全文获取类型
收费全文 | 64986篇 |
免费 | 3661篇 |
国内免费 | 727篇 |
专业分类
耳鼻咽喉 | 1177篇 |
儿科学 | 732篇 |
妇产科学 | 929篇 |
基础医学 | 11093篇 |
口腔科学 | 1505篇 |
临床医学 | 5569篇 |
内科学 | 12097篇 |
皮肤病学 | 2361篇 |
神经病学 | 4752篇 |
特种医学 | 3638篇 |
外科学 | 8656篇 |
综合类 | 246篇 |
现状与发展 | 1篇 |
一般理论 | 19篇 |
预防医学 | 3060篇 |
眼科学 | 1546篇 |
药学 | 5787篇 |
中国医学 | 727篇 |
肿瘤学 | 5479篇 |
出版年
2023年 | 500篇 |
2022年 | 1562篇 |
2021年 | 2378篇 |
2020年 | 1193篇 |
2019年 | 1568篇 |
2018年 | 1981篇 |
2017年 | 1488篇 |
2016年 | 2148篇 |
2015年 | 3098篇 |
2014年 | 3638篇 |
2013年 | 4136篇 |
2012年 | 6164篇 |
2011年 | 5634篇 |
2010年 | 3338篇 |
2009年 | 2811篇 |
2008年 | 3888篇 |
2007年 | 3578篇 |
2006年 | 3050篇 |
2005年 | 2758篇 |
2004年 | 2308篇 |
2003年 | 1940篇 |
2002年 | 1686篇 |
2001年 | 1434篇 |
2000年 | 1305篇 |
1999年 | 952篇 |
1998年 | 398篇 |
1997年 | 279篇 |
1996年 | 226篇 |
1995年 | 198篇 |
1994年 | 160篇 |
1993年 | 144篇 |
1992年 | 348篇 |
1991年 | 333篇 |
1990年 | 296篇 |
1989年 | 272篇 |
1988年 | 257篇 |
1987年 | 261篇 |
1986年 | 184篇 |
1985年 | 169篇 |
1984年 | 132篇 |
1983年 | 118篇 |
1982年 | 62篇 |
1981年 | 68篇 |
1979年 | 84篇 |
1978年 | 75篇 |
1975年 | 51篇 |
1974年 | 62篇 |
1973年 | 56篇 |
1972年 | 52篇 |
1970年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Mi Sook Gwak Kwang-Woong Lee Shi Yeon Kim Jihyun Lee Jae Won Joh Sung Joo Kim Hwan Hyo Lee Jean Wan Park Gaab Soo Kim Suk-Koo Lee 《Liver transplantation》2005,11(3):331-335
During liver transplantation for hepatocellular carcinoma (HCC) patients, HCC could theoretically be introduced into the systemic circulation when salvaged blood is used with an autotransfusion device. Several reports have shown that some types of leukocyte depletion filters (LDFs) could completely reduce the risk for reintroducing some types of tumor cells. In this study, we tested the ability of the LDF (RCEZ1T, Pall Biomedical Co, NY, USA) to reduce the risk for reintroducing HCC cells in vitro by using a very sensitive detection method. We divided the test group into 6 groups: group I was 10 cells, group II was 20 cells, group III was 2 x 10(3) cells, group IV was 2 x 10(5) cells, group V was 2 x 10(6) cells, and group VI was 2 x 10(7) cells. The counted cells in 200 mL saline were passed through the RCEZ1T using the force of gravity. To identify the presence of cells, the pellet was resuspended, and polymerase chain reaction (PCR) was performed. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a housekeeping gene, was used as a primer. In groups I and II, the HCC cells were completely filtered in all experiments. However, in groups III, IV, and V, the HCC cells were not completely filtered in a few of the repeated experiments, with the unfiltered rate of tumor cells being between 8% and 20%. In group VI, the HCC cells were not completely filtered in all the repeated experiments. In conclusion, the RCEZ1T filter markedly reduced the risk for reintroduction of HCC cells. However, at high HCC cell load the filter cannot completely remove all the tumor cells. Further studies are required to assess the impact in clinical settings. 相似文献
92.
