全文获取类型
收费全文 | 2966篇 |
免费 | 163篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 76篇 |
妇产科学 | 35篇 |
基础医学 | 379篇 |
口腔科学 | 35篇 |
临床医学 | 235篇 |
内科学 | 648篇 |
皮肤病学 | 56篇 |
神经病学 | 181篇 |
特种医学 | 50篇 |
外科学 | 490篇 |
综合类 | 51篇 |
一般理论 | 1篇 |
预防医学 | 307篇 |
眼科学 | 48篇 |
药学 | 324篇 |
中国医学 | 25篇 |
肿瘤学 | 179篇 |
出版年
2023年 | 34篇 |
2022年 | 87篇 |
2021年 | 118篇 |
2020年 | 54篇 |
2019年 | 90篇 |
2018年 | 91篇 |
2017年 | 48篇 |
2016年 | 77篇 |
2015年 | 83篇 |
2014年 | 114篇 |
2013年 | 148篇 |
2012年 | 197篇 |
2011年 | 222篇 |
2010年 | 106篇 |
2009年 | 105篇 |
2008年 | 154篇 |
2007年 | 169篇 |
2006年 | 158篇 |
2005年 | 160篇 |
2004年 | 124篇 |
2003年 | 119篇 |
2002年 | 96篇 |
2001年 | 44篇 |
2000年 | 51篇 |
1999年 | 46篇 |
1998年 | 15篇 |
1997年 | 19篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 31篇 |
1991年 | 31篇 |
1990年 | 24篇 |
1989年 | 28篇 |
1988年 | 32篇 |
1987年 | 14篇 |
1986年 | 21篇 |
1985年 | 24篇 |
1984年 | 20篇 |
1983年 | 18篇 |
1981年 | 12篇 |
1979年 | 18篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 10篇 |
1975年 | 10篇 |
1974年 | 12篇 |
1973年 | 9篇 |
1972年 | 6篇 |
排序方式: 共有3149条查询结果,搜索用时 15 毫秒
81.
Samia Shawky 《Avian pathology》2000,29(6):609-616
Duck enteritis virus (DEV), a herpesvirus, has been shown to cause lymphoid organ atrophy and immunosuppression in white Pekin ducklings. The cells that support virus replication and could be important for immunosuppression were identified in this study. Lymphoid organs of white Pekin ducks infected at 2 weeks of age were collected at 3, 6, 8 and 10 days post-inoculation (d.p.i.). Frozen sections were double-stained for DEV-infected (DEV+) and epithelial cells, DEV+ and CD3+ cells or DEV+ and B cells. DEV antigen was detected in the spleen, thymus and bursa for 3, 6 and 8 d.p.i., respectively. DEV antigen was demonstrated in epithelial cells of all examined lymphoid organs. B cells were irreversibly depleted from bursa; however, the depletion in the spleen was only for 8 d.p.i. Depletion of CD3+ cells was only observed in the thymus. These data show that the target cells for DEV are epithelial and B cells. 相似文献
82.
Surbhi Shah M.B.B.S. Khaliqur Rahman M.D. Farhan Siddiqui M.D. Kafil Akhtar M.D. Sufian Zaheer M.D. Rana Sherwani M.D. 《Diagnostic cytopathology》2009,37(6):397-401
This study was conducted to evaluate the role of sediment cytology of biopsy specimen fixatives, which is usually discarded, in early diagnosis of bone lesions. Cytological smears prepared from sediments of biopsy specimen fixatives (sediment cytology) were used to study 65 bone specimens biopsied with suspicion of malignancy. The cytological diagnosis was then compared with histological diagnosis, taking the latter as gold standard. Smears were adequately cellular and showed good preservation of cellular morphology. Some of the smears showed microfragments of tissue. Cytology labeled 29 lesions as malignant, 26 lesions as benign, 3 as inflammatory, and 7 smears as inconclusive because of low cell yield. Sediment cytology was able to correctly diagnose 58 of 65 lesions. There was no false‐positive or false‐negative case. The sediment cytology could be considered as an easy and effective diagnostic tool that can provide early diagnosis for the lesion of bone. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc. 相似文献
83.
84.
Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes (surface area, changes in curvature and transportation) during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files (P = 0.226). During preparation there was failure of only one file (the protaper group). In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems. 相似文献
85.
