全文获取类型
收费全文 | 2180447篇 |
免费 | 175967篇 |
国内免费 | 13676篇 |
专业分类
耳鼻咽喉 | 29825篇 |
儿科学 | 66767篇 |
妇产科学 | 61202篇 |
基础医学 | 308313篇 |
口腔科学 | 59874篇 |
临床医学 | 199567篇 |
内科学 | 421344篇 |
皮肤病学 | 47676篇 |
神经病学 | 176553篇 |
特种医学 | 84628篇 |
外国民族医学 | 704篇 |
外科学 | 325008篇 |
综合类 | 72665篇 |
现状与发展 | 44篇 |
一般理论 | 708篇 |
预防医学 | 170563篇 |
眼科学 | 51435篇 |
药学 | 160399篇 |
96篇 | |
中国医学 | 11449篇 |
肿瘤学 | 121270篇 |
出版年
2021年 | 20793篇 |
2019年 | 19482篇 |
2018年 | 25856篇 |
2017年 | 20371篇 |
2016年 | 22414篇 |
2015年 | 26805篇 |
2014年 | 37082篇 |
2013年 | 51761篇 |
2012年 | 70489篇 |
2011年 | 74826篇 |
2010年 | 44364篇 |
2009年 | 41349篇 |
2008年 | 67030篇 |
2007年 | 71109篇 |
2006年 | 71448篇 |
2005年 | 69698篇 |
2004年 | 65308篇 |
2003年 | 62477篇 |
2002年 | 59945篇 |
2001年 | 99105篇 |
2000年 | 101544篇 |
1999年 | 85527篇 |
1998年 | 25952篇 |
1997年 | 23741篇 |
1996年 | 23243篇 |
1995年 | 22058篇 |
1994年 | 20317篇 |
1993年 | 18657篇 |
1992年 | 65642篇 |
1991年 | 63002篇 |
1990年 | 60859篇 |
1989年 | 58161篇 |
1988年 | 53929篇 |
1987年 | 52713篇 |
1986年 | 49598篇 |
1985年 | 47525篇 |
1984年 | 36414篇 |
1983年 | 30889篇 |
1982年 | 19242篇 |
1979年 | 34127篇 |
1978年 | 24267篇 |
1977年 | 20271篇 |
1976年 | 18915篇 |
1975年 | 19854篇 |
1974年 | 24355篇 |
1973年 | 23470篇 |
1972年 | 22189篇 |
1971年 | 20351篇 |
1970年 | 19401篇 |
1969年 | 18370篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A lawsuit directed by parents at a day care program following an outbreak of infectious disease would most likely be based on the legal theory of negligence--the failure to exercise due care as required by circumstances. In the determination of liability for infectious diseases in child day care, the element of causation is most critical. Did the day care facility's actions or failure to act cause the harm? Another important question is whether an infectious disease can be occupational and under what circumstances. Although worker's compensation laws initially had no provisions for occupational disease, now all states recognize responsibility for them. Awareness of potential problems with legal liability and establishment of procedures to minimize risk are important for day care providers, public health officials, clinicians, and parents. 相似文献
992.
The case reported here demonstrates the importance of considering the possibility of occult malignancy in young patients presenting with extensive or migratory thromboses in atypical locations that appear resistant to standard therapy. Suspicion for malignancy-related thrombosis is heightened by the absence of known precipitating causes and by a negative family history of thrombosis. The search for the responsible underlying neoplasm can be frustrating, but diagnosis and successful treatment of the tumor remain the keys to controlling the abnormal thrombotic state. 相似文献
993.
994.
E.P. WALKER P.H. BUTLER J.W. PICKERING W.A. DAY R. FRASER C.N. VAN HALEWYN 《The British journal of dermatology》1989,121(2):217-223
We report histological changes in four patients with port wine stains treated with 578 nm yellow light from a high power copper vapour laser. Histology showed that selective damage occurred to the ectatic blood-vessels in the dermis, without haemorrhage and damage to non-vascular structures, and without scarring. The initial damage to the overlying epidermis was not permanent, and the damaged ectatic vessels returned to normal size or were completely necrosed and replaced by collagen. 相似文献
995.
