全文获取类型
收费全文 | 133003篇 |
免费 | 7369篇 |
国内免费 | 761篇 |
专业分类
耳鼻咽喉 | 1344篇 |
儿科学 | 4264篇 |
妇产科学 | 3048篇 |
基础医学 | 18897篇 |
口腔科学 | 4427篇 |
临床医学 | 12032篇 |
内科学 | 30040篇 |
皮肤病学 | 3480篇 |
神经病学 | 12592篇 |
特种医学 | 3204篇 |
外国民族医学 | 2篇 |
外科学 | 12726篇 |
综合类 | 514篇 |
一般理论 | 59篇 |
预防医学 | 13071篇 |
眼科学 | 2273篇 |
药学 | 9079篇 |
中国医学 | 508篇 |
肿瘤学 | 9573篇 |
出版年
2024年 | 137篇 |
2023年 | 1204篇 |
2022年 | 2587篇 |
2021年 | 4412篇 |
2020年 | 2644篇 |
2019年 | 3730篇 |
2018年 | 4300篇 |
2017年 | 3137篇 |
2016年 | 3622篇 |
2015年 | 4057篇 |
2014年 | 5434篇 |
2013年 | 7104篇 |
2012年 | 10637篇 |
2011年 | 11190篇 |
2010年 | 6121篇 |
2009年 | 5187篇 |
2008年 | 8929篇 |
2007年 | 8935篇 |
2006年 | 8248篇 |
2005年 | 7812篇 |
2004年 | 7013篇 |
2003年 | 6338篇 |
2002年 | 5758篇 |
2001年 | 1064篇 |
2000年 | 905篇 |
1999年 | 1061篇 |
1998年 | 1022篇 |
1997年 | 825篇 |
1996年 | 711篇 |
1995年 | 594篇 |
1994年 | 569篇 |
1993年 | 456篇 |
1992年 | 550篇 |
1991年 | 404篇 |
1990年 | 413篇 |
1989年 | 358篇 |
1988年 | 359篇 |
1987年 | 295篇 |
1986年 | 296篇 |
1985年 | 243篇 |
1984年 | 253篇 |
1983年 | 205篇 |
1982年 | 205篇 |
1981年 | 164篇 |
1980年 | 168篇 |
1979年 | 158篇 |
1978年 | 126篇 |
1977年 | 114篇 |
1976年 | 107篇 |
1974年 | 108篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Carmen Guillén Ponce María Pilar Garrido López María José Molina Garrido Gema Muñoz Molina Alfredo Carrato 《Clinical & translational oncology》2007,9(1):53-55
Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually
due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal
deficiency.
We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes
insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading
the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer. 相似文献
63.
Rosangela Saga Kamikawa Marlene Fenyo Pereira Angela Fernandes Maria Inês Meurer 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2006,101(3):374-378
OBJECTIVE: To determine the location in soft tissues of the calcifications, similar to calcified carotid atheromas, that can be observed radiographically in the cervical region in panoramic radiographs. STUDY DESIGN: In each anatomic cadaver specimen preserved in formol, consisting of the head and neck, radiopaque spheres (made from gutta-percha) were positioned in anatomic structures of the cervical region that can be sites of calcification. For each anatomic structure marked in this way, panoramic radiography was performed, consisting of 17 radiographs. The images obtained were analyzed by 24 examiners who indicated which radiographs, in their opinion, presented the radiopaque reference projected in the region of bifurcation of the carotid artery. Analysis of 2 proportions from agreement and disagreement was used to determine radiopacities that could be confused in panoramic radiographs with calcified atheromas in the carotid artery. RESULTS: The results showed that 75% (18) of the examiners correctly indicated the reference in the bifurcation of the carotid artery and 79.2% (19) indicated a triticeous cartilage as calcified atheroma of the carotid artery. CONCLUSIONS: Calcified atheromas of the carotid artery are not the only features that can produce radiopaque images lateral to the panoramic radiograph; the presence of calcification in the triticeous cartilage also can induce an erroneous diagnosis of calcified carotid atheroma. 相似文献
64.
Maria G. Genkova-Papazova Maria B. Lazarova-Bakarova 《European neuropsychopharmacology》1996,6(4):285-290
Deficit in active and inhibitory avoidance behaviour has been found in pentylenetetrazole (PTZ)-kindled rats. This supports the view that memory deficit is an integral part of epilepsy. In the present study we examined the effect of the nootropic drugs piracetam and fipexide on memory deficit induced by PTZ-kindling in shuttle-box- and step-down-trained rats. The retention in piracetam- and fipexide-treated animals was significantly improved compared to the kindled controls. The mechanisms of action of the two drugs are considered. The favourable effects of nootropic drugs in cases of amnesia provoked by PTZ-kindling might be of interest in clinical practice. 相似文献
65.
