全文获取类型
收费全文 | 6443篇 |
免费 | 394篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 87篇 |
儿科学 | 176篇 |
妇产科学 | 293篇 |
基础医学 | 829篇 |
口腔科学 | 146篇 |
临床医学 | 488篇 |
内科学 | 1596篇 |
皮肤病学 | 207篇 |
神经病学 | 481篇 |
特种医学 | 223篇 |
外科学 | 1017篇 |
综合类 | 43篇 |
一般理论 | 2篇 |
预防医学 | 236篇 |
眼科学 | 81篇 |
药学 | 501篇 |
中国医学 | 9篇 |
肿瘤学 | 460篇 |
出版年
2023年 | 35篇 |
2022年 | 70篇 |
2021年 | 127篇 |
2020年 | 83篇 |
2019年 | 131篇 |
2018年 | 132篇 |
2017年 | 100篇 |
2016年 | 113篇 |
2015年 | 115篇 |
2014年 | 167篇 |
2013年 | 224篇 |
2012年 | 356篇 |
2011年 | 287篇 |
2010年 | 177篇 |
2009年 | 187篇 |
2008年 | 317篇 |
2007年 | 305篇 |
2006年 | 293篇 |
2005年 | 284篇 |
2004年 | 309篇 |
2003年 | 255篇 |
2002年 | 240篇 |
2001年 | 188篇 |
2000年 | 250篇 |
1999年 | 206篇 |
1998年 | 72篇 |
1997年 | 56篇 |
1996年 | 79篇 |
1995年 | 66篇 |
1994年 | 44篇 |
1993年 | 49篇 |
1992年 | 150篇 |
1991年 | 162篇 |
1990年 | 139篇 |
1989年 | 122篇 |
1988年 | 114篇 |
1987年 | 87篇 |
1986年 | 81篇 |
1985年 | 85篇 |
1984年 | 64篇 |
1983年 | 63篇 |
1982年 | 28篇 |
1981年 | 35篇 |
1979年 | 43篇 |
1976年 | 28篇 |
1975年 | 40篇 |
1974年 | 30篇 |
1973年 | 28篇 |
1970年 | 27篇 |
1966年 | 26篇 |
排序方式: 共有6875条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
I Romagnoli F Gigliotti A Galarducci B Lanini R Bianchi D Cammelli G Scano 《The European respiratory journal》2004,24(3):453-460
No direct measurements of the pressures produced by the ribcage muscles, the diaphragm and the abdominal muscles during hyperventilation have been reported in patients with ankylosing spondylitis. Based on recent evidence indicating that abdominal muscles are important contributors to stimulation of ventilation, it was hypothesised that, in ankylosing spondylitis patients with limited ribcage expansion, a respiratory centre strategy to help the diaphragm function may involve coordinated action of this muscle with abdominal muscles. In order to validate this hypothesis, the chest wall response to a hypercapnic/hyperoxic rebreathing test was assessed in six ankylosing spondylitis patients and seven controls by combined analysis of: 1) chest wall kinematics, using optoelectronic plethysmography, this system is accurate in partitioning chest wall expansion into the contributions of the ribcage and the abdomen; and 2) respiratory muscle pressures, oesophageal, gastric and transdiaphragmatic (Pdi); the pressure/volume relaxation characteristics of both the ribcage and the abdomen allowed assessment of the peak pressure of both inspiratory and expiratory ribcage muscles, and of the abdominal muscles. During rebreathing, chest wall expansion increased to a similar extent in patients to that in controls; however, the abdominal component increased more and the ribcage component less in patients. Peak inspiratory ribcage, but not abdominal, muscle pressure was significantly lower in patients than in controls. End-inspiratory Pdi increased similarly in both groups, whereas inspiratory swings in Pdi increased significantly only in patients. No pressure or volume signals correlated with disease severity. The diaphragm and abdominal muscles help to expand the chest wall in ankylosing spondylitis patients, regardless of the severity of their disease. This finding supports the starting hypothesis that a coordinated response of respiratory muscle activity optimises the efficiency of the thoracoabdominal compartment in conditions of limited ribcage expansion. 相似文献
15.
