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   2301篇
  免费   183篇
  国内免费   57篇
耳鼻咽喉   9篇
儿科学   89篇
妇产科学   34篇
基础医学   321篇
口腔科学   34篇
临床医学   264篇
内科学   490篇
皮肤病学   63篇
神经病学   72篇
特种医学   386篇
外科学   243篇
综合类   51篇
一般理论   3篇
预防医学   139篇
眼科学   26篇
药学   118篇
中国医学   2篇
肿瘤学   197篇
  2021年   28篇
  2020年   31篇
  2019年   38篇
  2018年   48篇
  2017年   17篇
  2016年   25篇
  2015年   35篇
  2014年   30篇
  2013年   69篇
  2012年   59篇
  2011年   49篇
  2010年   54篇
  2009年   83篇
  2008年   70篇
  2007年   111篇
  2006年   58篇
  2005年   90篇
  2004年   59篇
  2003年   70篇
  2002年   62篇
  2001年   62篇
  2000年   56篇
  1999年   60篇
  1998年   89篇
  1997年   88篇
  1996年   117篇
  1995年   76篇
  1994年   69篇
  1993年   67篇
  1992年   32篇
  1991年   44篇
  1990年   38篇
  1989年   70篇
  1988年   57篇
  1987年   49篇
  1986年   64篇
  1985年   61篇
  1984年   27篇
  1983年   34篇
  1982年   23篇
  1981年   21篇
  1980年   31篇
  1979年   26篇
  1978年   20篇
  1977年   17篇
  1976年   23篇
  1975年   17篇
  1973年   17篇
  1972年   14篇
  1970年   14篇
排序方式: 共有2541条查询结果,搜索用时 15 毫秒
31.
Summary The artery of the sino-atrial node was studied in 100 normal human hearts after injection of each coronary artery with coloured gelatine containing a radiopaque substance. The hearts belonged to 69 males and 31 females, being 64 Caucasians and 36 non-Caucasians (Negroes and Mulattoes) whose age ranged from 7 to 80 years. Since the individuals had committed suicide or were victims of accidents, their hearts, after pathologists' evaluation, were considered normal. The sinoatrial node of the normal human heart is supplied by the right coronary artery more frequently (58%±4.9% of the cases) than by the left (42%±4.9). The right anterior medial atrial artery, originating from the right coronary at the level of the medial third of the right anterior quadrant of the atrial dome, is most frequently (50%±5) responsible for the blood supply of the sinoatrial node. Among the branches of the left coronary artery, the left anterior medial atrial artery, originating at the level of the medial third of the left. anterior quadrant of the atrial cupola, was the most frequent blood supplier (25%±4.3) of the sinoatrial node. The origin of the artery of the sinoatrial node from the proximal portion or trunk of the left coronary artery was less frequent (12%±3.2) than the origin from the circumflex artery (30%±4.5). Neither sex nor race influenced the variations of the origin of the sino-atrial node.
Variations d'origine de l'artère du noeud sinu-atrial du coeur humain normal
Résumé L'a. du noeud sinu-atrial a été étudiée sur 100 coeurs humains normaux après injection de chaque a. coronaire à la gélatine colorée additionnée d'une substance radio-opaque. Les coeurs provenaient de 69 hommes et 31 femmes, 64 caucasiens et 36 non caucasiens (nègres et mulâtres) âgés de 7 à 80 ans. Ces sujets étant décédés par suicide ou des suites d'accidents, leurs coeurs ont été considérés comme normaux après examen anatomo-pathologique. Le noeud sinu-atrial du coeur humain est vascularisé par l'a. coronaire droite plus fréquemment (58 %±4,9) que par l'a. coronaire gauche (42 %±4). L'a. atriale antéro-médiale droite, issue de l'a. coronaire droite au niveau du tiers médial du quadrant antérieur droit du dôme atrial est l'artère la plus fréquemment en cause (50 %±5) dans la vascularisation du noeud sinuatrial. Parmi les branches de l'a. coronaire gauche, l'a. atriale antéro-médiale gauche, née au niveau du tiers médial du quadrant antérieur gauche du dôme atrial, était la branche la plus fréquemment en cause (25 %±4,3) dans la vascularisation du noeud sinu-atrial. La naissance de l'a. du noeud sinu-atrial à partir de la partie proximale ou du tronc de l'a. coronaire gauche était moins fréquente (12 %±3,2) que son origine à partir du rameau circonflexe (30 %±4,5). Les variations d'origine de l'a. du noeud sinu-atrial n'apparaissaient pas influencées par le sexe ou la race.
