首页 | 本学科首页   官方微博 | 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   16520篇
  免费   1044篇
  国内免费   79篇
耳鼻咽喉   132篇
儿科学   425篇
妇产科学   418篇
基础医学   2617篇
口腔科学   661篇
临床医学   1375篇
内科学   3664篇
皮肤病学   341篇
神经病学   1959篇
特种医学   450篇
外科学   1455篇
综合类   41篇
一般理论   5篇
预防医学   1012篇
眼科学   274篇
药学   1349篇
中国医学   57篇
肿瘤学   1408篇
  2024年   18篇
  2023年   170篇
  2022年   393篇
  2021年   591篇
  2020年   360篇
  2019年   477篇
  2018年   574篇
  2017年   451篇
  2016年   522篇
  2015年   649篇
  2014年   738篇
  2013年   936篇
  2012年   1469篇
  2011年   1563篇
  2010年   775篇
  2009年   742篇
  2008年   1166篇
  2007年   1087篇
  2006年   1015篇
  2005年   925篇
  2004年   829篇
  2003年   753篇
  2002年   641篇
  2001年   75篇
  2000年   54篇
  1999年   69篇
  1998年   105篇
  1997年   94篇
  1996年   60篇
  1995年   57篇
  1994年   42篇
  1993年   30篇
  1992年   19篇
  1991年   16篇
  1990年   12篇
  1989年   23篇
  1988年   15篇
  1987年   22篇
  1986年   14篇
  1985年   14篇
  1984年   11篇
  1983年   15篇
  1982年   13篇
  1981年   12篇
  1980年   5篇
  1979年   5篇
  1978年   4篇
  1975年   3篇
  1973年   6篇
  1961年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Violence against women is frequent, and has serious consequences for their physical and mental health. Until now, a common response of health services and professionals to victims has been the denial of the violence. The aims of this study were to estimate the prevalence of present and past violence among women attending social and health services in Trieste (Italy) for any reasons, and to evaluate the feasibility of asking them about violence. Five public health care facilities were involved: a hospital-based Emergency Department, two "Consultorio Familiare", and two community-based Social service centers. The final sample consisted of 510 women; the response rate among eligible women was 76% across all facilities. The study revealed a high prevalence of different kinds of violence, mostly perpetrated by men well known to the victim. Among the women interviewed, 10.2% had experienced physical/sexual violence in the last 12 months, regardless of perpetrator. Violence by a male partner or former partner, occurred in 6.4% of women; by other relatives, 1.6% of women; and by "other" persons 3.3% of women. The results demonstrated the feasibility of "asking about violence" in all cases; moreover, those women who had been abused were often eager to talk about it. A systematic approach to the issue of violence is a necessary condition for responding appropriately to the needs of women who have experienced or are experiencing violence. Nevertheless, to avoid the replication of a common bias against victims of violence, health and social personnel should be appropriately trained before "asking all cases" becomes a policy within health and social services.  相似文献   
952.
The efficacy of candidate AIDS vaccines to mediate protection against viral infection and pathogenesis is evaluated, at a preclinical stage, in animal models. One model that is favored because the infecting virus is closely related to HIV-1 and because of the rapidity of pathogenic outcomes is the infection of Old World monkeys by simian-human immunodeficiency virus (SHIV) chimerae. We investigated the basis for the depletion of CD4(+) T lymphocytes in a SHIV-macaque model. Molecularly cloned SHIVs, SHIV-89.6 and SHIV-KB9, differ in the ability to cause CD4(+) T-cell loss at a given level of virus replication in monkeys. The envelope glycoproteins of the pathogenic SHIV-KB9 mediate membrane-fusion in cultured T lymphocytes more efficiently than the envelope glycoproteins of the non-pathogenic SHIV-89.6. The minimal envelope glycoprotein region that specifies this increase in membrane-fusing capacity was sufficient to convert SHIV-89.6 into a virus that causes profound CD4(+) T-cell depletion in monkeys. Conversely, two single amino acid changes that decrease the membrane-fusing ability of the SHIV-KB9 envelope glycoproteins also attenuated the CD4(+) T-cell destruction that accompanied a given level of virus replication in SHIV-infected monkeys. Thus, the ability of the HIV-1 envelope glycoproteins to fuse membranes, which has been implicated in the induction of viral cytopathic effects in vitro, contributes to the capacity of the pathogenic SHIV to deplete CD4(+) T lymphocytes in vivo.  相似文献   
953.
