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   2046篇
  免费   220篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   104篇
妇产科学   28篇
基础医学   268篇
口腔科学   39篇
临床医学   185篇
内科学   536篇
皮肤病学   28篇
神经病学   92篇
特种医学   300篇
外科学   125篇
综合类   54篇
预防医学   163篇
眼科学   161篇
药学   115篇
中国医学   1篇
肿瘤学   69篇
  2021年   16篇
  2019年   15篇
  2018年   21篇
  2017年   26篇
  2016年   22篇
  2015年   27篇
  2014年   37篇
  2013年   48篇
  2012年   51篇
  2011年   43篇
  2010年   64篇
  2009年   64篇
  2008年   77篇
  2007年   80篇
  2006年   86篇
  2005年   69篇
  2004年   77篇
  2003年   75篇
  2002年   51篇
  2001年   47篇
  2000年   38篇
  1999年   45篇
  1998年   63篇
  1997年   81篇
  1996年   63篇
  1995年   56篇
  1994年   65篇
  1993年   59篇
  1992年   46篇
  1991年   42篇
  1990年   51篇
  1989年   56篇
  1988年   60篇
  1987年   47篇
  1986年   56篇
  1985年   47篇
  1984年   20篇
  1983年   32篇
  1982年   23篇
  1981年   31篇
  1980年   31篇
  1979年   17篇
  1978年   21篇
  1977年   30篇
  1976年   27篇
  1975年   31篇
  1973年   19篇
  1972年   16篇
  1971年   15篇
  1970年   14篇
排序方式: 共有2270条查询结果,搜索用时 15 毫秒
91.
Delay in hematologic recovery after bone marrow transplantation (BMT) can extend and amplify the risks of infection and hemorrhage, compromise patients' survival, and increase the duration and cost of hospitalization. Because current studies suggest that granulocyte- macrophage (GM) colony-stimulating factor (CSF) may potentiate the sensitivity of hematopoietic progenitor cells to G-CSF, we performed a prospective, randomized trial comparing GM-CSF (250 micrograms/m2/d x 14 days) versus sequential GM-CSF x 7 days followed by G-CSF (5 micrograms/kg/d x 7 days) as treatment for primary or secondary graft failure after BMT. Eligibility criteria included failure to achieve a white blood cell (WBC) count > or = 100/microL by day +21 or > or = 300/microL by day +28, no absolute neutrophil count (ANC) > or = 200/microL by day +28, or secondary sustained neutropenia after initial engraftment. Forty-seven patients were enrolled: 23 received GM-CSF (10 unrelated, 8 related allogeneic, and 5 autologous), and 24 received GM- CSF followed by G-CSF (12 unrelated, 7 related allogeneic, and 5 autologous). For patients receiving GM-CSF alone, neutrophil recovery (ANC > or = 500/microL) occurred between 2 and 61 days (median, 8 days) after therapy, while those receiving GM-CSF+G-CSF recovered at a similar rate of 1 to 36 days (median, 6 days; P = .39). Recovery to red blood cell (RBC) transfusion independence was slow, occurring 6 to 250 days (median, 35 days) after enrollment with no significant difference between the two treatment groups (GM-CSF: median, 30 days; GM-CSF+G- CSF; median, 42 days; P = .24). Similarly, platelet transfusion independence was delayed until 4 to 249 days (median, 32 days) after enrollment, with no difference between the two treatment groups (GM- CSF: median, 28 days; GM-CSF+G-CSF: median, 42 days; P = .38). Recovery times were not different between patients with unrelated donors and those with related donors or autologous transplant recipients. Survival at 100 days after enrollment was superior after treatment with GM-CSF alone. Only 1 of 23 patients treated with GM-CSF died versus 7 of 24 treated with GM-CSF+G-CSF who died 16 to 84 days (median, 38 days) after enrollment, yielding Kaplan-Meier 100-day survival estimates of 96% +/- 8% for GM-CSF versus 71% +/- 18% for GM-CSF+G-CSF (P = .026). These data suggest that sequential growth factor therapy with GM-CSF followed by G-CSF offers no advantage over GM-CSF alone in accelerating trilineage hematopoiesis or preventing lethal complications in patients with poor graft function after BMT.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
92.
