全文获取类型
收费全文 | 2685篇 |
免费 | 46篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 46篇 |
妇产科学 | 268篇 |
基础医学 | 424篇 |
口腔科学 | 38篇 |
临床医学 | 127篇 |
内科学 | 789篇 |
皮肤病学 | 39篇 |
神经病学 | 110篇 |
特种医学 | 52篇 |
外科学 | 356篇 |
综合类 | 9篇 |
预防医学 | 120篇 |
眼科学 | 16篇 |
药学 | 229篇 |
中国医学 | 9篇 |
肿瘤学 | 74篇 |
出版年
2023年 | 5篇 |
2021年 | 7篇 |
2020年 | 10篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 19篇 |
2013年 | 54篇 |
2012年 | 133篇 |
2011年 | 208篇 |
2010年 | 95篇 |
2009年 | 32篇 |
2008年 | 171篇 |
2007年 | 234篇 |
2006年 | 265篇 |
2005年 | 146篇 |
2004年 | 206篇 |
2003年 | 190篇 |
2002年 | 204篇 |
2001年 | 135篇 |
2000年 | 182篇 |
1999年 | 121篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1992年 | 5篇 |
1988年 | 6篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1971年 | 4篇 |
1970年 | 8篇 |
1969年 | 8篇 |
1968年 | 5篇 |
1967年 | 12篇 |
1965年 | 6篇 |
1959年 | 6篇 |
1924年 | 5篇 |
1914年 | 4篇 |
排序方式: 共有2732条查询结果,搜索用时 15 毫秒
1.
2.
A study of 52 middle-aged males with essential hypertension, unaccompanied by cardiovascular disorders, is reported. The patients were divided into 2 groups with respect to the type of treatment they received: 30 patients on beta-adrenoblockers and 22 patients on methyldopa. The patients were treated continuously for 2 years under one-dimensional echocardiographic control. The greatest drop in arterial blood pressure and ventricular septum thickness was seen within the first 6 months of treatment, while posterior-wall hypertrophy disappeared altogether. Although there was no further drop in blood pressure after 6 months, the thickness of the ventricular septum remained reduced for at least 2 years. Regression of left-ventricular hypertrophy was not accompanied with any deterioration of left-ventricular performance, nor was it related to additional use of vasodilators. 相似文献
3.
4.
Chicks from a high and low feather pecking line of laying hens differ in apomorphine sensitivity 总被引:2,自引:0,他引:2
van Hierden YM Koolhaas JM Kost'ál L Výboh P Sedlacková M Rajman M Juráni M Mechiel Korte S 《Physiology & behavior》2005,84(3):471-477
Proactive rodents show a larger behavioral response to apomorphine (APO) than reactive copers, suggesting a more sensitive DA system in proactive individuals. Previously, chicks from a high feather pecking (HFP) and low feather pecking line (LFP) have been suggested to display a proactive and reactive coping strategy, respectively. Therefore, at approximately 4 weeks of age, the behavior of 48 LFP and 48 HFP chicks in response to an APO injection was studied using an open field. Another objective of the present study was to determine whether behavioral variation (in an open field) between HFP and LFP birds, after APO injection, is also reflected by variation of D(1) and D(2) receptor densities in the brain. Receptor binding capacities were assessed by measuring specific binding of tritiated D(1) and D(2) receptor ligands in different regions of the brain of control HFP and LFP chicks. In the present study, it is shown that indeed HFP chicks display a more enhanced behavioral response to acute APO treatment (0.5 mg/kg BW) than LFP birds in an open field. This difference was not reflected by variation of D(1) and D(2) receptor densities in the brain between both lines. 相似文献
5.
Lonský V Mand'ák J Kubícek J Volt M Procházka E Dominik J 《Acta medica (Hradec Králové) / Universitas Carolina, Facultas Medica Hradec Králové》2005,48(2):95-98
The very large patient (weight 142 kg, height 197 cm, body surface 2.76 m2) was referred to acute operation with dissecting type A ascending aortic aneurysm. The calculated blood flow was 6.63 l/min. To anticipate potential difficulties with perfusion and oxygenation two oxygenators connected in parallel were incorporated into the circuit. Bentall procedure with ACB to the RCA was performed. The perfusion was uneventful. Bypass time was 259 minutes, cross clamp time 141 minutes, circulatory arrest 7 minutes. The highest oxygenators gas flow was 2.6 l/min with maximum FiO2 0.42. The use of two in parallel connected oxygenators is a very effective, easy and safe method in such extreme perfusions, offering to the perfusionist a great reserve of oxygenator output. 相似文献
6.
