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   58175篇
  免费   3994篇
  国内免费   229篇
耳鼻咽喉   684篇
儿科学   1493篇
妇产科学   1091篇
基础医学   7264篇
口腔科学   954篇
临床医学   5611篇
内科学   11902篇
皮肤病学   719篇
神经病学   5561篇
特种医学   2022篇
外国民族医学   4篇
外科学   9855篇
综合类   855篇
现状与发展   1篇
一般理论   69篇
预防医学   5108篇
眼科学   1186篇
药学   3570篇
中国医学   62篇
肿瘤学   4387篇
  2023年   220篇
  2022年   422篇
  2021年   997篇
  2020年   560篇
  2019年   949篇
  2018年   1165篇
  2017年   800篇
  2016年   893篇
  2015年   998篇
  2014年   1650篇
  2013年   2454篇
  2012年   3581篇
  2011年   3892篇
  2010年   2213篇
  2009年   2040篇
  2008年   3510篇
  2007年   3694篇
  2006年   3684篇
  2005年   3761篇
  2004年   3714篇
  2003年   3374篇
  2002年   3300篇
  2001年   477篇
  2000年   361篇
  1999年   568篇
  1998年   773篇
  1997年   657篇
  1996年   592篇
  1995年   566篇
  1994年   498篇
  1993年   446篇
  1992年   362篇
  1991年   367篇
  1990年   301篇
  1989年   315篇
  1988年   295篇
  1987年   279篇
  1986年   262篇
  1985年   304篇
  1984年   473篇
  1983年   405篇
  1982年   525篇
  1981年   513篇
  1980年   501篇
  1979年   250篇
  1978年   295篇
  1977年   288篇
  1976年   221篇
  1975年   218篇
  1974年   235篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors.  相似文献   
42.
43.
Between 1954 and 1986 inclusive, 160 children in the North West Region of England were registered with histologically proven lowgrade astrocytomas (grade 1 or 2). Ten died before receiving any treatment, and a further seven died within 28 days of surgery, leaving 143 children whose survival in relation to treatment modality is the subject of this paper. Low-grade astrocytomas are responsive to radiation therapy. This treatment has no clear benefit to offer children with superficial tumours that can be resected completely or nearly so, but significantly improves survival rates when tumours are deep-seated and not amenable to excision.  相似文献   
44.
The results of systemic autonomic nerve function studies in patients with closed-angle glaucoma and ocular hypertension are reviewed. Autonomic neuropathy has been demonstrated in 58% of patients with closed-angle glaucoma and 42% of ocular hypertensive subjects, with significantly increased prevalence in ocular hypertensives with narrow iridocorneal angles. The implications are discussed, with particular reference to the pathogenesis of raised intraocular pressure.  相似文献   
45.
46.
Background: Patients who suffer with gastroesophageal reflux Disease (GERD) endure a worsening of symptoms as their weight increases. When medical treatment of this condition in the morbidly obese patients fails, surgical intervention may be indicated. Choosing a procedure which not only helps achieve weight control but which also relieves symptoms and complications of GERD is the goal. We present a review of patients who have undergone Roux-en-Y Gastric Bypass (RYGBP) and related procedures for this disease. Methods: One hundred eighty-eight patients undergoing surgery for morbid obesity and for GERD in 1992-1996 were contacted by mail or phone. All of these patients had undergone preoperative esophagogastroduodenoscopy to grade the severity of their disease. Their preoperative symptoms were compared to those experienced postoperatively. Results: One hundred thirty patients underwent a RYGBP with modified Hill fundopexy, 22 patients underwent a distal gastrectomy with modified Hill fundopexy, 8 patients underwent distal gastrectomy alone and 28 patients underwent RYGBP alone. There have been no deaths. There were nine surgical complications, eight early and one at 2.5 years postoperation. Follow-up is 4-48 months. The average BMI dropped from 43 to 30.2 kg/m2. Whereas all patients were on some form of medical therapy before surgery, only 14 reported the need for medication postoperatively. Conclusions: Surgical intervention for weight control and treatment of GERD has been highly successful in our experience both with respect to weight control and to the reduction of reflux symptoms. Depending upon endoscopic and operative findings a RYGBP with or without an antireflux procedure can provide dramatic improvement. Gastrectomy with antireflux modifications is appropriate in selected cases.  相似文献   
47.
