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71.
72.
Consuelo Garcia Emma S Calderón-Aranda Gerardo A V Anguiano Baltazar Becerril Lourival D Possani 《Toxicon》2003,41(4):417-427
Three different immunogens from the venom of the Mexican scorpion Centruroides noxius Hoffmann were used to study protective antibody response in mice and rabbits, challenged with toxin Cn2, one of the most abundant toxic peptide of this venom. The immunogens were: Cn5, a crustacean specific toxin; a recombinant protein containing the peptide Cn5 linked to the maltose transporter and a sub-fraction (F.II.5) containing 25 distinct peptides, among which is Cn5. Mice immunized with these three preparations, when directly challenged with Cn2 presented no apparent protection, whereas anti-sera produced in rabbits with these three immunogens were capable of partially neutralizing the effect of Cn2, when injected into naive mice. Cn5 rabbit anti-serum showed a better protective effect on mice, than the rabbit sera obtained against the two other antigens. The subcutaneous route of challenging mice was shown to be better than intraperitoneal injections. Comparative structural analysis of Cn5 with other toxins of this venom showed that our results are important to be taken into consideration, when choosing appropriate immunogens aimed at the production of better anti-venoms or for the rational design of possible vaccines. 相似文献
73.
A number of neurotoxins from venoms of invertebrates and plants are ligands for voltage-gated Na+ channels and are useful tools for studying Na+ channel function and structure. Using whole-cell recordings from vagal afferent nodose neurons, we studied neurotoxins that target Na+ channels. We asked whether Ts3 (an α-scorpion toxin) and/or veratridine (a lipid-soluble toxin), could modify the TTX-resistant Na+ current generated by vagal afferent nodose neurons. Nodose TTX-resistant current was not affected by Ts3, whereas Ts3 slowed inactivation of the current generated by TTX-sensitive current component. We found that veratridine inhibited the TTX-resistant Na+ currents on rat nodose neurons. Interestingly, veratridine-modified Na+ channels developed a persistent current that accounted for the large tail current observed. We propose that veratridine modifies TTX-resistant Na+ channels through a mechanism distinct from its actions on other voltage-gated Na+ channels. 相似文献
74.
目的 探讨反义端粒酶肽核酸 (PNA)片段对肺癌细胞株端粒酶活性及细胞株生长的抑制作用。方法 将人工合成的端粒酶反义PNA片段 ,应用脂质体转染法将反义端粒酶序列导入肺腺癌细胞株A5 49及小细胞癌细胞株NCI H44 6中 ,采用MTT法检测活细胞数 ,采用RT PCR ELLISA法检测端粒酶活性。结果 转染 72h后 ,A5 49、NCI H 44 6细胞株端粒酶活性 (A45 0值 )分别由 0 .5 82± 0 .0 3 9和 0 .5 71± 0 .0 43降低至 0 .2 94± 0 .0 48(P <0 .0 1)和 0 .2 76± 0 .0 5 1(P <0 .0 1) ;而两细胞株的活细胞数 (A5 80值 )分别由 0 .485± 0 .0 0 9和 0 .5 13± 0 .0 15降低至 0 .191± 0 .0 2 7(P <0 .0 1)和 0 .13 8± 0 .0 46(P <0 .0 1) ,细胞生长受到显著抑制。结论 反义端粒酶PNA片段具有抑制肺癌细胞株端粒酶活性的作用 ,并可抑制肺癌细胞的生长 相似文献
75.
抗百日咳毒素单克隆抗体的纯化及应用研究 总被引:2,自引:0,他引:2
目的纯化抗百日咳毒素(PT)的单克隆抗体(M cAb),并建立特异、准确的PT定量检测方法。方法采用辛酸-硫酸铵沉淀法和A蛋白亲和层析法纯化杂交瘤细胞腹水,并经阻断抑制试验筛选识别不同表位的M cAb,用于建立定量检测PT的ELISA方法。结果经SDS-PAGE分析,纯化M cAb的纯度均在90%以上,选择二株识别不同抗原位点M cAbs,应用于检测PT的双抗夹心ELISA方法,灵敏度为2.14μg/L,批内变异系数5.85%,批间变异系数9.27%,平均回收率为108.12%,应用该法测定了国内几大生产厂家送检的无细胞百日咳疫苗原液中PT含量。结论获得了纯度高的抗PT M cAb,建立了一种特异、准确的定量检测PT的ELISA方法,并用于无细胞百日咳疫苗原液中PT含量的检测,为无细胞百日咳疫苗的质量控制提供了有力的手段。 相似文献
76.
