全文获取类型
收费全文 | 3900篇 |
免费 | 203篇 |
国内免费 | 84篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 139篇 |
妇产科学 | 44篇 |
基础医学 | 603篇 |
口腔科学 | 56篇 |
临床医学 | 378篇 |
内科学 | 893篇 |
皮肤病学 | 59篇 |
神经病学 | 267篇 |
特种医学 | 575篇 |
外国民族医学 | 2篇 |
外科学 | 428篇 |
综合类 | 31篇 |
一般理论 | 1篇 |
预防医学 | 182篇 |
眼科学 | 36篇 |
药学 | 269篇 |
中国医学 | 1篇 |
肿瘤学 | 190篇 |
出版年
2023年 | 24篇 |
2022年 | 29篇 |
2021年 | 51篇 |
2020年 | 29篇 |
2019年 | 35篇 |
2018年 | 46篇 |
2017年 | 44篇 |
2016年 | 59篇 |
2015年 | 62篇 |
2014年 | 94篇 |
2013年 | 114篇 |
2012年 | 168篇 |
2011年 | 143篇 |
2010年 | 124篇 |
2009年 | 131篇 |
2008年 | 136篇 |
2007年 | 230篇 |
2006年 | 131篇 |
2005年 | 150篇 |
2004年 | 131篇 |
2003年 | 127篇 |
2002年 | 146篇 |
2001年 | 112篇 |
2000年 | 114篇 |
1999年 | 110篇 |
1998年 | 118篇 |
1997年 | 102篇 |
1996年 | 68篇 |
1995年 | 78篇 |
1994年 | 62篇 |
1993年 | 54篇 |
1992年 | 68篇 |
1991年 | 68篇 |
1990年 | 76篇 |
1989年 | 100篇 |
1988年 | 83篇 |
1987年 | 65篇 |
1986年 | 64篇 |
1985年 | 88篇 |
1984年 | 51篇 |
1983年 | 34篇 |
1982年 | 43篇 |
1981年 | 24篇 |
1980年 | 34篇 |
1979年 | 39篇 |
1978年 | 22篇 |
1977年 | 29篇 |
1976年 | 26篇 |
1975年 | 24篇 |
1972年 | 17篇 |
排序方式: 共有4187条查询结果,搜索用时 15 毫秒
1.
2.
3.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1
4.
Apolipoprotein E isoforms were determined in 139 unrelated patients with retinitis pigmentosa (RP). When compared to prevalence rates for the general population in Germany, an increased prevalence was observed for phenotypes E2/E2: 10.1 vs. 1.0% (p less than 0.001), E2/E3: 19.4 vs. 12.0% (p less than 0.05), and E2/E4: 5.8 vs. 1.5% (n.s.), while the prevalence appeared to be reduced for phenotypes E3/E3: 48.9 vs. 59.8% (n.s.) E3/E4: 13.7 vs. 22.9% (p less than 0.05), and E4/E4: 2.2 vs. 2.8% (n.s.). These findings suggest that genetically determined abnormalities of plasma lipoprotein metabolism may be associated with some forms of RP. 相似文献
5.
6.
