全文获取类型
收费全文 | 7021篇 |
免费 | 424篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 170篇 |
妇产科学 | 94篇 |
基础医学 | 976篇 |
口腔科学 | 122篇 |
临床医学 | 556篇 |
内科学 | 1807篇 |
皮肤病学 | 312篇 |
神经病学 | 481篇 |
特种医学 | 265篇 |
外科学 | 838篇 |
综合类 | 24篇 |
预防医学 | 365篇 |
眼科学 | 179篇 |
药学 | 539篇 |
中国医学 | 12篇 |
肿瘤学 | 706篇 |
出版年
2023年 | 54篇 |
2022年 | 85篇 |
2021年 | 152篇 |
2020年 | 95篇 |
2019年 | 133篇 |
2018年 | 172篇 |
2017年 | 141篇 |
2016年 | 179篇 |
2015年 | 165篇 |
2014年 | 218篇 |
2013年 | 269篇 |
2012年 | 400篇 |
2011年 | 422篇 |
2010年 | 222篇 |
2009年 | 217篇 |
2008年 | 400篇 |
2007年 | 388篇 |
2006年 | 376篇 |
2005年 | 390篇 |
2004年 | 388篇 |
2003年 | 405篇 |
2002年 | 376篇 |
2001年 | 148篇 |
2000年 | 153篇 |
1999年 | 118篇 |
1998年 | 65篇 |
1997年 | 66篇 |
1996年 | 50篇 |
1995年 | 43篇 |
1994年 | 48篇 |
1993年 | 45篇 |
1992年 | 90篇 |
1991年 | 95篇 |
1990年 | 88篇 |
1989年 | 72篇 |
1988年 | 78篇 |
1987年 | 56篇 |
1986年 | 68篇 |
1985年 | 49篇 |
1984年 | 43篇 |
1983年 | 46篇 |
1982年 | 30篇 |
1979年 | 33篇 |
1977年 | 24篇 |
1974年 | 35篇 |
1973年 | 29篇 |
1972年 | 24篇 |
1971年 | 34篇 |
1970年 | 35篇 |
1969年 | 28篇 |
排序方式: 共有7484条查询结果,搜索用时 15 毫秒
71.
Magnesium has neuroprotective and antivasospastic properties in the presence of subarachnoid hemorrhage (SAH). The present
study investigated the effect of intracisternal administration of magnesium on cerebral vasospasm in the experimental SAH
rat model. The rat double-SAH model (0.2 mL autologous blood injected twice into the cisterna magna) was used. Normal saline
(SAH group, N = 8) or 10 mmol/L magnesium sulfate in normal saline (SAH + MG group, N = 8) was infused into the cisterna magna at 1.5 μL/min for 30 min on day 5. Control rats without SAH also received intracisternal
infusion of normal saline (control group, N = 6). Local cerebral blood flow (CBF) at 24 locations and the weighted average were quantitatively measured by the autoradiographic
technique using [14C]iodoantipyrine during infusion. The weighted average CBF was significantly reduced (P < 0.01, Student’s t-test) in the SAH group (0.78 ± 0.16 mL g−1 min−1) compared to the control group (1.0 ± 0.15 mL g−1 min−1) and was significantly improved (P < 0.01, Student’s t-test) in the SAH + MG group (0.98 ± 0.18 mL g−1 min−1). Local CBF was significantly reduced (P < 0.05, unpaired t test) in 16 locations in the SAH group and significantly improved (P < 0.05, unpaired t test) in 12 locations in the SAH + MG group. Intracisternal infusion of magnesium sulfate significantly improved reduced
CBF induced by experimental SAH in the rat. 相似文献
72.
73.
74.
Yoshinori Ishii Hideo Noguchi Mitsuhiro Takeda Junko Sato Yoshihiro Kishimoto Shin-Ichi Toyabe 《Journal of orthopaedic science》2013,18(5):727-732
Purpose
It is still controversial whether simultaneous or staged total knee arthroplasty (TKA) is most desirable for patients with bilateral knee osteoarthritis. We retrospectively evaluated changes in balance among patients with bilateral osteoarthritis who underwent staged TKA using a gravicorder.Methods
Patients were stratified into two groups: the unilateral group (UG) (22 patients) consisted of patients who did not undergo a second TKA within 24 months of the first TKA, and the bilateral group (BG) (20 patients) were those who had a second TKA within 12 months after initial TKA.Results
The mean gravity center position (GCP), which indicates the translation of GCP in the mediolateral direction between pre- and post-TKA shifted to the operative side in both groups after initial surgery. While the GCP was maintained on the same side in UG over 2 years follow-up, in BG it moved to the opposite side and approached a central position after the second TKA. Locus length of GCP (LG), which indicates postural control function by proprioceptive reflex showed significant improvement after initial TKA in UG, while BG showed significant improvement after the second TKA.Conclusions
The degree of LG improvement after initial TKA may indicate the necessity of a second TKA for patients with bilateral osteoarthritis. The current study suggests that simultaneous bilateral TKA is not always necessary for patients with bilateral knee arthritis, and that properly performed rehabilitation such as improving postural sway after initial TKA might attenuate the timing for the second TKA. 相似文献75.
