全文获取类型
收费全文 | 14120篇 |
免费 | 661篇 |
国内免费 | 118篇 |
专业分类
耳鼻咽喉 | 340篇 |
儿科学 | 737篇 |
妇产科学 | 605篇 |
基础医学 | 995篇 |
口腔科学 | 465篇 |
临床医学 | 1136篇 |
内科学 | 3564篇 |
皮肤病学 | 226篇 |
神经病学 | 818篇 |
特种医学 | 597篇 |
外科学 | 3347篇 |
综合类 | 190篇 |
一般理论 | 2篇 |
预防医学 | 324篇 |
眼科学 | 500篇 |
药学 | 514篇 |
中国医学 | 26篇 |
肿瘤学 | 513篇 |
出版年
2024年 | 11篇 |
2023年 | 119篇 |
2022年 | 228篇 |
2021年 | 409篇 |
2020年 | 260篇 |
2019年 | 333篇 |
2018年 | 402篇 |
2017年 | 329篇 |
2016年 | 558篇 |
2015年 | 641篇 |
2014年 | 711篇 |
2013年 | 871篇 |
2012年 | 1126篇 |
2011年 | 1013篇 |
2010年 | 637篇 |
2009年 | 551篇 |
2008年 | 944篇 |
2007年 | 1094篇 |
2006年 | 1003篇 |
2005年 | 981篇 |
2004年 | 895篇 |
2003年 | 660篇 |
2002年 | 604篇 |
2001年 | 96篇 |
2000年 | 59篇 |
1999年 | 60篇 |
1998年 | 61篇 |
1997年 | 48篇 |
1996年 | 38篇 |
1995年 | 36篇 |
1994年 | 21篇 |
1993年 | 14篇 |
1992年 | 15篇 |
1991年 | 11篇 |
1990年 | 15篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1908年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Which patient, which pump? 总被引:1,自引:0,他引:1
102.
Changes in vascularity of cartilage endplate of degenerated intervertebral discs in response to melatonin administration in rats 总被引:3,自引:0,他引:3
We carried out an experimental investigation of cartilage endplate vascularity of degenerated intervertebral discs produced
by exogenous melatonin (MEL) treatment. Adult Swiss albino rats were divided into three groups: control, operated degeneration,
and MEL treatment. There were five rats in each group and, using a posterior approach, cuts were made parallel to the endplates
in the posterior annulus fibrosus in five consecutive intervertebral discs between the 5th and 10th vertebral segments of
the rats' tails. At 8 weeks, five of these animals were treated with exogenous MEL (s.c. injection of 30 μg/100 g body weight
daily for 4 weeks). In each experimental group, one animal was examined using CT scanner to study the density of the cartilage
endplate of the disc. To evaluate the bone growth and vascularity of the cartilage endplate region, the animals were killed
for subsequent histopathological evaluation. We found that the vascular channel counts and percentage areas from animals treated
with MEL were significantly lower than from the operated degeneration animals. Accordingly, the density histogram in the MEL
group showed a spike profile for both the vertebral body and the cartilage endplate, indicating an increase in the amount
of higher density tissues in these regions. Our results demonstrate that the use of MEL reduces the cartilage endplate vascularity
of degenerated intervertebral discs, suggesting that it may have an osteoinductive effect on bone formation. Further studies
are needed to characterize fully the relevance of our findings for the treatment of disorders such as postmenopausal osteoporosis. 相似文献
103.
Influence of number of pregnancies on bone mineral density in postmenopausal women of different age groups 总被引:7,自引:0,他引:7
Gur A Nas K Cevik R Sarac AJ Ataoglu S Karakoc M 《Journal of bone and mineral metabolism》2003,21(4):234-241
As data on the relationship between parity and bone mineral density often seem to be controversial, ultimately, a comprehensive
research study was thought to be necessary. This study focused on examining the influence of the number of pregnancies on
bone mineral density and investigating the relationship between pregnancy and bone mineral density at four sites in postmenopausal
women of different age groups. A total of 509 postmenopausal women, varying from 45 to 86 years of age (mean age of 60.85
± 7.53 years) were considered for the study. A standardized interview was employed to obtain information on demographics,
lifestyle, and, reproductive and menstrual histories. Patients were separated into four groups according to the number of
pregnancies, i.e., nulliparae (52 patients), one to two parity (66 patients), three to five parity (178 patients), and more
than five parity (213 patients). The patients were further classified into two age groups, 40–59 years (233 patients) and
60–80 years (276 patients), respectively. The number of pregnancies was found to range from 0 to 17 (with an overall mean
of 5.42 ± 3.68), with 4.29 ± 2.74 (range, 0–16) accounting for live births, while 1.02 ± 1.53 (range, 0–14) were abortions.
There were no significant differences among the groups with respect to parameters such as, age, body mass index (BMI), age
at menarche, age at menopause, and years since menopause (P > 0.05) in all of the 509 women and in the 40- to 59- and 60- to 80-year groups. When all the patients were considered, the
bone mineral density (BMD) values of the spine and the trochanter for the more-than-five-parity group, were found to be significantly
lower than those of the other groups (P < 0.05), while the BMD values of the spine and the femur (neck, trochanter) appeared to decrease with increasing parity.
