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   513篇
  免费   25篇
  国内免费   26篇
儿科学   45篇
妇产科学   8篇
基础医学   34篇
口腔科学   24篇
临床医学   53篇
内科学   129篇
皮肤病学   4篇
神经病学   6篇
特种医学   116篇
外科学   27篇
综合类   4篇
预防医学   13篇
眼科学   5篇
药学   72篇
肿瘤学   24篇
  2022年   3篇
  2021年   4篇
  2020年   3篇
  2019年   2篇
  2018年   6篇
  2017年   2篇
  2016年   4篇
  2015年   7篇
  2014年   6篇
  2013年   11篇
  2012年   7篇
  2011年   4篇
  2010年   8篇
  2009年   16篇
  2008年   9篇
  2007年   24篇
  2006年   6篇
  2005年   11篇
  2004年   4篇
  2003年   11篇
  2002年   6篇
  2001年   10篇
  2000年   5篇
  1999年   7篇
  1998年   39篇
  1997年   44篇
  1996年   51篇
  1995年   39篇
  1994年   30篇
  1993年   30篇
  1992年   9篇
  1991年   10篇
  1990年   8篇
  1989年   19篇
  1988年   18篇
  1987年   12篇
  1986年   10篇
  1985年   11篇
  1984年   9篇
  1983年   5篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1979年   4篇
  1978年   2篇
  1977年   6篇
  1976年   6篇
  1975年   8篇
  1954年   1篇
排序方式: 共有564条查询结果,搜索用时 15 毫秒
101.
OBJECTIVE: To study the relation between traumatic birth and the development of permanent facial palsy in the newborn. DESIGN: Retrospective case control study of children with 'congenital' facial palsy. SETTING: Two tertiary referral centres for patients with facial palsy. SUBJECTS: 61 children with established facial palsy. MAIN OUTCOME MEASURES: Odds ratios of recognised factors for birth injury: maternal primiparity, high birth weight, and the use of obstetric forceps at delivery. RESULTS: 13.2% of those studied had forceps assisted delivery compared to 10.2% in the normal population (odds ratio 1.34; 95% confidence intervals 0.61 to 2.97) 39.6% were born to primiparae compared to a national rate of 36.7% (1.13; 0.65 to 1.96) and only 18.9% weighed more than 3500 g at birth (0.37; 0.19 to 0.74). CONCLUSIONS: There is no association between the development of permanent 'congenital' facial palsy and recognised risk factors for birth injury. These data suggest an intrauterine rather than a traumatic aetiology.  相似文献   
102.
核磁共振法测定喃氟啶温度敏感性脂质体的相转变温度   总被引:1,自引:0,他引:1  
用核磁共振法测定了喃氟啶温度敏感性脂质体的相转变温度。此法与经典的差热分析法不同,有灵敏度高、准确性好、提供信息全面等优点。用该法测得的DPPC-脂质体和DSPC-脂质体的相转变温度分别为36℃和48℃;DPPC-DSPC-脂质体的相转变温度与DPPC和DSPC的含量有关,随DPPC含量的增加而降低,随DSPC含量的增加而增加;药物的加入及含量不影响相转变温度。同时,制得可供临床前研究用相转变温度为41℃的喃氟啶温度敏感性脂质体。  相似文献   
103.
DESIGN: A case of Nance-Horan syndrome in a male is presented, with some features of the condition in his carrier mother and her mother. It is proposed that Nance-Horan syndrome might be a contiguous gene syndrome mapping to chromosome Xp21.2–p22.3.
SETTING: The proband had congenital cataract micro-phthalmia and dental abnormalities including screwdriver shaped incisors and evidence of enamet pitting hypoplasia. The region Xp2I.2–p22.3 also contains the tooth enamet protein gene, ametogenin (AMGX).
RESULTS: Using molecular genetic techniques, we have shown that there is no evidence that the AMGX gene is deteted in this case of the Nance-Horan syndrome.  相似文献   
104.
Rifkin  MD; Marks  GJ 《Radiology》1985,157(2):499-502
Transrectal ultrasound (US; also called endosonography) was used to evaluate known or suspected rectal and perirectal masses. Thirty-one patients were examined with commercially available endosonographic probes. Those who obtained and interpreted the sonograms had no knowledge of other diagnostic studies, which included digital rectal and sigmoidoscopic examinations, conventional US, and computed tomography (CT). All but one patient underwent surgical exploration for diagnoses that included rectal cancers, perirectal abscesses, presacral endometriosis, intramural dermoid of the rectum, and intramural venous angioma. Transrectal US was able to image all masses situated within 12 cm of the anus. Malignant infiltration of perirectal fat and perirectal node involvement were detected at least as accurately with US as with CT, suggesting that this technique is a cost-effective, reliable adjunct for staging rectal cancers.  相似文献   
105.
This study was undertaken to evaluate the use of transrectal sonographically guided fine-needle aspiration biopsy and to compare sonographic with digital guidance for biopsy. In 62 patients in whom prostatic carcinoma was suspected at digital rectal examination, fine-needle aspiration biopsies were performed transperineally under sonographic guidance and transrectally under digital guidance. These patients had 89 nodules, 73 of which were sampled with both techniques. Malignant cells were obtained under digital guidance in 17 of 73 nodules (23%) and under sonographic guidance in 16 (22%). An additional seven nodules, which were not seen sonographically, were sampled under digital guidance and proved to be negative. In nine other nodules that were nonpalpable and evident only with sonography, malignant cells were obtained under sonographic guidance in three. These findings indicate that sonographic guidance for fine-needle aspiration biopsy is as good as digital guidance for palpable lesions.  相似文献   
106.
