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   27181篇
  免费   2032篇
  国内免费   155篇
耳鼻咽喉   236篇
儿科学   935篇
妇产科学   747篇
基础医学   3567篇
口腔科学   438篇
临床医学   2880篇
内科学   5980篇
皮肤病学   584篇
神经病学   2930篇
特种医学   639篇
外科学   2713篇
综合类   186篇
一般理论   37篇
预防医学   3187篇
眼科学   351篇
药学   1774篇
  1篇
中国医学   41篇
肿瘤学   2142篇
  2023年   365篇
  2022年   597篇
  2021年   1265篇
  2020年   797篇
  2019年   1049篇
  2018年   1144篇
  2017年   865篇
  2016年   943篇
  2015年   999篇
  2014年   1313篇
  2013年   1569篇
  2012年   2294篇
  2011年   2348篇
  2010年   1215篇
  2009年   1030篇
  2008年   1555篇
  2007年   1527篇
  2006年   1385篇
  2005年   1248篇
  2004年   1078篇
  2003年   936篇
  2002年   833篇
  2001年   261篇
  2000年   230篇
  1999年   211篇
  1998年   159篇
  1997年   142篇
  1996年   110篇
  1995年   106篇
  1994年   77篇
  1993年   81篇
  1992年   133篇
  1991年   100篇
  1990年   90篇
  1989年   111篇
  1988年   98篇
  1987年   104篇
  1986年   87篇
  1985年   72篇
  1984年   82篇
  1983年   55篇
  1982年   62篇
  1981年   59篇
  1980年   37篇
  1979年   38篇
  1978年   35篇
  1977年   36篇
  1976年   37篇
  1975年   39篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
Zusammenfassung In der Zeit vom 01. Juli 1990 bis zum 30. Juni 1994 wurden 65 113 Untersuchungen au?erhalb der Regeldienstzeit durchgeführt. Die vorliegende Analyse schlüsselt die Leistungen auf nach Alter und Geschlecht im Vergleich zum Gesamtkollektiv dieser Vierjahresperiode, nach dem Zeitpunkt der Untersuchung, nach den untersuchten Organen und nach der eingesetzten Technik. Ca. 1/3 der Leistungen fallen in den Zeitraum zwischen 16.00 und 20.00 Uhr und k?nnten durch einen versetzten Tagdienst aufgefangen werden. Ein weiteres Drittel entf?llt auf den Zeitraum zwischen 20.00 und 8.00 Uhr am Folgetag. Der Rest entf?llt auf Feiertage und Wochenenden. Die h?ufigste Anforderung betrifft Thoraxaufnahmen auf den Intensivstationen. Etwa die H?lfte dieser Untersuchungen werden au?erhalb der Dienstzeit angefertigt; 17,2 % der Untersuchungen im Nacht- und Bereitschaftsdienst betreffen Computer- und Magnetresonanztomographie. Das am 01. 01. 93 in Kraft getretene Gesundheitsstrukturgesetz führte zu keinen nennenswerten Verschiebungen hinsichtlich Art, Umfang und H?ufigkeit der Untersuchungen im Nacht- und Bereitschaftsdienst. Eingegangen am 17. Juni 1996 Nach überarbeitung angenommen am 24. Juli 1996  相似文献   
92.
Seven days or more of inadequate oral intake (IOI) inevitably results in a deterioration in nutritional status. Despite this well-known fact, little information is available as to the frequency with which such periods of IOI occur in clinical practice. This study results from an audit of IOI in a gastroenterological unit over a 6-month period. The results demonstrate that 17% of patients sustained significant periods of IOI of 7 days or longer. This has important implications with regard to the provision of adjuvant nutritional support.  相似文献   
93.
Over a period of 2 years patients with exogenic intoxications take 16% in the total number of patients of the department for internal intensive care. The cases in question were 43.3% males and 56.7% females. The average age of the patients with 31 years was low. The mortality was 2.4%. In the first place of the exogenic intoxications were intoxications with the groups of medicaments sedatives, hypnotics, tranquilizers, analgetics and antipyretics followed by intoxications with neuroleptics, beta-receptor blockers, antidepressives, antiepileptics and glycosides. The rate of complications was greatest in the mixed intoxications.  相似文献   
94.
