全文获取类型
收费全文 | 5275篇 |
免费 | 301篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 192篇 |
妇产科学 | 126篇 |
基础医学 | 614篇 |
口腔科学 | 153篇 |
临床医学 | 391篇 |
内科学 | 1738篇 |
皮肤病学 | 66篇 |
神经病学 | 452篇 |
特种医学 | 97篇 |
外科学 | 604篇 |
综合类 | 16篇 |
一般理论 | 1篇 |
预防医学 | 220篇 |
眼科学 | 27篇 |
药学 | 388篇 |
中国医学 | 7篇 |
肿瘤学 | 485篇 |
出版年
2023年 | 31篇 |
2022年 | 58篇 |
2021年 | 136篇 |
2020年 | 58篇 |
2019年 | 125篇 |
2018年 | 130篇 |
2017年 | 102篇 |
2016年 | 111篇 |
2015年 | 106篇 |
2014年 | 168篇 |
2013年 | 236篇 |
2012年 | 295篇 |
2011年 | 284篇 |
2010年 | 163篇 |
2009年 | 155篇 |
2008年 | 235篇 |
2007年 | 304篇 |
2006年 | 290篇 |
2005年 | 297篇 |
2004年 | 234篇 |
2003年 | 215篇 |
2002年 | 218篇 |
2001年 | 167篇 |
2000年 | 169篇 |
1999年 | 154篇 |
1998年 | 46篇 |
1997年 | 47篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 37篇 |
1993年 | 30篇 |
1992年 | 99篇 |
1991年 | 61篇 |
1990年 | 77篇 |
1989年 | 63篇 |
1988年 | 58篇 |
1987年 | 66篇 |
1986年 | 50篇 |
1985年 | 53篇 |
1984年 | 44篇 |
1983年 | 53篇 |
1982年 | 20篇 |
1979年 | 26篇 |
1978年 | 20篇 |
1976年 | 17篇 |
1975年 | 25篇 |
1974年 | 28篇 |
1971年 | 16篇 |
1970年 | 20篇 |
1968年 | 16篇 |
排序方式: 共有5605条查询结果,搜索用时 0 毫秒
41.
G Morone A Tazzi G Carella A Ghisolfi R Colombo 《Journal fran?ais d'ophtalmologie》1985,8(8-9):555-558
The authors describe the pathological changes in the vascular structures of the ciliary body occuring in diabetes mellitus. The lesions consist of a quantitative reduction in the number of vessels and in modifications of diameter and arborisation. Changes include sectoral thinning, isolated and grouped aneuryms and marked tortuosity. These findings are thought to be constant in the diabetic patient and are probably involved in the various aspects of diabetic eye disease affecting other structures besides the ciliary body. The group of vascular changes in the ciliary body in diabetes may aptly be termed "diabetic ciliopathy". 相似文献
42.
The possibility of a preferential distribution of projections from the preoptic-suprachiasmatic region (POA-Sch) to the median eminence in the male rat was studied using autoradiographic and computer procedures. A cocktail of [3H]leucine-[3H]proline was injected into the POA-Sch. Animals were killed after either 1, 4, or 24 h of incorporation time (IT). The number of silver grains per 25-micron square was counted throughout the median eminence. Squares with silver grain densities at or above the 75 percentile of the population for any given IT group were labeled as "concentrating areas." The distribution of these concentrating areas in median eminence tissue was analyzed utilizing univariate procedures. Visual inspection of the distribution of silver grain densities in a rostrocaudal fashion indicated the likelihood of uneven distribution; however, these differences were not statistically significant. In the dorsoventral plane, results indicated that the highest silver grain density was at 50 to 75 micron from the floor of the 3rd ventricle. Such distribution was apparent both ipsi- and contralateral to the injection site, but was greater on the ipsilateral side. 相似文献
43.
Galassi G. Modena M. G. Benassi A. Nemni R. Gibertoni M. Volpi G. Colombo A. 《The Italian Journal of Neurological Sciences》1986,7(1):125-132
Two females mother and daughter, were affected by a neuromuscular disorder, characterized by slow progression, humeroperoneal weakness and wasting, limited neck flexion, elbow and ankle joint contractures, cardiopathy and myopathic pattern on EMG. Muscle histology and histochemistry showed type I fiber atrophy and predominance in both. Cardiac abnormalities, in the first case, were suggestive of a hypertrophic cardiomyopathy while in the second hypotension and chronic bradycardia were present.Neurological signs, EMG and morphology seemed to point to a genetic variant of the form of dystrophy named Emergy-Dreifuss disease.The mode of transmission and cardiac abnormalities, however, raise the problem of variability even in this well-defined, usually X-linked, disorder.
