全文获取类型
收费全文 | 73006篇 |
免费 | 6289篇 |
国内免费 | 2526篇 |
专业分类
耳鼻咽喉 | 479篇 |
儿科学 | 1694篇 |
妇产科学 | 858篇 |
基础医学 | 10264篇 |
口腔科学 | 1051篇 |
临床医学 | 6887篇 |
内科学 | 12557篇 |
皮肤病学 | 1288篇 |
神经病学 | 6035篇 |
特种医学 | 1284篇 |
外国民族医学 | 12篇 |
外科学 | 5694篇 |
综合类 | 8016篇 |
现状与发展 | 11篇 |
一般理论 | 1篇 |
预防医学 | 5738篇 |
眼科学 | 1133篇 |
药学 | 11149篇 |
18篇 | |
中国医学 | 3474篇 |
肿瘤学 | 4178篇 |
出版年
2023年 | 1111篇 |
2022年 | 1977篇 |
2021年 | 2689篇 |
2020年 | 2500篇 |
2019年 | 3151篇 |
2018年 | 3016篇 |
2017年 | 2659篇 |
2016年 | 2538篇 |
2015年 | 2724篇 |
2014年 | 4217篇 |
2013年 | 4891篇 |
2012年 | 4152篇 |
2011年 | 4809篇 |
2010年 | 3978篇 |
2009年 | 3352篇 |
2008年 | 3152篇 |
2007年 | 2992篇 |
2006年 | 2572篇 |
2005年 | 2195篇 |
2004年 | 1982篇 |
2003年 | 1826篇 |
2002年 | 1536篇 |
2001年 | 1363篇 |
2000年 | 1042篇 |
1999年 | 1017篇 |
1998年 | 869篇 |
1997年 | 775篇 |
1996年 | 670篇 |
1995年 | 587篇 |
1994年 | 535篇 |
1993年 | 474篇 |
1992年 | 445篇 |
1991年 | 409篇 |
1990年 | 384篇 |
1989年 | 291篇 |
1988年 | 281篇 |
1987年 | 211篇 |
1986年 | 221篇 |
1985年 | 851篇 |
1984年 | 1080篇 |
1983年 | 863篇 |
1982年 | 967篇 |
1981年 | 910篇 |
1980年 | 689篇 |
1979年 | 633篇 |
1978年 | 457篇 |
1977年 | 363篇 |
1976年 | 423篇 |
1975年 | 314篇 |
1973年 | 201篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
61.
Human slow-wave sleep and the cerebral cortex 总被引:1,自引:1,他引:0
Horne J 《Journal of sleep research》1992,1(2):122-124
SUMMARY Recent hypotheses about the roles of human slow-wave sleep (hSWS—delta EEG activity) are appraised. The possible linkage between hSWS and the functions of the prefrontal cortex (PFC) are explored with respect to normal subjects and to disorders involving PFC deficits. 相似文献
62.
土荆皮甲酸的抗生育作用和毒性 总被引:2,自引:0,他引:2
土荆皮甲酸(Pseudolaric acid A),是从金钱松(Pseudolarix kamepferi)的根皮中分离得到的一个新型的二萜类化合物,将其混悬于1%羧甲基纤维素中,经口服给药,对大鼠、仑鼠及狗均可产生明显的抗早孕作用,其抗早孕的有效剂量各为7.5mg/kg,60mg/kg,0.5mg/kg qd×3d,土荆皮甲酸经皮下及阴道给药也能产生明显的抗早孕作用,其对大鼠口服的ED_(50),LD_(50)及95%可信限是14.5(11.7~17.7)mg/kg和219.8(193~250)mg/kg,得治疗指数10.2。狗的亚急性毒性试验表明,土荆皮甲酸对狗的中毒作用主要为呕吐、腹泻、便血等消化道的症状,显微镜下可见胃肠道粘膜及粘膜下组织广泛的出血点,其它器官未见到明显的病理变化。 相似文献
63.
