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   17905篇
  免费   1747篇
  国内免费   386篇
耳鼻咽喉   60篇
儿科学   1758篇
妇产科学   277篇
基础医学   1955篇
口腔科学   158篇
临床医学   1189篇
内科学   2865篇
皮肤病学   169篇
神经病学   871篇
特种医学   179篇
外科学   984篇
综合类   2750篇
现状与发展   2篇
预防医学   1843篇
眼科学   272篇
药学   757篇
  10篇
中国医学   3738篇
肿瘤学   201篇
  2024年   100篇
  2023年   345篇
  2022年   754篇
  2021年   1045篇
  2020年   949篇
  2019年   676篇
  2018年   614篇
  2017年   798篇
  2016年   758篇
  2015年   656篇
  2014年   1201篇
  2013年   1143篇
  2012年   937篇
  2011年   1006篇
  2010年   729篇
  2009年   661篇
  2008年   604篇
  2007年   650篇
  2006年   616篇
  2005年   504篇
  2004年   469篇
  2003年   418篇
  2002年   337篇
  2001年   325篇
  2000年   301篇
  1999年   271篇
  1998年   265篇
  1997年   219篇
  1996年   186篇
  1995年   215篇
  1994年   179篇
  1993年   173篇
  1992年   159篇
  1991年   174篇
  1990年   148篇
  1989年   145篇
  1988年   143篇
  1987年   117篇
  1986年   118篇
  1985年   152篇
  1984年   116篇
  1983年   74篇
  1982年   109篇
  1981年   92篇
  1980年   69篇
  1979年   79篇
  1978年   45篇
  1977年   43篇
  1976年   49篇
  1975年   28篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
The incidence (%) of hyperbilirubinemia (serum bilirubin ≥257 μmol/l) was similar in neonates with a combination of ABO incompatibility and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (45%), with ABO incompatibility (54%) or G-6-PD deficiency (37%), alone (ns). Carboxyhemoglobin values, corrected for inspired CO, were similarly elevated in all three groups (0.87 ± 0.32%, 0.82 ± 0.29%, 0.76 ± 0.18%, respectively, ns), but correlated with bilirubin only in those with ABO incompatibility alone. ABO-incompatible/G-6-PD-deficient neonates, compared with those with either condition alone, are not at increased risk for hemolysis or hyperbilirubinemia.  相似文献   
42.
The harsh treatment of former prisoners of war (POWs) of World War II and the Korean conflict resulted in severe malnutrition. Although rarely linked to specific long-term medical problems, a specific marker of malnutrition, self-reported lower limb edema (presumably due to a vitamin B deficiency) was associated with a three-fold increase in subsequent death attributed to ischemic heart disease (IHD) during the follow-up period from 1967 through 1975. Although there is at present no medical basis for linking edema, which is perhaps a marker for some unmeasured risk factor, to subsequent IHD, this finding may nonetheless have medical implications for the group of former POWs and other populations with severe dietary deficiency. It also suggests there may be a need to reexamine currently held theories on malnutrition and subsequent chronic disease.  相似文献   
43.
Abstract: Ten patients, who received cadaveric kidneys, were followed for 24 wk with serial measurements of serum erythropoietin (S-Epo), transferrin receptor (S-TfR) and iron variables. The mean pretransplant creatinine clearance was 8.2 (range 0–22) ml/min and the mean haemoglobin (Hb) level was 99±18.6 (range 66–124) g/l. Nine patients demonstrated a gradual increase in S-Epo levels, which reached a peak, and was accompanied by a parallel increase in S-TfR levels with a median lag period of 3 wk between both peaks. Hb correction followed the S-TfR peak after a second lag period (median 7 wk). Elevated S-Epo and S-TfR did not result in correction of anaemia in 1 patient due to impaired graft function. Within 4 months, S-Epo levels reached the normal range while TfR levels were higher than normal. Follow-up of iron status demonstrated the development of iron deficiency in 5 patients, which was corrected spontaneously. Improvement in erythropoiesis after renal transplantation seems to occur by means of expansion of the erythroid marrow, as detected by increasing S-TfR levels, subsequent to a S-Epo peak. This expansion precedes Hb normalization. A nonuraemic environment is probably a prerequisite for the correction of anaemia but not for the increase in S-Epo or S-TfR levels. Iron deficiency may occur after transplantation due to an increase in iron utilization.  相似文献   
44.
晚期肺癌的中医证候研究   总被引:18,自引:0,他引:18  
目的 探讨晚期肺癌的主要中医证候。方法 采用回顾性与前瞻性相结合的方法进行临床观察。结果 经 χ2 检验 ,不同中医证候的晚期肺癌组之间有显著性差异 (P <0 0 1) ,而血瘀证、气虚证、痰证、阴虚证最为多见 ;晚期非小细胞肺癌与晚期小细胞肺癌的中医证型没有显著性差异。结论 晚期肺癌的中医证候以血瘀证、气虚证、痰证、阴虚证为主 ;晚期非小细胞肺癌与小细胞肺癌的中医证候无明显差异。  相似文献   
45.
