全文获取类型
收费全文 | 37597篇 |
免费 | 1782篇 |
国内免费 | 300篇 |
专业分类
耳鼻咽喉 | 271篇 |
儿科学 | 690篇 |
妇产科学 | 523篇 |
基础医学 | 4948篇 |
口腔科学 | 1076篇 |
临床医学 | 2189篇 |
内科学 | 9257篇 |
皮肤病学 | 880篇 |
神经病学 | 2529篇 |
特种医学 | 1321篇 |
外科学 | 6814篇 |
综合类 | 150篇 |
一般理论 | 1篇 |
预防医学 | 1027篇 |
眼科学 | 735篇 |
药学 | 2133篇 |
中国医学 | 125篇 |
肿瘤学 | 5010篇 |
出版年
2024年 | 29篇 |
2023年 | 210篇 |
2022年 | 557篇 |
2021年 | 905篇 |
2020年 | 467篇 |
2019年 | 673篇 |
2018年 | 879篇 |
2017年 | 670篇 |
2016年 | 805篇 |
2015年 | 825篇 |
2014年 | 1116篇 |
2013年 | 1415篇 |
2012年 | 2305篇 |
2011年 | 2705篇 |
2010年 | 1517篇 |
2009年 | 1249篇 |
2008年 | 2296篇 |
2007年 | 2530篇 |
2006年 | 2373篇 |
2005年 | 2554篇 |
2004年 | 2461篇 |
2003年 | 2455篇 |
2002年 | 2440篇 |
2001年 | 404篇 |
2000年 | 344篇 |
1999年 | 469篇 |
1998年 | 596篇 |
1997年 | 474篇 |
1996年 | 444篇 |
1995年 | 387篇 |
1994年 | 338篇 |
1993年 | 309篇 |
1992年 | 264篇 |
1991年 | 234篇 |
1990年 | 217篇 |
1989年 | 211篇 |
1988年 | 197篇 |
1987年 | 161篇 |
1986年 | 137篇 |
1985年 | 125篇 |
1984年 | 147篇 |
1983年 | 115篇 |
1982年 | 76篇 |
1981年 | 90篇 |
1980年 | 88篇 |
1979年 | 71篇 |
1978年 | 53篇 |
1977年 | 37篇 |
1976年 | 29篇 |
1975年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Yasuo S Watanabe M Tsukada A Takagi T Iigo M Shimada K Ebihara S Yoshimura T 《Endocrinology》2004,145(4):1612-1616
Prolactin (PRL) secretion is regulated by photoperiod in mammals and birds. In mammals, the pars tuberalis (PT) in the pituitary is involved in the regulation of photoperiodic regulation of PRL secretion. In birds, however, hypothalamic vasoactive intestinal peptide is implicated in PRL secretion, and physiological roles of the avian PT remain unknown. In the present study, we show that PRL secretion increases under long days and short days with a night interruptive schedule, both of which also cause gonadal growth in Japanese quail. We have also found Cry1 gene expression in the PT of Japanese quail. Cry1 expression was rhythmic under long and short photoperiods in the PT, and the peak was phase delayed under a lengthened photoperiod. Moreover, expression of Cry1 gene was induced by a light pulse but only when given during the photoinducible phase. In our previous study, we have shown rhythmic Per2 gene expression with a peak in the PT during the early day under various photoperiods. When taken together with the results from the present study, different phase relationships between Per2 and Cry1 in the Japanese quail PT under different photoperiods may decode photoperiodic information and regulate photoperiodic PRL secretion in a manner similar to that of mammals. 相似文献
952.
Sato A Sueoka-Aragane N Saitoh J Komiya K Hisatomi T Tomimasu R Hayashi S Sueoka E 《Journal of cancer research and clinical oncology》2008,134(11):1191-1197
Purpose Development of an early detection marker is one of the most important strategies for improving overall prognosis in lung cancer
patients. We previously reported that hnRNP B1––an RNA binding protein––is overexpressed in lung cancer tissue from the early
stage of cancer, and found that hnRNP B1 mRNA is detectable in the plasma of lung cancer patients using real-time RT-PCR. The purpose of this study was to establish
a quick and simple method for detecting plasma hnRNP B1mRNA for use in screening for lung cancer.