Two enzyme immunoassays (EIAs) detecting Chlamydia trachomatis from endocervical swabs, Syva MicroTrak (MT) and Abbott Chlamydiazyme (CZ), were compared with a tissue culture (TC) standard. Initially, 8% (100 of 1250) of specimens were TC positive, yielding sensitivities of 94% (94 of 100) for MT and 79% (79 of 100) for CZ with identical 98% specificities (1129 of 1150 for MT and 1130 of 1150 for CZ). Discrepant specimens were retested by both EIAs and assayed for elementary bodies (EBs) by a fluorescent antibody test. After discrepancy analysis, 9.5% (118) of 1240 patients were either TC or EB positive, yielding sensitivities of 94.1% for MT (111 of 118) and 79.7% for CZ (94 of 118) with identical specificities of 100% (1122 of 1122). These results indicate that the MT is significantly more sensitive (p less than 0.05, McNemar test) than CZ in detecting C. trachomatis from endocervical swabs.  相似文献   
95.
This study examined whether response to behavior modification with and without methylphenidate differed for children with attention-deficit/hyperactivity disorder (ADHD) and conduct problems (CP) depending on the presence of callous/unemotional (CU) traits. Participants were 37 children ages 7 to 12, including 19 with ADHD/CP-only and 18 with ADHD/CP-CU, referred to a university-based summer treatment program. Results showed that ADHD/CP-CU children had worse behavior in the behavior-therapy-only (BT-only) condition, especially on measures of CP, noncompliance, and rule violations, but these differences largely disappeared when medication was added to BT. Children with ADHD/CP-CU were also less likely to be normalized by treatment than were children with ADHD/CP-only. These findings, though tentative, suggest that children with ADHD/CP-CU may not show a sufficient positive response to BT alone and that the combination of medication and BT may be especially important for them.  相似文献   
96.
97.
An enzymatic assay for creatine, depending on the creatine kinase reaction, has been modified for the determination of creatine in packed erythrocytes, using a centrifugal analyzer (COBAS BIO). The method is precise, sensitive and shows excellent accuracy in recovery experiments when compared to the diacetyl-alpha-naphthol method. The enzymatic red cell creatine correlates with the erythrocyte survival time determined with the radioactive chromium method. It can be used as a rapidly available parameter for the quantification of hemolytic processes.  相似文献   
98.
99.
Granulocyte-macrophage colony stimulating factor (GM-CSF) modulates various functions of monocytes/ macrophages including antigen-presenting capacity. Recently it was found that astrocytes produce GM-CSF in the central nervous system (CNS) and that GM-CSF can induce proliferation and morphological changes of microglia. Here we show that GM-CSF can down regulate the interferon-γ-mediated induction of major histocompatibility complex (MHC) class II antigens in microglia, but not in astrocytes. GM-CSF pretreatment completely prevents myelin basic protein-specific T cell proliferation induced by microglia but not astrocytes. GM-CSF did not affect the cell surface expression on microglia of either MHC class I or cell adhesion molecules. The inhibition of microglial MHC class II expression and antigen-presenting function is specific for GM-CSF, as treatment with a different CSF (interleukin-3) did not modulate microglial phenotype or functional capacity. These data suggest that GM-CSF might be involved in the regulation of immune responses within the central nervous system.  相似文献   
100.
Summary In this study any changes in action potential duration or Q-T interval due to acute doses of ketanserin were monitored. The effect of a bolus dose (10 or 20 mg) followed by an infusion (10 or 20 mg over 20 minutes) of ketanserin on the Q-T interval and action potential duration was studied in six patients undergoing routine cardiac catheterization. Action potential duration was measured with a silver-silver chloride electrode catheter while heart rate was kept constant by atrial pacing and reflex effects avoided by -adrenergic blockade. There were some prolongations of the action potential duration but they were not in excess of 40 msec and did not reach statistical significance (control 263±46.0 msec; bolus 269±52.1 msec; infusion 262±53.6 msec; nor were there any significant changes in Q-T interval. Thus acute intravenous doses of ketanserin, in the absence of hypokalaemia or other Q-T interval-prolonging drugs, have no consistent effect on Q-T interval or action potential duration; prolongation of the action potential, when it occurs, is small.  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