全文获取类型
收费全文 | 46065篇 |
免费 | 4839篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 438篇 |
儿科学 | 1216篇 |
妇产科学 | 1096篇 |
基础医学 | 6911篇 |
口腔科学 | 1067篇 |
临床医学 | 5678篇 |
内科学 | 8461篇 |
皮肤病学 | 546篇 |
神经病学 | 4456篇 |
特种医学 | 1794篇 |
外国民族医学 | 57篇 |
外科学 | 5921篇 |
综合类 | 985篇 |
一般理论 | 43篇 |
预防医学 | 5149篇 |
眼科学 | 1128篇 |
药学 | 3442篇 |
中国医学 | 24篇 |
肿瘤学 | 2603篇 |
出版年
2021年 | 656篇 |
2020年 | 408篇 |
2019年 | 645篇 |
2018年 | 716篇 |
2017年 | 553篇 |
2016年 | 605篇 |
2015年 | 644篇 |
2014年 | 961篇 |
2013年 | 1517篇 |
2012年 | 2025篇 |
2011年 | 2068篇 |
2010年 | 1234篇 |
2009年 | 1074篇 |
2008年 | 1971篇 |
2007年 | 1969篇 |
2006年 | 1998篇 |
2005年 | 1911篇 |
2004年 | 1947篇 |
2003年 | 1715篇 |
2002年 | 1691篇 |
2001年 | 1484篇 |
2000年 | 1609篇 |
1999年 | 1366篇 |
1998年 | 592篇 |
1997年 | 518篇 |
1996年 | 469篇 |
1995年 | 475篇 |
1994年 | 436篇 |
1993年 | 401篇 |
1992年 | 1071篇 |
1991年 | 1114篇 |
1990年 | 1024篇 |
1989年 | 1008篇 |
1988年 | 1011篇 |
1987年 | 880篇 |
1986年 | 872篇 |
1985年 | 842篇 |
1984年 | 701篇 |
1983年 | 583篇 |
1982年 | 383篇 |
1981年 | 358篇 |
1980年 | 346篇 |
1979年 | 661篇 |
1978年 | 516篇 |
1977年 | 439篇 |
1976年 | 414篇 |
1975年 | 384篇 |
1974年 | 438篇 |
1973年 | 437篇 |
1972年 | 377篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The effect of restraint on the activation of macrophages was evaluated based on the induction of I-A expression following injection of viable Mycobacterium bovis (strain BCG) or treatment in vitro with recombinant interferon-gamma (rIFN-gamma). We found that restraint suppressed the induction of I-A expression when applied just prior to or at the same time as the injection of the microorganisms but had no effect if applied after the injection of the Mycobacteria. The effect of stress was attenuated by increasing the number of microorganisms or by incubating macrophages from stressed mice with higher doses of rIFN-gamma. The suppressive effect of restraint does not appear to be associated with uptake, processing or presentation of antigen but rather to an alteration in the response of the macrophages to rIFN-gamma. 相似文献
82.
Effects of inotropes on human leucocyte numbers, neutrophil function and lymphocyte subtypes 总被引:1,自引:1,他引:0
Burns A. M.; Keogan M.; Donaldson M.; Brown D. L.; Park G. R. 《British journal of anaesthesia》1997,78(5):530-535
We have investigated the effects of inotropes with different adrenergic
receptor specificity on differential white cell count, lymphocyte subtypes
and neutrophil function in healthy volunteers. Six healthy, male volunteers
were enrolled into this randomized, placebo-controlled pilot study. Each
volunteer was studied on four separate occasions during a 2-h infusion of
various agents, and for 2 h after stopping the infusion. The agents
investigated were adrenaline 0.1 microgram kg-1 min-1, dobutamine 5
micrograms kg-1 min-1, dopexamine 2 micrograms kg-1 min-1 and 5% glucose
0.5 ml kg-1 h-1. Venous blood was sampled at 0, 30, 120 and 240 min.
Haemodynamic monitoring was continued throughout the study. Full blood
count, white cell differential count and enumeration of lymphocyte subtypes
were performed. Neutrophil function tests included chemoluminescence, and
assessment of neutrophil chemotaxis, phagocytosis and adhesion. The
Wilcoxon signed rank test was used to compare differences between placebo
and active drugs at each time compared with baseline. There was a
significant increase in white cell count, lymphocyte count and neutrophil
count with adrenaline, and a small but significant decrease in these
variables with dobutamine and dopexamine. These changes were also apparent
for absolute CD3+, CD4+ and CD8+ lymphocyte counts. Neutrophil respiratory
burst in response to f-methionyl-leucyl-phenylalanine increased
significantly only with adrenaline at 30 min (P = 0.046). There were no
other significant changes in tests of neutrophil function. Infusion of
inotropes was associated with changes in white cell numbers, lymphocyte
subtypes and neutrophil respiratory burst. In healthy volunteers,
adrenaline had effects different from those of dobutamine and dopexamine.
The clinical relevance of such effects requires further investigation in
critically ill patients.
相似文献
83.
T M Kim H R Brown S H Lee C V Powell P Bethune N L Goller H T Tran J S Mackay 《Modern pathology》1992,5(3):348-352
A 9-yr-old girl developed delayed acute measles inclusion body encephalitis, which was different from subacute sclerosing panencephalitis (SSPE) in clinical course. Measles virus was demonstrated by electron microscopy, immunohistochemistry, and in situ hybridization. Contrary to the most previous reports, matrix (M) protein was present in the brain, cerebrospinal fluid, and serum and was demonstrated by Western blot analysis and in situ hybridization. The hybridization was performed by a nonradioactive digoxigenin method. 相似文献
84.
