全文获取类型
收费全文 | 125805篇 |
免费 | 10387篇 |
国内免费 | 6467篇 |
专业分类
耳鼻咽喉 | 1178篇 |
儿科学 | 2068篇 |
妇产科学 | 1391篇 |
基础医学 | 13286篇 |
口腔科学 | 2226篇 |
临床医学 | 15631篇 |
内科学 | 17484篇 |
皮肤病学 | 1960篇 |
神经病学 | 5892篇 |
特种医学 | 4809篇 |
外国民族医学 | 29篇 |
外科学 | 11808篇 |
综合类 | 22567篇 |
现状与发展 | 23篇 |
一般理论 | 9篇 |
预防医学 | 11117篇 |
眼科学 | 2928篇 |
药学 | 13071篇 |
87篇 | |
中国医学 | 6610篇 |
肿瘤学 | 8485篇 |
出版年
2024年 | 246篇 |
2023年 | 1146篇 |
2022年 | 2932篇 |
2021年 | 4092篇 |
2020年 | 3067篇 |
2019年 | 2832篇 |
2018年 | 2946篇 |
2017年 | 3039篇 |
2016年 | 3154篇 |
2015年 | 4845篇 |
2014年 | 6306篇 |
2013年 | 6886篇 |
2012年 | 10156篇 |
2011年 | 10786篇 |
2010年 | 8164篇 |
2009年 | 7063篇 |
2008年 | 8444篇 |
2007年 | 8373篇 |
2006年 | 7821篇 |
2005年 | 7032篇 |
2004年 | 5648篇 |
2003年 | 5656篇 |
2002年 | 4529篇 |
2001年 | 3658篇 |
2000年 | 2903篇 |
1999年 | 2063篇 |
1998年 | 1054篇 |
1997年 | 1105篇 |
1996年 | 809篇 |
1995年 | 699篇 |
1994年 | 572篇 |
1993年 | 400篇 |
1992年 | 569篇 |
1991年 | 499篇 |
1990年 | 436篇 |
1989年 | 369篇 |
1988年 | 336篇 |
1987年 | 288篇 |
1986年 | 250篇 |
1985年 | 235篇 |
1984年 | 159篇 |
1983年 | 133篇 |
1982年 | 99篇 |
1981年 | 91篇 |
1980年 | 70篇 |
1979年 | 99篇 |
1978年 | 86篇 |
1976年 | 47篇 |
1974年 | 57篇 |
1973年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
目的 :进一步探讨 MRI增强前后的准备与护理方法。材料与方法 :共增强 833例 ,男 5 85例 ,女 2 4 8例。使用顺磁性造影剂 Gd- DTPA,按 0 .2 m L/kg体重给药。其中双倍量增强 110例 ,增强前认真履行告知义务和签署同意书。发生造影剂外漏者给予鲜马铃薯片外敷。结果 :增强效果达良好以上共 82 5例 ,占 99% ,未发生严重负反应。 3例造影剂外漏 ,鲜马铃薯片外敷后 3h痊愈。结论 :增强前充分细致的准备是保证增强效果的重要因素。认真履行告知义务和签置同意书 ,不仅尊重了病人的权利 ,也是依法行医 ,保证医疗安全的需要 相似文献
62.
The authors performed a study of intraocular pressure-dependent changes in optic disc cupping in 17 adults with chronic open-angle glaucoma. Analyses with the Rodenstock Optic Nerve Head Analyzer were performed at baseline low intraocular pressure during therapy, after elevation of intraocular pressure (from therapeutic failure or noncompliance), and after reduction of intraocular pressure with successful therapy. Optic disc cupping increased significantly upon short-term increase of intraocular pressure from baseline of 20.4 +/- 2.5 mmHg to 31.1 +/- 5.9 mmHg. Optic disc cupping reverted to baseline after persistent intraocular pressure reduction to 19.3 +/- 4.8 mmHg. These data demonstrate intraocular pressure-dependent dynamic changes of optic disc cupping in patients with demonstrable glaucomatous optic nerve damage. They underscore the detrimental effect of elevated intraocular pressure and the beneficial effect of intraocular pressure reduction on optic disc cup changes. 相似文献
63.
