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11.
Andres A; Morales JM; Praga M; Campo C; Lahera V; Garcia-Robles R; Rodicio JL; Ruilope LM 《Nephrology, dialysis, transplantation》1997,12(7):1437-1440
BACKGROUND: Cyclosporin has been shown to facilitate renal vasoconstriction
and to have an antinatriuretic effect. The existence of an interference of
cyclosporin with the vasodilating properties of endothelium mediated by
nitric oxide production could mediate these effects. On the other hand, the
infusion of the nitric oxide precursor L-arginine has been shown to induce
renal vasodilatation and to facilitate natriuresis in normal volunteers. We
have investigated the renal effects of the administration of an infusion of
L-arginine in renal transplant patients chronically treated with
cyclosporin. To facilitate the analysis of the data the effects of the
administration of a similar dose of cyclosporin on renal function during
the infusion of a vehicle were also investigated during the administration
of a vehicle of L-arginine. DESIGN: Ten male renal transplant patients,
chronically treated with cyclosporin and with a stable renal function were
studied during 2 consecutive days after the administration of the usual
morning dose of cyclosporin. The first day they received an intravenous
infusion of vehicle and the second the infusion of graded doses of
L-arginine (50, 100, 150 mg/kg/h) during 3 consecutive h. RESULTS: The
first day, after cyclosporin administration a significant fall (P <
0.01) was observed in natriuresis and kaliuresis in the absence of changes
in renal plasma flow and glomerular filtration rate. After the
administration of L-arginine significant (P < 0.01) increases of renal
plasma flow, glomerular filtration rate, and natriuresis were seen. The
increase in blood levels of cyclosporin after its administration did not
differ between days 1 and 2. CONCLUSION: These results indicate that
L-arginine facilitates renal vasodilatation and natriuresis in renal
transplant patients. Furthermore, the observed increase in sodium excretion
could indicate that L-arginine counteracts the antinatriuretic effect of
cyclosporin.
相似文献
12.
Does altered biomechanics cause marrow edema? 总被引:21,自引:0,他引:21
13.
U. Kroitzsch G. Laufer E. Egkher G. Wollenek R. Horvath 《Archives of orthopaedic and trauma surgery》1989,108(1):44-48
Summary Excimer lasers have been demonstrated to provide a very precise and circumscribed ablation of synthetic polymers and biological tissues. We investigated in vitro the use of ultrashort pulsed ultraviolet excimer-laser energy for controlled removal of meniscus cartilage under the aspects of arthroscopic meniscectomy. A krypton-fluorine gas mixture was used to achieve laser emission of 248-nm wavelength. A total of 22 human menisci obtained either by operation or necropsy were irradiated over a range of energy fluence (2.15–3.07 J/cm2/pulse), repetition rates (5–20 Hz), and exposure time (15–60 s). Ablation rates of 4.00–5.76 m per pulse were obtained. Light-microscopic examinations demonstrated tissue ablation without any evidence of pathological changes associated with continuous-wave laser irradiation. Effects of laser energy were clearly limited to the target of the laser beam, and tissue removal proceeded without production of heat or smoke. Due to the lack of pathological alterations observed, excimer-laser irradiation of meniscus cartilage may prove to be advantageous for precisely cutting and removing menisci without injury to the surrounding normal tissue. Clinical application of excimer-laser irradiation includes the development of suitable fiberoptics and laser coupling, as well as modification of fiber tips.Funds were received from theFonds zur Förderung der wissenschaftlichen Forschung (Ministry of Science and Research, Austria) 相似文献
14.
15.
16.
Origin, Possible Function and Fate of “Follicular Cells” in the Anterior Lobe of the Human Pituitary: An Electron Microscopic Study 下载免费PDF全文
In human anterior pituitaries, follicular structures were found to develop by transformation of various types of glandular cells around foci of ruptured granulated cells undergoing destruction. In phase I, junctional complexes between granulated cells, as well as microvilli at the luminal surfaces of cell membranes, are formed. In phase II, degranulation and dedifferentiation of cytoplasm dominate the picture. Phase III follicular cells are practically devoid of secretory granules and other ultrastructural features characteristic of granulated cells. The participation of cell types in follicle formation does not appear to be limited. The follicular content in phase I-II is clearly recognizable as cellular debris from adenohypophysiocytes. These findings indicate that neither follicles nor junctional complexes are necessarily permanent structures of the anterior pituitary. It can be assumed that substances escaping from ruptured granulated cells may induce the formation of junctional complexes between adjacent cells. 相似文献
17.
