全文获取类型
收费全文 | 1823篇 |
免费 | 111篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 86篇 |
妇产科学 | 38篇 |
基础医学 | 243篇 |
口腔科学 | 52篇 |
临床医学 | 161篇 |
内科学 | 375篇 |
皮肤病学 | 29篇 |
神经病学 | 66篇 |
特种医学 | 436篇 |
外科学 | 111篇 |
综合类 | 44篇 |
预防医学 | 160篇 |
眼科学 | 6篇 |
药学 | 52篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 60篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 13篇 |
2018年 | 10篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 20篇 |
2014年 | 38篇 |
2013年 | 56篇 |
2012年 | 37篇 |
2011年 | 41篇 |
2010年 | 42篇 |
2009年 | 66篇 |
2008年 | 47篇 |
2007年 | 80篇 |
2006年 | 53篇 |
2005年 | 47篇 |
2004年 | 44篇 |
2003年 | 35篇 |
2002年 | 28篇 |
2001年 | 30篇 |
2000年 | 29篇 |
1999年 | 33篇 |
1998年 | 83篇 |
1997年 | 86篇 |
1996年 | 85篇 |
1995年 | 70篇 |
1994年 | 43篇 |
1993年 | 64篇 |
1992年 | 15篇 |
1991年 | 26篇 |
1990年 | 37篇 |
1989年 | 67篇 |
1988年 | 46篇 |
1987年 | 56篇 |
1986年 | 61篇 |
1985年 | 78篇 |
1984年 | 43篇 |
1983年 | 32篇 |
1982年 | 29篇 |
1981年 | 34篇 |
1980年 | 39篇 |
1979年 | 11篇 |
1978年 | 20篇 |
1977年 | 26篇 |
1976年 | 21篇 |
1975年 | 23篇 |
1970年 | 5篇 |
排序方式: 共有1938条查询结果,搜索用时 12 毫秒
81.
Role of point A in the era of computerized dosimetry 总被引:1,自引:0,他引:1
82.
In 44 patients with one or more calculi in the upper two-thirds of the ureter, single-stage percutaneous nephrolithotomy was performed through a middle or upper calyceal nephrostomy after cystoscopic placement of an occlusion balloon catheter distal to the calculus; in 42, the procedure was successful. The occlusion balloon catheter permitted retrograde opacification of all systems for enhanced renal puncture. In the last 30 patients an attempt was made either to push the calculus upward mechanically or to flush it upward into the renal pelvis with carbon dioxide or dilute contrast material. This was successful in 24 of these patients. Prior overnight occlusion of the ureter by means of ureteral dilatation further facilitates dislodgment of the calculus, which was successful in 12 of 13 patients. 相似文献
83.
Marrow harvesting from normal donors 总被引:4,自引:2,他引:4
Buckner CD; Clift RA; Sanders JE; Stewart P; Bensinger WI; Doney KC; Sullivan KM; Witherspoon RP; Deeg HJ; Appelbaum FR 《Blood》1984,64(3):630-634
The experience at a single institution in harvesting marrow for allogeneic transplantation on 1,270 occasions from 1,160 normal donors is presented in detail, together with an analysis of all the donor complications. Four donors were less than 2 years old, and the youngest was 6 1/2 months. No special difficulties were encountered with these young donors. Hospitalization time was three days or less for 99% of the procedures. Six donors had life-threatening complications; three of a cardiopulmonary and two of an infectious nature, and one cerebrovascular embolic episode. Significant operative site morbidity, usually transient neuropathies, occurred in ten procedures. Ten percent of the donations were associated with transient postoperative fever of unknown origin. Increasing donor age was associated with a reduction of the cellularity of the marrow harvest. The use of stored autologous blood permitted the avoidance of blood bank transfusion in 81% of males, 69% of females, and 50% of children. It was concluded that the procedure was associated with a very low risk of complication, but that the involvement of normal donors in such an operation justifies stringent monitoring. 相似文献
84.
