全文获取类型
收费全文 | 9118篇 |
免费 | 683篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 250篇 |
妇产科学 | 55篇 |
基础医学 | 1173篇 |
口腔科学 | 176篇 |
临床医学 | 948篇 |
内科学 | 1894篇 |
皮肤病学 | 147篇 |
神经病学 | 1195篇 |
特种医学 | 682篇 |
外科学 | 1600篇 |
综合类 | 47篇 |
一般理论 | 4篇 |
预防医学 | 437篇 |
眼科学 | 157篇 |
药学 | 420篇 |
中国医学 | 6篇 |
肿瘤学 | 581篇 |
出版年
2024年 | 23篇 |
2023年 | 129篇 |
2022年 | 207篇 |
2021年 | 387篇 |
2020年 | 245篇 |
2019年 | 288篇 |
2018年 | 329篇 |
2017年 | 290篇 |
2016年 | 360篇 |
2015年 | 351篇 |
2014年 | 468篇 |
2013年 | 554篇 |
2012年 | 841篇 |
2011年 | 829篇 |
2010年 | 467篇 |
2009年 | 391篇 |
2008年 | 591篇 |
2007年 | 586篇 |
2006年 | 488篇 |
2005年 | 368篇 |
2004年 | 337篇 |
2003年 | 290篇 |
2002年 | 283篇 |
2001年 | 88篇 |
2000年 | 59篇 |
1999年 | 66篇 |
1998年 | 46篇 |
1997年 | 21篇 |
1996年 | 23篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 18篇 |
1992年 | 39篇 |
1991年 | 28篇 |
1990年 | 32篇 |
1989年 | 27篇 |
1988年 | 26篇 |
1987年 | 26篇 |
1986年 | 15篇 |
1985年 | 20篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1976年 | 11篇 |
1973年 | 10篇 |
1972年 | 12篇 |
1922年 | 14篇 |
排序方式: 共有9845条查询结果,搜索用时 15 毫秒
101.
Keller M Gerbes AL Kulhanek-Heinze S Gerwig T Grutzner U van Rooijen N Vollmar AM Kiemer AK 《World journal of gastroenterology : WJG》2005,11(47):7418-7429
AIM: To determine functional consequences of this activation, whereby we focused on a potential regulation of the hepatocyte cytoskeleton during ischemia and reperfusion. METHODS: For in vivo experiments, animals received ANP (5 μg/kg) intravenously. In a different experimental setting, isolated rat livers were perfused with KH-buffer ±ANP (200 nmol/L)±SB203580 (2 μmol/L). Livers were then kept under ischemic conditions for 24 h, and either transplanted or reperfused. Actin, Hsp27, and phosphorylated Hap27 were determined by Western blotting, p38 MAPK activity by in vitro phosphorylation assay. F-actin distribution was determined by confocal microscopy. RESULTS: We first confirmed that ANP preconditioning leads to an activation of p38 MAPK and observed alterations of the cytoskeleton in hepatocytes of ANP-preconditioned organs. ANP induced an increase of hepatic F-actin after ischemia, which could be prevented by the p38 MAPK inhibitor SB203580 but had no effect on bile flow. After ischemia untreated livers showed a translocation of Hsp27 towards the cytoskeleton and an increase in total Hsp27, whereas ANP preconditioning prohibited translocation but caused an augmentation of Hsp27 phosphorylation. This effect is also mediated via p38 MAPK, since it was abrogated by the p38 MAPK inhibitor SB203580. CONCLUSION: This study reveals that ANP-mediated p38 MAPK activation leads to changes in hepatocyte cytoskeleton involving an elevation of phosphorylated Hsp27 and thereby for the first time shows functional consequences of ANP-induced hepatic p38 MAPK activation. 相似文献
102.
