全文获取类型
收费全文 | 44458篇 |
免费 | 7371篇 |
国内免费 | 202篇 |
专业分类
耳鼻咽喉 | 1012篇 |
儿科学 | 1426篇 |
妇产科学 | 1064篇 |
基础医学 | 2697篇 |
口腔科学 | 3163篇 |
临床医学 | 6263篇 |
内科学 | 10150篇 |
皮肤病学 | 994篇 |
神经病学 | 3060篇 |
特种医学 | 2078篇 |
外国民族医学 | 1篇 |
外科学 | 8236篇 |
综合类 | 379篇 |
现状与发展 | 12篇 |
一般理论 | 15篇 |
预防医学 | 3823篇 |
眼科学 | 1138篇 |
药学 | 2215篇 |
中国医学 | 44篇 |
肿瘤学 | 4261篇 |
出版年
2024年 | 178篇 |
2023年 | 1293篇 |
2022年 | 746篇 |
2021年 | 1597篇 |
2020年 | 1652篇 |
2019年 | 1277篇 |
2018年 | 2235篇 |
2017年 | 1877篇 |
2016年 | 2131篇 |
2015年 | 2208篇 |
2014年 | 2933篇 |
2013年 | 3510篇 |
2012年 | 2473篇 |
2011年 | 2409篇 |
2010年 | 2204篇 |
2009年 | 2732篇 |
2008年 | 1992篇 |
2007年 | 1674篇 |
2006年 | 1745篇 |
2005年 | 1413篇 |
2004年 | 1186篇 |
2003年 | 1024篇 |
2002年 | 885篇 |
2001年 | 961篇 |
2000年 | 817篇 |
1999年 | 862篇 |
1998年 | 655篇 |
1997年 | 615篇 |
1996年 | 668篇 |
1995年 | 528篇 |
1994年 | 412篇 |
1993年 | 355篇 |
1992年 | 438篇 |
1991年 | 436篇 |
1990年 | 383篇 |
1989年 | 352篇 |
1988年 | 330篇 |
1987年 | 340篇 |
1986年 | 290篇 |
1985年 | 269篇 |
1984年 | 186篇 |
1983年 | 215篇 |
1982年 | 167篇 |
1981年 | 137篇 |
1980年 | 103篇 |
1979年 | 161篇 |
1978年 | 109篇 |
1977年 | 112篇 |
1974年 | 89篇 |
1973年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
Using fura-2 loaded neural tumour cells, SK-N-SH, we demonstrate that receptor-mediated activation of phosphoinositide hydrolysis not only causes the release of Ca2+ from intracellular stores but also causes a concomitant influx of extracellular Ca2+. Thapsigargin (TG), a sesquiterpene lactone, causes a sustained elevation of intracellular Ca2+ and depletion of the inositol 1, 4, 5-trisphosphate-sensitive intracellular Ca2+ stores. In the absence of extracellular Ca2+, the increase in intracellular Ca2+ concentration ([Ca2+]i) was transient, suggesting that thapsigargin activates both intracellular mobilization and the influx of Ca2+ from extracellular space. These results are consistent with the proposal that the depletion of the inositol 1, 4, 5-trisphosphate-sensitive intracellular Ca2+ pool serves as a signal for Ca2+ influx. 相似文献
33.
Brain metastasis is the most common intracranial malignancy in adults. Improvements in modern imaging techniques are detecting previously occult brain metastases, and more effective therapies are extending the survival of patients with invasive cancer who have historically died from extracranial disease before developing brain metastasis. This combination of factors along with increased life expectancy has led to the increased diagnosis of brain metastases. Conventional treatment has been whole brain radiotherapy, which can improve symptoms, but potentially results in neurocognitive deficits. Several strategies to improve the therapeutic ratio are currently under investigation to either enhance the radiation effect, thereby preventing tumor recurrence or progression as well as reducing collateral treatment-related brain injury. In this review article, we discuss new directions in the management of brain metastases, including the role of chemical modifiers, novel systemic agents, and the management and prevention of neurocognitive deficits. 相似文献
34.
Part III of this series of articles, like Part II, reviews the pioneering efforts in the 19th century to improve the quality of artificial teeth. The focus of this article, unlike that of Part II, is specifically modifications in the design of the occlusal anatomy of the 19th century denture teeth, along with the theories of mandibular movement that inspired those modifications. This article concludes the introductory phase of this project, which seeks to unravel the confusing history of the development of (posterior) denture teeth. 相似文献
35.
36.
37.
Phospho-akt expression is associated with a favorable outcome in non-small cell lung cancer. 总被引:3,自引:0,他引:3
Amit Shah William A Swain Donna Richardson John Edwards Duncan J Stewart Catherine M Richardson Daniel E B Swinson Dipika Patel J Louise Jones Kenneth J O'Byrne 《Clinical cancer research》2005,11(8):2930-2936
Akt, a Serine/Threonine protein kinase, mediates growth factor-associated cell survival. Constitutive activation of Akt (phosphorylated Akt, P-Akt) has been observed in several human cancers, including lung cancer and may be associated with poor prognosis and chemotherapy and radiotherapy resistance. The clinical relevance of P-Akt in non-small cell lung cancer (NSCLC) is not well described. In the present study, we examined 82 surgically resected snap-frozen and paraffin-embedded stage I to IIIA NSCLC samples for P-Akt and Akt by Western blotting and for P-Akt by immunohistochemistry. P-Akt protein levels above the median, measured using reproducible semiquantitative band densitometry, correlated with a favorable outcome (P = 0.007). Multivariate analysis identified P-Akt as a significant independent favorable prognostic factor (P = 0.004). Although associated with a favorable prognosis, high P-Akt levels correlated with high tumor grade (P = 0.02). Adenocarcinomas were associated with low P-Akt levels (P = 0.039). Akt was not associated with either outcome or clinicopathologic variables.Cytoplasmic (CP-Akt) and nuclear (NP-Akt) P-Akt tumor cell staining was detected in 96% and 42% of cases, respectively. Both CP-Akt and NP-Akt correlated with well-differentiated tumors (P = 0.008 and 0.017, respectively). NP-Akt also correlated with nodal metastases (P = 0.022) and squamous histology (P = 0.037).These results suggest P-Akt expression is a favorable prognostic factor in NSCLC. Immunolocalization of P-Akt, however, may be relevant as NP-Akt was associated with nodal metastases, a known poor prognostic feature in this disease. P-Akt may be a potential novel therapeutic target for the management of NSCLC. 相似文献
38.
39.
David W. Farley DDS John D. Jones DDS Robert J. Cronin DDS MS 《Journal of prosthodontics》1998,7(2):84-90
Phonetics, esthetics, function, and comfort form the foundation of a successful dental prosthesis. A review of the mechanics of speech as well as common speech problems encountered with a removable maxillary prosthesis are presented. The use of a palatogram to aid the clinician in the assessment and resolution of speech problems associated with a maxillary denture is demonstrated. 相似文献
40.