In the 40- to 59-year group, the BMD of the spine in both the nulliparae and one-to-two-parity groups was significantly higher
than that of the more-than-five-parity group (P < 0.05). No significant differences were found among the groups with respect to the BMD values at any femur sites. The nulliparae
patients in the 60- to 80-year group exhibited significantly higher trochanter and Ward's BMD values than those of the more-than-five-parity
group (P < 0.05), whereas in the one-to-two-parity group, spine BMD values appeared to be significantly higher than those of the more-than-five-parity
group (p < 0.05). Significant correlations were found between the number of pregnancies and BMD values for the spine (r = −0.23; P < 0.01), trochanter (r = −0.16; P < 0.01), and Ward's triangle (r = −0.14; P < 0.05), with no significant correlation for femur neck BMD (r = −0.08; P > 0.05) values. In conclusion, the present study suggests that the number of pregnancies has an effect on the BMD values
and that this situation shows a variation in different age groups. In addition, our study indicates that there is a significant
correlation between the number of pregnancies and the spine, trochanter, and Ward's triangle BMD, but there is no correlation
for the femur neck BMD.
Received: April 30, 2002 / Accepted: January 16, 2003
RID="*"
ID="*" Offprint requests to: A. Gur 相似文献
104.
In hips with acetabular dysplasia, we performed Kotz osteotomy (group 1) in 22 hips (20 patients; mean age 24.3 years) and Ganz osteotomy (group 2) in 23 hips (22 patients; mean age 23.1 years). Group 1 was followed 83.3 (56-112) months and group 2 40.9 (24-66) months. In group 1, Harris hip score improved from average 74.9 to 86.9, mean center edge (CE) angle from -4.5 degrees to 30.3 degrees, and mean vertical center edge (VCE) angle from 5.3 degrees to 36.2 degrees. In group 2, Harris hip score improved from average 76.6 to 91.1, mean CE angle from -5.9 degrees to 32.0 degrees, and mean VCE angle from 5.0 degrees to 41.3 degrees. Using Pauwels criteria, regression was observed in 12 hips in group 1 and one progressed. In group 2, 15 hips showed regression and three progressed. In patients treated with Ganz osteotomy, the complication rate was higher and the complications more serious than in patients treated with Kotz osteotomy. Most complications were, however, seen among the first ten patients treated with Ganz osteotomy. Although we detected no significant difference between the two groups in terms of clinical and radiological findings, we believe the outcome to be slightly better after a properly performed Ganz osteotomy. 相似文献
105.
Ilkay Koray Bayrak Zafer Ozmen Mehmet Selim Nural Murat Danaci Baris Diren 《Korean journal of radiology》2008,9(3):250-257
OBJECTIVE: It has been advocated that a reduced injection volume with highly concentrated (1 M) contrast material can produce a sharper bolus peak and an increased intravascular first-pass gadolinium concentration when compared with the use of a lower concentration (0.5 M). A higher concentration would also cause a reduction in dose. The purpose of our study was to test the use of a low dose (0.05 mmol/kg) of gadobutrol in magnetic resonance renography and angiography and compare the findings with a dose of 0.1 mmol/kg. MATERIALS AND METHODS: One-hundred-thirty-four patients referred for magnetic resonance angiography for suspected renovascular disease participated in the study. Contrast enhanced MR renography and angiography were performed after administration of a bolus of 0.1 mmol/kg or 0.05 mmol/kg gadobutrol in randomized patients. The relative signal intensity-time curves of the aorta, peripheral cortex and parenchyma, were obtained. Two radiologists evaluated the angiographic images and evaluated the quality of angiography. RESULTS: The signal intensity with a low dose of gadobutrol was significantly lower in early phases, in the peripheral cortex (for 36, 54, 72 and 90 seconds), the parenchyma (for 36, 54, 72 seconds) and the aorta (for 18, 36, 54, 72 seconds). The decreases in the early phase obtained with a low dose of gadobutrol caused blunter time intensity curves. The difference in the quality scores of the readers for the angiographic images for the use of the two different doses was not statistically significant (p > 0.05). CONCLUSION: A lower dose of gadobutrol can be used for MR renal angiography, but for MR renography the normal dose should be used. 相似文献
106.
Jacobsen C Schön CA Kneubuehl B Thali MJ Aghayev E 《Journal of Forensic and Legal Medicine》2008,15(7):462-466
Accidental or intentional falls from a height are a form of blunt trauma and occur frequently in forensic medicine. Reports describing elevator accidents as a small subcategory of falls from heights are rare in the medical literature and no report on injury patterns or scene reconstruction of such an accident was found. A case of an accident in a hydraulic elevator with a man falling 3m was examined using post-mortem multi-slice computed tomography (MSCT) and autopsy. The man suffered an unusually extensive trauma and died at the scene. Post-mortem MSCT examination showed a comminute fracture of the skull, the right femur and the first lumbar vertebra. Severe lacerations of the brain with epidural, subdural and subarachnoidal haemorrhages over both hemispheres were diagnosed. Autopsy confirmed these findings. To reconstruct the accident we used radiological and autopsy results as well as findings at the scene. 相似文献
107.
