全文获取类型
收费全文 | 6673篇 |
免费 | 580篇 |
国内免费 | 120篇 |
专业分类
耳鼻咽喉 | 68篇 |
儿科学 | 187篇 |
妇产科学 | 264篇 |
基础医学 | 804篇 |
口腔科学 | 92篇 |
临床医学 | 684篇 |
内科学 | 1417篇 |
皮肤病学 | 201篇 |
神经病学 | 463篇 |
特种医学 | 553篇 |
外科学 | 836篇 |
综合类 | 149篇 |
预防医学 | 396篇 |
眼科学 | 107篇 |
药学 | 430篇 |
中国医学 | 29篇 |
肿瘤学 | 693篇 |
出版年
2023年 | 34篇 |
2022年 | 54篇 |
2021年 | 130篇 |
2020年 | 103篇 |
2019年 | 187篇 |
2018年 | 188篇 |
2017年 | 135篇 |
2016年 | 157篇 |
2015年 | 203篇 |
2014年 | 239篇 |
2013年 | 388篇 |
2012年 | 382篇 |
2011年 | 388篇 |
2010年 | 303篇 |
2009年 | 258篇 |
2008年 | 304篇 |
2007年 | 315篇 |
2006年 | 280篇 |
2005年 | 300篇 |
2004年 | 263篇 |
2003年 | 226篇 |
2002年 | 227篇 |
2001年 | 195篇 |
2000年 | 160篇 |
1999年 | 169篇 |
1998年 | 133篇 |
1997年 | 114篇 |
1996年 | 110篇 |
1995年 | 80篇 |
1994年 | 83篇 |
1993年 | 79篇 |
1992年 | 97篇 |
1991年 | 96篇 |
1990年 | 76篇 |
1989年 | 93篇 |
1988年 | 96篇 |
1987年 | 83篇 |
1986年 | 70篇 |
1985年 | 74篇 |
1984年 | 64篇 |
1983年 | 35篇 |
1982年 | 42篇 |
1981年 | 31篇 |
1980年 | 26篇 |
1979年 | 29篇 |
1978年 | 30篇 |
1977年 | 28篇 |
1976年 | 23篇 |
1975年 | 24篇 |
1973年 | 23篇 |
排序方式: 共有7373条查询结果,搜索用时 15 毫秒
1.
Thirty-nine primary surgical cases for correction of congenital aural atresia were reviewed for complications and long-term hearing results. Hearing averages of 25 dB for mild atresia, 40 dB for moderate atresia, and 46 dB for severe atresia were obtained. Serviceable hearing was achieved in 64% of the cases. The two most frequent complications were stenosis and recurrent infections of the cavity and canal skin, with an incidence of 33% and 31%, respectively. Use of split-thickness instead of full-thickness skin graft was associated with fewer complications. The goal of this review is also to share the experience of the senior author in the management of this complex problem. 相似文献
2.
MC Brouard P Chavaz L Borradori 《Journal of the European Academy of Dermatology and Venereology》2004,18(1):89-92
BACKGROUND: Bowel-associated dermatosis-arthritis syndrome denotes the occurrence of diarrhoea with arthritis and skin lesions related to bowel disease with or without bowel bypass. In this condition, the histological finding of cutaneous aseptic neutrophilic cell infiltrate is non-specific and common to a wide spectrum of neutrophilic dermatoses, including pyoderma gangrenosum. OBSERVATION: We describe a 78-year-old woman with fever, abdominal discomfort and arthralgias, who developed grouped pustular lesions on her shins with histologically spongiform pustule formation. Aetiological assessment disclosed diverticular disease with sigmoid stenosis. CONCLUSION: Although clinical and histological features in our case fit the diagnosis of bowel-associated dermatosis-arthritis syndrome, they may also correspond to a pustular variant of pyoderma gangrenosum. Our observation raises the question of the nosological classification of bowel-associated dermatosis-arthritis syndrome within the spectrum of neutrophilic diseases. 相似文献
3.
