全文获取类型
收费全文 | 6605篇 |
免费 | 480篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 199篇 |
妇产科学 | 73篇 |
基础医学 | 919篇 |
口腔科学 | 229篇 |
临床医学 | 648篇 |
内科学 | 1670篇 |
皮肤病学 | 140篇 |
神经病学 | 484篇 |
特种医学 | 454篇 |
外科学 | 899篇 |
综合类 | 117篇 |
一般理论 | 1篇 |
预防医学 | 324篇 |
眼科学 | 127篇 |
药学 | 405篇 |
中国医学 | 5篇 |
肿瘤学 | 387篇 |
出版年
2021年 | 60篇 |
2018年 | 81篇 |
2017年 | 78篇 |
2016年 | 78篇 |
2015年 | 79篇 |
2014年 | 121篇 |
2013年 | 204篇 |
2012年 | 190篇 |
2011年 | 204篇 |
2010年 | 131篇 |
2009年 | 136篇 |
2008年 | 226篇 |
2007年 | 217篇 |
2006年 | 209篇 |
2005年 | 189篇 |
2004年 | 159篇 |
2003年 | 169篇 |
2002年 | 155篇 |
2001年 | 207篇 |
2000年 | 193篇 |
1999年 | 182篇 |
1998年 | 141篇 |
1997年 | 141篇 |
1996年 | 143篇 |
1995年 | 106篇 |
1994年 | 104篇 |
1993年 | 108篇 |
1992年 | 175篇 |
1991年 | 169篇 |
1990年 | 171篇 |
1989年 | 202篇 |
1988年 | 178篇 |
1987年 | 155篇 |
1986年 | 154篇 |
1985年 | 126篇 |
1984年 | 108篇 |
1983年 | 72篇 |
1982年 | 71篇 |
1981年 | 82篇 |
1980年 | 85篇 |
1979年 | 85篇 |
1978年 | 83篇 |
1977年 | 69篇 |
1976年 | 75篇 |
1975年 | 68篇 |
1972年 | 65篇 |
1970年 | 64篇 |
1965年 | 67篇 |
1964年 | 56篇 |
1960年 | 70篇 |
排序方式: 共有7125条查询结果,搜索用时 484 毫秒
991.
992.
Rod and cone contributions to S-potentials from the cat retina 总被引:5,自引:0,他引:5
R H Steinberg 《Vision research》1969,9(11):1319-1329
993.
H C Stevenson A F Gazdar R I Linnoila E K Russell H K Oie S M Steinberg D C Ihde 《Journal of clinical oncology》1989,7(7):923-931
The ability to establish a continuously growing tumor cell line from fresh tumor specimens has been associated with shortened survival in some human malignancies. Therefore, we assessed the relationship between survival and in vitro tumor cell growth from specimens obtained during routine staging procedures in 68 consecutive patients with untreated, extensive-stage small-cell lung cancer (SCLC) who received etoposide/cisplatin chemotherapy. Three groups of SCLC patients could be distinguished: (1) 23 patients in whom a tumor cell line was established in vitro; (2) 28 patients in whom tumor-containing specimens were cultured but in vitro growth did not occur; and (3) 17 patients in whom no tumor-containing specimen could be procured. No significant difference in response rates to chemotherapy of the three groups was noted. Poor performance status (P2 = .001), male gender (P2 = .0008), liver metastases (P2 = .0033), brain metastases (P2 = .0152), and the ability to obtain a tumor-containing specimen from the patient for laboratory culture (P2 = .0005) were all significant independent predictors of decreased survival in this patient population. While the ability to obtain a tumor cell specimen for cell culture using routine staging and diagnostic procedures identified patients with shortened survival, we found no significant survival differences between patients whose tumor cell specimens grew in cell culture v those that did not (median survival of 7 months v 11 months, P2 = .72). Our study indicates that the clinical outcome of extensive-stage SCLC patients from whom tumor cell lines can be established is not significantly different than in those cases from whom tumor-containing specimens could not be grown in vitro. 相似文献
994.
W E Torres D E Maurer H V Steinberg S Robbins M E Bernardino 《AJR. American journal of roentgenology》1988,150(6):1317-1319
Aortic calcification, either mural or thrombus, is a common finding in patients with abdominal aortic aneurysms. Differentiating between the two sites of calcification is necessary in order to avoid confusing simple thrombus calcification with displaced calcified intima in aortic dissection. The CT scans of 145 cases of abdominal aortic aneurysm and seven cases of abdominal aortic aneurysm with dissection were analyzed with respect to the location of the calcification: mural only or mural and thrombus. Mural calcification was seen in all 152 patients with aneurysms whereas thrombus calcification was identified in only 33 (24%) of the 136 patients with thrombus. Displaced intimal calcification caused by aortic dissection can either appear similar to or, at times, be indistinguishable from thrombus calcification. Thrombus calcification was present in four (57%) of the seven patients with abdominal aortic aneurysms and dissection. To avoid the possibility of a false-positive diagnosis of aortic dissection in patients with abdominal aortic aneurysm, other signs of aortic dissection should be sought such as separation of the true and false lumina by an intimal flap. 相似文献
995.
Matson GB; Twieg DB; Karczmar GS; Lawry TJ; Gober JR; Valenza M; Boska MD; Weiner MW 《Radiology》1988,169(2):541-547
Localized phosphorus-31 magnetic resonance (MR) spectroscopy in humans has previously been accomplished with surface coils by means of depth-resolved surface coil spectroscopy or rotating frame experiments, in which the extent of tissue sampled critically depends on surface coil placement. The authors' goal was to modify the surface coil image-selected in vivo spectroscopy (ISIS) experiment to accomplish three-dimensional volume selection through application of selective pulses in the presence of B0 gradients. Advantages of ISIS include the ability to use proton images to define the volume of interest (VOI) and reduced dependence on exact positioning of the surface coil. However, rapid replication of the surface coil ISIS experiment can cause spectral contamination from signals originating outside the VOI. A modified version of the ISIS experiment was developed to alleviate contamination under conditions of rapid replication. Applications of localized P-31 MR spectroscopy for observation of high-energy phosphorus metabolites are presented in human liver, heart, and transplanted and normal kidney. 相似文献
996.
997.
998.
Marvin E. Steinberg Laurence D. Cohen Charles R. McCrae 《The Journal of surgical research》1973,14(3):247-253
An experimental antigen-induced arthritis has been described which closely resembles human rheumatoid arthritis. The effectiveness of intra-articular 5-fluorouracil (5-FU) in combatting the initial stages of this reaction has been confirmed. These studies also indicate that there is no necessity for pretreatment or immediate treatment, so long as the drug is administered relatively early in the course of the disease. Although further animal experimentation is required to establish the mechanisms of action and to determine the long term effects of 5-FU, its possible role in the management of human rheumatoid arthritis might be given further consideration. 相似文献
999.
1000.
Fiberenboscopic Removal of Long Foreign Bodies from the Stomach Using a Colon Stiffening Tube as a Protective Sheath 总被引:1,自引:0,他引:1
WILLIAM C. MARTIN M.D. STEPHEN A. JONES M.D. NORIYOSHI NAGAI M.D E. CLINTON TEXTER JR. M.D. F.A.C.G. 《The American journal of gastroenterology》1979,71(5):505-507
A colonoscopic stiffening tube was effectively used as a protective sheath in the esophagus during the endoscopic removal of a long ballpoint pen and a writing pencil from the stomach. 相似文献