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   3209532篇
  免费   229567篇
  国内免费   8658篇
耳鼻咽喉   43202篇
儿科学   107231篇
妇产科学   88607篇
基础医学   453619篇
口腔科学   89185篇
临床医学   293187篇
内科学   627490篇
皮肤病学   75541篇
神经病学   262171篇
特种医学   123352篇
外国民族医学   1009篇
外科学   478011篇
综合类   67441篇
现状与发展   5篇
一般理论   1265篇
预防医学   248425篇
眼科学   72359篇
药学   233988篇
  11篇
中国医学   6561篇
肿瘤学   175097篇
  2019年   24999篇
  2018年   35414篇
  2017年   27240篇
  2016年   31349篇
  2015年   35309篇
  2014年   48599篇
  2013年   73726篇
  2012年   97672篇
  2011年   103434篇
  2010年   62215篇
  2009年   59380篇
  2008年   96715篇
  2007年   102574篇
  2006年   104535篇
  2005年   100174篇
  2004年   96890篇
  2003年   93542篇
  2002年   90189篇
  2001年   152906篇
  2000年   156701篇
  1999年   132191篇
  1998年   38011篇
  1997年   33902篇
  1996年   33960篇
  1995年   32910篇
  1994年   30323篇
  1993年   28270篇
  1992年   103576篇
  1991年   100062篇
  1990年   97270篇
  1989年   93936篇
  1988年   85870篇
  1987年   84678篇
  1986年   79286篇
  1985年   75940篇
  1984年   56632篇
  1983年   47994篇
  1982年   28554篇
  1981年   25578篇
  1979年   50462篇
  1978年   35873篇
  1977年   30408篇
  1976年   28347篇
  1975年   30080篇
  1974年   35817篇
  1973年   34126篇
  1972年   31765篇
  1971年   29576篇
  1970年   27250篇
  1969年   25993篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Ivalon (polyvinyl alcohol) is a commonly used embolic agent, generally considered to be permanent. In a patient with the carcinoid syndrome, embolization of hepatic metastases with Ivalon failed to produce permanent occlusion, and recurrent tumor was supplied by many of the same small arteries identified on the original arteriogram. Occasionally, Ivalon may have only a temporary occlusive effect. A possible explanation for this phenomenon is proposed.  相似文献   
992.
In 151 years since first described, there have been 112 reported cases of hernia through the foramen of Winslow (HFW). All thus far have described HFW as a primary entity. The case reported appears to be unique with HFW as a surgical complication. HFW is the least common of internal hernias. The primary symptom is pain referred from the herniated organ and the hepatoduodenal ligament. An interesting sign is that the patient is found curled up or stooped over for pain relief. Anatomic factors implicated in HFW are an enlarged epiploic foramen, a floppy cecum and ascending colon, or abnormal length of small bowel mesentery. Tension on these structures causes pain with the torso extended. Distention of bowel in the lesser sac mimics gastric obstruction. Organs herniated are: small bowel (63%); cecum, ascending colon, and terminal ileum (30%); and transverse colon (7%). Of 25 cases reported since 1966, cecal herniation comprised two-thirds. The diagnosis may be made radiologically and the treatment is surgical. The case and a review of the literature are presented with attention to the anatomy. Also provided are the signs and symptoms of this interesting and perplexing diagnosis.  相似文献   
993.
Fungus balls of the renal collecting system are rarely of organisms other than Candida. A case of obstructing aspergilloma associated with acute ureteral colic is presented. The clinical features of this case are characteristic of renal aspergillomas in 10 additional cases described in the literature. Ten of the 11 patients were male. Each of the patients had an underlying disease that predisposed to fungal infection. Although all 11 patients were cured, diagnostic evaluation was often protracted as commoner causes of ureteral obstruction were excluded. Successful therapy required evacuation of the obstructing hyphal mass; open surgical procedures were necessary in five instances. Systemic amphotericin B should be reserved for patients with residual infection following removal of the fungus ball. This report emphasizes the need to consider aspergilloma in the differential diagnosis of acute ureteropelvic obstruction in the appropriate patient population.  相似文献   
994.
995.
