全文获取类型
收费全文 | 1321篇 |
免费 | 83篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 59篇 |
妇产科学 | 32篇 |
基础医学 | 187篇 |
口腔科学 | 24篇 |
临床医学 | 109篇 |
内科学 | 193篇 |
皮肤病学 | 9篇 |
神经病学 | 109篇 |
特种医学 | 53篇 |
外科学 | 324篇 |
综合类 | 3篇 |
预防医学 | 60篇 |
眼科学 | 18篇 |
药学 | 46篇 |
中国医学 | 1篇 |
肿瘤学 | 83篇 |
出版年
2023年 | 12篇 |
2022年 | 13篇 |
2021年 | 36篇 |
2020年 | 23篇 |
2019年 | 40篇 |
2018年 | 41篇 |
2017年 | 45篇 |
2016年 | 54篇 |
2015年 | 40篇 |
2014年 | 48篇 |
2013年 | 57篇 |
2012年 | 74篇 |
2011年 | 72篇 |
2010年 | 50篇 |
2009年 | 55篇 |
2008年 | 62篇 |
2007年 | 71篇 |
2006年 | 58篇 |
2005年 | 49篇 |
2004年 | 55篇 |
2003年 | 53篇 |
2002年 | 42篇 |
2001年 | 34篇 |
2000年 | 24篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 18篇 |
1996年 | 19篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 19篇 |
1991年 | 17篇 |
1990年 | 12篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1960年 | 4篇 |
1956年 | 4篇 |
1942年 | 3篇 |
1941年 | 4篇 |
1936年 | 4篇 |
1932年 | 6篇 |
1930年 | 3篇 |
排序方式: 共有1407条查询结果,搜索用时 15 毫秒
1.
Unilateral asterixis developed in a 56 year old man, 5 months after an infarct in the posterior cerebral artery territory, involving the posterolateral nuclear complex of the thalamus, documented by CT-scan and MRI. Unilateral asterixis in rarely reported in association with thalamic lesions and usually develops as an immediate postictal phenomenon. We discuss possible physiopathological mechanisms explaining the occurrence and the delayed onset of these involuntary movements.
Sommario Un uomo di 56 anni ha sviluppato un'asterixis unilaterale, 5 mesi dopo aver presentato un infarto nel territorio dell'arteria cerebrale posteriore, che coinvolgeva i nuclei postero-laterali del talamo, come evidenziato dalla TC e dalla MRI. Asterixis unilaterali si sviluppano raramente in seguito a lesioni vascolari a livello del talamo e generalmente rappresentano un evento immediatamente successivo all'ictus. Nel caso descritto invece, i movimenti involontari si sono manifestati a notevole distanza di tempo. Gli autori discutono i possibili meccanismi fisiopatologici alla base di questi movimenti involontari e della loro insorgenza a distanza di tempo dall'ictus.相似文献
2.
Luca Oscar Redaelli De Zinis Andrea Bolzoni Cesare Piazza Piero Nicolai 《European archives of oto-rhino-laryngology》2006,263(12):1131-1135
Lymph node (LN) metastases represent the most important negative prognostic factor in squamous cell carcinoma (SCC) of the oral cavity, even though controversies still exist regarding their management. The aim of this study was to retrospectively analyze our experience in surgical management of SCC of the oral cavity with particular focus on the prevalence and localization of lymph nodal metastases and recurrences. The clinical records of 89 consecutive patients treated from 1983 to 2002 by concomitant surgery on both the T and N sites, excluding those undergoing salvage surgery, were reviewed. A total of 119 neck dissections (ND) were performed. Survival outcomes were calculated by the Kaplan–Meier method, while univariate comparisons by the log-rank and non-parametric tests were performed between different groups of patients. Five-year overall and determinate survivals were 50 and 57%, respectively. LN metastases were observed in 52% (56% of these showing extracapsular spread) and their presence strongly correlated with determinate survival (p < 0.0001). The prevalence of clinical and occult nodal disease was not related to the pT status. Neck levels II (59%) and I (56%) were most frequently involved. Metastases to level IV accounted for 15% of positive LN, even though 28% of them turned out to be skip metastases. Five neck recurrences were observed, only one of which was salvaged by surgery. The high prevalence of clinical and occult LN metastases in this setting suggests that ND should be performed on a nearly routine basis, even for lesions with a low-T category and a cN0 neck. Moreover, ND should always encompass level IV due to the possibility of skip metastases, particularly in tumors involving the oral tongue. In patients with a cN+ neck, levels from I to V should be addressed, particularly in the presence of metastases at levels III and IV. 相似文献
3.
