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   108045篇
  免费   7623篇
  国内免费   221篇
耳鼻咽喉   1241篇
儿科学   3050篇
妇产科学   2563篇
基础医学   16957篇
口腔科学   3139篇
临床医学   9889篇
内科学   22153篇
皮肤病学   1782篇
神经病学   10151篇
特种医学   4506篇
外国民族医学   55篇
外科学   14190篇
综合类   698篇
现状与发展   1篇
一般理论   129篇
预防医学   9416篇
眼科学   1924篇
药学   6820篇
中国医学   207篇
肿瘤学   7018篇
  2022年   793篇
  2021年   1664篇
  2020年   1113篇
  2019年   1630篇
  2018年   1943篇
  2017年   1521篇
  2016年   1785篇
  2015年   2001篇
  2014年   2567篇
  2013年   3925篇
  2012年   5494篇
  2011年   5613篇
  2010年   3627篇
  2009年   3331篇
  2008年   5011篇
  2007年   5225篇
  2006年   5183篇
  2005年   4913篇
  2004年   4717篇
  2003年   4398篇
  2002年   4168篇
  2001年   3658篇
  2000年   3671篇
  1999年   3312篇
  1998年   1421篇
  1997年   1258篇
  1996年   1157篇
  1995年   1067篇
  1994年   943篇
  1993年   957篇
  1992年   2389篇
  1991年   2248篇
  1990年   2155篇
  1989年   2086篇
  1988年   1815篇
  1987年   1717篇
  1986年   1657篇
  1985年   1528篇
  1984年   1103篇
  1983年   968篇
  1982年   647篇
  1981年   624篇
  1980年   540篇
  1979年   931篇
  1978年   543篇
  1977年   525篇
  1975年   543篇
  1974年   583篇
  1973年   523篇
  1972年   525篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Acute and chronic renal failure in liver transplantation   总被引:9,自引:0,他引:9  
We have performed a retrospective review of the incidence and etiologies of acute renal failure (ARF) in 105 adult patients receiving liver transplants. The prevalence of chronic renal failure was also determined. ARF occurred in 94.2% of these patients. Acute tubular necrosis was the leading cause of ARF and was associated with the highest mortality. Factors associated with increased mortality included: (1) peak serum creatinine greater than 3 mg/dl, (2) multiple liver transplants and (3) the need for dialysis. Pretransplant renal failure did not increase mortality. Chronic renal failure developed in 83% of patients at latest follow-up (mean: 30.5 +/- 7.9 months).  相似文献   
72.
73.
To improve the appropriateness and efficiency of diagnostic serological tests and subsequent antibiotic treatment, clinical data from 102 patients with unclassified arthritis were analysed to investigate whether the presence of positive IgG antibodies to Borrelia burgdorferi could be predicted. The clinical data were blindly ranked from 1 to 4 (1, Lyme arthritis unlikely; 4, Lyme arthritis very likely). Antibodies to B burgdorferi were positive in nine of 102 patients (9%). Six of 15 (40%) patients with rank numbers 3 and 4 were positive for antibodies to B burgdorferi, in contrast with only three of 87 (3%) patients with rank numbers 1 and 2. The likelihood ratio of positive Lyme serology for patients ranked 3 and 4 was 12.0, for patients ranked 2 to 4, 4.5, and for patients with arthritis of the knee, 3.0. These likelihood ratios were associated with a post-test probability of 55, 30, and 20% respectively. The clinical history in patients with unclassified arthritis can largely predict the presence of antibodies to B burgdorferi. The absolute value of a likelihood ratio can be a contributing factor in deciding to request tests for antibodies to B burgdorferi in patients with unclassified arthritis.  相似文献   
74.
Cultured keratinocytes were used as allografts on burn wounds in two patients. In both patients successful covering of the wounds was obtained. DNA fingerprinting of the epidermis covering the wounds 21 days later showed that the cultured keratinocytes were replaced by the patients' cells.  相似文献   
75.