The effect of PGI2 and theophylline on the response of platelets subjected to shear stress 总被引:2,自引:0,他引:2
A specially designed rotational viscometer was used to investigate the effects of the antiplatelet agent PGI2 in combination with theophylline on the response of human platelets subjected to shear stress. Samples of citrated platelet-rich plasma (PRP) were exposed to shear stress in the viscometer for a period of 5 min at 23 degrees C. The levels of stress studied ranged from 50 to 300 dynes/sq cm. Pretreatment of the platelets with 0.01 microM PGI2 and 500 microM theophylline before exposure to shear stress caused a large reduction in shear-induced platelet aggregation. However, it was also observed that the PGI2-- theophylline pretreatment concomitantly caused a large increase in shear-induced platelet lysis and serotonin release at stress levels equal to or greater than 150 dynes/sq cm. This observed increase in platelet fragility may have important implications for clinical applications of PGI2. The results are discussed and compared to those obtained in prior work in which platelets were pretreated with acetylsalicylic acid or with PGE1. 相似文献
85.
Membrane fluidity changes accompanying phagocytosis in normal and in chronic granulomatous disease polymorphonuclear leukocytes 总被引:2,自引:0,他引:2
We have studied membrane fluidity changes in polymorphonuclear leukocytes (PMN) during phagocytosis. Membrane fluidity was assessed by electron spin resonance (ESR) using a nitroxide-substituted stearic acid analog (5DS) as a spin probe. PMN from normal subjects and from 3 CGD patients (2 males, 1 female) were incubated in Kreb's Ringers phosphate with or without opsonized zymosan. ESR spectra were obtained and the order parameter (S), which is inversely related to membrane fluidity, was calculated. Without zymosan addition, S for normal (0.638) and for CGD (0.635) were not significantly different (p less than 0.35). The S values indicate that under resting conditions the molecular environment of the CGD membrane is similar to that of normal PMN membranes. However, with addition of opsonized zymosan, the normal, but not the CGD, PMN showed a significant increase (CGD, S = 0.638; normal, S = 0.647; p less than 0.001). This change in S for the normals is consistent with a more restricted movement of 5DS. Treatment of normal PMN with a mixture of scavengers specific for H2O2 (catalase, 1600 U/ml), O2-.(superoxide dismutase, 100 micrograms/ml), and for HO., (sodium benzoate, 1mM) during zymosan stimulation gave S values similar to those of resting cells. Catalase alone also lowered S value, suggesting that H2O2 was instrumental in causing the initial S value increase. This idea was supported by studies in which CGD cells were incubated with zymosan in the presence of glucose oxidase, an enzyme that catalyzes glucose oxidation resulting in the direct reduction of molecular oxygen to H2O2. Our results indicate that reduced O2 by- products, particularly H2O2, can cause altered biophysical properties of PMN membrane during phagocytosis. 相似文献
86.
High-dose etoposide and cyclophosphamide without bone marrow transplantation for resistant hematologic malignancy 总被引:2,自引:1,他引:2
Brown RA; Herzig RH; Wolff SN; Frei-Lahr D; Pineiro L; Bolwell BJ; Lowder JN; Harden EA; Hande KR; Herzig GP 《Blood》1990,76(3):473-479
Seventy-five patients with resistant acute leukemia or lymphoma received high-dose cyclophosphamide and etoposide to explore the activity of this combination in resistant hematologic malignancies, and to determine the maximum doses of these drugs that can be combined without bone marrow transplantation. Etoposide was administered over 29 to 69 hours by continuous infusion corresponding to total doses of 1.8 g/m2 to 4.8 g/m2. Cyclophosphamide, 50 mg/kg/d, was administered on 3 or 4 consecutive days total 150 to 200 mg/kg ideal body weight). At all dose levels myelosuppression was severe but reversible. Mucosal toxicity was dose-limiting with the maximum tolerated dose level combining etoposide 4.2 g/m2 with cyclophosphamide 200 mg/kg. Continuous etoposide infusion produced stable plasma levels that were lower than would be achieved after administration by short intravenous infusion, and this could explain our ability to escalate etoposide above the previously reported maximum tolerated dose. There were 28 complete (35%) and 12 partial (16%) responses. Median duration of complete response (CR) was 3.5 months (range 1.1 to 20+). Seventeen of 40 patients (42%) with acute myelogenous leukemia (AML) achieved CR, including 6 of 20 (30%) with high-dose cytosine arabinoside resistance. We conclude that bone marrow transplantation is not required after maximum tolerated doses of etoposide and cyclophosphamide. This regimen is active in resistant hematologic neoplasms, and the occurrence of CR in patients with high-dose cytosine arabinoside-resistant AML indicates a lack of complete cross-resistance between these regimens. 相似文献
87.
