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61.
Iman Al‐Saleh Andrew Taylor Richard Hinton 《International journal of environmental health research》1992,2(4):184-191
Erythrocyte protoporphyrin and blood lead concentrations were measured in samples from 583 Saudi children attending the outpatient clinics. Erythrocyte protoporphyrin concentrations showed poor correlation with blood lead concentrations of 25 ug dl?1 and below. Measurement of erythrocyte protoporphyrin as a primary test for lead exposure is not recommended. 相似文献
62.
63.
Acute colonic pseudo-obstruction (ACPO), also known as Ogilvie’s syndrome, is a rare condition associated with massive dilatation
of the colon in the absence of any mechanical obstruction. Between 4 and 35% of all reported cases of ACPO have occurred in
association with pregnancy or puerperium, with most of these occurring after caesarean sections. We present a case report
of the successful management of a patient with ACPO. 相似文献
64.
Guillain-barré syndrome: A series observed at riyadh armed forces hospital january 1984–January 1994
A consecutive series of 47 hospitalized cases of Guillain-Barré syndrome seen over a 10-year period was analysed with respect
to: (1) age and sex; (2) antecedent events and seasonal distribution; (3) patterns of clinical presentation; (4) CSF and neurophysiological
findings; (5) results of treatment with plasma exchange; and (6) outcome. Twenty-two were children, 20 middle-aged and 5 aged;
37 were male and 10 were female. The most frequent antecedent event was upper respiratory tract infections; a seasonal peak
incidence was found in winter. Clinical, CSF and neurophysiological findings concurred with those in the Western literature;
79% of the cases were severe. Plasma exchange performed within the first 2 weeks of onset benefitted in the short-term outcome,
i.e. improvement by 1 grade at 4 weeks, but the long-term benefit, i.e. the ability to regain independent locomotion, was
questionable. Plasma exchange helped in curtailing the time to walking unaided but had no benefit on the duration of artificial
ventilation. Factors associated with an adverse outcome were: age over 15 years, severity of motor electrodiagnostic findings
(especially a decreased distal CMAP amplitude and EMG signs of acute denervation), requirement for ventilation and slow progression
(>3 weeks) to maximum deficit. After a mean follow-up of 11 months, 55% of the patients regained independent locomotion, which
is a comparatively low proportion. 相似文献
65.
66.
Mechanotransduction of bone cells<Emphasis Type="Italic">in vitro</Emphasis>: Mechanobiology of bone tissue 总被引:11,自引:0,他引:11
Mullender M El Haj AJ Yang Y van Duin MA Burger EH Klein-Nulend J 《Medical & biological engineering & computing》2004,42(1):14-21
Mechanical force plays an important role in the regulation of bone remodelling in intact bone and bone repair. In vitro, bone
cells demonstrate a high responsiveness to mechanical stimuli. Much debate exists regarding the critical components in the
load profile and whether different components, such as fluid shear, tension or compression, can influence cells in differing
ways. During dynamic loading of intact bone, fluid is pressed through the osteocyte canaliculi, and it has been demonstrated
that fluid shear stress stimulates osteocytes to produce signalling molecules. It is less clear how mechanical loads act on
mature osteoblasts present on the surface of cancellous or trabecular bone. Although tissue strain and fluid shear stress
both cause cell deformation, these stimuli could excite different signalling pathways. This is confirmed by our experimental
findings, in human bone cells, that strain applied through the substrate and fluid flow stimulate the release of signalling
molecules to varying extents. Nitric oxide and prostaglandin E2 values increased by between two- and nine-fold after treatment with pulsating fluid flow (0.6±0.3 Pa). Cyclic strain (1000
μstrain) stimulated the release of nitric oxide two-fold, but had no effect on prostaglandin E2. Furthermore, substrate strains enhanced the bone matrix protein collagen I two-fold, whereas fluid shear caused a 50% reduction
in collagen I. The relevance of these variations is discussed in relation to bone growth and remodelling. In applications
such as tissue engineering, both stimuli offer possibilities for enhancing bone cell growth in vitro. 相似文献
67.
