全文获取类型
收费全文 | 7478篇 |
免费 | 363篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 158篇 |
儿科学 | 256篇 |
妇产科学 | 219篇 |
基础医学 | 1318篇 |
口腔科学 | 160篇 |
临床医学 | 615篇 |
内科学 | 1347篇 |
皮肤病学 | 233篇 |
神经病学 | 673篇 |
特种医学 | 435篇 |
外国民族医学 | 3篇 |
外科学 | 950篇 |
综合类 | 39篇 |
一般理论 | 2篇 |
预防医学 | 362篇 |
眼科学 | 251篇 |
药学 | 447篇 |
中国医学 | 74篇 |
肿瘤学 | 311篇 |
出版年
2022年 | 39篇 |
2021年 | 76篇 |
2020年 | 52篇 |
2019年 | 94篇 |
2018年 | 103篇 |
2017年 | 93篇 |
2016年 | 105篇 |
2015年 | 139篇 |
2014年 | 162篇 |
2013年 | 248篇 |
2012年 | 372篇 |
2011年 | 373篇 |
2010年 | 256篇 |
2009年 | 230篇 |
2008年 | 337篇 |
2007年 | 346篇 |
2006年 | 334篇 |
2005年 | 316篇 |
2004年 | 309篇 |
2003年 | 330篇 |
2002年 | 306篇 |
2001年 | 149篇 |
2000年 | 156篇 |
1999年 | 140篇 |
1998年 | 99篇 |
1997年 | 81篇 |
1996年 | 50篇 |
1995年 | 58篇 |
1994年 | 41篇 |
1993年 | 45篇 |
1992年 | 72篇 |
1991年 | 70篇 |
1990年 | 64篇 |
1989年 | 56篇 |
1988年 | 72篇 |
1987年 | 59篇 |
1986年 | 57篇 |
1985年 | 68篇 |
1984年 | 44篇 |
1983年 | 39篇 |
1979年 | 45篇 |
1978年 | 48篇 |
1977年 | 43篇 |
1975年 | 40篇 |
1971年 | 45篇 |
1933年 | 37篇 |
1930年 | 38篇 |
1929年 | 46篇 |
1928年 | 44篇 |
1922年 | 38篇 |
排序方式: 共有7853条查询结果,搜索用时 31 毫秒
71.
Repeated measurements of body composition and subcutaneous fat distribution were obtained in female gymnasts to test the hypothesis of a selective response from localized fat deposits to intense physical training. Repeated measurements were obtained on the members of three nationally ranked collegiate gymnastic teams: at the beginning and peak of the training season. The highest ranked team was measured a third time, three weeks after the end of the competitive season. Body composition was estimated using anthropometry and bioelectric impedance; subcutaneous fat thickness was measured using skinfold calipers and ultrasound images of adipose tissue thickness (ATT). The mean difference between baseline and peak measurements were statistically significant (P ? .05) for the triceps and suprailiac skinfolds, and for the adipose tissue thickness at the suprailiac and hypogastric sites. There were no significant changes in weight, percentage of body fat, circumferences, or subcutaneous fat thickness at the subscapular, calf or medial thigh sites. In the team with three sets of measurements, only the triceps skinfold and the suprailiac ATT showed a statistically significant effect of training. © 1993 Wiley-Liss, Inc. 相似文献
72.
T. Deufel I. Paetzke D. Pongratz G. Hübner O. H. Wieland 《Journal of molecular medicine (Berlin, Germany)》1984,62(14):651-658
Summary In the diagnosis of metabolic myopathies the use of biochemical methods, in addition to morphological examination of muscle biopsies, is often necessary in order to identify a specific metabolic defect. In order to narrow down the spectrum of biochemical methods, extensive clinical investigation and morphological examination, including histology, enzyme histochemistry and electromicroscopy if necessary have to be done beforehand. Patients are classified in the following groups: 1) progressive muscular weakness and/or muscle wasting with storage of a) glycogen, b) lipid or c) mitochondrial alterations; 2) recurrent rhabdomyolysis induced by fasting or exercise a) with glycogen storage or b) without any specific morphological alterations. The spectrum of metabolic defects comprises disorders of glycogen and glucose metabolism (deficiency of acid maltase, debranching and branching enzyme, phosphorylase, phosphofructokinase and other glycolytic enzymes), lipid metabolism (carnitine deficiency, carnitine palmitoyl transferase deficiency), mitochondria (respiratory chain disorders, pyruvate dehydrogenase deficiency) and others such as adenylate deaminase deficiency. In some of these e.g. infantile acid maltase deficiency and mitochondriopathies, it is clinically more important when organs other than muscle are affected; however, muscle biopsy is a useful substrate for diagnosis of these metabolic disorders.
