首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   27147篇
  免费   3258篇
  国内免费   2006篇
耳鼻咽喉   176篇
儿科学   310篇
妇产科学   249篇
基础医学   3011篇
口腔科学   635篇
临床医学   3847篇
内科学   3608篇
皮肤病学   312篇
神经病学   1332篇
特种医学   978篇
外国民族医学   24篇
外科学   2641篇
综合类   4938篇
现状与发展   6篇
一般理论   3篇
预防医学   2225篇
眼科学   652篇
药学   2993篇
  50篇
中国医学   2239篇
肿瘤学   2182篇
  2024年   171篇
  2023年   682篇
  2022年   1621篇
  2021年   1898篇
  2020年   1470篇
  2019年   1184篇
  2018年   1138篇
  2017年   1119篇
  2016年   1035篇
  2015年   1495篇
  2014年   1695篇
  2013年   1610篇
  2012年   2018篇
  2011年   2236篇
  2010年   1469篇
  2009年   1267篇
  2008年   1409篇
  2007年   1299篇
  2006年   1219篇
  2005年   1157篇
  2004年   723篇
  2003年   692篇
  2002年   576篇
  2001年   418篇
  2000年   428篇
  1999年   447篇
  1998年   265篇
  1997年   274篇
  1996年   172篇
  1995年   181篇
  1994年   151篇
  1993年   92篇
  1992年   107篇
  1991年   88篇
  1990年   99篇
  1989年   74篇
  1988年   92篇
  1987年   56篇
  1986年   48篇
  1985年   33篇
  1984年   14篇
  1983年   16篇
  1981年   13篇
  1979年   19篇
  1977年   10篇
  1975年   11篇
  1974年   10篇
  1973年   15篇
  1969年   14篇
  1966年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
丹参和透明质酸钠注射液对骨性关节炎治疗作用的实验研究   总被引:22,自引:0,他引:22  
采取家兔膝关节制动方法建立骨性关节炎动物模型,用丹参注射液和透明质酸钠注射液关节腔内注射进行治疗,分别在制动后3、6、9周测量关节活动度,取关节软骨制成标本经光镜和透射电镜观察。结果显示,与单纯制动组比较,丹参治疗组和透明质酸钠治疗组的关节活动度明显改善,关节病变出现晚,程度轻,以早期最明显。表明丹参和透明质酸钠具有延缓和减轻关节退变的作用,对骨性关节炎早期有一定的治疗作用。  相似文献   
82.
83.
84.
观察EGF-PE40重组毒素对喉鳞癌细胞的毒性作用,为寻找新型的治疗头颈鳞癌的生物制剂奠定基础。应用MTT比色法测定EGF-PE40重组毒素的生物学活性。并在光镜下观察Hep-2细胞形态变化。确定MTT比色法中Hep-2细胞浓度为2×104/well。选择10%SDS-0.01mol/LHCI作为MTT结晶的溶解液,当EGF-PE40重组毒素为0.53ng/ml时,50%的Hep-2细胞死亡,在一定范围内,随重组毒素增加,细胞损伤加重。  相似文献   
85.
Objective To evaluate the feasibility and indication of laparoscopie duodenoduoden-ostorny for neonates with congenital duodenal obstruction- Methods From May 2004 to Feburary 2008,6 newborns with duodenal obstruction underwent exploratory laparoscopy. With a lower-pressure pneumoperitoneum of 5~8 mmHg and a suspending suture for right liver elevator, the procedure was performed using 3 cannulas of 3.3 mm to 5.5 mm diameter. Under the laparoscopic vision, the cause of duodenal obstruction was diagnosed and a sutured anastomosis was performed after the duodenum mo-bilized. Results Findings at laparoscopy included duodenal diaphragm in 3 cases,annular pancreas in 2 cases, and preduodenal portal vein in 1 case. Three cases with duodenal diaphragmatic stenosis were en-countered a partial excision of the diaphragm after vertical incision of the anterior part of duodenum followed laparoscopically by a transverse suture. A diamond-shaped side-to-side duodenoduodenal anas-tomosis was successfully carried out in 2 cases of annular pancreas through a laparoseopic approach, but a duodenojejunostomy was converted to mini-laparotomy during the laparoscopic course of a predu-odenal portal vein. The average operative time was 102 16.5 min (85~135 min). Visualization was ex-cellent, and there were no intraoperative complications. Feedings were started on postoperative day 3 to 5. All cases were on full feedings after 8 to 10 days. Follow-up upper gastrointestinal tests showed no evidence of stricture or obstruction. Conclusions The duodenoduodenostomy with laparoseopy can be performed in neonates securely and appropriated for a full-term newborn with tolerance CO2 pneumo-peritoneum. It provides an excellent and micro-invasive way to evaluate and treat congenital duodenal obstruction.  相似文献   
86.
Objective: The mainstay treatment of esophageal squamous cell carcinoma(ESCC) involves chemotherapy and immunotherapy. However, alternative therapies are required for patients who are refractory or intolerant to existing therapies.Methods: In this single-arm, multicenter, open-label phase Ib study, 30 patients received an intravenous infusion of SCT200, an antiepidermal growth factor receptor(EGFR) monoclonal antibody, 6.0 mg/kg once a week for 6 weeks, followed by 8.0 mg/kg once every 2 weeks u...  相似文献   
87.