Effect of moderate exercise on salivary immunoglobulin A and infection risk in humans 总被引:3,自引:0,他引:3
Klentrou P Cieslak T MacNeil M Vintinner A Plyley M 《European journal of applied physiology》2002,87(2):153-158
The incidence of upper respiratory tract infections (URTI) and salivary immunoglobulin A concentrations [IgAs] of nine individuals were examined during 12 weeks of moderate exercise training, and compared to ten sedentary controls.
Changes in maximal oxygen uptake were assessed at initial, mid-point and final evaluations (T1–3), while changes in [IgAs] and salivary immunoglobulin concentration-salivary albumin concentration ratio ([IgAs]:[Albs]) were monitored at T1 and T3. During the 12 week period, symptoms of URTI were self-recorded daily. During the period of
training the level of fitness significantly increased (P<0.05) in the exercise group. The number of days recording symptoms of influenza, but not of cold, and total light URTI symptoms was significantly reduced in the exercise group during the last weeks of training. A significant increase in
[IgAs] and in [IgAs]:[Albs] was found in the exercise group after training. Both [IgAs] and [IgAs]:[Albs] were significantly related to the number of days showing symptoms of influenza (P<0.01) and the total number of days of sickness (P<0.05). These data provide quantitative support for the belief that regular, moderate exercise results in an increased [IgAs] at rest and [IgAs]:[Albs], which may contribute to a decreased risk of infection.
Electronic Publication 相似文献
64.
The origins of the projections of the superior colliculus to the dorsal lateral geniculate nucleus and to the pulvinar in Dutch-belted rabbits were investigated using horseradish peroxidase (HRP) methods. Following injections of HRP in the dorsal lateral geniculate nucleus, retrogradely labeled neurons were found in the upper two-thirds of the stratum griseum superficiale of the ipsilateral superior colliculus. Most of the labeled somata were spindle-shaped, and their major axes tended to be perpendicular to the surface of the superior colliculus. In contrast, following injections of the pulvinar, labeled neurons were found in the lower third of the ipsilateral stratum griseum superficiale. In these cases, the labeled somata were larger than those labeled following dorsal lateral geniculate injections and were multipolar in shape. 相似文献
65.
Mehrotra S Singh VK Agarwal SS Maurya R Srimal RC 《Experimental and molecular pathology》2002,72(3):236-242
Extracts of plants have been widely evaluated for possible antiproliferative and anticarcinogenic properties. The antiproliferative activity of ethanolic extract of Boerhaavia diffusa, a plant used in traditional medicine, was evaluated in several cells. It inhibited T cell mitogen phytohemagglutinin and concanavalin A-stimulated proliferation of human peripheral blood mononuclear cells (PBMC). It also inhibited purified protein derivative antigen-stimulated PBMC proliferation and human mixed lymphocyte culture. In addition, B. diffusa extract inhibited the growth of several cell lines of mouse and human origin, such as mouse macrophage cells (RAW 264.7), human macrophage cells (U937), human monocytic cells (THP-1), mouse fibroblast cells (L929), human embryonic kidney cells (HEK293), mouse liver cells (BNLCL.2), African green monkey kidney cells (COS-1), mouse lymphoma cells (EL-4), human erythroleukemic cells (K562), and human T cells (Jurkat). The present study has demonstrated the antiproliferative potential of ethanolic extract of B. diffusa in vitro. 相似文献
66.