Elimination of neoplastic B cell populations from autologous bone marrow grafts also removes normal B lymphocytes. This is potentially hazardous for the reconstitution of the immune system in patients undergoing high-dose chemotherapy and total body irradiation followed by autologous marrow rescue. Five pediatric patients with B cell non- Hodgkin's lymphoma in first remission undergoing such a regimen were studied. They received bone marrow pretreated with anti-Y 29/55 monoclonal antibody and complement. B and T lymphocyte subpopulations reached normal levels within 6 months after autologous bone marrow transplantation (ABMT), and serum immunoglobulin levels became normal within 4 to 9 months. Vaccination with diphtheria and tetanus toxoid, trivalent poliomyelitis vaccine of the Salk type, and pneumococcal capsular antigens (38 to 54 months after transplantation) gave rise to specific antibody production. ABO isoagglutinins could be demonstrated in all patients. The response pattern was similar to that of patients who received unmanipulated autologous bone marrow. It is concluded that ex vivo anti-Y 29/55 depletion of the marrow graft does not induce relevant disturbances of humoral immune functions.  相似文献   
93.
The alpha-fetoprotein gene (Afp) is a member of a multigenic family that comprises the related genes encoding albumin, alpha-albumin, and vitamin D binding protein. The biological role of this major embryonic serum protein is unknown although numerous speculations have been made. We have used gene targeting to show that AFP is not required for embryonic development. AFP null embryos develop normally, and individually transplanted homozygous embryos can develop in an AFP-deficient microenvironment. Whereas mutant homozygous adult males are viable and fertile, AFP null females are infertile. Our analyses of these mice indicate that the defect is caused by a dysfunction of the hypothalamic/pituitary system, leading to anovulation.  相似文献   
94.
95.
96.
Genome sequencing has revolutionized the way in which we approach biological research from fundamental molecular biology to ecology and epidemiology. In the last 10 years the field of genomics has changed enormously as technology has improved and the tools for genomic sequencing have moved out of a few dedicated centers and now can be performed on bench-top instruments. In this review we will cover some of the key discoveries that were catalyzed by some of the first genome projects and discuss how this field is developing, what the new challenges are and how this may impact on research in the near future.  相似文献   
97.
Serum and liver samples collected monthly, during 2005, from healthy wild rabbits at a site in Pitroddie, Scotland, were analysed by ELISA and RT-PCR sequencing. Sera collected in January and February had high antibody titres against RHDV. However, during the rabbit breeding season average antibody titres were lower but increased again as the year progressed. Between March and August, RHDV-specific RNA was detected in healthy rabbits spanning a wide range of age and antibody titres. Importantly, two virus lineages were identified; a novel widely divergent strain, recovered between March and August, and a strain related to UK epidemic strains, was recovered between May and July from juvenile rabbits. We propose that a non-virulent widely divergent strain of RHDV circulated asymptomatically amongst the wild rabbits potentially inducing immunity against the introduced epidemic strain that predominantly causes high fatality rates in young immunologically naïve rabbits.  相似文献   
98.
We evaluated the association of body mass index (BMI) with migraine and migraine specifics in a cross-sectional study of 63 467 women aged ≥ 45 years, of whom 12 613 (19.9%) reported any history of migraine and 9195 had active migraine. Compared with women without migraine and a BMI < 23 kg/m2, women with a BMI ≥ 35 kg/m2 had adjusted odds ratios (ORs) (95% confidence intervals) of 1.03 (0.95, 1.12) for any history of migraine. Findings were similar for active migraineurs. Women with a BMI of ≥ 35 kg/m2 had increased risk for low and high migraine frequency, with the highest estimate for women who reported daily migraine. Compared with women with the lowest associated risk (migraine frequency < 6 times/year; BMI between 27.0 and 29.9 kg/m2), women with a BMI ≥ 35 kg/m2 had an OR of daily migraine of 3.11 (1.12, 8.67). Among the women with active migraine, a BMI ≥ 35 kg/m2 was associated with increased risk of phonophobia and photophobia and decreased risk of a unilateral pain characteristic and migraine aura. Our data confirm previous findings that the association between BMI with migraine is limited to migraine frequency and specific migraine features.  相似文献   
99.
100.
The medial collateral ligament (MCL) is the most commonly injured ligament of the knee. There is a spectrum of injury severity, and injuries may be acute or chronic. The MCL is also frequently injured in conjunction with other knee structures. Clinical evaluation of the knee is important to assess the degree of surgical acuity, but magnetic resonance imaging can provide details about the injury that may not be obvious clinically. In addition to injury, MCL bursitis can occur and may be treated with needle aspiration and corticosteroid injection. This review article covers the anatomy and biomechanics of the MCL, its injury patterns and approach to management, and MCL bursitis.  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