全文获取类型
收费全文 | 19937篇 |
免费 | 1507篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 212篇 |
儿科学 | 544篇 |
妇产科学 | 551篇 |
基础医学 | 2811篇 |
口腔科学 | 392篇 |
临床医学 | 1766篇 |
内科学 | 3882篇 |
皮肤病学 | 575篇 |
神经病学 | 2073篇 |
特种医学 | 630篇 |
外科学 | 2706篇 |
综合类 | 117篇 |
一般理论 | 8篇 |
预防医学 | 1812篇 |
眼科学 | 289篇 |
药学 | 1589篇 |
中国医学 | 56篇 |
肿瘤学 | 1477篇 |
出版年
2023年 | 115篇 |
2022年 | 134篇 |
2021年 | 306篇 |
2020年 | 277篇 |
2019年 | 367篇 |
2018年 | 434篇 |
2017年 | 374篇 |
2016年 | 388篇 |
2015年 | 436篇 |
2014年 | 528篇 |
2013年 | 971篇 |
2012年 | 1149篇 |
2011年 | 1160篇 |
2010年 | 683篇 |
2009年 | 652篇 |
2008年 | 1078篇 |
2007年 | 1014篇 |
2006年 | 1096篇 |
2005年 | 1012篇 |
2004年 | 978篇 |
2003年 | 899篇 |
2002年 | 849篇 |
2001年 | 417篇 |
2000年 | 386篇 |
1999年 | 397篇 |
1998年 | 251篇 |
1997年 | 199篇 |
1996年 | 201篇 |
1995年 | 218篇 |
1994年 | 186篇 |
1993年 | 177篇 |
1992年 | 275篇 |
1991年 | 306篇 |
1990年 | 260篇 |
1989年 | 285篇 |
1988年 | 254篇 |
1987年 | 233篇 |
1986年 | 211篇 |
1985年 | 240篇 |
1984年 | 218篇 |
1983年 | 160篇 |
1982年 | 167篇 |
1981年 | 140篇 |
1979年 | 131篇 |
1978年 | 112篇 |
1977年 | 129篇 |
1976年 | 91篇 |
1975年 | 93篇 |
1974年 | 94篇 |
1973年 | 97篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Eduardo M. B. Tinoco Ståle P. Lyngstadaas Hans R. Preus Per Gjermo 《Journal of clinical periodontology》1997,24(12):937-944
Abstract Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Aetinobaeillus actinomycetemcomitans (A. actinomycetemcotnitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients’serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the L.JP patients. CAL was measured at 4 different sites around ail present teeth and assessed as a % of teeth with at least 1 site moderately ≥2<5 mm) or severely (≥5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p<0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients. 相似文献
102.
Pulse methotrexate therapy in rheumatoid arthritis. A controlled prospective roentgenographic study 总被引:2,自引:0,他引:2
Study Objective: To assess whether weekly pulse methotrexate therapy alters radiographic progression of joint disease in patients with rheumatoid arthritis. Design: Prospective, controlled study. Hand, wrist and foot roentgenograms obtained before, at the onset of, and during methotrexate treatment were scored for degree of joint-space narrowing and erosions by three rheumatologists using a standard method. Patients: Sequential sample of 24 patients with active definite or classical rheumatoid arthritis and previous unsuccessful treatment; of these, 3 were excluded due to drug ineffectiveness; 2, due to side effects; and 1, due to refusal to take methotrexate. Interventions: Treatment with nonsteroidal anti-inflammatory drugs and prednisone was continued. Methotrexate was given weekly to control clinical evidence of disease in patients. Measurements and Main Results: After having had an average of 30 months of therapy, the 18 patients who continued to receive methotrexate therapy showed significant (p less than 0.05) clinical improvement, as evidenced by their decreased joint counts and joint scores, duration of morning stiffness, pain scales, and sedimentation rates. Despite patients' prolonged clinical improvement, the mean rate of development of erosions and joint-space narrowing during methotrexate therapy was not significantly different from the rate of radiographic progression before methotrexate therapy (0.043 compared with 0.041; p greater than 0.05). Conclusions: Weekly pulse methotrexate is effective for the long-term management of clinical disease activity in patients with refractory rheumatoid arthritis but may not be a disease-modifying agent by roentgenographic criteria. 相似文献
103.
104.
Certain drugs or chemicals may be added to local anesthetic solutions to enhance the tissue spread of the local anesthetic. Perhaps the best known is glucose (dextrose) added to spinal anesthesia solution to make it hyperbaric and to allow the local anesthetic to spread in the cerebrospinal fluid by gravity, as needed. Hyaluronidase addition has been abandoned in almost all other regional anesthetic blocks except ophthalmologic blocks. Hylauronidase is expensive and it is not devoid of side-effects and, therefore, as low concentrations as possible are recommended. Even as low concentration as 3.75 IU/mL of hyaluronidase is able to enhance the spread of the concentrated local anesthetic solution, causing analgesia and akinesia without damage to the eye muscles. Hyaluronidase addition to local anesthetic solutions is used to some extent also in dermatological surgery. The spread of local anesthetics for topical skin analgesia and anesthesia is promoted by influencing the penetrating property physically (eutectic mixture), electrically (iontophoresis), and encapsulating in liposomes. The penetration (spread) of the local anesthetic through the skin is significantly faster with iontophoresis and liposomes in comparison with the eutectic mixture of local anesthetics. 相似文献
105.
