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   43039篇
  免费   3017篇
  国内免费   148篇
耳鼻咽喉   464篇
儿科学   1377篇
妇产科学   1175篇
基础医学   5946篇
口腔科学   493篇
临床医学   6275篇
内科学   8250篇
皮肤病学   716篇
神经病学   4353篇
特种医学   816篇
外国民族医学   1篇
外科学   3464篇
综合类   763篇
一般理论   42篇
预防医学   5012篇
眼科学   883篇
药学   2985篇
中国医学   79篇
肿瘤学   3110篇
  2023年   223篇
  2022年   471篇
  2021年   863篇
  2020年   478篇
  2019年   800篇
  2018年   932篇
  2017年   723篇
  2016年   804篇
  2015年   977篇
  2014年   1308篇
  2013年   1990篇
  2012年   3014篇
  2011年   3168篇
  2010年   1604篇
  2009年   1558篇
  2008年   2844篇
  2007年   3068篇
  2006年   3144篇
  2005年   3096篇
  2004年   3010篇
  2003年   2827篇
  2002年   2616篇
  2001年   376篇
  2000年   271篇
  1999年   378篇
  1998年   483篇
  1997年   419篇
  1996年   378篇
  1995年   362篇
  1994年   268篇
  1993年   298篇
  1992年   208篇
  1991年   205篇
  1990年   192篇
  1989年   182篇
  1988年   193篇
  1987年   155篇
  1986年   133篇
  1985年   153篇
  1984年   195篇
  1983年   187篇
  1982年   237篇
  1981年   178篇
  1980年   186篇
  1979年   111篇
  1978年   107篇
  1977年   112篇
  1976年   86篇
  1975年   72篇
  1974年   78篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
This article provides a commentary on "The Role of Instructional Design and Technology in the Dissemination of Empirically Supported, Manual-Based Psychothera-pies" presented by Weingardt in this issue. Weingardt uses instructional design and technology as a framework for discussing the dissemination of empirically supported therapies. In this commentary, I use Weingardt's framework and argue that treating patients is also "an instructional challenge" and use virtual reality exposure (VRE) therapy treatment as an example. Following their advantages, I conclude that (1) user-friendly design can improve acceptance and adoption; (2) dynamic, interactive design can improve learner engagement; (3) case-based presentations can provide realistic clinical context; (4) eclectic versus rule-governed implementation can be evaluated; (5) content can be reused; and (6) client self-study materials can be integrated with clinician training. I conclude that VR-assisted therapy and instructional design and technology as a framework for the dissemination of empirically supported therapies have great potential. Key words: virtual reality exposure therapy, virtual reality, manualized treatments.  相似文献   
73.
1. The rotation-mediated three-dimensional reaggregate culture system is uniquely suited for studies on developmental neurotoxicity. In this system, it is possible to reconstruct central neuronal pathways and follow their development. 2. Exposure to drugs of abuse including methamphetamine and methylenedioxyamphetamine or the appetite suppressant, fenfluramine, reduces monoamines in the cultures in a dose-dependent manner and interrupts normal monoaminergic development. 3. While the monoaminergic neurones may attain normal rates of development following drug removal, the affected neurones are not capable of overcoming the drug-induced insults and a deficiency in monoamines persists throughout development. 4. In addition, the production of immortalized monoclonal hybrid cells obtained by fusion of fetal mesencephalic neurones with a neuroblastoma has yielded cell lines expressing a dopaminergic phenotype. 5. Such cells have been useful in establishing the relationship of neurotoxicity to cell lineage and can serve as models for the study of the cellular and molecular mechanisms of neurotoxicity.  相似文献   
74.
75.
Vol. 33(4) 2003, pp 880‐888 Pages 882 (Fig. 2) and 883 (Fig. 5) The x‐axis label in Fig. 2 should have the same sampling times post‐infection as Fig. 1. The legend to Fig. 5 should be amended to read: blue nuclei, red collagen and yellow connective tissue or hepatic parenchyma.  相似文献   
76.
Technology anxiety, defined as a fear of working with medical equipment, was measured via the use of the Technology Response Questionnaire. Nurses (N=414) working on nine types of nursing units at two hospitals participated in the study. Nurses working on psychiatric units were found to be most anxious about working with medical equipment, while nurses working on surgical and adult intensive care units were least anxious. A comparison of the nurses who were highest and lowest on technology anxiety indicated that those who were most anxious about technology were less positive toward computers, felt more stressed by their work, were lower on job satisfaction, less positive toward the physicians they worked with, lower on personality scales of autonomy and adaptability, were less likely to do care planning regularly or to use nursing diagnoses, and tended to be older than less anxious nurses.  相似文献   
77.
This article reviews the normal hematologic changes in pregnancy and the kinetics of iron metabolism. The differences between iron depletion and anemia are described. The hematocrit levels of a nurse-midwifery caseload in a tertiary-care setting are described and compared with recently published population norms. Hematocrits of the sample compared favorably to the population hematocrits until 24 weeks' gestation, when the sample hematocrit mean became statistically lower and remained that way throughout pregnancy. Further analysis was done on the sample hematocrits, comparing differences in parity, age, pregnancy spacing, and AS versus AA hemoglobin. Parous women with a pregnancy interval >12 months had a higher mean hematocrit then nulliparous women. Mean hematocrits of age groups varied significantly only at the 29–32-week interval, with women younger than 18 having lower mean hematocrits than those ≥18. A trend of women with AS hemoglobin having higher hematocrits than women with AA hemoglobin was identified, reaching statistical significance at the 29–32-week interval.  相似文献   
78.