Three saxophone players with upper limb amputations have been successfully rehabilitated to play their musical instruments using skin-conductivity touch control. Each attained a standard of musicianship sufficient to perform the standard repertoire of the instrument in a concert setting. The mechanical and electrical modifications to the saxophone are described, as well as the principles of operation of the skin-conductivity touch control module. The touch control module is commercially available for prosthetists who wish to fit musicians or others with upper extremity amputations who require rapid accurate control of a number of channels of powered prosthetic function.  相似文献   
48.
A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, betweengroup comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection. © 1993 Wiley-Liss, Inc.  相似文献   
49.
This study examined the effect of acute and chronic administration of the selective 5-HT3 receptor antagonist BRL 46470A, an analog of granisetron, on the number of spontaneously active dopamine (DA) cells in the substantia nigra pars compacta (A9 or SNC) and the ventral tegmental area (A10 or VTA) in the rat. In the A10 area, the acute administration of BRL 46470A decreased the number of spontaneously active DA cells at a dose of 0.1 mg/kg (0.28 μmol/kg) ip, yet increased the number of spontaneously active DA cells at a dose of 0.3 mg/kg (0.84 μmol/kg). The chronic administration (21 days) of BRL 46470A appeared to produce a multiphasic dose-response curve. Thus, the chronic treatment with BRL 46470A increased the number of spontaneously active A10 DA cells at 0.03 (0.084 μmol) and 0.3 mg/kg, but decreased the number of spontaneously active A10 DA cells at a dose of 0.1 mg/kg. In contrast, BRL 46470A did not decrease the number of spontaneously active A9 DA cells after either acute or chronic administration (0.01-0.3 mg/kg). However, BRL 46470A did increase the number of spontaneously active A9 DA cells at acute and chronic doses similar to those that were effective in A10. The iv administration of (+)-apomorphine (APO) not only failed to reverse the decrease produced by chronic administration of BRL 46470A at 0.1 mg/kg, but further decreased the number of spontaneously active A10 DA cells. Similar to the results obtained with granisetron, the pretreatment of naive rats with either 0.01 or 0.1 mg/kg iv of BRL 46470A significantly potentiated (2-fold) the suppressant action of APO on the basal firing rate of A10, but not A9 DA cells. Overall, our results indicate that similar to granisetron, chronic BRL 46470A at 0.1 mg/kg selectively decreases the number of spontaneously active A10 DA cells, via a mechanism not related to depolarization inactivation. Presently, it is not clear what factors may contribute to the multiphasic dose-response curve of BRL 46470A. © 1994 Wiley-Liss, Inc.  相似文献   
50.
Mesalamine is the therapeutically active moiety of sulfasalazine used to treat inflammatory bowel disease. A controlled-release mesalamine capsule (Pentasa) is designed to release the agent continuously, and largely unaffected by intestinal pH, throughout the small and large bowel due to a diffusion-dependent, semipermeable ethylcellulose coating. It is a safe and efficacious single agent for inducing remission and producing therapeutic benefit in patients with mild to moderately active ulcerative colitis (UC) (2 or 4 g/day) or Crohn's disease (4 g/day), as well as for significantly enhancing quality of life for patients with mild to moderately active UC (2 or 4 g/day). It is also effective for maintaining remission in patients with quiescent UC and Crohn's disease (4 g/day). Disease location (left-sided UC or pancolitis) did not affect the agent's effect in active disease or maintaining remission. Fewer treatment-related adverse events were reported with mesalamine than with placebo in treating UC. In the treatment of active Crohn's disease, data showed no statistically significant differences in response for patients with ileitis, ileocolitis, or Crohn's colitis. This formulation of mesalamine may also be a possible steroid-sparing agent for patients with either active or quiescent Crohn's disease.  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