全文获取类型
收费全文 | 18277篇 |
免费 | 1691篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 503篇 |
妇产科学 | 325篇 |
基础医学 | 2705篇 |
口腔科学 | 371篇 |
临床医学 | 2154篇 |
内科学 | 3839篇 |
皮肤病学 | 435篇 |
神经病学 | 1436篇 |
特种医学 | 543篇 |
外科学 | 3061篇 |
综合类 | 451篇 |
一般理论 | 10篇 |
预防医学 | 1577篇 |
眼科学 | 251篇 |
药学 | 1274篇 |
中国医学 | 11篇 |
肿瘤学 | 919篇 |
出版年
2021年 | 220篇 |
2020年 | 167篇 |
2019年 | 259篇 |
2018年 | 243篇 |
2017年 | 234篇 |
2016年 | 251篇 |
2015年 | 267篇 |
2014年 | 383篇 |
2013年 | 536篇 |
2012年 | 871篇 |
2011年 | 818篇 |
2010年 | 440篇 |
2009年 | 447篇 |
2008年 | 755篇 |
2007年 | 816篇 |
2006年 | 805篇 |
2005年 | 807篇 |
2004年 | 754篇 |
2003年 | 719篇 |
2002年 | 660篇 |
2001年 | 561篇 |
2000年 | 666篇 |
1999年 | 536篇 |
1998年 | 257篇 |
1997年 | 227篇 |
1996年 | 218篇 |
1995年 | 173篇 |
1994年 | 175篇 |
1993年 | 181篇 |
1992年 | 495篇 |
1991年 | 471篇 |
1990年 | 415篇 |
1989年 | 413篇 |
1988年 | 406篇 |
1987年 | 372篇 |
1986年 | 365篇 |
1985年 | 331篇 |
1984年 | 321篇 |
1983年 | 226篇 |
1982年 | 147篇 |
1981年 | 148篇 |
1980年 | 137篇 |
1979年 | 261篇 |
1978年 | 161篇 |
1977年 | 126篇 |
1976年 | 138篇 |
1974年 | 166篇 |
1973年 | 163篇 |
1972年 | 157篇 |
1971年 | 122篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
V. M. Mann J. M. Cooper S. E. Daniel K. Srai P. Jenner C. D. Marsden A. H. V. Schapira 《Annals of neurology》1994,36(6):876-881
Elevated iron levels, enhanced oxidative damage, and complex I deficiency have been identified in the substantia nigra of Parkinson's disease patients. To understand the interrelationship of these abnormalities, we analyzed iron levels, ferritin levels, and complex I activity in the substantia nigra of patients with Parkinson's disease. Total iron levels were increased significantly, ferritin levels were unchanged, and complex I activities were decreased significantly in the substantia nigra samples. The failure of ferritin levels to increase with elevated iron concentrations suggests that the amount of reactive iron may increase in the substantia nigra of Parkinson's disease patients. There was no correlation between the iron levels and complex I activity or the iron-ferritin ratio and complex I activity in the substantia nigra samples. 相似文献
82.
83.
84.
Edward D Moloney Jim J Egan Peter Kelly Alfred E Wood Leslie T Cooper 《The Journal of heart and lung transplantation》2005,24(8):1103-1110
Myocarditis is a major cause of end-stage heart failure and is responsible for up to 10% of cases of idiopathic dilated cardiomyopathy (IDC). Worldwide, approximately 45% of all heart transplants are performed for IDC and up to 8% for myocarditis. Early reports suggested that survival after transplantation for myocarditis was poor and patients had an increased risk of rejection. More recently, larger case series suggest that overall survival after transplantation for myocarditis is similar to survival after transplantation for other causes. However, certain disorders, including cardiac sarcoidosis and giant cell myocarditis (GCM), require heightened surveillance for post-transplantation disease recurrence. We present the case of a 42-year-old man with recurrence of GCM 8 years after transplantation and review the literature on the role of cardiac transplantation for patients with myocarditis. 相似文献
85.
Martin C. Robson MD ; Diane M. Cooper PhD RN ; Rummana Aslam MD ; Lisa J. Gould MD PhD ; Keith G. Harding MBChB MRCGP FRCS ; David J. Margolis MD MSCE PhD ; Diane E. Ochs RN ; Thomas E. Serena MD ; Robert J. Snyder DPM ; David L. Steed MD ; David R. Thomas MD ; Laurel Wiersema-Bryant RN BC ANP 《Wound repair and regeneration》2008,16(2):147-150
86.
87.