Reserpine enhances amphetamine stereotypies without increasing amphetamine-induced changes in striatal dialysate dopamine 总被引:4,自引:0,他引:4
Indirect evidence suggests that amphetamine (AMPH) releases dopamine (DA) from an extravesicular, cytoplasmic pool. Disruption of vesicular DA storage by reserpine has been hypothesized to increase the concentration of extravesicular DA available for release by AMPH, which is consistent with the observation that reserpine does not prevent but augments the behavioral response to AMPH. In order to more directly test this hypothesis, the in vivo microdialysis technique was used to concurrently examine the behavioral and striatal dopaminergic response to AMPH (1.25 or 2.5 mg/kg) 24 h following reserpine pretreatment (2.5 mg/kg). Reserpine decreased tissue levels of DA by approximately 90% and reduced baseline dialysate DA concentrations by approximately 80%. Reserpine augmented the behavioural effects of AMPH, particularly increasing the occurrence and intensity of stereotypies. In contrast, reserpine did not alter the amount or duration of AMPH-induced DA release. This observation confirms that DA release by AMPH does not depend on vesicular stores but is inconsistent with the hypothesis that augmentation or behaviour by reserpine results from increased striatal DA release. 相似文献
996.
The authors compared children (ages 7-13 years) of unipolar depressed mothers with children of nondepressed psychiatric patients, of nondepressed medical patients, and of nondepressed mothers in the community. The children's adjustment was rated by clinicians on the Child Adjustment Schedule and by the mothers on the Child Behavior Checklist. The highest proportion of clinically significant problems was found in the children of the depressed mothers. However, the overlap between the problems of these children and those of the children of the nondepressed psychiatric patients calls into question the formulation that children's adjustment difficulties are specific to parental depression. 相似文献
997.
998.
Thirty-four epileptic patients, aged 9 to 36, were submitted to A/EEG between May 1987 and July 1988. All patients had a thorough clinical and EEG work-up including long-term conventional EEG, afternoon polygraphic sleep recording and, in some cases, full-night EEG and video monitoring. Patients were divided into 2 groups: group I included 19 patients (18 with symptomatic partial epilepsy (SPE) and 1 with idiopathic generalized epilepsy (IGE) in whom no seizure had ever been recorded in spite of EEG recordings averaging a total of 16 hrs 10 min, awake and asleep); group II included 15 subjects (6 with SPE, 5 with IGE, 3 with symptomatic GE and 1 with undetermined epilepsy) in whom one or several seizures had been recorded. A/EEG was performed in order to: 1) obtain better clinical and EEG characterization of seizures, 2) study the circadian distribution of seizures, 3) verify the efficacy of drug treatment and, 4) establish the epileptic or non-epileptic nature of some ictal events. The results of A/EEG were considered positive in 52.63% of group I patients and in 93.33% of group II patients. The authors discuss the specific advantages of A/EEG vs conventional EEG: recording of seizures with random occurrence, of seizures accompanied by falls, checking the remission of seizures. 相似文献
999.
Out of 24 patients with laryngeal papillomatosis 6 (5 female, 1 male) suffered from repeated relapses and underwent long-term treatment with alpha-IFN-therapy. Age at onset of the disease: 1 5/12-16 2/12 years. Duration of illness: 1-7 years, with several relapses were treated surgically and with laser-coagulation. Three out of 6 patients had a tracheal cannula and were cauterized by podophylline at 2-4 week intervals. IFN was given in dosages of 5-20 X 10(4) U/kg 2 or 3 times a week. IFN-dosage for each patient was determined using the induction kinetics of (2'-5')-oligo(A)synthetase (OAS) in the mononuclear cells of the circulating blood of patients with laryngeal papillomatosis. A continuous effect could be achieved by the dose of IFN determined in the described way always before OAS activity decreased to its initial level. All 6 patients responded favorably to the alpha-IFN-therapy. Two patients treated only with IFN showed remission without relapses. In 2 cases IFN was successfully used to prevent relapses after surgical treatment and laser-coagulation. In 2 patients with papillomatosis extending into the main bronchi the disease could only be brought to a standstill, i.e. it was not necessary to remove the papillomas. Two out of 3 patients with laryngeal papillomatosis could be decannulated. Long-term therapy following the above described principles is efficient and without significant side-effects. Three patients are in treatment for more than 3 10/12 years. 相似文献
1000.