Mohammad Murshid Alam Daniel T. Leung Marjahan Akhtar Mohammad Nazim Sarmin Akter Taher Uddin Farhana Khanam Deena Al Mahbuba Shaikh Meshbahuddin Ahmad Taufiqur Rahman Bhuiyan Stephen B. Calderwood Edward T. Ryan Firdausi Qadri 《Clinical and Vaccine Immunology : CVI》2013,20(10):1541-1548
Antibody avidity for antigens following disease or vaccination increases with affinity maturation and somatic hypermutation. In this study, we followed children and adults in Bangladesh for 1 year following oral cholera vaccination and measured the avidity of antibodies to the T cell-dependent antigen cholera toxin B subunit (CTB) and the T cell-independent antigen lipopolysaccharide (LPS) in comparison with responses in other immunological measurements. Children produced CTB-specific IgG and IgA antibodies of high avidity following vaccination, which persisted for several months; the magnitudes of responses were comparable to those seen in adult vaccinees. The avidity of LPS-specific IgG and IgA antibodies in vaccinees increased significantly shortly after the second dose of vaccine but waned rapidly to baseline levels thereafter. CTB-specific memory B cells were present for only a short time following vaccination, and we did not find significant memory B cell responses to LPS in any age group. For older children, there was a significant correlation between CTB-specific memory T cell responses after the second dose of vaccine and CTB-specific IgG antibody avidity indices over the subsequent year. These findings suggest that vaccination induces a longer-lasting increase in the avidity of antibodies to a T cell-dependent antigen than is measured by a memory B cell response to that antigen and that early memory T cell responses correlate well with the subsequent development of higher-avidity antibodies. 相似文献
86.
Rahma Mani Sabrina Belkacem Zohra Soua Sandra Chantot Guy Montantin Sylvie Tissier Bruno Copin Jihene Bouguila Nicolas Rive Le Gouard Lamia Boughamoura Salma Ben Ameur Mongia Hachicha Raoudha Boussoffara Khadija Boussetta Samia Hammouda Abir Bedoui Habib Besbes Seif Meddeb Karima Chraeit Monia Khlifa Estelle Escudier Serge Amselem Imed Mabrouk Marie Legendre 《Human mutation》2020,41(1):115-121
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disease of motile cilia. Even though PCD is widely studied, North‐African patients have been rarely explored. In this study, we aim at confirming the clinical diagnosis and explore the genetic spectrum of PCD in a cohort of Tunisian patients. Forty clinically diagnosed patients with PCD belonging to 34 families were recruited from Tunisian pediatric departments. In each proband, targeted capture PCD panel sequencing of the 40 PCD genes was performed. PCD panel sequencing identified bi‐allelic mutations in 82% of the families in eight PCD genes. Remarkably, 23.5% of patients carried the same c.2190del CCDC39 mutation. Single nucleotide polymorphism profiling in six unrelated patients carrying this mutation has revealed a founder effect in North‐African patients. This mutation is estimated to date back at least 1,400–1,750 years ago. The identification of this major allele allowed us to suggest a cost‐effective genetic diagnostic strategy in North‐African patients with PCD. 相似文献
87.
Paul McIntosh Andrew P. Southan Sobia Akhtar Christina Sidera Yuri Ushkaryov J. Oliver Dolly B. Robertson 《Pflügers Archiv : European journal of physiology》1997,435(1):43-54
We have examined the effects of co-expression of Kvβ1.1 and Kvβ2.1 subunits on the gating of rat brain Kv1.4 channels, expressed
in Xenopus oocytes. Expression of Kv1.4 subunits alone produced a rapidly inactivating ”A” type current, which activated at potentials
beyond –60 mV in a solution containing high levels of rubidium. Current activation curves obtained from tail current measurements
were fitted with a Boltzmann function, with V
1/2 = –47 mV and k = 10 mV. Neither the Kvβ1.1 nor Kvβ2.1 subunits altered the voltage dependence of activation. Both subunits accelerated the
activation time constant of Kv1.4, without affecting its voltage dependence. Surprisingly, the Kvβ2.1 subunit, which lacks
an N-terminal inactivation domain, was almost as effective as the Kvβ1.1 subunit in speeding up Kv1.4. Steady-state inactivation
of Kv1.4 was unchanged upon co-expression with either Kvβ1.1 or Kvβ2.1 subunits. Kv1.4 recovered from inactivation with two
time constants; apart from an ≈ 50% lengthening of the slow time constant with a high Kvβ2.1 injection ratio, neither time
constant was altered by either the Kvβ1.1 or Kvβ2.1 subunits, suggesting little interaction with recovery from C-type inactivation.