M. Parczewski J. Kordek E. Janczewska A. Pisula W. Łojewski Ł. Socha M. Wawrzynowicz-Syczewska M. Bociąga-Jasik A. Szymczak I. Cielniak E. Siwak E. Mularska B. Aksak-Wąs A. Urbańska N. Lübke 《Clinical microbiology and infection》2019,21(4):513.e1-513.e6
Objectives
The aim of the study was to characterize the differences in the frequencies of NS3 and NS5A resistance-associated variants (RAVs) among Polish therapy-naive genotype 1 (G1) hepatitis C virus (HCV)-monoinfected and human immunodeficiency virus (HIV)/HCV-coinfected patients including clustering patterns and association of RAV frequency with liver fibrosis.Methods
NS3/NS5A RAVs were identified by population sequencing in 387 directly acting antiviral treatment-naive G1-infected individuals (54 with genotype 1a (G1a) and 333 with genotype 1b (G1b)). Liver fibrosis was assessed based on histopathology or ultrasound elastography. Phylogenetic clusters were identified using maximum likelihood models. For statistics, chi-squared or two-sided Fisher's exact tests and multivariate logistic regression models were used, as appropriate.Results
NS3 RAVs were found in 33.33% (18/54) for G1a and 2.62% (8/297) for G1b whereas NS5A variants were present in 5.55% (3/54) G1a and 9.31% (31/333) G1b sequences. Variations in NS5A 31 and 93 codon positions were found only in G1b (4.2% (14/333) for L31I/F/M and 5.39% (17/333) for Y93H). NS5A RAVs were more frequent among patients with advanced liver fibrosis (17.17% (17/99) for F3–F4 versus 6.94% (17/245) for F0–F2; p 0.004) or liver cirrhosis (20.34% (12/59) for F4 versus 7.72% (22/285) for F0–F3; p 0.003). Liver cirrhosis (F4) was associated with higher odds ratio of the NS5A RAVs among HCV-infected patients (odds ratio 2.34, 95% CI 1.004–5.291; p 0.049). NS5A RAVs were less frequent among sequences forming clusters and pairs (5.16% (8/155) versus 11.21% (26/232); p 0.039).Conclusions
Presence of NS5A RAVs correlated with progression of liver fibrosis and represents de novo selection of variants rather than transmission of drug resistance. Hence, the presence of NS5A RAVs may be a predictor for a long-lasting HCV infection. 相似文献67.
Flow cytometry immunolabeling, tube agglutination tests, and thin-layer chromatography immunostaining with two different anti-A
monoclonal antibodies (anti-A mAb1 and anti-A mAb2) and one anti-B mAb were used to demonstrate differences in expression
of the A and B antigens among erythrocytes from type A and four different type AB cats. Although the flow cytometric patterns
of reactivity and agglutination scores for erythrocytes from types A and B cats detected with the anti-A and anti-B mAbs were
consistent, reactivity among erythrocytes of different type AB cats was variable. By flow cytometric analysis, 99.9% of type
A erythrocytes, no type B erythrocytes, 2.5–4.0% of erythrocytes from type AB cats 1, 3, and 4, and 60.7% of erythrocytes
from type AB cat 2 had detectable A antigen when anti-A mAb1 was used. In contrast, 86.4% of type A erythrocytes, no type
B erythrocytes, 20.2–38.0% of erythrocytes from type AB cats 1, 3, and 4, and 68.5% of erythrocytes from type AB cat 2 had
detectable A antigen when anti-A mAb2 was used. In addition, 86.9% of type B erythrocytes, no type A erythrocytes, 83.1–96.8%
of erythrocytes from type AB cats 1, 3, and 4, and 73.0% of erythrocytes from type AB cat 2 had detectable B antigen when
the anti-B mAb was used. Agglutination scores of type AB cats were comparable to the percent binding on flow cytometry. Thin-layer
chromatography immunostains confirmed differences in the amount of A antigen between erythrocyte glycolipids of type A and
AB cats and those of type AB cats 1 and 2. These results suggest that at least two different phenotypes exist within the feline
AB blood type, which differ in the amount of A antigen expressed on the erythrocyte surface. 相似文献
68.
