首页 | 官方网站   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   7422篇
  免费   327篇
  国内免费   47篇
医药卫生   7796篇
  2023年   43篇
  2022年   64篇
  2021年   138篇
  2020年   74篇
  2019年   89篇
  2018年   130篇
  2017年   102篇
  2016年   125篇
  2015年   148篇
  2014年   211篇
  2013年   216篇
  2012年   375篇
  2011年   353篇
  2010年   268篇
  2009年   212篇
  2008年   434篇
  2007年   419篇
  2006年   436篇
  2005年   483篇
  2004年   487篇
  2003年   489篇
  2002年   535篇
  2001年   168篇
  2000年   160篇
  1999年   138篇
  1998年   107篇
  1997年   115篇
  1996年   107篇
  1995年   105篇
  1994年   83篇
  1993年   88篇
  1992年   122篇
  1991年   120篇
  1990年   121篇
  1989年   105篇
  1988年   65篇
  1987年   55篇
  1986年   50篇
  1985年   46篇
  1984年   37篇
  1983年   20篇
  1982年   18篇
  1981年   17篇
  1980年   14篇
  1978年   18篇
  1977年   9篇
  1976年   7篇
  1975年   9篇
  1974年   15篇
  1971年   7篇
排序方式: 共有7796条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: The therapies for refractory ulcers on the oral mucosa are symptomatic and very unsatisfactory. We hypothesized that application of growth factors might be able to achieve successful remission of the lesion. We evaluated the effects of systemic administration and topical application of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on impaired wound healing of ulcers in the rabbit gingiva. METHODS: Almost uniform round ulcers could be created on the gingiva of the rabbits by chemical injury with acetic acid. When the submandibular glands were removed or i.v. injection of cisplatin (CDDP) and peplomycin sulfate was performed before ulcer formation, healing of the ulcers took longer than in untreated rabbits. To ascertain whether or not human EGF and bFGF affect rabbit cells, we first examined the effects of EGF and bFGF on the proliferation of the cells derived from rabbit gingiva. We then applied EGF or bFGF in these impaired healing models. RESULTS: EGF and bFGF promoted proliferation of the fibroblasts, and EGF also promoted proliferation of the keratinocytes isolated from gingival tissue of rabbits in vitro. Systemic injections of EGF and bFGF in rabbits, which had their submandibular glands removed, and topical application of bFGF accelerated healing of ulcers created in rabbits injected with CDDP and peplomycin sulfate. The ability of bFGF to promote the healing of ulcers was much greater than that of EGF. CONCLUSION: Basic FGF may be effective for refractory oral mucosal lesions.  相似文献   
2.
3.
1. Endothelium-dependent relaxation in response to acetylcholine (ACh) and the calcium ionophore A 23187 was examined in aorta, coronary, basilar and renal arteries isolated from Watanabe heritable hyperlipidaemic (WHHL) rabbits of 2, 6 and 12 months of age, with normolipidaemic heterozygous WHHL rabbits as controls. 2. In the rings of WHHL rabbit aortae and coronary arteries preconstricted with vasoconstrictors, endothelium-dependent relaxation in response to ACh was attenuated with age compared to the heterozygous WHHL rabbits. A significant negative correlation was found between the total cholesterol content and the relaxation response to ACh in the aortae or coronary arteries from 6 and 12 month old WHHL rabbits. 3. In the rings of basilar arteries, endothelium-dependent relaxations to ACh were not modified with age. Similarly, in the rings of renal arteries, the relaxation response to ACh was not changed with age, but in the 6 and 12 month preparations, after the age of 6 months, a contraction following the relaxation appeared at higher concentrations of ACh (10?7 to 10?6 mol/L). The contraction was endothelium-dependent and inhibited by indomethacin. 4. A 23187-induced endothelium-dependent relaxations were also markedly attenuated in the aorta and significantly in the coronary artery with age. 5. Endothelium-independent relaxation to sodium nitroprusside was not changed in all arteries from WHHL rabbits of different ages. 6. These findings indicate that in the aorta and coronary artery of the WHHL rabbit, the endothelium-dependent relaxation to ACh and A 23187 becomes impaired with increasing age (i.e., with the progression of cholesterol deposition in the arterial wall) but is preserved in the basilar and renal artery.  相似文献   
4.
5.
