全文获取类型
收费全文 | 11575篇 |
免费 | 787篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 159篇 |
儿科学 | 247篇 |
妇产科学 | 195篇 |
基础医学 | 1776篇 |
口腔科学 | 264篇 |
临床医学 | 1053篇 |
内科学 | 3099篇 |
皮肤病学 | 185篇 |
神经病学 | 1134篇 |
特种医学 | 343篇 |
外科学 | 1410篇 |
综合类 | 65篇 |
一般理论 | 5篇 |
预防医学 | 820篇 |
眼科学 | 93篇 |
药学 | 871篇 |
中国医学 | 11篇 |
肿瘤学 | 649篇 |
出版年
2023年 | 75篇 |
2022年 | 86篇 |
2021年 | 199篇 |
2020年 | 146篇 |
2019年 | 186篇 |
2018年 | 220篇 |
2017年 | 190篇 |
2016年 | 249篇 |
2015年 | 275篇 |
2014年 | 324篇 |
2013年 | 477篇 |
2012年 | 631篇 |
2011年 | 649篇 |
2010年 | 357篇 |
2009年 | 356篇 |
2008年 | 581篇 |
2007年 | 533篇 |
2006年 | 547篇 |
2005年 | 551篇 |
2004年 | 477篇 |
2003年 | 446篇 |
2002年 | 424篇 |
2001年 | 295篇 |
2000年 | 232篇 |
1999年 | 251篇 |
1998年 | 133篇 |
1997年 | 105篇 |
1996年 | 112篇 |
1995年 | 100篇 |
1994年 | 114篇 |
1993年 | 98篇 |
1992年 | 212篇 |
1991年 | 227篇 |
1990年 | 227篇 |
1989年 | 223篇 |
1988年 | 179篇 |
1987年 | 174篇 |
1986年 | 192篇 |
1985年 | 186篇 |
1984年 | 118篇 |
1983年 | 139篇 |
1982年 | 113篇 |
1981年 | 64篇 |
1980年 | 63篇 |
1979年 | 111篇 |
1978年 | 100篇 |
1977年 | 67篇 |
1975年 | 60篇 |
1974年 | 65篇 |
1973年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Ole Rogeberg 《Addiction (Abingdon, England)》2020,115(1):184-187
The Theory of Rational Addictions, by Gary Becker & Kevin Murphy (1988), was a rational choice model that became a standard tool for economists modeling addictive behavior. The approach differs from other theories of addiction by modeling addictive behavior as the gradual implementation of a rational, forward‐looking plan, where consumption at any point in time is partly motivated by the immediate payoff of consumption and partly by the effects this consumption has on the individual in the future. This makes addictive behavior a subset of rational behavior, requiring no more specific government policies or attention than any other consumption choice. Later work by economists extended the theory in different ways, allowing it to match an increasing number of consumption patterns, and searched for ways to test the forward‐looking assumption in different types of market data. While the work was successful as a contribution to rational choice theory, with possible statistical applications, there are several reasons to dismiss its usefulness as an explanation of real‐world addictive behavior and its ability to assess the welfare effects of addictions. 相似文献
3.
4.
Anders Elm Pedersen Esben Gjerløff Wedebye Schmidt Jesper Freddie Sørensen Carsten Faber Boye Schnack Nielsen Kim Holmstrøm Silje Haukali Omland Peter Tougaard Søren Skov Bo Bang 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2015,123(7):547-555
TL1A is a TNF‐like cytokine which has been shown to co‐stimulate TH1 and TH17 responses during chronic inflammation. The expression of this novel cytokine has been investigated in inflammatory disorders like rheumatoid arthritis and inflammatory bowel disease, but little is known about expression and induction in psoriasis. Indeed, the pathogenesis in psoriasis is still not fully understood and it is speculated that cytokines other than TNF‐α are important in subsets of patients. Also, for patients with severe disease that are treated with systemic anti‐TNF‐α blockade, novel candidates to be used as disease and response biomarkers are of high interest. Here, we demonstrate TL1A expression in biopsies from psoriatic lesions. Also, we investigated spontaneous and induced TL1A secretion from PBMCs and blood levels from a cohort of psoriasis patients. Here, increased spontaneous secretion from PBMCs was observed as compared to healthy controls and a small subset of patients had highly elevated TL1A in the blood. Interestingly, activation of PBMCs with various cytokines showed a decreased sensitivity for TL1A activation in psoriasis patients compared to healthy controls.TL1A levels in blood and biopsies could not be correlated with disease activity with this patient cohort. Thus, additional large‐scale studies are warranted to investigate TL1A as a biomarker. 相似文献
5.
6.
7.
8.
9.
Eigil Samset Anne Talsma Marius Kintel Ole Jakob Elle Lars Aurdal Henry Hirschberg Erik Fosse 《Computer aided surgery》2002,7(4):187-196
Intraoperative MRI has recently entered the operating room as a new imaging modality. Customized visualization systems might further facilitate the use of this imaging technology. A visualization system for use in the interventional MRI has been developed, providing a virtual environment for surgical navigation using real-time images and for controlling the scanner. The visualization system has customized features for certain clinical applications. A training and testing facility has also been established. The introduction of the visualization system in the interventional MRI overcame several ambiguities and inconsistencies that were previously present, and resulted in a more transparent man-machine interface approach. A pilot study using the software to place cryoprobes in an animal liver showed promising results. Augmentation of real-time MR images with 3D rendering and customized navigation features opens new possibilities in intraoperative MRI. The described system can also be extended to other intraoperative imaging modalities. 相似文献
10.
Birger Ragnarson Göran Örnung Ole P Ottersen Gunnar Grant Brun Ulfhake 《Journal of neuroscience methods》1998,80(2):42-136
Choleragenoid (cholera toxin B-fragment; CTB) is an anterograde, retrograde and transganglionic neuronal tracer. We describe a method for detecting CTB-labeled neuronal cell bodies, neurites and boutons at the ultrastructural level, using postembedding immunogold techniques on freeze-substituted Lowicryl HM20™ embedded nervous tissue. Primary afferents and motoneurons were labeled by injection of CTB in the dorsal ramus of the C2 spinal nerve of the rat. Following fixation with paraformaldehyde (4%) and glutaraldehyde (0.25%), tissue sections from the spinal cord C2 segment were freeze-substituted and embedded in Lowicryl HM20™ and subsequently processed with postembedding immunocytochemistry for CTB and glutamate. Immunogold particles indicating CTB immunoreactivity were found over primary afferents and motoneurons. In primary afferents in the central cervical nucleus (CCN) and motor nuclei, immunogold labeling was seen in boutons over vesicle-containing axoplasm and to a lesser extent over axoplasm devoid of vesicles, but not over mitochondria or axolemma. In motoneurons, immunogold particles were seen over the Golgi apparatus in the soma and over lysosomes in both soma and dendrites. Quantification of glutamate-like immunoreactivity in 20 CTB-labeled and 20 CTB-negative boutons in the neuropil was found similar, indicating that CTB does not interfere with the immunocytochemical detection of neuronal epitopes such as the transmitter substance glutamate. 相似文献