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   243127篇
  免费   15379篇
  国内免费   999篇
耳鼻咽喉   2591篇
儿科学   6190篇
妇产科学   4580篇
基础医学   30432篇
口腔科学   4465篇
临床医学   24913篇
内科学   51090篇
皮肤病学   3327篇
神经病学   24455篇
特种医学   10429篇
外国民族医学   39篇
外科学   38264篇
综合类   2602篇
现状与发展   1篇
一般理论   179篇
预防医学   17106篇
眼科学   5720篇
药学   15997篇
  1篇
中国医学   334篇
肿瘤学   16790篇
  2023年   1358篇
  2022年   2254篇
  2021年   5424篇
  2020年   3116篇
  2019年   5160篇
  2018年   6180篇
  2017年   4566篇
  2016年   4985篇
  2015年   5867篇
  2014年   8551篇
  2013年   11546篇
  2012年   17610篇
  2011年   18381篇
  2010年   10293篇
  2009年   9504篇
  2008年   16211篇
  2007年   16972篇
  2006年   16499篇
  2005年   16342篇
  2004年   15394篇
  2003年   14068篇
  2002年   13503篇
  2001年   2214篇
  2000年   1722篇
  1999年   2249篇
  1998年   2893篇
  1997年   2293篇
  1996年   1984篇
  1995年   1828篇
  1994年   1571篇
  1993年   1537篇
  1992年   1147篇
  1991年   1084篇
  1990年   947篇
  1989年   883篇
  1988年   813篇
  1987年   735篇
  1986年   763篇
  1985年   807篇
  1984年   1004篇
  1983年   861篇
  1982年   1092篇
  1981年   1019篇
  1980年   870篇
  1979年   528篇
  1978年   575篇
  1977年   504篇
  1976年   472篇
  1975年   362篇
  1974年   378篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

Background  

Skin and soft tissue infections are increasingly prevalent clinical problems, and it is important for health care practitioners to be well trained in how to treat skin abscesses. A realistic model of abscess incision and drainage will allow trainees to learn and practice this basic physician procedure.  相似文献   
52.
Background: Dreaming reported after anesthesia remains a poorly understood phenomenon. Dreaming may be related to light anesthesia and represent near-miss awareness. However, few studies have assessed the relation between dreaming and depth of anesthesia, and their results were inconclusive. Therefore, the authors tested the hypothesis that dreaming during anesthesia is associated with light anesthesia, as evidenced by higher Bispectral Index values during maintenance of anesthesia.

Methods: With approval, 300 consenting healthy patients, aged 18-50 yr, presenting for elective surgery requiring relaxant general anesthesia with a broad range of agents were studied. Patients were interviewed on emergence and 2-4 h postoperatively. The Bispectral Index was recorded from induction until the first interview. Dream content and form were also assessed.

Results: Dreaming was reported by 22% of patients on emergence. There was no difference between dreamers and nondreamers in median Bispectral Index values during maintenance (37 [23-55] vs. 38 [20-59]; P = 0.68) or the time at Bispectral Index values greater than 60 (0 [0-7] vs. 0 [0-31] min; P = 0.38). Dreamers tended to be younger and male, to have high home dream recall, to receive propofol maintenance or regional anesthesia, and to open their eyes sooner after surgery. Most dreams were similar to dreams of sleep and were pleasant, and the content was unrelated to surgery.  相似文献   

