全文获取类型
收费全文 | 262203篇 |
免费 | 37680篇 |
国内免费 | 3239篇 |
专业分类
耳鼻咽喉 | 6416篇 |
儿科学 | 8667篇 |
妇产科学 | 5192篇 |
基础医学 | 18943篇 |
口腔科学 | 3880篇 |
临床医学 | 35484篇 |
内科学 | 72073篇 |
皮肤病学 | 9776篇 |
神经病学 | 25178篇 |
特种医学 | 10347篇 |
外国民族医学 | 23篇 |
外科学 | 55426篇 |
综合类 | 1953篇 |
现状与发展 | 72篇 |
一般理论 | 58篇 |
预防医学 | 13873篇 |
眼科学 | 5221篇 |
药学 | 9960篇 |
3篇 | |
中国医学 | 567篇 |
肿瘤学 | 20010篇 |
出版年
2024年 | 745篇 |
2023年 | 5322篇 |
2022年 | 2675篇 |
2021年 | 5591篇 |
2020年 | 7439篇 |
2019年 | 4382篇 |
2018年 | 9919篇 |
2017年 | 9240篇 |
2016年 | 10453篇 |
2015年 | 10771篇 |
2014年 | 18598篇 |
2013年 | 20011篇 |
2012年 | 11743篇 |
2011年 | 11988篇 |
2010年 | 14327篇 |
2009年 | 17659篇 |
2008年 | 11355篇 |
2007年 | 9856篇 |
2006年 | 11999篇 |
2005年 | 9054篇 |
2004年 | 8482篇 |
2003年 | 7213篇 |
2002年 | 7222篇 |
2001年 | 7533篇 |
2000年 | 6673篇 |
1999年 | 6218篇 |
1998年 | 4871篇 |
1997年 | 4409篇 |
1996年 | 4223篇 |
1995年 | 4034篇 |
1994年 | 2642篇 |
1993年 | 2245篇 |
1992年 | 3163篇 |
1991年 | 3159篇 |
1990年 | 2547篇 |
1989年 | 2628篇 |
1988年 | 2337篇 |
1987年 | 2035篇 |
1986年 | 2055篇 |
1985年 | 1751篇 |
1984年 | 1309篇 |
1983年 | 1222篇 |
1982年 | 963篇 |
1981年 | 796篇 |
1980年 | 723篇 |
1979年 | 874篇 |
1978年 | 746篇 |
1977年 | 767篇 |
1975年 | 715篇 |
1972年 | 726篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
The pancreas gives rise to a remarkable variety of neoplasms other than ductal adenocarcinoma. Although no individual type of tumor in this category is prevalent enough to qualify as common, most types are currently encountered with a frequency far greater than that in decades of the recent past. This change is largely the result of the expanded use of contemporary abdominal imaging. The unusual tumors of the pancreas vary greatly in their biologic behavior and, accordingly, in their clinical consequences and therapeutic requirements. Accurate diagnosis, therefore, can be of considerable clinical relevance. Not only is it worthwhile to distinguish one type of unusual pancreatic tumors from another, it is perhaps of even greater consequence to distinguish the unusual tumors from ordinary pancreatic adenocarcinomas. The goals of this discussion are to expand radiologic awareness of these uncommon but interesting pancreatic neoplasms and to increase familiarity with their diagnostically salient features. 相似文献
993.
994.
Extended resection for locally advanced colorectal carcinoma 总被引:2,自引:0,他引:2
995.
Background: Percutaneous closed needle biopsy of musculoskeletal neoplasms has gained in popularity. However, it remains controversial
whether or not to resect the needle tract for fear of a local recurrence. A single published case report exists, noting the
lone tract recurrence of an extremity skeletal osteosarcoma.
Methods: We report on three additional individuals who demonstrated that tract local recurrences may occur after a closed needle biopsy
for nonosteosarcoma, nonextremity sarcomas. For perspective, the world literature is reviewed to identify tract recurrences
for other malignancies and the results of needle biopsy in musculoskeletal neoplasms.
Results: Eighty-nine percent of needle tract local recurrences occur when carcinomas are subjected to biopsy, as reported in the literature.
Forty-seven cases since 1950 are described representing essentially all tumor types. The nature of musculoskeletal neoplasms
makes closed biopsy more difficult than for softer, more homogeneous, and easier to access neoplasms.
Conclusions: Local recurrences of sarcoma may occur in closed needle biopsy tracts. Strong consideration should be given to open biopsy
and tract resection. 相似文献
996.
Comparison of p53 expression in proximal and distal gastric cancer: Histopathologic correlation and prognostic significance 总被引:2,自引:0,他引:2
Huihuan Tang MD Shuichi Hokita MD PhD Xiangming Che MD Masamichi Baba MD PhD Kuniaki Aridome MD PhD Fumio Kijima MD Gen Tanabe MD PhD Sonshin Takao MD PhD Dr. Takashi Aikou MD PhD 《Annals of surgical oncology》1997,4(6):470-474
Background: The overexpression of p53 has been found to be correlated with prognosis of some carcinomas, including gastric cancer, but
no studies have reported on its relationship to the location of gastric cancer. In the present study, we compared the p53
expression of proximal and distal gastric cancer concerning histopathology and prognosis.
Methods: A total of 170 tumors in the patients with proximal (80 cases) and distal (90 cases) gastric cancer were studied by immunohistochemical
methods.
Results: p53 immunopositivity was detected in 28.8% of all tumors. The p53-positive expression in proximal gastric cancer was higher
than in distal gastric cancer (38.8% vs. 20.0%, p<0.05). A 5-year survival analysis showed that there is no significant difference
between tumors that are p53 positive and p53 negative. No correlation was found between p53 expression and histopathology
of gastric cancer.
Conclusion: p53 nuclear staining is not useful as a prognostic indicator or as a parameter in gastric cancer. 相似文献
997.
Dr. Seema A. Khan MD Nick J. Gonchoroff DrPH Linda E. Miller PhD 《Annals of surgical oncology》1997,4(6):462-469
Background: Many studies have addressed the effect of the timing of surgery for breast cancer relative to menstrual cycle phase, with
conflicting results. Explanations for the possibility that survival could be altered by the appropriate timing of breast cancer
surgery in humans remain speculative.
Methods: We examined the expression of three estrogen related proteins (c-erbB-2, cathepsin D, pS2) in the breast tumors from 69 premenopausal women sampled in different phases of the menstrual cycle.
Data on S-phase fraction and hormone receptor expression were also analyzed. Immunohistochemical assays were used to measure
the proteins of interest. S-phase fraction was determined by flow cytometry. Analyses were performed based on fraction of
cells staining positive for the protein, density of stain, and a histoscore that combined both fraction of positive cells
and density.
Results: We found no differences in c-erbB-2, cathepsin D, hormone receptor, or S-phase levels in tumors sampled in the follicular versus luteal phase, or perimenstrual
versus periovulatory phase. The exception was pS2, which was expressed at greater levels during the luteal than during the
follicular phase of the cycle (p<0.01); but there was no difference in pS2 expression when the patients were classified as
periovulatory versus perimenstrual.
Conclusions: Our findings do not support a variation in c-erbB-2, cathepsin D, S-phase fraction, or receptor expression as an explanation for the differences in breast cancer prognosis
when surgery is timed by menstrual cycle phase. The finding that pS2 (an indicator of hormone sensitivity, and possibly better
prognosis) is expressed at higher levels in tumor samples during the luteal phase suggests that the biologic profile of breast
tumors may vary with the menstrual cycle and that these variations deserve further study. 相似文献
998.
999.
1000.