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   36104篇
  免费   1969篇
  国内免费   107篇
耳鼻咽喉   438篇
儿科学   2133篇
妇产科学   715篇
基础医学   4654篇
口腔科学   825篇
临床医学   2539篇
内科学   7320篇
皮肤病学   842篇
神经病学   1912篇
特种医学   803篇
外科学   4969篇
综合类   1328篇
一般理论   16篇
预防医学   2113篇
眼科学   1555篇
药学   3528篇
中国医学   274篇
肿瘤学   2216篇
  2023年   242篇
  2022年   693篇
  2021年   1181篇
  2020年   663篇
  2019年   875篇
  2018年   1070篇
  2017年   732篇
  2016年   972篇
  2015年   1009篇
  2014年   1372篇
  2013年   1761篇
  2012年   2421篇
  2011年   2443篇
  2010年   1380篇
  2009年   1237篇
  2008年   1773篇
  2007年   1740篇
  2006年   1757篇
  2005年   1382篇
  2004年   1383篇
  2003年   1175篇
  2002年   1003篇
  2001年   823篇
  2000年   867篇
  1999年   729篇
  1998年   309篇
  1997年   213篇
  1996年   222篇
  1995年   217篇
  1994年   176篇
  1993年   150篇
  1992年   498篇
  1991年   404篇
  1990年   430篇
  1989年   395篇
  1988年   357篇
  1987年   356篇
  1986年   348篇
  1985年   323篇
  1984年   262篇
  1983年   219篇
  1979年   230篇
  1978年   148篇
  1977年   180篇
  1976年   139篇
  1975年   171篇
  1974年   182篇
  1973年   182篇
  1972年   173篇
  1971年   161篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
OBJECTIVE: VATS using the conventional three ports is currently the technique of choice for blebectomy/bullectomy for spontaneous pneumothorax. However, the procedure has recently been shown to have neurological complications related to the port sites. Uniportal VATS has recently been proposed as an alternative to conventional three-port VATS. It is anticipated that the single incision will predispose to a lower incidence of neurological complications. METHODS: We report our initial single surgeon experience of uniportal VATS (n = 16) and provide a comparison of post-operative pain and residual paraesthesia to conventional three-port procedures (n = 19) for the same pathology. RESULTS: In both groups, the pneumothorax pathology was principally primary. There was no difference between the groups in terms of age, spirometry, tissue resected, drainage time and inpatient stay. A difference was, however, noted in inpatient pain scores. The uniportal group had a lower median score of 0.4 (visual analogue range 0-4) while the three-port technique reported 0.8 (P = 0.06, Mann-Whitney test). The maximum score trend was similar (1.4 vs. 2.6, respectively, P < 0.001, Mann-Whitney test). Follow-up for uniportal and three-port VATS averaged 9.4+/-6.6 and 32.1+/-9.9 months, respectively. One patient in the three-port group had a pneumothorax recurrence. Three-port VATS also had a higher residual pain score (0.5) compared to uniportal VATS (0.3). Of clinical significance was the incidence of neurological complications. Eighty-six percent of uniportal patients reported no symptoms. The remaining experienced only mild 'numbness' or 'swelling'. However, in the three-port group, only 42% reported no symptoms. A similar number experienced 'numbness'. Two females described sexual dysfunction due to altered breast sensitivity. Seventeen percent (2/12) reported 'pins and needles'. CONCLUSIONS: Uniportal VATS appears to be tolerable, safe and efficient in treating spontaneous pneumothorax in our series. Moreover, post-operative pain and paraesthesia incidence was lower than three-port VATS. Prospective randomised trials are important to evaluate this technique.  相似文献   
42.
Serum samples obtained from human immunodeficiency virus (HIV)-infected tuberculosis (TB) patients months prior to clinical TB were used to delineate the profile of Mycobacterium tuberculosis culture filtrate proteins recognized during subclinical TB. A subset of ~12 antigens was recognized by antibodies in these serum samples. Antibodies to two of these antigens (81 [88]-kDa malate synthase [GlcB] and MPT51) were present in serum samples obtained during incipient subclinical TB in 19 (~90%) of the 21 HIV-infected TB patients tested. These antigens will be useful for devising diagnostic tests that can identify HIV-positive individuals who are at a high risk for developing clinical TB.  相似文献   
43.
The role played by dendritic cell (DC) subsets in the immune response to alloantigens is not well defined. In vitro experiments have extensively shown that freshly isolated myeloid (M)DCs induce a strong T lymphocyte proliferation whereas plasmacytoid (P)DCs do not, unless activated by CD40 ligation. The aim of these studies was to explore whether the interplay among PDCs, MDCs and T cells modulates alloresponse. Freshly isolated MDCs and PDCs were merged in different proportions and used as antigen presenting cells (APCs) in mixed lymphocyte cultures (MLC). As described, isolated PDCs only induced a mild alloresponse, while MDCs were potent inducers of alloproliferation. Unexpectedly, when PDCs were merged with even low numbers of MDCs (down to 100 cells) and used as APCs, a potent Th1 cell proliferation was detected. Survival and maturation of PDCs was increased in these MLC conditions, which could partially explain the magnitude of the T-cell response. Interestingly, the proportion of IFNgamma-producing cells generated in such cultures was higher compared to MDC-stimulated cultures. These data suggest that the interaction between both DC subsets is determinant to generate a potent Th1 response, at least in an allogeneic situation, and may be relevant to the outcome of allogeneic stem cell transplantation.  相似文献   
44.