Mit Unterstützung durch die DFG und die Friedrich Baur Stiftung, München 相似文献
73.
Chiral combined liquid-crystalline polymers (i. e. polymers with the mesogenic groups in the main chain as well as in the side groups) with dipole moments perpendicular to the mesogenic groups were synthesized and characterized. These dipole moments were introduced by lateral substituents, which were located at different parts of the mesogen or directly at the chiral centre. The polymers, thus prepared, show crystalline or glassy phases at room temperature and smectic A, chiral smectic C* or cholesteric phases at higher temperatures. Since the lateral substituents decrease the melting temperature more strongly than the clearing temperature, the liquid-crystalline phases are broadened compared to the unsubstituted polymers. Often glassy liquid-crystalline phases are obtained. The dipole moments perpendicular to the mesogenic groups or at the chiral centre may help to obtain a high spontaneous polarisation in the chiral smectic C* phase (ferroelectricity). 相似文献
74.
Implanted biomaterials are coated immediately with host plasma constituents, including extracellular matrix (ECM); this reaction may be undesirable in some cases. Poly(L-lysine)-grafted-poly(ethylene glycol) (PLL-g-PEG) has been shown to spontaneously adsorb from aqueous solution onto metal oxide surfaces, effectively reducing the degree of non-specific adsorption of blood and ECM proteins, and decreasing the adhesion of fibroblastic and osteoblastic cells to the coated surfaces. Cell adhesion through specific peptide-integrin receptors could be restored on surfaces coated with PLL-g-PEG functionalized with peptides of the RGD (Arg-Asp-Gly) type. To date, no study has examined the effect of surface modifications by PLL-g-PEG-based polymers on bacterial adhesion. The ability of Staphylococcus aureus to adhere to the ECM and plasma proteins deposited on biomaterials is a significant factor in the pathogenesis of medical-device-related infections. This study describes methods for visualizing and quantifying the adhesion of S. aureus to smooth and rough (chemically etched) titanium surfaces without and with monomolecular coatings of PLL-g-PEG, PLL-g-PEG/PEG-RGD and PLL-g-PEG/PEG-RDG. The different surfaces were exposed to S. aureus cultures for 1-24h and bacteria surface density was evaluated using scanning electron microscopy and fluorescence microscopy. Coating titanium surfaces with any of the three types of copolymers significantly decreased the adhesion of S. aureus to the surfaces by 89-93% for PLL-g-PEG, and 69% for PLL-g-PEG/PEG-RGD. Therefore, surfaces coated with PLL-g-PEG/PEG-RGD have the ability to attach cells such as fibroblasts and osteoblasts while showing reduced S. aureus adhesion, resulting in a selective biointeraction pattern that may be useful for applications in the area of osteosynthesis, orthopaedic and dental implantology. 相似文献
75.
Infiltrating mononuclear cells in human breast carcinoma: predominance of T4+ monocytic cells in the tumor stroma 总被引:1,自引:0,他引:1
Heinrich G. Gttlinger Peter Rieber Josef M. Gokel Klaus J. Lohe Gert Riethmüller 《International journal of cancer. Journal international du cancer》1985,35(2):199-205
Frozen sections of 52 breast carcinomas were examined for the presence and nature of a leukocytic infiltrate. The number of "common leukocyte (T200-) antigen"-bearing cells was remarkably high in the stromal compartment of the carcinomas, whereas the tumor foci themselves were usually infiltrated only sparsely. Approximately 80% of these T200+ stromal cells carried the myelomonocyte lineage-associated antigens M-M522 and 63D3 and exhibited "non-specific esterase" activity. More than 2/3 of the stromal monocytic cells expressed the T4 antigen as verified by monoclonal antibodies (MAbs) directed against different T4-associated epitopes. A T-cell analysis showed that T4+ cells clearly outweighed the total number of T cells as defined by anti-T3 and anti-TII antibodies. In addition, a correlation became apparent between the HLA-DR phenotype and the T lymphocyte content of tumor cell areas in the sense that densely infiltrated tumor areas were invariably HLA-DR+. 相似文献
76.
