全文获取类型
收费全文 | 7483篇 |
免费 | 427篇 |
国内免费 | 199篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 32篇 |
妇产科学 | 25篇 |
基础医学 | 1312篇 |
口腔科学 | 391篇 |
临床医学 | 588篇 |
内科学 | 873篇 |
皮肤病学 | 17篇 |
神经病学 | 1854篇 |
特种医学 | 141篇 |
外国民族医学 | 1篇 |
外科学 | 470篇 |
综合类 | 742篇 |
现状与发展 | 2篇 |
预防医学 | 340篇 |
眼科学 | 19篇 |
药学 | 936篇 |
11篇 | |
中国医学 | 150篇 |
肿瘤学 | 166篇 |
出版年
2024年 | 12篇 |
2023年 | 85篇 |
2022年 | 149篇 |
2021年 | 218篇 |
2020年 | 216篇 |
2019年 | 184篇 |
2018年 | 162篇 |
2017年 | 168篇 |
2016年 | 170篇 |
2015年 | 227篇 |
2014年 | 378篇 |
2013年 | 390篇 |
2012年 | 341篇 |
2011年 | 410篇 |
2010年 | 347篇 |
2009年 | 343篇 |
2008年 | 378篇 |
2007年 | 318篇 |
2006年 | 356篇 |
2005年 | 273篇 |
2004年 | 245篇 |
2003年 | 241篇 |
2002年 | 204篇 |
2001年 | 163篇 |
2000年 | 151篇 |
1999年 | 118篇 |
1998年 | 162篇 |
1997年 | 155篇 |
1996年 | 134篇 |
1995年 | 107篇 |
1994年 | 119篇 |
1993年 | 106篇 |
1992年 | 100篇 |
1991年 | 112篇 |
1990年 | 82篇 |
1989年 | 79篇 |
1988年 | 67篇 |
1987年 | 82篇 |
1986年 | 75篇 |
1985年 | 95篇 |
1984年 | 79篇 |
1983年 | 48篇 |
1982年 | 63篇 |
1981年 | 38篇 |
1980年 | 32篇 |
1979年 | 24篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 26篇 |
1975年 | 16篇 |
排序方式: 共有8109条查询结果,搜索用时 15 毫秒
1.
《Diagnostic Histopathology》2022,28(3):156-160
Breast core biopsies are a standard component of the triple approach that includes clinical examination, imaging and tissue sampling. Conventional cores, diagnostic vacuum assisted biopsy and vacuum assisted excisions are established methods for sampling and managing breast lesions. It is important to be aware of the potential pitfalls in the technical handling and interpretation of the limited core biopsy samples. Here, we present a clinically oriented, well illustrated overview of the common diagnostic pitfalls based on the author's diagnostic and second opinion practice, emphasize the value of clinicopathological correlation and provide histological tips and clues with useful immunohistochemistry to aid the reporting pathologists in their daily interpretation of breast core biopsies. 相似文献
2.
María del Carmen Azorín Samper Marta Hernandorena Gonzlez Alberto Ibez Arias Sandra Díaz Sierra Marta Bertolo Domínguez Flix Checa Ayet 《The breast journal》2020,26(2):252-254
Breast pseudoaneurysms after a core needle biopsy are a rare complication with a low incidence. However, it is important to be aware of the possibility of complications that require treatment. 相似文献
3.
Over the past 20 years there has been a growing interest in the neural underpinnings of cost/benefit decision-making. Recent studies with animal models have made considerable advances in our understanding of how different prefrontal, striatal, limbic and monoaminergic circuits interact to promote efficient risk/reward decision-making, and how dysfunction in these circuits underlies aberrant decision-making observed in numerous psychiatric disorders. This review will highlight recent findings from studies exploring these questions using a variety of behavioral assays, as well as molecular, pharmacological, neurophysiological, and translational approaches. We begin with a discussion of how neural systems related to decision subcomponents may interact to generate more complex decisions involving risk and uncertainty. This is followed by an overview of interactions between prefrontal-amygdala-dopamine and habenular circuits in regulating choice between certain and uncertain rewards and how different modes of dopamine transmission may contribute to these processes. These data will be compared with results from other studies investigating the contribution of some of these systems to guiding decision-making related to rewards vs. punishment. Lastly, we provide a brief summary of impairments in risk-related decision-making associated with psychiatric disorders, highlighting recent translational studies in laboratory animals. 相似文献
4.
A developmental validation was performed to demonstrate reliability, reproducibility and robustness of the ANDE System with the FlexPlex assay, including an integrated Expert System, across a number of laboratories and buccal sample variations. Previously, the related DNAscan™/ANDE 4C Rapid DNA System using the PowerPlex®16 assay and integrated Expert System Software received NDIS approval in March 2016. The enhanced ANDE instrument, referred to as ANDE 6C, and the accompanying 6-dye, 27-locus STR assay, referred to as FlexPlex, have been developed to be compatible with all widely used global loci, including the expanded set of the CODIS core 20 loci.Six forensic and research laboratories participated in the FlexPlex Rapid DNA developmental validation experiments, testing a total of 2045 swabs, including those obtained from 1387 unique individuals. The goal of this extensive and comprehensive validation was to thoroughly evaluate and document the ANDE System and its internal Expert System to reliably genotype reference buccal swab samples in a manner compliant with the FBI’s Quality Assurance Standards and the NDIS Operational Procedures.The ANDE System, including automated Expert System analysis, generated reproducible and concordant results for buccal swabs when testing various instruments at different laboratories by a number of different operators. When testing a number of non-human DNAs, including oral bacteria, the ANDE System and FlexPlex assay demonstrated limited cross-reactivity. Potential PCR inhibitors were evaluated as part of the validation and no inhibition was detected. Reproducible and concordant profiles were generated from buccal swab samples collected with a limit of detection appropriate for buccal swab collections from arrestees. The precision and resolution of the System met industry standards for detection of microvariants and single base resolution.The integrated Expert System appropriately demonstrated the ability to correctly pass or fail profiles for CODIS upload without human review. During this comprehensive developmental validation, the ANDE System successfully interpreted over 2000 samples tested with over 99.99% concordant alleles. The data package described herein led to the ANDE System with the FlexPlex assay receiving NDIS approval in June 2018. 相似文献
5.