The potential for morbidity and mortality in patients who have PID with febrile and nonfebrile illness is extremely high. Familiarity with the clinical manifestations of PID and collaboration with a pediatric immunologist are prerequisites for optimal short-term care of these complex patients. Conservative management with empiric broad-spectrum antimicrobials, early and aggressive surgical debridement of abscesses, and admission at a tertiary pediatric care center are often indicated.  相似文献   
46.
47.
  • 1) The prolidase (Pd) and prolinase (Pn) activities of cultured skin fibroblasts derived from two prolidase-deficient sisters, the elder with typical clinical manifestations [symptom (+)] and the younger with only slight clinical manifestations [symptom (–)] were examined biochemically. Pd activity against several substrates other than Gly-Pro were present to some degree in both sisters. There were no detectable differences in Pd activity between the symptom (+) patient and the symptom (–) sister. Pn activity seemed to be increased in both. The lower Pn activity found against Pro-Gly as compared with those against other substrates indicates that Pro-Gly, which has been used for Pn assays in most previous reports, may not be the best substrate for this test. Pd derived from control fibroblasts was activated by Mn2+ against all substrates tested in this experiment. Cu2+, Hg2+, Cd2+ and Zn2+ remarkably inhibited enzyme activity, Co2+ slightly inhibited it, and neither Mg2+ nor Fe2+ had any remarkable effect. The Pd derived from the prolidase-deficient patients was also activated by Mn2+. This Pd seemed to be more inhibited by Co2+ than was the control. However, we found no remarkable differences between the two patients.
  • 2) We also studied Pd and Pn activities in rat skin and blood during wound healing. Pd and Pn activities adjacent to the wound increased in parallel with fibroblast proliferation. Pd activity was also detected in an extract of newborn mouse epidermis.
  相似文献   
48.
本实验用纯系CFW小鼠与Wistar大鼠建立“虚证”模型。以环核苷酸系统反应性为指标观察了肉桂挥发油的作用。通过气相色谱及气质联用等方法研究表明,本实验所提取的挥发油中桂皮醛含量约为92%。肉桂挥发油可显著降低“阳虚”——甲状腺素缺乏(甲减)模型升高了的cGMP系统反应性而使其降低了的耗O_2率升高;这是一种治疗作用。肉桂挥发油可显著升高“阴虚”——甲状腺素过多(甲亢)模型已升高了的cAMP系统反应性并使其升高了的耗O_2率进一步升高,这是一种恶化作用。这两种作用与中医对症治疗的原则是一致的。  相似文献   
49.
目的 探讨不同生长激素分泌状态下矮身材儿童血脂水平的差异,为生长激素缺乏对儿童体脂代谢的影响提供理论依据。方法 收集矮身材儿童188例,依据生长激素药物激发试验峰值分为生长激素完全缺乏(cGHD)组、生长激素部分缺乏(pGHD)组、非生长激素缺乏性(nGHD)组,研究对象均禁食禁水10 h后空腹测定总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL)和高密度脂蛋白胆固醇(HDL)4项血脂水平。结果 3组儿童HDL水平比较差异无统计学意义(P>0.05);3组儿童TC、TG、LDL、non-HDL水平比较差异均有统计学意义(P<0.05);组间两两比较,cGHD组TC、LDL、non-HDL水平较其他组明显升高(P<0.05),cGHD组TG水平较nGHD明显升高(P<0.05),与pGHD组比较差异无统计学意义(P>0.05)。pGHD、nGHD组高TC、高LDL及高non-HDL的发生率明显低于cGHD组(P<0.05),nGHD组临界高LDL的发生率明显低于cGHD组(P<0.05)。而3组间TG、HDL的异常发生率及TC、TG...  相似文献   
50.
Summary A neuromuscular disorder is reported in two brothers, aged 28 and 38 years, with glycogenosis type III. Both patients had proximal weakness, pseudohypertrophy of sternocleidomastoid. trapezius and quadriceps muscles, mild distal wasting and myopathic EMG changes. Pseudohypertrophy was more evident in the younger brother, whereas weakness was prominent in the older one. In the former, muscle biopsy revealed vacuolar myopathy and virtual absence of amylo-1,6-glucosidase enzyme. Few familial cases of debrancher deficiency neuromuscular disorder have been reported. Distal wasting has been considered a quite characteristic manifestation of the disease. It is also suggested that this particular kind of pseudohypertrophy may represent a distinctive feature of glycogenosis type III.  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