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   10856篇
  免费   992篇
  国内免费   21篇
耳鼻咽喉   69篇
儿科学   273篇
妇产科学   247篇
基础医学   1536篇
口腔科学   427篇
临床医学   1275篇
内科学   2221篇
皮肤病学   175篇
神经病学   981篇
特种医学   270篇
外国民族医学   1篇
外科学   1418篇
综合类   161篇
一般理论   5篇
预防医学   1062篇
眼科学   114篇
药学   861篇
中国医学   12篇
肿瘤学   761篇
  2023年   81篇
  2022年   155篇
  2021年   259篇
  2020年   169篇
  2019年   220篇
  2018年   256篇
  2017年   171篇
  2016年   208篇
  2015年   217篇
  2014年   341篇
  2013年   411篇
  2012年   590篇
  2011年   632篇
  2010年   332篇
  2009年   315篇
  2008年   479篇
  2007年   535篇
  2006年   548篇
  2005年   482篇
  2004年   444篇
  2003年   439篇
  2002年   425篇
  2001年   252篇
  2000年   261篇
  1999年   284篇
  1998年   116篇
  1997年   112篇
  1996年   92篇
  1995年   76篇
  1994年   64篇
  1993年   80篇
  1992年   204篇
  1991年   181篇
  1990年   159篇
  1989年   129篇
  1988年   160篇
  1987年   137篇
  1986年   138篇
  1985年   157篇
  1984年   116篇
  1983年   92篇
  1982年   74篇
  1981年   83篇
  1979年   82篇
  1977年   65篇
  1974年   88篇
  1973年   78篇
  1971年   66篇
  1969年   65篇
  1968年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
European Surgery - Treatment of pilonidal sinus disease (PSD) requires a tailored approach. A national guideline was published in 2014. The current status of surgical PSD therapy...  相似文献   
2.
To increase our understanding of Candida pathogenicity, the identification of those strains most frequently associated with infections is of paramount importance. Polymerase chain reaction (PCR)‐based methods are extremely effective in differentiating and determining reproducibility, they require minimum starting material and are rapid and simple to perform. In this study, the genetic relatedness of Candida albicans was assessed for two geographically different patient groups (London, UK and Parma, Italy) affected by diabetes mellitus. C. albicans samples from the oral cavities of non‐diabetic healthy subjects were also examined by PCR fingerprinting to evaluate the possible genetic differences among endogenous strains in individuals with and without diabetes mellitus. PCR fingerprinting, with subsequent phylogenetic analysis of C. albicans isolates from the diabetic patients from London and Italy and from the non‐diabetic subjects, revealed that there were significant differences (P < 0.0001) between C. albicans isolates indicative of the distinct ecological niches that occur in the oral cavities of these patient cohorts. The most diverse group comprised the isolates from the diabetic patients in the UK, possibly reflecting the antifungal treatment that these patients had received. Further studies that include isolates from patient cohorts with systemic diseases other than diabetes mellitus, and from more diverse geographic localities are required to explain the relatedness of C. albicans isolates in the mouth.  相似文献   
3.
4.
The ability of a number of heterocyclic metal chelators to deliver zinc into red cells, to release the liganded zinc to haemoglobin and thereby cause a left shift in the oxygen dissociation curve of intact red cells has been investigated. Incubation of neutrally charged zinc-pyrone and zinc-pyridin-2-one complexes with red cells led to the rapid accumulation of zinc within cells, whereas unliganded zinc in the form of zinc acetate, zinc chloride or zinc sulphate accumulated only slowly. The rate at which zinc was delivered to red cells by pyrone and pyridin-2-one ligands increased with increasing lipid solubility of the ligands. The uptake of zinc into both normal adult and sickle red cells was associated with a dose-dependent increase in the oxygen affinity of haemoglobin. The degree of left shift in the oxygen dissociation curve following the incubation of red cells with zinc-pyrone and -pyridin-2-one complexes suggests that these complexes may find application as agents to increase the oxygen affinity of haemoglobin in sickle cell disease and thereby decrease the probability of intravascular sickling at low tissue oxygen tensions. Ethylmaltol appears to be a particularly useful agent due to its known low toxicity.  相似文献   
5.
