全文获取类型
收费全文 | 1692篇 |
免费 | 109篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 53篇 |
妇产科学 | 50篇 |
基础医学 | 296篇 |
口腔科学 | 42篇 |
临床医学 | 185篇 |
内科学 | 334篇 |
皮肤病学 | 41篇 |
神经病学 | 161篇 |
特种医学 | 14篇 |
外科学 | 104篇 |
综合类 | 14篇 |
一般理论 | 6篇 |
预防医学 | 190篇 |
眼科学 | 14篇 |
药学 | 114篇 |
中国医学 | 9篇 |
肿瘤学 | 166篇 |
出版年
2024年 | 4篇 |
2023年 | 17篇 |
2022年 | 22篇 |
2021年 | 35篇 |
2020年 | 22篇 |
2019年 | 34篇 |
2018年 | 41篇 |
2017年 | 34篇 |
2016年 | 51篇 |
2015年 | 49篇 |
2014年 | 67篇 |
2013年 | 98篇 |
2012年 | 125篇 |
2011年 | 125篇 |
2010年 | 74篇 |
2009年 | 66篇 |
2008年 | 96篇 |
2007年 | 131篇 |
2006年 | 105篇 |
2005年 | 116篇 |
2004年 | 87篇 |
2003年 | 93篇 |
2002年 | 82篇 |
2001年 | 9篇 |
1999年 | 14篇 |
1998年 | 19篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1987年 | 5篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1968年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有1811条查询结果,搜索用时 0 毫秒
1.
Sigita Gelman rius Sakalauskas Romanas Zykus rius Pranculis Rytis Jurkonis Irma Kuliavienė Arūnas Lukoševičius Limas Kupčinskas Juozas Kupčinskas 《World journal of gastroenterology : WJG》2020,26(38):5836-5848
BACKGROUND Degree of portal hypertension(PH) is the most important prognostic factor for the decompensation of liver cirrhosis and death, therefore adequate care for patients with liver cirrhosis requires timely detection and evaluation of the presence of clinically significant PH(CSPH) and severe PH(SPH). As the most accurate method for the assessment of PH is an invasive direct measurement of hepatic venous pressure gradient(HVPG), the search for non-invasive methods to diagnose these conditions is actively ongoing.AIM To evaluate the feasibility of parameters of endogenously induced displacements and strain of liver to assess degree of PH.METHODS Of 36 patients with liver cirrhosis and measured HVPG were included in the casecontrol study. Endogenous motion of the liver was characterized by derived parameters of region average tissue displacement signal(dantero, dretro, d RMS) and results of endogenous tissue strain imaging using specific radiofrequency signal processing algorithm. Average endogenous strain μ and standard deviation σ of strain were assessed in the regions of interest(ROI)(1 cm × 1 cm and 2 cm × 2 cm in size) and different frequency subbands of endogenous motion(0-10 Hz and 10-20 Hz).RESULTS Four parameters showed statistically significant(P 0.05) correlation with HVPG measurement. The strongest correlation was obtained for the standard deviation of strain(estimated at 0-10 Hz and 2 cm × 2 cm ROI size). Three parameters showed statistically significant differences between patient groups with CSPH, but only dretro showed significant results in SPH analysis. According to ROC analysis area under the curve(AUC) of the σROI[0…10 Hz, 2 cm × 2 cm] parameter reached 0.71(P = 0.036) for the diagnosis of CSPH; with a cut-off value of 1.28 μm/cm providing 73% sensitivity and 70% specificity. AUC for the diagnosis of CSPH for μROI[0…10 Hz, 1 cm × 1 cm] was 0.78(P = 0.0024); with a cut-off value of 3.92 μm/cm providing 73% sensitivity and 80% specificity. Dretro parameter had an AUC of 0.86(P = 0.0001) for the diagnosis of CSPH and 0.84(P = 0.0001) for the diagnosis of SPH. A cut-off value of-132.34 μm yielded 100% sensitivity for both conditions, whereas specificity was 80% and 72% for CSPH and SPH respectively.CONCLUSION The parameters of endogenously induced displacements and strain of the liver correlated with HVPG and might be used for non-invasive diagnosis of PH. 相似文献
2.
3.
