全文获取类型
收费全文 | 14263篇 |
免费 | 986篇 |
国内免费 | 100篇 |
专业分类
耳鼻咽喉 | 130篇 |
儿科学 | 445篇 |
妇产科学 | 216篇 |
基础医学 | 1762篇 |
口腔科学 | 522篇 |
临床医学 | 1239篇 |
内科学 | 3343篇 |
皮肤病学 | 421篇 |
神经病学 | 1210篇 |
特种医学 | 564篇 |
外科学 | 2394篇 |
综合类 | 35篇 |
一般理论 | 1篇 |
预防医学 | 924篇 |
眼科学 | 153篇 |
药学 | 716篇 |
中国医学 | 16篇 |
肿瘤学 | 1258篇 |
出版年
2023年 | 154篇 |
2022年 | 254篇 |
2021年 | 567篇 |
2020年 | 275篇 |
2019年 | 447篇 |
2018年 | 545篇 |
2017年 | 363篇 |
2016年 | 364篇 |
2015年 | 412篇 |
2014年 | 553篇 |
2013年 | 653篇 |
2012年 | 937篇 |
2011年 | 1001篇 |
2010年 | 561篇 |
2009年 | 526篇 |
2008年 | 818篇 |
2007年 | 808篇 |
2006年 | 769篇 |
2005年 | 774篇 |
2004年 | 685篇 |
2003年 | 638篇 |
2002年 | 532篇 |
2001年 | 299篇 |
2000年 | 271篇 |
1999年 | 229篇 |
1998年 | 118篇 |
1997年 | 105篇 |
1996年 | 84篇 |
1995年 | 75篇 |
1994年 | 78篇 |
1993年 | 66篇 |
1992年 | 139篇 |
1991年 | 135篇 |
1990年 | 117篇 |
1989年 | 109篇 |
1988年 | 104篇 |
1987年 | 99篇 |
1986年 | 88篇 |
1985年 | 79篇 |
1984年 | 60篇 |
1983年 | 56篇 |
1982年 | 37篇 |
1981年 | 30篇 |
1980年 | 21篇 |
1979年 | 37篇 |
1978年 | 27篇 |
1977年 | 32篇 |
1975年 | 27篇 |
1973年 | 24篇 |
1972年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
C Diaz de la Guardia F Alba C de Linares D Nieto-Lugilde J López Caballero 《Journal of investigational allergology & clinical immunology》2006,16(1):24-33
Cupressaceae pollen has been cited in recent years as one of the major airborne allergens of the Mediterranean region, prompting us to conduct an exhaustive analysis on the aerobiological behaviour of this pollen in the Iberian Peninsula and the repercussion that it has had on the atopic population. The aerobiological study, performed from 1996 to 2003 in the city of Granada (S. Spain), used a volumetric Hirst collector. The results indicate that this pollen is present in the air most of the year, registering a high incidence during the winter months. This type of pollen behaved irregularly in the air, fluctuating yearly, seasonally, and within the same day. Temperature and humidity were the parameters that most directly influence the variability of this allergen, while rainfall prior to flowering increased pollen production. The predictive models used estimated a high percentage of the levels reached over the short term by this pollen in the atmosphere of Granada. The clinical study performed with atopic patients showed that some 30% of the population with pollinosis are sensitive to Cupressaceae pollen, affecting people of both genders equally. On the other hand, the most sensitive age group was 21-40 years of age, while children and the elderly registered almost negligible values. Most of the sensitive subjects resided within the city or in the metropolitan area, where environmental pollution reached high levels, while the pathology was found to be less frequent in rural zones. The most frequent symptoms were upper-respiratory ailments and an asthmatic profile. 相似文献
34.
F G Diaz R D Fessler B Velardo C Kennedy H Wilner 《Journal of clinical neuroscience》1994,1(4):222-230
Aneurysms arising from the internal carotid circulation represent 85% of all intracranial aneurysms. The intimate relationship of the internal carotid artery and its branches with the brain and cranial nerves, and the distribution of the internal carotid artery flow, make these aneurysms challenging, and potentially complicated in their surgical management. Great attention to detail, and clear understanding of the operative anatomy of the carotid system, facilitate the safe and successful treatment of these aneurysms. The surgical experience with 475 anterior circulation aneurysms treated from 1980 to 1992 is presented. The aneurysms arose from the internal carotid artery: 230(40%), middle cerebral artery: 152(32%), and anterior cerebral artery: 133(28%). Of aneurysms arising from the internal carotid artery, there were 142(30%) from the posterior communicating artery; internal carotid bifurcation: 29(6%), and anterior choroidal artery: 19(4%). There were 62(13%) giant aneurysms evenly distributed among the middle cerebral, internal carotid bifurcation and anterior cerebral artery. Serious neurological morbidity was observed in 13(3%) patients, who presented a combination of different neurological symptoms including: hemiplegia 3, hemiparesis 6, dysphasia 7, and loss of vision 4. Two patients developed a myocardial infarct and survived. Mortality occurred in 16(3%); these patients died from: a hemispheric infarction 7, severe vasospasm 6, myocardial infarction 2, and pulmonary emboli 1. All aneurysms appeared angiographically obliterated. Vasospasm was observed in 75(16%) patients of which nine were symptomatic, and six of them died. Six major arterial trunks were occluded in the post-operative angiogram, and three patients had occlusion of the internal carotid artery, not identified during surgery. Three of these patients with unexpected occlusions died from a major cerebral infarction, and three had lasting hemipareses and dysphasia. Surgical correction of internal carotid aneurysms can be conducted safely when the anatomical characteristics of the intracranial vessels is preserved, and when these patients are treated with appropriate medical support. 相似文献
35.