Routine clinical chemical variables and parameters of the vitamin, iron and zinc status were measured in 20 female patients with anorexia nervosa (AN) and in 10 lean and 10 normal weight, healthy, female control subjects. Patients with AN had higher activities of L-gamma-glutamyl transferase (gamma-GT) and glutamate pyruvate transaminase (SGPT) and a higher concentration of prealbumin in serum and lower leucocyte and lymphocyte counts in blood. For the other routine clinical chemical parameters no significant differences between the groups were observed. AN patients had higher serum vitamin B12 and retinol levels. No significant differences were found for the status parameters of thiamin, vitamin B6, vitamin C, folate, vitamin E and vitamin D. Contradictory results were obtained for the riboflavin status: AN patients had a lower level of flavin adenine dinucleotide (FAD) in blood and a lower stimulation ratio of the glutathione reductase activity in erythrocytes (alpha-EGR). Patients with AN had higher serum ferritin concentration and lower total iron binding capacity (TIBC). However, haemoglobin (Hb), haematocrit (Ht) and iron saturation were not significantly different. No significant difference was found in the concentration of zinc in plasma. In spite of the poor intake of nutrients and energy, the results obtained did not indicate an inadequate status of vitamins, iron and zinc in patients with AN.  相似文献   
76.
77.
A new experimental model is described which can be used as an alternative to study the effects of subarachnoid hemorrhage (SAH) in rats. Vasospasm of the basilar artery is induced photochemically after transpalatal illumination of intracisternally injected rose bengal in two different rat strains. Singlet oxygen, generated in the subarachnoid space, elicits vasospasm which has been demonstrated angiographically at 90 min and 24 h after photosensitisation. Sprague Dawley rats responded better than Wistar rats. Dilution of rose bengal in water was more vasospastic than dilution of rose bengal in artificial CSF. Since the action of singlet oxygen is similar to that of free radicals, this experiment gives an argument for the hypothesis that free radicals play a leading role in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage.  相似文献   
78.
Plasma tumor necrosis factor and mortality in critically ill septic patients   总被引:23,自引:0,他引:23  
Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measurements were taken on the day that sepsis was diagnosed. Eleven patients had detectable TNF plasma levels ranging from 10 to 100 pg/ml (TNF-positive group); in 32 patients circulating TNF could not be detected (TNF-negative group). The groups did not differ significantly as to age, underlying disease, percentage positive bacteremia and bacteriologic profile, sepsis score, and extent of MOF. Eight (73%) of 11 TNF-positive patients died from sepsis during ICU stay, vs. 11 (34%) of 32 TNF-negative patients (p less than .05). This study demonstrates that sepsis is accompanied by detectable circulating TNF in 25% of the cases, and for these patients mortality is twice that for comparable TNF-negative patients.  相似文献   
79.
Pharmacokinetics of the cis-platin analog ethylenediaminemalonatoplatinum(II) (JM-410) was studied in 28 cycles of 19 patients during the phase I study of this drug. The drug was administered intravenously by short-term (10-60 min) infusion. Doses ranged from 20 to 1,200mg m-2. JM-40 was determined in plasma ultrafiltrate and urine by HPLC. Platinum (Pt) concentrations were determined in plasma, plasma ultrafiltrate, urine and red blood cells by atomic absorption spectrometry up to 5 days after administration of the drug. Ultrafilterable Pt could be determined up to 45 days after the infusion in one patient sampled over such a long period. Pharmacokinetics of JM-40 showed a linear behaviour. The final half-life of total Pt in plasma was 4.1 +/- 0.9 days. The disposition of JM-40 was similar to that of ultrafilterable Pt in respect to t1/2 alpha (10 and 13 min), t1/2 beta (44 and 57 min), volumes of distribution Vc (11 and 121) and Vss (17 and 201), systemic clearance (256 and 223 ml min-1), renal clearance (69 and 73 ml min-1) and metabolic clearance (183 and 154 ml min-1). During the first 6 h 27 +/- 9% of the administered dose was excreted as JM-40. Cumulative platinum excretion in the urine amounted to 29 +/- 13% and 60 +/- 13% over the first 6 h, 24 h and 5 days, respectively. The uptake of platinum in red blood cells was limited, comprising only 0.24 +/- 0.12% of the administered dose. Although JM-40 and carboplatin are structurally closely related, pharmocokinetics and toxicity of JM-40 were more similar to cis-platin than to carboplatin.  相似文献   
80.
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