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   24756篇
  免费   2492篇
  国内免费   27篇
耳鼻咽喉   225篇
儿科学   704篇
妇产科学   590篇
基础医学   3387篇
口腔科学   605篇
临床医学   2912篇
内科学   5131篇
皮肤病学   352篇
神经病学   2382篇
特种医学   789篇
外科学   3223篇
综合类   591篇
一般理论   15篇
预防医学   2583篇
眼科学   455篇
药学   2121篇
  1篇
中国医学   29篇
肿瘤学   1180篇
  2021年   364篇
  2020年   202篇
  2019年   351篇
  2018年   408篇
  2017年   331篇
  2016年   316篇
  2015年   372篇
  2014年   519篇
  2013年   773篇
  2012年   1122篇
  2011年   1168篇
  2010年   670篇
  2009年   565篇
  2008年   1006篇
  2007年   1174篇
  2006年   1090篇
  2005年   1129篇
  2004年   1004篇
  2003年   1075篇
  2002年   959篇
  2001年   699篇
  2000年   693篇
  1999年   599篇
  1998年   287篇
  1997年   233篇
  1996年   213篇
  1995年   254篇
  1994年   229篇
  1992年   523篇
  1991年   482篇
  1990年   462篇
  1989年   461篇
  1988年   420篇
  1987年   422篇
  1986年   375篇
  1985年   438篇
  1984年   376篇
  1983年   296篇
  1982年   287篇
  1981年   235篇
  1980年   239篇
  1979年   346篇
  1978年   294篇
  1977年   209篇
  1976年   244篇
  1975年   214篇
  1974年   272篇
  1973年   284篇
  1972年   232篇
  1971年   213篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
Copper radionuclides and radiopharmaceuticals in nuclear medicine   总被引:4,自引:0,他引:4  
The chemistry, radiochemistry, radiobiology, and radiopharmacology of radiopharmaceuticals containing copper radionuclides are reviewed. Copper radionuclides offer application in positron emission tomography, targeted radiotherapy, and single photon imaging. The chemistry of copper is relatively simple and well-suited to radiopharmaceutical application. Current radiopharmaceuticals include biomolecules labelled via bifunctional chelators primarily based on cyclic polyaminocarboxylates and polyamines, and pyruvaldehyde-bis(N4-methylthiosemicarbazone) (PTSM) and its analogues. The chemistry of copper, of which only a fraction has yet been exploited, is likely to be applied more fully in the future.  相似文献   
83.
The authors report nine cases of endodrainage retinotomy site complications that occurred after vitreous surgery for complicated retinal detachments (RDs). Postoperative subretinal neovascularization developed in four eyes at the retinotomy drainage site. In two eyes, postoperative proliferation at a posteriorly placed endodrainage site created traction macular detachments. Redetachment due to retinotomy opening caused by postoperative drainage site proliferation developed in three eyes. The retinas of all nine eyes were eventually reattached, and vision improved from the preoperative level. These complications are related to retinal pigment epithelium and/or Bruch's membrane damage during internal subretinal fluid drainage and retinotomy endolaser photocoagulation. Careful evaluation of extrusion instruments, drainage techniques, retinotomy placement, and subsequent endolaser treatment is necessary to minimize these complications.  相似文献   
84.
85.
Between November 1967 and December 1994, 242 patients with gestational trophoblastic disease (GTD) were treated with chemotherapy by the Gynecology Service of Memorial Hospital. Eighty-seven of the patients (35.9%) underwent at least one major operation during the course of their illness. Twenty-six patients underwent two major operations, and in five patients, three major operations were performed, for a total of 118 procedures. The most frequent procedures were: hysterectomy, 56 (47.4%); hysterotomy, 15 (12.7%); thoracotomy, 13 (11%); and craniotomy, 5 (4.2%). Twenty-nine additional procedures ranging in complexity from oophorectomy to segmental liver resection were also performed. Twenty-nine operations (24.5%) were considered to be beyond the scope of most gynecologic surgeons. The overall complete remission rate for 242 patients was 90.4%. The rate for patients who underwent a major surgical procedure was 79.3% compared to 96.7% for patients whose treatment was with chemotherapy alone.
The data demonstrate that the integration of surgery in the management of GTD patients often requires a multidisciplinary approach that in many cases can best be achieved at specialized treatment centers.  相似文献   
86.
87.
OBJECTIVE: To analyze treatment and survival of a large cohort of patients with retroperitoneal soft-tissue sarcomas (STS) treated and prospectively followed at a single institution. SUMMARY BACKGROUND DATA: Retroperitoneal STS are relatively uncommon and constitute a difficult management problem. Although surgical resection is often difficult or impossible, current chemotherapy is not effective and radiation is limited by toxicity to adjacent structures. Thus, complete surgical resection remains the most effective modality for selected primary and recurrent disease. METHODS: Five hundred patients with retroperitoneal STS were admitted and treated between July 1, 1982, and September 30, 1997, and prospectively followed. Patient, tumor, and treatment variables were analyzed for disease-specific and disease-free survival. Survival was determined with the Kaplan-Meier method. Statistical significance was evaluated using the logrank test for univariate influence and Cox model stepwise regression for multivariate influence. RESULTS: Two hundred seventy-eight patients (56%) had primary disease and 222 (44%) recurrent disease. Median follow-up was 28 months (range 1 to 172 months), 40 months for survivors. Median survival was 72 months for patients with primary disease, 28 months for those with local recurrence, and 10 months for those with metastasis. For patients with primary or locally recurrent tumors, unresectable disease, incomplete resection, and high-grade tumors significantly reduced survival time. CONCLUSIONS: In this study of patients with retroperitoneal STS, stage at presentation, high histologic grade, unresectable primary tumor, and positive gross margin are strongly associated with the tumor mortality rate. Patients approached with curative intent should undergo aggressive attempts at complete surgical resection. Incomplete resection should be undertaken only for symptom relief.  相似文献   
88.
89.
Necrotizing soft-tissue infections have been widely recognized for over a century, but they remain a challenging problem in clinical infectious disease. Patterns of disease are clearly apparent, but most are polymicrobial and derive increased virulence from synergy between bacteria. Early recognition and prompt surgical drainage are the keys to successful treatment. Edema extending beyond the area of erythema, skin vesicles, crepitus or air in the subcutaneous tissues, and absence of lymphangitis and lymphadenitis are markers of necrotizing infections, particularly when they occur in patients with serious underlying disease. Empiric broad-spectrum antibiotics, prophylactic heparin, and nutritional therapy are important adjuncts to aggressive "stepwise" surgical debridement. A knowledge of patterns of disease can aid in fine-tuning treatment to decrease morbidity.  相似文献   
90.
Improper implant angulation is one of the most difficult problems to overcome in the fabrication of implant-supported and implant-retained restorations. Several techniques using the "UCLA" abutment have been developed to solve these problems. The creation of large screw-access holes for moderate angulation and the fabrication of telescopic copings and overlay castings for severe angulation problems are discussed.  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