53.
For chronic thromboembolic pulmonary hypertension not amenable to pulmonary endarterectomy, effective medical therapy is desired. In an open-label uncontrolled clinical trial, 104 patients (mean +/- sem age 62 +/- 11 yrs) with inoperable chronic thromboembolic pulmonary hypertension were treated with 50 mg sildenafil t.i.d. At baseline, patients had severe pulmonary hypertension (pulmonary vascular resistance 863 +/- 38 dyn.s.cm(-5)) and a 6-min walking distance of 310 +/- 11 m. Eight patients were in World Health Organization functional class II, 76 in class III and 20 in class IV. After 3 months' treatment, there was significant haemodynamic improvement, with reduction of pulmonary vascular resistance to 759 +/- 62 dyn.s.cm(-5). The 6-min walking distance increased significantly to 361 +/- 15 m after 3 months' treatment, and to 366 +/- 18 m after 12 months' treatment. A subset of 67 patients received a single dose of 50 mg sildenafil during initial right heart catheterisation. The acute haemodynamic effect of this was not predictive of long-term outcome. In this large series of patients with inoperable chronic thromboembolic pulmonary hypertension, open-label treatment with sildenafil led to significant long-term functional improvement. The acute effect of sildenafil may not predict the long-term outcome of therapy.  相似文献   
54.
Abstract Background: Primary shoulder hemiarthroplasty is an established treatment modality for complex fractures of the proximal humerus. Long-term functional outcome is often disappointing. However, little is known about social implications particularly in the elderly. Methods: A single-institution case series of consecutive geriatric patients (age > 70 years) treated with shoulder hemiarthroplasty for complex fractures of the proximal humerus between 1994 and 1997 was analysed. Postoperative morbidity, long-term function, radiological outcome and social implications were evaluated. Results: Seventy-seven patients fulfilled the study criteria. Median age at the time of operation was 80 years (range 70–93 years). Systemic and local postoperative complications were observed in 8% including 2 patients (3%) with revision surgery. Postoperative mortality was 1%. Forty-eight patients (62%) were available for follow-up (median 49 months, range 25–80 months), 22 (29%) died from causes unrelated to hemiarthroplasty before follow-up and 7 patients (9%) did not attend follow-up examination. Median Constant-Murley score was 41 points (range 17–77 points). Long-term results concerning pain were satisfying. The Oxford shoulder score ranged from 14 to 40 (median 30). Forty-one patients (85%) still lived in their original environment and managed their daily life independently despite poor shoulder function. Four patients (8%) lived in a retirement home and 3 (6%) in a nursery home. Eighty percent of our patients were still able to use public transportation, do the daily shopping and wash their whole body by themselves. Conclusion: Most patients managed their daily life independently despite poor shoulder function.  相似文献   
55.
OBJECTIVE: Pamidronate has been studied as a therapeutic drug for various osteopenic diseases. However, avascular osteonecrosis in the jawbone has been recently reported in patients receiving pamidronate. The objective of this study was to examine the effect of pamidronate on bone regeneration in a controlled animal model. MATERIALS AND METHODS: To determine the effect of parmidronate on bone healing in a local bony defect area, a rabbit calvarial bony defect model was used and poly L-lactide-co-glycolide (PLGA) used as a drug carrier material. Four defect groups were made in each rabbit calvaria and the defects were treated as follows: untreated bony defect (group 1), PLGA only (group 2), 2 mg of pamidronate with PLGA (group 3), and 3 mg of pamidronate with PLGA (group 4). Bone healing was evaluated by radiography and histology at 1, 2, 4, 6, and 8 weeks after surgery. RESULTS: In radiographic analysis, radiopacity was lower in pamidronate groups than non-operated rabbit calvarial bone at all observation points (P < .05). In histological analysis, the initial bone formation at 1 week was not different among groups, but it was much lower in the pamidronate groups than in the control or PLGA group after 2 weeks. Newly formed bone at 1 week underwent avascular necrosis after 2 weeks in both pamidronate groups. Avascular necrosis was not observed until 8 weeks in both topically applied pamidronate groups. CONCLUSION: Collectively, pamidronate inhibits bone healing in rabbit calvarial bony defect and it may explain the avascular necrosis of the jaws in patients receiving pamidronate.  相似文献   
56.
