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   581502篇
  免费   41280篇
  国内免费   28578篇
耳鼻咽喉   4220篇
儿科学   11804篇
妇产科学   7705篇
基础医学   62453篇
口腔科学   8534篇
临床医学   69325篇
内科学   84153篇
皮肤病学   5281篇
神经病学   36016篇
特种医学   24125篇
外国民族医学   244篇
外科学   65295篇
综合类   80580篇
现状与发展   95篇
一般理论   32篇
预防医学   47047篇
眼科学   14546篇
药学   54411篇
  474篇
中国医学   27543篇
肿瘤学   47477篇
  2024年   451篇
  2023年   5564篇
  2022年   9688篇
  2021年   17922篇
  2020年   15811篇
  2019年   13197篇
  2018年   34430篇
  2017年   29508篇
  2016年   30683篇
  2015年   19716篇
  2014年   24338篇
  2013年   22035篇
  2012年   38312篇
  2011年   55944篇
  2010年   41920篇
  2009年   30484篇
  2008年   42813篇
  2007年   44935篇
  2006年   23436篇
  2005年   23969篇
  2004年   17650篇
  2003年   18148篇
  2002年   13866篇
  2001年   10202篇
  2000年   10180篇
  1999年   10147篇
  1998年   6389篇
  1997年   6322篇
  1996年   4826篇
  1995年   4562篇
  1994年   3866篇
  1993年   2506篇
  1992年   2994篇
  1991年   2662篇
  1990年   2285篇
  1989年   1945篇
  1988年   1610篇
  1987年   1408篇
  1986年   1184篇
  1985年   858篇
  1984年   482篇
  1983年   360篇
  1982年   201篇
  1981年   212篇
  1980年   178篇
  1979年   188篇
  1978年   81篇
  1974年   61篇
  1938年   62篇
  1932年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Many environmental risk factors for hepatobiliary cancers are known but whether they are associated with specific cancer types is unclear. We present here a novel approach of assessing standardized incidence ratios (SIRs) of previously diagnosed comorbidities for hepatocellular carcinoma (HCC), gallbladder cancer (GBC), cholangiocarcinoma (CCA) and ampullary cancer. The 13 comorbidities included alcohol and nonalcohol related liver disease, chronic obstructive pulmonary disease, gallstone disease, viral and other kinds of hepatitis, infection of bile ducts, hepatic and other autoimmune diseases, obesity and diabetes. Patients were identified from the Swedish Inpatient Register from 1987 to 2018, and their cancers were followed from 1997 onwards. SIRs for HCC were 80 to 100 in men and women diagnosed with hepatitis C virus and they were also >10 in patients diagnosed with hepatitis B virus, other kind of hepatitis, hepatic autoimmune disease and nonalcohol related liver disease. Many of these risks, as well as alcohol related liver disease, were either specific to HCC or were shared with intrahepatic CCA. For GBC, CCA and ampullary cancer infection of bile ducts was the main risk factor. Gallstone disease, nonhepatic autoimmune diseases and diabetes were associated with all hepatobiliary cancers. The limitations of the study include inability to cover some rare risk factors and limited follow-up time. Many of the considered comorbidities are characterized by chronic inflammation and/or overt immune disturbance in autoimmune diseases. The results suggest that local chronic inflammation and a related immune disturbance is the carcinogenic trigger for all these cancers.  相似文献   
2.
DNA损伤是衰老相关疾病领域的研究热点, 可引起细胞周期停滞、凋亡, 加快个体衰老速度、增加衰老相关疾病的患病风险。本文将从细胞衰老和个体衰老两个层面阐述其与衰老之间的研究进展, 并综述其与衰老常见相关疾病(肿瘤、心血管疾病、阿尔茨海默病)及早衰综合征的关系, 为抗衰老研究和临床干预衰老相关疾病提供理论依据。  相似文献   
3.
4.
A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on modal energy coefficients is proposed to detect troubled cells, where discontinuities exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR method. Numerical investigations show that the proposed subcell limiting strategy on unstructured quadrilateral meshes is robust in shock-capturing.  相似文献   
5.
