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71.
Olof Lakmaker John W. Pickering Martin J. C. van Gemert 《Lasers in surgery and medicine》1993,13(2):219-226
To find the maximal depth of an ectatic vessel in the dermis that contributes to the abnormal color of a port wine stain (PWS), “normal” and “laser treated PWS skin” are modeled, respectively, as a two-layer plane parallel geometry consisting of an epidermis and a dermis, and as a three-layer geometry consisting of an epidermis, a dermis without additional blood (the “treated” part of the stain, assumed identical to the “normal” dermis), and a layer of dermis containing 5% or 10% of blood per volume (the untreated part of the PWS). Spectral remittances were calculated for various wavelengths using the diffusion approximation to the transport equation for light propagation. These remittances were transformed into the CIE 1976 (L*a*b*)-color system. Color differences between “normal” and PWS skin as a function of the dermal depth of “injured” ectatic blood vessels were calculated. The maximal depth where ectatic blood vessels just contribute to the abnormal PWS color is predicted as 0.9 mm for a “normally” pigmented epidermis (60 μm thick) and a 5% or 10% blood per volume content. For a darker pigmented epidermis (60 μm thickness) and again at both 5% and 10% blood per volume content, this depth was found to be 0.8 mm. © 1993 Wiley-Liss, Inc. 相似文献
72.
BACKGROUND AND OBJECTIVES: Two wavelengths, 585 and 595 nm, are currently common options for treating vascular malformations such as port-wine stains (PWS). Controversy exists as to which wavelength induces greater photothermal damage to the blood vessels and subsequent resolution of the malformations. STUDY DESIGN/MATERIALS AND METHODS: We irradiated normal, human skin in vivo at 585 and 595 nm wavelengths using fluences of 10-30 J/cm(2) with a 1.5 millisecond laser pulse. The level of purpura, total vascular damage, maximum coagulation depth (MCD), and perivascular damage were quantified by gross observation and histological analysis. RESULTS: Results demonstrated that 585 nm light caused greater purpura, vascular damage, maximum coagulation depth, and perivascular damage than 595 nm. Purpura showed a positive correlation with total vascular damage to a certain extent beyond which the total vascular damage did not change. For equivalent purpura, 585 and 595 nm produced no statistically significant difference in vascular damage. The difference in the laser-induced vascular damage between 585 and 595 nm, although statistically significant, was no more than 50%. CONCLUSIONS: The bathochromic (red) shift and formation of met-hemoglobin, which reduces the 585 nm light absorption and increases that of 595 nm compared to native oxy-hemoglobin, play a considerable role in creating more parity in vascular damage between the two wavelengths than would be expected based on their respective "native" absorption coefficients alone. 相似文献
73.
BACKGROUND AND OBJECTIVES: Laser irradiation is the current modality for treatment of cutaneous hypervascular malformations such as port wine stains and telangiectasia. Although cryogen spray cooling (CSC) is used to protect the epidermis from non-specific laser-induced thermal damage in moderately-pigmented skin types, individuals with high melanin content are still at risk for epidermal damage using the current laser irradiation and CSC parameters. The objective of this study was to investigate the influence of the spray Weber number (1,100 or 5,100) on epidermal protection and examine vascular coagulation in response to pulsed dye laser irradiation. STUDY DESIGN/MATERIALS AND METHODS: Normal, in vivo human skin from eight subjects of Fitzpatrick skin types I-V were precooled with either low or high Weber number cryogen sprays and subsequently irradiated with a pulsed dye laser at 595 nm. Analysis of gross purpura, morphological vascular damage, and apoptosis of the vascular walls were performed. RESULTS: Results demonstrated a high Weber number spray of 5,100 decreased the level of epidermal damage in darker and moderate pigmented individuals compared to a Weber number spray of 1,100. This study also established a positive correlation between gross purpura and the level of vessel wall apoptosis. CONCLUSIONS: This study has demonstrated that CSC with a high Weber number spray can decrease nonspecific thermal damage to the epidermis in response to laser irradiation in vivo. We have also established a positive correlation between gross purpura and the level of vessel wall apoptosis. Lasers Surg. Med. (c) 2005 Wiley-Liss, Inc. 相似文献
74.
