全文获取类型
收费全文 | 2801890篇 |
免费 | 376210篇 |
国内免费 | 43235篇 |
专业分类
耳鼻咽喉 | 36651篇 |
儿科学 | 89167篇 |
妇产科学 | 74434篇 |
基础医学 | 427169篇 |
口腔科学 | 76541篇 |
临床医学 | 283659篇 |
内科学 | 558357篇 |
皮肤病学 | 57291篇 |
神经病学 | 229915篇 |
特种医学 | 106839篇 |
外国民族医学 | 804篇 |
外科学 | 408462篇 |
综合类 | 108728篇 |
现状与发展 | 4篇 |
一般理论 | 960篇 |
预防医学 | 242547篇 |
眼科学 | 74785篇 |
药学 | 243183篇 |
12篇 | |
中国医学 | 52060篇 |
肿瘤学 | 149767篇 |
出版年
2019年 | 32642篇 |
2018年 | 40933篇 |
2017年 | 35260篇 |
2016年 | 35970篇 |
2015年 | 39265篇 |
2014年 | 49055篇 |
2013年 | 68849篇 |
2012年 | 88859篇 |
2011年 | 94899篇 |
2010年 | 63315篇 |
2009年 | 65847篇 |
2008年 | 87151篇 |
2007年 | 88334篇 |
2006年 | 88368篇 |
2005年 | 85954篇 |
2004年 | 85463篇 |
2003年 | 81273篇 |
2002年 | 79495篇 |
2001年 | 126098篇 |
2000年 | 126504篇 |
1999年 | 111136篇 |
1998年 | 38232篇 |
1997年 | 34772篇 |
1996年 | 34497篇 |
1995年 | 33733篇 |
1994年 | 32119篇 |
1993年 | 29865篇 |
1992年 | 90602篇 |
1991年 | 88567篇 |
1990年 | 85678篇 |
1989年 | 82449篇 |
1988年 | 76824篇 |
1987年 | 75125篇 |
1986年 | 71622篇 |
1985年 | 68471篇 |
1984年 | 51629篇 |
1983年 | 44789篇 |
1982年 | 28863篇 |
1981年 | 25915篇 |
1979年 | 48849篇 |
1978年 | 35026篇 |
1977年 | 30044篇 |
1976年 | 28455篇 |
1975年 | 29509篇 |
1974年 | 35768篇 |
1973年 | 34441篇 |
1972年 | 31976篇 |
1971年 | 29723篇 |
1970年 | 27540篇 |
1969年 | 25382篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
R E Dales A Mehdizadeh S D Aaron K L Vandemheen J Clinch 《The European respiratory journal》2006,28(2):319-322
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction. 相似文献
102.
L Bernardi A Schneider L Pomidori E Paolucci A Cogo 《The European respiratory journal》2006,27(1):165-171
A very high ventilatory response to hypoxia is believed necessary to reach extreme altitude without oxygen. Alternatively, the excessive ventilation could be counterproductive by exhausting the ventilatory reserve early on. To test these alternatives, 11 elite climbers (2004 Everest-K2 Italian Expedition) were evaluated as follows: 1) at sea level, and 2) at 5,200 m, after 15 days of acclimatisation at altitude. Resting oxygen saturation, minute ventilation, breathing rate, hypoxic ventilatory response, maximal voluntary ventilation, ventilatory reserve (at oxygen saturation = 70%) and two indices of ventilatory efficiency were measured. Everest and K2 summits were reached 29 and 61 days, respectively, after the last measurement. Five climbers summited without oxygen, the other six did not, or succeeded with oxygen (two climbers). At sea level, all data were similar. At 5,200 m, the five summiters without oxygen showed lower resting minute ventilation, breathing rate and ventilatory response to hypoxia, and higher ventilatory reserve and ventilatory efficiency, compared to the other climbers. Thus, the more successful climbers had smaller responses to hypoxia during acclimatisation to 5,200 m, but, as a result, had greater available reserve for the summit. A less sensitive hypoxic response and a greater ventilatory efficiency might increase ventilatory reserve and allow sustainable ventilation in the extreme hypoxia at the summit. 相似文献
103.
M Bernasconi P N Chhajed F Gambazzi L Bubendorf H Rasch S Kneifel M Tamm 《The European respiratory journal》2006,27(5):889-894
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy. 相似文献
104.
105.
106.
107.
108.
T. Svara M. Gombac M. Vrecl P. Juntes R. Kostanjsek A. Pogacnik M. Pogacnik 《Transboundary and Emerging Diseases》2006,53(1):26-29
Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 ± 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin‐embedded tissues revealed the presence of the virus‐like particles with an average diameter between 70 and 90 nm. 相似文献
109.
110.
Systems of care (SOCs) have been developed throughout the country to meet the needs of children with severe emotional disturbances (SED) and their families. In these SOCs, multiple agencies and disciplines are expected to work together with informal community supports to address families' needs (Stroul & Friedman, 1986a). A review of the literature on the impact of SOCs suggests: (a) communities' service delivery systems change; and (b) children experience modest improvements in symptomatology and functioning. At the same time, little is known about (a) which components of the SOC approach, at what levels, are necessary to impact child and family outcomes; (b) the degree to which SOCs affect other family members, beyond the target child; and (c) the impact of community contexts and supports in SOCs. Future research should improve measurement of key SOC constructs, examine the relation between specific levels of implementation and outcomes for the entire family, and investigate the impact of broader community systems and supports on families within SOCs. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 655–674, 2004. 相似文献