L. Janský P. Šrámek J. Šavlíková B. Uličný H. Janáková K. Horký 《European journal of applied physiology》1996,74(1-2):148-152
The purpose of this study was to determine whether or not repeated short-term cold water immersions can induce a change in the activity of the sympathetic nervous system and, consequently, in cardiovascular functions in healthy young athletes. Changes in some plasma hormone concentrations were also followed. A single cold water immersion (head-out, at 14°C, for 1 h) increased sympathetic nervous system activity, as evidenced by a four-fold increase (P < 0.05) in plasma noradrenaline concentration. Plasma adrenaline and dopamine concentrations were not increased significantly. Plasma renin-angiotensin activity was reduced by half (P < 0.05) during immersion but plasma aldosterone concentration was unchanged. Stimulation of the sympathetic nervous system during immersion did not induce significant changes in heart rate, but induced peripheral vasoconstriction (as judged from a decrease in skin temperature) and a small increase (by 10%) in systolic and diastolic blood pressures. No clear change in reactivity of the sympathetic nervous system was observed due to repeated cold water immersions (three times a week, for 6 weeks). Neither the plasma renin-angiotensin activity, aldosterone concentration nor cardiovascular parameters were significantly influenced by repeated cold water immersions. A lowered diastolic pressure and an increase in peripheral vasoconstriction were observed after cold acclimation, however. Evidently, the repeated cold stimuli were not sufficient to induce significant adaptational changes in sympathetic activity and hormone production. 相似文献
7.
Coprological examination of 40 Apodemus mystacinus Danford and Alston 1877 from Jordan revealed oocysts of three species of genus Eimeria. Two species are described as new. Eimeria zuhairamri sp. n. has broadly ellipsoidal oocysts 29.6 (27.0–34.0)×23.3 (22.0–25.0) m with distinctly granulated wall and oocyst residuum. Endogenous development occurs in jejunum and ileum. Eimeria alorani sp. n. has oocysts 26.9 (23.0–29.0)×19.3 (18.0–22.0) m with smooth wall and absent residuum. Endogenous development is confined to the caecum. The third species, developing in jejunum, has oocysts morphologically indistinguishable from Eimeria uptoni. The identity of E. uptoni and the taxonomy of Eimeria of Apodemus are discussed. 相似文献
8.
Stancíková M Svík K Istok R Rovenský J Velebný V 《International journal of tissue reactions》2004,26(1-2):9-16
Hyaluronan, or hyaluronic acid (HA), is an essential component of extracellular matrices. HA of appropriate molecular weight and concentration can induce osteoblast differentiation and bone formation in vitro. The aim of our study was to evaluate the effects of HA of different molecular weights on ovariectomy (OVX)-induced bone loss in rats. Adult female Sprague Dawley rats were subjected to bilateral OVX or sham surgical procedure (sham). OVX rats were treated with: HA of molecular weight of 0.75 MDa at a dose of 1 mg/kg/day and with HA of molecular weight of 1.62 MDa at a dose of both 0.5 mg/kg/day and 1 mg/kg/day. HA was applied orally once a day during the 8-week period after ovariectomy. Body weight, urinary pyridinoline (Pyr), deoxypyridinoline (DPyr) corrected for urinary creatinine, serum nitrite/nitrate concentrations and whole body and femoral bone mineral density (BMD) were measured. HA treatment had no effect on the body weight gain in OVX rats. Excretion of urinary Pyr and Dpyr significantly increased in OVX rats compared to sham controls. The higher molecular weight HA (1.62 MDa) significantly reduced urinary Pyr and DPyr concentrations measured on day 28 after ovariectomy (p < 0.001). Serum concentrations of nitric oxide metabolites, nitrite/nitrate significantly decreased in OVX rats in comparison with sham controls (p < 0.001). HA of both 0.75 MDa and 1.62 MDa molecular weights significantly enhanced serum nitrite/nitrate concentrations in OVX rats. There was a clear reduction of whole body and femoral BMD in untreated OVX rats. The higher molecular weight HA decreased both whole body and femoral BMD loss. Our results show that orally applied HA of high molecular weight (1.62 MDa) inhibits bone resorption and provides a protective effect on bone density in ovariectomized rats. 相似文献
9.
Jaros E Príborský J Klein L 《Acta medica (Hradec Králové). Supplementum Universitas Carolina, Facultas Medica Hradec Králové》1999,42(2):61-63
Keloid and hypertrophic scars are relatively frequent not wanted consequences of surgical treatment. 145 patients with unsatisfactory skin healing were treated in our department during last 5 years. When compared with corticotherapy and laser-therapy kryotherapy is very effective method. There were outstanding results with combination of cryotherapy and corticotherapy. 相似文献
10.
Stem cells exhibit unique properties and hold high therapeutic promise, but factors influencing their differentiation after transplantation need to be recognized and defined for this promise to be fully met. Here, we demonstrate that endogenous colony-forming unit spleen (CFU-S) colonies are not generated in lethally irradiated mice transplanted with neural stem cells obtained from brain tissue of syngeneic donors. We investigated the proportion of transplanted neural stem cells that contributed to hematopoietic reconstitution and compared the distribution of transplanted cells in nonsplenectomized to that of splenectomized mice following sublethal whole-body irradiation. We also used clonogenic assays, colony assays, and histochemical analyses to explore conditions under which transplanted, beta-galactosidase-tagged neural stem cells underwent hematopoietic differentiation. Our results suggest that neural stem cells do undergo extramedullary hematopoiesis, even while no endogenous hematopoietic colonies develop in the spleen. Furthermore, we found that neural stem cells effectively colonized the bone marrow of splectomized recipients. We conclude that the hematopoietic differentiation of neural stem cells is highly dependent on the extramedullary environment. We also conclude that the bone marrow does not provide an environment supportive of hematopoietic differentiation by neural stem cells. 相似文献