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排序方式: 共有2234条查询结果,搜索用时 15 毫秒
141.
Lee NK Son KH Chang HW Kang SS Park H Heo MY Kim HP 《Archives of pharmacal research》2004,27(11):1132-1135
In order to find new tyrosinase inhibitors and the effects of prenyl residue on flavonoid molecules, eight prenylated and three synthetic vinylated flavonoids were examined on their inhibitory effect against tyrosinase activity. From the results, kuwanon C, papyriflavonol A, sanggenon D and sophoflavescenol were found to possess the considerable inhibitory activity. Especially, sanggenon D is revealed as a potent inhibitor (IC50 = 7.3 microM), compared to the reference compound, kojic acid (IC50 = 24.8 microM). However, the prenylation with isoprenyl group or the vinylation to flavonoid molecules did not enhance tyrosinase inhibitory activity. 相似文献
142.
1. Chronic alcohol treatment has been reported to be associated with liver and kidney damage. The insulin-like growth factor (IGF) is the major growth factor related to alcohol consumption. However, the effect of alcohol on the IGF system in the liver and kidney has not been fully elucidated. Thus, the present study was conducted to investigate this issue. 2. Alcohol reduced the level of IGF-I in a dose-dependent manner in the serum, liver and kidney. Alcohol also decreased the level of IGF-II in the liver. In contrast, alcohol increased the level of IGF-II in the serum and kidney. These observations were correlated with IGF-I and IGF-II mRNA expression in the liver and kidney. 3. To examine the effect of alcohol on IGF receptors in the liver and kidney, IGF-I receptor mRNA was measured. Alcohol decreased IGF-I receptor mRNA in the liver and kidney. 4. In experiments performed to examine the regulation of IGF-binding proteins (IGFBP), alcohol increased serum levels of IGFBP-1. However, alcohol had no effect on serum levels of IGFBP-2, -3 and -4. These effects were also observed in the liver and kidney. 5. In conclusion, alcohol alters the IGF system in rat liver and kidney in a tissue-specific manner, which may contribute to the metabolic dysfunction following chronic alcohol consumption. 相似文献
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AlamarBlue is used to induce color and fluorescence in the microenvironment of activated cells. The alamarBlue assay was studied to determine if it could be used as a method of evaluating the number of retinal pigment epithelial (RPE) cells. A series of two-fold dilutions of RPE cells were placed into 96-well culture plates. The alamarBlue was added to the culture media after attaching the cells. The absorbance and fluorescence were measured consecutively at various intervals over a period of 24 hr. Cell viability were evaluated by means of the trypan blue exclusion method and flow cytometry using a combination of propidium iodide and annexin V was done to prove the safety of alamarBlue assay to the cells. Both the absorbance and the fluorescence had a linear relationship with the number of RPE cells. Exposing the RPE cells to alamarBlue was not detrimental to the cells. In conclusion, the alamarBlue assay constitutes a one-step, extremely simple, reproducible, economical and non-toxic procedure for evaluating the number of viable RPE cells. 相似文献
146.
To investigate the effect of nitric oxide (NO) on the proliferation of trabecular meshwork (TM) cells, primarily cultured porcine TM cells were exposed to NO donor (SNAP, S-nitroso-N-acetyl-D,L-penicillamine) with and without its inhibitor (L-NAME, Nomega-Nitro-L-arginine methyl ester). The proliferation of TM cells was quantified by a rapid colorimetric assay. Acridine orange/Hoechest 33342 staining and flow cytometry with annexin-PI were done. As a result, NO inhibited the proliferation of TM cells significantly in a dose-dependent manner and this inhibitory effect was abolished by L-NAME. Fluorescent microscopy and flow cytometric analysis revealed that NO induced apoptotic cell death. The current results suggest that NO inhibit the proliferation of TM cells and apoptosis may be involved in some degree. 相似文献
147.
Bae YS Lee TG Park JC Hur JH Kim Y Heo K Kwak JY Suh PG Ryu SH 《Molecular pharmacology》2003,63(5):1043-1050
Phosphoinositide-specific phospholipase C (PLC) plays a pivotal role in the signal transduction of various cellular responses. However, although it is undeniably important that modulators of PLC activity be identified, no direct PLC activity modulator has been identified until now. In this study, by screening more than 10,000 different compounds in human neutrophils, we identified a compound that strongly enhances superoxide-generating activity, which is well known to be PLC-dependent. The active compound 2,4,6-trimethyl-N-(meta-3-trifluoromethyl-phenyl)-benzenesulfonamide (m-3M3FBS) stimulated a transient intracellular calcium concentration ([Ca(2+)](i)) increase in neutrophils. Moreover, m-3M3FBS stimulated the formation of inositol phosphates in U937 cells, indicating that it stimulates PLC activity. The compound showed no cell-type specificity in terms of [Ca(2+)](i) increase in the various cell lines including leukocytes, fibroblasts, and neuronal cells. We also ruled out the possible involvement of heterotrimeric G proteins in m-3M3FBS-stimulated signaling by confirming the following: 1) pertussis toxin does not inhibit m-3M3FBS-induced [Ca(2+)](i) increase; 2) m-3M3FBS does not stimulate cyclic AMP generation; and 3) the inhibition of G(q) by the regulator of G protein-signaling 2 does not affect the m-3M3FBS-induced [Ca(2+)](i) increase. We also observed that m-3M3FBS stimulated PLC activity in vitro. The purified isoforms of PLC that were tested (i.e., beta2, beta3, gamma1, gamma2, and delta1) were activated by m-3M3FBS and showed no isoform specificity. Taken together, these results demonstrate that m-3M3FBS modulates neutrophil functions by directly activating PLC. Because m-3M3FBS is the first compound known to directly activate PLC, it should prove useful in the study of the basic molecular mechanisms of PLC activation and PLC-mediated cell signaling. 相似文献
148.
