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   34649篇
  免费   3570篇
  国内免费   1086篇
耳鼻咽喉   104篇
儿科学   771篇
妇产科学   610篇
基础医学   4205篇
口腔科学   829篇
临床医学   3545篇
内科学   5717篇
皮肤病学   618篇
神经病学   2003篇
特种医学   584篇
外国民族医学   4篇
外科学   2227篇
综合类   5056篇
现状与发展   2篇
预防医学   2091篇
眼科学   442篇
药学   5618篇
  40篇
中国医学   2828篇
肿瘤学   2011篇
  2024年   119篇
  2023年   816篇
  2022年   1094篇
  2021年   2047篇
  2020年   1938篇
  2019年   1687篇
  2018年   1507篇
  2017年   1702篇
  2016年   1561篇
  2015年   1448篇
  2014年   2230篇
  2013年   2830篇
  2012年   1797篇
  2011年   1969篇
  2010年   1538篇
  2009年   1317篇
  2008年   1308篇
  2007年   1302篇
  2006年   1225篇
  2005年   1031篇
  2004年   936篇
  2003年   847篇
  2002年   726篇
  2001年   591篇
  2000年   499篇
  1999年   327篇
  1998年   363篇
  1997年   325篇
  1996年   293篇
  1995年   264篇
  1994年   282篇
  1993年   244篇
  1992年   239篇
  1991年   220篇
  1990年   194篇
  1989年   185篇
  1988年   146篇
  1987年   169篇
  1986年   115篇
  1985年   358篇
  1984年   274篇
  1983年   243篇
  1982年   212篇
  1981年   189篇
  1980年   141篇
  1979年   93篇
  1978年   85篇
  1977年   65篇
  1976年   51篇
  1975年   39篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
本文介绍正常人113名,肺部恶性病变49例及肺部良性病变33例的血清LSA测定结果,正常人血清LSA含量平均值为0.1243±0.0358g/L。特异性97.40%,男女间无差异,48例肺癌血清LSA平均值0.2698±0.0915g/L,敏感性85.40%;33例良性病变LSA平均值0.1712±0.0767g/L,特异性78.79%。肺癌患者血清LSA较良性病变明显升高,故测定血清LSA对鉴别良恶性病变有一定价值。  相似文献   
112.
The chemokines, macrophage inflammatory protein-1 (MIP-1) and its subunit MIP-1β, induce an intense fever in the rat when they are injected directly into the anterior hypothalamic, pre-optic area (AH/POA), a region containing thermosensitive neurons. The purpose of this study was to compare the central action on body temperature (Tb) of MIP-1β with that of interleukin-6 (IL-6), which also has been implicated in the cerebral mechanism underlying the pathogenesis of fever. Following the stereotaxic implantation in the AH/POA of guide cannulae for repeated micro-injections, radio transmitters which monitor Tb continuously were inserted intraperitoneally in each of 15 male Sprague-Dawley rats. Each micro-injection was made in a site in the AH/POA in a volume of 1.0 μl of pyrogen-free artificial CSF, recombinant murine MIP-1β, or recombinant human IL-6. MIP-1β in a dose of 25 pg evoked an intense fever characterized by a short latency, a mean maximum rise in Tb of 2.4 ± 0.21°C reached by 3.7 ± 0.42 hr, and a duration exceeding 6.5 hr. Injected into homologous sites in the AH/POA, IL-6 induced a dose dependent fever of similar latency and a mean maximal increase in Tb of 1.2 ± 0.25°C, 1.8 ± 0.15°C, and 2.1 ± 0.22°C and duration of 6.2 ± 1.28 hr, 6.7 ± 0.49 hr, and 6.8 ± 0.65 hr when given in doses of 25, 50, and 100 ng, respectively. These results show that MIP-1β and the highest dose of IL-6 induce a fever of comparable intensity, but MIP-1β exerts its action in a much lower concentration. Thus, the de novo synthesis and subsequent action of the MIP-1 family of cytokines on neurons of the AH/POA in response to a pyrogen challenge apparently play a functional role in the pathogenesis of fever. Further, the endogenous activity of IL-6 in the hypothalamus which is enhanced in response to a lipopolysaccharide also may reflect its essential part in the acute phase response to a bacterial challenge. Copyright © 1994 Wiley-Liss, Inc.  相似文献   
113.
In a prospective, controlled, randomized study where two differentagonists were used, we compared three different long desensitizationprotocols for induction of multiple follicular growth in medicallyassisted conception cycles. In protocol A, 30 patients wereinjected with buserelin twice a day for 15 days prior to ovarianstimulation until human chorionic gonadotrophin (HCG) administration.In protocol B, 30 patients were injected with a single doseof long acting Triptorelin (3.75mg) 15 days before the ovarianstimulation onset. In protocol C, 30 patients were injectedwith the long acting Triptorelin 4 weeks before ovarian stimulationfollowed by daily administration of 0.1 mg of the same agonistuntil HCG injection. There was no difference in the ovarianresponse to exogenous gonadotrophin stimulation, except forthe presence of premature luteinization in two patients in groupB. A significantly higher number of mature oocytes was collectedfrom patients with protocol A; however, the fertilization andcleavage rate demonstrated no significant difference among thethree groups of patients. The ongoing pregnancy rate and theimplanation rate per treatment cycle were very similar in thethree study groups. When the convenience, cost and side-effectsfor the patient are being considered, protocol B should be selectedas the first choice when the agonist is utilized for the purposeof inducing pituitary desensitization before and during ovarianstimulation.  相似文献   
114.