6.
Dino Donataccio Francine Roggen Chantal De Reyck Catherine Verbaandert Monique Bodeus Jan Lerut 《Transplant international》2006,19(1):38-43
The use of livers from anti-hepatitis B core (HBc) positive donors can alleviate donor shortage. Nineteen of 367 (6%) adults receiving anti-HBc positive allografts [three were hepatitis B antigen (HBsAg) negative, hepatitis B antibody (HBsAb) positive; four were HBsAg positive and 12 were not exposed to hepatitis B viral (HBV) infection] were retrospectively reviewed. In HBsAg negative recipients, immunoprophylaxis (IP) was guided by viral serology and immunohistochemistry (IH) of day 0 and day 7 liver biopsies. If IH was negative, IP was stopped. None of three HBsAg negative, HBsAb positive recipients infected; one (replicating) of four HBsAg positive recipients reinfected and seven of eight (87.5%) HBsAg, HBsAb negative recipients, who did not receive long-term IP, infected after a median time of 2 years (range 1-5); one patient died of liver failure. Four HBsAg, HBsAb negative recipients, receiving life-long IP, remained infection free. Anti-HBc positive donor livers must be directed selectively first to HBsAg positive recipients, next to recipients having HBV antibodies and finally to HBV-naive recipients. Identification of both donor and recipient risk factors for HBV infection before transplantation allows indiscriminate use of antiviral prophylaxis. The necessity for IP therapy should be guided by HBV-DNA testing of donor liver tissue and serum. IH of early liver biopsies is an unreliable marker for predicting antiviral treatment requirements. 相似文献
7.
Herman H. Samson Gerald A. Tolliver Miki Haraguchi Peter W. Kalivas 《Brain research bulletin》1991,27(2):267-271
Rats, initiated to self-administer 10% (v/v) ethanol in an operant situation using the sucrose-fading procedure, received bilateral n. accumbens microinjections of d-amphetamine prior to operant sessions. Doses of 4 micrograms, 10 micrograms and 20 micrograms/brain were administered and some animals also received a 4 microgram/brain dose of LY171555. Three different effects were observed: increased, decreased and no change in total session responding. There was no clear relation between injection area in the n. accumbens and type of effect observed. For either an increase or decrease in total session responding, momentary response rates were decreased. Both d-amphetamine and LY171555 produced similar results. The data support the hypothesis that dopamine in the n. accumbens is involved with ethanol reinforced operant responding but in a complex manner. 相似文献
8.
This article reviews the anatomical and functional evidence for ascending pathways from specific brain regions to the PVN and SON which could influence AVP release. The majority of evidence favours the main projection being from a region in the caudal VLM which may coincide with the noradrenergic neurons of the A1 cell group. However, the transmitter(s) involved have yet to be identified, and whether the pathway is excitatory and/or inhibitory remains to be fully resolved.Anatomical and functional evidence is reviewed for descending projections from the SON and PVN to specific brain regions involved in cardiovascular control, and their possible involvement in baroreflex mechanisms is discussed. However, there is little unequivocal evidence that AVP is the main neurotransmitter utilized by descending projections from PVN to NTS and DMX. While, in some situations, circulating endogenous AVP exerts cardiovascular effects, details of its putative influences on baroreflex mechanisms are lacking. 相似文献
9.
10.
Previous studies using the technique of microinjection into brain nuclei indicated that the periaqueductal gray (PAG), nucleus accumbens, habenula and amygdala play an essential role in pain modulation and that these nuclei possibly act through a ‘mesolimbic neural loop‘ to exert an analgesic effect, in which Met-enkephalin (MEK) and β-endorphin (β-EP) have been implicated as the two major opioid peptides involved in antinociception. In the present study performed in rabbits, intracranial microinjection was supplemented with push-pull perfusion and radioimmunoassay to determine whether the release of enkephalins (ENK) and β-EP was increased in these nuclei when the putative neural circuit was activated by morphine administered into one of the nuclei. The results showed: (1) microinjection of morphine into the PAG increased the release of ENK and β-EP in the N. accumbens, and vice versa; (2) microinjection of morphine into the N. accumbens increased the release of ENK and β-EP in the amygdala, and vice versa; (3) morphine microinjected into the PAG caused an increase in the release of ENK and β-EP in the amygdala and vice versa, although the release of ENK in PAG was statistically not significant. These results indicate that PAG, N. accumbens and amygdala are connected in a network served by a positive feedback circuitry. 相似文献