全文获取类型
收费全文 | 27673篇 |
免费 | 1855篇 |
国内免费 | 83篇 |
专业分类
耳鼻咽喉 | 235篇 |
儿科学 | 677篇 |
妇产科学 | 511篇 |
基础医学 | 4068篇 |
口腔科学 | 345篇 |
临床医学 | 2592篇 |
内科学 | 6676篇 |
皮肤病学 | 714篇 |
神经病学 | 2419篇 |
特种医学 | 822篇 |
外国民族医学 | 3篇 |
外科学 | 4040篇 |
综合类 | 283篇 |
一般理论 | 28篇 |
预防医学 | 2006篇 |
眼科学 | 504篇 |
药学 | 1720篇 |
1篇 | |
中国医学 | 56篇 |
肿瘤学 | 1911篇 |
出版年
2022年 | 147篇 |
2021年 | 364篇 |
2020年 | 243篇 |
2019年 | 382篇 |
2018年 | 466篇 |
2017年 | 323篇 |
2016年 | 375篇 |
2015年 | 444篇 |
2014年 | 668篇 |
2013年 | 1002篇 |
2012年 | 1460篇 |
2011年 | 1641篇 |
2010年 | 978篇 |
2009年 | 1001篇 |
2008年 | 1538篇 |
2007年 | 1716篇 |
2006年 | 1701篇 |
2005年 | 1805篇 |
2004年 | 1651篇 |
2003年 | 1579篇 |
2002年 | 1570篇 |
2001年 | 445篇 |
2000年 | 388篇 |
1999年 | 425篇 |
1998年 | 387篇 |
1997年 | 345篇 |
1996年 | 302篇 |
1995年 | 292篇 |
1994年 | 266篇 |
1993年 | 241篇 |
1992年 | 344篇 |
1991年 | 330篇 |
1990年 | 312篇 |
1989年 | 275篇 |
1988年 | 239篇 |
1987年 | 228篇 |
1986年 | 251篇 |
1985年 | 245篇 |
1984年 | 231篇 |
1983年 | 205篇 |
1982年 | 228篇 |
1981年 | 234篇 |
1980年 | 187篇 |
1979年 | 159篇 |
1978年 | 144篇 |
1977年 | 152篇 |
1976年 | 123篇 |
1975年 | 119篇 |
1974年 | 115篇 |
1973年 | 113篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
In a patient with clinical manifestations suggestive of brain malformation, CT showed lissencephaly with absent opercularization. The child had seizures but not a typical EEG of hypsarhythmia. MRI confirmed the diagnosis and showed heterotopic grey matter and abnormal basal ganglia. High grey-white matter contrast and the possibility of imaging the brain in sagittal, coronal and transverse planes make MRI the methode of choice for the evaluation of lissencephaly and other brain malformations. 相似文献
62.
BALB/c mice were bilaterally implanted with bipolar electrodes either in anterodorsal (ADH) or posteroventral hippocampus (PVH) in order to compare the effects of postsession electrical stimulation on memory processes. For each experiment, 30 s after the end of the first session, the animals were stimulated during 80 s. For both hippocampal regions, the stimulation intensity was half of the afterdischarge threshold value. Control groups were naive, ADH and PVH implanted non-stimulated animals. Different appetitive and aversive tasks were used. Subseizure stimulation never created a deficit. Depending on the region of the hippocampus stimulated and on the learning task, a retention enhancement was eventually observed. These data are in agreement with the involvement of hippocampus in initial stages of memory consolidation. Further, the subseizure stimulation permitted a functional dissociation between the two hippocampal regions. Both regions seemed involved in the integration of information, but the anterodorsal part would be rather related to behavioral inhibition, while the posteroventral part would have the capacity to induce an arousal state allowing behavioral flexibility. 相似文献
63.
Elke Wezenberg Robert Jan Verkes Ge S F Ruigt Wouter Hulstijn Bernard G C Sabbe 《Neuropsychopharmacology》2007,32(6):1272-1283
Ampakines act as positive allosteric modulators of AMPA-type glutamate receptors and facilitate hippocampal long-term potentiation (LTP), a mechanism associated with memory storage and consolidation. The present study investigated the acute effects of farampator, 1-(benzofurazan-5-ylcarbonyl) piperidine, on memory and information processes in healthy elderly volunteers. A double-blind, placebo-controlled, randomized, cross-over study was performed in 16 healthy, elderly volunteers (eight male, eight female; mean age 66.1, SD 4.5 years). All subjects received farampator (500 mg) and placebo. Testing took place 1 h after drug intake, which was around Tmax for farampator. Subjects performed tasks assessing episodic memory (wordlist learning and picture memory), working and short-term memory (N-back, symbol recall) and motor learning (maze task, pursuit rotor). Information processing was assessed with a tangled lines task, the symbol digit substitution test (SDST) and the continuous trail making test (CTMT). Farampator (500 mg) unequivocally improved short-term memory but appeared to impair episodic memory. Furthermore, it tended to decrease the number of switching errors in the CTMT. Drug-induced side effects (SEs) included headache, somnolence and nausea. Subjects with SEs had significantly higher plasma levels of farampator than subjects without SEs. Additional analyses revealed that in the farampator condition the group without SEs showed a significantly superior memory performance relative to the group with SEs. The positive results on short-term memory and the favorable trends in the trail making test (CTMT) are interesting in view of the development of ampakines in the treatment of Alzheimer's disease and schizophrenia. 相似文献
64.
