全文获取类型
收费全文 | 1052021篇 |
免费 | 79053篇 |
国内免费 | 2756篇 |
专业分类
耳鼻咽喉 | 13689篇 |
儿科学 | 35977篇 |
妇产科学 | 29819篇 |
基础医学 | 154221篇 |
口腔科学 | 29125篇 |
临床医学 | 95553篇 |
内科学 | 204368篇 |
皮肤病学 | 23748篇 |
神经病学 | 84269篇 |
特种医学 | 40678篇 |
外国民族医学 | 350篇 |
外科学 | 156493篇 |
综合类 | 24117篇 |
一般理论 | 455篇 |
预防医学 | 82213篇 |
眼科学 | 23705篇 |
药学 | 75797篇 |
3篇 | |
中国医学 | 2173篇 |
肿瘤学 | 57077篇 |
出版年
2018年 | 11564篇 |
2017年 | 8935篇 |
2016年 | 10189篇 |
2015年 | 11556篇 |
2014年 | 15593篇 |
2013年 | 24045篇 |
2012年 | 31600篇 |
2011年 | 33551篇 |
2010年 | 20425篇 |
2009年 | 19091篇 |
2008年 | 31242篇 |
2007年 | 33010篇 |
2006年 | 33514篇 |
2005年 | 32042篇 |
2004年 | 31409篇 |
2003年 | 30039篇 |
2002年 | 29073篇 |
2001年 | 48559篇 |
2000年 | 49727篇 |
1999年 | 41818篇 |
1998年 | 11940篇 |
1997年 | 10716篇 |
1996年 | 10694篇 |
1995年 | 10335篇 |
1994年 | 9567篇 |
1993年 | 8984篇 |
1992年 | 33411篇 |
1991年 | 32605篇 |
1990年 | 32111篇 |
1989年 | 30977篇 |
1988年 | 28071篇 |
1987年 | 28231篇 |
1986年 | 26323篇 |
1985年 | 25397篇 |
1984年 | 18982篇 |
1983年 | 16073篇 |
1982年 | 9680篇 |
1981年 | 8749篇 |
1979年 | 17389篇 |
1978年 | 12531篇 |
1977年 | 10617篇 |
1976年 | 10017篇 |
1975年 | 10508篇 |
1974年 | 12682篇 |
1973年 | 12134篇 |
1972年 | 11175篇 |
1971年 | 10377篇 |
1970年 | 9592篇 |
1969年 | 8925篇 |
1968年 | 8251篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Upper airway obstruction due to inoperable intrathoracic goitre treated by tracheal endoprosthesis. 下载免费PDF全文
M Noppen M Meysman E Dhondt L Gepts B Velkeniers L Vanhaelst W Vincken 《Thorax》1994,49(10):1034-1036
Thyroidectomy is the treatment of choice in patients with thyroid enlargement complicated by compression or displacement of the trachea because of the risk of complete airway obstruction due to sudden enlargement of the goitre by, for example, haemorrhage. In patients who are medically inoperable an endoscopically inserted tracheal endoprosthesis may provide longstanding airway patency, as reported here. 相似文献
992.
The physiological phenomenon of changes in callus formation during distraction was first described by Codivilla at the beginning of this century. Having investigated and proved the influence of tension stress on callus formation, Ilizarov used this as a method to treat limb shortening and deformities. Because of his remarkable results we introduced this method in our hospital in 1990, using the original Ilizarov ring fixator. From November 1990 to December 1991, we used this technique in 10 cases of combined post-traumatic bone shortening with deformity (the tibia was affected in six patients, the femur in three and the forearm in one). The mean shortening was 3.1 cm, the mean varus or valgus deformity 9.5 degrees, the mean anteflexion or recurvation 8.3 degrees, and the mean rotation deformity 8.5 degrees. Distraction/correction lasted between 8 and 55 days (mean: 37 days). Fixation was necessary for between 60 and 339 days. If corticotomy was performed in the diaphyseal bone, fixation lasted almost twice as long (11.33 days/mm lengthening) as in the metaphyseal area (6.55 days/mm lengthening). There were 14 complications, most of which were considered minor. The latter included pin infections (4), wire breaking (1) and restricted range of motion of the knee or ankle (5). Among the major complications were two nerve irritations, which recovered spontaneously, and two pin-induced local bone infections, which required surgical intervention. Achievement of the goals of treatment-complete correction of shortening and deformity-was not affected by these complications. 相似文献
993.