Niina S. Jalava Francisco R. Lopez-Picon Tiina-Kaisa Kukko-Lukjanov Irma E. Holopainen 《International journal of developmental neuroscience》2007,25(2):121-131
In this study, we analyzed the spatiotemporal expression patterns of the high-molecular weight (MAP2a and b) and low-molecular weight (MAP2c and d) cytoskeletal microtubule-associated protein-2 (MAP2) isoforms with Western blotting, and the cellular localization of the high-molecular weight MAP2 isoforms with immunocytochemistry in the hippocampi of 1- to 21-day-old rats. Moreover, the temporal profile (from 30 min to 1 week) of MAP2 isoform reactivity to kainic acid-induced status epilepticus was studied in P9 rats. During development, the expression of the high-molecular weight MAP2 isoforms significantly increased, while the low-molecular weight isoforms decreased, the most prominent changes occurring during the second postnatal week. This developmental increase in the high-molecular weight MAP2 expression was also confirmed with immunocytochemistry, which showed increased immunoreactivity, particularly in the molecular layers of the dentate gyrus, and in CA1 and CA3 stratum radiatum. In 9-day-old rats, status epilepticus resulted in a rapid transient increase (about 210%) in the high-molecular weight MAP2 expression, without any effect on the low-molecular weight MAP2. Moreover, disturbed dendritic structure in the CA1 and CA3 stratum radiatum was manifested as formation of varicosities 3h after the kainic acid treatment. The strictly developmentally regulated MAP2 isoform expression suggests different functional roles for these proteins during the postnatal development in the rat hippocampus. Moreover, high-molecular weight MAP2s may play a role in nerve cell survival during cell stress. 相似文献
4.
5.
Miguelina Hernández Héctor Scannone Héctor J Finol Maria E Pineda Irma Fernández Alba M Vargas María E Girón Irma Aguilar Alexis Rodríguez-Acosta 《Experimental and toxicologic pathology》2007,59(2):129-137
This study explored the toxic effects of crotoxin isolated from Crotalus durissus cumanensis venom on the ultrastructure of mice cardiac autonomic nervous system. Mice were intravenously injected with saline (control group) and crotoxin diluted in saline venom (study group) at a dose of 0.107 mg/kg mouse body weight. Samples from the inter-ventricular septum were prepared for electron microscopy after 6 h (G1), 12 h (G2), 24 h (G3) and 48 h (G4). The G1 group showed some cardiomyocyte with pleomorphic mitochondria. Capillary swollen walls, nerve cholinergic endings with depleted acetylcholine vesicles in their interior and other depletions were observed. A space completely lacking in contractile elements was noticed. The G2 group demonstrated a myelinic figure, a subsarcolemic region with few myofibrils and nervous cholinergic terminal with scarce vacuoles in their interior. The G3 group demonstrated a structure with a depleted axonic terminal, mitochondrias varying in size and enhanced electron density. In addition, muscular fibers with myofibrillar structure disorganization, a depleted nervous structure surrounded by a Schwann cell along with an abundance of natriuretic peptides, were seen. An amyelinic terminal with depleted Schwann cell and with scarce vesicles was also observed. Finally, axonic lysis with autophagic vacuoles in their interior and condensed mitochondria was observed in the G4 group. This work describes the first report of ultrastructural damage caused by crotoxin on mice cardiac autonomic nervous system. 相似文献
6.
Impaired hair follicle morphogenesis and cycling with abnormal epidermal differentiation in nackt mice,a cathepsin L-deficient mutation 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Benavides F Starost MF Flores M Gimenez-Conti IB Guénet JL Conti CJ 《The American journal of pathology》2002,161(2):693-703
We previously described an autosomal-recessive mutation named nackt (nkt) exhibiting partial alopecia associated with CD4(+) T-cell deficiency. Also, we recently reported that nkt (now Ctsl(nkt)) comprises a deletion in the cathepsin L (Ctsl) gene. Another recent study reported that Ctsl knockout mice have CD4(+) T-cell deficiency and periodic shedding of hair, which recapitulate the nkt mutation and the old furless (fs) mutation. The current study focuses on the dermatological aspects of the nkt mutation. Careful histological analysis of skin development of homozygous nkt mice revealed a delayed hair follicle morphogenesis and late onset of the first catagen stage. The skin of Ctsl(nkt)/Ctsl(nkt) mice showed mild epidermal hyperplasia and hyperkeratosis, severe hyperplasia of the sebaceous glands, and structural alterations of hair follicles. Epidermal differentiation seems to be affected in nkt skin, with overexpression of involucrin and profilaggrin/filaggrin along with focal areas of keratin 6 expression in the interfollicular epidermis. Severe epidermal hyperplasia, acanthosis, orthokeratosis, and hyperkeratosis were only observed in mice maintained in nonpathogen-free environments. The analysis of Rag2-/- Ctsl(nkt)/Ctsl(nkt) double-mutant mice indicates that the skin defect remains under the absence of T and B cells. This animal model provides in vivo evidence that cysteine protease cathepsin L plays a critical role in hair follicle morphogenesis and cycling, as well as epidermal differentiation. 相似文献
7.
G. Majella de Jong Irma G. H. Timmerman Paul M. G. Emmelkamp 《Journal of behavioral medicine》1996,19(6):529-542
Hitherto, various critics have claimed that the most commonly used measure for daily hassles is confounded with psychological well-being in both content and format. In order to circumvent such contamination, the Survey of Recent Life Experiences (SRLE) was developed by Kohn and MacDonald (1992). In the present study, the SRLE was psychometrically evaluated within a general sample of the Dutch population. Confirmatory factor analysis showed that, with the exception of one item, the original six-factor structure was strongly replicated. For five of six factors, internal consistency reliabilities proved satisfactory. It is argued that the rather low internal consistency reliability of the sixth factor may be improved if additional items are subjoined. In addition, yielded relationships between the SRLE and other variables were in accordance with previous research. It is therefore argued that the results are in support of cross-cultural construct validity of the SRLE. Future use within other Western European societies is recommended. 相似文献
8.