Kiemer AK Gerwig T Gerbes AL Meissner H Bilzer M Vollmar AM 《Journal of hepatology》2003,38(4):490-498
BACKGROUND/AIMS: Pretreatment with atrial natriuretic peptide (ANP) attenuates ischemia-reperfusion injury of livers via cGMP. Heme oxygenase-1 (HO-1) is known as a protective mediator in ischemia-reperfusion injury. The aim of this study was to investigate whether ANP affects the expression of HO-1. METHODS: Rat livers were perfused with KH-buffer with/without ANP or 8-Br-cGMP, kept in UW solution (4 degrees C, 24 h), and reperfused. HO-1 mRNA and protein was determined by Northern and Western blot, in situ hybridization, and immunohistochemistry in livers or isolated liver cells. RESULTS: ANP significantly elevated HO-1 mRNA expression at the end of the preconditioning period and was without effects at the end of ischemia and during reperfusion. 8-Br-cGMP did not affect HO-1 mRNA expression. In situ hybridization as well as immunohistological double-staining revealed that Kupffer cells but not hepatocytes showed HO-1 mRNA and protein expression. Hepatocytes revealed no changes in HO-1 protein whereas Kupffer cells showed a marked increase in HO-1 protein after ANP treatment. Inhibition of HO-1 did not abrogate hepatoprotection conveyed by ANP. CONCLUSION: Our data show the potency of ANP to specifically induce HO-1 in Kupffer cells independently of cGMP. This increased expression of HO-1 is not involved in hepatoprotection conferred by ANP being in line with the knowledge that ANP mediates hepatoprotection via cGMP. 相似文献
103.
Peikert T Finkielman JD Hummel AM McKenney ME Gregorini G Trimarchi M Specks U 《Arthritis and rheumatism》2008,58(5):1546-1551
OBJECTIVE: Antineutrophil cytoplasmic antibodies (ANCA) binding to neutrophil elastase (NE) and proteinase 3 (PR3) are detectable in most patients with cocaine-induced midline destructive lesions (CIMDL), but the pathogenic role and antigen specificity of these antibodies are unknown. This study was undertaken to assess the effects of NE ANCA on the enzymatic activity of NE, to determine whether these antibodies interfere with the physiologic effect of secretory leukoprotease inhibitor (SLPI), and to investigate the antigen specificity of both NE and PR3 ANCA in patients with CIMDL. We also compared the binding of PR3 ANCA in patients with CIMDL with that in patients with Wegener's granulomatosis (WG). METHODS: PR3 ANCA and NE ANCA were detected by capture enzyme-linked immunosorbent assays (ELISAs) and by indirect immunofluorescence. IgG was purified from the patients' sera, and the influence of NE ANCA on the enzymatic activity of NE and on the inhibitory activity of SLPI was investigated by determining the hydrolysis of N-methoxysuccinyl-Ala-Ala-Pro-Val p-nitroanilide by NE. RESULTS: IgG from NE ANCA-positive sera of patients with CIMDL inhibited the enzymatic activity of NE and did not interfere with the activity of SLPI. In contrast to the findings in WG sera, measurement of PR3 ANCA in CIMDL sera showed only fair to moderate concordance between the 2 different capture ELISAs. Cross-inhibition experiments demonstrated that NE ANCA and PR3 ANCA represent distinct autoantibodies in patients with CIMDL. CONCLUSION: The functional effects of NE ANCA on the enzymatic activity of NE or on the activity of SLPI cannot be implicated in the pathogenesis of CIMDL. The autoimmune reaction that targets neutrophil serine proteases in patients with CIMDL is frequently directed against more than one antigen. The ANCA response, including the reactivity of PR3 ANCA, in patients with CIMDL differs from what has been described in patients with WG. 相似文献
104.
Tobias Sieckmann Hatem Elmongy Magnus Ericsson Hasanuzzaman Bhuiyan Mikael Lehtihet Lena Ekstrm 《Drug testing and analysis》2020,12(6):711-719
The detection of low doses of recombinant growth hormone is a challenge in antidoping testing. Future testing may lead toward the longitudinal monitoring of IGF‐I and P‐III‐NP in an endocrine module. Additional biomarkers, for example vitamin D binding protein, alpha‐HS‐glycoprotein, fibronectin 1, and decorin have been identified in different omics studies. This was a longitudinal study of the usefulness of these putative biomarkers in relation to 2 weeks administration of low doses of recombinant growth hormone in healthy male volunteers. Moreover, the hematological parameters included in the athlete biological passport were studied as well as the serum concentration of testosterone and dihydrotestosterone. Fibronectin 1 increased by 20% during the treatment period (P ? 0.05), confirming the previous finding. Alpha‐HS‐glycoprotein decreased by 25% up to 3 weeks after treatment (P ? 0.05), contradicting previous results. The addition of fibronectin 1 increased the likelihood of detecting recombinant growth hormone intake based on individual calculated thresholds in some of the participants compared with the GH2000, IGF‐I, and P‐III‐NP. The multiplication of fibronectin 1 concentration by IGF‐I resulted in the most profound (up to 4‐fold) changes. A minor 15% increase (P = 0.003) in the reticulocyte percentage was observed, but the changes did not lead to any atypical profile based on individual passport thresholds. Vitamin D binding protein, decorin, testosterone, and dihydrotestosterone were not affected by growth hormone. Dihydrotestosterone sulfate was negatively correlated with IGF‐I at baseline (R = –0.50, P = 0.003) and post dose (R = –0.59, P = 0.01). In conclusion, fibronectin 1 was verified as a promising future biomarker for detecting low doses of recombinant growth hormone. 相似文献
105.