  相似文献   
32.
Five hundred allergy clinic patients were prick skin tested with papain, 1 mg/mL, in addition to usual local aeroallergens. Five of 475 subjects with seasonal allergic disease had positive skin tests to both papain and local pollens. None of the 25 individuals with negative skin test to pollens had skin reactivity to papain. The five subjects with positive skin tests to papain underwent double-blind placebo-papain challenges. All papain challenges were positive. Placebo challenges were negative. Papain-induced symptoms included palatal itching, watering itchy eyes, sneezing, rhinorrhea, abdominal cramps, diarrhea, and diaphoresis. Circulating papain-specific IgE was detected in all the papain-sensitive individuals, but not in control subjects. Confirmed papain sensitivity occurred in 1.05% of allergic subjects. In the papain-sensitive patients, cross-reacting antibodies with chymopapain were found. The small number of non-allergic subjects did not show any papain or chymopapain sensitivity in vitro.  相似文献   
33.
A double-blind modification of the intraesophageal acid perfusion challenge (Bernstein procedure) was performed in asthmatic subjects with and without gastroesophageal reflux, nonasthmatic subjects with reflux, and normal subjects. Conventional spirometric functions and total respiratory resistance (Rrs) were measured prior to and after the infusion. There were no changes in pulmonary functions except in the asthmatic subjects who had had a positive add challenge. The greatest changes occurred in Rrs, which increased significantly with reflux symptoms (p < 0.01) and decreased toward baseline (p < 0.05) when these symptoms were relieved with antacids. The response was even greater in asthmatic subjects who associated reflux symptoms with attacks of asthma. These results support previous findings that acid reflux symptoms could cause a bronchoconstrictive response in certain asthmatic patients.  相似文献   
34.
Increased antiphospholipid antibody prevalence has been demonstrated by a number of recent studies in in-vitro fertilization (IVF) patients but the potential effects of antiphospholipid antibodies on the different components of the reproductive process and the consideration of whether to test IVF patients for antiphospholipid antibodies are controversial. The present study was undertaken to investigate the possible association between the presence of circulating antiphospholipid antibodies (namely the lupus anticoagulant and anticardiolipin antibodies), among a series of 21 consecutive IVF patients having a clinical spontaneous abortion after their first embryo transfer. As a control group (n=42), the nearest IVF cycle resulting in an ongoing pregnancy before and after each miscarried IVF cycle (i.e. the closest cycles in temporal relationship to the index cycle) was used. One patient (4.8%) in the study group and two women (4.8%) among controls were seropositive for antiphospholipid antibodies. These low and similar seropositivity rates found in the two groups studied lead us to conclude that antiphospholipid antibodies testing in IVF patients should be considered only in those women having repeated failures of implantation/clinical abortion after embryo transfer but not in an infertile general population reaching an IVF programme.   相似文献   
35.
