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   15804篇
  免费   1400篇
  国内免费   65篇
耳鼻咽喉   207篇
儿科学   354篇
妇产科学   231篇
基础医学   2054篇
口腔科学   220篇
临床医学   1745篇
内科学   3399篇
皮肤病学   380篇
神经病学   951篇
特种医学   658篇
外科学   2640篇
综合类   115篇
现状与发展   1篇
一般理论   5篇
预防医学   1332篇
眼科学   545篇
药学   1142篇
中国医学   85篇
肿瘤学   1205篇
  2024年   17篇
  2023年   186篇
  2022年   450篇
  2021年   847篇
  2020年   458篇
  2019年   562篇
  2018年   655篇
  2017年   431篇
  2016年   522篇
  2015年   526篇
  2014年   665篇
  2013年   718篇
  2012年   1145篇
  2011年   1111篇
  2010年   650篇
  2009年   525篇
  2008年   916篇
  2007年   895篇
  2006年   763篇
  2005年   715篇
  2004年   629篇
  2003年   548篇
  2002年   508篇
  2001年   500篇
  2000年   454篇
  1999年   375篇
  1998年   120篇
  1997年   102篇
  1996年   89篇
  1995年   75篇
  1994年   69篇
  1993年   59篇
  1992年   150篇
  1991年   105篇
  1990年   119篇
  1989年   112篇
  1988年   93篇
  1987年   80篇
  1986年   68篇
  1985年   59篇
  1984年   50篇
  1983年   32篇
  1982年   19篇
  1981年   11篇
  1980年   14篇
  1979年   15篇
  1978年   6篇
  1977年   10篇
  1976年   8篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Deng DY  Meng MV  Nguyen HT  Bellman GC  Stoller ML 《Urology》2002,60(3):415-9; discussion 419-20
  相似文献   
942.
Usual interstitial pneumonia: histologic study of biopsy and explant specimens   总被引:10,自引:0,他引:10  
The pathologic findings in biopsy and subsequent explant specimens from 20 patients with usual interstitial pneumonia (UIP) were reviewed to refine histologic criteria for diagnosis, to identify factors that may confound diagnosis, and to assess the relationship of UIP and nonspecific interstitial pneumonia (NSIP). One case of NSIP was also identified and included for comparison. Surgical biopsies from 15 of the 20 UIP cases were diagnosed as UIP, whereas 5 showed only nondiagnostic changes. An important new observation is that areas resembling nonspecific interstitial pneumonia (NSIP-like areas) are present in the majority of UIP cases in both biopsy and explant specimens, and they are extensive in some. Ten of the 15 UIP biopsies were considered straightforward, with typical patchy interstitial fibrosis, honeycomb change, and fibroblast foci. Five cases were considered difficult because of prominent NSIP-like areas in two, extensive honeycomb change in one, superimposed diffuse alveolar damage in one, and superimposed bronchiolitis obliterans-organizing pneumonia in one. The most helpful feature for diagnosing UIP in difficult cases was the presence of a distinct patchwork appearance to the characteristic uneven or variegated parenchymal involvement along with evidence of architectural derangement. No explant showing UIP was preceded by biopsy findings of NSIP, and the one NSIP case appeared similar at biopsy and explant. NSIP or NSIP-like areas and UIP may reflect different mechanisms of fibrosis related either to different severity of injury or to different injuries.  相似文献   
943.
944.
Our experience with tissue expansion on a series of 50 cases in Vietnam   总被引:1,自引:0,他引:1  
The authors reviewed their experience with tissue expansion from July of 1995 to December of 1999 at Hanoi Plastic Surgery Center. A total of 75 tissue expanders of various sizes were placed in 50 consecutive patients (16 men and 34 women) for the reconstruction of secondary defects (burn scars, skin graft scars, hypertrophic scars, keloids, capillary hemangioma, congenital nevi and micotia). The average age of patients was 21 years. The tissue expansion protocol was used in clinical as well as common principle. The main technical details are modified in this procedure by the authors: type of intralesional incision for expander insertion, closing of wound incision by three layers, evacuation of the liquid in the prosthesis pocket, injection with antibiotic solution and expanded flap capsulectomy. The complications rate was 10.6% (8 complications in 75 expanders). The most common complications consisted of infection, hematoma, exposure of valve, dehiscence of incision, necrosis of the distal expanded flap. The overall failure rate was 8%. Thus our modified surgical details allowed us to decrease the major complications and to achieve the best possible functional and aesthetic results.  相似文献   
945.