Methods TRC, a homogenous method for fluorescence real-time monitoring of isothermal RNA amplification using intercalation activating
fluorescence DNA probe, was used to detect plasma hnRNP B1 mRNA.
Results The detection limit of hnRNP B1 mRNA by TRC using synthetic control RNA or total RNA derived from a lung cancer cell line was 25 or 8.65 × 102 copies, respectively. Using total RNA extracted from 600 μl of plasma, we detected hnRNP B1 mRNA in 39.1% (9/23) of lung cancer patients, with levels ranging from 1.9 to 19,045.5 copies/100 ng RNA, and in 5.2% (5/97)
of healthy volunteers. Copy numbers were not associated with age, gender, smoking status, or histological type of cancer.
TRC could detect 103 copies of hnRNP B1 mRNA in 10 min.
Conclusion Detection of plasma hnRNP B1 mRNA by TRC is a quick, easy, and non-invasive method suitable for lung cancer screening. 相似文献
953.
954.
Kawayama T Kinoshita T Imaoka H Gauvreau GM O'Byrne PM Aizawa H 《Respirology (Carlton, Vic.)》2008,13(7):1000-1007
Background and objective: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) signalling of regulatory T cells regulates mucosal lymphocyte tolerance and differentiation, and may therefore have a beneficial effect in allergic diseases such as asthma. The aim of this study was to evaluate the effects of fluticasone propionate (FP) on CD4+CD25+ T cell co-expression of CTLA-4 in the sputum of mild asthmatic subjects. Methods: Eleven mild, stable asthmatic subjects completed a double-blind, randomized, cross-over, placebo-controlled study to compare the effects of 14 days 200 µg twice daily FP and placebo. Before and after treatment, airway hyperresponsiveness was measured, and sputum was induced for measurements of CTLA-4+CD4+CD25+ cells, eosinophils and levels of IL-10, IL-13 and transforming growth factor (TGF)-β Results: FP treatment increased co-expression of CTLA-4 on sputum CD4+CD25+ cells from a mean (SEM) of 7.9% (1.8) to 12.7% (3.3) after 14 days treatment (P < 0.05) compared with placebo. FP treatment also significantly increased IL-10 levels, reduced per cent sputum eosinophils, and reduced airway hyperresponsiveness (P < 0.05). There was a significant negative correlation between the change in airway hyperresponsiveness and per cent sputum eosinophils (P < 0.01), but no correlation with changes in CTLA-4+CD4+CD25+ cells (P > 0.05). There was no change in the levels of sputum IL-13 or TGF-β Conclusions: The percentage of airway CTLA-4+CD4+CD25+ cells increased after FP treatment, coincident with improvements in airway inflammation and hyperresponsiveness. Whether improved asthma assessments are related to the increase in CTLA-4+CD4+CD25+ cells and thus improved regulation of T-cell tolerance and differentiation will require a larger sample size to determine. The normalization of CTLA-4+CD4+CD25+ cells in asthma may contribute to the management of this disease. 相似文献
955.
956.
Infection with hepatitis B virus genotype A in Tokyo, Japan during 1976 through 2001 总被引:1,自引:0,他引:1
Kobayashi M Suzuki F Arase Y Akuta N Suzuki Y Hosaka T Saitoh S Kobayashi M Tsubota A Someya T Ikeda K Matsuda M Sato J Kumada H 《Journal of gastroenterology》2004,39(9):844-850
Background Because genotype A of hepatitis B virus (HBV) is not indigenous, there have been only few data on infection with it in Japan.Methods We examined clinical and virological features of the 66 Japanese patients who admitted Toranomon Hospital in Tokyo, Japan, between 1976 and 2001, who were found to have HBV/A infection. HBV genotype A was classified into subtype A (European type) and A (South African type) by phylogenetic analysis of the preS1 and preS2 regions, and the S gene sequences.Results Of the 66 patients infected with HBV/A, 14 (21%) were asymptomatic carriers, 26 (39%) presented with acute hepatitis, 22 (33%) with chronic hepatitis, and 4 (6%) with liver cirrhosis. HBV/A infection persisted for more than 6 months in 5 of the 26 (19%) patients with acute hepatitis. The frequency of acute hepatitis in patients infected with HBV/A was higher after than before 1991 (2/22 [9%] vs 24/44 [55%]; P < 0.0001). The frequency of nucleotide 1858 of T was higher in asymptomatic carriers than in patients with acute hepatitis in whom infection was resolved (5/14 [36%] vs 0/21 [0%]; P = 0.008). Of the 57 patients for whom subtypes of genotype A were determined, subtype A was identified in 53 (93%) and subtype A in only 4 (7%). All patients infected with subtype A were persistently infected with HBV.Conclusions HBV/A infection has become more frequent during recent years, predominantly presenting as acute hepatitis, and subtype A is uncommon in the Tokyo metropolitan area. 相似文献
957.