Flow karyotypes and chromosomal DNA contents of genus Triticum species and rye (Secale cereale) 总被引:3,自引:0,他引:3
Jai-Heon Lee Youzhi Ma Toshiyuki Wako Lian Cheng Li Kee-Young Kim Seong-Whan Park Susumu Uchiyama Kiichi Fukui 《Chromosome research》2004,12(1):93-102
The flow cytometry and chromosome imaging method were jointly used for analyzing genome content and chromosomal DNA content of hexaploid wheat (AABBDD), hexaploid triticale (AABBRR), tetraploid wheat (AABB), and AA, BB, DD genome donors and RR genome rye. Their genome sizes were 34.4 pg, 40.9 pg, 26.2 pg, 12.1 pg, 13.7 pg, 10.5 pg, and 16.9 pg, respectively. The 2C nuclear DNA content of BB genome donor with 13.7 pg was the highest value among the other genome donors, AA or DD. The genome content of tetraploid wheat, unlike hexaploid wheat or hexaploid triticale, was larger than the sum of the genomes of AA and BB genome donors. The DNA content of each chromosome ranged from 1.22 pg in DD genome donor to 2.61 pg in rye. Each chromosome peak was divided into three to four groups. Only one chromosome was included in the highest chromosomal DNA peak in hexaploid wheat, tetraploid wheat, DD genome donor and rye but two chromosomes in AA, BB genome donors, and hexaploid triticale. Correlation between 2C nuclear DNA content and chromosome density volume was the highest value compared with the other chromosomal parameters of chromosome area, or chromosome length. 相似文献
93.
E Jung H-S Won S-K Kim J-Y Shim P R Lee A Kim J K Kim 《Ultrasound in obstetrics & gynecology》2006,27(5):562-565
Fetal thrombosis of the dural sinus is an extremely rare congenital cerebrovascular condition that is potentially fatal. We report a case of dural sinus thrombosis diagnosed by prenatal ultrasonography and fetal magnetic resonance imaging (MRI) in the second trimester. The thrombosis showed partial resolution during pregnancy and resolved spontaneously after birth without neurological complications. This is the first report of spontaneous postnatal resolution, and may provide helpful information on the natural history and prenatal counseling of fetal thrombosis of the dural sinus. 相似文献
94.
Identifying potential indicators of the quality of end-of-life cancer care from administrative data.
Craig C Earle Elyse R Park Bonnie Lai Jane C Weeks John Z Ayanian Susan Block 《Journal of clinical oncology》2003,21(6):1133-1138
PURPOSE: To explore potential indicators of the quality of end-of-life services for cancer patients that could be monitored using existing administrative data. METHODS: Quality indicators were identified and assessed by literature review for proposed indicators, focus groups with cancer patients and family members to assess candidate indicators and generate new ideas, and an expert panel ranking the meaningfulness and importance of each potential indicator using a modified Delphi approach. RESULTS: There were three major concepts of poor quality of end-of-life cancer care that could be examined using currently-available administrative data (such as Medicare claims): institution of new anticancer therapies or continuation of ongoing treatments very near death; a high number of emergency room visits, inpatient hospital admissions, or intensive care unit days near the end of life; and a high proportion of patients never enrolled in hospice, only admitted in the last few days of life, or dying in an acute-care setting. Concepts such as access to psychosocial and other multidisciplinary services and pain and symptom control are important and may eventually be feasible, but they cannot currently be applied in most data systems. Indicators based on limiting the use of treatments with low probability of benefit or indicators based on economic efficiency were not acceptable to patients, family members, or physicians. CONCLUSION: Several promising claims-based quality indicators were identified that, if found to be valid and reliable within data systems, could be useful in identifying health-care systems in need of improving end-of-life services. 相似文献
95.
