全文获取类型
收费全文 | 148922篇 |
免费 | 7540篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 2450篇 |
儿科学 | 5067篇 |
妇产科学 | 3479篇 |
基础医学 | 22790篇 |
口腔科学 | 4723篇 |
临床医学 | 12241篇 |
内科学 | 26880篇 |
皮肤病学 | 4229篇 |
神经病学 | 15216篇 |
特种医学 | 6468篇 |
外国民族医学 | 31篇 |
外科学 | 22738篇 |
综合类 | 656篇 |
一般理论 | 40篇 |
预防医学 | 8052篇 |
眼科学 | 3252篇 |
药学 | 10207篇 |
中国医学 | 260篇 |
肿瘤学 | 7800篇 |
出版年
2023年 | 817篇 |
2022年 | 567篇 |
2021年 | 1357篇 |
2020年 | 1239篇 |
2019年 | 1503篇 |
2018年 | 3069篇 |
2017年 | 2618篇 |
2016年 | 3387篇 |
2015年 | 2996篇 |
2014年 | 3306篇 |
2013年 | 5772篇 |
2012年 | 7457篇 |
2011年 | 8344篇 |
2010年 | 4773篇 |
2009年 | 3288篇 |
2008年 | 8429篇 |
2007年 | 8846篇 |
2006年 | 8558篇 |
2005年 | 8481篇 |
2004年 | 7995篇 |
2003年 | 8031篇 |
2002年 | 7972篇 |
2001年 | 5588篇 |
2000年 | 7009篇 |
1999年 | 4054篇 |
1998年 | 1600篇 |
1997年 | 1297篇 |
1996年 | 1044篇 |
1995年 | 848篇 |
1994年 | 840篇 |
1993年 | 797篇 |
1992年 | 943篇 |
1991年 | 854篇 |
1990年 | 824篇 |
1989年 | 825篇 |
1988年 | 708篇 |
1987年 | 750篇 |
1986年 | 647篇 |
1985年 | 862篇 |
1984年 | 812篇 |
1983年 | 675篇 |
1982年 | 665篇 |
1981年 | 633篇 |
1980年 | 600篇 |
1979年 | 624篇 |
1978年 | 527篇 |
1977年 | 570篇 |
1976年 | 469篇 |
1975年 | 523篇 |
1974年 | 485篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Dietmar Georg PhD Bernhard Kroupa Petra Georg Peter Winkler Joachim Bogner Karin Dieckmann Richard Pötter 《Strahlentherapie und Onkologie》2006,182(8):473-480
PURPOSE: To compare commercial treatment-planning systems (TPS) for inverse planning (IP) and to assess constraint variations for specific IMRT indications. MATERIAL AND METHODS: For IP, OTP, XiO and BrainSCAN were used and step-and-shoot intensity-modulated radiotherapy (IMRT) delivery was assumed. Based on identical constraints, IP was performed for a prostate, head and neck, brain, and gynecologic case. IMRT plans were compared in terms of conformity/homogeneity, dose-volume histograms (DVHs), and delivery efficiency. For ten patients each of a class of indications, constraint variations were evaluated. RESULTS: IMRT plans were comparable concerning minimum target dose, homogeneity, conformity, and maximum doses to organs at risk. Larger differences were seen in dose gradients outside the target, monitor units, and segment number. Using help structures proved efficient to shape isodoses and to reduce segmentation workload. For IMRT class solutions, IP constraint variations depended on anatomic site. CONCLUSION: IP systems requiring doses as input and having objective functions based on physical parameters had a very similar performance. Constraint templates can be established for a class of IMRT indications. 相似文献
92.
93.
94.
Walter S Speidl Markus Exner Jasmin Amighi Wolfgang Mlekusch Schila Sabeti Stefan P Kastl Gerlinde Zorn Gerald Maurer Oswald Wagner Kurt Huber Erich Minar Johann Wojta Martin Schillinger 《Journal of endovascular therapy》2007,14(1):62-69
PURPOSE: To investigate whether balloon angioplasty of the superficial femoral artery (SFA) increases serum levels of C5a and whether C5a predicts risk of restenosis. METHODS: C5a antigen was measured at baseline and 8 hours after intervention in 131 consecutive patients (76 women; median age 72 years) with intermittent claudication who underwent successful primary SFA balloon angioplasty. Patients were followed for a median 10 months [interquartile range (IQR) 6 to 14] for the occurrence of >50% restenosis by duplex ultrasound. RESULTS: Median C5a levels increased significantly from 39.7 ng/mL (IQR 27.8 to 55.0) at baseline to 53.8 ng/mL (IQR 35.6 to 85.1, p<0.001) 8 hours post intervention. During the follow-up period, 70 (53%) patients developed restenosis. Increasing levels of C5a (quartiles) at baseline were significantly associated with an increased risk for restenosis (p=0.0092). Adjusted hazard ratios (95% confidence intervals) for restenosis with increasing quartiles of baseline serum C5a levels were 1.24 (0.60 to 2.58), 1.93 (0.95 to 3.93), and 2.08 (1.02 to 4.21), respectively, compared to the lowest quartile. This effect was independent of nonspecific inflammation as reflected by plasma levels of C-reactive protein. CONCLUSION: Inflammatory mechanisms play a major role in the development of restenosis after angioplasty. The complement component C5a exerts strong chemotactic and proinflammatory effects. Enhanced complement activation prior to PTA, as measured by higher levels of C5a, was significantly associated with restenosis after SFA balloon angioplasty. Pathways of complement inhibition thus may be worth investigating with respect to improving patency rates. 相似文献
95.