L. Lima V. Arce M. J. Diaz J. A. F. Tresguerres J. Devesa 《Clinical endocrinology》1991,35(2):129-135
OBJECTIVE: The aim of this study was to investigate the effect of a single dose of clonidine on the pattern of GH release in response to a 10-hour continuous GRF infusion in normal man. DESIGN: Plasma GH was analysed in samples withdrawn at 20-minute intervals, from 0900 to 1900 h, according to the following protocols: in a control study, a placebo was given at 1000 h; in other experiments, clonidine (300 micrograms, orally) was given at 1000 h, alone or together with a continuous intravenous infusion of GRF 1-29 (0.3 micrograms/kg/h) starting at this time. In another experiment, the continuous infusion of GRF 1-29 was preceded by placebo administration at 1000 h. PATIENTS: Eight normal volunteers (four women and four men), aged 19-24 years were studied. MEASUREMENTS: Plasma GH levels were measured by RIA. Analysis of the pattern of GH secretion was performed using cluster analysis. RESULTS: Clonidine induced a slight but significant increase in plasma GH values, peaking 60 to 120 minutes later; however, no significant changes were observed in indices of total and pulsatile GH release for the whole sampling period in this study. Continuous GRF administration led to increased episodic GH secretion, by augmenting GH peak amplitude, although peak frequency was not modified. An increase in interpulse GH values was also observed during GRF infusion. Pretreatment with clonidine clearly changed the pattern of GH release during GRF infusion: the amount of GH secreted was significantly higher, the number of GH peaks significantly increased, and almost all the GH was secreted within them. CONCLUSIONS: These data concord with our previous demonstration that clonidine disrupts the hypothalamic-somatotroph rhythm by inhibiting the hypothalamic release of somatostatin. Given that clonidine pretreatment induced a more physiological episodic pattern of GRF-induced GH release, the possibility of combining clonidine and GRF therapy for short stature in children is envisaged. 相似文献
36.
A rare case of a patient with Laurence-Moon-Biedl syndrome associated with hypothalamic hamartoma is described. The English-language literature contains no cases of patients with this association. The clinical manifestations of this syndrome, those of hypothalamic hamartomas, and the appearance of the tumors on magnetic resonance images are discussed. 相似文献
37.
38.
C Caruso G Di Lorenzo M A Modica G Candore M R Portelli G Crescimanno A Ingrassia G B Sangiorgi A Salerno 《Mechanisms of ageing and development》1991,59(1-2):27-35
The evidence from several studies indicates that as individuals age, they may display immune dysfunctions, mostly T cell dysfunctions. Recently, a soluble form of the receptor for interleukin-2 (IL-2) (sIL-2R) has been demonstrated in human sera and in vitro stimulated culture supernatants from human T lymphocytes. In the present paper, we report in vitro sIL-2R production from peripheral blood mononuclear cells in elderly subjects. The results show that no difference exists for unstimulated cultures, whereas after mitogen stimulation the elderly subjects showed the lowest values compared with young ones. These findings suggest that sIL-2R may provide a new tool for the study of T lymphocyte dysfunctions in old age. 相似文献
39.
L R Delgado F Nieto A G Diaz R Schwarcz 《International journal of gynaecology and obstetrics》1991,36(4):271-276
The relationship between maternal age and cesarean section in low-risk nulliparas was analysed in 7454 perinatal clinical records selected from eleven databases of Latin American institutions obtained with a comprehensive perinatal information system. The risk of cesarean section in nulliparas between 29 and 49 years of age was found to be three times higher than that corresponding to pregnant women of lesser age. This clearly more aggressive obstetrical conduct could not be explained by the main indications for cesarean section. 相似文献
40.
Jose M. Benitez Del Castillo Ignacio Jimenez-Alfaro Pilar Ortega Alfredo Castillo David Diaz Nicolas Toledano Julian Garcia-Sanchez 《Documenta ophthalmologica. Advances in ophthalmology》1994,86(4):387-393
The possible beneficial effects on the lens and retina which Bendazac Lysine may have in the treatment of adult diabetic patients were investigated. Twenty patients, ranging in age from 54.80 ± 5.86 years old, were studied. The average duration of the diabetes was 11.32 ± 4.10 years. Thirteen patients had background retinopathy. The metabolic controls carried out during the study were satisfactory (HbA1<11%). Bendazac Lysine (500 mg three times a day) was administered for 6 months. Blood-retinal barrier permeability (VPR and VPRt) and lens transmittance (t) were evaluated prior to and 6 months after treatment by fluorophotometry. No statistically significant differences between the pre- and post-treatment values of the retina permeability were observed, however, there was a statistically significant improvement (p<0.05) (initial value: t= 0.813 ± 0.040 and final value: t=0.823 ± 0.037) in the lens transmittance. The authors conclude that Bendazac Lysine has a beneficial effect on the lens in the diabetic adult although no improvement in the permeability of the blood-retinal barrier has been observed. 相似文献