Maruyama M Okamoto H Suwa J Asou T Hoka S 《Masui. The Japanese journal of anesthesiology》2004,53(6):629-633
BACKGROUND: We evaluated the changes in the bispectral index (BIS) as a potential indicator of level of consciousness in infants and children undergoing fast track cardiac surgery. METHODS: Twenty-one children undergoing fast track cardiac surgery were recruited into this study. Anesthesia was maintained with inhaled sevoflurane and intravenous fentanyl 10 microg x kg(-1). Cardiopulmonary bypass (CPB) with mild hypothermia and an immediate tracheal extubation protocol were used. BIS was recorded throughout the operation. RESULTS: In average, BIS was kept almost under 70 with 0.5-3.0% of sevoflurane. During rewarming from mild hypothermia, BIS increased temporarily over 70 in about a half of children. We, therefore, treated them by increasing sevoflurane concentration. Nineteen children were extubated in the operating room, and two patients were extubated in ICU within three hours after surgery. CONCLUSIONS: BIS was kept within the level of adequate sedation during surgery. However, since the increase in BIS during the rewarming phase could reflect light anesthesia, caution should be taken around this phase. 相似文献
76.
Matsuoka Y Ishimaru H Arai G Aida J Okada Y Ito Y 《Hinyokika kiyo. Acta urologica Japonica》2004,50(9):637-640
We report a case of invasive renal pelvic tumor with high serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9). An 86-year-old man presented with macrohematuria. Retrograde pyelography demonstrated a filling defect in right upper calyx, suspected of renal pelvic tumor. The levels of serum CEA and CA 19-9 were elevated to 28.0 ng/ml and 122 U/ml, respectively. No abnormalities were found in the gastrointestinal tract. Right nephroureterectomy was performed, and histopathological diagnosis was transitional cell carcinoma, grade 2>grade 3, accompanied with adenocarcinoma immuno-stained for CEA and CA19-9. A part of the tumor showed a tubular growth pattern. Both serum levels of CEA and CA 19-9 immediately decreased to the normal range after the operation, but increased again with lung and hepatic metastases. 相似文献
77.
J Matsuyama 《Neurologia medico-chirurgica》2012,52(8):563-569
Reliable prognostic parameters indicating progression in residual pituitary adenoma after surgery are necessary. The World Health Organization classification of tumors of endocrine organs defines atypical pituitary adenomas as tumor with Ki-67 labeling index higher than 3%, excessive p53 immunoreactivity, and increased pleomorphism. The real value of Ki-67 labeling index correlating with tumor progression is controversial. We investigated the relationship between positive labeling for MIB-1 and clinical features of 39 patients with pituitary adenomas with and without rapid re-growth after initial surgery. Ki-67 expression revealed pituitary adenomas with progression (re-growth within 5 years after initial surgery) had a mean proliferation index of 3.66 ± 3.00% (mean ± standard deviation [SD], n = 12), which was significantly higher than in tumors without progression of 1.89 ± 1.25% (mean ± SD, n = 27) (p < 0.05, Mann-Whitney test). Receiver operating characteristic analysis showed a threshold level of Ki-67 expression greater than 2.0% predicts progression with high specificity. Younger patients had higher MIB-1 index and more progression (p < 0.05). Adenomas with cavernous sinus invasion, functioning adenomas, and giant adenomas had higher MIB-1 index (p < 0.05). There was no significant correlation between tumor size or cavernous sinus invasion and progression. More completely removed tumors were less progressive. A threshold of 2% for the MIB-1 labeling index predicts higher risk of progression of residual adenomas after surgery, so shorter interval of follow-up neuroimaging, and early initiation of adjuvant therapy might be required. 相似文献
78.