The purpose of the present study was to evaluate the haemostatic efficacy of fibrin sealant in patients with hereditary haemorrhagic telangiectasia (HHT) or Rendu-Osler-Weber disease suffering epistaxis. A retrospective observational study of patients with HHT who were admitted to an emergency room for anterior or posterior epistaxis during May 2000-March 2003. A total of 24 patients were evaluated, of whom 15 were managed with foam nasal packing during May 2000-March 2002 and another nine were treated during March 2002-March 2003 with 0.3 ml fibrin sealant spray (Quixil; Omrix, Belgium). The immediate and the distant results were compared. Immediate haemostasis was achieved in all seven patients treated with fibrin glue, with good healing of bleeding sites, no secondary bleeding, no inflammation, and no plaque or crists. Twelve months of follow-up monitoring (until October 2003) of atrophic changes of nasal mucosa, bleeding frequency and intensity proved absence of atrophy of nasal mucosa and decreased bleeding frequency. In this group, the bleeding episode duration averaged 2 min 35 s since the moment of admittance. In the nasal packing group, we found local swelling, pain, and slow healing of the bleeding site with accidental atrophy of nasal mucosa and no effect on further bleeding frequency and intensity. Removal of nasal packing frequently initiates secondary bleeding. The rates of these side effects were higher in comparison with the fibrin glue group. The bleeding episode duration was also longer. In patients with HHT suffering profuse epistaxis, fibrin glue is more effective and convenient for the patients as compared with foam nasal packing. It is also safer, since it lacks the complications that usually accompany packing as swelling, atrophy of the nasal mucosa, and secondary bleeding provoked by the removal of the pack.  相似文献   
57.
58.
We evaluated the consistency of three questionnaire methods of assessing work and leisure activity in the rural biethnic population of the San Luis Valley Diabetes Study. A 7-d physical activity recall (PAR), a ranking of usual activity, and a history of usual participation in vigorous activity were used. Energy expenditure (kJ.kg-1.wk-1) (EE) was estimated from PAR. Subjects were 503 adults [49% non-Hispanic white (NHW), 51% Hispanic]. Physical activity at work rather than leisure-time activity largely determined total energy expenditure. Average EE at work increased with work rank for all subjects combined [mean EE (SEE) for rank 1 (low) = 324.2 (24.4), rank 4 (high) = 874.0 (102.1)] and within sex, ethnic, and occupational subgroups. Leisure EE increased with leisure rank only for NHW men and employed women. Similar patterns were observed in comparisons of PAR data with history of vigorous activity. Further development and validation of instruments appropriate for use across population subgroups are needed.  相似文献   
59.
An empirical investigation of the perceived role of robotics and artificial computer intelligence in the future of health care reveals factors favoring a positive attitude by health administrators. The study employed a two-part survey administered in late 1989 and early 1990 to health care managers in hospitals and nursing homes. Part One of the survey asked about the participant, his or her work habits and work environment. Part Two obtained a psychological profile of rationality vs. intuition in problem solving. Through bivariate and multivariate post hoc statistical tests, we discovered the following variables which significantly determined attitudes toward robotics and artificial computer intelligence: sex, number of employees supervised; perceptions of waste and inefficiency in the workplace; perceptions of time-consuming personnel problem; perceived need to make more efficient use of time, money, and facilities; and perceived favorable climate for innovation. Among the factors which did not have an effect on attitudes toward advanced technology were three measures of rationality vs. intuition in problem solving.  相似文献   
60.
Tuberculosis involving the soft tissue from adjacent bone or joint is well recognized. However, primary tuberculous pyomyositis, tuberculous bursitis, and tuberculous tenosynovitis are rare entities constituting 1% of skeletal tuberculosis. Tuberculous tenosynovitis involves most commonly the tendon sheaths of the hand and wrist, and tuberculous bursitis occurs most commonly around the hip. The greater trochanteric bursa and the greater trochanter are the most frequent sites of tuberculous bursitis. Cases of primary tuberculous pyomyositis and tenosynovitis of the tendons of the ankle and foot are seldom reported in the radiology literature. All imaging modalities-plain radiography, bone scan, computed tomography, and magnetic resonance imaging (MRI)--provide information that is helpful in determining therapy. MRI in particular, with its multiplanar capabilities and superb contrast of soft tissue, can demonstrate the extent of the soft tissue mass and access the adjacent bones and joints. However, MRI has no diagnostic specificity in regard to tuberculosis, and in nonendemic areas, biopsy is strongly recommended. All patients in this review were permanent residents of North America or Western Europe and were immunocompetent. Examples of atypical presentations of the above entities are demonstrated.  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