全文获取类型
收费全文 | 7958篇 |
免费 | 680篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 59篇 |
儿科学 | 365篇 |
妇产科学 | 226篇 |
基础医学 | 918篇 |
口腔科学 | 151篇 |
临床医学 | 937篇 |
内科学 | 1368篇 |
皮肤病学 | 55篇 |
神经病学 | 706篇 |
特种医学 | 453篇 |
外科学 | 1270篇 |
综合类 | 170篇 |
一般理论 | 2篇 |
预防医学 | 738篇 |
眼科学 | 180篇 |
药学 | 545篇 |
中国医学 | 4篇 |
肿瘤学 | 508篇 |
出版年
2021年 | 99篇 |
2020年 | 67篇 |
2019年 | 97篇 |
2018年 | 124篇 |
2017年 | 93篇 |
2016年 | 97篇 |
2015年 | 113篇 |
2014年 | 145篇 |
2013年 | 255篇 |
2012年 | 302篇 |
2011年 | 339篇 |
2010年 | 185篇 |
2009年 | 158篇 |
2008年 | 306篇 |
2007年 | 336篇 |
2006年 | 338篇 |
2005年 | 295篇 |
2004年 | 293篇 |
2003年 | 265篇 |
2002年 | 264篇 |
2001年 | 284篇 |
2000年 | 287篇 |
1999年 | 266篇 |
1998年 | 167篇 |
1997年 | 138篇 |
1996年 | 135篇 |
1995年 | 126篇 |
1994年 | 118篇 |
1993年 | 91篇 |
1992年 | 201篇 |
1991年 | 187篇 |
1990年 | 189篇 |
1989年 | 163篇 |
1988年 | 187篇 |
1987年 | 138篇 |
1986年 | 171篇 |
1985年 | 159篇 |
1984年 | 143篇 |
1983年 | 122篇 |
1982年 | 81篇 |
1981年 | 69篇 |
1980年 | 56篇 |
1979年 | 109篇 |
1978年 | 75篇 |
1977年 | 72篇 |
1976年 | 60篇 |
1975年 | 74篇 |
1974年 | 74篇 |
1973年 | 77篇 |
1972年 | 62篇 |
排序方式: 共有8655条查询结果,搜索用时 15 毫秒
61.
J.P. Neoptolemos M. G.T. Raraty P. Ghaneh H. Hickey D.D. Stocken J. A. Dunn H. Friess M.W. Büchler 《Der Chirurg》2003,74(3):191-201
Recent advances have been made in the treatment of pancreas cancer. Specialized pancreas centres have reported an increasing rate of resections with reduced postoperative mortality. On account of the highly aggressive nature of pancreas cancer, there is a great challenge in identifying effective therapy concepts for advanced stages of the cancer as well as for the development of resection-associated measures. As large-scale, randomised, controlled studies are lacking, the additive therapy concepts after resection do not have a sufficiently scientific basis. The ESPAC-1 study, which included 600 patients, surpassed all previous studies on adjuvant therapy for pancreas cancer. This study has shown,for example, that the most promising adjuvant chemotherapy with 5-fluorouracil and folic acid leads to an equal if not better result than the multimodal regimen. This regimen can be superseded with the use of Gemcitabine, which will be evaluated in the ESPAC-3 study that includes 990 patients from various European countries including Germany, as well as from Canada and Australia. Participation in the large, phase-3 study therefore plays a key role in the continued development of the management of pancreas cancer. 相似文献
62.
63.
64.
Donor hyperglycemia as a minor risk factor and immunologic variables as major risk factors for pancreas allograft loss in a multivariate analysis of a single institution''s experience.
下载免费PDF全文
![点击此处可从《Annals of surgery》网站下载免费的PDF全文](/ch/ext_images/free.gif)
P F Gores K J Gillingham D L Dunn K C Moudry-Munns J S Najarian D E Sutherland 《Annals of surgery》1992,215(3):217-230
The impact of multiple donor and recipient variables on functional survival of 307 cadaveric pancreas allografts transplanted in 253 recipients at the authors' institution between July 25, 1978 and September 4, 1990 was determined using the Cox proportional hazards regression model. Relative risk of graft loss was calculated for all cases as well as for technically successful (TS) ones. Factors with an impact in descending order of significance for TS cases were immunosuppression (RR = 3.9 for double-drug versus triple-drug maintenance, p less than 0.0001); recipient category (RR = 2.4 for pancreas alone versus simultaneous pancreas/kidney, p = 0.009); retransplantation (RR = 1.8 for retransplants versus primary grafts, p = 0.007); donor hyperglycemia (RR = 1.7 for blood glucose greater than or equal to 200 versus less than 200 mg/dL, p = 0.02); human leukocyte antigen (HLA) matching (RR = 2.1 for poor versus a good match, p = 0.04). A logistic regression analysis also was performed to determine which factors predisposed to technical failure; none were identified. To make the model as relevant as possible to their current program, the authors analyzed only the bladder-drained cases (n = 221; 1984 to 1990). All patients received triple therapy. Recipient category, retransplantation, donor hyperglycemia, and degree of HLA matching remained as significant risk factors. Construction of estimated survival curves showed that the results of retransplantation were significantly improved, and the penalty incurred by using hyperglycemic donors was partially ameliorated by using well-matched donors. Because preservation times up to 30 hours did not exert an adverse effect on outcome, an argument is made to share pancreata between centers to achieve good matches. 相似文献
65.
