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   22861篇
  免费   1551篇
  国内免费   112篇
耳鼻咽喉   376篇
儿科学   502篇
妇产科学   402篇
基础医学   3058篇
口腔科学   2044篇
临床医学   1757篇
内科学   5111篇
皮肤病学   566篇
神经病学   1798篇
特种医学   710篇
外国民族医学   1篇
外科学   2796篇
综合类   93篇
一般理论   9篇
预防医学   1966篇
眼科学   401篇
药学   1643篇
中国医学   130篇
肿瘤学   1161篇
  2023年   198篇
  2022年   550篇
  2021年   908篇
  2020年   583篇
  2019年   781篇
  2018年   886篇
  2017年   640篇
  2016年   730篇
  2015年   811篇
  2014年   1022篇
  2013年   1277篇
  2012年   1813篇
  2011年   1885篇
  2010年   1058篇
  2009年   859篇
  2008年   1330篇
  2007年   1401篇
  2006年   1188篇
  2005年   1092篇
  2004年   918篇
  2003年   708篇
  2002年   668篇
  2001年   384篇
  2000年   364篇
  1999年   292篇
  1998年   128篇
  1997年   105篇
  1996年   85篇
  1995年   91篇
  1994年   80篇
  1993年   60篇
  1992年   139篇
  1991年   143篇
  1990年   132篇
  1989年   108篇
  1988年   100篇
  1987年   98篇
  1986年   89篇
  1985年   88篇
  1984年   79篇
  1983年   65篇
  1982年   48篇
  1981年   31篇
  1980年   33篇
  1979年   61篇
  1978年   42篇
  1977年   30篇
  1970年   29篇
  1967年   28篇
  1966年   28篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Investigators have tried to identify a level of seric specific immunoglobulin E (IgE) that had a sufficient predictive value to diagnose a food allergy without having will resort to the food challenge. To search in literature, all the studies that have estimated the possibility to identify a level of seric specific cow milk IgE with a positive predictive value (PPV) of 95% for the first diagnosis of cow's milk allergy (CMA) in pediatric age. We have identified six studies, nearly all studies suffer from relevant methodological bias. Proposed cut-off are all different. The studied pediatric populations were highly selected. Also neglecting the methodological bias of the studies and the great difference of value between the proposed cut-off, it always remains to consider that the pre-test probability of having a CMA between the children enrolled in the six studies included in this review is particularly high. The likelihood ratio helps to transfer the results of a study on a diagnostic test just to our population, and it is more realistic rather than to entrust itself to the PPV or the negative predictive value, that are much influenced from the prevalence of the disease in the studied population.  相似文献   
62.
63.
The periodontal condition of patients with insulin-dependent diabetes mellitus was evaluated in terms of plaque, gingival indices, pocket depth, and alveolar bone loss. Thirty male and female diabetic patients aged 5 to 18 years were compared with 30 non-diabetic subjects and correlated with sex and age. Statistical analyses of the data showed that the mean plaque index was significantly higher (P less than 0.01) among the diabetic patients (1.23) than among the control subjects (0.81). The plaque index was significantly higher (P less than 0.01) among diabetic females (1.34) than among diabetic males (1.10), whereas no sex differences were observed in the control group. The arithmetic means obtained for gingival index were statistically higher (P less than 0.01) for the diabetics (0.58) when compared with the controls (0.15), but no significant differences were obtained when the values were correlated with sex and age. Pocket depth did not differ statistically between groups. When pocket depth was correlated with sex, a statistically significant difference (P less than 0.05) was observed only for the palatal region, with a depth of 2.1 mm in female patients and 1.92 mm in male patients. When pocket depth was correlated with age, a positive correlation (P less than 0.01) was detected in the diabetic group for all regions investigated, whereas the correlation was not significant in the control group. Mean alveolar bone loss was higher in the anterior upper (1.94 mm) and anterior lower (1.87 mm) regions of the diabetic group when compared to the controls (1.52 and 1.37 mm respectively), the difference being significant at the 5% level of probability.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
64.
