全文获取类型
收费全文 | 16142篇 |
免费 | 1104篇 |
国内免费 | 78篇 |
专业分类
耳鼻咽喉 | 144篇 |
儿科学 | 338篇 |
妇产科学 | 334篇 |
基础医学 | 1980篇 |
口腔科学 | 353篇 |
临床医学 | 1605篇 |
内科学 | 3171篇 |
皮肤病学 | 196篇 |
神经病学 | 1582篇 |
特种医学 | 637篇 |
外科学 | 2508篇 |
综合类 | 189篇 |
现状与发展 | 1篇 |
一般理论 | 29篇 |
预防医学 | 1370篇 |
眼科学 | 520篇 |
药学 | 1256篇 |
中国医学 | 29篇 |
肿瘤学 | 1082篇 |
出版年
2024年 | 18篇 |
2023年 | 147篇 |
2022年 | 292篇 |
2021年 | 630篇 |
2020年 | 308篇 |
2019年 | 466篇 |
2018年 | 549篇 |
2017年 | 403篇 |
2016年 | 413篇 |
2015年 | 508篇 |
2014年 | 684篇 |
2013年 | 820篇 |
2012年 | 1330篇 |
2011年 | 1290篇 |
2010年 | 701篇 |
2009年 | 663篇 |
2008年 | 1026篇 |
2007年 | 1041篇 |
2006年 | 978篇 |
2005年 | 995篇 |
2004年 | 853篇 |
2003年 | 775篇 |
2002年 | 706篇 |
2001年 | 154篇 |
2000年 | 109篇 |
1999年 | 127篇 |
1998年 | 138篇 |
1997年 | 108篇 |
1996年 | 93篇 |
1995年 | 82篇 |
1994年 | 64篇 |
1993年 | 54篇 |
1992年 | 64篇 |
1991年 | 52篇 |
1990年 | 50篇 |
1989年 | 57篇 |
1988年 | 41篇 |
1987年 | 36篇 |
1986年 | 27篇 |
1985年 | 24篇 |
1984年 | 34篇 |
1983年 | 30篇 |
1982年 | 33篇 |
1981年 | 39篇 |
1980年 | 32篇 |
1979年 | 18篇 |
1978年 | 19篇 |
1977年 | 15篇 |
1976年 | 17篇 |
1975年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
George Triadafilopoulos M.D. F.A.C.G. Alex Asian M.D. 《The American journal of gastroenterology》1991,86(8):952-955
Performance of same-day upper and lower endoscopy has many potential advantages, as it may reduce costs, shorten hospital stay, and expedite patient care, but its feasibility, efficacy, and potential have not been carefully defined. We report here our experience with a group of 87 patients who underwent same-day upper and lower endoscopy (174 procedures) over a 2-yr period at a tertiary care VA Hospital, compared with an alternate-day upper and lower endoscopy group of 50 patients (100 procedures) over the same time period. Most patients were elderly males. Common indications for endoscopy were occult or overt gastrointestinal bleeding, previous or concomitant history of pertinent pathology (i.e., polyps, ulcers), abdominal pain, diarrhea, or other symptoms, abnormal radiological studies, and iron deficiency anemia. Both groups required similar amounts of intravenous sedation. There were no complications in either group. In both groups, common positive findings were inflammation (i.e., colitis, esophagitis), benign neoplasms, diverticulae, peptic ulcer, and cancer. In both groups, only 2-6% had negative upper and lower endoscopy, whereas either one procedure was negative in 25% and 18% of cases, respectively. We conclude that the practice of same-day inpatient upper and lower endoscopy is feasible, has excellent diagnostic yield, even in the elderly, and carries no increased risks. When indicated, the practice of same-day upper and lower endoscopy should be encouraged. 相似文献
44.