Fabian Heinrich Kira Meißner Felicia Langenwalder Klaus Püschel Dominik Nrz Armin Hoffmann Marc Lütgehetmann Martin Aepfelbacher Eric Bibiza-Freiwald Susanne Pfefferle Axel Heinemann 《Emerging infectious diseases》2021,27(1):329
Analyses of infection chains have demonstrated that severe acute respiratory syndrome coronavirus 2 is highly transmissive. However, data on postmortem stability and infectivity are lacking. Our finding of nasopharyngeal viral RNA stability in 79 corpses showed no time-dependent decrease. Maintained infectivity is supported by virus isolation up to 35 hours postmortem. 相似文献
77.
78.
Recently we reported that perfusion of hippocampal slices with epidermal growth factor (EGF) lead to enhancement of potentiated responses after tetanic stimulation. In the present study we report that basic fibroblast growth factor (FGF) can also lead to an enhancement of potentiated responses. FGF is a mitogen for several cell types and exhibits neurotrophic effects on neurons of the central nervous system (CNS). Rat hippocampal slices were perfused with FGF at a concentration of 10-9 M. During extra- and intracellular recordings in the CA1-region, the addition of FGF to the perfusing medium produced no change in evoked responses if single pulse or paired pulse stimulation was used. Furthermore FGF had no influence on the resting membrane potential and input resistance. However, after tetanic stimulation, FGF-treated slices showed an increase in the magnitude of potentiation compared to control slices. Taken together with the EGF data these results support the hypothesis that growth factors like FGF with neurotrophic potential on CNS-neurons can influence synaptic efficacy. Furthermore these results show that factors which are able to modulate developmental plasticity and regenerative plasticity can also modulate synaptic plasticity. 相似文献
79.
Endoscopic cordectomy. a proposal for a classification by the Working Committee, European Laryngological Society 总被引:6,自引:0,他引:6
M. Remacle Hans E. Eckel Antonio Antonelli Daniel Brasnu Dominique Chevalier Gerhard Friedrich Jan Olofsson Heinrich H. Rudert Walter Thumfart Marco de Vincentiis Thomas P. U. Wustrow 《European archives of oto-rhino-laryngology》2000,257(4):227-231
The European Laryngological Society is proposing a classification of different laryngeal endoscopic cordectomies in order
to ensure better definitions of postoperative results. We chose to keep the word “cordectomy” even for partial resections
because it is the term most often used in the surgical literature. The classification comprises eight types of cordectomies:
a subepithelial cordectomy (type I), which is resection of the epithelium; a subligamental cordectomy (type II), which is
a resection of the epithelium, Reinke’s space and vocal ligament; transmuscular cordectomy (type III), which proceeds through
the vocalis muscle; total cordectomy (type IV); extended cordectomy, which encompasses the contralateral vocal fold and the
anterior commissure (type Va); extended cordectomy, which includes the arytenoid (type Vb); extended cordectomy, which encompasses
the subglottis (type Vc); and extended cordectomy, which includes the ventricle (type Vd). Indications for performing those
cordectomies may vary from surgeon to surgeon. The operations are classified according to the surgical approach used and the
degree of resection in order to facilitate use of the classification in daily practice. Each surgical procedure ensures that
a specimen is available for histopathological examination.
Received: 29 December 1998 / Accepted: 2 July 1999 相似文献
80.
A. Wolkin E. Duncan M. Sanfilipo S. Wieland T. B. Cooper J. Rotrosen 《Journal of neural transmission (Vienna, Austria : 1996)》1994,95(1):49-61
Summary The purpose of this study was to evaluate the hypothesis that neuroleptic non-response in the face of adequate DA post-synaptic receptor blockade reflects failure of regulatory mechanisms to decrease DA pre-synaptic activity. Eight chronic schizophrenics, meeting rigorous criteria for neuroleptic non-response, were treated for four weeks with alpha-methylparatyrosine as an adjunct to their previously stable neuroleptic dose. Treatment with AMPT produced a prompt decrease in plasma HVA that was, on average, 72% lower at the end of the study. While there was also strong clinical evidence of reduction in central dopaminergic activity (both a significant reduction in dyskinetic movements and increase in extrapyramidal symptoms), there was virtually no change in severity of psychotic symptoms. Thus, in this group of non-responders, psychotic symptoms persisted despite both extensive dopamine post-synaptic receptor blockade and marked reduction of presynaptic activity. These symptoms may not be directly DA dependent. 相似文献