Purpose

Every year, almost one million individuals are diagnosed with hepatocellular carcinoma (HCC) worldwide and more than 690,000 patients die of it. At present, most therapeutic anti-HCC agents are not effective, which is due to the appearance of chemo-resistance and/or toxic side effects. Therefore, it is imperative to find novel more effective anti-HCC agents. Here, we evaluated the effect of giganteaside D (GD), an oleanolic acid saponin from P. scabiosaefolia, on the growth and apoptosis of HCC cells.

Methods and results

Using MTT and clonogenic assays, we found that GD exhibited a significant growth inhibitory effect on the HCC-derived cell lines HepG2 and Bel-7402. In addition, we found that GD induced mitochondria-mediated apoptosis in these HCC-derived cells, as indicated by a decreased mitochondrial potential, activation of Caspase-9 and Caspase-3, cleavage of PARP and release of Cytochrome C from the mitochondria. Besides, we found that GD stimulated the generation of reactive oxygen species (ROS) and that blockage of ROS attenuated the GD-induced mitochondria-mediated apoptosis. Additionally, we found that GD treatment led to a decrease in phosphorylated Erk (p-Erk) and triggered the generation of p-JNK, both components of the mitogen-activated protein kinase (MAPK) signaling pathway. Inhibition of Erk or JNK by specific inhibitors or siRNAs augmented or attenuated the cytotoxic and apoptotic effects of GD.

Conclusions

From our results we conclude that GD can induce ROS-mediated apoptosis in HCC-derived cells through the MAPK pathway. This observation may open up avenues to explore the future use of GD as a HCC chemotherapeutic agent.
  相似文献   
88.
目的探讨脑梗死患者颈动脉粥样硬化性斑块与超敏C-反应蛋白(Hs-CRP)含量的关系。方法分别测定30名通过颈动脉超声检查发现有粥样硬化斑块的急性脑梗死(A组)、脑供血不足患者(B组)和无颈动脉粥样硬化斑块老年健康体检者(C组)血清中Hs-CRP含量。结果A组Hs-CRP含量明显高于B组和C组(P〈0.05);而B组和C组之间无显著性差异。结论Hs-CRP与动脉硬化引起的急性脑梗死有关,Hs-CRP与稳定性颈动脉硬化性斑块患者的脑供血不足的症状无关。  相似文献   
89.
In this work, an aptasensor based on a portable U-disk electrochemical workstation in combination with a screen-printed electrode (SPE) is demonstrated for the quantitative determination of zearalenone (ZEN). The aptamer is immobilized on Au NPs@Ce-TpBpy COF (Covalent organic frameworks), which is modified on the surface of glassy carbon electrode. ZEN specifically binds to ZEN aptamer, which hinders the electron transfer and decreases the catalytic current of Au NPs@Ce-TpBpy COF for the reduction of hydrogen peroxide, measured by chronoamperometry (it). The quantitative detection of ZEN toxin is realized by a decrease of the catalytic current (ΔI). Under the optimal experimental conditions, the aptamer sensor exhibited excellent sensitivity, selectivity, reproducibility. A wide linear range of 1 pg mL−1–10.0 ng mL−1 with a detection limit of 0.389 pg mL−1 (at 3σ) was obtained. The linear equation is ΔI = 0.401 lg c + 1.948 with a correlation coefficient of 0.9906. The recovery is in the range of 93.0–104.7% for the cornflour samples. The proposed method offers a new strategy for the rapid, inexpensive, and real-time detection of ZEN.