A unique example of a gingival salivary gland choristoma together with a gingival cyst is described in a human autopsy specimen of periodontal tissues. A choristoma is a tumor-like growth which is derived from primordial cells which have been displaced from their original tissue or organ. Only 6 other examples of the gingival salivary gland choristoma have been described in the world literature. 相似文献
65.
66.
M. Estryn-Behar B. Kapitaniak M. C. Paoli E. Peigne A. Masson 《International archives of occupational and environmental health》1992,64(2):131-139
Summary The aim of this study was to evaluate the level of physical capacity in a female hospital population of Paris and its suburbs. A total of 1505 women working in the selected departments filled in a questionnaire concerning their working conditions, life habits and health and also attended a medical examination. The effort test performed consisted in flexing the legs 20 times with the chest held straigt, in 40 s. The heart rates were measured for the first, the second and the third minutes of recovery (first 15 s multiplied by 4). The blood pressure was measured just after the heart rate, for the first and the third minute. Recovery indices have been constituted from the results. The respective weights of anthropometric and sociodemographic risk factors for recovery indices were studied in multiple logistic regression models. The classification enables us to consider about 25%–30% of our population as having a satisfactory physical capacity, about 26%–27% as having an acceptable capacit, and about 24%–27% as having a weak capacity. About 21% of the population presented an excessive pressure reaction and 44% a questionable pressure reaction. Our results concerning the level of physical capacity of the female nursing staff should be taken into account especially in the future planning of work loads and architectural choices, which must avoid excessive physical burdens in relation to this level. An improvement in the level of physical capacity could be envisaged as well. 相似文献
67.
Marsha Bernard Kuhar 《AAOHN journal》2002,50(8):360-364
1. The Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATPIII) will significantly increase the number of Americans treated for hypercholesterolemia. 2. The ATPIII focuses on lowering low density lipoprotein cholesterol as a primary initiative and using exercise, diet, and pharmacotherapy as a means for lowering coronary heart disease and risks. 3. The new guidelines list low density lipoprotein cholesterol levels of less than 100 mg/dL as optimal for all clients. 4. The ATPIII places increased attention on high triglyceride levels (> 200 mg/dL) and on early detection and appropriate aggressive treatment for clients at risk for coronary heart disease and events. 相似文献
68.
69.
Marko Simunovic Eddy Rempel Marc-Erick Thériault Angela Coates Timothy Whelan Eric Holowaty Bernard Langer Mark Levine 《Canadian journal of surgery》2006,49(4):251-258
BACKGROUND: There is a lack of information from Canadian hospitals on the role of hospital characteristics such as procedure volume and teaching status on the survival of patients who undergo major cancer resection. Therefore, we chose to study these relationships using data from patients treated in Ontario hospitals. METHODS: We used the Ontario Cancer Registry from calendar years 1990-2000 to obtain data on patients who underwent surgery for breast, colon, lung or esophageal cancer or who underwent major liver surgery related to a cancer diagnosis between 1990 and 1995 in order to assess the influence of volume of procedures and teaching status of hospitals on in-hospital death rate and long-term survival. For each disease site and before observing patient outcomes data, volume cut-off points were selected to create volume groups with similar numbers of patients. Teaching hospitals were those directly affiliated with a medical school. Logistic regression and proportional hazards models were used to consider the clustering of data at the hospital level and to assess operative death and long-term survival. We also used 4 measures to gauge the degree of procedure regionalization across the province including (1) the number of hospitals performing a procedure; (2) the percentage of patients treated in teaching hospitals; (3) the percentage of rural patients treated in higher volume procedure hospitals; and (4) median distances travelled by patients to receive care. RESULTS: The number of patients in our cohorts who underwent resection of the breast, colon, lung, esophagus or liver was 14 346, 8398, 2698, 629 and 362, respectively. Surgery in a high-volume versus a low-volume hospital did not have a statistically significant influence on the odds of operative death for patients who underwent colon, liver, lung or esophageal cancer resection. The risk of long-term death was increased in low-volume versus high-volume hospitals for patients who underwent resection of the breast (hazard ratio [HR] 1.2, 95% confidence interval [95% CI] 1.0-1.4, p < 0.05), lung (HR 1.3, 95% CI 1.1-1.6, p < 0.01) and liver (HR 1.7, 95% CI 1.0-2.7, p = 0.04). There were no significant differences in the odds of operative (in-hospital) death or risk of long-term death among patients treated in teaching compared with nonteaching hospitals. There was more regionalization of liver, lung and esophageal operations versus breast and colon operations. CONCLUSIONS: Increased hospital procedure volume correlated with improved longterm survival for patients in Ontario who underwent some, but not all, cancer resections, whereas hospital teaching status had no significant impact on patient outcomes. Across the province, further regionalization of care may help improve the quality of some cancer procedures. 相似文献
70.