The role of intestinal flora on the interactions between nonparenchymal cells and hepatocytes in coculture 总被引:2,自引:0,他引:2
T R Billiar M A Maddaus M A West D L Dunn R L Simmons 《The Journal of surgical research》1988,44(4):397-403
Kupffer cells are exposed directly to a number of factors in the portal circulation that can modify or regulate their responses to septic stimuli. The gut represents a potential source of a number of these factors including endotoxin, lymphokines, and prostaglandins. We examined Kupffer cells from germfree rats and germfree rats exposed to endotoxin or bacteria via their GI tracts to determine the importance of the intestinal flora in maintaining or modulating Kupffer cell responses. Kupffer cells from germfree animals were reduced in numbers and failed to respond to LPS in Kupffer cell: hepatocyte coculture. When germfree rats were exposed to bacterial endotoxin or bacteria via the gastrointestinal tract their Kupffer cells increased in numbers to normal and the cells responded to LPS in culture. Intestinal overgrowth with Escherichia coli for 2 days activated the Kupffer cells and significantly increased Kupffer cell sensitivity to LPS. These data suggest that the environment of the gastrointestinal tract is important for normal Kupffer cell responses and that intestinal bacterial overgrowth can modify Kupffer cell responses to septic stimuli. 相似文献
66.
67.
Localization of Helicobacter pylori urease and heat shock protein in human gastric biopsies. 总被引:7,自引:0,他引:7
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
B E Dunn N B Vakil B G Schneider M M Miller J B Zitzer T Peutz S H Phadnis 《Infection and immunity》1997,65(4):1181-1188
Helicobacter pylori is a spiral, gram-negative bacterium which causes chronic gastritis and plays a critical role in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori expresses significant urease activity which is an essential virulence factor. Since a significant fraction of urease activity is located on the surface of the bacterium, the urease molecule is a logical choice as an antigen for a vaccine; currently recombinant urease apoenzyme is being tested as a vaccine in phase II clinical trials. We have recently demonstrated that urease and HspB (a homolog of the GroEL heat shock protein) become associated with the surface of H. pylori in vitro in a novel manner: these cytoplasmic proteins are released by bacterial autolysis and become adsorbed to the surface of intact bacteria, reflecting the unique characteristics of the outer membrane. To determine if similar mechanisms are operative in vivo, we determined the ultrastructural locations of urease and HspB within bacteria present in human gastric biopsies. Our results demonstrate that both urease and HspB are located within the cytoplasm of all bacteria examined in human gastric biopsies. Interestingly, a significant proportion of the bacteria examined also possessed variable amounts of surface-associated urease and HspB antigen (from 5 to 50% of the total antigenic material), indicating that in vivo, H. pylori has surface characteristics which enable it to adsorb cytoplasmic proteins. This is consistent with our altruistic autolysis model in which H. pylori uses genetically programmed bacterial autolysis to release urease and other cytoplasmic proteins which are subsequently adsorbed onto the surface of neighboring viable bacteria. These observations have important implications regarding pathogenesis and development of vaccines for H. pylori. 相似文献
68.
Introduction : Hypertrophic scar is a devastating sequel to burns and other tangential skin injuries. It follows deep dermal injuries and does not occur after superficial injuries. Nitric oxide (NO) plays many important roles in wound healing from inflammation to scar remodeling. Studies have shown that expression of nitric oxide synthase and nitric oxide production are decreased in human hypertrophic scar. However little is known about NO involvement in the early stages of hypertrophic scarring, because of the lack of an animal model. It was recently reported that the female red Duroc pig (FRDP) makes thick scar, which is similar to human hypertrophic scar. We hypothesized that NO production in wounds on the female, red Duroc pig is similar to that of human hypertrophic scar and that NO involvement in deep wounds is different from that in superficial wounds. Methods : Superficial (0.015” to 0.030”) and deep (0.045” to 0.060”) wounds were created on the backs of four FRDPs. Biopsies were collected at weeks 1.5, 4, 8 and 21 post wounding including samples of uninjured skin. Nitric oxide levels were measured with the Griess reaction assay and normalized with tissue protein level. Results : Superficial wounds healed with an invisible scar whereas the deep wounds healed with scar resembling mild hypertrophic scar. The thickness of the scars from the deep wounds was significantly greater than uninjured skin and healed superficial wounds (p < 0.01). NO levels were increased at 1.5 weeks in deep wounds compared to superficial wounds and uninjured skin (p < 0.05). At 8 weeks, NO levels in deep wounds had returned to the level of uninjured tissue and superficial wounds. By 21 weeks, NO levels had decreased significantly when compared to superficial wounds (p < 0.01). There were no differences in NO levels between uninjured skin and superficial wounds at any time point (p > 0.05). Conclusions : NO production is similar in late, deep wounds on the female, red Duroc pig to that reported in the literature for human hypertrophic scar further validating this animal model. NO production is quite different after deep wounds as compared to superficial wounds in the FRDP. Early elevation in nitric oxide production might account for excessive inflammation in deep wounds that become thick scars in the FRDP. Nitric oxide regulators and effects at early stages of scar formation should be elucidated further and the FRDP appears to be a useful model. 相似文献
69.
Analgetic and antiinflammatory 7-aroylbenzofuran-5-ylacetic acids and 7-aroylbenzothiophene-5-ylacetic acids 总被引:1,自引:0,他引:1
A number of 7-benzoylbenzofuran-5-ylacetic acids and 7-benzoylbenzothiophene-5-ylacetic acids were synthesized. The compounds were generally only 1/2 to 3 times as potent as phenylbutazone in the rat paw edema antiinflammatory assay. However, they show greater activity as analgetic agents. The most active compound is 7-[4-(methylthio)-benzoyl]benzofuran-5-ylacetic acid (5g) having 57 times the potency of aspirin in the mouse writhing analgetic assay. This compound caused virtually no gastric ulceration in rats at doses of up to 90 mg/kg. 相似文献
70.