85.
An overview of renal pathology in insulin-dependent diabetes mellitus in relationship to altered glomerular hemodynamics. 总被引:2,自引:0,他引:2
Clinical diabetic nephropathy in man is the consequence of the development of a specific constellation of glomerular, tubular, vascular, and interstitial structural abnormalities accompanied by highly characteristic immunohistochemical alterations that, together, are unique to diabetes. Because changes resembling the specific pathology of diabetes do not develop in patients with conditions that lead to long-standing glomerular hyperfunction (such as unilateral nephrectomy), it is unlikely that glomerular hemodynamic abnormalities per se can be the cause of diabetic nephropathy. Whether hemodynamic abnormalities represent a risk factor that, in the presence of the diabetic state, can accelerate the rate of development of the basic lesions of diabetic nephropathy is currently unclear. However, there is considerable evidence that when the renal lesions of diabetes are far advanced, factors such as systemic hypertension can determine the rate of renal functional deterioration in diabetes as in other disorders. Although the diabetic rat may be a useful model for the study of aspects of the pathogenesis of diabetic nephropathy, much confusion has resulted from the inclusion of focal segmental glomerular sclerosis as a diabetic lesion. Similarly, the acceptance of all increases in urinary protein excretions in this model as resulting from or reflecting of diabetic nephropathology can be misleading. It is concluded that treatment aimed at manipulating renal hemodynamics in diabetic patients without evidence of renal disease should remain in the realm of clinical research. 相似文献
86.
87.
Outcomes in patients with interrupted aortic arch and associated anomalies: a 20-year experience. 总被引:6,自引:0,他引:6
John W Brown Mark Ruzmetov Yuji Okada Palaniswamy Vijay Mark D Rodefeld Mark W Turrentine 《European journal of cardio-thoracic surgery》2006,29(5):666-73; discussion 673-4
OBJECTIVE: The surgical results for the repair of interrupted aortic arch (IAA) have evolved in recent years. We report our results for staged repair of this complex congenital malformation. METHODS: Sixty-five patients (mean age, 16.9+/-41.7 days) were diagnosed with IAA and referred for surgical therapy. The surgical management strategy at our institution between 1982 and 2005 has been one-stage complete repair (n=13) or staged repair (n=52) in selected patients. Non-complex patients (group I, n=51) had a ventricular septal defect (87%), aortopulmonary window (8%), and left ventricular outflow tract obstruction (27%). Group II (n=14) were patients with Taussig-Bing double outlet right ventricle (n=6) or truncus arteriosus (n=8). Method of staged repair of IAA was to transect and turn down the left carotid artery and anastomosis it to the descending aorta (n=41) or graft interposition (n=2) combined with a pulmonary artery (PA) banding followed in a few months by delayed ventricular septal defect (VSD) closure and PA de-banding. RESULTS: There were 5 early and 10 late deaths. The actuarial survival including early mortality was 92% at 1 year, 81% at 5 years, and 76% at 10 and 15 years. There was an 81% 15-year survival for children in group I compared with a 54% for children in group II (p<0.001). Risk factors for increased mortality by univariate analysis were as follows: (1) primary aortic anastomosis (p=0.03), (2) presence of complex anomalies (p=0.05), and (3) initial IAA repair performed before 1994 (p=0.05). Actuarial freedom from any type of aortic reoperation or intervention was 86% at 1 year, 69% at 5 years, and 60% at 10 and 15 years. Univariate and multivariate analyses identified no tested variables as risk factors for reoperation. The majority (86%) was in New York Heart Association (NYHA) class I, and 14% remained in NYHA class II. During the postoperative course there were no neurologic deficits, seizures, and growth disturbances in any patient. CONCLUSION: Staged repair of IAA using a left carotid artery turn down can be safely applied in IAA patients with and without other intracardiac anomalies with good results. Use of the left carotid artery for arch reconstruction did not result in any detectable neurological events or growth disturbances later in life. Associated anomalies played an important role in outcomes. The long-term probability for reoperation and/or reintervention remains high regardless of operative technique. 相似文献
88.
89.
90.
E E Muirhead L W Byers B Brooks J A Pitcock P Brown R Dowell 《The American journal of the medical sciences》1987,294(5):384-387
Selachyl alcohol (SA) is a mono-oleyl glyceryl ether. It has certain biologic activities similar to those of the antihypertensive neutral renomedullary lipid (ANRL) derived from the renal papilla and its renomedullary interstitial cells (RIC). These include a vaso-depressor effect following bolus injection and a requirement for hepatic activation for the development of biological activity. In view of this similarity to ANRL, it appeared worthwhile to test the antihypertensive action of SA when given via the GI tract. Accordingly, pure SA was given either by gavage or by tube into the stomach or duodenum of one-kidney, one-clip hypertensive rats (5-10 mg per dose). The role of hepatic activation was demonstrated by comparing the BP response to bolus injection of SA and ANRL with and without the presence of an intact circulation to the liver. Administration of SA via the GI tract resulted in a significant decline in BP without tachycardia or weight loss. In the absence of a circulation to the liver, neither SA nor ANRL was active. SA appears to be an effective antihypertensive agent when given via the GI tract. 相似文献