肺部炎性假瘤20例,其中1例肺癌误诊为炎性假瘤,2例肺炎性假瘤与肺癌并存。炎性假瘤病灶多为单发,分布在两侧不同肺野内,可分为圆结节、不规则形、弥漫浸润及肺不张型。重点讨论本病诊断及外科治疗体会。  相似文献   
115.
血钙水平与肾癌肿瘤大小、分期的相关性分析   总被引:2,自引:0,他引:2  
目的分析肾细胞癌患者血钙水平和肿瘤大小与分期的相关性,从而进一步发现与病情相关的规律和了解病情。方法按照血钙水平将肿瘤大小/分期相应地分3组,即降低、正常和升高各3组。利用SPSS10.0软件,对3组不同的肿瘤大小/分期病例进行差异性分析和相关性研究。结果3组不同的肿瘤大小差异性分析(Kruskal-wallisH)显示,X^2=4.768,df=2,P=0.092;Spearman相关分析显示相关系数为.0.166,P=0.029。3组不同的肿瘤分期差异性分析(Kruskal-Wallis H)显示,X^2=4、277,df=2,P=0.118;Spearman相关系数为.0.157,P=-0.039。结论3组不同的肿瘤大小之间差异性无统计学意义,血钙水平与肿瘤大小间存在负相关;3组不同的肿瘤分期之间差异性无统计学意义,血钙水平与肿瘤分期间存在负相关。  相似文献   
116.
蔺小倩 《青海医药杂志》2003,33(9):15-16,T003
目的:探讨肺炎性假瘤的病理类型和临床特点;方法:根据1988年(HUNPATHOL)MATSUBRA等分型方法,对50例肺炎性假瘤进行临床病理分析;结果:机化肺炎型23例,纤维组织细胞型16例,淋巴浆细胞型11例;结论:肺炎性假瘤其性质均为良性,男性多于女性,共同的病理特点是纤维母细胞增生、血管增生,组织细胞、淋巴细胞、浆细胞浸润,肺泡细胞增殖。  相似文献   
117.
An automated measurement of total and free hydroxyproline in serum or urine is presented that uses flow injection analysis. After exclusion of nonspecific substances, hydroxyproline was oxidized by chloramine- T and L-cysteine with Ehrlich's reagent. The linearity obtained was from 3.8μmole/ L to 1.22 mmole/L with good precision (CV <3%). Comparison of the proposed method with HPLC yielded r = 0.939 as the correlation coefficient. Reference intervals of free and total hydroxyproline are 1.4–9.7 μmole/L, 3.8–27.2 μmole/L for serum, and 10.0–72.5 μmole/L, 25.2–303.6 μmole/L for urine, respectively. Serum free and total hydroxyproline levels in renal osteodystrophy patients on maintenance hemodialysis (N = 71) were significantly higher than in controls (P<0.0001). This method is superior to the use of HPLC with regard to stability of the color reaction. The measurement of serum free and total hydroxyproline is a useful marker for therapeutic observation of renal osteodystrophy patients. © 1994 Wiley-Liss, Inc.  相似文献   
118.
目的:测定妊高征患者血清睾酮水平并探讨其临床意义。方法:采用放射免疫分析法测定妊高征患者30例、正常孕妇20例血清及其新生儿脐血睾酮水平。结果:妊高征患者血清睾酮水平(0.153±0.078nmol/L)明显高于正常孕妇组(0.023±0.015nmol/L),有显著性差异(P<0.001)。妊高征组脐血睾酮水平(0.052±0.041nmol/L)低于正常孕妇组(0.119±0.059nmol/L),有显著性差异(P<0.05),两组睾酮水平与新生儿性别无关(P>0.05)。结论:孕妇血清睾酮在妊高征的病理生理中起调节或加强作用。  相似文献   
119.
120.
Background and Aims: Chemokines and their receptors have recently been shown to have major roles in cancer metastasis. The aim of this study was to determine whether the interaction between chemokine receptor 6 (CCR6) and its ligand, macrophage inflammatory protein‐3 alpha (MIP‐3α), correlates with metastasis of hepatocellular carcinoma (HCC). Methods: To observe the reaction of CCR6 expressed cancer cells to MIP‐3α stimulation, chemotactic and actin polymerization assays for both CCR6 high cells (HepG2) and CCR6 low cells (MCF‐7) were performed. CCR6 mRNA levels in tumor specimens from 30 HCC patients were quantified by real‐time polymerase chain reaction. Patients were classified into two groups, high (≥ 20 copies; n = 10) CCR6 and low (<20 copies; n = 20) CCR6 on the basis of CCR6 expression, and the groups were compared with respect to clinicopathological features. Results: When HepG2 cells (CCR6 high) were stimulated with MIP‐3α, they migrated in a dose‐dependent manner, and formation of pseudopodia was observed. These phenomena were not observed in the CCR6 low cells. The incidence of intrahepatic metastasis was higher in the high CCR6 expression group than in the low CCR6 expression group (P < 0.05). Disease‐free survival was significantly poorer in the high CCR6 expression group than in the low CCR6 expression group (P < 0.05). Conclusions: It was indicated that CCR6 might be associated with intrahepatic metastasis of HCC and might be able to become one of the prognostic factor after hepatic resection for HCC.  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