全文获取类型
收费全文 | 5178篇 |
免费 | 259篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 133篇 |
妇产科学 | 229篇 |
基础医学 | 671篇 |
口腔科学 | 277篇 |
临床医学 | 478篇 |
内科学 | 1194篇 |
皮肤病学 | 66篇 |
神经病学 | 575篇 |
特种医学 | 118篇 |
外科学 | 695篇 |
综合类 | 23篇 |
一般理论 | 1篇 |
预防医学 | 208篇 |
眼科学 | 107篇 |
药学 | 260篇 |
中国医学 | 9篇 |
肿瘤学 | 341篇 |
出版年
2023年 | 24篇 |
2022年 | 68篇 |
2021年 | 119篇 |
2020年 | 75篇 |
2019年 | 122篇 |
2018年 | 158篇 |
2017年 | 115篇 |
2016年 | 136篇 |
2015年 | 155篇 |
2014年 | 201篇 |
2013年 | 279篇 |
2012年 | 391篇 |
2011年 | 402篇 |
2010年 | 255篇 |
2009年 | 214篇 |
2008年 | 343篇 |
2007年 | 344篇 |
2006年 | 359篇 |
2005年 | 283篇 |
2004年 | 241篇 |
2003年 | 253篇 |
2002年 | 230篇 |
2001年 | 62篇 |
2000年 | 33篇 |
1999年 | 38篇 |
1998年 | 50篇 |
1997年 | 55篇 |
1996年 | 34篇 |
1995年 | 31篇 |
1994年 | 22篇 |
1993年 | 24篇 |
1992年 | 36篇 |
1991年 | 29篇 |
1990年 | 24篇 |
1989年 | 25篇 |
1988年 | 19篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 17篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 7篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 12篇 |
排序方式: 共有5462条查询结果,搜索用时 0 毫秒
1.
Effects of androgen treatment in impotent men with normal and low levels of free testosterone 总被引:1,自引:0,他引:1
Cesare Carani M.D. Dante Zini M.D. Augusto Baldini M.D. Luciano Della Casa M.D. Anna Ghizzani M.D. Paolo Marrama M.D. 《Archives of sexual behavior》1990,19(3):223-234
The relation between sexual function and serum free testosterone (fT) levels, which represent the active fraction of circulating testosterone, was evaluated. Two groups of impotent male subjects with mild hypogonadism were treated with oral testosterone undecanoate (TU); these men presented with tT/luteinizing hormone (LH) ratio and tT levels at the lower limits of normal. The first group had serum fT below 6.6 ng/ml, considered the lower normal value, according to our laboratory method, whereas the second group had normal fT limits. Administration of TU improved sexual function only in impotent men with low fT levels, but not in subjects with normal fT levels, even though the tT levels and the tT/LH ratio of the two groups were not significantly different. The results of our study suggest the presence of a minimun serum fT threshold, lying near the lower normal range, which determines the male sexual function. Moreover, serum fT levels were a more sensitive index than tT for identifying impotent men who can be successfully treated with androgens. 相似文献
2.
Luca Belli M.D. Alberto Reggiori M.D. Eugenio Cocozza M.D. Luciano Riboldi M.D. 《Skeletal radiology》1992,21(2):107-109
Tropical pyomyositis is an infection of muscles mainly presenting in black people, occurring in the trunk and limbs. At Hoima Hospital, Uganda, 58 patients (30 men and 28 women) with a mean age of 21 years have been investigated by ultrasound; a total of 81 lesions were present. Two different characteristic images were found; abscess was present in 65 cases while 16 patients showed a diffuse infiltration among the muscular fibers. These two different images correspond to the two stages of histologic and clinical progression described by other authors. Ultrasound is useful to demonstrate the progression of pyomyositis and to determine when and where to drain any abscess. 相似文献
3.
Luciano Baresi Fabrizio Consorti Manuele Di Paola Antonio Gargiulo Mauro Pezzè 《Journal of medical systems》1997,21(6):369-388
The quality of health care systems and processes is becoming a prominent problem and more and more efforts are devoted to define methodologies and tools to measure and assure quality of care. New methods are required to optimize health care processes to guarantee high quality standards within (limited) available resources. Resource optimizations able to preserve the quality of treatments require good models of medical processes. This paper presents LEMMA, a new notation to model medical processes. LEMMA provides physicians with intuitive graphical elements to design their models. At the same time a high level timed Petri net corresponding to the designed model is built automatically. In this way, LEMMA models are ascribed formal semantics and can be executed and analyzed automatically. The dual language approach followed in this paper allows physicians to gain all the benefits of formal methods without being proficient in them. Medical users manage simple graphical elements, while Petri nets ensure formality and validation capabilities. In this way LEMMA mixes formal and informal notations, overcoming the problems of both the approaches. The definition of the notation has been supported by the development of an environment to design LEMMA models. The environment, besides letting us experiment with the notation, has been employed to define and analyze real case studies. 相似文献
4.