Sommario Questa è la prima descrizione di madre e figlia affette da una infrequente malattia muscolare, caratterizzata da progressione lenta, ipostenia con atrofia a distribuzione omero-peroneale, presenza di contratture articolari, cardiopatia e pattern miopatico dell'EMG.Istologia e istochimica muscolare hanno mostrato in entrambi i soggetti atrofia e predominanza delle fibre del I tipo. Le anormalità cardiologiche rilevate nel 1° caso, erano a favore di una cardiomiopatia ipertrofica, mentre nel secondo caso erano presenti ipotensione e bradicardia.Segni neurologici, elettromiografici, reperti istologici ed istochimici sembrano configurare nelle nostre pazienti una variante genetica della forma di distrofia muscolare chiamata Emery-Dreifuss disease. Tuttavia, la modalità di trasmissione e il tipo delle anormalità cardiologiche, diverse nelle due pazienti, sollevano il problema di variabilità fenotipiche, anche in entità clinico-genetiche usualmente ben definite quali la malattia di Emery-Dreifuss.相似文献
44.
R C Avanzo G Chierego C Marchetti F Pozza F Colombo A Benedetti A Zanardo 《La Radiologia medica》1984,70(3):124-129
At least two fundamental requirements must subsist for every stereotaxic radiotherapy treatment: 1) a capacity to administer extremely high doses of radiation to small areas which have been precisely defined in three dimensions; 2) the presence of a steep gradient between adjacent isodose curves so that damage to the tissues close to the target may be reduced to the minimum. The authors have built a special stereotaxic device for the fixing of the head of the patient (together with the chosen intracranial target), once the indispensable neuroradiological evaluations and bioptic controls have been effected, at the isocenter of a linear accelerator (Varian Clinac 4). Once the dimensions of the collimator have been chosen in accordance with the volume and the three dimensional conformation of the target and the dose to be administered has been decided upon in accordance with the histological nature of the lesion, both the linear accelerator and the patient are rotated about the isocenter of the therapy unit. It this way it is possible to reach extremely high dosages with very steep isodose gradients, centered exclusively upon the target ("gamma knife"). The procedure employed is described in full. The dosimetric evaluations which preceded the use of the set-up in clinical practice are illustrated as well. The advantages that this technique offers when compared with interstitial brachytherapy and/or Leksell's radiosurgical procedures are stressed. The described procedure, which is entirely bloodless and thus applicable also to high vascularized lesions, has so far been used in a limited series of cases. 相似文献
45.
46.
Chiara Di Lorenzo Francesca Colombo Simone Biella Creina Stockley Patrizia Restani 《Nutrients》2021,13(1)
Polyphenols are a group of phytochemicals with potential health-promoting effects. They are classified as flavonoid (flavonols, flavanols, flavones, flavanones, isoflavones, and anthocyanins) and non-flavonoid molecules (phenolic acids, hydroxycinnamic acids, lignans, stilbenes, and tannins). Although an increasing number of trials have shown a correlation among polyphenol consumption and a reduction in risk factors for chronic diseases, discrepancies in explaining their positive effects have been found in terms of the bioavailability. In fact, polyphenols show a low bioavailability due to several factors: interaction with the food matrix, the metabolic processes mediated by the liver (phase I and II metabolism), intestine and microbiota. On the other hand, the biological activities of phenol compounds may be mediated by their metabolites, which are produced in vivo, and recent studies have confirmed that these molecules may have antioxidant and anti-phlogistic properties. This review discusses the studies performed in vivo, which consider the polyphenol bioavailability and their different food sources. Factors influencing the biological effects of the main classes of polyphenols are also considered. 相似文献
47.
