全文获取类型
收费全文 | 1832612篇 |
免费 | 129586篇 |
国内免费 | 9971篇 |
专业分类
耳鼻咽喉 | 25396篇 |
儿科学 | 51749篇 |
妇产科学 | 49097篇 |
基础医学 | 254558篇 |
口腔科学 | 52472篇 |
临床医学 | 160906篇 |
内科学 | 358399篇 |
皮肤病学 | 37445篇 |
神经病学 | 139988篇 |
特种医学 | 72021篇 |
外国民族医学 | 451篇 |
外科学 | 286507篇 |
综合类 | 53751篇 |
现状与发展 | 21篇 |
一般理论 | 482篇 |
预防医学 | 128143篇 |
眼科学 | 42496篇 |
药学 | 140069篇 |
118篇 | |
中国医学 | 10139篇 |
肿瘤学 | 107961篇 |
出版年
2021年 | 16004篇 |
2019年 | 15018篇 |
2018年 | 20416篇 |
2017年 | 16661篇 |
2016年 | 17400篇 |
2015年 | 21260篇 |
2014年 | 29070篇 |
2013年 | 40850篇 |
2012年 | 55908篇 |
2011年 | 59143篇 |
2010年 | 36493篇 |
2009年 | 33974篇 |
2008年 | 54833篇 |
2007年 | 57182篇 |
2006年 | 57699篇 |
2005年 | 55762篇 |
2004年 | 52050篇 |
2003年 | 49986篇 |
2002年 | 48464篇 |
2001年 | 90641篇 |
2000年 | 93323篇 |
1999年 | 78845篇 |
1998年 | 20596篇 |
1997年 | 18575篇 |
1996年 | 18289篇 |
1995年 | 17074篇 |
1994年 | 16136篇 |
1993年 | 14648篇 |
1992年 | 59720篇 |
1991年 | 57196篇 |
1990年 | 55458篇 |
1989年 | 53749篇 |
1988年 | 49316篇 |
1987年 | 48382篇 |
1986年 | 45575篇 |
1985年 | 43458篇 |
1984年 | 31641篇 |
1983年 | 26881篇 |
1982年 | 14986篇 |
1979年 | 28679篇 |
1978年 | 19679篇 |
1977年 | 16756篇 |
1976年 | 15147篇 |
1975年 | 16684篇 |
1974年 | 20168篇 |
1973年 | 19078篇 |
1972年 | 18153篇 |
1971年 | 16928篇 |
1970年 | 16285篇 |
1969年 | 15265篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
K. Sjölund S. Fasth R. Ekman L. Hultén H. Jiborn S. Nordgren & F. Sundler 《Neurogastroenterology and motility》1997,9(3):143-150
Tissue specimens from the large bowel of 18 patients with long-standing slow transit constipation were investigated to determine the distribution and density of several neuropeptides and amines in the enteric nerve system, and also of endocrine cells in comparison to normal individuals. CGRP (calcitonin gene-related peptide), galanin, glucagon, GRP (gastrin-releasing peptide), metenkephalin, motilin, neuropeptide Y (NPY), PACAP, peptide YY (PYY), serotonin, somatostatin, substance P and VIP were studied by immunohistochemistry. Tissue concentrations of VIP, substance P and galanin were also measured by radioimmunoassay. Significantly increased VIP, SP and galanin contents were found in specimens from the ascending colon. Levels of VIP and galanin were also increased in the transverse colon. Immunohistochemistry revealed only marginal changes with an increased density of PACAP nerve fibres in the smooth muscle and of VIP and PACAP nerves in the myenteric plexus of the transverse colon. In the descending colon substance P and NPY immunoreactivity were also increased in the myenteric plexus while the density of VIP nerve fibres was reduced in the mucosa/submucosa. The frequency of PYY-containing cells and the 5-HT-containing cells in the ascending colon was significantly increased in the constipated patients. 相似文献
102.
Piecewise constant incidence models were developed to estimate the force of infection in women from age-and time-specific antenatal or neonatal seroprevalence data. Differential inclusion of infected women in sero-surveys compared to uninfected women was taken into account, with respect to both changes in inclusion rate following infection, and changes in relative inclusion rate over calendar time. These models were applied to anonymous HIV seroprevalence data collected from neonates born to black and Hispanic women in New York City 1988-1992, with incidence and fertility parameters estimated by maximum likelihood. Estimates of inclusion rate parameters accorded well with what is known about the natural history of HIV. The data could not distinguish between additive and multiplicative combination of the effects of age and time on incidence. Incidence was strongly dependent on age with the highest incidence in women aged 20-34 years. There was strong evidence that incidence had been falling in Hispanic women since 1982-1984. The results illustrate the extent to which trends in incidence over time may be confounded by changes in the relative inclusion rate of infected and uninfected women. 相似文献
103.