Summary. Bone mineralisation during and after limb lengthening procedures on the femur or tibia using unilateral fixators has been
monitored quantitatively using dual energy X-ray absorptiometry (DEXA). We measured the bone mineral density (BMD) prospectively
in the newly formed callus, in the bone adjacent to the callus and in the proximal femur. In twenty-one patients we showed
a typical course with a peak value at 4 – 6 weeks after beginning distraction and a minimum value at maximum distraction.
In the consolidation period the BMD in the distraction gap increased until the fixator was removed. The BMD in the regenerated
bone increased faster in the regions of interest (ROI) opposite the fixator compared to those near it. Dynamisation caused
more homogeneous regeneration equalising V
BMD
in the different ROIs. The BMD in the proximal femur of the leg which was operated on decreased to 67% and in the opposite
leg to 87% of the preoperative value. DEXA provides a precise and quantitative assessment of callus and bone mineralisation
during limb lengthening and helps in understanding what is happening during these procedures.
Accepted: 11 July 1996 相似文献
Résumé. Le processus de la minéralisation peut précisément être étudié d’une manière quantitative pendant et après la distraction du cal au moyen de l’absorptiométrie en énergie-binaire (DEXA) en créant une petite radioexposition. Des patients (n = 21) avec une distraction du cal, auxquels nous avons mesuré prospectivement la densité minérale de l’os (bone mineral density = BMD) dans et autour du cal nouvellement formé, étaient traités avec des fixateurs externes unilatéraux. La minéralisation a montré une courbe typique avec une première pointe de valeur [0,365 +/– 0,196 g/cm 2 (30,9% de la première valeur)] à 4 – 6 semaines après le début de la distraction. Une valeur minimale apparut à la distraction maximale. Dans la période de consolidation la BMD est montèe jusqu’au moment de l’enlèvement du fixateur à 1,020 +/– 0,234 g/cm2 (87%). La minéralisation du cal, mésurée grace à la technique des ?regions of interest (ROIs)?, augmenté plus vite aux ROIs éloignées qu’aux ROIs très proches du fixateur. De la dynamisation du fixateur résulte une vitesse de minéralisation plus homogène. Nous considérons la DEXA comme une méthode précise pour étudier les processus de la minéralisation et du développement du cal pendant la distraction avec un fixateur unilatéral. En tenant compte des limites de la technique, la DEXA – qui nous livre des valeurs quantitatives – nous aide à comprendre ce qui se passe pendant la distraction.
Accepted: 11 July 1996 相似文献
45.
Laparoscopic Cholecystectomy for Acute Cholecystitis: Prospective Trial 总被引:23,自引:0,他引:23
Samuel Eldar Edmond Sabo Ernest Nash Jack Abrahamson Ibrahim Matter 《World journal of surgery》1997,21(5):540-545
p
< 0.00001) and for hydrops (28.5%) and empyema of the gallbladder
(28.5%) (
p
= 0.004). The difference in conversion
between the group with acute necrotizing (gangrenous) cholecystitis and
the two groups with hydrops and empyema of the gallbladder was not
statistically significant (
p
= 0.07). The complication
rates of acute cholecystitis, hydrops, empyema of the gallbladder, and
gangrenous cholecystitis were 9.0%, 9.5%, 14.0%, and 20.0%,
respectively (
p
= NS). Patients with an operative
delay of 96 hours or less from the onset of acute cholecystitis had a
conversion rate of 23%, whereas a delay of more than 96 hours was
associated with a conversion rate of 47% (
p
= 0.022).
The complication rate was 8.5% in the laparoscopic group and 27% in
the converted group (
p
= 0.013). Patients over 65
years of age, with a history of biliary disease, a nonpalpable
gallbladder, WBC count over 13,000/cc, and acute gangrenous
cholecystitis were independently associated with a high LC conversion
rate; male patients, finding large bile stones, serum bilirubin over
0.8 mg/dl, and WBC count over 13,000/cc were independently associated
with a high complication rate following laparoscopic surgery with or
without conversion. Generally, LC can be performed safely for acute
cholecystitis, with acceptably low conversion and complication rates.