Syndromes involving peptide or nonsex steroid hormone secretion due to aberrantly located tumors are rare. We report a collected series of 16 patients with ectopic hormone production from ovarian neoplasms, including 3 patients recently encountered at our institution as well as 13 additional cases identified in the recent literature. These tumors included 2 insulin-producing ovarian carcinoids, 1 ACTH-producing pituitary adenoma within a benign ovarian cystic teratoma, 2 cortisol-producing ovarian neoplasms, 8 gastrin-producing ovarian cystadenomata or cystadenocarcinomata, and 3 thyroxine-producing ovarian strumal carcinoids. All patients presented with syndromes of hormone excess. Only 62% of all tumors were localized preoperatively. Following ovarian resection, 87% of patients remained disease-free with a median follow-up period of 1.5 years. In addition to ovariectomy, 8 additional unnecessary ablative procedures were performed in 7 patients. These included distal pancreatectomy, pancreaticoduodenectomy, adrenalectomy, total gastrectomy, selective vagotomy, and subtotal thyroidectomy. Failure to localize the ovarian neoplasm preoperatively was associated with a significantly higher risk of subsequent unnecessary ablative procedures. Because of the potential for the ovary to act as a source of aberrant hormone secretion, we recommend complete preoperative evaluation of the pelvis in female patients presenting with nonlocalizable endocrine tumors.
Resumen Los síndromes relacionados con la secreción de péptidos o de hormonas esteroideas no sexuales por tumores de ubicación aberrante ocurren infrecuentemente. En este artículo reportamos una serie de 16 pacientes con producción hormonal ectópica por neoplasmas ováricos, la cual incluye 3 pacientes vistos recientemente en nuestra institución y 13 identificados en la literatura médica de los últimos años. El grupo incluye 2 carcinoides ováricos productores de insulina, 1 adenoma pituitario productor de ACTH, 2 neoplasmas ováricos productores de cortisol, 8 cistadenomas o cistadenocarcinomas ováricos productores de gastrina, y 3 carcinoides ováricos estrumales productores de tiroxina. Todas las pacientes se presentaron con síndromes de exceso hormonal. En sólo el 62% de los tumores se pudo establecer la ubicación anatómica en la fase preoperatoria. Después de realizada la resección del ovario, 87% de las pacientes permanecieron libres de enfermedad en el período de seguimiento, que fue de 1.5 años en promedio. Además de la resección ovárica, se practicaron otros 8 procedimientos adicionales innecesarios en 7 pacientes. Estos incluyeron pancreatectomía distal, pancreatoduodenectomía, adrenalectomía, gatrectomía total, vagotomía selectiva, y tiroidectomía subtotal. La falla en la localización preoperatoria del neoplasma ovárico apareció asociada con un riesgo aumentado de ulteriores procedimientos quirúrgicos innecesarios. En vista de la potencialidad del ovario de actuar como fuente de secreción hormonal aberrante, nosotros recomendamos una completa evaluación de la pelvis en las pacientes femeninas en quienes se diagnostiquen tumores endocrinos no localizables.

Résumé Les syndromes concernant la sécrétion d'hormones peptidique ou stéroïde nonsexuelle due à des tumeurs ectopiques sont rares. Nous rapportons une série de 16 patientes avec une production d'hormone ectopique provenant de néoplasmes ovariens, comprenant 3 patientes récemment soignées dans notre établissement ainsi que 13 cas supplémentaires relevés dans la littérature récente. Ces tumeurs comprennent 2 tumeurs carcinoïdes ovariennes productrices d'insuline, 1 adénome hypophysaire producteur d'ACTH à l'intérieur d'un tératome cystique ovarien bénin, 2 néoplasmes ovariens producteurs de cortisol, 8 cystadénomes ou cystadénocarcinomes ovariens producteurs de gastrine, et 3 carcinoïdes ovariens strumaux producteurs de thyroxine. Toutes les patientes avaient des syndromes d'hyperproduction hormonale. Soixante-deux pour cent seulement des tumeurs avaient été localisées en préopératoire. Après ovariectomie, 87% des patientes étaient apparamment sans récidive avec un suivi médian d'un an et demi. Cependent, outre l'ovariectomie, 8 interventions supplémentaires non nécessaires ont été accomplis chez 7 patientes. Celles-ci comprenaient: pancréatectomie distale, duodénopancréatectomie, surrénalectomie, gastrectomie totale, vagotomie sélective, et thyroïdectomie subtotale. L'impossibilité de localiser le néoplasme ovarien en période préopératoire était associée à un risque notoirement plus grand de faire une résection inutile. Compte tenu de la possibilité pour l'ovaire de se comporter en producteur de sécrétion ectopique d'hormone, nous recommandons un examen complet préopératoire du bassin chez les femmes se présentant avec des tumeurs endocrines non localisables.


Presented at the International Association of Endocrine Surgeons in Toronto, Ontario, Canada, September, 1989.  相似文献   
79.
We examined how different methods and definitions of blood pressure affect the achievement of targets in general practice. There was a wide range in the proportion of treated patients achieving the different target levels recommended by the National Institute for Health and Clinical Excellence, British Hypertension Society and the general medical services contract. Among non-diabetic patients this ranged from; 10-37% (average office), 15-39% (standardised nurse measurement), 11-49% (last recorded) and 31-56% (ambulatory blood pressure). Defining targets without a clear definition of how blood pressure should be measured is largely meaningless and ignoring ambulatory blood pressure results in many patients being classified incorrectly as failing to achieve targets.  相似文献   
80.
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