V. S. Akhunov T. V. Mirenburg X. D. Krasnopolskaya 《Journal of inherited metabolic disease》1994,17(1):104-111
Summary GM1- and GM2-gangliosides were isolated from brain and radio-labelled. The labelled moieties were localized by hydrolysis with lysosomal enzymes, followed by thin-layer chromatography of the products. High-resolution loading tests with labelled gangliosides were developed and found to differentiate infantile and juvenile forms of GM1- and GM2-gangliosidoses as well as the identification of B, O and AB types of GM2-gangliosidosis. 相似文献
104.
F W Fraunfelder F T Fraunfelder D R Illingworth 《The British journal of ophthalmology》1995,79(1):54-56
In a retrospective survey of patients taking medication for hyperlipidaemia, those taking niacin (nicotinic acid) were more likely (p < 0.05) to report sicca syndromes, blurred vision, eyelid oedema, and macular oedema compared with those who never took niacin. Additionally, 7% of those taking niacin discontinued the drug owing to adverse ocular side effects, while none of the other lipid lowering agents were found to cause these side effects (p = 0.016). Data from spontaneous reporting systems support a possible association of decreased vision, cystoid macular oedema, sicca-like symptoms, discoloration of the eyelids with or without periorbital or eyelid oedema, proptosis, loss of eyebrow or eyelashes, and superficial punctate keratitis with the use of niacin in high doses. Decreased vision may be marked, and if the drug is not discontinued, may progress to cystoid macular oedema. All ocular side effects listed above are reversible if the association with niacin is recognised and the drug is discontinued; both the incidence and severity of the ocular side effects seem to be dose dependent. 相似文献
105.
106.
C Schmitt J Brachmann W Saggau T Beyer B Waldecker K Scharowski T Hilbel M Montero B Offner W Sch?ls 《Zeitschrift für Kardiologie》1991,80(11):665-672
In 41 patients with recurrent sustained ventricular tachycardia and/or ventricular fibrillation an integrated pacemaker-defibrillator-system (PCD, Medtronic, model 7216 A or 7217 B) was implanted. In 21 out of 24 (88%) patients a new transvenous implantation technique in combination with a subcutaneous patch electrode was used. The implanted devices comprise antibradycardiac pacemaker functions, two different forms of antitachycardiac pacemaker functions (ramp and burst pacing), and internal cardioversion or defibrillation capabilities. During a mean follow-up of 8 months 147 episodes of ventricular tachycardia were detected, 131 of them were terminated successfully by antitachycardiac pacing; in 13 episodes internal cardioversion was applied to revert ventricular tachycardia. Twenty-seven episodes of ventricular fibrillation or rapid ventricular tachycardia (greater than 200/min) were detected and successfully terminated by internal defibrillation. In six patients with intermittent rapid atrial fibrillation, change of antiarrhythmic therapy was required to avoid activation of the device. The new integrated pacemaker-defibrillator systems improve therapy in patients with life-threatening tachyarrhythmias by reducing the number of internal cardioversions/defibrillations; the non-thoracotomy approach reduces the post operative risk. 相似文献
107.
Of 431 patients with gastric cancer observed in our institution, 23 (5.3%) had early gastric cancer (EGC). Macroscopic presentation, histology, depth of invasion, and lymph node involvement were evaluated in all the cases. All patients underwent surgery and an intensive follow-up was performed. Five of the 23 patients progressed, and the risk factors were examined. Histology seemed to be the main prognostic factor in our study, since intestinal type of EGC was associated to a significantly better prognosis. Total gastrectomy is indicated in the proximal localization of EGC, and should perhaps be performed also in cases presenting undifferentiated histology. 相似文献
108.
Two-color flow cytometry was carried out to determine the correlation between cell-mediated immunity and the levels of proteinuria in 30 patients with membranous nephropathy. Lymphocyte subpopulations were measured by two-color flow cytometry using various monoclonal antibodies of the Leu series. Clinically, the patients were divided into four stages as follows: 1. untreated nephrotic stage, 2. prednisolone (PSL) treated nephrotic stage, 3. persistent proteinuric stage (incomplete remission, ICR) and 4. complete remission (CR). Two-color flow cytometry showed a significant decrease in Leu 2a+15+ (suppressor T) cells and relative increase in Leu 3a+8+ (suppressor inducer T) cells in the untreated nephrotic stage. The mean Leu 3a+8-/Leu 2a+15+ (helper/suppressor) cell ratio was normalized in the persistent proteinuric stage or complete remission after treatment with PSL. Patients with membranous nephropathy showed a significant elevation of Leu 2a+DR+ cells after treatment with PSL. The abnormalities of suppressor T cells and suppressor inducer T cells in the peripheral blood appear to reflect the levels of proteinuria in patients with membranous nephropathy. It was concluded that PSL might stimulate Leu 2a positive cells and then increase the number of Leu 2a+15+ cells in the peripheral blood of patients with membranous nephropathy. 相似文献
109.
Premalignant lesions and nonsquamous malignancy of the penis and carcinoma of the scrotum. 总被引:2,自引:0,他引:2
P F Schellhammer G H Jordan E L Robey J T Spaulding 《The Urologic clinics of North America》1992,19(1):131-142
Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma. 相似文献
110.