Clearly, β subunits have the potential to modify the gating of Kv1.4 channels in the brain more subtly than has been suggested
previously.
Received: 17 March 1997 / Accepted: 30 June 1997 相似文献
88.
Ana L Sanchez Carrie M Langdon Mahmood Akhtar Jun Lu Carl D Richards Premysl Bercik Derek M McKay 《Journal of interferon & cytokine research》2003,23(4):193-201
The use of biologics has promising potential in the treatment of inflammation. Studies with cultured cells and mouse models of disease have ascribed proinflammatory and anti-inflammatory functions to oncostatin M (OSM) and the related cytokine, interleukin-6 (IL-6). Here, we examined the effect of systemic administration of adenoviral (Ad) vectors encoding either murine OSM (AdMuOSM) or murine IL-6 (AdMuIL-6) in a mouse model of colitis. BALB/c mice were treated with a 5-day course of 4% dextran-sodium sulfate (DSS) water with or without administration of adenoviral vectors (i.p. or i.m. at 10(7) plaque-forming units [pfu]) given as a cotreatment or therapy. The deletion variant of the adenovirus served as a control for adenoviral infection. Colitis was assessed by (1) morphology (damage score, macrophage infiltration, apoptosis) and (2) function (myeloperoxidase activity and Ussing chamber analysis of epithelial ion transport). Infection with adenovirus alone did not affect colonic form or function. AdMuOSM (either i.p. or i.m.) significantly reduced the severity of the DSS-induced colitis. There was less damage, reduced macrophage infiltration, fewer apoptotic bodies, and a significant improvement in stimulated ion transport in colonic tissues from the treated mice. No benefit of AdMuIL-6 treatment was observed in this model system. Thus, systemic administration of AdMuOSM given as a cotreatment and to a lesser extent as a therapy was found to be of benefit in DSS-induced colitis, a murine model of inflammatory bowel disease (IBD). 相似文献
89.
Carles Vilario‐Güell Alexandra I. Soto Sarah J. Lincoln Samia Ben Yahmed Mounir Kefi Michael G. Heckman Mary M. Hulihan Hua Chai Nancy N. Diehl Rim Amouri Alex Rajput Deborah C. Mash Dennis W. Dickson Lefkos T. Middleton Rachel A. Gibson Faycal Hentati Matthew J. Farrer 《Human mutation》2009,30(3):406-410
Recessively inherited mutations in ATP13A2 result in Kufor‐Rakeb syndrome (KRS), whereas genetic variability and elevated ATP13A2 expression have been implicated in Parkinson disease (PD). Given this background, ATP13A2 was comprehensively assessed to support or refute its contribution to PD. Sequencing of ATP13A2 exons and intron‐exon boundaries was performed in 89 probands with familial parkinsonism from Tunisia. The segregation of mutations with parkinsonism was subsequently assessed within pedigrees. The frequency of genetic variants and evidence for association was also examined in 240 patients with nonfamilial PD and 372 healthy controls. ATP13A2 mRNA expression was also quantified in brain tissues from 38 patients with nonfamilial PD and 38 healthy subjects from the United States. Sequencing analysis revealed 37 new variants; seven missense, six silent, and 24 that were noncoding. However, no single ATP13A2 mutation segregated with familial parkinsonism in either a dominant or recessive manner. Four markers showed marginal association with nonfamilial PD, prior to correction for multiple testing. ATP13A2 mRNA expression was marginally decreased in PD brains compared with tissue from control subjects. In conclusion, neither ATP13A2 genetic variability nor quantitative gene expression in brain appears to contribute to familial parkinsonism or nonfamilial PD. Hum Mutat 0, 1–5, 2008. © 2008 Wiley‐Liss, Inc. 相似文献
90.
Sellami-Dhouib R Mrad K Sassi S Driss M Abbes I Mounir H Noureddine L Ammar B Ben Romdhane K 《Annales de pathologie》2007,27(3):247-250
Inflammatory pseudotumor (IPT) of the spleen is an uncommon entity with debated etiology, characterized by a mixture of inflammatory cells and a component of myofibroblastic spindle cells. This lesion needs to be distinguished from the follicular dendritic cell tumor and the inflammatory myofibroblastic tumor. We report two cases of splenic PTI in a 69-year old and a 62-year old women. The tumors measured respectively 80 and 30 mn in greatest dimension. An inflammatory pseudotumor was histopathologically diagnosed following a splenectomy. 相似文献