Different forms of cholecystitis carry various conversion and
complication rates in selected cases. LC for acute cholecystitis should
be performed within 96 hours of the onset of disease. Predictors of
conversion and complications may be helpful when planning the
laparoscopic approach to acute cholecystitis. 相似文献
46.
47.
48.
The Physical Inactivity Matrix: Lessons from the classification of physical inactivity interventions
Kypros Kypri Alex Donaldson Elizabeth Johnstone 《Journal of Science and Medicine in Sport》2006,9(1-2):98-102
Physical inactivity (PI), a leading modifiable cause of disease and injury, is endemic in industrialised nations. Although considerable research has been undertaken in this field, we lack a system to synthesise the research literature to inform policy and identify research needs. The aims of this study were to (1) develop a system to classify physical inactivity intervention studies, (2) examine the distribution of PI interventions published in the peer-reviewed health literature using the system, and (3) consider implications for future research. We developed the Physical Inactivity Matrix (PIM), with 12 intervention points, created by the intersection of two dimensions: the intervention target (individual, physical environment and social/cultural environment) and the activity focus (transport, work/school, leisure and consumer). A formal search of the health research literature identified 529 eligible studies and each was classified into one of the 12 cells of the PIM. Most studies were categorised as: individual-leisure (68%), individual-work/school (12%) or social/cultural environment-leisure (13%). Only 4% targeted the physical environment. The findings of this initial application of the PIM support the call for greater investment in policies, interventions and research that focus on the relationship between the environment and PI, and transportation in particular. There would be merit in establishing the inter-rater reliability of the PIM and applying it to a wider variety of studies, including those published in the transportation and urban planning literatures. The PIM could be a useful tool for monitoring trends in research directions and funding levels over time and across countries. 相似文献
49.
The utility of MRI using magnetization transfer (MT) enhanced pulse sequences to diagnose hepatic cirrhosis in a rat model was investigated. Hepatic T1 was measured with and without MT off-resonance RF pulses in 17 treated and six control rats. The livers were evaluated histologically, and the hydroxyproline content quantitatively measured. We did not find a statistically significant linear correlation between the MR relaxation times and the degree of tissue injury. However, the MR measurements performed with MT were superior to those without differentiating the treated and control groups. Specifically, the T1 times were 695 ±76 ms for the treated group, versus 748 ± 61 ms in the controls; P= 0.095. The T1sat times were also lower in the treated group, with statistical significance: 367 ± 51 ms versus 421 ± 38 ms, P = 0.016. Finally, the change in the relaxation rates (the inverse of the relaxation times) with and without saturation were 1.31 ± 0.22 s?1 (treated group) versus 1.05 ± 0.12 s?1 (controls), which differed significantly, P= 0.001. 相似文献
50.
The therapeutic antibodies market to 2008. 总被引:7,自引:0,他引:7
Alex K Pavlou Mark J Belsey 《European journal of pharmaceutics and biopharmaceutics》2005,59(3):389-396
The therapeutic biologics market is currently dominated by recombinant protein products. However, many of these products are mature, and growth of the biologics market will increasingly rely on the expansion of the therapeutic monoclonal antibody sector. Successive technology waves have driven the growth of the monoclonal antibody sector, which is currently dominated by chimeric antibodies. Chimeric products, led by Remicade and Rituxan, will continue to drive market share through to 2008. However, over the forecast period, humanized and fully human monoclonal antibodies, together with technologies such as Fabs and conjugated antibodies, will play an increasingly important role, driving monoclonal antibody market growth at a forecast compound annual growth rate of 20.9%, to reach $16.7 billion by 2008. In terms of therapeutic focus, the monoclonal antibody market is heavily focused on oncology and arthritis, immune and inflammatory disorders, and products within these therapeutic areas are set to continue to be the key growth drivers over the forecast period. Underlying the growth of the market is the evolution of the monoclonal antibody company business model, set to transition towards the highly successful innovator model. 相似文献