To determine the influence of the duration of postoperative lumbar immobilization with the aid of a rigid lumbar orthosis on the consolidation of posterolateral lumbosacral fusions, 22 patients with no previous osseous spinal surgery and with fusion without osteosynthesis due to spondylolysis-olisthesis Grade 1 to 2 or intervertebral disc or facet joint disorder were examined by roentgen stereophotogrammetric analysis in supine and erect positions and by conventional radiography for 1 year after surgery. In Series 1, patients (n = 11) were instructed to keep the trunk straight with the aid of a molded, rigid lumbar orthosis for 5 months after surgery; and in Series 2 (n = 11), the same instructions were given, but for 3 months. In Series 1, osseous fusion was seen on radiographs in eight patients. In these patients, the intervertebral translations between the fused vertebrae began to decrease 3-6 months after surgery, and within 1 year, the fusions became rigid, as defined by roentgen stereophotogrammetric analysis, or intervertebral translations of mostly less than 1 mm persisted. In three patients with poor fusion still seen on radiographs 1 year after surgery, no rigid fusion was obtained and intervertebral translations of up to 10 mm persisted. In Series 2, a similar roentgen stereophotogrammetric analysis pattern was noted in two patients with osseous fusion and in seven with poor fusion seen on radiographs. The fusion was radiographically doubtful in two patients. In these patients, the intervertebral translations decreased, but translations of 1.5 mm persisted 1 year after surgery.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
994.
N B Watts 《Southern medical journal》1992,85(8):2S31-2S33
Bisphosphonates are agents that are potentially useful for treatment of osteoporosis. They are antiresorptive agents, increasing bone mass by decreasing the frequency of osteoclast activation or the depth of osteoclast resorption, or both. Intermittent cyclical therapy with etidronate has been shown to be effective for postmenopausal osteoporosis in two controlled studies. Several second- and third- generation bisphosphonates are undergoing active clinical trials. 相似文献
995.
A B Holmlund G Gynther F P Reinholt 《Oral surgery, oral medicine, and oral pathology》1992,73(3):273-277
Consecutive patients with clinical diagnoses of disk derangement and rheumatoid arthritis with temporomandibular joint (TMJ) signs and symptoms were compared by clinical, radiographic, and arthroscopic examination. Synovial biopsies were obtained from patients with arthroscopic features of synovial inflammation. No clinical sign or symptom was found to be specific of rheumatoid involvement although joint crepitation was most frequently found in rheumatic patients (p less than 0.001). Tomographic features of subchondral bone involvement were more frequently revealed in TMJs of rheumatic patients (p less than 0.001). At arthroscopy rheumatic patients often showed pronounced arthrotic changes and inflammation. In contrast to patients with disk derangement, fibrosis of the TMJ was frequent (p less than 0.001). Histologic examination of obtained synovial specimens correlated well with arthroscopic findings, and more pronounced inflammation was present in specimens from rheumatic patients. 相似文献
996.
997.
998.
Lipodermatosclerosis is a sign of severe chronic venous insufficiency. In this stage of CVI one can find capillary leakage of water and plasmaproteins which results in a higher capillary filtration rate. In skin biopsies the result of this process can be seen as a pericapillary halo. The group of Burnand recently described fibrinogen deposits in this area. We studied the capillaries and their surrounding tissue to determine the thickness of the collagen IV deposits. In severe CVI with lipodermatosclerosis a significant increase of the collagen IV layer was observed. Collagen IV thickness was measured by an index method. The collagen IV thickness for this purpose refers to the capillary diameter. It can be suggested that the increase of the venous pressure in the capillaries leads to leakage of several proteins and namely fibrinogen. As a result of the increase of fibrinogen the collagen IV layer becomes thicker which leads to a decreasing function of the capillaries. In this way an auto-amplification mechanism maintains CVI. An other explanation can be induction of collagen IV due to the high capillary pressure in CVI. 相似文献
999.
U Dietz R Erbel B Pannen M Haude U Nixdorff S Iversen W Thoenes D Auth J Meyer 《Zeitschrift für Kardiologie》1991,80(3):222-229
High-frequency rotational angioplasty is a recently developed method for coronary angioplasty in the catheter laboratory. An elliptical burr tip (phi 1.25-2.0 mm) with embedded diamant chips (phi 40-50 microns) is rotated by a helical drive shaft at 150,000-180,000 rpm. The burr is advanced over a 0.009-inch coaxial guide wire. To show the effects of this approach in diseased and healthy vessels, which may be present before and behind a stenosis, 17 atherosclerotic coronary arteries of nine human hearts, and 18 normal coronary arteries of nine pig hearts were treated by this method in vitro. Standardized coronary angiography was performed before and after Rotablator treatment, followed by histological examination. From these data the burr-to-vessel-diameter ratio was calculated for each vessel segment and compared with the angiographical and histological outcome. Partial or complete removal of the circumference of the innermost vessel wall layers was observed regularly. The average removal of tissue in human coronary arteries was limited to the intimal layer and in the pig coronary arteries to the internal elastic membrane. In the pig coronary arteries no intimal tears or dissections occurred, in human coronary arteries tears could be seen frequently (13 of 17 vessels (76%)). Media tears were observed in 3 of 17 vessels; one (2%) media dissection could be demonstrated; no perforation occurred. Thus, the in vitro studies suggest that coronary rotational angioplasty has only a slight effect on the vessel segment next to a stenosis, regardless of the burr-to-vessel-diameter ratio.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
1000.