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   2818篇
  免费   121篇
  国内免费   14篇
耳鼻咽喉   71篇
儿科学   96篇
妇产科学   87篇
基础医学   331篇
口腔科学   33篇
临床医学   221篇
内科学   673篇
皮肤病学   24篇
神经病学   206篇
特种医学   172篇
外国民族医学   1篇
外科学   489篇
综合类   7篇
一般理论   1篇
预防医学   188篇
眼科学   45篇
药学   162篇
中国医学   10篇
肿瘤学   136篇
  2023年   17篇
  2022年   41篇
  2021年   93篇
  2020年   38篇
  2019年   67篇
  2018年   69篇
  2017年   43篇
  2016年   48篇
  2015年   71篇
  2014年   81篇
  2013年   140篇
  2012年   193篇
  2011年   203篇
  2010年   118篇
  2009年   83篇
  2008年   162篇
  2007年   147篇
  2006年   146篇
  2005年   140篇
  2004年   138篇
  2003年   146篇
  2002年   134篇
  2001年   67篇
  2000年   75篇
  1999年   68篇
  1998年   22篇
  1997年   21篇
  1996年   20篇
  1995年   8篇
  1994年   19篇
  1993年   16篇
  1992年   48篇
  1991年   36篇
  1990年   28篇
  1989年   20篇
  1988年   29篇
  1987年   10篇
  1986年   16篇
  1985年   14篇
  1984年   9篇
  1983年   9篇
  1980年   7篇
  1979年   11篇
  1976年   8篇
  1973年   6篇
  1972年   6篇
  1971年   7篇
  1970年   8篇
  1969年   6篇
  1967年   8篇
排序方式: 共有2953条查询结果,搜索用时 15 毫秒
141.
It is For Teaching that the authors have done this review of the French and strange Literature about the Facial Fractures. This Study permits to join an important number of cases giving so some weight at this evaluation. However, in reason of the heterogeneity of the origins it has done seem advisable to limit this subject at the basic data.  相似文献   
142.
In a scanning microscopy study of mouse oocytes from immature, young, and aged females and of oocytes agedin vivo orin vitro, we have observed four types of zona pellucida, which we classify as types A, B, C, and D. Oocyte aging gives rise to a significant increase in predegenerative (type C) oocytes; this type of zona pellucida surface could result from a zona hardening effect and decrease the rate of fertilization of the oocytes affected.  相似文献   
143.
144.
In previous work it was shown that hepatic microsomes from rats treated with 3-methylcholanthrene and similar inducers had increased bilirubin-degrading activity. The activity was further stimulated by addition of 3,4-tetrachlorobiphenyl (TCB), a response specifically dependent on CYP1A1. Here, we compared the effect of adding PCBs of either planar or non-planar configuration on rate of bilirubin degradation, monooxygenase activity and NADPH/O(2) consumption by liver microsomes from animals treated with either phenobarbital or 3-methylcholanthrene/beta-naphthoflavone. We also examined the oxidation of uroporphyrinogen (hexahydro-uroporphyrin) (URO'gen) under these conditions. Polychlorinated biphenyl (PCBs) stimulated the rate of bilirubin and URO'gen oxidation with microsomes expressing high levels of either CYP2B or CYP1A, inhibiting at the same time their monooxygenase activities (PROD and EROD, respectively); however, non-planar di-ortho-substituted PCBs were preferentially active with phenobarbitone-induced microsomes, in contrast to those active with 3-methylcholanthrene/beta-naphthoflavone microsomes, where a planar configuration was required for activity. An antibody raised against CYP2B1 markedly inhibited the PCB-dependent bilirubin degradation and PROD activities of phenobarbital-induced microsomes with similar dose-response curves for the two effects. Increased microsomal utilizations of NADPH and O(2) were also caused by PCBs with both types of induced microsomes and here again PCBs of different configuration were preferentially active. It is concluded that PCBs of the appropriate configuration may interact with either CYP1A1 or CYP2B1, increase production of oxidative species by an uncoupling mechanism, and lead to oxidation of target molecules in the cell, among these uroporphyrinogen and bilirubin.  相似文献   
145.
146.
147.
148.
BACKGROUND: The number of proteins with mutations resulting in amyloidosis has continued to increase. Five proteins--transthyretin, fibrinogen alpha-A chain, apolipoprotein AI, lysozyme, apolipoprotein AII, cystatin C and gelsolin--can be associated with hereditary amyloidosis involving the kidney. METHODS: A French family with a history of autosomal dominant hereditary amyloidosis with early sicca syndrome and nephropathy leading to renal failure after the fifth to the seventh decade was studied. Several tissue specimens obtained from the proband and his relatives were examined. Immunohistochemistry was performed on paraffin embedded sections using the indirect immunoperoxidase technique. We searched for mutations in the five exons and flanking introns of the lysozyme gene. RESULTS: Amyloid deposits from the bowel, labial salivary gland and kidney were intensively stained by anti-lysozyme antibody. Sequence analysis of lysozyme exon 2 from the affected individuals revealed a nucleotide substitution predicting a substitution of the amino acid at position 64 in the mature protein from tryptophane, an aromatic residue to the cationic residue arginine (W64R). CONCLUSION: We report a novel mutation (W64R) of the lysozyme that is associated with hereditary amyloidosis and prominent nephropathy. Since the treatment of hereditary amyloidosis greatly varies with the nature of the amyloid protein, thorough characterization of the latter is crucial for the management of the disease.  相似文献   
149.
BACKGROUND: Although myocardial injury during cardiac surgery is associated with impaired clinical outcome, little is known about the prognostic value of cardiac troponin I (cTnI), a cardiac-specific biologic marker. The purpose of this prospective study was to evaluate the prognostic value of cTnI concentrations measured 20 h after the end of surgery in adult patients undergoing coronary artery bypass grafting or conventional valve surgery. METHODS: Baseline and perioperative characteristics of 502 consecutive patients undergoing conventional heart surgery during a 1-yr period were collected. In-hospital death (n = 28) and major clinical outcomes, e.g., low cardiac output, ventricular arrhythmia, and renal failure, were recorded. RESULTS: Multivariate analysis, using a stepwise logistic regression, showed that cTnI concentration was an independent predictor of in-hospital mortality (for cTnI concentration > 13 ng/ml, odds ratio = 6.7 [95% confidence interval, 2.3-19.3]), as were diabetes, altered preoperative cardiac function, emergent surgery, cardiopulmonary bypass duration, postoperative Pao2 level and total chest drainage volume. Further, elevated cTnI concentrations were associated with a cardiac cause of death and with major clinical outcomes. CONCLUSIONS: Our results demonstrated that cTnI concentration measured 20 h after the end of surgery is an independent predictor of in-hospital death after cardiac surgery. In addition, elevated concentrations of cTnI are associated with a cardiac cause of death and with major postoperative complications.  相似文献   
150.
Event-related fMRI was used to test the hypothesis that the visual word form area in the left fusiform gyrus holds a modality-specific and prelexical representation of visual words. Subjects were engaged in a repetition-detection task on pairs of words or pronounceable pseudo-words that could be written or spoken. The visual word form area responded only to written stimuli, not to spoken stimuli, independently of their semantic content. We propose that the occasional activation of the fusiform gyrus when listening to spoken words is due to the topdown recruitment of visual orthographic or object representations.  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