BACKGROUND: Randomised controlled trials have shown the efficacy of several treatment modalities for lower urinary tract symptoms (LUTS) in selected populations. The effectiveness in daily practice has hardly been investigated, especially in primary care and is dependent on choices between all possible treatment options and best investigated in a comprehensive study, including all treatment modalities (watchful waiting, alpha-blockers, 5-alpha-reductase inhibitors, and surgery). AIM: Assessment of the effectiveness of a comprehensive treatment protocol for LUTS in primary care. DESIGN OF STUDY: Randomised controlled trial. SETTING: Fourteen general practices in the Netherlands. METHOD: Intervention: treatment protocol based on a formalised expert opinion. Control condition: usual care. Study population: 208 subjects with moderate to severe LUTS (IPSS > or =8, median = 13). OUTCOME MEASURES: symptom severity (IPSS [International Prostate Symptom Score]), bother score (Dan-PSS [Danish Prostate Symptom Score]), and maximum urinary flow (Q(max)); incidence of acute urinary retention and urinary tract infections. RESULTS: In the intervention group markedly more subjects used an alpha-blocker at end of follow-up than in the usual care group (24% versus 6%). No significant differences were found between intervention and control group in IPSS, Q(max) or Dan-PSS. CONCLUSION: alpha-blockers and watchful waiting are the most frequent treatment modalities for LUTS in primary care. Our study showed no evidence that a protocol using well-defined indications for all possible treatment modalities based on a formalised expert opinion procedure has added value. Based on our results, we cannot recommend a broadening of the indication for alpha-blockers, which, however, seems to be the current trend.  相似文献   
36.
Donor insemination (DI) using cryopreserved semen commenced at The Royal Women's Hospital in 1976. Over the next 15 years we performed 5953 treatment cycles to achieve 816 pregnancies (13.7% per cycle) and 706 live births. In-vitro fertilization (IVF) using donor spermatozoa commenced in 1986. Over the next 5 years we performed 303 treatment cycles for 185 couples. Including subsequent transfer of cryopreserved embryos, a total of 33% of couples achieved a successful pregnancy by IVF. Statistical analysis indicated that, for DI pregnancies, the most important semen variable was the percentage post-thaw motility, whilst for normal fertilization in IVF it was the pre-freeze motility. These results may be explained by the compensatory effects of post-thaw processing of spermatozoa for IVF, but not for DI in our clinic.   相似文献   
37.
38.
39.
40.
Summary In view of the increasing popularity of the direct lateral approach to the hip joint for hemi- or total hip arthroplasty, the location of the superior gluteal nerve (SGN) was studied. This nerve is in danger when using a transgluteal incision. In 20 embalmed specimens the relation of the SGN to the tip of the greater trochanter (TT) was studied as well as the relation to the iliac crest. For this purpose macroscopy, microscopy and CT were used. In 13 hips a so-called most inferior branch was found at an average of 1 cm distal to the inferior branch, the main trunk of the nerve. There was substantial variation in the course of both the inferior and the most inferior branch of the SGN. In order to prevent nerve damage, proximal extension of the transgluteal incision should be limited to 3 cm cranial to TT. Furthermore the incision has to be confined to the distal one third of the distance TT-iliac crest. In tall people extra care should be taken.
Anatomie chirurgicale du nerf glutéal supérieur et bases anatomo-radiologiques de l'abord latéral direct de la hanche
Résumé Les recours de plus en plus fréquent à la voie latérale directe de la hanche pour les prothèses totales ou cervico céphaliques nous a conduit à étudier la localisation du nerf glutéal supérieur (SGN) qui est exposé lors de l'incision transglutéale. Les rapports du SGN avec le sommet du grand trochanter (TT) et avec la crête iliaque ont été étudiés sur 20 cadavres embaumés. Nous avons eu recours à l'étude macroscopique, microscopique ainsi qu'au scanner. Dans 13 cas nous avons mis en évidence une branche très inférieure, donc plus distale, située 1 cm en moyenne en dessous de la branche inférieure habituelle de bifurcation du tronc principal. Il existait des variations importantes dans les trajets de ces deux branches inférieures. Afin de prévenir une lésion chirurgicale du nerf, l'incision transglutéale ne doit pas aller au delà de 3 cm du sommet du grand trochanter, de plus l'incision doit être confinée en dessous du tiers distal de la ligne joignant le grand trochanter à la crête iliaque.
  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