Ariyurek Y Lantinga-van Leeuwen I Spruit L Ravine D Breuning MH Peters DJ 《Human mutation》2004,23(1):99
Since identification of the genes mutated in patients with Autosomal Dominant Polycystic Kidney Disease, PKD1 and PKD2, a large number of different germ line mutations in both genes have been found by conventional PCR-based mutation detection methods. Nevertheless, in approximately 40% of the PKD1 families the disease-causing mutation remains to be elucidated. Complex germ line rearrangements are often not detectable by these standard diagnostic techniques. To detect large deletions in the PKD1 gene we performed Field Inversion Gel Electrophoresis (FIGE) followed by Southern blot analysis with probes selected in the unique and in the reiterated region of this gene. Our analysis revealed 4 deletions in 125 patients, indicating that large deletions in PKD1 are rare. Likely, patients with a deletion that also affects the neighbouring Tuberous Sclerosis Complex 2 (TSC2) gene will be diagnosed as patients with tuberous sclerosis. It was speculated that the exceptional polypyrimidine tract located in intron 21 and the small tract in intron 22, might play a role in the pathogenesis of ADPKD. Since this region is extremely difficult to amplify by PCR, we analysed the 5.8 kb BamHI fragment that contains the polypyrimidine tracts. We did not observe a disease-linked alteration although we detected two different rare variants either in PKD1 or in one of its homologues. 相似文献
9.
Pluijms EM Birkenhäger TK Huijbrechts IP Moleman P 《Journal of affective disorders》2002,69(1-3):93-99
BACKGROUND: Few studies assessing the influence of resistance to antidepressant pharmacotherapy on the response to subsequent electroconvulsive therapy (ECT) are found in the literature. Results are somewhat conflicting and may not be applicable to the population of depressed patients in The Netherlands. The aim of this study is to assess the influence of medication resistance on the short-term response to ECT in a population of severely depressed inpatients in The Netherlands, where ECT is an exceptional treatment, often used as a final treatment option. METHODS: We reviewed the records of 41 consecutive inpatients with major depression according to DSM-III-R criteria and rated each patients' antidepressant pharmacotherapy prior to ECT. We examined the extent to which medication resistance was related to short-term response to ECT. RESULTS: When a reduction of at least 50% on the Hamilton Rating Scale for Depression (HRSD) post-ECT compared to pre-ECT (partial remission) is used as response criterion, medication resistant patients and patients without established medication resistance were equally likely to respond to subsequent ECT. When a post-ECT HRSD score < or = 7 (full remission) is used as response criterion, medication resistant patients were less likely to respond to subsequent ECT (8/29=27.6%) than patients who did not receive adequate antidepressant pharmacotherapy prior to ECT (6/12=50.0%), although the difference in response rate was not statistically significant. LIMITATIONS: This study has a retrospective nature and a relatively small sample size. CONCLUSION: Antidepressant medication resistance does not seem to have an influence on the short-term response to subsequent ECT. However, when the number of patients achieving full remission is concerned, a substantial percentage of antidepressant medication resistant patients respond to ECT, although their response rate was nearly half compared to that of patients without prior adequate treatment with antidepressants. This difference in response rate was not statistically significant. ECT seems to be an effective treatment for both patients with and without prior adequate treatment with antidepressants in this Dutch population. 相似文献
10.
Coral-Vazquez RM Rosas-Vargas H Meza-Espinosa P Mendoza I Huicochea JC Ramon G Salamanca F 《Journal of human genetics》2003,48(2):91-95
The congenital muscular dystrophies (CMDs) are a heterogeneous group of autosomal recessive disorders. Approximately one half of cases diagnosed with classic CMD show primary deficiency of the laminin alpha2 chain of merosin. Complete absence of this protein is usually associated with a severe phenotype characterized by drastic muscle weakness and characteristic changes in white matter in cerebral magnetic resonance imaging (MRI). Here we report an 8-month-old Mexican female infant, from a consanguineous family, with classical CMD. Serum creatine kinase was elevated, muscle biopsy showed dystrophic changes, and there were abnormalities in brain MRI. Immunofluorescence analysis demonstrated the complete absence of laminin alpha2. In contrast, expression of alpha-, beta-, gamma-, and delta-sarcoglycans and dystrophin, all components of the dystrophin-glycoprotein complex, appeared normal. A homozygous C long right arrow T substitution at position 7781 that generated a stop codon in the G domain of the protein was identified by mutation analysis of the laminin alpha2 gene ( LAMA2). Sequence analysis on available DNA samples of the family showed that parents and other relatives were carriers of the mutation. 相似文献