An aptasensor based on a portable U-disk electrochemical workstation is demonstrated for the quantitative determination of zearalenone. The aptamer sensor exhibited excellent sensitivity, selectivity, reproducibility.  相似文献   
90.
目的 探索初治慢性乙型肝炎(CHB)患者外周血中细胞因子表达水平及其与病毒载量和肝脏炎症程度的关系,以期为临床动态评估病情和预后方面提供新思路。方法 选择2018年10月至2019年11月就诊于海军军医大学第一附属医院感染科的初治慢性乙型肝炎病毒(HBV)感染者68例,健康对照者12名,通过ELISA检测外周血中细胞因子IL-17A、IL-2、IL-21和IL-4表达水平,同时检测HBV DNA及转氨酶水平。统计学处理采用Mann-Whitney U检验、Kruskal-Wallis H检验及Spearman相关性分析。结果 相较于健康对照者,初治CHB患者外周血IL-17A高 [17.50(11.99,25.36)vs14.14(9.01,23.68)pg/ml,Z=-2.001,P=0.045],IL-2低[57.19(31.10,79.92)vs73.06(62.41,105.84)pg/ml,Z=-2.509,P=0.012],IL-21高[37.12(23.85,77.66)vs(20.95±5.72)pg/ml,Z=-3.485,P<0.01],IL-4表达水平无差异。不同免疫状态的IL-17A表达有明显差异(H=8.870,P=0.031)。炎症活动状态CHB患者的IL-17A和IL-21更低、IL-2更高(P<0.05),IL-4无差异(P>0.05)。HBeAg阳性CHB患者、HBeAg阴性CHB患者与健康对照者外周血细胞因子IL-17A、IL-2、IL-21比较,差异有统计学意义(IL-17A:H=10.061,P=0.007;IL-2:H=6.576,P=0.037;IL-21:H=12.444,P=0.002)。初治CHB患者外周血IL-17A、IL-21、IL-4与HBV DNA无相关性(r=0.02、0.23、0.07,均P>0.05),IL-2与HBV DNA存在弱相关(r=0.32,P=0.01)。初治HBV患者外周血IL-17A、IL-21与ALT存在相关性(IL-17A:r=0.59,P<0.01;IL-21:r=0.49,P<0.01),与AST存在相关性(IL-17A:r=0.47,P<0.01;IL-21:r=0.36,P<0.01),而IL-2、IL-4与ALT和AST均无明显相关。ALT≥300U/L的初治CHB组、ALT<300U/L的初治CHB组与健康对照者外周血细胞因子IL-17A、IL-2、IL-21比较,差异有统计学意义(IL-17A:H=27.557,P<0.01;IL-2:H=8.581,P=0.014;IL-21:H=21.438,P<0.01)。ROC曲线分析结果显示,IL-17A判断肝脏炎症程度的AUC值为0.8933(95%CI:0.7930-0.9936),IL-21判断肝脏炎症程度的AUC值为0.7600(95%CI:0.6227-0.8973)。结论 IL-17A、IL-2和IL-21参与慢性HBV感染进程:初治CHB患者无论HBeAg阳性与否或炎症程度高低,外周血IL-17A和IL-21升高,IL-2下降;IL-2与HBV DNA有一定相关性;IL-17A和IL-21与ALT及AST均存在正相关;检测IL-17A和IL-2有助于病情评估与预后判断。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号