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   4084393篇
  免费   303047篇
  国内免费   6977篇
耳鼻咽喉   57310篇
儿科学   134588篇
妇产科学   113373篇
基础医学   588505篇
口腔科学   117525篇
临床医学   374107篇
内科学   777123篇
皮肤病学   90603篇
神经病学   328428篇
特种医学   154700篇
外国民族医学   1285篇
外科学   610876篇
综合类   96163篇
现状与发展   16篇
一般理论   1613篇
预防医学   327643篇
眼科学   96740篇
药学   302254篇
  13篇
中国医学   8211篇
肿瘤学   213341篇
  2018年   44058篇
  2017年   33371篇
  2016年   37670篇
  2015年   42538篇
  2014年   60286篇
  2013年   91462篇
  2012年   124405篇
  2011年   132613篇
  2010年   78751篇
  2009年   74507篇
  2008年   124079篇
  2007年   131990篇
  2006年   133454篇
  2005年   129881篇
  2004年   125390篇
  2003年   119930篇
  2002年   116616篇
  2001年   181998篇
  2000年   187245篇
  1999年   158135篇
  1998年   46987篇
  1997年   41605篇
  1996年   41210篇
  1995年   39222篇
  1994年   36359篇
  1993年   34314篇
  1992年   125005篇
  1991年   121983篇
  1990年   118872篇
  1989年   114832篇
  1988年   106430篇
  1987年   104140篇
  1986年   98611篇
  1985年   94808篇
  1984年   71546篇
  1983年   61396篇
  1982年   36829篇
  1981年   33172篇
  1979年   67025篇
  1978年   47442篇
  1977年   39905篇
  1976年   37961篇
  1975年   40287篇
  1974年   48998篇
  1973年   46936篇
  1972年   44095篇
  1971年   41410篇
  1970年   38544篇
  1969年   36465篇
  1968年   33570篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Although the evidence is not conclusive, overall many sexual changes seem to occur in the climacteric years. It would be easy to propagate and perpetuate longstanding beliefs and myths that would do a great disservice to all of the women to whom our care is dedicated. In the coming years it is hoped that we shall learn more about how to understand these changes. In recent years the International Menopause Society has actively encouraged work in this area. An entire issue of its journal Maturitas is devoted to a series of scientific papers on sexuality in the climacteric years. For those who desire further reading that issue is strongly recommended. All medical professionals who come into contact with women during the climacteric years should be prepared to ask about sexuality and to deal with any concerns that arise. Taking a good sexual history along with a good general medical history and full social background is the best starting point for coping with these concerns. How to take a comprehensive sexual history is well described by Munjack and Oziel. Of course, it is not usual to take this full history on every woman with menopause symptoms. A few key questions should identify the woman who has sexual problems and facilitate selection of appropriate questioning for each patient (Table 2). Often, taking such a history allows the physician to identify a problem area that may be helped by medication or, more often, by education and simple office counseling. When it is clear that these simple approaches will not be adequate, the physician should have good resources for referral to the appropriate specialist, whether it be gynecologist, menopause center, psychologist, family therapist, or sex therapist.  相似文献   
994.
Is the driver drunk? Oculomotor sobriety testing   总被引:1,自引:0,他引:1  
Recently a new test involving observation of ocular pursuit movements, end-point nystagmus and angle of lateral deviation at which nystagmoid movements begin has been used by law enforcement agencies to determine the blood alcohol level of suspected drunk drivers. When properly administered and scored, this test can correctly identify approximately 80% of drivers with alcohol levels of 0.10% or greater. The test is more accurate than the traditional coordination or mental computation tests previously used, but questions may be raised about the use of the test with suspects who have ocular problems such as high refractive errors, chronic nystagmus, etc.  相似文献   
995.