996.
It was established by means of SDS polyacrylamide gel electrophoresis that direct injections of methyl mercury (10 micrograms Hg) into the mature rat vitreous body of the eye decrease protein synthesis in the retina and optic nerve at 4 hours after injection. Although the global spectrum of polypeptides did not change, a specific decrease in the volume of polypeptides of 20-23 K daltons molecular weight was evident. Conversely, systemic exposure to methyl mercury resulted in increased protein synthesis of polypeptides of 20-23 K molecular weight both in adult (8 mgHg/kg/day for 8 days) and neonatal rats (2 mgHg/kg/day for 10 days). In addition, specific changes in the volume of polypeptides 75-90 K molecular weight were noted in sciatic nerves of neonatal rats. These data are consistent with a bimodal response in protein synthesis following MeHg treatment. Local presence of MeHg following direct injection into the eye causes a reduction in protein synthesis, while chronic systemic exposure results in increased synthesis and transport of proteins in both mature and developing optic nerves and neonatal sciatic nerves. Thus, these systems possess the capacity to attempt regenerative processes through induction of a small subset of proteins known as GAPs (Growth-Associated Proteins) during the early stages of systemic methyl mercury exposure. These wide spread and system-specific changes are consistent with growth-specific functions during the early stages of methyl mercury exposure.  相似文献   
997.
Effects of human recombinant TNF on the tumor blood vessels and on the thrombus formation were investigated in relation to its mode of antitumor action against Meth-A sarcoma transplanted in BALB/c mice. The extent of the blood vessel lesion was evaluated by using transparent chamber placed in the mouse skin. Bleeding, hyperemia and congestion were observed at 1-2h, 4-6h and 24h after TNF (1 X 10(4)U/mouse) administration, respectively. In contrast, no histological changes in the normal blood vessels were observed microscopically following TNF injection. Thrombus formation was evoked in the tumor vessels 4h after TNF injection. However, when thrombus formation was prevented by heparin, no difference was observed among antitumor action of TNF against Meth-A fibrosarcoma necrotic response and the rate of complete cure. These results suggest that the direct effects of TNF causing lesions in the tumor blood vessels plays an important role in its antitumor action.  相似文献   
998.
999.
Clinical and biological data were evaluated using Desu univariate analyses or Cox multivariate analyses in a series of 1,777 chronic lymphocytic leukemia (CLL) patients from an Italian Cooperative Group. In univariate analyses, age and sex of patients, presence of bone marrow (BM; greater than or equal to 50%), and peripheral blood (PB; greater than or equal to 60,000/microL) lymphocytosis, anemia (hemoglobin [Hb] less than 11 g/dL), thrombocytopenia (less than 100,000/microL), direct Coombs' test positivity, hepatomegaly, splenomegaly, and extent of lymph node involvement were shown to be of significant prognostic value. Multivariate analyses, through a stepwise procedure, showed that the most important prognostic variables are Hb, hepatomegaly, lymph node involvement, PB lymphocytosis, and age and sex of patients. Further covariates would produce an improvement having a nonsignificant P value. Based on the results of multivariate analyses, a four-step staging using the significant variables of the Cox model is proposed.  相似文献   
1000.
The records of 29 consecutive patients treated by a pure, open, anterior acromioplasty were reviewed retrospectively. Excluded from consideration were patients with the following pathologic diagnoses or histories: (1) previously attempted acromioplasty on the same shoulder; (2) intraoperatively confirmed rotator cuff tear; (3) any surgically treatable biceps tendon or acromioclavicular abnormality; (4) lost to follow-up study. Three different techniques were employed to perform the acromioplasties. The first technique required partial deltoid origin detachment with an osteotome. The second technique spared the deltoid origin, while again using an osteotome to perform the acromioplasty. The third technique also spared the deltoid origin but used a high-speed burr to perform the acromioplasty. Evaluated in terms of patient satisfaction, residual pain, length of convalescence, suboptimal results, and complications, the first technique proved to be the least effective. The second technique produced early, excellent results. The third technique, in which a burr was employed through an intact deltoid origin, was most effective; technically, the method was also relatively simple and reliable.  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