E McKiernan K O'Brien N Grebenchtchikov A Geurts-Moespot A M Sieuwerts J W M Martens V Magdolen D Evoy E McDermott J Crown F C G J Sweep M J Duffy 《British journal of cancer》2008,99(10):1644-1650
The protein kinase C (PKC) family of genes encode serine/threonine kinases that regulate proliferation, apoptosis, cell survival and migration. Multiple isoforms of PKC have been described, one of which is PKCδ. Currently, it is unclear whether PKCδ is involved in promoting or inhibiting cancer formation/progression. The aim of this study was therefore to investigate the expression of PKCδ in human breast cancer and relate its levels to multiple parameters of tumour progression. Protein kinase Cδ expression at the mRNA level was measured using real-time PCR (n=208) and at protein level by both immunoblotting (n=94) and ELISA (n=98). Following immunoblotting, two proteins were identified, migrating with molecular masses of 78 and 160 kDa. The 78 kDa protein is likely to be the mature form of PKCδ but the identity of the 160 kDa form is unknown. Levels of both these proteins correlated weakly but significantly with PKCδ concentrations determined by ELISA (for the 78 kDa form, r=0.444, P<0.005, n=91 and for the 160 kDa form, r=0.237, P=0.023, n=91) and with PKCδ mRNA levels (for the 78 kDa form, r=0.351, P=0.001, n=94 and for the 160 kDa form, r=0.216, P=0.037, n=94). Protein kinase Cδ mRNA expression was significantly higher in oestrogen receptor (ER)-positive compared with ER-negative tumours (P=0.007, Mann–Whitney U-test). Increasing concentrations of PKCδ mRNA were associated with reduced overall patient survival (P=0.004). Our results are consistent with a role for PKCδ in breast cancer progression. 相似文献
4.
5.
We defined large striatocapsular infarcts as subcortical softenings of more than 20 mm in diameter involving the territories of the lateral and medial groups of lenticulostriate arteries. The aim of this study of 56 patients was to compare the clinical features and risk factors of these infarcts with those of cortical and lacunar infarcts. On the whole, our data suggest that both the clinical features and risk factors of large striatocapsular infarcts are similar to those of cortical infarcts, but significantly different from those of lacunar infarcts. The clinical manifestations of large striatocapsular infarcts with a maximum diameter of less than 50 mm may sometimes resemble those of lacunar infarcts because neuropsychological disorders are less frequent; however, our study indicates that, even in these cases, cardioembolic sources and artery-to-arteiy embolism are significantly more frequent in large striatocapsular than in lacunar infarcts, thus suggesting a different pathogenesis. 相似文献
6.
7.
Clustering of Y chromosome deletions in subinterval E of interval 6 supports the existence of an oligozoospermia critical region outside the DAZ gene. 总被引:4,自引:0,他引:4 下载免费PDF全文
L Stuppia V Gatta G Mastroprimiano F Pompetti G Calabrese P Guanciali Franchi E Morizio R Mingarelli M Nicolai R Tenaglia L Improta V Sforza S Bisceglia G Palka 《Journal of medical genetics》1997,34(11):881-883
Y chromosome molecular analysis was performed using the STS-PCR technique in 50 patients with oligozoospermia. Microdeletions of interval 6 of the Y chromosome were detected in seven patients, in six of whom subinterval E was affected. All patients retained the RBM1 and DAZ genes, while in one deletion involved the SPGY gene. The size of the deletion was not apparently related to the severity of the disease. These results suggest the presence of an oligozoospermia critical region on the Y chromosome within subinterval E of interval 6. 相似文献
8.
Valery P. Shibaev Nicolai A. Plat Alexander L. Smolyansky Alexander Ya. Voloskov 《Macromolecular chemistry and physics.》1980,181(7):1393-1403
The IR spectra (in the region of 400–3600 cm?1) of comb-like polymers in crystalline, liquid-crystalline, and fluid isotropic phases were studied, and the effect of the chemical structure of the long side chains on the crystalline and liquid-crystalline states were examined. The spectroscopic criteria of phase transitions in comb-like polymers were established and the fragments of the side chains involved in the formation of the liquid-crystalline phase, were determined. 相似文献
9.
10.
Nicolai S.C. van Oers Soo-Jeet Teh Bryan A. Irving Jacqueline Tiong Arthur Weiss Hung-Sia Teh 《Journal of immunological methods》1994,170(2):261-268
The T cell receptor (TCR) comprises an antigen-specific β heterodimer non-covalently associated with the CD3 γδε and TCR ζ subunits. Both the CD3 and TCR ζ subunits are proposed to be responsible for the intracellular signal-transduction events. We report here the production of eight monoclonal antibodies (mAbs) that bind in an ELISA assay to a 113 amino acid synthetic peptide corresponding to the cytoplasmic domain of TCR ζ. Western blot analysis of anti-CD8 precipitates of lysates of transfectants expressing chimeric CD8/ζ constructs encoding increasing COOH-terminal truncations of TCR ζ indicates that four of these mAbs recognized the region of TCR ζ chain comprising the last 29 COOH-terminal residues. Thus, this region of TCR ζ may encode an immunodominant epitope. Furthermore, one of these mAbs, G3, is capable of precipitating both non-phosphorylated and tyrosine phosphorylated TCR ζ. The G3 mAb should be useful for elucidiating the structural and signalling characteristics of the TCR ζ chain. 相似文献