环氧合酶-2和血管内皮生长因子共表达与肝细胞癌血管形成的关系 总被引:7,自引:6,他引:1
目的 探讨环氧合酶 (COX) 2与肝细胞癌血管形成的关系。方法 利用免疫组织化学、Westernblot方法检测 48例肝癌组织中COX 2和血管内皮生长因子 (VEGF)蛋白及逆转录 聚合酶链反应法 (RT PCR)检测COX 2和VEGFmRNA的共表达 ,对共表达COX 2和VEGF蛋白和mRNA的肝癌组织进行微血管记数。结果 免疫组织化学检测中 ,48例肝癌组织 3 6例共表达COX 2和VEGF蛋白。类似结果见于蛋白电泳分析。RT PCR显示 ,48例肝癌组织 3 6例共表达COX 2mRNA和VEGFmRNA。两者之间的表达明显相关 (γ =0 .845 )。共表达COX 2和VEGF蛋白和mRNA的肝癌组织中 ,平均微血管数 (5 6.8± 17.5 )个 ,明显高于阴性表达组。结论 COX 2可能与肝细胞癌的血管形成有关 ,且其作用之一可能是通过上调VEGF通道来发挥的 相似文献
64.
Jen Te Hsu Chi Ming Chu Shih Tai Chang Hui Wen Cheng Nye Jan Cheng Wan-Ching Ho Chang Min Chung 《Circulation journal》2006,70(12):1611-1616
BACKGROUND: This study investigated the utility of the alveolar - arterial oxygen pressure difference (AaDO (2)) in predicting the short-term prognosis of acute pulmonary embolism (PE). METHODS AND RESULTS: This study retrospectively enrolled 114 consecutive patients with acute PE, diagnosed by either spiral computed tomography or high probability ventilation - perfusion lung scans. During the first 24 h of admission, all patients had initial artery blood gas collected under room air. Patient exclusion criteria were chronic lung disease, septic emboli, and moderate and low probability lung scans. Patients were assigned to 2 groups based on either 30-day death or a 30-day composite event. Receiver operating characteristic analyses was used to determine the AaDO(2) cut-off value for predicting primary and composite endpoints. Statistical analysis demonstrated significant differences in AaDO(2) between the 30-day composite endpoint group and the 30-day composite event-free survival group (p=0.012). The AaDO(2) had a strong trend between the 30-day death group and the survival group (p=0.062). The best cut-off value for AaDO(2) was 53 mmHg and using this, the positive predictive value for 30-day death was 25% and the negative predictive value was 92%. For the 30-day composite endpoint, the positive predictive value for AaDO(2) was 35%, and the negative predictive value was 84%. In this study, thrombocytopenia was also an indicator of poor prognosis for patients with acute PE. CONCLUSION: The AaDO(2) measurement is a highly useful and simple measurement for predicting short-term prognosis in patients with acute PE. It has high negative predictive value and moderate positive predictive value for 30-day death and 30-day composite event. Aggressive thrombolytic treatment strategies should be considered for patients with an initial poor prognostic parameter (ie, AaDO(2) >or=53 mmHg). 相似文献
65.
椎管内原发性孤立性纤维性肿瘤临床病理观察(附2例报告) 总被引:1,自引:0,他引:1
目的探讨椎管内孤立性纤维性肿瘤的临床病理特征、诊断和鉴别诊断,以期提高对该肿瘤的诊断水平。方法复习2例椎管内原发性孤立性纤维性肿瘤的临床资料,并观察其组织学特征和免疫组化标记。结果2例患者男、女各1例,年龄分别为23岁和32岁,临床表现为局部神经压迫症状。MRI示椎管内髓外硬膜内占位。组织学特征为梭形、卵圆形细胞呈束状、波浪状或旋涡状排列,富于胶原纤维及伴有分支状薄壁血管。细胞未见异型性和核分裂像。免疫组化示瘤细胞Vimentin( ),CD34( ),CD99( ),Bcl-2( ),AACT(-),Actin(-),S-100(-),EMA(-),GFAP(-),CD68(-),CD117(-),SMA(-),NF(-)。结论椎管内原发性孤立性纤维性肿瘤是一种罕见的肿瘤,诊断主要依靠病理形态学及免疫组化,并应与椎管内的其他梭形细胞肿瘤鉴别。 相似文献
66.
Inhibition of the N and L type Ca2+ channels with omega conotoxin GVIA (omega-CgTx) together with the dihydropyridine (-)-202-791 produces slight reduction (congruent to 25%) of K(+)-evoked Ca2+ influx in mammalian synaptosomes. These results and others suggest the existence of a third high threshold voltage sensitive calcium channel (VSCC) responsible for the majority of influx. Venom from the funnel web spider Hololena curta potently and persistently inhibited Ca2+ influx in rat cortical synaptosomes (IC50 1:10,000 or 4.21 micrograms/venom protein/ml of synaptosomes). Also Ca2+ influx in cerebellar synaptosomes was inhibited in a similar manner. K(+)-evoked tritium release from synaptosomes labeled with [3H]noradrenaline was inhibited by Hololena venom (congruent to 60% reduction at 10 micrograms/venom protein). Inhibition of Ca2+ influx by venom was unaffected by combined omega-CgTx and (-)-202-791 pretreatment (both 1 microM). Hololena venom and its active constituent should provide useful tools to investigate the role of this novel Ca2+ channel in neuronal function. 相似文献
67.