Effects of insulin on diacylglycerol-protein kinase C signaling in rat diaphragm and soleus muscles and relationship to glucose transport 总被引:2,自引:0,他引:2
Insulin was found to provoke rapid increases in diacylglycerol (DAG) content and [3H]glycerol incorporation into DAG and other lipids during incubations of rat hemidiaphragms and soleus muscles. Insulin also rapidly increased phosphatidic acid and total glycerolipid labeling by [3H]glycerol, suggesting that insulin increases DAG production at least partly through stimulation of the de novo pathway. Increased DAG production may activate protein kinase C (PKC) as reported previously in the rat diaphragm. We also observed apparent insulin-induced translocation of PKC from cytosol to membrane in the rat soleus muscle. The importance of insulin-induced increases in DAG-PKC signaling in the stimulation of glucose transport in rat diaphragm and soleus muscles was suggested by 1) PKC activators phorbol esters and phospholipase C stimulation of [3H]-2-deoxyglucose (DOG) uptake and 2) PKC inhibitors staurosporine and polymixin B inhibition of insulin effects on [3H]-2-DOG uptake. Although phorbol ester was much less effective than insulin in the diaphragm, phospholipase C provoked increases in [3H]-2-DOG uptake that equaled or exceeded those of insulin. In the soleus muscle, phorbol ester, like phospholipase C, was only slightly but not significantly less effective than insulin. Similar variability in effectiveness of phorbol ester has also been noted previously in rat adipocytes (weak) and BC3H1 myocytes (strong), whereas DAG, added exogenously or generated by phospholipase C treatment, stimulates glucose transport to a degree that is quantitatively more comparable to that of insulin in each of the four tissues. Differences in effectiveness of phorbol ester and DAG could not be readily explained by postulating that the latter acts independently of PKC, because DAG provoked the apparent translocation of the enzyme from cytosol to membranes in rat adipocytes, and effects of DAG on [3H]-2-DOG uptake were blocked by inhibitors of PKC in both rat adipocytes and BC3H1 myocytes. Collectively, our findings provide further support for the hypothesis that insulin increases DAG production and PKC activity, and these processes are important in the stimulation of glucose transport in rat skeletal muscle and other tissues. 相似文献
88.
D. J. King M. Blomqvist S. J. Cooper M. M. Doherty M. J. Mitchell R. C. Montgomery 《Psychopharmacology》1992,107(2-3):175-179
Sixty-two DSM III chronic schizophrenic inpatients were selected for a double-blind, placebo controlled, multi-centre, relapse prevention study of remoxipride, a selective dopamine (D2)-receptor antagonist. After a 1 month placebo washout, 23 patients had relapsed and were withdrawn. Of the remaining patients 19 were randomised to remoxipride (150–300 mg daily) and 20 to placebo. Their median age was 58 years, 26 were male, and the median duration of illness was 33 years. After 24 weeks a further total of 8 remoxipride and 17 placebo patients had been withdrawn. Excluding three patients withdrawn for reasons other than relapse, the comparative relapse rates were 37% and 75%, respectively (P=0.015). Efficacy analyses using clinical global impression (P=0.04) and change in BPRS scores (P=0.016) were in favour of remoxipride. Extrapyramidal symptoms were minimal in both groups. Treatment emergent adverse events were similar in the two groups. Remoxipride is therefore of potential value as a safe drug which is both effective and well tolerated in the long term management of chronic schizophrenic patients. 相似文献
89.
James Gordon Maria Felice Ghilardi Scott E. Cooper Claude Ghez 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1994,99(1):97-111
This study examined the variability in movement end points in a task in which human subjects reached to targets in different locations on a horizontal surface. The primary purpose was to determine whether patterns in the variable errors would reveal the nature and origin of the coordinate system in which the movements were planned. Six subjects moved a hand-held cursor on a digitizing tablet. Target and cursor positions were displayed on a computer screen, and vision of the hand and arm was blocked. The screen cursor was blanked during movement to prevent visual corrections. The paths of the movements were straight and thus directions were largely specified at the onset of movement. The velocity profiles were bell-shaped, and peak velocities and accelerations were scaled to target distance, implying that movement extent was also programmed in advance of the movement. The spatial distributions of movement end points were elliptical in shape. The major axes of these ellipses were systematically oriented in the direction of hand movement with respect to its initial position. This was true for both fast and slow movements, as well as for pointing movements involving rotations of the wrist joint. Using principal components analysis to compute the axes of these ellipses, we found that the eccentricity of the elliptical dispersions was uniformly greater for small than for large movements: variability along the axis of movement, representing extent variability, increased markedly but nonlinearly with distance. Variability perpendicular to the direction of movement, which results from directional errors, was generally smaller than extent variability, but it increased in proportion to the extent of the movement. Therefore, directional variability, in angular terms, was constant and independent of distance. Because the patterns of variability were similar for both slow and fast movements, as well as for movements involving different joints, we conclude that they result largely from errors in the planning process. We also argue that they cannot be simply explained as consequences of the inertial properties of the limb. Rather they provide evidence for an organizing mechanism that moves the limb along a straight path. We further conclude that reaching movements are planned in a hand-centered coordinate system, with direction and extent of hand movement as the planned parameters. Since the factors which influence directional variability are independent of those that influence extent errors, we propose that these two variables can be separately specified by the brain. 相似文献
90.
M Kaplan HJ Vreman C Hammerman C Leiter B Rudensky MG MacDonald DK Stevenson 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(4):455-457
The incidence (%) of hyperbilirubinemia (serum bilirubin ≥257 μmol/l) was similar in neonates with a combination of ABO incompatibility and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (45%), with ABO incompatibility (54%) or G-6-PD deficiency (37%), alone (ns). Carboxyhemoglobin values, corrected for inspired CO, were similarly elevated in all three groups (0.87 ± 0.32%, 0.82 ± 0.29%, 0.76 ± 0.18%, respectively, ns), but correlated with bilirubin only in those with ABO incompatibility alone. ABO-incompatible/G-6-PD-deficient neonates, compared with those with either condition alone, are not at increased risk for hemolysis or hyperbilirubinemia. 相似文献