Sadataka Inuzuka Takato Ueno Hideo Tateishi Takuji Torimura Michio Sata Kyuichi Tanikawa Masamichi Kojiro 《Pathology international》1994,44(5):391-397
Elevation of the serum angiotensin-converting enzyme (sACE) level and hepatic granulomas were found during a clinical relapse in a 22 year old patient with acute viral hepatitis type A (AVH-A). The serum transaminase level and sACE level remained high for more than 6 months. In the biopsied specimen of the liver, fibrous rings of granulomas composed of collagen types I, III, and V were observed. Furthermore, the localization of ACE was visible in the rough endoplasmic reticulum of epithelioid cells of granulomas in the liver under electron microscopy using the indirect immunoperoxidase method. These results suggest that granuloma cells in the liver caused by hepatitis A may be involved in ACE production. In addition, other diseases associated with the presence of granulomas in the liver, such as lymphoma, cytomegalovirus infection, visceral leishmaniasis, and lupoid hepatitis, were ruled out. However, the hepatic granulomas disappeared with the healing of AVH-A. In this regard, the present case is considered to be one of the very few cases of hepatic sarcoidosis. 相似文献
69.
Progressive multifokale Leukoenzephalopathie bei Wegener'scher Granulomatose unter Therapie mit Cyclosporin A 总被引:1,自引:0,他引:1
J. Ettinger W. Feiden G. Hübner M. Schreiner 《Journal of molecular medicine (Berlin, Germany)》1989,67(4):260-264
Summary A female patient with Wegener's granulomatosis developed severe bone marrow depression after two years treatment with cyclophosphamide. Corticosteroids alone could not sufficiently suppress disease activity, therefore additive therapy with Cyclosporin A was started. Four weeks later the patient developed a central nervous system disorder with affective disturbances and progressive somnolence. However, inspite of intensive diagnostic procedures, no definite diagnosis could be established. After another two months she died. Post-mortem-examination showed progressive multifocal leukoencephalopathy. An association between immunosuppressive therapy and reactivation of JC-Virus is suggested.
Abkürzungsverzeichnis PML Progressive multifokale Leukoenzephalopathie - WG Wegener'sche Granulomatose - CyA Cyclosporin A - (C)CT (Craniale)Computertomographie - NMR Nuclear Magnetic Resonance (Kernspintomographic) - ZNS Zentralnervensystem - AIDS Acquired Immuno-deficiency Syndrome 相似文献
Abkürzungsverzeichnis PML Progressive multifokale Leukoenzephalopathie - WG Wegener'sche Granulomatose - CyA Cyclosporin A - (C)CT (Craniale)Computertomographie - NMR Nuclear Magnetic Resonance (Kernspintomographic) - ZNS Zentralnervensystem - AIDS Acquired Immuno-deficiency Syndrome 相似文献
70.
Peripheral-blood lymphocytes were primed in vitro with the mitogen phytohemagglutinin (PHA) or with allogeneic cells and their memory responses studied following sequential restimulation with either mitogen or alloantigen. Chromosome preparations were made every 12 hours following exposure to the stimulating agents. Cultures were labeled with BUdR for sister-chromatid staining of the chromosomes which provided information about the kinetics of cell growth and rates of sister chromatid exchange. Cultures containing no BUdR were used for the investigation of cell karyotypes after chromosome-banding.Following PHA as well as alloantigen restimulation, an earlier reaction of the responding cells was observed. The peak response after the first stimulation was found at 120 h with allogeneic stimulation and at 60 h with mitogen stimulation. In the second round of stimulation, the peak occurred after 48 h (allogeneic) and 36 h (PHA) and following the third stimulation after 36 h (allogeneic) and 24 h (PHA). The speed of cell growth was decreased following restimulation with either alloantigen and mitogen. In contrast to the allogeneic restimulation, the number of cells responding after PHA restimulation was decreased.No systematic numerical or structural aberration of the karyotype was detected following repeated stimulation with either alloantigen or mitogen. In this sense, the lymphocyte subpopulations selected by repeated stimulation did not differ from the starting material. On the other hand, the sister-chromatid exchange (SCE) frequency was increased following allogeneic restimulation, whereas it remained constant with PHA restimulation. 相似文献