5.
Antonio Giorgio M.D. Luciano Tarantino Giampiero Francica Nicola Mariniello Antonio Nuzzo Luca del Viscovo Antonio Rotondo 《Cardiovascular and interventional radiology》1996,19(1):27-31
Purpose: To verify the efficacy of ultrasound (US)-guided injection of large amounts of ethanol into large or multiple liver lesions,
in a single session under general anesthesia (one-shot PEI) for percutaneous ablation of hepatic tumors.
Methods: Twenty-nine patients (27 with 51 hepatocellular carcinoma (HCC) nodules on cirrhosis, diameter range 1.0<+>–<+>9.0 cm; two
patients with a single metastasis from the gastroenteric tract, 5.0 and 9.0 cm, respectively, in diameter) were treated with
one-shot PEI.
Results: The total volume of alcohol delivered per patient ranged from 16 to 210 ml. Mean ethanol volume in all patients was 49 ml.
Dynamic computed tomography (CT) examination showed complete necrosis in 41 of 50 lesions. Two patients died of hypovolemic
shock due to massive upper gastrointestinal bleeding, 3 and 7 days, respectively, after the interventional procedure. All
the remaining patients are alive (follow-up 5<+>–<+>14 months) except one who died of liver failure 5 months after. New HCC
nodules occurred in six patients within 6 months and one intralesional relapse was recorded.
Conclusion: In this preliminary experience, one-shot PEI is as effective in inducing liver tumor necrosis as traditional PEI; its advantages
are shorter treatment time and the capability of treating larger and multiple liver lesions. 相似文献
6.
Teresa Coccini Luciano Maestri Francesco S. Robustelli della Cuna L. Bin Lucio G. Costa Luigi Manzo 《Archives of toxicology》1996,70(11):736-741
Styrene is stereoselectively oxidized by cytochrome P450 to its reactive metabolite, styrene oxide. The (R)- and (S)-enantiomers
of styrene oxide can be conjugated with glutathione (GSH) to both (R)- and (S)-diastereoisomers of the specific mercapturic
acids, N-acetyl-S-(1-phenyl-2-hydroxyethyl)-L-cysteine (M1) and N-acetyl-S-(2-phenyl-2-hydroxyethyl)-L-cysteine (M2). Several investigations have indicated different toxic potential of the (R)- and (S)-configurations of styrene
oxide and its GSH- and N-acetyl-conjugates. In this study the mercapturic acid diastereoisomers were measured in the urine
of rats exposed to styrene in combination with ethanol, a good inducer of styrene metabolism. Male Sprague-Dawley rats were
given an isocaloric liquid diet containing ethanol (5% w/v) for 3 weeks. Starting from the 2nd week, the animals were also
exposed to styrene vapours (300 ppm, 6 h/day, 5 days/week) in a dynamic exposure chamber. Both the (R)- and (S)-diastereoisomers
of the M1 and M2 as well as the conventional biomarkers, mandelic acid (MA) and phenylglyoxylic acid (PGA) were measured in
urinary samples. Approximately 30 and 25% reduction of the levels of brain non-protein sulfhydryls (NPS) was observed in the
animals given styrene and ethanol, respectively, while the combined ethanol and styrene treatment resulted in a 60% decrease.
Ethanol consumption also resulted in higher urinary levels of the M1-R, M1-S and M2 metabolites associated with increased
M1-R/S ratio and higher urinary MA excretion compared to animals treated with styrene. These results suggest that the urinary
mercapturic acid diastereoisomers may be used as a noninvasive tool to examine stereoselective patterns of styrene metabolism
in vivo, as well as their alterations caused by ethanol. These compound-specific mercapturic acids may also be valuable indicators
of styrene-induced disorders of GSH homeostasis in nonaccessible organs.
Received: 19 December 1995/Accepted: 10 May 1996 相似文献
7.