R P Gaykema C Nyakas E Horvath L B Hersh C Majtenyi P G Luiten 《Neurobiology of aging》1992,13(3):441-448
Innervation density and morphological aberrations of cholinergic fibers were studied with choline acetyltransferase (ChAT) immunocytochemistry and acetylcholinesterase (AChE) histochemistry in 30-35 month-old aged rats and rats with long-term bilateral lesions of the magnocellular basal nucleus (MBN). In addition, AChE histochemistry was performed on human cortical sections derived from autopsy brains of normal aged and Alzheimer's disease (AD) patients. A limited but variable number of morphological alterations were observed in ChAT-immunoreactive fibers in the cortex and the hippocampus of the aged control rats. The aged MBN-lesioned rats displayed a severely reduced number of cholinergic fibers in the denervated areas of the neocortex, whereas the surviving fibers showed a strongly increased number of aberrations. Fiber anomalies were also observed in the cortex of the aged human subjects and Alzheimer patients, the latter showing a higher incidence of such aberrations. Only a part of these distended profiles were seen in close association with senile plaques as detected in the AChE-stained material. These findings suggest that experimental MBN lesions combined with aging share with AD the induction of large quantities of fiber malformations. Implications of possible mechanisms in both conditions are discussed. 相似文献
18.
Gropp E Shanabrough M Borok E Xu AW Janoschek R Buch T Plum L Balthasar N Hampel B Waisman A Barsh GS Horvath TL Brüning JC 《Nature neuroscience》2005,8(10):1289-1291
Multiple hormones controlling energy homeostasis regulate the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus. Nevertheless, inactivation of the genes encoding NPY and/or AgRP has no impact on food intake in mice. Here we demonstrate that induced selective ablation of AgRP-expressing neurons in adult mice results in acute reduction of feeding, demonstrating direct evidence for a critical role of these neurons in the regulation of energy homeostasis. 相似文献
19.
H. Oka T. Kameya H. Sasano M. Aiba K. Kovacs E. Horvath Y. Yokota N. Kawano K. Yada 《Virchows Archiv : an international journal of pathology》1996,427(6):613-617
A pituitary tumour composed of well-differentiated corticotrophs and adrenocortical cells is reported. Sections of the tumour revealed a mixture of small round cells with amphophilic or basophilic periodic acid-Schiff (PAS)-positive cytoplasm and large spherical and oval cells with abundant, granular, partly vacuolated PAS-negative cytoplasm. The small cells contained type 1 cytokeratin-positive microfilaments, numerous 250–500 nm endocrine-type secretory granules immunoreactive for adenocorticotropic hormone (ACTH) and -lipotropin. The large cells possessed ample cytoplasm filled with abundant vesicular smooth endoplasmic reticulum, numerous mitochondria possessing tubulovesicular cristae and frequent dense bodies. They lacked the features of pituitary endocrine cells or folliculostellate cells and were found to contain a panel of steroidogenic dehydrogenases and hydroxylases. The tumour was classified as a choristoma, in which two distinct cells types, corticotrophs and adrenocortical cells, were mixed. We suggest that, under continued ACTH stimulation, uncommitted stem cells may differentiate into adrenocortical cells. Alternatively, the presence of adrenocortical cells may be the result of heterotopia. 相似文献
20.
Analysis of endocrine active and clinically silent corticotropic adenomas by in situ hybridization. 下载免费PDF全文
R. V. Lloyd K. Fields L. Jin E. Horvath K. Kovacs 《The American journal of pathology》1990,137(2):479-488
The distribution of pro-opiomelanocortin (POMC) messenger RNA (mRNA) in 7 functional and 17 clinically silent corticotropic adenomas was analyzed by in situ hybridization (ISH) with 35S-labeled oligonucleotide probes using formalin-fixed paraffin-embedded tissue sections cut from blocks that were in storage between 1 to 14 years. All 7 functional adenomas and 4 subtype 1 tumors had detectable POMC mRNA, while 3 of 6 subtype 2 and 1 of 7 subtype 3 silent adenomas contained detectable POMC mRNA. In situ hybridization analysis with an 35S-labeled beta-actin probe showed a positive hybridization signal in 22 of 22 cases, indicating that the absence of detectable POMC mRNA in some adenomas was not due to loss of the mRNAs during processing of the tissues or because of the age of the embedded tissue blocks. Northern hybridization analysis with the oligonucleotide probes in 2 normal pituitaries and an adenoma causing Cushing's disease detected a 1.2-Kb mRNA in all three tissues, indicating that the oligonucleotide probes were very specific. These results indicate that subtype 1 silent adenomas and clinically active adenomas associated with Cushing's disease contain POMC mRNA that is readily detectable by ISH in routinely processed tissue specimens, while only a few of the subtypes 2 and 3 adenomas have POMC mRNA that can be detected in paraffin blocks with the oligonucleotide probes used in this study. 相似文献