4.
J C Shih T L Ko M C Lin M K Shyu C N Lee F J Hsieh 《Ultrasound in obstetrics & gynecology》2004,24(2):202-206
The relationship of large and vascularized chorioangiomas to adverse pregnancy outcome is well recognized. We present a patient with a large placental tumor and signs of impending fetal cardiac failure. The angioarchitecture of the tumor depicted by three-dimensional (3D) power Doppler ultrasound enabled us to accurately diagnose a placental chorioangioma. During the follow-up period, quantitative flow data obtained using 3D power Doppler indicated altered hemodynamics in the tumor and concomitant improvement in the condition of the fetus, enabling us to manage the mother conservatively. Spontaneous delivery occurred at 38 weeks without any complications. This report demonstrates the potential value of 3D power Doppler in prenatal diagnosis and monitoring of pregnancies complicated by large, vascularized chorioangioma. 相似文献
5.
Diffusely increased radioactivity in the thoracoabdominal region (lower thorax and/or upper abdomen) occasionally has been observed when performing Tc-99m phosphonate bone studies. To assess the significance of activity in this finding, 1100 bone scintigrams were reviewed and the clinical data and other diagnostic imaging procedures were evaluated in these cases. With the exclusion of Tc-99m sulfur colloid liver-spleen scans 18 patients were found to have mild but diffuse increased radioactivity in the thoracoabdominal region either on the right or left. Clinical findings in these cases with abnormal uptakes were pleural effusions (six cases), hepatic colonic metastases (six cases), splenic metastases from bronchogenic carcinoma (one case), abdominal and peritoneal colonic metastases (one case), a massive metastatic squamous cell carcinoma (from lung) in the right lower chest (one case), and defective radiopharmaceuticals (three cases). Since the defective radiopharmaceuticals contained 5% of hydrolyzed reduced Tc-99m colloid by thin-layer chromatography, each of three patients received approximately 740 mu Ci of Tc-99m sulfur colloid. Factors to be considered in the interpretation of diffuse thoraco-abdominal activity from a bone agent should include splenic or hepatic metastases, a Tc-99m sulfur colloid splenic or hepatic metastases, a Tc-99m sulfur colloid study within the previous 24 hours, pleural effusion, faulty radiopharmaceuticals, and abdominal and peritoneal colonic metastases. 相似文献
6.
Anticonvulsants for poisoning by the organophosphorus compound soman: pharmacological mechanisms. 总被引:4,自引:0,他引:4
Exposure to high doses of organophosphorus nerve agents such as soman, even with carbamate pretreatment, produces a variety of toxic cholinergic signs, including secretions, convulsions and death. Evidence suggests that soman-induced convulsions may be associated with postexposure brain neuropathology. The purpose of this study was to investigate the pharmacologic mechanism of action of soman-induced convulsions and of anticonvulsant drugs. Various classes of compounds were evaluated for their efficacy in preventing soman-induced convulsions in rats pretreated with the oxime HI-6 to increase survival time, along with various doses of the test compounds (IM) either in the absence or presence of atropine sulfate (16 mg/kg, IM) 30 minutes prior to a soman challenge dose (180 micrograms/kg, SC; equivalent to 1.6 x LD50) that produced 100% convulsions. Without atropine sulfate, only tertiary anticholinergics (scopolamine, trihexyphenidyl, biperiden, benactyzine, benztropine, azaprophen and aprophen), caramiphen, carbetapentane and MK-801 were effective anticonvulsants. In the presence of atropine sulfate, the benzodiazepines (diazepam, midazolam, clonazepam, loprazolam and alprazolam), mecamylamine, flunarizine, diphenylhydantoin, clonidine, CGS 19755 and Organon 6370 studied were effective. We have examined the possibility that diazepam may exert some of its anticonvulsant effects through cholinergic mechanisms and found that a reduced release of ACh into synapses after diazepam and atropine treatment may account for diazepam's anticonvulsant activity against soman. We also found that at anticonvulsant doses biperiden and trihexyphenidyl each significantly reversed the effects of soman on striatal levels of DOPAC and HVA, the metabolites of dopamine, and have concluded that in addition to actions on muscarinic receptors, the anticonvulsant effects of these anticholinergics in soman poisoning may be partially related to their actions on the striatal dopaminergic system. These findings allow us to postulate that central muscarinic cholinergic mechanisms are primarily involved in eliciting the convulsions following exposure to soman and that subsequent recruitment of other excitatory neurotransmitter systems and loss of inhibitory control may be responsible for sustaining the convulsions and for producing the subsequent brain damage. Future studies to confirm these neuropharmacological mechanisms are proposed. 相似文献
7.