Yagi Y Sakabe H Kakinoki R Yoshikawa K Inoue T Fujiyama Y Machii T 《[Rinshō ketsueki] The Japanese journal of clinical hematology》2004,45(4):312-315
This case report describes a hairy B cell lymphoproliferative disorder (HBLD) with clinical and hematological features resembling hairy cell leukemia. The patient was a 29-year-old female who demonstrated atypical lymphocytes in her peripheral blood. Physical examination demonstrated splenomegaly, but there were no palpable superficial lymph nodes. Hematological examination showed a leukocyte count of 10.6 x 10(3)/mm3 with 41% atypical lymphocytes. Bone marrow examination showed a normal cellular and an atypical lymphocyte count of 42%. The atypical lymphocytes had microvilli and prominent membranous ruffles on their surfaces. Atypical lymphocytes expressed CD5- CD10- CD11c+ CD19+ CD20+ CD23- CD25- on the surface of the cells on examination by with a fluorescence activated cell sorter. Although these findings were similar to hairy cell leukemia, Japanese variant, the surface marker of the kappa chain and lambda chain was unbiased and studies of immunoglobulin gene rearrangements and expression showed polyclonal proliferation of B cells. Therefore, we diagnosed this patient as having HBLD. Because she did not demonstrate anemia or thrombocytopenia, she is not currently receiving medication. To date, the atypical lymphocyte count has not changed. 相似文献
958.
Fumio Eto Naoki Wada Takashi Maeno Naoyuki Miyake Ikuko Saotome 《Geriatrics & Gerontology International》2004,4(S1):S202-S204
The effect of heel elevation of shoes in Parkinson's disease was analyzed by using two gait measurement systems. The heel elevation brought about some improvement of walking in the patients with Parkinson's disease with shortening of a stride period, a step period and the transition time of the plantar pressure peak from heel contact to toe off. After measurement study of the gait, all the patients answered the best heel height of shoes was higher than that of their casual footwear or the same. This simple treatment method may be also effective for fall prevention in patients with Parkinson's disease, and further investigation with follow-up observations should be necessary to verify the effect. 相似文献
959.
960.
Kometani K Moriyama M Nakashima Y Katayama Y Wang SF Yamasaki S Saito T Hattori M Minato N 《Blood》2008,112(12):4565-4573
We demonstrate that lck promoter-driven conditional expression of transgenic SPA-1, a Rap GTPase-activation protein, causes a profound defect of alphabeta T-cell development at the CD4/CD8 double-negative (DN) stage due to enhanced cell death without affecting gammadelta T-cell development. The effect was specific to the DN stage, because CD4 promoter-driven SPA-1 expression hardly affected T-cell development. Rap1A17, a dominant-negative Rap mutant, interfered with the generation of double-positive (DP) cells from Rag2(-/-) fetal thymocytes in vitro in the presence of anti-CD3epsilon antibody and Notch ligand. Rap GTPases were activated in a DN cell line by the expression of self-oligomerizing CD3 (CD8:CD3epsilon chimera), which substituted autonomous pre-T-cell receptor (TCR) signal, inducing CD69 expression and CD25 down-regulation. Reciprocally, expression of C3G, a Rap guanine nucleotide exchange factor, in both normal and Rag2(-/-) DN cells markedly enhanced Notch-dependent generation and expansion of DP cells without additional anti-CD3epsilon antibody, thus bypassing pre-TCR. Defective alphabeta T-cell development in the conditional SPA-1-transgenic mice was restored completely by introducing a p53(-/-) mutation. These results suggest that endogenous Rap GTPases downstream of pre-TCR play an essential role in rescuing pre-T cells from the p53-mediated checkpoint response, thus allowing Notch-mediated expansion and differentiation. 相似文献