F. Pisano P. Gontero R. Sylvester S. Joniau V. Serretta S. Larré S. Di Stasi B. van Rhijn A. Witjes A. Grotenhuis R. Colombo A. Briganti M. Babjuk V. Soukup P.U. Malmstrom J. Irani N. Malats J. Baniel J. Palou 《Actas urologicas espa?olas》2021,45(6):473-478
Introduction and objectivesThe goals of transurethral resection of a bladder tumor (TUR) are to completely resect the lesions and to make a correct diagnosis in order to adequately stage the patient. It is well known that the presence of detrusor muscle in the specimen is a prerequisite to minimize the risk of under staging.Persistent disease after resection of bladder tumors is not uncommon and is the reason why the European Guidelines recommended a re-TUR for all T1 tumors. It was recently published that when there is muscle in the specimen, re-TUR does not influence progression or cancer specific survival.We present here the patient and tumor factors that may influence the presence of residual disease at re-TUR.Material and methodsIn our retrospective cohort of 2451 primary T1G3 patients initially treated with BCG, pathology results for 934 patients (38.1%) who underwent re-TUR are available. 74% had multifocal tumors, 20% of tumors were more than 3 cm in diameter and 26% had concomitant CIS.In this subgroup of patients who underwent re-TUR, there was no residual disease in 267 patients (29%) and residual disease in 667 patients (71%): Ta in 378 (40%) and T1 in 289 (31%) patients. Age, gender, tumor status (primary/recurrent), previous intravesical therapy, tumor size, tumor multi-focality, presence of concomitant CIS, and muscle in the specimen were analyzed in order to evaluate risk factors of residual disease at re-TUR, both in univariate analyses and multivariate logistic regressions.ResultsThe following were not risk factors for residual disease: age, gender, tumor status and previous intravesical chemotherapy. The following were univariate risk factors for presence of residual disease: no muscle in TUR, multiple tumors, tumors > 3 cm, and presence of concomitant CIS. Due to the correlation between tumor multi-focality and tumor size, the multivariate model retained either the number of tumors or the tumor diameter (but not both), p < 0.001. The presence of muscle in the specimen was no longer significant, while the presence of CIS only remained significant in the model with tumor size, p < 0.001.ConclusionsThe most significant factors for a higher risk of residual disease at re-TUR in T1G3 patients are multifocal tumors and tumors more than 3 cm. Patients with concomitant CIS and those without muscle in the specimen also have a higher risk of residual disease. 相似文献
48.
In vitro and in vivo effects of cisplatin on the generation of lymphokine-activated killer cells 总被引:1,自引:0,他引:1
P Allavena P Pirovano C Bonazzi N Colombo A Mantovani M D'Incalci 《Journal of the National Cancer Institute》1990,82(2):139-142
Pretreatment of human peripheral blood lymphocytes (PBL) with cisplatin (CDDP) before in vitro culture with interleukin-2 (IL-2) inhibited the generation of lymphokine-activated killer (LAK) cells and strongly inhibited proliferation. This inhibition was dose dependent, was significant only at concentrations greater than 6 microM, and it required exposure to the drug for more than 1 hour. This period of IL-2 unresponsiveness was maximum at 6 hours, but was spontaneously recovered within 24-48 hours and was more rapidly restored by increasing dosages of IL-2. Because inhibition of the generation of LAK cells by CDDP was observed only at relatively high levels of exposure to the drug (greater than 6 microM for greater than 1 hr), it was important that we explore the in vivo significance of these findings. The peripheral blood lymphocytes from patients bearing ovarian adenocarcinoma collected 1 hour after an iv infusion of 50 mg of CDDP/m2 were not inhibited, compared with those collected immediately before therapy. Relatively high levels of exposure to CDDP are required for inhibition of the generation of new cytotoxic effectors, most likely because of its antiproliferative effect. These results may bear relevance to approaches involving the combined use of CDDP and IL-2-LAK. 相似文献
49.
50.
Long, interlaminar, astroglial processes and its patterned organization in the striate cortex of adult primates was previously described. Loss of visual input following bilateral retinal detachment and degeneration in an adult Cebus apella monkey resulted three months later in reduction of interlaminar processes immunoreactive to Glial Fibrillary Acid Protein antibody, loss of the honeycomb-like pattern normally present in tangential sections, and loss of high density patches of terminal segments of those processes in the opercular striate. These results further indicate the highly interactive nature of neuron-glial cerebral cortex architecture, and the dynamic regulation of astroglial interlaminar processes. 相似文献