On the basis of the common occurrence of high concentration of estrogen and activated macrophages in patients with endometriosis, we postulate that interaction between 17beta-estradiol and macrophage may be an important affair in endometriosis. So our study was focused on the effect of 17beta-estradiol on macrophage. First morphology of macrophages was examined with environmental scanning electron microscopy. Increased size, extension of more microvilli, expression of retraction fibers and elaboration of membrane ruffles were detected in 17beta-estradiol treated macrophages. Then Nitrate and nitrite level in the supernatant was measured by the method of Griess and iNOS expression was analyzed using immunohistochemical staining. It showed that 17beta-estradiol could induce NO release from peritoneal macrophages and expression of iNOS was increased. Also more TNF-alpha in supernatant that was measured by MTT via L929 cell was produced by macrophages under the inducing of 17beta-estradiol. Furthermore, [Ca2+]i, which was viewed by microscope in a laser scanning confocal unit, elevated 39.8% in peritoneal macrophages after 17beta-estradiol 100 nmol/L treated. The results above demonstrated that peritoneal macrophage had been activated in both morphology and cytokine line when interaction with 17beta-estradiol, which indicated that macrophage activated by 17beta-estradiol might play a permission role in development of endometriosis. 相似文献
68.
端粒酶在鳞状细胞癌和Bowen病组织中的表达 总被引:2,自引:2,他引:0
目的探讨端粒酶在皮肤鳞状细胞癌(SCC)及Bowen病(BD)病变组织中的表达及其临床意义。方法应用原位杂交方法检测30例皮肤SCC和30例BD病变组织中端粒酶基因hTR和hTERTmRNA的表达。结果在BD组织中hTR和hTERTmRNA呈弱表达,阳性率为23.33%和16.67%。在SCC中,hTR和hTERTmRNA的阳性率分别为86.67%和93.33%。其中Ⅰ、Ⅱ级SCC阳性率分别为82.35%和88.24%,无强阳性;Ⅲ、Ⅳ级SCC阳性率分别为92.31%和100%、强阳性表达率分别为69.23%和76.92%。SCC和BD两者比较差异有显著性(P<0.05)。SCCⅠ、Ⅱ级与Ⅲ、Ⅳ级比较差异有显著性(P<0.05)。结论端粒酶hTR和hTERTmRNA的表达增多是预测皮肤SCC的重要因素。 相似文献
69.
一日,我接到一位女土的咨询电话,她希望我能解释一下为什么每次过性生活时,丈夫射精她没有感觉.这是一个有关提高夫妻性爱质量的问题. 一般来说,夫妻在做爱过程中,丈夫射精妻子都会有所感觉.要么妻子感到丈夫急促的喘气声,身体激烈地晃动,小腹有紧张感;要么妻子感到阴道中有一股液体暖流;要么妻子的阴道口出现收缩感,随之带来快感乃至达到性高潮妻子在丈夫射精时没感觉,一般表现为以下几种情况. 相似文献
70.
C-Y Chu 《Journal of the European Academy of Dermatology and Venereology》2007,21(4):484-490
BACKGROUND: Steroid-induced rosacea-like eruption is characterized by facial rosacea-like dermatitis in patients that have been treated with topical steroids for relatively long periods. OBJECTIVE: To evaluate the efficacy and tolerability of 1% pimecrolimus topical cream for steroid-induced rosacea-like eruption. METHODS: In an open-label pilot study, 40 patients were enrolled and instructed to apply 1% pimecrolimus cream twice daily for 6 weeks. Patients were evaluated by a rosacea clinical score, investigator's global assessment, overall erythema severity, and tolerability at weeks 0, 2, and 6. RESULTS: In 35 patients, the rosacea clinical score decreased significantly from 16.0+/-4.3 at baseline to 8.1+/-3.3 at week 2 and 4.2+/-2.5 at week 6 (P<0.0001). Investigator's global assessment was 4.1+/-1.1 (baseline), then decreased to 1.4+/-0.8 (week 2) and 0.5+/-0.6 (week 6) (P<0.0001). By week 6, 48.6% of the patients were clear. Overall erythema severity was 2.4+/-0.7 (baseline), 0.9+/-0.4 (week 2), and 0.3+/-0.4 (week 6) (P<0.0001). Cutaneous adverse events (local burning, stinging, and itching) occurred in 17.5%. CONCLUSION: Pimecrolimus cream might be efficacious, safe, and well tolerated for steroid-induced rosacea-like eruption. The small sample size and open label nature of this study is its limitation. Further double-blind, vehicle-controlled studies are needed. 相似文献