Management of stiff hypertrophic nonunions by distraction osteogenesis: a report of 16 cases 总被引:2,自引:0,他引:2
Kocaoğlu M Eralp L Sen C Cakmak M Dincyürek H Göksan SB 《Journal of orthopaedic trauma》2003,17(8):543-548
OBJECTIVE: Hypertrophic nonunions can be managed successfully with distraction. Hypertrophic changes indicate that the tissue at the nonunion site has a biologic healing potential. The missing component is an appropriate mechanical environment to transform a hypertrophic nonunion into solid bone. DESIGN: At our institution, the records of 10 male and 6 female patients treated for stiff hypertrophic nonunion with the Ilizarov distraction method were retrospectively analyzed. The average age of the patients was 42.3 years (range 15-69 years). The nonunion time ranged from 8-48 months. All patients had at least 1 cm shortening, 3 patients had a deformity in one plane, and 13 had a deformity in two planes. The pathology was localized to the upper extremity in 5 patients, to the lower extremity in 11 patients, with a periarticular localization in 11 patients. An Ilizarov-type circular external fixator was applied in all patients to correct shortening, to correct deformity, and to achieve a solid union. RESULTS: All nonunions healed at an average follow-up of 38.1 months (range 24-95 months). The average time spent in the external fixator was 7.1 months (range 5-10 months). The average preoperative length discrepancy was 2.25 cm (range 1-8 cm), which was eliminated in all patients at the time of frame removal. The average coronal plane angulation of 19.7 degrees (range 15-37 degrees) and sagittal plane angulation of 20.8 degrees (range 5-45 degrees), together with translation in one patient, also were corrected to normal anatomic alignment. Complications included minor pin tract infections and hardware problems; recurrence of deformity was observed in one patient who refused to wear a protective brace after frame removal. CONCLUSIONS: Hypertrophic nonunions can be managed successfully with distraction. The Ilizarov device can address every aspect of a stiff hypertrophic nonunion, including shortening and deformity. 相似文献
108.
Erdem AF Yoruk O Alici HA Cesur M Atalay C Altas E Kursad H Yuksek MS 《Paediatric anaesthesia》2008,18(9):878-883
Background: Postoperative vomiting (POV) is a common complication after tonsillectomy. Dexamethasone is known to decrease postsurgical vomiting. In this study, we compared the effects of dexamethasone alone to dexamethasone plus propofol on postoperative vomiting in children undergoing tonsillectomy. Methods: In a randomized double‐blinded study, we evaluated 80 healthy children, aged 4–12 years, who underwent tonsillectomy with or without adenoidectomy. After anesthesia was induced by inhalation of sevoflurane, 0.15 mg·kg?1 dexamethasone and 2 μg·kg?1 fentanyl was administered i.v. to all patients. The patients in the dexamethasone plus propofol group received 1 mg·kg?1 propofol before intubation and continuously after intubation at a rate of 20 μg·kg?1·min?1 until the surgery was completed. Data for postoperative vomiting were grouped into the following time periods: 0–4 and 4–24 h. Data were analyzed using a Student’s t‐test and chi‐squared analysis. Results: The percentage of patients exhibiting a complete response (defined as no retching or vomiting for 24 h) increased from 37.5% in the dexamethasone‐alone group to 75% in the dexamethasone plus propofol group (P = 0.001). Twenty‐two patients (55%) in the dexamethasone‐alone and nine patients (22.5%) in the dexamethasone plus propofol groups experienced vomited during 0–4 h (P = 0.003). Eight patients in the dexamethasone‐alone group and three patients in the dexamethasone plus propofol group received ondansetron as a rescue antiemetic during the postoperative period. Conclusion: For children undergoing tonsillectomy, intraoperative subhypnotic propofol infusion combined with dexamethasone treatment provides a better prophylaxis against postoperative vomiting than does dexamethasone alone. 相似文献
109.
110.
Spontaneous rupture of the Achilles tendons in hemodialysis patients is a rare complication. The majority of these patients
have additional predisposing factors, such as previous use of fluoroquinolone antibiotics or corticosteroids. Spontaneous
rupture of bilateral Achilles tendons without any of those predisposing factors is exceptional. In this paper, we report a
43-year-old woman who had been undergoing regular hemodialysis for 16 years. She developed bilateral spontaneous and simultaneous
rupture of the Achilles tendons. She also developed pathological fracture of right femur neck 3 years later. Based on previous
cases of tendon ruptures in uremic patients and the lack of history for the use of corticosteroids or fluoroquinolones, we
believe that secondary hyperparathyroidism is the predisposing factor in this patient. 相似文献