全文获取类型
收费全文 | 11743篇 |
免费 | 592篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 85篇 |
儿科学 | 152篇 |
妇产科学 | 234篇 |
基础医学 | 1358篇 |
口腔科学 | 261篇 |
临床医学 | 788篇 |
内科学 | 2878篇 |
皮肤病学 | 195篇 |
神经病学 | 794篇 |
特种医学 | 515篇 |
外科学 | 2126篇 |
综合类 | 33篇 |
预防医学 | 297篇 |
眼科学 | 152篇 |
药学 | 959篇 |
中国医学 | 29篇 |
肿瘤学 | 1529篇 |
出版年
2023年 | 50篇 |
2022年 | 116篇 |
2021年 | 195篇 |
2020年 | 120篇 |
2019年 | 153篇 |
2018年 | 169篇 |
2017年 | 158篇 |
2016年 | 209篇 |
2015年 | 200篇 |
2014年 | 250篇 |
2013年 | 343篇 |
2012年 | 474篇 |
2011年 | 551篇 |
2010年 | 296篇 |
2009年 | 274篇 |
2008年 | 541篇 |
2007年 | 528篇 |
2006年 | 526篇 |
2005年 | 497篇 |
2004年 | 614篇 |
2003年 | 588篇 |
2002年 | 554篇 |
2001年 | 456篇 |
2000年 | 460篇 |
1999年 | 445篇 |
1998年 | 160篇 |
1997年 | 120篇 |
1996年 | 113篇 |
1995年 | 111篇 |
1994年 | 83篇 |
1993年 | 65篇 |
1992年 | 264篇 |
1991年 | 204篇 |
1990年 | 232篇 |
1989年 | 268篇 |
1988年 | 259篇 |
1987年 | 244篇 |
1986年 | 214篇 |
1985年 | 216篇 |
1984年 | 125篇 |
1983年 | 114篇 |
1982年 | 48篇 |
1979年 | 105篇 |
1978年 | 66篇 |
1977年 | 47篇 |
1974年 | 43篇 |
1972年 | 51篇 |
1971年 | 53篇 |
1970年 | 48篇 |
1969年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The authors performed a serial study of a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like syndrome (MELAS) who presented with diffusion-weighted MRI (DWI). DWI demonstrated a higher apparent diffusion coefficient in the lesion than in the control region during the acute stage of stroke. Vasogenic edema is present in stroke-like episodes in MELAS. 相似文献
102.
103.
Nakano N Hatakeyama Y Fukatsu R Hayashi S Fujii M Fujimori K Takahata N 《Progress in neuro-psychopharmacology & biological psychiatry》1999,23(6):1053-1062
1. Three patients with Alzheimer's disease (AD) and three healthy controls (HC) were examined for eye-head coordination. Regional cerebral blood flow (rCBF) was measured in AD patients. 2. Eye-head coordination was analyzed using a Vision analyzer, and magnetic sensors. The authors measured the rCBF with 123I-IMP, and 99mTc-ECD SPECT. 3. AD reduced gaze accuracy and head movements, and prolonged the latency of saccade as compared to HC. AD patients had a tendency to focus on the target by using eye movements only. 4. AD reduced the rCBF in the inferior parietal part and the visual area, relative to the motor area. Damage of these areas may have caused the eye-head coordination disorders in the AD patients. 相似文献
104.
The authors report a 3-year-old male with glutaric aciduria type II, whose magnetic resonance imaging studies revealed agenesis of the cerebellar vermis and hypoplastic temporal lobes. Proton magnetic resonance spectroscopy in the parietal white matter revealed a markedly increased choline/creatine ratio, suggesting a demyelinating process. Gas chromatographic analysis of urinary organic acids should be studied in any patient with agenesis of the cerebellar vermis and cystic renal disease to exclude glutaric aciduria type II. 相似文献
105.
BACKGROUND: Links between cervical spine and/or spinal cord injuries and head trauma have not been reported in detail. METHODS: 188 patients with cervical spine and/or spinal cord injury were divided into two groups, i.e., with upper cervical and mid-lower cervical injury, and compared for head injury. RESULTS: Associated head trauma was investigated in 188 patients with cervical spine and/or spinal cord injuries; 35% had moderate or severe injuries. Brain damage was more frequently observed in patients with upper cervical injury than in those with mid to lower cervical injury. Those patients with upper cervical injury appeared to have an elevated risk of suffering skull base fractures, traumatic subarachnoid hemorrhage, and contusional hemotoma. CONCLUSIONS: Approximately one third of patients with cervical spine and/or spinal cord injuries had moderate or severe head injuries. Brain damage was more frequently associated with upper cervical injury. Those patients with upper cervical injury are at greater risk of suffering from skull base fractures and severe intracranial hematomas than those with mid to lower cervical injury. 相似文献
106.
Prevention of post-operative nausea and vomiting with combined granisetron and droperidol in women undergoing thyroidectomy 总被引:1,自引:0,他引:1
We have compared the efficacy and safety of combined granisetron and droperidol with each anti-emetic alone for preventing post-operative nausea and vomiting after thyroidectomy. In a prospective, randomized, double-blind study, 180 women received granisetron 40 micrograms kg-1, droperidol 20 micrograms kg-1, or granisetron 40 micrograms kg-1 plus droperidol 20 micrograms kg-1 (n = 60 of each) intravenously immediately before induction of anaesthesia. A standard general anaesthetic technique and post-operative analgesia were used. A complete response, defined as no post-operative nausea and vomiting and no need for another rescue anti-emetic, during the first 24 h after anaesthesia occurred in 88%, 60% and 98% of patients who had received granisetron, droperidol and granisetron plus droperidol (P < 0.05; overall Fisher's exact probability test). No clinically important adverse events due to the drugs were observed in any of the groups. In summary, prophylactic use of combined granisetron and droperidol is more effective than each drug alone for the prevention of post-operative nausea and vomiting in female patients undergoing thyroidectomy. 相似文献
107.