66.
I M Rebeyka R A Axford-Gatley B G Bush P J del Nido D A Mickle A D Romaschin G J Wilson 《The Journal of thoracic and cardiovascular surgery》1990,99(3):475-483
The production and prevention of calcium paradox injury in myocardium was studied in a canine model of cardiopulmonary bypass with multidose, moderately hypothermic, crystalloid cardioplegic solution. During 4 1/2 hours of global ischemia, three groups of six dogs each received one of three histidine-buffered cardioplegic solutions (500 ml initially and 250 ml every 30 minutes) at 27 degrees C. Group 1 cardioplegic solution was calcium free, group 2 solution contained a trace amount of calcium chloride (70 mumols /L), and group 3 cardioplegic solution was calcium free but contained diltiazem (150 micrograms/kg body weight). Left ventricular function measured as percent control of developed pressure revealed significantly greater (p less than 0.05) recovery in groups 2 and 3. Triphenyltetrazolium chloride staining showed 35% +/- 9% (mean +/- standard error) of heart mass necrosis in group 1 versus 0% and 0.5% +/- 0.4% in groups 2 and 3, respectively (p less than 0.001). Electron microscopy revealed ultrastructural changes characteristic of calcium paradox injury in group 1 myocardium. Calcium paradox injury was produced in an in vivo model of global myocardial ischemia and multidose cardioplegia despite moderate hypothermia and non-coronary collateral flow. The addition of either trace levels of calcium or diltiazem to the cardioplegic solution was effective in preventing this injury. 相似文献
67.
To evaluate the effects of irradiation on heterotopically placed vascularized knee isografts, a single dose of 10 Gy of total-body irradiation was given to Lewis donor rats. Irradiation was delivered either 2 or 6 days prior to harvesting or subsequent transplantation, and evaluated at 1, 2, and 4 weeks after grafting. Irradiation caused endothelial depopulation of the graft artery, although vascular pedicle patency was maintained throughout the study. Bone graft viability and mineralization were normal. Dramatic changes in the bone marrow were seen that included an increase of its fat content (P less than 0.001), and a concomitant decrease in bone marrow-derived immunocompetent cells. These changes were more prominent in recipients of grafts from day -6 irradiated donor rats. Total-body irradiation did not prejudice the use of vascularized bone grafts, and exhibited an associated immunosuppresant effect over the vascular endothelium and bone marrow. This may be a further rational conditioning procedure to avoid recipient manipulation in vascularized bone allotransplantation. 相似文献
68.
A. Krödel B. Krauss H. J. Refior C. H. Siebert 《Archives of orthopaedic and trauma surgery》1990,109(3):133-138
Summary Twenty-nine patients were examined by magnetic resonance imaging for various lesions of the spine. The results of these scans were compared with those of plain radiographs, computertomographs, and radionuclide bone scans. The findings were substantiated by intraoperative or histological findings in 18 cases. The MRI scans proved to be very sensitive in the detection of a wide spectrum of morphological changes of the bone marrow of vertebral bodies. Characteristic changes of the signal patterns for inflammatory and tumorous lesions were not observed. The differentiation of these lesions will presently continue to have to be based on morphological criteria.No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this study. No funds were received in support of this study 相似文献
69.
Maria Pia Francescato P. Cok O. Radillo B. de Bernard 《Journal of human nutrition and dietetics》1988,1(5):321-327
A computer-assisted method for the registration of food intakes in real time according to a concise and simple procedure was subjected to a series of controls in order to assess precision. The method employs the 'portion' of a composite dish as unit of measure. The constancy of the portion was tested. The results show that the recipes of the diet of a subject may be stored and utilized in deferred time without loss of precision: data to be recorded in real time are then very limited. The length of period of analysis was also studied. The time of investigation should not be shorter than two weeks to obtain precise information on the feeding habits of an individual subject, whereas for a group of subjects the diary of a single day provides information of sufficient precision. 相似文献
70.
Nicoletta Desideri Isabella Sestili Maria Luisa Stein Stefano Manarini Giuseppe Dell'Elba Chiara Cerletti 《Archiv der Pharmazie》1997,330(4):100-106
6-[(4-Quinolinyl)oxy]hexanoic acids and the corresponding esters were designed and synthesized as inhibitors of the production of arachidonic acid metabolites. The inhibitory activities were assayed in vitro by evaluation of serum leukotriene B4 and thromboxane B2 production. While all 6-[(4-quinolinyl)oxy]hexanoic acids and their esters proved to be inactive, the N-alkyl-4-quinolones, obtained as by-products in their synthesis, were found to be a new class of leukotriene biosynthesis inhibitors. 相似文献