107.
Lieschke  GJ; Cebon  J; Morstyn  G 《Blood》1989,74(8):2634-2643
Bacterially synthesized recombinant human granulocyte-macrophage colony- stimulating factor (rhGM-CSF) is an agent with therapeutic potential for neutropenic states, but even at doses below the maximal tolerated dose adverse effects occur during short courses of administration. We have recognized a syndrome of hypoxia and hypotension that follows the first but not subsequent doses of rhGM-CSF. Thirteen of 42 patients receiving rhGM-CSF in phase I studies and 4 of 6 patients in a phase II study developed a reaction that occurred after the first dose of 24 of 78 cycles of rhGM-CSF therapy. The reaction was characterized by flushing (16 of 24), tachycardia (16 of 24), hypotension (14 of 24), musculoskeletal pain (13 of 24), dyspnea (12 of 24), nausea and vomiting (11 of 24), rigors (5 of 24), involuntary leg spasms (3 of 24), and syncope (3 of 24). The reaction did not occur after any of more than 600 second and subsequent consecutive rhGM-CSF doses. Oxygen saturation decreased during first-dose reactions by 8% +/- 4% as compared with 3% +/- 1% on first days without reactions (P less than .001) and 2% +/- 1% on subsequent days (P less than .001). Pulmonary dysfunction was characterized by hypoxemia (59 +/- 9 mm Hg, mean +/- SD) that was fully correctable with supplementary oxygen, decreased single-breath carbon monoxide diffusion capacity, and increased alveolar-arterial oxygen gradients (25 +/- 6 to 60 +/- 4 mm Hg, mean +/- SD), but no significant abnormalities on chest roentgenogram or lung perfusion scan. Factors predisposing to reactions were rhGM-CSF dose greater than or equal to 3 micrograms/kg (P less than .01), intravenous (IV) rather than subcutaneous (SC) administration (P less than .05), occurrence of a reaction after the first dose of a previous cycle of rhGM-CSF therapy (P less than .01), and for patients receiving 15 micrograms/kg/d by SC bolus, the presence of lung cancer (P less than .05). Administration of 15 micrograms/kg/d rhGM-CSF by 24-hour SC infusion rather than SC bolus resulted in a delayed onset of reaction from 30 +/- 8 minutes to 240 +/- 190 minutes (mean +/- SD, P less than .001), and a slower rate of initial transient decrease in neutrophil levels and a more prolonged duration of transient leukopenia. The time of onset of reactions correlated with the rate of rise of rhGM-CSF levels.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
108.
Abbadini  M; Zhu  GJ; Maggi  A; Pangrazzi  J; Donati  MB; Mussoni  L 《Blood》1987,70(6):1858-1860
Heparin or heparin-like substances have been described to induce the release of plasminogen activator (PA) activity in different animal perfusion models. In this paper we report that Dermatan Sulphate (DS) is able to induce PA activity release in the perfused rat hindquarters. Perfusion of different doses of DS (0.1 to 0.8 mg/mL) stimulates a release of PA activity that is maximum after the initial two minutes of perfusion. The amount of PA activity released rises progressively within a certain concentration range of DS (0.1 to 0.4 mg/mL) and declines thereafter (0.6 to 0.8 mg/mL). The type of PA activity increased during DS perfusion was characterized by SDS-PAGE and fibrin autography as tissue-type PA (t-PA) on the basis of its mol wt (67,000 d) and inhibition by a specific anti t-PA antiserum. This effect might be considered as potentially contributing to the antithrombotic activity of DS, at least at the local level.  相似文献   
109.
Chang  YC; Smith  KD; Moore  RD; Serjeant  GR; Dover  GJ 《Blood》1995,85(4):1111-1117
Five factors have been shown to influence the 20-fold variation of fetal hemoglobin (Hb F) levels in sickle cell anemia (SS): age, sex, the alpha-globin gene number, beta-globin haplotypes, and an X-linked locus that regulates the production of Hb F-containing erythrocytes (F cells), ie, the F-cell production (FCP) locus. To determine the relative importance of these factors, we studied 257 Jamaican SS subjects from a Cohort group identified by newborn screening and from a Sib Pair study. Linear regression analyses showed that each variable, when analyzed alone, had a significant association with Hb F levels (P < .05). Multiple regression analysis, including all variables, showed that the FCP locus is the strongest predictor, accounting for 40% of Hb F variation. beta-Globin haplotypes, alpha-globin genes, and age accounted for less than 10% of the variation. The association between the beta-globin haplotypes and Hb F levels becomes apparent if the influence of the FCP locus is removed by analyzing only individuals with the same FCP phenotype. Thus, the FCP locus is the most important factor identified to date in determining Hb F levels. The variation within each FCP phenotype is modulated by factors associated with the three common beta-globin haplotypes and other as yet unidentified factor(s).  相似文献   
110.
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