954.
955.
The aim of this study was to extend our previous observations on the soy modulation of biochemical parameters in 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumors, by simultaneously investigating the expression of estrogen receptor-alpha (ERalpha), estrogen receptor-beta (ERbeta), progesterone receptor (PR), apoptosis, neu, and markers of cell proliferation, such as proliferating cell nuclear antigen (PCNA) by immunohistochemistry. The percentage of ERalpha positive tumors was 65.8% in masses from control animals, and significantly dropped to 36.8% in tumors from soy treated rats (P=0.010). The percentage of ERbeta positive tumors was 70.3% in masses from control animals vs. 50.0% in tumors from soy exposed animals (P=0.066). Moreover, the percentage of cases which were both ERalpha and ERbeta positive was significantly lower (17.6%) in soy treated than in control animals (51.3%) (P=0.006). The percentage of PR positive tumors was 34.2% in control animals vs. 2.6% in tumors from soy treated rats (P=0.0006). There were no statistically significant differences in the percentage of tumors positively stained for neu, apoptosis, or PCNA, in control vs. soy treated rats. However, when analyzing the reciprocal correlation among the different biochemical parameters we showed that, in treated animals, the majority of ERalpha positive tumors (91.7%) were also PCNA positive (P=0.036). The median percentage of PCNA positivity was significantly higher in ERalpha positive than in ERalpha negative tumors (25 vs. 5%) (P=0.0031). Moreover, an association was found between PCNA and neu status since all neu positive tumors were also PCNA positive (P=0.011).  相似文献   
956.
Gene expression in epithelial ovarian carcinoma   总被引:1,自引:0,他引:1  
Matei D  Graeber TG  Baldwin RL  Karlan BY  Rao J  Chang DD 《Oncogene》2002,21(41):6289-6298
  相似文献   
957.
958.
959.
PURPOSE: Compared to photon irradiation, carbon ions provide physical and biologic advantages that may be exploited in chordomas and chondrosarcomas. METHODS AND MATERIALS: Between August 1998 and December 2000, 37 patients with chordomas (n = 24) and chondrosarcomas (n = 13) were treated with carbon ion radiotherapy within a Phase I/II trial. Tumor conformal application of carbon ion beams was realized by intensity-controlled raster scanning with pulse-to-pulse energy variation. Three-dimensional treatment planning included biologic plan optimization. The median tumor dose was 60 GyE (GyE = Gy x relative biologic effectiveness). RESULTS: The mean follow-up was 13 months. The local control rate after 1 and 2 years was 96% and 90%, respectively. We observed 2 recurrences outside the gross tumor volume in patients with chordomas. Progression-free survival was 100% for chondrosarcomas and 83% for chordomas at 2 years. Partial remission after carbon ion radiotherapy was observed in 6 patients. Treatment toxicity was mild. CONCLUSION: These are the first data demonstrating the clinical feasibility, safety, and effectiveness of scanning beam delivery of ion beams in patients with skull base tumors. The preliminary results in patients with skull base chordomas and low-grade chondrosarcomas are encouraging, although the follow-up was too short to draw definite conclusions concerning outcome. In the absence of major toxicity, dose escalation might be considered.  相似文献   
960.
Terribile D  Palumbo F  Nardone L 《Rays》2002,27(4):291-294
Sentinel lymph node biopsy was shown to be an accurate procedure in the study of axillary lymph nodes; it allowed a marked decrease in surgery-related morbidity of breast cancer and axillary dissection could be avoided. Other parameters as molecular markers, nuclear grading, patient age, tumor size, are not able to predict the axillary lymph node status and consequent local therapeutic approach similar to those provided by sentinel lymph node biopsy. The extent of sentinel lymph node metastatic involvement, the extracapsular spread, the size of primary tumor and peritumoral lymphatic/vascular infiltration are the four characteristics shown to be significant, if considered in association and not separately as predictors of the extent of axillary involvement in presence of a positive sentinel lymph node. However, so far, specific studies did not confirm concordant and reproducible results. Therefore, apart from controlled studies, axillary dissection is always required in presence of a metastatic sentinel lymph node.  相似文献   
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