全文获取类型
收费全文 | 4725篇 |
免费 | 310篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 188篇 |
妇产科学 | 214篇 |
基础医学 | 603篇 |
口腔科学 | 56篇 |
临床医学 | 390篇 |
内科学 | 1075篇 |
皮肤病学 | 32篇 |
神经病学 | 701篇 |
特种医学 | 231篇 |
外科学 | 349篇 |
综合类 | 20篇 |
一般理论 | 5篇 |
预防医学 | 530篇 |
眼科学 | 40篇 |
药学 | 270篇 |
肿瘤学 | 325篇 |
出版年
2023年 | 17篇 |
2022年 | 43篇 |
2021年 | 72篇 |
2020年 | 47篇 |
2019年 | 77篇 |
2018年 | 127篇 |
2017年 | 105篇 |
2016年 | 102篇 |
2015年 | 114篇 |
2014年 | 121篇 |
2013年 | 217篇 |
2012年 | 305篇 |
2011年 | 282篇 |
2010年 | 146篇 |
2009年 | 161篇 |
2008年 | 265篇 |
2007年 | 252篇 |
2006年 | 245篇 |
2005年 | 257篇 |
2004年 | 218篇 |
2003年 | 225篇 |
2002年 | 155篇 |
2001年 | 144篇 |
2000年 | 140篇 |
1999年 | 104篇 |
1998年 | 44篇 |
1997年 | 41篇 |
1996年 | 41篇 |
1995年 | 40篇 |
1994年 | 28篇 |
1993年 | 41篇 |
1992年 | 88篇 |
1991年 | 75篇 |
1990年 | 75篇 |
1989年 | 79篇 |
1988年 | 76篇 |
1987年 | 60篇 |
1986年 | 53篇 |
1985年 | 60篇 |
1984年 | 45篇 |
1983年 | 27篇 |
1982年 | 20篇 |
1981年 | 18篇 |
1980年 | 14篇 |
1979年 | 26篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1975年 | 25篇 |
1974年 | 15篇 |
排序方式: 共有5042条查询结果,搜索用时 15 毫秒
21.
J Lam R A Neirotti A Nijveld J L Schuller C M Blom-Muilwijk C A Visser 《Journal of the American Society of Echocardiography》1991,4(1):43-50
Transesophageal echocardiography was attempted in 59 pediatric patients with congenital heart disease in the operating room (n = 33) or during heart catheterization or in the intensive care unit (n = 26). Six different commercially available transducers were used with diameters ranging from 7 to 15 mm. Age ranged from 1 day to 16 years, and body weight ranged from 3.7 to 65 kg. Objectives of the study were to determine (1) minimum body weight in which transesophageal echocardiography with various probes is possible, (2) additional diagnostic value, and (3) potential applications. In three cases (one surgical and two nonsurgical) the probe could not be inserted. Minimum body weight was 17 to 20 kg for probes with a diameter of greater than or equal to 13 mm and approximately 12 kg for the 11 mm probes. A 7 mm probe, on the other hand, could be inserted easily in all patients (including a neonate) in whom transesophageal echocardiography was attempted. In 11 of 56 patients, additional diagnostic information was obtained. Thus, transesophageal echocardiography is feasible in the pediatric age group provided that special probes are used in small children. Additional diagnostic information can be obtained, and the technique is of value during cardiac surgery or balloon interventions for evaluation of the efficacy of the procedure and for monitoring ventricular function. 相似文献
22.
Prospect for enzyme therapy in glycogenosis II variants: a study on cultured muscle cells 总被引:4,自引:0,他引:4
A. T. van der Ploeg P. A. Bolhuis R. A. Wolterman J. W. Visser M. C. B. Loonen H. F. M. Busch A. J. J. Reuser 《Journal of neurology》1988,235(7):392-396
Summary Impairment of skeletal muscle function is the common feature of distinct clinical forms of glycogenosis type II. In the present study, muscle cultures from different patients were used to investigate the cause of clinical heterogeneity and the feasibility of enzyme replacement therapy. The activity of acid -glucosidase appears to be the primary factor in determining the extent of lysosomal glycogen storage in muscle, and thereby the clinical severity of the disease. Neutral -glucosidases do not seem influencial. Correction of the enzymatic defect was achieved in skeletal muscle cultures from patients by administration of a high-uptake form of acid -glucosidase, purified from human urine. The enzyme reaches the lysosomes, including the glycogen storage vacuoles, and the lysosomal glycogen content is reduced to control level. In normal muscle cells 20% of the total cellular glycogen pool is segregated in lysosomal compartments. This percentage is higher than in fibroblasts, which may partly explain why muscles are more prone to store glycogen. The relevance of this study for enzyme therapy is discussed. 相似文献
23.
T. C. Jansen H. N. Lafeber H. K. A. Visser G. Kwant B. Oeseburg W. G. Zijlstra 《Medical & biological engineering & computing》1978,16(3):274-277
A membrane-covered catheter-tip oxygen-electrode system is described, which gives a linear response in the Po2 range of 0–350 mm Hg. The system is highly stable, free from drift and mechanically safe for application in man. This is accomplished by using a screw cap for fastening the membrane holder, thus preventing the loss of parts and making the electrolyte chamber really fluidtight. Insulation of the platinum wire with glass precludes the possibility of fluid-bridge contact with the silver anode beyond the measuring site at the tip. 相似文献
24.