Cardiac function during laparoscopic vs open gastric bypass   总被引:2,自引:2,他引:0  
BACKGROUND: Hypercarbia and increased intraabdominal pressure during prolonged pneumoperitoneum can adversely affect cardiac function. This study compared the intraoperative hemodynamics of morbidly obese patients during laparoscopic and open gastric bypass (GBP). METHODS: Fifty-one patients with a body mass index (BMI) of 40-60 kg/m2 were randomly allocated to undergo laparoscopic (n = 25) or open (n = 26) GBP. Cardiac output (CO), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), heart rate (HR), and mean arterial pressure (MAP) were recorded at baseline, intraoperatively at 30-min intervals, and in the recovery room. Systemic vascular resistance (SVR) and stroke volume (SV) were also calculated. RESULTS: The two groups were similar in terms of age, weight, and BMI. Operative time was longer in the laparoscopic than in the open group (p < 0.05). The HR and MAP increased significantly from baseline intraoperatively, but there was no significant difference between the two groups. In the laparoscopic group, CO was unchanged after insufflation, but it increased by 5.3% at 2.5 h compared to baseline and by 43% compared to baseline in the recovery room. In contrast, during open GBP, CO increased significantly by 25% after surgical incision and remained elevated throughout the operation. CO was higher during open GBP than during laparoscopic GBP at 0.5 h and at 1 h after surgical incision (p < 0.05). During laparoscopic GBP, CVP, MPAP, and SVR increased transiently and PAWP remained unchanged. During open GBP, CVP, MPAP, and PAWP decreased transiently and SVR remained unchanged. There was no significant difference in the amount of intraoperative fluid administered during laparoscopic (5.5 +/- 1.6 L) and open (5.6 +/- 1.7 L) GBP. CONCLUSION: Prolonged pneumoperitoneum during laparoscopic gastric bypass does not impair cardiac function and is well tolerated by morbidly obese patients.  相似文献   
946.
PURPOSE: To assess anterior segment anatomy in uveitis-glaucoma- hyphema syndrome. DESIGN: Retrospective case series. METHODS: Nine pseudophakic eyes (nine patients) with complete or incomplete uveitis-glaucoma-hyphema syndrome underwent ultrasound biomicroscopy. RESULTS: Ultrasound biomicroscopy revealed intraocular lens malposition in each case. Of the eight eyes with posterior chamber intraocular lenses, haptics were in contact with the iris pigment epithelium (four eyes) or the pars plicata (three eyes) or prolapsed into the angle recess near a filtration bleb internal ostium (one eye). All other posterior chamber intraocular lens haptics were located in the ciliary sulcus with the exception of two in the capsular bag. Both haptics in the eye with the anterior chamber intraocular lens had eroded into the ciliary body. CONCLUSION: By its ability to detect haptic position, ultrasound biomicroscopy can assist in elucidating the cause of uveitis-glaucoma-hyphema syndrome and in deciding on the course of treatment.  相似文献   
947.
Nguyen VT  Park DJ  Levin L  Feldon SE 《Ophthalmology》2002,109(2):384-388
OBJECTIVE: To compare the success rates for strabismus surgery designed to correct limitation of duction with surgery designed to correct deviation in patients with Graves' ophthalmopathy. DESIGN: Retrospective nonrandomized comparative trial. PARTICIPANTS: One hundred thirty-seven patients with Graves' ophthalmopathy who had undergone at least one extraocular muscle surgery were divided into two groups: those whose first surgery occurred before June 1997 (control group) and those whose first surgery occurred in June 1997 or thereafter (case group). INTERVENTIONS: Extraocular muscle surgery primarily directed at either correcting deviation (control group) or correcting limitation of ductions (case group). MAIN OUTCOME MEASURES: Postoperative deviations in the primary position were measured in prism diopters 30 to 180 days after surgery. A postoperative deviation of less than 5 diopters was considered a successful surgical outcome. RESULTS: Patients undergoing strabismus surgery specifically designed to correct limitation of duction achieved a 74% success rate compared with a 44% success rate in the control group (P < 0.01). Furthermore, the rate of reoperation in this group was only 27% compared with 44% in the control group (P < 0.04). CONCLUSIONS: Compared with surgery aimed primarily at the correction of deviation, extraocular muscle surgery tailored to address restriction of ductions in patients with Graves' ophthalmopathy is associated with improved surgical success of initial realignment and with a lower rate of reoperation  相似文献   
948.