Repetitive conservative surgery for recurrence of endometriosis 总被引:4,自引:0,他引:4
G B Candiani L Fedele P Vercellini S Bianchi G Di Nola 《Obstetrics and gynecology》1991,77(3):421-424
We evaluated the recovery of fertility and the relief of pain symptoms in a long-term follow-up of 42 women undergoing repetitive conservative surgery for recurrent endometriosis. The mean age of the patients was 31.1 +/- 4.3 years. At the time of their second operation the disease was stage IV in 14 women, stage III in 25, and stage I in three. After reoperation, the patients were followed for a mean period of 41.8 +/- 30.3 months. Pain symptoms returned in eight women, dysmenorrhea and deep dyspareunia in eight, and pelvic pain in seven. Eight of the 28 women (28.6%) who attempted to conceive achieved a total of 13 pregnancies. The corrected pregnancy rate was 35%, and the cumulative rate at 27 months was 30.7%. A third operation was necessary in six women after a mean period of 35 months. Conservative surgery is an effective therapeutic option for infertile patients with recurrent endometriosis. 相似文献
16.
L Beani C Bianchi P G Baraldi S Manfredini G P Pollini 《Arzneimittel-Forschung》1990,40(11):1187-1191
The protection by pyroglutamic acid (CAS 98-79-3) and derivatives Ia-i (injected i.p.) against glutamate- and NMDA (N-methyl-D-aspartate) (i.c.v.) induced seizures in mice has been studied in comparison with known antiepileptics and antagonists of excitatory aminoacids. The potency of pyroglutamic acid and some derivatives (Id,f,g,h) against glutamate-induced convulsions was similar to that shown by glutamic acid diethylester and by valproic acid. Interestingly, pyroglutamic acid did not affect NMDA-induced convulsions which were well antagonized by both 2-amino-5-phosphono valeric acid and by diazepam. Thus, pyroglutamic acid may represent the starting for synthesis of excitatory aminoacid antagonists acting at non NMDA receptors. 相似文献
17.
We determined morphine plasma concentrations in 6 cancer patients before and with administration of diclofenac for 5 days. The non-steroidal anti-inflammatory drug does not modify morphine bioavailability. This observation suggests that diclofenac can be used in association with morphine during cancer pain treatment, without increasing the risk of overdosage or side effects of the opiate. 相似文献
18.
The new calcium antagonist Rec 15/2375, supposed to be selective for the vascular tissue, was compared to nifedipine, a non-selective agent that reduces blood pressure and impairs cardiac inotropism as well. Six rabbits, chronically catheterized and continuously monitored for systemic blood pressure, heart rate and the isovolumic contractility index dP/Tmax, were alternatively treated with Rec 15/2375 and nifedipine, according to a randomized cross-over design. Both drugs were given under either autonomically intact (AI) or suppressed (AS) heart function control, induced by cholinergic and beta-adrenoceptor blockade. The two agents reduced mean arterial blood pressure comparably and dose-dependently (P less than 0.01) under both experimental conditions (from 10 to 40%), thus causing heart rate to increase reflexly (P less than 0.01), similarly between drugs in AI rabbits, whereas the AS manoeuvre totally abolished such a response. Cardiac contractility, on the other hand, displayed opposing behaviour between the two drugs. Rec 15/2375 caused mild but significant (P less than 0.01) increases, which were similar at all doses (+10, +15%) and insensitive to the AS intervention, whereas nifedipine caused dose-dependent reductions (from -10 to -60%; P less than 0.01) of comparable intensity as mean blood pressure decrease in both protocols. We conclude that Rec 15/2375 effectively lowers blood pressure with no impairment, unlike nifedipine, of cardiac inotropism and we discuss the possibility that dP/dTmax may be increased as a result of the haemodynamic rearrangement following after-load reduction. 相似文献
19.