Renal cell carcinomas may extend into the vena cava and the tumor thrombus occasionally involves the right atrium. The operative approach depends upon precise preoperative and intraoperative staging and thrombus localization. We report a case of renal cell carcinoma with complete inferior vena caval and hepatic vein occlusion with tumor extension into the right atrium. Preoperatively, transesophageal echocardiography provided superior images of the tumor and its extension, and intraoperatively allowed continuous monitoring of cardiac function and the removal of tumor from the atrium and inferior vena cava. Its use obviated the need for more costly and invasive preoperative and intraoperative procedures.  相似文献   
45.
46.
Congenital thoracic ectopic kidney is a very rare developmental anomaly and the rarest form of all ectopic kidneys. It is usually asymptomatic and discovered incidentally on routine chest radiography. Herein we reported the first case of staghorn stone in a thoracic kidney managed successfully by percutaneous nephrolithotomy.  相似文献   
47.
OBJECTIVES: We analyzed the methods and outcomes of urethroplasty in men with complex urethral disruptions. METHODS: The medical records of 40 men with complex urethral disruptions were analyzed. Surgical methods were individualized according to stricture location, severity and length of the stricture, bladder neck characteristics and presence of complicating factors. Patients were divided into four groups based on the above characteristics. RESULTS: End-to-end urethroplasty performed in six patients with short bulbar strictures (<3 cm) was successful in all. Elaborated perineal repair was performed in 10 patients with intermediate (3-6 cm) strictures with or without complicating factors. Elaborated perineal repair with urethral substitution was performed in nine patients with long segment stricture (>6 cm). Abdominal transpubic repair was successfully applied to patients with rectourethral fistula or lacerated bladder neck. Success rate of anastomotic urethroplasty was 95% while over all success rate was 85%. CONCLUSION: Guidelines for urethral reconstruction of complex urethral disruptions are predicated on stricture length, location, bladder neck characteristics and associated complicating factors. End-to-end urethroplasty with stricture excision is highly reliable for short strictures for which previous operative repair have failed. Elaborated perineal repair is extremely versatile for intermediate and longer strictures with associated complicating factors. Abdominal transpubic urethroplasty is effective for patients with rectourethral fistula or lacerated bladder neck.  相似文献   
48.
The objective of this study is to assess the results of repairing septal perforations with a vascularized pedicled alar cartilage island flap. Using the external rhinoplasty approach, a vascularized flap of alar cartilage, harvested as a cephalic trim and pedicled on the ascending columellar branches of the superior labial artery was raised. Bilateral mucoperichondrial septal flaps were elevated and the alar flap was transposed and secured within the defect and bilaterally overlaid with temporalis fascia. Silastic sheets were placed and remained in situ until the grafts were revascularized from the peripheries of the defect as well as centrally from the alar flap. The revascularized temporalis fascia acted as a scaffold for nasal remucosalization. The alar flap also increased the long-term structural robustness of the repair. Between 1999 and 2003, 14 patients with septal perforations ranging from 10 to 31 mm underwent septal reconstruction using this technique. There were nine males and five females. The flap was successfully raised in all cases and long-term closure was maintained in 12 patients (86%). The alar cartilage flap is an effective technique for repairing septal perforations in selected patients. It provides vascularized tissue which nourishes the grafts during remucosalization, and a cartilaginous framework, which affords long-term structural support to the repair. It also obviates the need to transpose nasal mucosa and create a secondary defect. The rhinoplasty approach furthermore permits additional nasal deformities to be corrected at the same time. Presented at the British Association of Plastic Surgeons Summer Scientific Meeting, Sheffield, UK (12 July 2006).  相似文献   
49.
50.
The purpose of investigation was to study the effect of intrathecal fentanyl on the onset and duration of hyperbaric bupivacaine-induced spinal block in adult male patients. Fortythree patients undergoing lower extremity or genitourinary surgery were enrolled to receive either 13.5 mg hyperbaric bupivacaine 0.75% + 0.5 ml CSF it, (Group I) or 13.5 mg hyperbaric bupivacaine 0.75% + 25 μg fentanyl it, (Group II) according to a randomized assessor-blind protocol. The onset and duration of sensory block were assessed by pinching the skin with forceps in the midclavicular line bilaterally every two minutes for first twenty minutes and then every five to ten minutes. Similarly, the onset and duration of motor block were assessed and graded at the same time intervals using the criteria described by Bromage. The time required for two sensory segment regression and sensory regression to L1 dermatome was 74 ± 18 and 110 ± 33 min vs 93 ± 22 and 141 ± 37 min in Groups I and II, respectively (P < 0.05). Intrathecal fentanyl did not enhance the onset of sensory or motor block, or prolong the duration of bupivacaine-induced motor spinal block. Fewer patients demanded pain relief in the fentanyl-treated group than in the control group in the early postoperative period (19% vs 59%; P < 0.05). Episodes of hypotension were more frequent in the fentanyl-treated group than in the control group (43% vs 14%; P < 0.05). We conclude that fentanyl, 25 μg it, prolonged the duration of bupivacaine-induced sensory block (sensory regression to L1 dermatone) by 28% and reduced the analgesic requirement in the early postoperative period following bupivacaine spinal block.  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