Nguyen TN  Polomeno RC  Farmer JP  Montes JL 《Ophthalmology》2002,109(3):520-4; discussion 524-5
OBJECTIVE: To present the ophthalmic features and visual prognosis of patients with slit-ventricle syndrome (SVS). DESIGN: Observational case series. PARTICIPANTS: Six patients diagnosed and treated with SVS at the Montreal Children's Hospital between 1985 and 1999. METHODS: Patients were included in this study if they had an appropriate ophthalmologic follow-up and if they fulfilled the criteria for the diagnosis of SVS based on intracranial pressure monitoring and neuroimaging studies. MAIN OUTCOME MEASURES: Features studied included patients' baseline ophthalmologic evaluation, visual outcome, and neurosurgical characteristics. RESULTS: The follow-up ranged from 1 to 14 years. The average number of shunting procedures was 3.7. Ocular examination performed on the initial visit revealed a normal visual acuity in four patients, esotropia in three of six patients, and nystagmus in two of six patients. Cycloplegic refraction was normal in all the subjects. Initial funduscopic evaluation revealed optic atrophy in a 4-month-old infant, whereas two children developed optic atrophy later in the course of the disease. One child developed severe visual field defects. The two children with optic atrophy had moderate to severe loss of visual acuity associated with SVS. CONCLUSIONS: A prompt recognition of patients with SVS is crucial, because these individuals are at an increased risk for significant visual loss.  相似文献   
949.
Automated perimetry: a report by the American Academy of Ophthalmology   总被引:10,自引:0,他引:10  
OBJECTIVE: The purpose of this document is to summarize and evaluate the effectiveness of new automated perimetry tests and algorithms in diagnosing glaucoma and detecting disease progression. METHODS: A literature search on automated perimetry retrieved over 300 citations from 1994 to 2001, of which 71 were selected as relevant to this assessment. The quality of the evidence obtained from these studies was assessed by the methodologist. RESULTS: The four automated perimetry techniques described in this assessment are short wavelength automated perimetry (SWAP), frequency doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and motion automated perimetry (MAP). The algorithms described are Swedish interactive threshold algorithm (SITA) and SITA fast. With the exception of SWAP, these techniques and algorithms reduce testing time and inconsistent patient performance when compared with conventional full threshold testing. CONCLUSIONS: Short wavelength automated perimetry detected visual field loss earlier than standard threshold automated perimetry, with a sensitivity and specificity of about 88% and 92% respectively. However, it is a lengthy, demanding test, is sensitive to media opacities, and has a greater magnitude of long-term fluctuation compared with standard threshold automated perimetry, which make it difficult to assess disease progression accurately. When compared to standard threshold automated perimetry, FDT perimetry showed sensitivity and specificity greater than 97% for detecting moderate and advanced glaucoma, and sensitivity of 85% and specificity of 90% for early glaucoma. As FDT perimetry has a short testing time and is resistant to blur and pupil size, it may be a useful screening tool. In a longitudinal study, high-pass resolution perimetry was more effective than standard threshold automated perimetry in monitoring progressive glaucomatous loss, detecting progression at a median of 12 months earlier in 54% of patients studied. Motion automated perimetry demonstrated usefulness in detecting early glaucomatous visual loss in a longitudinal study. Studies on SITA demonstrated greater sensitivity and reproducibility and less intertest variability when compared to standard full threshold testing and a 50% reduction in testing times. A study comparing standard full threshold, SITA, and SITA fast found a sensitivity of 95% for the first two techniques and 93% for SITA fast. Long-term follow-up studies are needed to assess the ability of these techniques to detect progression of glaucoma over time.  相似文献   
950.
Two years experience with the new accommodative 1 CU intraocular lens   总被引:3,自引:0,他引:3  
After marked improvement of optical rehabilitation of cataract patients during the last decades due to small incision surgery and foldable intraocular lenses (IOL), presbyopia is now one of the great unsolved questions in ophthalmology. During recent years a new accommodative IOL, the 1CU lens, has been developed based on the concepts of K.D. Hanna and on finite element computer simulation models. The 1CU IOL is designed to transform contracting forces of the ciliary muscle into anterior movement of the IOL optic (optic-shift concept). After the first implantation of a 1CU IOL in Erlangen in June 2000, we have now successfully implanted the 1CU IOL in over 90 patients. Our experiences and the results of several clinical studies indicate good and safe implantability, good centration, no IOL-specific complications, and good distance visual acuity. In comparison to control groups with conventional IOL, patients with the 1CU enjoyed significantly better distance-corrected near visual acuity, a larger accommodative range, and increased anterior and posterior axial movement of the lens optic after medical stimulation or inhibition of the ciliary muscle. We interpret our results as confirmation of the optic-shift concept of the 1CU IOL. Overall, the concept of accommodative IOL appears attractive and may have a great potential in the future. Additional studies including randomized blind multicenter evaluation of the 1CU IOL are necessary to further evaluate long-term and accommodative results.  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