Franziska Gaunitz Tobias Kieliba Mario Thevis Katja Mercer‐Chalmers‐Bender 《Drug testing and analysis》2020,12(1):27-40
This article comprises the development and validation of a protocol for the qualitative analysis of 61 phase I synthetic cannabinoid metabolites in urine originating from 29 synthetic cannabinoids, combining solid‐phase extraction (SPE) utilizing a reversed phase silica‐based sorbent (phenyl) with liquid chromatography–tandem mass spectrometry (LC?MS/MS). Validation was performed according to the guidelines of the German Society of Toxicological and Forensic Chemistry. Sufficient chromatographic separation was achieved within a total runtime of 12.3 minutes. Validation included specificity and selectivity, limit of detection (LOD), recovery and matrix effects, as well as auto‐sampler stability of processed urine samples. LOD ranged between 0.025 ng/mL and 0.5 ng/mL in urine. Recovery ranged between 43% and 97%, with only two analytes exhibiting recoveries below 50%. However, for those two analytes, the LODs were 0.05 ng/mL in urine. In addition, matrix effects between 81% and 185% were determined, whereby matrix effects over 125% were observed for 10 non‐first‐generation synthetic cannabinoid metabolites. The developed method enables the rapid and sensitive detection of synthetic cannabinoid metabolites in urine, complementing the spectrum of existing analytical tools in forensic case work. Finally, application to 61 urine samples from both routine and autopsy case work yielded one urine sample that tested positive for ADB‐PINACA N‐pentanoic acid. 相似文献
106.
107.
108.
Lyons Naomi Strasser Alexa Beitz Bernard Teismann Tobias Ostermann Thomas Anderle Laura Michalak Johannes 《Cognitive therapy and research》2021,45(3):508-516
Cognitive Therapy and Research - Emotions play a central role in mental disorder and especially in depression. They are sensed in the body, and it has recently been shown in healthy participants... 相似文献
109.
110.
Tobias Straub Oliver Schweier Michael Bruns Falk Nimmerjahn Ari Waisman Hanspeter Pircher 《European journal of immunology》2013,43(9):2338-2348
CD8+ T cells have an essential role in controlling lymphocytic choriomeningitis virus (LCMV) infection in mice. Here, we examined the contribution of humoral immunity, including nonneutralizing antibodies (Abs), in this infection induced by low virus inoculation doses. Mice with impaired humoral immunity readily terminated infection with the slowly replicating LCMV strain Armstrong but showed delayed virus elimination after inoculation with the faster replicating LCMV strain WE and failed to clear the rapidly replicating LCMV strain Docile, which is in contrast to the results obtained with wild‐type mice. Thus, the requirement for adaptive humoral immunity to control the infection was dependent on the replication speed of the LCMV strains used. Ab transfers further showed that LCMV‐specific IgG Abs isolated from LCMV immune serum accelerated virus elimination. These Abs were mainly directed against the viral nucleoprotein (NP) and completely lacked virus neutralizing activity. Moreover, mAbs specific for the LCMV NP were also able to decrease viral titers after transfer into infected hosts. Intriguingly, neither C3 nor Fcγ receptors were required for the antiviral activity of the transferred Abs. In conclusion, our study suggests that rapidly generated nonneutralizing Abs specific for the viral NP speed up virus elimination and thereby may counteract T‐cell exhaustion. 相似文献