Glucose uptake in human adipose tissue 总被引:6,自引:0,他引:6
Per Mrin Marielle Rebuff-Scrive Ulf Smith Per Bjrntorp 《Metabolism: clinical and experimental》1987,36(12):1154-1160
One hundred grams of glucose with 50 microCi U-14C-glucose were given orally to 17 women with widely varying amounts of body fat. Radioactivity and glucose metabolism in vitro were then measured in adipose tissue obtained by needle biopsies in the abdominal and femoral regions after four hours. Radioactivity in triglycerides was then measured in repeated biopsies 1 day, 1 week, and monthly up to 7 months after glucose administration. Glucose label in triglycerides after four hours was higher in abdominal than femoral adipocytes in obese women. It increased slightly during the following week, and then decreased exponentially with a half-life of 12 months in the abdominal region and 19 months in the femoral region. Uptake of glucose carbon in total body fat was estimated from the triglyceride label measured and determinations of body fat mass, and found to be in the order of less than 4% of given glucose. The studies in vitro suggested that much of the glucose taken up in adipose tissue is converted to lactate. If this is the case in vivo, then glucose uptake in adipose tissue might well be of significance for total body glucose homeostasis, particularly in obese subjects, amounting to maximally perhaps one third to one half of the oral glucose given. The majority of this glucose uptake would then, however, leave adipose tissue again as lactate. The shorter half-life of label in abdominal adipocytes is in agreement with findings of increased lipolysis in these adipocytes in vitro. 相似文献
106.
Per Karlsson Lars Farde Christer Halldin Carl-Gunnar Swahn Göran Sedvall Christian Foged Kristian Tage Hansen Birte Skrumsager 《Psychopharmacology》1993,113(2):149-156
The benzazepines NNC 687 and NNC 756 have in animal studies been described as selective D1-dopamine receptor antagonists. Both compounds have been labeled with11C for examination by positron emission tomography (PET). In the present study central receptor binding was studied in monkeys and healthy men. After IV injection of both radioligands in Cynomolgus monkeys radioactivity accumulated markedly in the striatum, a region with a high density of D1-dopamine receptors. This striatal uptake was displaced by high doses of the selective D1-antagonist SCH 23390 (2 mg/kg) but not by the 5HT2-antagonist ketanserin (1.5 mg/kg) or the selective D2-antagonist raclopride (3 mg/kg). The cortical uptake after injection of [11C]NNC 687 was not reduced in displacement experiments with ketanserin. The cortical uptake of [11C]NNC 756 was reduced in displacement and protection experiments with ketanserin by 24–28% (1.5 mg/kg), whereas no reduction could be demonstrated on striatal uptake. In healthy males both compounds accumulated markedly in the striatum. For [11C]NNC 687 the ratio of radioactivity in the putamen to cerebellum was about 1.5. For [11C]NNC 756 the ratio was about 5. This ratio of 5 for [11C]NNC 756 is the highest obtained so far for PET radioligands for the D1-dopamine receptor. 相似文献
107.
108.
109.
P.H. Andersen H. Vestergaard S. Lund P. Vedel S. Junker B.B. Kahn O. Pedersen 《Diabetic medicine》1993,10(8):699-706
Studies in normal man and rodents have demonstrated that the expression of the dominant glucose transporter in skeletal muscle, GLUT4, is regulated by insulin at supraphysiological circulating levels. The present study was designed to determine whether intensified insulin replacement therapy for 24 h given to patients with Type 1 diabetes in poor metabolic control was associated with an adaptive regulation of GLUT4 mRNA and protein levels in vastus lateralis muscle. Nine Type 1 diabetic patients with a mean HbA1c of 10.3% were included in the protocol. After intensified treatment with soluble insulin for 24 h the fasting plasma glucose concentration decreased from 20.8 ± 2.3 (SD) to 8.7 ± 2.3 mmol 1?1 whereas the fasting serum insulin level increased from 0.06 ± 0.02 to 0.17 ± 0.09 nmol 1?1 However, despite a 2.8-fold increase in serum insulin levels and more than a halving of the plasma glucose concentration for at least 15 h no significant alterations occurred in the amount of GLUT4 protein (0.138 ± 0.056, poor control vs 0.113 ± 0.026 arb. units, improved control, p = 0.16) or GLUT4 mRNA (96432 ± 44985, poor control vs 81395 ± 25461 arb. units, improved control, p = 0.54). These results suggest, that in spite of evidence that high insulin levels affect GLUT4 expression in muscle, changes in serum insulin within the physiological range do not play a major role in the short-term regulation of GLUT4 expression in Type 1 diabetic patients. 相似文献
110.
Nettelbladt P 《Convulsive therapy》1988,4(2):160-168
This investigation studies number of treatments and seizure duration during a course of unilateral electroconvulsive therapy (ECT) in 82 inpatients with major depressive disorders. Therapy with antidepressants or benzodiazepines preceding ECT was neither related to number of treatments nor to seizure duration. An average dose of methohexital higher than 1.2 mg/kg body weight was associated both with an increased number of treatments and a shorter average seizure duration. Concurrent therapy with neuroleptics was related to a reduced number of treatments. Patients in social class I, more often than others, received fewer treatments. 相似文献