Lee KW Kim DY Yun T Kim DW Kim TY Yoon SS Heo DS Bang YJ Park S Kim BK Kim NK 《Cancer》2003,98(12):2651-2656
BACKGROUND: Although many studies of elderly patients with non-Hodgkin lymphoma have focused on the dose intensity of chemotherapy, few studies have restricted the histologic inclusion criteria such that only patients with diffuse large B-cell lymphoma (DLCL) are considered. In the current study, treatment outcomes for elderly patients (age > or = 60 years) were analyzed, with emphasis on the dose intensity of doxorubicin. METHODS: Between 1994 and 2000, 195 patients with DLCL were treated initially with doxorubicin-based chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone; or cyclophosphamide, vincristine, bleomycin, doxorubicin, procarbazine, and prednisone). Of these patients, 70 were aged 60 years or older. RESULTS: Elderly patients had poorer treatment outcomes than did young patients (5-year survival, 30% vs. 57%; P < 0.001); however, elderly patients who received doxorubicin at dose intensities > or = 10 mg/m2 per week (n = 25) had outcomes (5-year survival, 52%) that were comparable to those of young patients. Among prognostic factors, only International Prognostic Index score (P = 0.022) and dose intensity of doxorubicin (P = 0.039) were found to have significant effects on the overall survival of elderly patients. When the reasons for doxorubicin dose reduction in 45 elderly patients who ultimately received doxorubicin at dose intensities < 10 mg/m2 per week were analyzed, it was found that 20 patients received reduced doses from the start of treatment because of their old age alone; these dose reductions in the 20 cases resulted in poorer treatment outcomes. CONCLUSIONS: Elderly patients with DLCL who received doxorubicin at dose intensities > or = 10 mg/m2 per week had treatment outcomes that were comparable to those of young patients; however, physician bias associated with patient age was found to be related to unnecessary dose reductions. Efforts to maintain doxorubicin dose intensities > or = 10 mg/m2 per week and more objective standards for the selection of elderly patients capable of tolerating doxorubicin-based regimens are required. 相似文献
149.
Excitatory effects of 5-hydroxytryptamine on the medial vestibular nuclear neuron via the 5-HT2 receptor 总被引:3,自引:0,他引:3
This study was designed to investigate the mechanisms of action of the 5-HT2 receptor on the spontaneous electrical activity and potassium currents of the rat medial vestibular nuclear neurons using whole-cell patch clamp recordings. The spike width of spontaneous action potential was not affected by 5-alpha-methylhydroxytryptamine. The spike frequency and resting membrane potential was increased by 5-alpha-methylhydroxytryptamine. The amplitude of afterhyperpolarization was decreased by 5-alpha-methylhydroxy-tryptamine. The peak current of the potassium currents of the neuron treated with 5-alpha-methylhydroxytryptamine was decreased. After blockade of calcium-dependent potassium currents, 5-alpha-methylhydroxytryptamine did not inhibit potassium currents. These results suggest 5-alpha-methylhydroxytryptamine increases spontaneous firing of the medial vestibular nuclear neurons by inhibiting calcium dependent potassium currents. 相似文献
150.
Effect of diesel exhaust particles and their components on the allergen-specific IgE and IgG1 response in mice 总被引:6,自引:0,他引:6
Increased antigen-specific IgE expression is a hallmark of the allergic response in mice. IgG1 may also be involved. Co-injection of mice with diesel exhaust particles (DEP) and ovalbumin three times over a 2 week period lead to a rapid and marked elevation of ovalbumin-specific IgE, IgG1 and also IgG2a, compared with ovalbumin alone. When DEP were injected 1 day before or after ovalbumin on each occasion, their adjuvant effect was considerably muted, suggesting that the adjuvant effect of DEP is short-lived, or that a physical interaction between ovalbumin and DEP is required. DEP were extracted with methylene chloride. Both the resulting core carbon particles and the organic extract enhanced ovalbumin specific IgE and IgG1 levels. Thus the adjuvant effect of DEP in this model is due both to the physical and the chemical attributes of the particles. The tricyclic hydrocarbons phenanthene (the most prevalent polycyclic aromatic hydrocarbon in DEP) and anthracene were both capable of enhancing antigen-specific IgE and IgG1 production. The phenolic antioxidant, butylated hydroxyanisole, which can affect gene expression via the antioxidant responsive element (ARE), had a lesser effect. Two agonists for the aryl hydrocarbon receptor, 3-methychloranthrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin, either were without effect or suppressed the response, suggesting that DEP adjuvancy may not be mediated by this receptor. 相似文献