. Hubbard Cheri L. Vanselous Michael Cornfeldt Stuart Fielding Joseph T. Strupczewski 《Drug development research》1990,19(3):239-256
HP 818 (1-benzoyl-6-fluoro-3-(1-methyl-4-piperidinyl)-1H-indazole) exhibits the profile of a potent nonnarcotic analgesic with neuroleptic properties. HP 818 blocks the effects of chemical (phenylquinone), pressure (tail clip), and radiant heat (tail flick) painful stimuli in mice (ED50 values of 0.3, 1.2, and 4.1 mg/kg s.c., respectively). This compound displays antinociceptive activity by the subcutaneous, oral, and intravenous routes of administration. It is also effective in the shock titration assay in squirrel monkeys and in a model of surgically induced pain. The rank order of potency of HP 818 and several other standard compounds in these tests for analgesia was Innovar > fentanyl > HP 818 > codeine > droperidol. In addition to its antinociceptive effects, HP 818 possesses neuroleptic properties. It is active in the climbing mouse, pole climb avoidance, and intracranial self-stimulation assays (ED50 values of 1.8, 1.7, and 2.5 mg/kg i.p., respectively). Moreover, HP 818 inhibits amphetamine- and apomorphine-induced stereotypy, indicative of D2-dopaminergic blocking properties. HP 818, unlike typical neuroleptic agents, does not induce supersensitivity to the effects of apomorphine when administered chronically in mice. In contrast to the clinical standard neuroleptanalgesic Innovar, HP 818 (1.0–3.0 mg/kg i.v.) produces no significant cardiovascular or respiratory changes in the anesthetized dog. Thus, HP 818 is potentially an effective presurgical medication due to its nonnarcotic analgesic activity and sedative neuroleptic effects, along with its lack of limiting cardiorespiratory side effects. 相似文献