Roland Berger Alain Bernheim François Sigaux Marie-Thérèse Daniel Françoise Valensi Georges Flandrin 《Leukemia research》1982,6(1):17-26
Cytogenetic studies have been performed on 34 acute monocytic leukemia (M5) patients, 24 of the a type and 10 of the b type. No chromosomal abnormalities were found in 12 cases, in spite of the fact that the mitoses concerned monocytes. Different chromosomal aberrations were present in the other cases. In 12 of them, an abnormality of the chromosome 11 long arm was observed (mainly in the poorly differentiated type of M5), on bands q22–q24 in nine cases and on band q14 in three cases. The chromosome 11 long arm thus appears preferentially rearranged in M5 although this is not apparent in every case. Concomitant study of the mitoses with cytological and cytogenetic techniques suggests that erythroblasts may not be involved in the M5 leukemic process. 相似文献
75.
Summary Motor nerve terminals in normal slow soleus and fast peroneus brevis muscles and reinnervated soleus muscles of rats were stained with methylene blue. Reinnervation was induced by cutting the original tibial nerve innervation, and was established either by the tibial nerve within the original innervation band or by the previously transposed foreign superficial peroneal nerve outside the innervation band. Terminals were classified as morphological types A, B, or C according to previously defined criteria, and their sizes were measured.In the normal muscles, type B terminals predominate in the soleus muscle, whereas type A ones predominate in the peroneus brevis muscle. In soleus muscles the size of the terminals increases with increasing animal size and age.In the reinnervated muscles the three types of terminals can be recognized.In the self-reinnervated soleus muscles the new terminals after 16 and 54 weeks conform with those occurring normally in soleus muscles.The first identifiable foreign terminals ten days after denervation resemble those in normal soleus muscles (type B). With increasing postdenervation time, however, terminals resembling type A ones increase in number at the expense of type B ones. Thus, 3 and 14 weeks after induced reinnervation, the frequency distribution of types of foreign terminals is changed and resembles that in normal peroneus brevis muscle. The development continues, however, and after a year most foreign terminals resemble type A ones, rendering the frequency distribution consistently different from that in normal soleus as well as peroneus brevis muscles. The size of the terminals steadily increases during this period, an increase beyond the normal increase with age.The results indicate that morphological features of the new motor nerve terminals formed in the experimental models used mainly depend on the type of motor axons reinnervating a muscle, modified however by the type of muscle fibers being reinnervated. 相似文献
76.
Is bacterial vaginosis a stronger risk factor for preterm birth when it is diagnosed earlier in gestation? 总被引:5,自引:0,他引:5
Klebanoff MA Hillier SL Nugent RP MacPherson CA Hauth JC Carey JC Harper M Wapner RJ Trout W Moawad A Leveno KJ Miodovnik M Sibai BM Vandorsten JP Dombrowski MP O'Sullivan MJ Varner M Langer O;National Institute of Child Health Human Development Maternal-Fetal Medicine Units Network 《American journal of obstetrics and gynecology》2005,192(2):470-477
OBJECTIVE: It is stated commonly that the earlier in pregnancy bacterial vaginosis is diagnosed, the greater is the increase in risk of preterm birth compared with women without bacterial vaginosis. However, this contention is based on small numbers of women. STUDY DESIGN: In this analysis of 12,937 women who were screened for bacterial vaginosis as part of a previously conducted clinical trial, the odds ratio of preterm birth (<7 weeks of gestation) for asymptomatic bacterial vaginosis-positive versus bacterial vaginosis-negative women was evaluated among women who were screened from 8 to 22 weeks of gestation. RESULTS: The odds ratio of preterm birth among bacterial vaginosis-positive versus bacterial vaginosis-negative women ranged from 1.1 to 1.6 and did not vary significantly according to the gestational age at which bacterial vaginosis was screened. The odds ratio for preterm birth did not vary significantly by gestational age at diagnosis when bacterial vaginosis was subdivided into Gram stain score 7 to 8 or 9 to 10. CONCLUSION: Although bacterial vaginosis was associated with an increased risk of preterm birth, the gestational age at which bacterial vaginosis was screened for and diagnosed did not influence the increase. 相似文献
77.
PURPOSE: The role of protein synthesis in mossy fiber sprouting is unclear. Conflicting reports exist on whether a single dose of the protein synthesis-blocker cycloheximide administered around the time of an epileptogenic injury can block the eventual development of mossy fiber sprouting. METHODS: In rats, osmotic minipumps and cannulae were implanted to deliver 8 mg/ml cycloheximide to one dentate gyrus and vehicle to the other. This method has been used to block protein synthesis in the infused region for up to 5 days with minimal neurotoxic effects (Taha and Stryker, Neuron 2002;34:425-36). After 2 days of infusion, rats were treated with pilocarpine to induce status epilepticus. Pumps were removed 3 days later. Thirty days after pilocarpine treatment, rats were perfused, and hippocampal sections were processed for Timm staining. RESULTS: Timm staining revealed aberrant mossy fiber sprouting in the inner molecular layer regardless of whether hippocampi were treated with cycloheximide or vehicle. Cycloheximide-treated hippocampi displayed more aberrant Timm staining and more tissue damage around the infusion site than did vehicle-treated hippocampi. CONCLUSIONS: Prolonged infusion of cycloheximide, spanning the period of pilocarpine treatment, did not block mossy fiber sprouting. This finding suggests that protein-dependent mechanisms around the time of an epileptogenic injury are not necessary for the eventual development of synaptic reorganization. 相似文献
78.