Gastric cancer still represents the second most common cause of gastrointestinal cancers in Germany. A disturbing issue is that at the time of diagnosis there are less than 15% of patients for whom a cure can be achieved. Nowadays, biological, histomorphological, molecular genetic and epidemiological data suggest that Helicobacter pylori eradication may lead to the prevention of gastric pre-neoplastic lesions and even gastric cancer. At present, eradication can be offered to selected patients and populations at increased risk, but more research is required before embarking on general and global H. pylori eradication for gastric cancer prevention. The main challenge is to determine how long mucosal abnormalities remain reversible and gastric cancer development can be halted. 相似文献
96.
Birgitta Malmberg Göran Kecklund Björn Karlson Roger Persson Per Flisberg Palle Ørbaek 《BMC health services research》2010,10(1):239
Background
It is well known that physicians' night-call duty may cause impaired performance and adverse effects on subjective health, but there is limited knowledge about effects on sleep duration and recovery time. In recent years occupational stress and impaired well-being among anaesthesiologists have been frequently reported for in the scientific literature. Given their main focus on handling patients with life-threatening conditions, when on call, one might expect sleep and recovery to be negatively affected by work, especially in this specialist group. The aim of the present study was to examine whether a 16-hour night-call schedule allowed for sufficient recovery in anaesthesiologists compared with other physician specialists handling less life-threatening conditions, when on call. 相似文献97.
BACKGROUND: Necrotizing fasciitis (NF) is still a source of high morbidity and mortality. These difficult cases are increasingly referred to burn centers due to special wound and critical care issues. Here we examine our institution's recent experience with a large series of NF. METHOD: We performed a retrospective chart review of 32 consecutive patients over a 10-year period with NF who required radical surgical debridement and surface reconstruction. RESULTS: Overall survival was 85%, with average length of stay of 74.0+/-7.5 days for survivors (S) and 68.8+/-6.3 days for nonsurvivors (NS) (P>0.05). Time until first operation was 5.2 days in S and 3.4 days in NS (P<0.05). Patient age averaged 51.1+/-11.2 years for S and 57.0+/-12.0 years for NS (P<0.05). Survivors averaged 1.6 relevant comorbidities and NS averaged 3.6 (P<0.05). Affected total body surface (TBS) per patient averaged 6.8+/-3.3% for S and 10.2+/-5.1% for NS (P<0.05). All NS had affection of the trunk, and none of the patients with exclusive affection of extremities died. CONCLUSIONS: There were frequent delays in diagnosis and referrals to our institution, and progress can be made in educating the medical community to identify these patients. Not only the affected TBS and location but also comorbidities, age, and immediate surgical treatment are important prognostic factors. Referral to a specialized facility such as a burn center is urgently recommended for optimal surgical intervention, wound care, and critical care management. 相似文献
98.
Levente Gáspár Zoltán Jónás László Kiss György Vereb Zoltán Csernátony 《European journal of orthopaedic surgery & traumatology : orthopedie traumatologie》2009,19(6):403-407
Background Coccygodynia can cause severe pain and disability in patients. There are contradictions in the literature regarding the final
results of coccygectomy for coccygodynia. We evaluated the long-term effects of coccygectomy on the intensity, characteristics,
and manifestation of pain caused by coccygodynia to determine the adequacy of operation among treatment modalities.
Materials and methods Thirty-four patients with coccygodynia were treated by coccygectomy. In 22 cases, trauma, and in one case childbirth was the
cause. 11 cases were regarded as idiopathic. The intensity, characteristics of pain, and the most painful activities were
evaluated at an average of 7.6 (3–18) years of follow-up time.
Results Before the operation, all 34 patients had pain while sitting, moreover, 26 of them had pain during standing, walking, at night
or a combination of these. 21 patients had intolerable or very intensive, mainly acute, sharp or burning pain. 11 patients
had dyschesia, 2 had dysuria and 6 had dyspareunia. At follow-up, 7 patients were completely free of pain, 15 others had moderate,
11 medium, and only one patient had severe, but none had intolerable pain. Only seven patients had acute, sharp or burning
pain postoperatively. The decrease of average pain score from 8.0 to 3.2 was significant (P < 10−12). The number of the patients with dyschesia and dyspareunia decreased from 11 to 7 and from 6 to 3, respectively. Two patients
had dysuria, but their complaints did not change after the operation. One of the two patients who needed reoperation had an
excellent final result, while the other remained unchanged. 12 and 16 patients (together 82%) regarded the final result of
the operation excellent and good, respectively. The condition of five others did not change, while one became worse. The patients
with younger age, smaller body mass index, and less co-morbidities had better final result. There were no serious complications.
Conclusion Coccygectomy for coccygodynia is a safe method to decrease the intensity of pain and other complaints of the patients. The
operation can be the choice of treatment if conservative measures fail. 相似文献
99.
Murat Hamit Aytar Fikret Doğulu Berker Cemil Ertan Ergün Gökhan Kurt Kemali Baykaner 《Child's nervous system》2007,23(6):719-721
Introduction Iniencephaly, a neural tube defect involving occiput and inion and combined with rachischisis of the cervical, thoracic spine,
and retroflexion position of the head is a very rare congenital abnormality of the fetus–newborn with a 0.1–10 of 10,000 prevalence.
This abnormality’s prognosis is thought to be dismal. This abnormality can be associated with other abnormalities such as
anencephaly, encephalocele, hydrocephalus, cyclopia, absence of the mandible, cleft lip and palate, cardiovascular disorders,
diaphragmatic hernia, renal abnormalities, overgrowth of the arms compared to the legs, and club food and gastrointestinal
atresia.
Discussion Most of the patients are dead born, and the others die in a few hours. There are only six previously documented long-term
survivors. In our case, our patient with iniencephalic signs and findings is still living. She is 2 years old now. We think
that this patient presents a mild form of iniencephaly. 相似文献
100.