全文获取类型
收费全文 | 1595592篇 |
免费 | 115587篇 |
国内免费 | 3639篇 |
专业分类
耳鼻咽喉 | 20987篇 |
儿科学 | 53693篇 |
妇产科学 | 43407篇 |
基础医学 | 238130篇 |
口腔科学 | 45343篇 |
临床医学 | 144714篇 |
内科学 | 305481篇 |
皮肤病学 | 36443篇 |
神经病学 | 121054篇 |
特种医学 | 60299篇 |
外国民族医学 | 376篇 |
外科学 | 238139篇 |
综合类 | 36350篇 |
现状与发展 | 2篇 |
一般理论 | 522篇 |
预防医学 | 121892篇 |
眼科学 | 36892篇 |
药学 | 117859篇 |
6篇 | |
中国医学 | 4102篇 |
肿瘤学 | 89127篇 |
出版年
2018年 | 17096篇 |
2017年 | 13301篇 |
2016年 | 14999篇 |
2015年 | 16794篇 |
2014年 | 22930篇 |
2013年 | 34878篇 |
2012年 | 46103篇 |
2011年 | 48877篇 |
2010年 | 29166篇 |
2009年 | 27467篇 |
2008年 | 45574篇 |
2007年 | 48662篇 |
2006年 | 49383篇 |
2005年 | 46908篇 |
2004年 | 45798篇 |
2003年 | 43900篇 |
2002年 | 42528篇 |
2001年 | 76922篇 |
2000年 | 78805篇 |
1999年 | 65518篇 |
1998年 | 17928篇 |
1997年 | 15681篇 |
1996年 | 16000篇 |
1995年 | 15246篇 |
1994年 | 14098篇 |
1993年 | 13147篇 |
1992年 | 51539篇 |
1991年 | 50598篇 |
1990年 | 49651篇 |
1989年 | 48498篇 |
1988年 | 44138篇 |
1987年 | 43662篇 |
1986年 | 41025篇 |
1985年 | 39379篇 |
1984年 | 29170篇 |
1983年 | 24652篇 |
1982年 | 14299篇 |
1981年 | 12826篇 |
1979年 | 26761篇 |
1978年 | 19161篇 |
1977年 | 16134篇 |
1976年 | 15398篇 |
1975年 | 16481篇 |
1974年 | 19682篇 |
1973年 | 18891篇 |
1972年 | 17582篇 |
1971年 | 16304篇 |
1970年 | 15397篇 |
1969年 | 14303篇 |
1968年 | 13203篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Laparoscopic surgery has several advantages over traditional surgery because it has been shown to be less invasive. The next logical step in the evolution of minimally invasive surgery may be to eliminate all abdominal incisions. The natural orifices provide a port of entry via the gastrointestinal tract to the peritoneal cavity. This approach would require the creation of a perforation, which is considered to be a major complication of endoscopy with significant morbidity and mortality. However, there are several recent studies that have described the technical feasibility and safety of a per‐oral transgastric approach to the peritoneal cavity using conventional endoscopes. Theoretically, this approach could reduce postoperative abdominal wall pain, wound infection, hernia formation, and adhesions. This article aims to summarize the current status of transgastric surgery, currently referred to as natural orifice transluminal endoscopic surgery (NOTES), and to address some of its future challenges. 相似文献
32.
N. SUVAJD
I V. EMERIKI‐MARTINOVI . ARANOVI M. PETROVI M. POPOVI V. ARTIKO M. UPI I. ELEZOVI 《International journal of laboratory hematology》2006,28(5):317-320
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed. 相似文献
33.
34.
G Steinitz M C Martín N Gazit-Yaari M L Quesada J de la Nuez R Casillas U Malik Z B Begin 《Applied radiation and isotopes》2006,64(4):520-524
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes. 相似文献
35.
D B Irving J L Cook H B Menz 《Journal of Science and Medicine in Sport》2006,9(1-2):11-22; discussion 23-4
36.
A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective (CHESS) presaturation pulses. 相似文献
37.
38.
A-C Koschker M Fassnacht S Hahner D Weismann B Allolio 《Experimental and clinical endocrinology & diabetes》2006,114(2):45-51
BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly malignant tumour with a poor prognosis. Patients present with signs of steroid hormone excess (e.g., Cushing's syndrome) or symptoms due to an abdominal mass. DIAGNOSIS: In case of an adrenal mass, hormonal workup before surgery is required for differential diagnosis, perioperative management, and for follow-up. The imaging of choice is CT or MRI with MRI being of additional use when invasion of big vessels is suspected. Apart from that, the use of 18-FDG-PET is becoming increasingly established. TREATMENT: Surgical resection is the therapeutic option of choice in stages 1 - 3. In stage 4, the adrenolytic compound mitotane is part of the first-line treatment, but often needs to be combined with cytotoxic chemotherapy. Most patients will eventually have a recurrence, so adjuvant treatment (mitotane/tumour bed radiation) has to be considered in high risk patients, even if randomized controlled trials on adjuvant treatment are still lacking. STRUCTURAL PROGRESS: Several national and European structures have recently been established in order to increase our knowledge of ACC, improve therapeutic options and diagnostic procedures, and promote research. GANIMED, as a Germany-wide network of experts on adrenal diseases, has been founded allowing for improved gathering of data and joint studies. ENSAT (European Network for the Study of Adrenal Tumours) has been brought to life, aiming at European standards for therapy, diagnosis and tumour banking. Since 2003, patients can be enrolled in the German ACC Registry. France and Italy have also developed a central registry to collect nationwide data from patients with ACC. For the first time, patients with metastatic/unresectable ACC can participate in a prospective controlled randomized trial comparing two different cytotoxic chemotherapy regimes (FIRM-ACT). 相似文献
39.
B Dederichs M Dietlein B Jenniches-Kloth M Schmidt P Theissen D Moka H Schicha 《Experimental and clinical endocrinology & diabetes》2006,114(7):366-370
BACKGROUND: Radioiodine therapy (RIT) combined with glucocorticoids is an effective therapy for Graves' disease, but it is debatable whether glucocorticoids should be applied in patients without Graves' ophthalmopathy (GO). METHODS: The effect of 0.4 - 0.5 mg prednisone every second day over a period of 5 weeks after RIT was monitored over a follow-up period of at least 12 months after RIT. A questionnaire was sent to 186 consecutive patients without GO concerning eye symptoms after RIT. 148 patients (80 %) answered. If eye symptoms had occurred after RIT, additional clinical examination was carried out at our outpatient clinic. The primary endpoint was the absence or onset of GO within the first year after RIT. RESULTS: Within 12 months after RIT the examination confirmed GO in 5 out of 148 patients (3.4 %). In all cases the symptoms were transient. No adverse reaction to the use of prednisone after RIT was noted. CONCLUSIONS: The risk of new GO in the first year after RIT was low and the clinical course of GO was mild when RIT was combined with a low-dose glucocorticoid regimen. Preventive administration of glucocorticoids can therefore be recommended in patients with Graves' disease even without evident GO. 相似文献
40.
M Vitacca M Paneroni L Bianchi E Clini A Vianello P Ceriana L Barbano B Balbi S Nava 《The European respiratory journal》2006,27(2):343-349
The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure. 相似文献