Catharina Wising Jozef Azem Madeleine Zetterberg Liselott A Svensson Karin Ahlman Teresa Lagerg?rd 《Toxicon》2005,45(6):767-776
We investigated the impact of highly purified Haemophilus ducreyi cytolethal distending toxin (HdCDT) on the apoptosis and necrosis of various human cells; including myeloid cells, epithelial cells, keratinocytes, and primary fibroblasts. The levels of apoptosis and necrosis induced in these cells were compared to those induced by HdCDT in human T cells and in the Jurkat T cell line. Levels of caspase-3 activity were measured, and membrane changes like phosphatidylserine (PS) translocation was evaluated after double-staining with the fluorescein isothiocyanate (FITC)-labeled annexin V and propidium iodide (PI) using flow cytometry. HdCDT induced various degrees of apoptosis and necrosis in dose- and time-dependent manners in cells of various lineages. Early and late apoptosis (annexin V-stained cells) were induced in more than 90% of T cells and monocytes after treatment with 100 ng/ml HdCDT for 24 and 48 h, respectively. The corresponding numbers for epithelial cells, keratinocytes, and fibroblasts were 26-32% after treatment with 100 ng/ml HdCDT for 48 h. HdCDT appears to eliminate effectively by inducing apoptosis those cells that are involved in immune responses. Epithelial cells, keratinocytes and fibroblasts, which are important for the healing of chancroid ulcers, are eliminated by apoptosis or necrosis after contact with HdCDT, albeit slower and to a lesser extent than T cells. 相似文献
77.
The blood–brain barrier prevents the entry of many potentially therapeutic peptide drugs to the brain. Glycosylation has shown potential as a methodology for improving delivery to the CNS. Previous studies have shown improved bioavailability and improved centrally mediated analgesia of glycosylated opioids. In this study we investigate the effect of glycosylation on the cyclic opioid peptide [
-Cys2,5,Ser6,Gly7] enkephalin. The peptide was glycosylated on the Ser6 via an O-linkage with various sugar moieties and alignments. The peptides were then investigated for receptor binding, physiochemical attributes, in situ brain uptake in female Sprague–Dawley rats and antinociception in male ICR mice. Glycosylation resulted in a slight decrease in affinity to the δ-opioid receptor, and mixed effect on binding to the μ-opioid receptor. There was a significant decrease in lipophilicity resulting from glycosylation and a slight reduction in binding to bovine serum albumin. In situ perfusion showed that brain uptake was improved by up to 98% for several of the glycosylated peptides, and the nociceptive profiles of the peptides, in general, followed the rank order of peptide entry to the brain with up to a 39-fold increase in A.U.C. 相似文献
78.
In a small number of patients treated with botulinum toxin (BT) antibody (Ab) formation occurs. BT Ab can be detected by the mouse protection assay (MPA) or by the mouse diaphragm assay (MDA). Both methods, however, have major drawbacks. We tested a method for detecting BT Ab which measures the BT-induced reduction in the electromyographic amplitude of the mean maximal voluntary activation (M-EMG) of the sternocleidomastoid muscle. The M-EMG reduction was compared in 17 patients with cervical dystonia and secondary BT therapy failure to the M-EMG reduction previously measured in controls. Values more than 2 SD below the mean of controls were considered abnormal. Six patients showed BT Ab on the MPA and MDA; all of these had abnormal M-EMG reductions. Eleven patients showed no BT Ab on MPA and MDA testing; in ten of these the M-EMG reduction was normal, and in one it was pathological, but MDA testing later changed to positive under continued BT therapy. The sternocleidomastoid test is easy to perform and produces quantitative results. Since its sensitivity and specificity are at least as good as those of the MDA and the MPA, it can replace them. 相似文献
79.
C肽、血脂水平与2型糖尿病下肢血管病变的关系 总被引:4,自引:0,他引:4
目的探讨2型糖尿病患者下肢血管病变的危险因素。方法应用美国GE公司LOG-IQ700型超声诊断仪,对2型糖尿病患者131例下肢动脉进行检测,将下肢血管病变组74例与非下肢血管病变组54例进行对照,记录患者年龄、病程、空腹及餐后血糖、糖化血红蛋白、血脂、空腹及餐后C肽。结果糖尿病下肢血管病变组患者年龄大、病程长、LDL-C明显升高、空腹及餐后C肽明显降低。结论年龄、病程、高血糖、高血脂、低C肽水平是糖尿病下肢血管病变的危险因素,糖尿病神经病变与大血管病变正相关。 相似文献
80.
目的在面瘫患者健侧部分面肌中注射A型肉毒毒素用以矫正口角歪斜和不对称的鼻唇沟,以满足美容的需要。方法将2001年1月 ̄2005年12月来在门诊和住院的部分面瘫患者作为观察对象,除对照组外治疗组分别在健侧面肌中注射A型肉毒毒素,依据注射剂量随机分为5个治疗组:A组(各肌注射1.25U)、B组(各肌注射2.50U)、C组(各肌注射5.00U)、D组(降、提口角肌和颧大、小肌各注射2.50U,笑肌注射5.00U)和E组(降、提口角肌和颧大、小肌各注射5.00U,笑肌注射2.50U),3d后定期观测每例患者双侧口角到门齿中缝的距离差。结果除A组外,各治疗组的口角歪斜和鼻唇沟不对称均得到不同程度的纠正,注射剂量越大起效越快,持续时间越长,但表情动作受到的影响也略大。结论根据口角歪斜和鼻唇沟不对称的程度,在健侧面肌注射相应剂量的A型肉毒毒素,既可以较好地纠正面瘫患者的口角歪斜和鼻唇沟的不对称,又可以避免并发症的发生。 相似文献