Juvenile Parkinsonism: clinical and metabolic characteristics.   总被引:1,自引:1,他引:0       下载免费PDF全文
Twenty one patients with idiopathic Parkinsonism beginning before the age of 40 years were investigated. The mean duration of the disease was 19 years. There was a good and sustained response to levodopa. Only four patients reached stages IV and V (Hoehn and Yahr). Intolerance to levodopa was observed in the more advanced stages of the disease. In the series the familial incidence of Parkinsonism (2 cases) and essential tremor (3 cases) was very low. Thyroid disorder, diabetes mellitus or macrocytic anaemia was not found in any of the cases.  相似文献   
6.
This study was conducted to determine if lower steroid secretion by the small white follicles in incubating turkey hens contributes to lower circulating steroid concentrations during this time. Turkey hens were grouped as either laying or incubating. Serum samples and the ovarian small white follicles (SWF; 2-7 mm diameter) were collected from each hen. The SWF were pooled for each group and their cells were dispersed by trypsin digestion. Serum-luteinizing hormone (LH), progesterone (P), testosterone (T), and estradiol (E) concentrations were lower and serum prolactin concentration was higher during incubation than during egg laying. SWF cells from incubating hens secreted more P and T and less E in response to ovine luteinizing hormone (oLH) than did similar cell suspensions from laying hens. The incubating hens' SWF cells' capacity to secrete E but not their capacity to secrete P or T in vitro is consistent with the observed circulating levels. It is hypothesized that lower levels of circulating LH and/or higher levels of prolactin found in incubating hens may have a depressing effect on aromatase activity and/or an up-regulating effect on LH-induced P and T secretion by the SWF cells.  相似文献   
7.
8.
Acute myelogenous leukemia (AMU is a hematologic disorder that is characterized by an abnormal proliferation of immature myeloid cells. Granulocytic sarcomas are clusters of leukemic myeloid cells that may develop as a result of AML. Oral manifestations of AML are common and often involve enlargements of the gingiva and/or mucosal tissue from direct leukemia cell infiltration. We describe the case history of a 50-year-old man who had an ulcera-tive lesion of the oral mucosa that was determined to be a granulocytic sarcoma of AML-M0 subtype. The combination of both the subtype and clinical presentation of the leukemia makes this presentation unusual, and to the best of our knowledge, of a type that has not been previously reported in the literature.  相似文献   
9.
10.
To identify and compare the methods of evaluation for suspected traumatic aortic rupture, 1,031 trauma charts from 1983-1989 were reviewed. Fifty-nine patients were evaluated for possible aortic injury. Patients who died before completion of the CT or aortogram were excluded. Widening of the mediastinum on chest x ray was the most frequent indication for follow-up studies. Twenty-five had a CT of the aortic arch alone. No study showed disruption. There were no false negative studies. Thirty patients had only aortography. Twenty-four were read as normal (one false negative). Six were read as positive (one false positive). In four, both studies were performed (CT/aortography--TP/TP, TN/TN, TP/FN, FP/FP). (FP = False Positive, TP = True Positive, FN = False Negative, TN = True Negative.) Six received surgical repair of the aortic injury (one death). In this experience, CT was used successfully as a screening tool for aortic disruption. It was highly sensitive in recognizing aortic injuries when present (100% vs. 75% for aortography) and in most cases did not require aortographic verification. False positive rates were comparable (CT = 3.8%, aortography = 7.7%). Specificity was also comparable (CT = 96%, aortography = 92%). Overall, four aortograms were inaccurate while only one CT was inaccurate. We recommend the use of CT for the evaluation of widened mediastinum in the stable patient.  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