In ongoing reviews of 339 patients with surgically treated primary squamous cell carcinoma, there were 19 (5.6%) with concurrent gastric cancer and 11 (3.2%) with head and neck cancer. The incidences of intra-esophageal multiple occurrence of esophageal cancer are 27.3% and 26.3% in those with associated head and neck cancer and gastric cancer, respectively, and higher than 7.1% in those without such a concurrent cancer. There was no difference in the clinicopathological characteristics of those with concurrent head and neck and gastric cancers, except for the higher incidence of metachronous occurrence in the former. These findings suggest that, in cases of esophageal cancer associated with concurrent head and neck cancer and gastric cancer, intraesophageal multiplicity of the esophageal carcinoma is frequent and that preoperative serial evaluations is most important to design treatment and estimate the prognosis.  相似文献   
6.
7.
OBJECTIVE: It has been observed that a systemic inflammatory response after on-pump coronary artery bypass grafting (CABG) participates in the pathogenesis of postoperative atrial fibrillation (AF). In patients undergoing off-pump CABG, it is plausible that inflammation is associated with the development of postoperative AF. The present study examined relation of proinflammatory cytokines, which play an important role in the upstream of inflammatory cascade, to the development of AF after off-pump CABG. METHODS: The present study included 39 patients undergoing off-pump CABG. Tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-8, were measured by enzyme-linked immunosorbent assay, on anesthetic induction, after sternotomy before anastomoses, at the completion of anastomoses, 3 and 6h thereafter, and on postoperative days (POD) 1-4. C-reactive protein (CRP) was also measured by turbidimetric immunoassay, preoperatively, and on POD 1, 2, 3, 6, 9, and 13. RESULTS: Eleven patients (28%) developed postoperative AF. Patients with postoperative AF were older (70+/-6.4 years vs 60+/-8.8 years, P=0.001); however, there was no difference in other pre- and perioperative variables. TNF-alpha level did not change during the study period. However, IL-8 and CRP levels significantly increased after the surgery, although there was no significant difference between the two groups. IL-6 level also increased after the surgery with its peak at 6h after the completion of anastomoses. IL-6 levels of 3 and 6h after anastomoses were significantly higher in patients with postoperative AF (360+/-143 pg/ml vs 230+/-94 pg/ml, P=0.0047, 435+/-175 pg/ml vs 247+/-102 pg/ml, P=0.0005, respectively). Logistic regression analysis indicated that the highest quartile of IL-6 level immediately after the surgery (odds ratio 7.63; 95% CI, 1.06-54.9; P=0.04) and age (odds ratio 1.18; 95% CI, 1.01-1.39; P=0.04) independently predict postoperative AF. Furthermore, the maximum level of IL-6 immediately after the surgery significantly correlated to age and intraoperative blood loss (r=0.04, P=0.01, and r=0.47, P=0.04, respectively). CONCLUSIONS: Advanced age was a major risk factor for postoperative AF. Furthermore, inflammatory response induced by surgical trauma was also associated with the development of AF after off-pump CABG.  相似文献   
8.
We compared the cytotoxic effects of two anthracycline derivatives, epirubicin (EPI) and adriamycin (ADM), against human tumor cells in vitro. Various tumor specimens, obtained at surgery, included 57 liver, 19 lung, 16 gastric, 10 colorectal and 7 breast cancer specimens. These tumor cells were exposed to the same concentration of EPI or ADM for 3 days. The chemosensitivity of each tumor cell type to each drug was then assayed using the in vitro succinate dehydrogenase inhibition (SDI) test. Sensitivity to the treatment was defined as a 50% or greater reduction in the succinate dehydrogenase (SD) activity of the tumor cells, relative to that of the control (untreated) cells. Each cell type, except for gastric cancer cells, was equally sensitive to EPI and ADM. Gastric cancer cells were more sensitive to EPI than to ADM (P less than 0.05). The rate of coincidence, the sum of the co-sensitive and co-resistant rates of all the tumors, was quite high (90.8%). Thus, these findings indicate that EPI and ADM are equally cytotoxic to each tumor cell type, but EPI is more cytotoxic than ADM to gastric cancer cells. Since EPI is reported to be less cardiotoxic than ADM, EPI may replace ADM in cancer chemotherapy.  相似文献   
9.
An early gastric carcinoma, measuring 1.7 X 0.6 cm, had already metastasized to the extra-perigastric lymph node in a 71 year old symptom-free man. Radiographic and endoscopic studies showed a small depressed lesion on the lesser curvature of the antrum and histology of the biopsied specimen revealed a well differentiated adenocarcinoma. Under the diagnosis of IIc type intramucosal carcinoma, partial gastrectomy and wide lymph node dissection was performed. Pathologic study of the resected specimen showed that the cancer cells had invaded the submucosa at an area via a lymphatic vessel and that only one lymph node along the common hepatic artery was involved.  相似文献   
10.
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-23

京公网安备 11010802026262号