The evolution of surgery for obstructed colon started at the turn of the century, and was guided by 3 main therapeutic principles: decompression (colostomy or internal derivation); tumour resection; reestablishment of function. These objectives were attained with various solutions and can be summarized in 3 approaches: the 3 stage operation, the 2 stage operation with initial resection of the tumour and finally the colonic resection with immediate reestablishment of function. The analysis and comparison of our personnel experience (n = 655), and the review of the literature lead us to the following conclusions: 1) the 3 stage operation, with a global mortality in our series of 27.6%, has been abandoned and is rarely dependable today; 2) the primary resection of the tumour, which should be an important objective, reduces mortality (18.8% in our experience); 3) of the methods including the primary resection of the tumour, those with immediate reconstruction of the digestive integrity and sub-total colectomy should be favoured, using the ileon as the proximal limb of the anastomosis (8.5% mortality in our series).  相似文献   
65.
Peripheral blood neutrophils (PMN) from patients with paracoccidioidomycosis killed and digested Paracoccidioides brasiliensis much less than did PMN from normal individuals or from patients with other diseases. However, deficiency in killing ability was less specific than digestive deficiency and correlated poorly with it. We conclude that the capacities of PMN to digest and kill P. brasiliensis are not intimately related phenomena, and that in paracoccidioidomycosis the key deficiency of neutrophil function is that of digestion of P. brasiliensis.  相似文献   
66.
67.
68.
Thirty-eight nontoxigenic strains ofCorynebacterium diphtheriae isolated between 1987 and 1992 from clinical specimens of French patients were typed by biotyping, antibiograms, bacteriophage typing, ribotyping, and restriction analysis by pulsed-field gel electrophoresis (PFGE). Excellent correlation occurred between the genotypes defined by PFGESfil profiles or by ribotypeBstEll profiles. Genotyping revealed seven genotype patterns among the 26 biotype mitis isolates, five among the nine biotype gravis isolates, and three among the three biotype belfanti isolates. Phage typing was nonreactive for nine of the 38 isolates. A combination of all the typing methods led to the identification of 19 different types ofCorynebacterium diphtheriae.  相似文献   
69.
Slightly elevated values of homocysteine are commonly associated with thromboembolic diseases, while high values can be found in patients with congenital metabolic defects or nutritional problems. The clinical use of homocysteine as an independent marker of cardiovascular disease was limited in the past by technical problems with its measurement, the instrumentation (HPLC, radioenzymatic assays, gas chromatography-mass spectrometry, etc.) and the necessary skills required. Commercially available immunoassays now permit a simpler and more rapid measurement of homocysteine, that is more suitable for routine clinical laboratories; in this paper we analyze the results obtained by using three fully automated methods for homocysteine determination (Abbott IMx immunoassay, Abbott AxSYM immunoassay and Immulite 2000 homocysteine immunoassay) and their correlation with the widely used HPLC method. The results clearly indicate that all three automated immunochemical methods correlate well with the HPLC method (slope 0.97-1.03; intercept 0.95-1.91 with a recovery above 95% for all three methods).  相似文献   
70.
The purpose of this study was to assess the concentration and binding pattern of zinc, iron, folate and vitamin B12 in milk of Brazilian women of low socioeconomic status giving birth at term or preterm, during early lactation. Protein, fat, total solids and ash concentrations were also determined. Protein and zinc concentrations decreased significantly as lactation proceeded whereas milk fat and folate increased with the lactation period. Total solids, ash, iron and vitamin B12 remained unchanged. Zinc was present mainly in the whey fraction while less than half of the total iron was present in this fraction, with no significant change due to stage of lactation. Unsaturated folate and vitamin B12 binding capacities and percentage of saturation of the folate binding protein increased with the stage of lactation. The vitamin B12 binding protein was highly unsaturated in all samples. There was no significant difference between term and preterm samples in the parameters investigated. Correlation analysis between milk components indicated significant relationships between total solids and fat, total zinc and whey zinc, folate and total folate binding capacity, unsaturated and total folate binding capacity, and unsaturated and total B12 binding capacity. In general, the nutrient concentrations found in this study are in good agreement with published data on milk composition of women from developed countries, with the possible exceptions of folate, which was lower, and iron, which was higher. The correlation of folate concentration with its binding protein found in this work supports the hypothesis of a regulatory role for folate levels in milk exerted by the folate binding protein in the mammary gland.  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