25.
van der Palen J Monninkhof E van der Valk P Visser A 《Patient education and counseling》2004,52(3):221-223
This special issue of Patient Education and Counseling is long overdue. During most of the last two decades asthma, and notably asthma self-management has been in the spotlight, while COPD has had to endure a nihilistic approach. The first sign that interest was shifting to the treatment of COPD came from a few large randomized trials on the use of inhaled corticosteroids (ICS) in COPD. Although these studies demonstrated a moderate effect of ICS in COPD, it has become clear that true improvements in the management of this chronic disease will have to come from behavioral interventions. This special issue of Patient Education and Counseling is dedicated solely to the non-pharmaceutical management of COPD. It addresses many issues related to behavioral therapy, such as smoking cessation, exercise training, nutritional aspects, and self-management programs, including action plans to self-treat exacerbations. With the availability of all the treatment and management options, described in this special issue, a nihilistic attitude toward the patient with COPD is no longer justified. 相似文献
26.
J. R. Brunsting K. R. Visser W. G. Zijlstra 《Pflügers Archiv : European journal of physiology》1975,356(3):193-208
A technique is described for perfusion of the entire coronary arterial system of the dog heart in situ and for drainage of the coronary sinus blood. Both coronary arteries are cannulated without ligation of major ventricular branches and disconnected from the aorta. The cannulas are connected to an extracorporeal system allowing perfusion under controlled pressure, without ill effects to either the heart or the blood. The arterial perfusion system is fed from the femoral arteries of the dog. The coronary sinus is cannulated for draining the blood to a venous reservoir against a controlled pressure. From the reservoir the blood is pumped into a femoral vein. Thus a preparation is obtained in which the interdependency of coronary circulation and performance of the heart has been discontinued. Under careful monitoring of pressures and flows, and of blood temperature, blood gases and plasma electrolytes, the preparation has been kept in excellent condition for up to 7 hrs. 相似文献
27.
This study attempted to determine whether a prior period of “stress” would elicit the sensitization reaction of the skin to topically applied chemical agents. A subthreshold concentration of 1-chloro-, 2-4, dinitrobenzene (DNCB) was applied to the skin of 40 guinea-pigs, 20 of which had been subjected to repetitive electrical shocks throughout the previous 15 minutes. They were examined 24 hours later, and were retested with DNCB at another site after 9 days for signs of delayed sensitization. The stressed animals exhibited a more severe contact-reaction (p <. 01) after the induction test and also after the delayed test. 相似文献
28.
Measurement of antibody-mediated binding of human polymorphonuclear leukocytes to HSV-1 infected anchorage fibroblasts 总被引:2,自引:0,他引:2
K P Van Kessel H J Van Kats-Renaud J A Van Strijp M R Visser J Verhoef 《Journal of immunological methods》1986,88(1):101-107
A method for the quantitation of effector cell binding to anchorage fibroblast monolayers infected with HSV-1 is described. Human peripheral blood polymorphonuclear leukocytes (PMN) as effector cells were labeled with chromium-51. Fetal human lung fibroblasts were grown to confluency in microtiter plates, infected with HSV-1 and loaded with anti-HSV antibody. The amount of radiolabeled PMN adhering to the monolayer was determined after appropriate incubation and washings. The effector binding assay was shown to be dependent on specific anti-HSV antibodies, antibody concentration, HSV viral expression, and inoculation time. This assay system is especially useful for the evaluation of effector to target cell conjugate formation when applied to anchorage target cells. 相似文献
29.
Keratinocyte-derived growth factors play a role in the formation of hypertrophic scars 总被引:17,自引:0,他引:17
Niessen FB Andriessen MP Schalkwijk J Visser L Timens W 《The Journal of pathology》2001,194(2):207-216
In predisposed individuals, wound healing can lead to hypertrophic scar or keloid formation, characterized by an overabundant extracellular matrix. It has recently been shown that hypertrophic scars are accompanied by abnormal keratinocyte differentiation and proliferation, and significantly increased acanthosis, compared with normal scars. This study addressed the question of whether the development of normal and hypertrophic scars is regulated by differences in the growth factor profiles of both the epidermis and the dermis. The presence of interleukin-1alpha (IL-1alpha), IL-1beta, tumour necrosis factor-alpha (TNF-alpha), platelet-derived growth factor (PDGF), transforming growth factor-beta1 (TGF-beta1), and basic fibroblast growth factor (bFGF) was investigated in biopsies taken from breast reduction scars at 3 and 12 months following surgery. The samples were analysed by immunohistological methods and categorized as scars that remained hypertrophic (HH), became normal (HN) or remained normal after 12 months (NN). The epidermal expression of IL-1alpha was significantly increased in NN scars compared with HN and HH scars 3 and 12 months following operation, whereas the dermal expression showed no difference. PDGF was significantly increased in the dermis of normal scars after 3 months and in both the epidermis and the dermis of hypertrophic scars after 12 months. IL-1beta, TNF-alpha, TGF-beta and bFGF showed no differences. It is hypothesized that impaired production of keratinocyte-derived growth factors, such as IL-1alpha, leads to a decrease in the catabolism of the dermal matrix, whereas augmented epidermal PDGF production leads to increased formation of the dermal matrix in hypertrophic scars. These observations support the possibility that the epidermis is involved in preventing the formation of hypertrophic scars. 相似文献
30.
The pulmonary CO diffusing capacity (d
l, co) was determined according to Filley et al., by these authors' method and according to Bates et al. in 24 patients with unequal ventilation without severe diffusion disturbances. Under the influence of the unequal ventilation, the Filley method yielded too high D values, while the values according to Bates were too low. The D values obtained by the authors' method were in between the above two extremes.In patients with unequal ventilation, the d value calculated by one of these methods affords little information as to the presence or absence of a diffusion disturbance, and no information on the extent of this diffusion disturbance. Only if D(F) is much too low is there a possibility of a disturbance in diffusion. A normal D(B) or D(K) indicates the probability of absence of a diffusion disturbance. 相似文献