Katsumi Takase Tsuyoshi Kumakura Ryohei Kono Kotaro Shinmura 《European journal of orthopaedic surgery & traumatology : orthopedie traumatologie》2012,22(7):555-560
Backgrounds
Generally, the surgical treatment for traumatic acromioclavicular joint dislocation is recommended for type 5 according to Rockwood’s classification. We believe that anatomical restoration of coracoclavicular ligament could best restore the function of the acromioclavicular joint. We attempted to correctly reconstruct the anatomy of the coracoclavicular ligament (trapezoid and conoid ligaments) in which the ipsilateral palmaris longus tendon and Endobutton were used as the reconstructing ligament and fixation material, respectively.Study designs
Cross-sectional study.Methods
The subjects were 16 patients (15 men and one woman). The mean age at the time of the surgery was 38.6?years. The mean time of the surgery from the injury was 16.3?days. The mean duration of postoperative follow-up was one?year and 5?months.Results
The reduction in the acromioclavicular joint was complete in 10 of 16 patients. Meanwhile, the subluxation that represented less than 5?mm superior translation of the clavicle, occurred only in 5, that represented 5–10?mm superior translation in none, and the complete dislocation occurred in one patient. Concerning the range of motion, mean forward flexion was 171°, mean abduction was 165°, mean internal rotation was Th11, and mean horizontal adduction was 132°. Pain, fatigues on the shoulder girdle, and impairments with shoulder motion on the affected side disappeared one?month after surgery.Conclusion
Although it requires excision of the ipsilateral palmaris longus for graft, we believe that anatomical restoration of both coracoclavicular ligaments could best restore the function of the acromioclavicular joint. 相似文献79.
Comparison of grey matter and metabolic reductions in frontotemporal dementia using FDG-PET and voxel-based morphometric MR studies 总被引:1,自引:0,他引:1
Kanda T Ishii K Uemura T Miyamoto N Yoshikawa T Kono AK Mori E 《European journal of nuclear medicine and molecular imaging》2008,35(12):2227-2234
Purpose The aim of this study was to investigate the regional differences between the morphologic and functional changes in the same
patients with frontotemporal dementia (FTD) using statistical parametric mapping and voxel-based morphometry (VBM).
Methods Thirteen FTD patients (mean age, 64.9 years old; mean MMSE score, 17.7), 20 sex-matched Alzheimer’s disease (AD) patients
(mean age, 65.0 years old; mean MMSE score, 17.5), and 20 normal volunteers (mean age, 65.2 years old; mean MMSE score, 29.0)
underwent both [18F]FDG positron emission tomography and three-dimensional spoiled gradient echo MRI. Statistical parametric mapping was used
to conduct a VBM analysis of the morphologic data, which were compared voxel by voxel with the results of a similar analysis
of glucose metabolic data.
Results FTD patients showed decreased grey matter volume and decreased glucose metabolism in the frontal lobe and anterior temporal
lobe. In addition, there was a clear asymmetry in grey matter volume in FTD patients by the VBM analysis while the glucose
metabolic data showed little asymmetry. In AD patients, glucose metabolic reduction occurred in the bilateral posterior cingulate
gyri and parietal lobules while grey matter density decreased the least in the same patients.
Conclusion In FTD, metabolic and morphologic changes occur in the bilateral frontal lobe and temporal lobe with a limited asymmetry whereas
there was considerable discordance in the AD group. 相似文献
80.
Kono S Nishimura K Nishina T Yuasa S Ueyama K Hamada C Akamatsu T Komeda M 《The Journal of thoracic and cardiovascular surgery》2003,125(2):353-360
OBJECTIVES: The purpose of this study was to investigate how the inflow cannulation site of the left ventricular assist system with a centrifugal pump would influence cardiac function on failing heart models. METHODS: In 10 sheep, a left ventricular assist system was instituted by an outflow cannula in the descending aorta, two inflow cannulas in the left atrium and the left ventricle, and connecting those cannulas to a magnetically suspended centrifugal pump. A conductance catheter and a tipped micromanometer for monitoring the pressure-volume loop were also inserted into the left ventricle. Myocardial oxygen consumption was directly measured. Heart failure was induced by injection of microspheres into the left main coronary artery. The assist rate was varied from 0% to 100% at each inflow cannulation site. RESULTS: The pump flow with left ventricular cannulation increased during the systolic phase and decreased during the diastolic phase, whereas it was constant with left atrial cannulation. Ejection fraction with left atrial cannulation decreased as the assist rate increased, whereas that with left ventricular cannulation was maintained up to 75% assist. The external work with left atrial cannulation decreased gradually as the assist rate increased, whereas the external work with left ventricular cannulation did not decrease until the assist rate reached 75%. The myocardial oxygen consumption in both cannulations decreased proportionally as the assist rate increased; they were significantly less with left ventricular cannulation at the 100% assist rate than with left atrial cannulation. CONCLUSION: Left ventricular cannulation during left ventricular assistance maintains ejection fraction and effectively reduces oxygen consumption. 相似文献