W J Shih P A Domstad F H DeLand R Beihn V Stipp 《European journal of nuclear medicine》1986,12(5-6):299-301
Cholescintigraphy of cholelithiasis has been reported as a defect or photon deficient area in the gallbladder. We present the case of a patient with gallstones whose cholescintigraphic study showed a sequential evaluation of the scan appearance from a defect, to a septation, a hole, and finally a filled-in appearance. Cholescintigrams and histopathologic findings after cholecystectomy of another 22 patients with cholelithiasis were also retrospectively reviewed. The results of the study concluded that: cholelithiasis is rarely demonstrated by cholescintigraphy and nonvisualization of the gallbladder may be due to acute or chronic cholecystitis associated with cholelithiasis. 相似文献
8.
Purpose. To obtained rate constants from weight-averaged (Mw) or z-averaged (Mz) molecular weights for polymers of Schule-Flory distribution and undergoing random scission. These constants were compared with those obtained by parallel 1HNMR studies.
Methods. The hydrolysis of two poly(ortho ester)s were followed by 1HNMR and gel permeation chromatography (GPC).
Results. Equations to convert number-averaged (Mn), Mw and Mz into fraction of backbone remaining (fc) were derived. First-order hydrolytic rate constants of two poly(ortho ester)s; DETOSU-HD and DETOSU-CDM were calculated using these relationships. The rate constants calculated from 1HNMR, Mz and Mw were 0.215, 0.218 and 0.182 hr–1, respectively, for DETOSU-CDM and 0.152, 0.086 and 0.038 hr–l for DETOSU-HD. The large discrepancy in the rates determined by 1HNMR and GPC in the latter case was attributed to that the detector response (refractive index) of the monomers was lower than that of the high molecular weight polymer. The difference is small in the case of DETOSU-CDM, and the rates calculated from GPC data were comparable or nearly identical to that obtained from 1HNMR data.
Conclusions. Although GPC can yield rapid and valuable kinetic data for the degradation of biodegradable polymers, the system, however, must be carefully calibrated to account for the variations in Mark-Houwink coefficients and in the response of the mass detector between the high and low MW polymers. 相似文献
9.
10.
Advanced primary breast cancer: assessment at mammography of response to induction chemotherapy 总被引:2,自引:0,他引:2
The response to induction chemotherapy is an important prognostic factor in patients with nonmetastatic, locally advanced breast carcinomas. Assessment at mammography of the response of 60 breast cancers in 59 women was performed between 1974 and 1986. Responses were excellent in 13 tumors, moderate in 34, and poor in 13 (excellent moderate = 78%). Assessment of response of discrete masses in a fatty breast was easiest; assessment of response of tumor areas that were poorly defined-such as a focal area of architectural distortion or mass in dense breast parenchyma-was more difficult. Of 17 patients with excellent pathologic responses-that is, minimal or no residual tumor-15 (88%) had complete responses (no residual tumor) as determined with mammography, physical examination, or both. Mammography provides information complementary to physical examination and is essential in the accurate assessment of the response to chemotherapy of locally advanced breast cancer. 相似文献