This study was undertaken to determine the minimum effective dose of granisetron, 5-hydroxytryptamine type 3 receptor antagonist, for the prevention of post-operative vomiting in children undergoing general inhalational anaesthesia for surgery (inguinal hernia and phimosis). In a randomized, double-blind manner, 120 children, ASA physical status I, aged 4-10 years, were assigned to receive placebo (saline) or granisetron at three different doses (20 micrograms kg-1, 40 micrograms kg-1, 100 micrograms kg-1) intravenously immediately after inhalation induction of anaesthesia (n = 30 of each). A complete response, defined as no emesis and no need for another rescue antiemetic during the first 24 h after anaesthesia, occurred in 57% with placebo, 67% with granisetron 20 micrograms kg-1, 90% with granisetron 40 micrograms kg-1 and 90% with granisetron 100 micrograms kg-1 respectively (P < 0.05; overall Fisher's exact probability test). No clinically important adverse events were observed in any of the groups. Our results suggest that granisetron 40 micrograms kg-1 is the minimum effective dose for the prevention of emesis after paediatric surgery, and that increasing its dose to 100 micrograms kg-1 provides no demonstrable benefit. 相似文献
108.
Transforming growth factor-beta(1) induces apoptosis via connective tissue growth factor in human aortic smooth muscle cells 总被引:6,自引:0,他引:6
We examined the possible involvement of connective tissue growth factor (CTGF) in the apoptosis induced by transforming growth factor-beta(1) (TGF-beta(1)) in human aortic vascular smooth muscle cells (HASC). In quiescent HASC, TGF-beta(1) induced the mRNA and protein of CTGF. A CTGF antisense oligonucleotide inhibited this induction. TGF-beta(1) significantly reduced cell viability and induced DNA fragmentation, and the CTGF antisense oligonucleotide reversed these effects. Moreover, TGF-beta(1) activated caspase 3 in HASC, and the CTGF antisense oligonucleotide reduced this activation. These findings show that CTGF plays a key role in the TGF-beta(1)-induced apoptosis in HASC. 相似文献
109.
Role of Ca2+-activated K+ channels in acetylcholine-induced dilatation of the basilar artery in vivo 下载免费PDF全文
Takanari Kitazono Setsuro Ibayashi Tetsuhiko Nagao Kenichiro Fujii Masatoshi Fujishima 《British journal of pharmacology》1996,120(1):102-106
- We tested the hypothesis that activation of large conductance calcium-activated potassium channels is involved in dilator responses of the basilar artery to acetylcholine in vivo. Using a cranial window in anaesthetized rats, we examined responses of the basilar artery to acetylcholine.
- Topical application of acetylcholine (10−6 and 10−5 M) increased diameter of the basilar artery from 238±7 μm to 268±7 and 288±7 μm, respectively (P<0.05 vs. baseline diameter). Iberiotoxin (10−8 M), an inhibitor of large conductance calcium-activated potassium channels, did not affect baseline diameter of the basilar artery. In the presence of 10−8 M iberiotoxin, 10−6 and 10−5 M acetylcholine increased diameter of the basilar artery from 239±7 μm to 246±7 and 261±7 μm, respectively. Thus, iberiotoxin attenuated acetylcholine-induced dilatation of the basilar artery (P<0.05).
- Sodium nitroprusside (10−7 and 10−6 M) increased diameter of the basilar artery from 242±9 μm to 310±12 and 374±13 μm, respectively (P<0.05 vs. baseline diameter). In the presence of iberiotoxin (10−8 M), sodium nitroprusside (10−7 and 10−6 M) increased diameter of the basilar artery from 243±6 μm to 259±9 and 311±12 μm, respectively. Thus, iberiotoxin attenuated dilator responses of the basilar artery to sodium nitroprusside (P<0.05).
- Iberiotoxin partly inhibited dilator responses of the basilar artery to forskolin, a direct activator of adenylate cyclase, but did not affect vasodilatation produced by levcromakalim, a potassium channel opener.
- These results suggest that dilator responses of the basilar artery to acetylcholine and sodium nitroprusside are mediated, in part, by activation of large conductance calcium-activated potassium channels. Because both acetylcholine and sodium nitroprusside have been shown to activate guanylate cyclase via nitric oxide, activation of large conductance calcium-activated potassium channels may be one of the major mechanisms by which cyclic GMP causes dilatation of the basilar artery in vivo.
110.
Hayashi Takaharu; Sagawa Hiroshi; Kobuke Kyoko; Fujii Kiyomu; Yokozaki Hiroshi; Tahara Eiichi 《Japanese journal of clinical oncology》1996,26(5):368-373
A case of synchronous squamous cell carcinomas in the soft palate,larynx and esophagus is reported, along with findings of molecular-pathologicalanalysis. A biopsy sample from the aryngeal carcinoma revealedwell differentiated squamous cell carcinoma harboring two pointmutations at codons 144 and 148 of the p53 gene but not at codon299, and more than 50% of the cancer cells showed accumulationof p53 protein immunohistochemically. The esophageal tumor,which was moderately differentiated squamous cell carcinoma,showed immunoreactivity for p53 within the nuclei of 2550%of cancer cells with a missense mutation at codon 299 but notat codon 144 or 148. This cancer also showed immunoreactivityfor transforming growth factor alpha. On the other hand, thepoorly differentiated squamous cell carcinoma in the soft palateshowed negative immunoreactivity for p53 and no point mutationin exons 5 to 8 of the gene. These results suggest that thethree synchronous squamous cell carcinomas arose as independentevents. 相似文献