全文获取类型
收费全文 | 11579篇 |
免费 | 814篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 133篇 |
儿科学 | 237篇 |
妇产科学 | 284篇 |
基础医学 | 1700篇 |
口腔科学 | 294篇 |
临床医学 | 1086篇 |
内科学 | 2545篇 |
皮肤病学 | 291篇 |
神经病学 | 1224篇 |
特种医学 | 341篇 |
外科学 | 1579篇 |
综合类 | 81篇 |
一般理论 | 4篇 |
预防医学 | 824篇 |
眼科学 | 240篇 |
药学 | 882篇 |
中国医学 | 20篇 |
肿瘤学 | 649篇 |
出版年
2023年 | 82篇 |
2022年 | 109篇 |
2021年 | 222篇 |
2020年 | 145篇 |
2019年 | 192篇 |
2018年 | 263篇 |
2017年 | 188篇 |
2016年 | 209篇 |
2015年 | 241篇 |
2014年 | 303篇 |
2013年 | 495篇 |
2012年 | 642篇 |
2011年 | 636篇 |
2010年 | 347篇 |
2009年 | 308篇 |
2008年 | 508篇 |
2007年 | 575篇 |
2006年 | 529篇 |
2005年 | 508篇 |
2004年 | 490篇 |
2003年 | 455篇 |
2002年 | 475篇 |
2001年 | 276篇 |
2000年 | 271篇 |
1999年 | 239篇 |
1998年 | 137篇 |
1997年 | 122篇 |
1996年 | 86篇 |
1995年 | 105篇 |
1994年 | 118篇 |
1993年 | 92篇 |
1992年 | 220篇 |
1991年 | 238篇 |
1990年 | 207篇 |
1989年 | 181篇 |
1988年 | 178篇 |
1987年 | 189篇 |
1986年 | 182篇 |
1985年 | 183篇 |
1984年 | 136篇 |
1983年 | 121篇 |
1982年 | 105篇 |
1981年 | 69篇 |
1980年 | 74篇 |
1979年 | 131篇 |
1978年 | 104篇 |
1977年 | 77篇 |
1976年 | 78篇 |
1975年 | 65篇 |
1974年 | 65篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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
2.
3.
4.
5.
Transplanting the Highly Sensitized Patient: The Emory Algorithm 总被引:4,自引:0,他引:4
R. A. Bray J. D. L. Nolen C. Larsen T. Pearson K. A. Newell K. Kokko A. Guasch P. Tso J. B. Mendel H. M. Gebel 《American journal of transplantation》2006,6(10):2307-2315
Renal transplant patients sensitized to HLA antigens comprise nearly one-third of the UNOS wait-list and receive 14% of deceased donor (DD) transplants, a rate half that of unsensitized patients. Between 1999 and 2003, we performed 492 adult renal transplants from DD; 120 patients (approximately 25%) had a panel reactive antibody (PRA) of >30%, with nearly half (n = 58) having a PRA of >80%. Our approach is based upon high-resolution solid-phase HLA antibody analysis to identify class I/II antibodies and a 'virtual crossmatch' to predict compatible donor/recipient combinations. Recipients are excluded from the United Network for Organ Sharing match run if donors possess unacceptable antigens. Thus, when sensitized patients appear on the match run, they have a high probability of a negative final crossmatch. Here, we describe our 5-year experience with this approach. Five-year graft survival ranged from 66% to 70% among unsensitized (n = 272), moderately sensitized (PRA < 30%, n = 100) and highly sensitized (>30% PRA; n = 120) patients, equal to the average national graft survival (65.7%). The application of this approach (the Emory Algorithm) provides a logical and systematic approach to improve the access of sensitized patients to DD organs and promote more equitable allocation to a highly disadvantaged group of patients awaiting renal transplantation. 相似文献
6.
7.
Clinical versus ultrasonographic evaluation of scrotal disorders 总被引:1,自引:0,他引:1
B Kromann-Andersen L B Hansen P N Larsen K Lawetz P Lynge D Lysen S P Nielsen K H Stockholm P Foged 《British journal of urology》1988,61(4):350-353
Clinical and ultrasonographic examinations of scrotal disorders were compared in 166 patients in order to determine their ability to distinguish between those diseases requiring surgery and those requiring clinical follow-up only. Ultrasound examinations were efficient in discriminating between normal and pathological findings. Extra-testicular lesions were readily differentiated from testicular ones. Although both clinical and ultrasonographic examinations had high sensitivity (90%) in detecting testicular cancer, the number of false positive findings was smaller after ultrasound examination. This gave a predictive value of a positive test of 53% after ultrasound examination but only 33% after clinical examination. Ultrasound examination may, therefore, reduce the number of surgical explorations in the scrotum and should be performed in patients with suspected testicular pathology based on history and palpatory findings. 相似文献
8.
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
9.
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
10.
P Rubin S Holm L Friberg P Videbech H S Andersen B B Bendsen N Str?ms? J K Larsen N A Lassen R Hemmingsen 《Archives of general psychiatry》1991,48(11):987-995
To measure prefrontal and subcortical activity during a cognitive task, we examined 19 newly diagnosed schizophrenics and patients with schizophreniform psychosis. Seven healthy volunteers served as controls. The patients were drug naive or had received neuroleptics for a few days only. Cerebral blood flow distribution was depicted by single photon emission computed tomography at rest and during activation with the Wisconsin Card Sorting Test. A significant relative activation deficit in the left inferior-prefrontal region was revealed during the Wisconsin Card Sorting Test in the patient group. Furthermore, the patients had impaired striatal suppression on the left side during the cognitive task. The test performance was significantly impaired in the patients. The inability to reduce striatal activity may be due to a lack of corticostriatal feedback during prefrontal activation. 相似文献