68.
J E Alés-Martinez D W Scott R P Phipps J E Casnellie G Kroemer C Martinez L Pezzi 《European journal of immunology》1992,22(3):845-850
Although displaying similar amounts of surface IgM and IgD, ECH 408-1 cells only succumb to apoptosis after cross-linking of IgM (not IgD), suggesting that different signaling pathways couple to both receptors. Immunoprecipitation studies revealed the presence of several proteins selectively associated with IgM and IgD, thus ruling out that the lack of inhibitory signaling mediated by IgD might be due to membrane expression in the absence of associated proteins belonging to the B cell receptor complex. 32P metabolic labeling and immunoprecipitation studies demonstrated that IgM and IgD are associated with phosphoproteins of 32-33 kDa in an isotype-specific fashion. Kinetic analyses of tyrosine kinase activity showed that cross-linking of surface IgM or IgD resulted in the rapid (1-3 min) phosphorylation of several protein substrates on tyrosine residues, followed by a dephosphorylation step. Isotype-specific changes of the phosphorylation status specifically affected molecules in the 32-33 kDa range, i.e. IgM (not IgD) cross-linking affected a approximately 32-kDa protein, whereas IgD (not IgM) cross-linking induced phosphorylation of a protein exhibiting a slightly lower mobility (33 kDa). These results suggest that isotype-specific immunoglobulin-associated molecules could be involved in the second messenger cascade leading to different biological effects upon IgM and IgD cross-linking. 相似文献
69.
Szalay F Zsarnovszky A Fekete S Hullár I Jancsik V Hajós F 《Anatomy and embryology》2001,203(1):53-59
Piglets born with spread-leg syndrome, a congenital weakness of the hindlimb adductors, were investigated to determine the site of lesion leading to limb impairment. Histological and immunohistochemical studies of the motor neuron unit showed no alterations but quantitative analysis revealed a reduction of axonal diameter and myelin sheath-thickness of the fibres innervating the adductors of the affected limbs. In the lumbar spinal cord a lack of myelination was observed in the tracts descending to the lower motor neurons. Recovery from the syndrome was accompanied by a catching-up of myelination with that of the controls. The spread-leg syndrome is due to a nutritional deficiency in the sow; thus it is assumed that the deficient maternal substances, mainly choline and methionine, are essential for the normal myelin production by spinal white matter oligodendrocytes of the fetus. 相似文献
70.
Mohammad M. Al‐Qattan Fowzan S. Alkuraya 《American journal of medical genetics. Part A》2019,179(2):266-279
Cenani–Lenz (C–L) syndrome is characterized by oligosyndactyly, metacarpal synostosis, phalangeal disorganization, and other variable facial and systemic features. Most cases are caused by homozygous and compound heterozygous missense and splice mutations of the LRP4 gene. Currently, the syndrome carries one OMIM number (212780). However, C–L syndrome‐like phenotypes as well as other syndactyly disorders with or without metacarpal synostosis/phalangeal disorganization are also known to be associated with specific LRP4 mutations, adenomatous polyposis coli (APC) truncating mutations, genomic rearrangements of the GREM1‐FMN1 locus, as well as FMN1 mutations. Surprisingly, patients with C–L syndrome‐like phenotype caused by APC truncating mutations have no polyposis despite the increased levels of β catenin. The LRP4 and APC proteins act on the WNT (wingless‐type integration site family) canonical pathway, whereas the GREM‐1 and FMN1 proteins act on the bone morphogenetic protein (BMP) pathway. In this review, we discuss the different mutations associated with C–L syndrome, classify its clinical features, review familial adenomatous polyposis caused by truncating APC mutations and compare these mutations to the splicing APC mutation associated with syndactyly, and finally, explore the pathophysiology through a review of the cross talks between the WNT canonical and the BMP antagonistic pathways. 相似文献