Helen L. Grierson James Skare Joseph Church Teresa Silberman Jack R Davis Nathan Kobrinsky Rebert McGregor Sara Israels James McCarty Lucy G. Andrews Timothy Blecha Steve Erdman Angela Obringer David Scharnhorst David T. Purtilo 《American journal of medical genetics. Part A》1993,47(4):458-463
The Epstein-Barr virus (EBV)-induced diseases of males with X-linked lymphoproliferative disease (XLP) include fatal infectious mononucleosis (IM), non-Hodgkin lymphoma (ML), agammaglobulinemia, and aplastic anemia. These phenotypes also occur as sporadic cases in families, and EBV seronegative males in these families must be considered at risk for XLP until they seroconvert normally to EBV. Given that 50% of males inheriting the defective XLP gene die following primary EBV infection, it is vital that they be identified pre-EBV infection. Here we report result using molecular genetic techniques to provide information as to the relative risks of EBV negative males and potential carrier females in ten families wherein a single male had died of IM. © 1993 Wiley-Liss, Inc. 相似文献
88.
89.
90.
RA Parker J Himmelfarb N Tolkoff-Rubin P Chandran RL Wingard RM Hakim 《American journal of kidney diseases》1998,32(3):432-443
Despite several decades of clinical experience, the mortality rate for patients with acute renal failure (ARF) requiring dialysis remains high, and the evaluation of the patients prognosis has been difficult. To date, the Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring system has been used more frequently for prediction in studies of ARF than any other scoring system, but has not been prospectively validated in controlled multicenter studies of this entity. In a multicenter, prospective, controlled trial evaluating the use of biocompatible hemodialysis membranes (BCMs) in patients with ARF, we evaluated the extent to which the APACHE II scoring system, based on the physiological variables in the 24 hours before the onset of dialysis and the presence or absence of oliguria, is predictive of outcome. Analysis of survival and recovery of renal function for the 153 patients treated in this study show that APACHE II scores are predictive both of survival and recovery of renal function, whether analyzed separately by type of dialysis membrane used (BCM or bioincompatible [BICM]) or for both groups combined (all P < 0.01). There was no evidence of a significant center effect or interaction of APACHE II score with dialysis membrane in our study. After adjusting for the APACHE II score, there was a positive effect of the BCM on both probability of survival (P < 0.05) and recovery of renal function (P < 0.01). In patients dialyzed with BCMs, oliguria at onset of dialysis had an adverse effect on both survival and recovery of renal function (both P < 0.01). Receiver operator curves (ROCs) using APACHE II score and the use of BCMs in nonoliguric patients yielded a statistically significant improvement versus the use of APACHE II score alone in the area under the curve (AUC) for survival (0.747 to 0.801; P < 0.05) and recovery of renal function (0.712 to 0.775; P < 0.05). We conclude that the use of the APACHE II score determined at the time of initiation of dialysis for patients with ARF is a statistically significant predictor of patient survival and recovery of renal function. The use of the APACHE II score measured at the time of dialysis initiation, especially when modified by the presence or absence of oliguria, should help in predicting outcome when evaluating interventions for patients with ARF. 相似文献