目的 评价多功能套针浮刺疗法对神经根型颈椎病的临床疗效。方法 选取256例神经根型颈椎病患者,按随机数字表法分为观察组与对照组各128例。观察组应用多功能套针浮刺疗法进行干预,对照组为常规针刺治疗。两组患者均治疗7天。分别于治疗前后观察两组患者的简化McGill疼痛问卷(SF-MPQ)、国际标准颈椎功能障碍指数(NDI)和田中靖久颈椎病症状20分法量表评分,并于治疗结束后3个月观察复发率。结果 两组患者治疗后的SF-MPQ量表评分、NDI量表评分及田中靖久颈椎病症状20分法评分与治疗前相比均有改善(P<0.05),且观察组优于对照组(P<0.05);两组患者于治疗后3个月随访,SF-MPQ量表评分与治疗后相比均有改善,且观察组优于对照组(P<0.05);观察组临床疗效总有效率为96.88%,愈显率为81.25%;对照组总有效率为78.13%,愈显率为46.88%,观察组优于对照组(P<0.05)。结论 应用多功能套针浮刺疗法治疗神经根型颈椎病临床疗效显著,见效较快,可有效降低其复发率,且作用稳定,效果持久,值得临床推广应用。  相似文献   
6.
目的分析江苏省启东市1972—2016年胃癌死亡流行特征。方法收集启东市1972—2016年恶性肿瘤死亡登记数据库及历年人口资料, 计算死亡率、中国人口标化率(中标率)、世界人口标化率(世标率)、35~64岁截缩率、0~74岁累积死亡率、累积死亡风险、变化百分比、死亡率年均变化百分比。结果 1972—2016年启东市胃癌死亡例数为15 863例, 占全部恶性肿瘤死亡例数的16.04%, 胃癌死亡率为31.37/10万, 中标率为12.97/10万, 世标率为21.39/10万, 35~64岁截缩死亡率为28.86/10万, 0~74岁累积死亡率为2.54%, 胃癌死亡累积风险为2.51%。男性死亡10 114例, 男性死亡率、中标率、世标率分别为40.53/10万、17.98/10万和30.13/10万;女性死亡5 749例, 女性死亡率、中标率、世标率分别为22.45/10万、8.52/10万和13.92/10万。25岁以下各年龄组的死亡率<1/10万, 死亡率随年龄的增长而升高, 50~岁组达到并超过人群的平均死亡率水平, 80~岁组达到死亡高峰。1972—2016年间胃癌死...  相似文献   
7.
8.
9.
10.
Information regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on cervical cancer in mainland China is lacking. We explored its impact on the hospital attendance of patients with primary cervical cancer. We included 1918 patients with primary cervical cancer who initially attended Harbin Medical University Cancer Hospital between January 23, 2019, and January 23, 2021. Attendance decreased by 31%, from 1135 in 2019 to 783 in 2020, mainly from January to June (𝜒2 = 73.362, P < .001). The percentage of patients detected by screening decreased from 12.1% in January-June 2019 to 5.8% in January-June 2020 (𝜒2 = 7.187, P = .007). Patients with stage I accounted for 28.4% in 2020 significantly lower than 36.6% in 2019 (𝜒2 = 14.085, P < .001), and patients with stage III accounted for 27.1% in 2020 significantly higher than 20.5% in 2019 (𝜒2 = 11.145, P < .001). Waiting time for treatment was extended from 8 days (median) in January-June and July-December 2019 to 16 days in January-June (𝜒2 = 74.674, P < .001) and 12 days in July-December 2020 (𝜒2 = 37.916, P < .001). Of the 179 patients who delayed treatment, 164 (91.6%) were for the reasons of the healthcare providers. Compared to 2019, the number of patients in Harbin or non-Harbin in Heilongjiang Province and outside the province decreased, and cross-regional medical treatment has been hindered. The COVID-19 pandemic has negatively impacted cervical cancer patient attendance at the initial phase. These results are solid evidence that a strategy and mechanism for the effective attendance of cervical cancer patients in response to public health emergencies is urgently needed.  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