A clinical, microbiologic, and radiographic study of deep caries lesions after incomplete caries removal. 总被引:3,自引:0,他引:3
Marisa Maltz Elenara F de Oliveira Vania Fontanella Rafael Bianchi 《Quintessence international, dental digest》2002,33(2):151-159
OBJECTIVE: Clinical, radiographic, and microbiologic changes in deep caries lesions were assessed after incomplete carious dentin removal and tooth sealing. METHOD AND MATERIALS: Thirty-two teeth with deep caries lesions were studied. Treatment consisted of incomplete excavation of the demineralized dentin, application of calcium hydroxide, and sealing for a 6- to 7-month period. The color and consistency of the dentin were clinically assessed. Differences in radiographic density were assessed by digital image subtraction. Microbiologic samples were obtained from the demineralized dentin before the temporary sealing and after the experimental period. The samples were cultivated on blood agar under aerobic and anaerobic conditions, in Mitis Salivarius agar, and Rogosa selective Lactobacillus agar. RESULTS: Two cases were lost during the study; one presented pulpal necrosis. In the other case, there was pulpal exposure during removal of provisional sealing. In all teeth, the initial demineralized dentin was soft and wet; one lesion was yellow, 21 were light brown, and eight were dark brown. After treatment, the dentin was dry, and 80.00% of specimens were hard, 16.67% were leathery, and 3.33% remained soft. The dentin was light brown in five teeth and dark brown in 25. There was a statistically significant mean difference in radiographic density (pixel intensity), 88.77 +/- 7.02 in the control areas and 94.66 +/- 6.75 in the test areas. The counts of anaerobic and aerobic bacteria, lactobacilli, and Streptococci mutans had decreased significantly by the end of treatment. CONCLUSION: Incomplete removal of carious dentin and subsequent tooth sealing resulted in the arrest of the lesions, suggesting that complete dentinal caries lesion removal is not essential to the control of caries lesions. 相似文献
20.
Annalisa Volpi Francesco Bacci Angelo Paradiso Luca Saragoni Emanuela Scarpi Monica Ricci Mirella Aldi Simonetta Bianchi Pietro Muretto Fiorella Nuzzo Gianni Simone Anita Mangia Francesco Schittulli Dino Amadori 《Modern pathology》2004,17(9):1038-1044
Available results highlight the lack of good level of evidence studies on the pure prognostic value of histological grade. In the present study, the prognostic relevance of histological grade and of its three components, tubule formation, nuclear pleomorphism and mitotic count, was analyzed in a series of 372 patients with node-negative breast cancer treated with locoregional therapy alone until early relapse. Histological grade was determined blindly by two observers and discordance between evaluations was resolved after joint review using a multihead microscope. No relation was observed between histological grade and any of its three components and disease-free survival. Conversely, a significant relation was observed between histological grade and distant metastasis-free survival (at 6 years, 94, 86 and 76% for grades 1, 2 and 3, respectively, P=0.013) as well as overall survival (98, 90 and 86%, P=0.001). A breakdown analysis as a function of the three components showed that neither tubule formation nor nuclear pleomorphism was associated with prognosis, and only mitotic count strongly influenced both distant metastasis-free survival (91, 82 and 74%, P=0.014) and overall survival (97, 87 and 85%, P=0.011). Histological grade suffers from a much higher subjectivity than any other microscopic evaluation of biomarkers as it is the sum of three different morphological features. Within the Italian Network for Quality Assessment of Tumor Biomarkers program we observed that histological grade is an independent prognostic variable, but also that this role is ascribable only to the number of mitotic figures. In conclusion, due to the ever smaller size of diagnosed breast cancers, resulting in less cancer tissue for biofunctional and molecular analysis, mitotic count evaluated under strict quality control conditions seems to be an accurate and feasible prognostic variable. 相似文献