Power density producing damage at a probability of 0.5 (ie, damage threshold, DT-50) was determined for PMMA (with/without UV absorber) and Silicone intraocular lenses. Scattered light from a collinear diagnostic He:Ne beam was one of four damage monitors deployed to enhance the sensitivity of the system. In order of increasing laser resistance the following results were obtained: injection molded PMMA (1.9/GW/cm2) Silicone (2.63 GW/cm2) Lathe-cut PMMA (4.47 GW/cm2), Lathe-cut PMMA with UV absorber (8.32 GW/cm2), Cast-molded PMMA (12.30 GW/cm2). An analysis of variance revealed interclass differences significant at the .01 level. Cast-molded PMMA was the most laser-resistant IOL material.  相似文献   
996.
Collagen, fibronectin and laminin are important components of the extracellular matrix of the human cornea. We used the immunofluorescence technique with polyclonal antibodies directed against these proteins and to bullous pemphigoid antigen (BPA), in order to study their distribution in human corneas from 8 weeks of gestation to term and in adult corneas. Immunoreactivity was observed with antibodies to type I collagen in the limbus and the corneal stroma at 8 weeks of gestation. At 11 weeks of gestation it was found in epithelial basement membrane (EBM) and Descemet's membrane (DM) and continued thus throughout fetal and adult life. Type II collagen was not detected in fetal or adult cornea. Type III collagen was detected during 8-20th weeks of gestation in the EBM, DM and stroma. After 27th weeks of gestation, type III collagen could no longer be detected in the central cornea. Type IV collagen was detected in the EBM as early as 8 weeks of gestation and remained positive throughout fetal and adult life. Descemet's membrane was negative for type IV collagen at 8 weeks of gestation and became positive thereafter. Immunostaining for fibronectin in DM was negative at 8 weeks of gestation, followed by patchy staining of corneal stroma and EBM up to the age of 37 weeks of gestation. Staining in the EBM was negative or variable up to 70 years of age, and then became positive again in a 77 year old individual. Staining for LN was positive in the EBM after 8 weeks of gestation. Staining was negative in DM at that age, but became positive after 9 weeks of gestation. Staining for BPA was negative at 8-9 weeks of gestation, then gradually became positive.  相似文献   
997.
A new rapid procedure for desiccating frozen resin-cracked retinal tissue for scanning electron microscopy (SEM) which permits air-drying was found to compare favorably with tissues prepared by critical-point drying: Retinal tissue was fixed in 4% phosphate-buffered neutral formaldehyde, dehydrated by means of graded ethanol, embedded in Epon, cracked and washed in propylene oxide. For desiccation, the specimens were immersed in hexamethyldisilazane (HMDS), air-dried and finally sputter-coated. The method is time-saving, gives extended information in SEM, and the number of good specimens is increased.  相似文献   
998.
999.
Perbendazole was given orally and subcutaneously to mice infected with Angiostrongylus cantonensis at different stages of infection. The subcutaneous route of administration was more effective than the oral one. On the 5th day after infection, the perbendazole had a higher efficacy than on the 10th day postinfection. This finding shows that perbendazole had complete larvicidal effect at early stages of infection.  相似文献   
1000.
Case-adjusted prospective reimbursement systems, such as resource utilization groups (RUGs), may promote nursing home cost containment, but they may do no better than existing systems at encouraging homes to admit the more dependent and thus costlier Medicaid patients, if the homes' reluctance to admit these patients is due to a shortage of nursing home beds. Using 1983 data on Wisconsin nursing homes, this paper presents evidence that suggests that the presence of excess demand, rather than low reimbursement rates, causes nursing homes to exclude the more costly Medicaid patients. Consequently, to benefit fully from RUGs, it is necessary either to eliminate excess demand (by increasing supply or decreasing demand) or to decide which patients have priority for admission and assign reimbursement payments to these patients that significantly favor these patients. Otherwise, access to nursing home care under RUGs is left to chance.(ABSTRACT TRUNCATED AT 250 WORDS)  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