Jungsun Park MD PhD Naomi Hisanaga MD Yangho Kim MD MPH 《American journal of industrial medicine》2009,52(8):625-632
Many corporations move their manufacturing facilities or technologies from developed to developing countries. Stringent regulations have made it costly for industries to operate in developed, industrialized countries. In addition, labor costs are high in these countries, and there is increasing awareness among the general public of the health risks associated with industry. The relocation of hazardous industries to developing countries is driven by economic considerations: high unemployment, a cheaper labor force, lack of regulation, and poor enforcement of any existing regulations make certain countries attractive to business. The transfer of certain industries from Japan to Korea has also brought both documented occupational diseases and a new occupational disease caused by chemicals without established toxicities. Typical examples of documented occupational diseases are carbon disulfide poisoning in the rayon manufacturing industry, bladder cancer in the benzidine industry, and mesothelioma in the asbestos industry. A new occupational disease due to a chemical without established toxicities is 2‐bromopropane poisoning. These examples suggest that counter‐measures are needed to prevent the transfer of occupational health problems from a developed to a developing country. Corporate social responsibility should be emphasized, close inter‐governmental collaboration is necessary and cooperation among non‐governmental organizations is helpful. Am. J. Ind. Med. 52:625–632, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
96.
97.
Kiran Chang Mona Sarkiss Kyoung Sook Won Joseph Swafford Lyle Broemeling Isis Gayed 《Journal of nuclear medicine》2007,48(3):344-348
Cancer patients frequently have anemia or an altered coagulation state that may affect their risk stratification for perioperative cardiac events. We performed this study to investigate the incidence of perioperative cardiac events in cancer patients who had abnormal stress myocardial perfusion imaging (MPI) results versus cancer patients with normal MPI results. METHODS: We included 394 consecutive cancer patients with normal (n = 201) or abnormal (n = 193) results on MPI studies performed for preoperative risk stratification. MPI was performed within 6 mo before each patient's scheduled operation. All the patients had surgical procedures requiring general anesthesia, except for 18 who had endoscopic or colonoscopic procedures. We retrospectively reviewed their data for the incidence of major cardiac events intraoperatively and for 1 mo postoperatively. We collected data on their cancer type, risk factors for coronary artery disease, MPI findings, risk of operation, and intraoperative or postoperative major cardiac events, which included death, myocardial infarction (MI), and congestive heart failure (CHF). RESULTS: The patients with abnormal MPI results included 97 with ischemia, 80 with scarring, and 16 with mixed scarring and ischemia. The mean left ventricular ejection fraction and end-diastolic volume were 63.8% +/- 9.8% and 82.0 +/- 53.5 mL in the normal MPI group versus 52.1% +/- 13.1% and 118.1 +/- 53.4 mL in the abnormal-MPI group (P < 0.001). There were 9 major intraoperative or postoperative cardiac events (4.7%) in the patients with abnormal MPI results and none in the patients with normal MPI results (P = 0.001). These major events consisted of 3 deaths, 2 acute MIs, 1 non-Q-wave MI, and 3 cases of CHF. Four of these patients had only scarring on their MPI studies, 3 had ischemia, and 2 had scarring and ischemia. CONCLUSION: Normal MPI results have a high negative predictive value for perioperative cardiac events in cancer patients. Abnormal MPI results, whether demonstrating scarring or ischemia, should prompt appropriate perioperative management in patients with cancer to minimize major cardiac events. 相似文献
98.
99.
100.
Mandeep R. Mehra Patricia A. Uber Ananth Prasad Robert L. Scott Myung H. Park 《American journal of transplantation》2005,5(5):1137-1140
To identify tobacco recidivism among 86 heart transplant recipients who were smokers but demonstrated compliance with a smoking cessation program pre-transplant, we used a questionnaire and randomly tested urine for nicotine and its by-products. In 36 patients, we also evaluated circulating levels of HS-CRP, homocysteine and MPV. Twenty-eight (32.5%) of 86 patients met our definition for tobacco exposure. In this cohort, 28 (32.5%) of 86 patients met our definition for tobacco exposure. Of these 28, 12 patients self-reported tobacco use and demonstrated biochemical verification; 14 patients demonstrated only biochemical evidence of significant tobacco exposure; 2 patients self-reported tobacco use but did not demonstrate biochemical positivity. Smoking cessation within 6 months of transplantation (r = 0.52) and time post-transplantation (r = 0.43) were independent predictors for recidivism of tobacco use, p < 0.01. No differences in HS-CRP, homocysteine and MPV levels were noted among the groups. Our investigation demonstrates a high rate of tobacco recidivism among heart transplant recipients, yet few admit to it. The adverse effects of tobacco do not appear to be directly modulated by an effect on athero-thrombotic risk markers. 相似文献