D. Chemla P. Démolis M. Thyrault D. Annane Y. Lecarpentier and JF Giudicelli 《Fundamental & clinical pharmacology》1996,10(4):393-399
Summary— The influence of local resistance and cardiac performance on peripheral blood acceleration was investigated in 14 healthy male volunteers. Steady and pulsatile flow was studied in the brachial and in the common carotid arteries, ie, two territories that exhibit marked differences in resistive characteristics. Instantaneous blood velocity (V), mean blood velocity (Vm ) and artery diameter (D) were evaluated at rest by an ultrasonic range-gated pulsed Doppler flowmeter using a double transducer probe, thus allowing the calculation of mean blood flow (Q). Mean local resistance (R) was obtained by dividing the mean arterial pressure by Q. The peak value of the local acceleration of the blood was obtained by computer-assisted calculation of the first derivative of instantaneous blood velocity (Gmax = +dV/dtmax ). Peak aortic blood acceleration (GAo) was simultaneously measured from the suprasternal notch using a pulsed Doppler velocity meter. In the brachial and the common carotid arteries, Gmax was of a similar magnitude (551 ±30 and 555 ± 44 cm/s2 , respectively) despite major differences in the respective D, Vm , Q and R values. In neither artery was there a relationship between Gmax and either resting Q or R. At the brachial artery level, Gmax was positively related to GAo ( r = 0.79, P = 0.0008). At the common carotid artery level, there was a weak, although non significant relationship between Gmax and GAo ( P = 0.08). Our results indicate that the local acceleration of peripheral blood flow in the brachial artery is related rather to upstream central impulse than to downstream hemodynamics, and suggest some regional differences in the hemodynamic determinants of the local acceleration of peripheral blood flow. 相似文献
7.
U Bergmann W K?nig W Gross-Weege B Schlüter M K?ller G Erbs F E Müller 《The Journal of trauma》1990,30(11):1372-1379
Thermal injury is known to induce dysregulation of the immune system; however, the precise mechanisms have to be clarified. We investigated the histamine release of basophil granulocytes from severely burned patients (n = 12) after stimulation with anti-IgE or the Ca-ionophore A 23187, respectively. The anti-IgE-induced basophil histamine release of all patients was reduced in comparison to healthy donors beginning at day one postburn (p.b.) (5.0 +/- 2.3% vs. 30.5 +/-3.4%), while the Ca-ionophore-induced release was not decreased before day two p.b. Basophils of patients who finally succumbed to their injuries showed poor responsiveness (to zero levels) over the total time. In contrast, the basophil releasability of surviving patients returned to nearly normal levels (fifth to seventh week p.b.). Already in the second week p.b. there was a significant difference in histamine release between survivors and nonsurvivors [e.g., days 6-9 p.b.: 23.7 +/- 4.0 vs. 6.9 +/- 2.7 (p less than 0.005) after Ca-ionophore stimulation]. The altered basophil histamine release was neither due to a diminished dose- or a delayed time-response to the stimuli nor due to differences in the basophil counts or the cellular histamine content. Our data indicate that the decrease of the basophil releasability, which may be secondary to altered signal transduction pathways in severely burned patients correlates with the clinical outcome. 相似文献
8.
Summary Postnatal formation of the Blood-Testis Barrier (BTB) in the rat was studied by either fixation in hypertonic fixative or employing lanthanum tracer. After 15 days of age, meiosis has reached different stages of spermatogenesis in differnt zones of the seminiferous cords. Only in those parts where germ cells are in the pachytene stage of meiosis do Sertoli cells form an effective barrier or tight compartment. Between 16 and 19 days of age, final formation of the BTB, which is to be found in the adult rat testis, occurs by zygotene and then leptotene stages successively entering the tight compartment. Thus, formation of a BTB by Sertoli cells does not occur synchronously along the length of the seminiferous cord but in accordance with the stage of meiosis of the associated germ cells. 相似文献
9.
10.
Modern radiologic diagnostics show a variety of pathological changes in the mediastinum, pleura, and lung but no evidence on their histogenesis. Transbronchial and transthoracal fine-needle aspiration biopsy usually cannot yield detailed diagnostic results because of its small size. Sufficient and representative material can be obtained by thoracoscopy. Video-assisted thoracoscopy allows safe and fast diagnosis of diffuse lung diseases, pleural diseases including malignant mesothelioma, indeterminate peripheral lung nodule, and mediastinal masses. This gentle diagnostic method can give invaluable information guiding further management of the thoracic injury. Video-assisted thoracoscopy is a safe and effective guiding tool if performed by experienced thoracic surgeons able to convert to thoracotomy. It is to be noted that interpretation of intraoperative findings plays a decisive role in interdisciplinary diagnostics of intrathoracal diseases. 相似文献