Cristofori P Crivellente F Campagnola M Pasini AF Garbin U Rigoni A Tosetti M Turton J Faustinelli I Cominacini L 《International journal of experimental pathology》2004,85(2):105-114
A study has been carried out in the apolipoprotein (apo) E-deficient mouse to investigate the activity of lacidipine (a calcium antagonist with antioxidant properties) in inhibiting the development of atherosclerotic lesions; of particular interest were changes in the susceptibility of low-density lipoproteins (LDL) to oxidation. Mice receiving a Western-type diet to accelerate the development of atherosclerosis were treated orally with vehicle or lacidipine at 3 or 10 mg/kg/day for 8 weeks. Lacidipine treatment (at 3 or 10 mg/kg) had no effect on the plasma lipid profile. However, a significant (P < 0.01) dose-related reduction of 43 and 50% of the aortic lesion area in respect to vehicle-treated mice was observed. Moreover, the resistance of mouse plasma LDL to undergo lipid peroxidation was significantly (P < 0.01) increased in apo E-deficient mice treated with lacidipine. The native LDL-like particle, derived from apo E-deficient mice treated with lacidipine, contained significantly lower concentrations of malonyldialdehyde than the vehicle-treated control group (P < 0.01). After exposure to human umbilical vein endothelial cells, LDL-like particle vitamin E levels (expressed as area under the curve; AUC), were significantly higher (P < 0.01) in both the 3 and 10 mg/kg lacidipine-treated groups, in comparison with the vehicle-treated control animals. We conclude that lacidipine reduced the extent of the atherosclerotic area in hypercholesterolaemic apo E-deficient mice, and that this reduction may be associated with the capacity of the drug to decrease the susceptibility of LDL to oxidation. 相似文献
8.
Caffeine, a non-selective adenosine receptor antagonist, has been suggested as a potential drug to counteract age-related cognitive decline since critical changes in adenosinergic neurotransmission occur with aging. In the present study, olfactory discrimination and short-term social memory of 3, 6, 12 and 18 month-old rats were assessed with the olfactory discrimination and social recognition tasks, respectively. The actions of caffeine (3.0, 10.0 and 30.0 mg/kg, i.p.), the A1 receptor antagonist DPCPX (1.0 and 3.0 mg/kg, i.p.) and the A2A receptor antagonist ZM241385 (0.5 and 1.0 mg/kg, i.p.) in relation to age-related effects on olfactory functions were also studied. The 12 and 18 month-old rats exhibited significantly impaired performance in both models, demonstrating deficits in their odor discrimination and in their ability to recognize a juvenile rat after a short period of time. Acute treatment with caffeine or ZM241385, but not with DPCPX, reversed these age-related olfactory deficits. The present results suggest the participation of adenosine receptors in the control of olfactory functions and confirm the potential of caffeine for the treatment of aged-related cognitive decline. 相似文献
9.
Marucci G Betts CM Liguori L Eusebi V 《Virchows Archiv : an international journal of pathology》2005,446(3):322-324
A case of basaloid carcinoma of the pancreas in a 26-year-old woman is reported. The tumour was constituted by solid nests of relatively uniform neoplastic cells with hyperchromatic nuclei and scant cytoplasm, showing distinct peripheral palisading. There were necrotic areas and deposition of hyaline material, suggesting a basement membrane-like substance. Small foci of clear-cut squamous differentiation were present. Tumour cells were positive for cytokeratin 14 and P63 and negative for neuroendocrine and acinic cell markers. Ultrastructurally, the tumour was constituted by polygonal cells with round nuclei containing clumped chromatin. Occasional tight junctions and keratin filaments were present. Basaloid carcinomas may arise in several sites of the body, the most frequent being the anus and oesophagus, and have poor clinical outcome. The present case appears to be, to the best of our knowledge, the first documented example in the literature of basaloid carcinoma of the pancreas. 相似文献
10.
The interrelationship between mesonephros, adrenal cortex, and gonads was studied in 28- and 31-day old sheep fetuses by means of light microscopy on plastic sections. At these stages, the adrenal cortex is just beginning to develop and the mesonephros is undergoing involution; its regression is accompanied by mobilization of cells from the glomerulus of a peculiar nephron situated in the proximal third of the organ, and referred to as “giant” because of its large size. The mobilized cells egress from this glomerulus organized in trabeculae, some of which reach the cranial extremity of the adrenal cortex while others coalesce into a prominent cellular formation which extends uninterrupted toward and into the developing gonads. In previous studies we have shown that the mesonephric cells which colonize the gonads differentiate into sustentacular and interstitial steroidogenic cells; the presence of an analogous cellular migration from the mesonephros to the adrenal cortex now suggests that also the adrenal cortical cells may be of mesonephric origin. 相似文献