79.
We undertook this study to determine the detailed neuroanatomy of the terminal branches of the recurrent laryngeal nerve (RLN) in the rabbit to facilitate future neurophysiological recordings from identified branches of this nerve. The whole larynx was isolated post mortem in 17 adult New Zealand White rabbits and prepared using a modified Sihler's technique, which stains axons and renders other tissues transparent so that nerve branches can be seen in whole mount preparations. Of the 34 hemi-laryngeal preparations processed, 28 stained well and these were dissected and used to characterize the neuroanatomy of the RLN. In most cases (23/28) the posterior cricoarytenoid muscle (PCA) was supplied by a single branch arising from the RLN, though in five PCA specimens there were two or three separate branches to the PCA. The interarytenoid muscle (IA) was supplied by two parallel filaments arising from the main trunk of the RLN rostral to the branch(es) to the PCA. The lateral cricoarytenoid muscle (LCA) commonly received innervation from two fine twigs branching from the RLN main trunk and travelling laterally towards the LCA. The remaining fibres of the RLN innervated the thyroarytenoid muscle (TA) and comprised two distinct branches, one supplying the pars vocalis and the other branching extensively to supply the remainder of the TA. No communicating anastomosis between the RLN and superior laryngeal nerve within the larynx was found. Our results suggest it is feasible to make electrophysiological recordings from identified terminal branches of the RLN supplying laryngeal adductor muscles separate from the branch or branches to the PCA. However, the very small size of the motor nerves to the IA and LCA suggests that it would be very difficult to record selectively from the nerve supply to individual laryngeal adductor muscles. 相似文献
80.
BACKGROUND AND OBJECTIVES: Improved laser treatment of cutaneous hypervascular lesions is expected by utilizing higher incident dosages, longer pulse durations and longer wavelengths than those currently used in clinical settings. However, simply increasing the incident dosage will also increase the risk of nonspecific thermal injury to the epidermis due to light absorption by melanin. In this study, we investigated the thermal response of human skin epidermis to 595-nm wavelength laser irradiation at high incident dosages (up to 20 J/cm(2)) and long pulse durations (up to 40 milliseconds) in conjunction with cryogen spray cooling (CSC) using ex-vivo human skin samples. STUDY DESIGN/MATERIALS AND METHODS: The Candela V-beam trade mark laser (595-nm wavelength) was used in the experiments. Ex-vivo human skin samples (Fitzpatrick types I-VI) were irradiated at the incident dosages D(0) = 4, 6, 10, 15, and 20 J/cm(2), laser pulse durations tau(laser) = 1.5, 10, and 40 milliseconds, without and with CSC (refrigerant-134A, spurt duration tau(CSC) = 100 milliseconds). Thermal injury to the epidermis was evaluated by histological observations. RESULTS: Under the same incident dosage, longer pulse durations led to reduced thermal injury to the epidermis. Without CSC, no demonstrable thermal injury to the epidermis was observed in skin types I-II irradiated at the incident dosage as high as 15 J/cm(2), and in skin types III-IV at 10 J/cm(2). When CSC was applied, no evidence of thermal injury to the epidermis was present in skin types I-II even when irradiated at the maximum available incident dosage of the laser system (20 J/cm(2)). In skin types III-IV, no demonstrable thermal injury to the epidermis was observed when using incident dosage as high as 15 J/cm(2) in conjunction with CSC. In skin type VI, thermal injury to the epidermis could not be avoided even at the setting D(0) = 4 J/cm(2), tau(laser) = 40 milliseconds in conjunction with CSC. CONCLUSIONS: For a given incident dosage, longer pulse durations help reduce thermal injury to the epidermis. When a 100-millisecond cryogen spurt is applied, thermal injury to the epidermis can be prevented in ex-vivo skin types I-IV when irradiated at higher incident dosages (15-20 J/cm(2)) than those currently used in clinical settings. Further studies on optimizing the CSC parameters in conjunction with the laser irradiation parameters are needed to protect skin types V-VI from thermal injury to the epidermis. 相似文献